United States . Office of Air and Radiation April 1993
Environmental Protection (ANR-443)
Agency Washington, DC 20460
& EPA Draft
Regulatory Support Document
Control of NOx and Smoke Emissions From
Nonroad Compression-Ignition Engines
Greater Than or Equal to 50 Horsepower
(37.5 Kilowatts)
-------
United States Office of Air and Radiation April 1993
Environmental Protection (ANR-443)
Agency Washington, DC 20460
& EPA Draft
Regulatory Support Document
Control of NOx and Smoke Emissions From
Nonroad Compression-Ignition Engines
Greater Than or Equal to 50 Horsepower
(37.5 Kilowatts)
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DRAFT
REGULATORY SUPPORT DOCUMENT
CONTROL OF NOx AND SMOKE EMISSIONS
FROM
NONROAD COMPRESSION-IGNITION ENGINES
GREATER THAN
OR
EQUAL TO
50 HORSEPOWER
(37.5 KILOWATTS)
April 1993
U. S. Environmental Protection Agency
Office of Mobile Sources
Certification Division
2565 Plymouth Road
Ann Arbor, MI 8105
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ACKNOWLEDGEMENTS
This Regulatory Support Document was authored by Mr. Ted Trimble, Ms. Deanne R.
North, Mr. Kevin A.H. Green, and Mr. Michael A. Sabourin of the Certification Division and
Mr. David A. Guerrieri of the Regulatory Development and Support Division. Technical
support was provided by the authors and other Certification Division and Regulatory
Development and Support Division technical staff including Mr. Mark H. Doorlag, Mr.
Richard P. Evans, Mr. John H. McCarthy, Mr. Michael J. Samulski, Mr. Todd L. Sherwood, Mr.
John F. Anderson, and Mr. Thomas M. Baines.
Ms. Jackie Lourenco and Mr. Scott Rowland of the California Air Resources Board
provided technical information and input into the analyses described in this document. EPA
appreciates their input and would like to thank the California Air Resources Board for their
cooperation with EPA.
Members of the Engine Manufacturers Association (EMA) and the Equipment
Manufacturers Institute (EMI) provided EPA with input on the technical aspects of the engines
and equipment potentially impacted by the proposed emission standards. A number of
manufacturers provided essential test data, production engines for testing, or prototype
engines for testing. These manufacturers include Deere & Company; Cummins Engine
Company, Inc.; Caterpillar, Inc.; Ford New Holland, Inc.; Detroit Diesel Corporation; Lister-
Petter, Inc.; Deutz Corporation; Teledyne Total Power; Kubota Tractor Corporation; and
Yanmar Tractor Service (U.S.A.), Inc.. EPA sincerely appreciates the cooperation of industry in
EPA's technical evaluation of these engines and equipment.
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TABLE OF CONTENTS
Introduction 1
Chapter 1: Environmental Benefit 3
1.1. Estimated NOx Emissions Reduction 4
1.1.1. Per-Engine NOx Emissions Reduction 4
1.1.1.1. Annual Reduction 5
1.1.1.2. Lifetime NOx Reduction 6
1.1.2. Aggregate Source NOx Reduction 8
1.1.2.1. Sales 8
1.1.2.2. In-Use Population 11
1.1.2.3. Aggregate Source NO„ Emission Inventory 11
1.2. Air Quality Benefits 13
1.2.1. NOx 13
1.2.1.1. Health and Welfare Effects of NOx Emissions 14
1.2.1.2. Health and Welfare Effects of Tropospheric Ozone 15
1.2.1.3. Roles of VOC and NOx in Ozone Formation 17
1.2.2. Smoke 19
Chapter 1: References 21
Chapter 2: Technological Feasibility 23
2.1. Emission Measurement 24
2.1.1. Test Cycle 24
2.1.2. Proposed Test Procedures 31
2.1.3. In-Use NOx Deterioration 32
2.2. Technology 34
2.2.1. Feasible NOx Control Technology 36
2.2.1.2. Injection Timing 37
2.2.1.3. Fuel Pump and Injector Nozzles 39
2.2.1.4. Combustion Chamber Design 40
2.2.1.5. Derating the Engine 41
2.2.1.6. Increased Turbocharger Boost 42
2.2.1.7. Aftercoolers 43
2.2.2. Feasible Smoke Control Technology 44
2.2.3. Infeasible NOx Control Technology 46
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2.2.3.1. Addition of a Turbocharger 46
2.2.3.2. Electronic Control 47
2.2.3.3. Air to Air Aftercoolers 48
2.2.3.4. Exhaust Gas Recirculation 48
2.2.3.5. Aftertreatment Devices 49
2.2.4. Certification Fuels 49
2.2.4.1. Cetane Number (CN) 50
2.2.4.2. Low Sulfur 50
2.2.5. Useful Life of Engines 51
2.2.6. Market Penetration of NOx and Smoke Control Technologies 54
2.2.6.1. Industry Input 55
2.2.6.2. EPA Proposal 61
2.2.6.3. California 1994 Model Year Standards 62
2.3. Impact on Equipment 64
2.3.1. Reason for Concern 64
2.3.2. EPA Assessment 66
2.4. Impact on Performance 69
2.4.1. Fuel Economy and Power 69
2.4.2. Noise and Safety 73
2.4.2.1. Noise 73
2.4.2.2. Safety 74
2.5. Feasible Emission Standards 74
2.5.1. Effect of Available Technologies on Emissions and Performance ... 75
2.5.2. Leadtime and Cost 80
2.5.3. Effect on Engines Below 175 Horsepower 81
2.6. Lowest Feasible Emission Standard 84
2.6.1. Lowest Feasible NOx Emission Standard 85
2.6.1.1. Technology Required for Lower than Proposed NOx
Standard 86
2.6.1.2. Timeline Constraints of a Lower NOx Standard 87
2.6.1.3. Ability of Proposed Test Procedures to Measure
Emissions From Nonroad Engines Built to Meet a Lower
NOx Standard 90
2.6.1.4 Conclusion 95
Chapter 2 References 97
Chapter 3: Cost 99
3.1. Variable Hardware Cost 100
3.1.1. Estimation of Weighted Average Variable Hardware Cost Per
Engine 100
3.1.2. United States Consumption 102
3.1.3. Annual Variable Hardware Cost 105
ii
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DRAFT
3.2. Production Cycle Fixed Costs 106
3.2.1. Engineering Development Costs 106
3.2.1.1. Engine Recalibration 106
3.2.1.2. Development Costs 107
3.2.2. Mechanical Integrity Testing Costs 110
3.3. Test Facility Cost 111
3.4. Annual Administrative Cost 112
3.4.1. Certification 112
3.4.3. Averaging, Banking, and Trading 113
3.4.4. In-Use Enforcement Costs 114
3.4.5. Emission Defect Reporting Costs 114
3.4.6. Selective Enforcement Auditing Costs 114
3.4.7. Importation of Nonconforming Nonroad Engines 115
3.5. Consumer Cost 116
3.5.1. Increase in Retail Price 116
3.5.2. Engine Operating Cost 117
3.5.2.1. Fuel Cost 117
3.5.2.2. Maintenance Cost 118
3.6. Cost Summary 118
3.6.1. Accounting for Costs as They Occur 119
3.6.2. Accounting for Costs as They are Recovered 119
3.6.3. Evaluation of the Stream of Costs 119
3.7. Cost-Effectiveness of the Proposed Rule 120
3.7.1. Cost Per Ton of NOx Reduction 121
3.7.2. Comparison to Cost-Effectiveness of Other Emission Control
Strategies 121
Chapter 3: References 131
Appendix A: Supplementary Tables 133
Appendix B: Formation and Control of Pollutants 153
B.1. Oxides of Nitrogen, NO„ 153
B.2. Hydrocarbons 154
B.3. Carbon Monoxide (CO) 154
B.4. Particulates and Smoke 155
Appendix C: EPA/EM A Engine Test Program 157
Appendix D: Estimation of the Number of Engine Families 163
Appendix E: Hourly Test Length Estimate 166
111
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iv
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Introduction
This regulatory support document provides additional information in
support of the proposals made in the Notice of Proposed Rulemaking entitled,
"Control of Air Pollution From New Nonroad Mobile Source Engines:
Determination of Significance for Nonroad Sources and Emission Standards for
Emission of Oxides of Nitrogen and Smoke from New Nonroad Compression-
Ignition Engines at or Above Fifty Horsepower". This proposal would regulate
all new nonroad compression-ignition engines greater than or equal to fifty
horsepower (37.5 kw) except engines which propel or are used on marine
vessels, aircraft engines, engines which propel locomotives, and engines
regulated by the Mining, Safety, and Health Administration. The regulated
engines are hereafter referred to as "nonroad large CI engines." The goal of
this regulation is to substantially reduce NOx emission and smoke from
nonroad large CI engines beginning in the 1996 model year. EPA has
determined that the proposed regulation for NOx emission and smoke
standards is
• environmentally beneficial,
• technically feasible, and
• cost-effective.
EPA's rationale for these determinations will be addressed in the following
three chapters of this support document.
1
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Chapter 1: Environmental Benefit
This chapter presents the methodology used by EPA to quantify the
benefits that would be realized through the proposed NOx emission standard
for large nonroad CI engines. Benefits, in terms of oxides of nitrogen (NOx)
emission reductions, are presented in two forms: per-engine benefits and
aggregate source benefits. "Per-engine" benefits are the emission reductions
expected to occur during the life of an engine whose emissions are controlled
in response to the proposed standard. "Aggregate source" benefits are the
estimated, future nationwide NOx emission reductions from affected engines
Estimated "aggregate source" benefits illustrate the potential future effect of the
proposed standard on the emission inventory of this source. Air quality
benefits are discussed qualitatively for both the NOx and smoke emission
standards.
Many of the detailed results discussed below are presented in separate
tables included in Appendix A - Supplementary Tables. Tables which are
included in Appendix A are notated in the format A-## (e.g., A-01, A-02, A-
03). Document cites denoted in parentheses (e.g., (#)) are located at the end of
Chapter 1.
3
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4
DRAFT
1.1. Estimated NO- Emissions Reduction
To estimate the average annual NOx emissions per current nonroad large CI
engine, EPA used results from the Nonroad Engine and Vehicle Emission Studyi 1)
(i.e., the nonroad study) to represent the baseline emissions (i.e., emissions
without controls). In that study, total emissions were calculated for each type
of equipment using
For the benefits analysis described here, EPA performed separate
calculations for the following horsepower ranges because the applicable
standards have separate implementation dates: (i) 50-100 HP, (ii) 100-175 HP,
and (iii) over 175 HP.1 Tables A-01 and A-02 show nonroad study data used
to construct Inventories A and B. As discussed in the nonroad study,
population and activity information used to construct Inventory A relied
predominately on data available in a commercially available data base, while
that used to construct much of Inventory B relied on data provided by
manufacturers and manufacturer associations.(2)
1.1.1. Per-Englne NO, Emissions Reduction
This section describes the calculation of the per-engine emission reductions
which are expected to occur during the life of an engine whose emissions are
^S^N^HP^LOAD^HOURS^EF^
In this equation,
N,
HP„vg
LOADMVg - ratio (%) between average operational power output
and rated power
HOURSMVg - average annual hours of engine operation
EF1
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DRAFT 5
controlled in response to the proposed standard. The annual per-engine NOx
emission reduction and the lifetime per-engine NOx reduction calculations are
described and summarized in this section.
1.1.1.1. Annual Reduction-For the baseline scenario, EPA calculated average
annual per-source emissions using
yi MASSt
LNi
i
Here, the summations are taken over those types of equipment with engines
that, on average, fall in the applicable rated horsepower ranges. The average
annual per-source NOx emissions in that range is then given by MASSavgJSIOx.
EPA calculated baseline per-source emissions using NOx emission factors
given in the nonroad study. To obtain average annual per-source emissions
for engines controlled to the levels required to comply with EPA's proposed
NOx emission standard, EPA recalculated the results using 6.9 g/bhp-hr in
place of the nonroad study emission factors.
The results of this calculation using data from both Inventory A and
Inventory B are presented in tables A-03 (50-100 HP), A-04 (100-175 HP), A-05
(over 175 HP), and A-06 (all engines over 50 HP). Due to the fact that the
overall results for all of the horsepower ranges are similar for Inventories A
and B, EPA used the average results calculated above in the remainder of the
analysis rather than carrying separate figures. The averaged results are
summarized below in Table 1-01, which shows that, for the less powerful
engines, 39% reductions would be realized, while for the midrange and more
powerful engines, reductions of 35% and 33%, respectively, would be attained
Table 1-01 also indicates that the proposed standard represents, on average, a
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6 DRAFT
37% reduction in annual NOx emissions from engines to which the standard
would apply.
1.1.1.2. Lifetime NO, Reduction-Because the average annual emissions
calculated above would occur over the lifetime of a given engine, EPA has also
estimated the lifetime per-source reduction in NOx emissions from the baseline
that would be obtained if engines were to meet the proposed standard. In
doing so, some estimate of the engine survival rate was needed. For all of the
engines included in this proposal, EPA relied on the estimate of engine
survival probability that was
Table 1-01
Nationwide Large Nonroad CI Engine Population,
Baseline and Controlled Annual Per-Engine Emissions
Nationwide
Population
Annual Per-Source NO, (tons)
Baseline
Controlled
50-100 HP
3,264,500
0.38
0.23
100-175 HP
791,000
060
0 39
over 175 HP
303,500
1.42
096
total over 50 hp
4,359,000
0.49
0 31
presented by Energy and Environmental Analysis (EEA) in a 1988 report to the
California Air Resources Board (CARB).(3) Table A-07 presents the likelihood,
given an engine's age, that it remains in service.
EPA also relied on the estimates contained in the EEA report to CARB of
the change in annual usage over the useful life of an engine. For each year in
an engine's useful life, the annual usage (hours) is expressed in Table A-07 as
a percentage of the annual usage averaged over the entire useful life of the
engine. As annual emissions are directly related to annual usage, EPA
calculated lifetime per-engine NOx reductions using
In the following formula,
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DRAFT
7
j-30
AN RED,
UFERED
NQxflvg
LIFEREDNOx
s
ANREDNOx/avg
the age of the engine
the likelihood that an engine of age j remains in
service,
the average annual reduction in per-engine NOx
emissions (grams),
the relative annual usage of an engine of age j
(i.e., the ratio of HOURS, to annual hours of use
averaged over the life of the engine),
the lifetime per-source reduction in NOx
emissions (grams).
Because the reductions calculated above occur as a stream of annual
reductions occurring over the lifetime of the engine, EPA also calculated the
discounted "present value" of the reductions - the equivalent year-of-sale
reductions (LIFEREDNOx,disc) of the entire stream. This was accomplished
using
Here, the interest rate used for discounting is indicated by r. EPA guidance(4)
on discounting provides a resolution to the dilemma of how to account for
both displaced private investment and foregone consumption in evaluating
environmental regulations. A brief summary of the approach is provided in
Section 3.6.3. of this document. The relevance to the present section is,
however, that benefits are discounted at the social rate of time preference,
which is presumed in the economic literature to be substantially less than the
opportunity cost of capital (and thus can be approximated by the consumption
rate of interest). This after-tax rate is estimated in the Supplemental Guidelines
on Discounting to be at most three percent. This analysis proceeds on the basis
that a three percent rate is appropriate for discounting future emission benefits
UFERED,
NQx^Usc
ANREDNQxfiVgx
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8
DRAFT
for these engines. Table 1-02 shows the average lifetime per-engine NOx
emission reductions without discounting and with 3% discount rates.
Table 1-02
Average Lifetime Per-Engine NOx Reductions
Discount Rate
Lifetime NO, Reduction (tons)
none
2.94
3%
2 33
1.1.2. Aggregate Source NOx Reduction
The calculation of aggregate source NOx reductions is described in this
section. The calculation takes into account U.S. consumption of these engines,
the U.S. population of these engines, usage, and related survival rates of these
engines as described below. Together with estimates of the emissions from
these engines, EPA has derived projected nationwide annual NOx emissions
from these engines through 2026.
1.1.2.1. Sales-To estimate future emission levels, some projection of the
future population of uncontrolled and controlled engines is needed. Because
engines are introduced into the field through sales, estimates are needed not
only of sales prior to the standard, but also of sales after the standard goes
into effect. For years between 1965 and 1990, sales of nonautomotive diesel
engines are reported by the U.S. Department of Commerce (DOC). For this
analysis, EPA has assumed that 70% of these are sold into applications covered
by the current proposal. This estimate is based on the portion of sales that,
coupled with the estimated survival rates described above, lead to the average
population estimate made in the nonroad study.
Although figures for total U.S. engine production are given for each year
during this period, data for apparent U.S. consumption and for engines
produced and incorporated into products used at the same establishment
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DRAFT
9
("internal consumption") are only given for 1978 and 1980-1990. For other
years from 1965-1990, EPA estimated U.S consumption and "internal
consumption" by regressing data for 1978 and 1980-1990 against total U.S.
engine production, and applying the regression results to U.S. engine
production for 1965-1977 and 1979.
For 1960-1965 and 1990 to 2026, EPA estimated sales assuming a 2% rate of
annual growth in total U.S. consumption. This is based on estimates of long-
term growth of the economy, the internal combustion engine industry, the
farm machinery and equipment industry, and the construction machinery
industry.2 EPA expects that this approach will better represent long-term
trends than an approach that relies solely on DOC(5) diesel engine apparent
consumption data, which only is available for the 1980s.
The results of this analysis are summarized in Table A-08 in Appendix A,
which presents figures reported by DOC and estimates made by EPA. Figure
1-01 shows the estimated sales of engines affected by this proposal that was
used in the remainder of the analysis. These sales estimates and projections
are for all nonroad compression ignition engines included in the current
proposal. For the remaining analysis, EPA assumed the following distribution
of sales to the different horsepower ranges included in the proposal.
This distribution is based on the population distribution observed in the
nonroad study average results given in Table 1-01.
It should be recognized that, while national growth is measured at the level
of the economy as a whole, growth in specific areas of the country is likely to
vary from area to area in response to the specific demographic and commercial
Horsepower Range
50-100
100-175
175+
Portion of Sales
75%
18%
7%
2
The rationale for growth in sales is further explained in Section "3 1 2 United States Consumption
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DRAFT
Z010
Year
Figure 1-01
Estimated U.S. Sales - 1960-2026
Nonroad CI Engines Over 50 HP
trends in those areas. These effects should be considered in estimating growth
at the local level.
Because the proposed standard would begin to take effect in 1996, EPA
distinguished between sales of controlled and uncontrolled engines from 1990-
2026. Beginning in 1998, all engines sold are assumed to comply with the
proposed standards. Although the proposed averaging, banking and trading
(ABT) provisions allow for engines to emit at rates above the standard, they
must be balanced by cleaner (i.e., below the standard) engines. Consequently,
the fleet as a whole should emit at or below the proposed standard. Table 3
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11
presents estimated sales of complying engines by horsepower range for
1995-1999, as these years bracket the phase-in period.
Table 1-03
Projected Consumption of Complying Engines
1995-1999
-Complying Sales
Year
All
<100HP
100-175HP
>175HP
1999
338,697
253,645
61,467
23,585
1998
332,056
248,672
60,262
23,123
1997
81,749
0
59,080
22,669
1996
22,225
0
0
22,225
1995
0
0
0
0
1.1.2.2. In-Use Populatlon-By coupling the sales estimates and projections
given in Table A-08 with the engine survival rate function described in Table
A-07, EPA calculated the estimated population from 1990-2026 of engines
addressed in the current proposal. In doing so, EPA distinguished between
controlled and uncontrolled engines, so that the effect of the standard could be
ascertained. Tables A-09 and A-10 show the resulting projections for 1990-2026
for all engines and for controlled engines, respectively. These projections are
summarized in Figure 1-02, which presents the projected total engine
population and the portion that would be controlled in response to this
proposal.
1.1.2.3. Aggregate Source NO, Emission Inventory-EPA projected future annual
nationwide NOx emissions from engines addressed in this proposal under the
baseline (no controls applied) and controlled scenarios. This was accomplished
using
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DRAFT
r\
a
i
o
in
A
0)
(A
0)
¦0
a
o
L
C
C
0
+J
ojooooo
1990
2030
AI I EngInes
¦Control led Engines
Figure 1-02
Estimated U.S. Population - 1960-2026
Large Nonroad CI Engines
j-i
MASSNQxo= (SALESjXSy.jxAUrdj.jxMASScvgjfQxj)
J~y-31
In this equation,
y
j
SALES,
y-i
inventory year
year of sale
engine sales in year j
fraction of engines sold in year j that survive in
year y (from Table A-3)
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DRAFT
13
AUre) y., - relative annual usage in year y of engine sold in
year j, as percent of average annual usage over
engine life (from Table A-3)
MASSavgJS)CbM - average annual per-engine NOx emissions of
engines sold in year j (from Tables 1-01,1-02,1-03)
For each year, this calculation is carried out for each of the three applicable
rated power ranges (50-100 HP, 100-175 HP, and 175+ HP). The sum of these
three results yielded the total inventory of emissions from sources addressed
by the current proposal. The controlled and uncontrolled scenarios were
accounted for through MASSavgJS[0x). All other parameters were the same in
both scenarios.
Table A-ll presents total annual nationwide emissions from engines
addressed in this proposal under the baseline scenario, and Table A-12
presents results for the controlled scenario. These are shown graphically in
Figure 1-03.
In Figure 1-03, the annual benefit of the proposed regulation is indicated by
the difference between the upper and lower curves. The area between the
curves represents the net benefit of the proposed regulation during the time
required for the nonroad large CI engine fleet to completely turn over.
Discounted at 3%, the net present value of the stream of benefits projected to
occur between 1996 and 2025 is 13.1 million tons of NOx.
1.2. Air Quality Benefits
Air quality benefits associated with reduction in NOx and smoke are
discussed in this section. Health and welfare effects of the pollutants are
discussed. Further, the role of these pollutants in ambient air quality problems
are discussed.
1.2.1. NOx
EPA expects that reducing NO„ emissions from large nonroad compression
ignition engines will help to mitigate the health and welfare impacts of
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14
DRAFT
(D
T3
i
C
0
I
o
1990
2000
2010
2020
2030
Year
¦ Base I Ine
-With Control
Figure 1-03
Projected Nationwide Annual NOx Emissions - 1960-2026
Nonroad CI Engines Over 50 HP
ambient NO*, ambient particulate matter, acidic deposition, as well as urban
and regional tropospheric ozone formation and transport.
1.2.1.1. Health and Welfare Effects of NO, Emlsslons-NOx is the general term
used to denote oxides of nitrogen, primarily nitrogen oxide (NO) and nitrogen
dioxide (NOz). As stated previously, NOz is a criteria pollutant for which the
EPA has established a NAAQS.
At elevated concentrations, NOz can adversely affect human health,
vegetation, materials, and visibility. Although the NAAQS for N02 is
currently violated only in Southern California, EPA is concerned with
maintaining the standard in the rest of the nation and meeting Prevention of
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DRAFT 15
Significant Deterioration (PSD) requirements for N02 in areas that are currently
in attainment.
NOx emissions also react in the atmosphere to form particulate nitrates,
some of which may be toxic, mutagenic or carcinogenic.(6) These secondary
PM10 particles contribute greatly in some areas, especially parts of California,
to nonattainment of the NAAQS for PMl0, which applies to particles under 10
microns in diameter.(7) Because these small particles are carried deep into the
lung, they are known to cause potentially serious respiratory effects.
Particulate nitrates also contribute to impaired visibility, which, although not a
direct health problem, is perceived by the public as evidence of serious air
pollution.
Recent findings from a report by the National Academy of Sciences
(NAS)(8) on ozone provide support for electric utility NOx emission controls
within the acid rain program. NAS indicates that these controls would benefit
many areas, particularly in the northeastern United States by reducing not only
ozone levels but also acidic deposition.
Acidic deposition is composed of acidic aerosols-liquid droplets and solid
particles suspended in the atmosphere. Acidic aerosols are generated when
NOx either reacts to form nitrates or contributes to the formation of sulfates
from sulfur dioxide gas. Acidic aerosols can irritate the respiratory system and
increase the incidence and severity of respiratory diseases. Acidic aerosols can
also accumulate airborne heavy metals and toxic chemicals and thereby deposit
them in the most vulnerable areas of the lung. Interactions of ozone with NO,
and sulfur oxides may also contribute to the formation of acidic vapors which
might have a direct effect on health and welfare, as well as other indirect
effects following their deposition on surfaces.
1.2.1.2. Health and Welfare Effects of Tropospherlc Ozone-EPA's primary reason
for controlling NOx emissions from large nonroad CI engines is the role of NO,
in forming ozone (03). Of the major air pollutants for which NAAQS have
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16 DRAFT
been designated under the CAA, the most widespread problem continues to be
ozone, which is the most prevalent photochemical oxidant and an important
component of smog. Ozone is a product of the atmospheric chemical reactions
involving nitrogen oxides and other compounds. These reactions occur as
atmospheric oxygen and sunlight interact with hydrocarbons and nitrogen
oxides from both mobile and stationary sources.
A critical part of this problem is the formation of ozone both in and
downwind of large urban areas. Under certain weather conditions, the
combination of NOx and VOC can result in urban and rural areas exceeding
the national ambient ozone standard by a factor of three. The ozone NAAQS
represents the maximum level considered protective of public health by the
EPA.
Ozone is a powerful oxidant causing lung damage and reduced respiratory
function after relatively short periods of exposure (approximately one hour).
The oxidizing effect of ozone can irritate the nose, mouth, and throat causing
coughing, choking, and eye irritation. In addition, ozone can also impair lung
function and subsequently reduce the respiratory system's resistance to
disease, including bronchial infections such as pneumonia.
Elevated ozone levels can also cause aggravation of pre-existing respiratory
conditions such as asthma. Ozone can cause a reduction in performance
during exercise even in healthy persons. In addition, ozone can also cause
alterations in pulmonary and extrapulmonary (nervous system, blood, liver,
endocrine) function.
The current NAAQS for ozone of 0.12 ppm is based primarily on the level
at which human health effects begin to occur. However, ozone has also been
shown to damage forests and crops, watershed areas, and marine life.(lO) The
NAAQS for ozone is frequently violated across large areas in the U.S., and
even after 20 years of efforts aimed at reducing ozone-forming pollutants, the
ozone standard has proven to be exceptionally difficult to achieve. High levels
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DRAFT 17
of ozone have been recorded even in relatively remote areas, since ozone and
its precursors can travel hundreds of miles and persist for several days in the
lower atmosphere.
Ozone damage to plants, including both natural forest ecosystems and
crops, occurs at ozone levels between 0.06 and 0.12 ppm.(ll) Repeated
exposure to ozone levels as low as 0.04 ppm can cause reductions in the yields
of some crops above 10%.(12) While some strains of corn and wheat are
relatively resistant to ozone, many crops experience a loss in yield of 30% at
ozone concentrations below the NAAQS.(13) The value of crops lost to ozone
damage, while difficult to estimate precisely, is on the order of $2 billion per
year in the U.S.(14) The effect of ozone on complex ecosystems such as forests
is even more difficult to quantify. However, growth in many species of pine
appears to be particularly sensitive to ozone. Specifically, in the San Bernadino
Mountains of southern California, the high ozone concentrations are believed
to be the predominant cause of the decline of the endangered ponderosa
pine.(15)
Finally, by trapping energy radiated from the earth, tropospheric ozone
may contribute to heating of the earth's surface, thereby contributing to global
warming (i.e., the greenhouse effect).(16)
1.2.1.3. Roles of VOC and NO, In Ozone Formatlon-Both volatile organic
compounds (VOC) and NOx contribute to the formation of tropospheric ozone
through a complex series of reactions. EPA's understanding of the importance
of NO„ in this process has been evolving along with improved emission
inventories and modeling techniques. The role of NOx has been controversial
because, depending on local conditions, NOx reductions can either promote or
retard ozone formation near the emission source(s), while downwind ozone
concentrations will eventually decline in response to NOx reductions.
In general, the ratio between the ambient concentrations of VOC and NO,
in a localized area is an indicator of the likely effectiveness of VOC and/or
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18 DRAFT
NOx reductions as ozone control measures. If the level of VOC is high relative
to the level of NOx (that is, in a ratio of 20 to 1), ozone formation is limited by
the amount of NOx present, making reduction of NOx emission an effective
strategy for reducing ozone levels. Alternatively, if the level of VOC is low
relative to the level of NOx (that is, in a ratio of 8 to 1), efforts to control VOC
would be expected to be a more effective means of reducing ozone
concentration.
For many years, it was believed that ozone formation was VOC-limited in
most nonattainment areas. Consequently, although both NOx and VOC
emissions are regulated for certain source types, the primary focus of past
ozone abatement strategies has been VOC. However, many areas have yet to
attain the ozone standard. In recent years, state-of-the-art air quality models
and improved knowledge of atmospheric chemistry have indicated that control
of NOx in addition to VOC is necessary for effective reduction of ozone in
many parts of the United States.
Based upon recent scientific research, NAS has determined that in many
parts of the country NOx control is generally a very beneficial strategy for
ozone reduction. However, under some circumstances, NOx reductions
without accompanying VOC control may actually increase ozone in a few
urban cores such as downtown Los Angeles and New York City.(17) In the
recent report, researchers emphasize that both VOC and NOx controls are
needed in most areas of the U.S.(18)
Data presented in EPA's ROMNET study(19) indicate that a combined
VOC/NOx strategy would be more effective for ozone reductions than a VOC-
only strategy. Based on the results of the ROMNET study, increased emphasis
on NOx reduction is necessary to attain the ozone standard in the ROMNET
modeling domain.(20) The ROMNET report also stresses that in an effort to
bring nonattainment areas into compliance, controls must be applied both in
urban areas and in the outlying rural areas.
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DRAFT 19
In some areas, VOCs emitted by vegetation combined with NO* emitted by
human activity can contribute to summertime ozone levels significantly
exceeding EPA standards. For example, in some cities such as Atlanta, more
VOC may be emitted by vegetation than by human sources, thus increasing
the importance of NOx reductions. Ozone formation in many rural areas is
almost certainly controlled by NOx emission due to of the large VOC
inventories from biogenic sources such as crops and trees.
Although both the ROMNET and NAS studies stress the need for
additional NOx controls, the emphasis is not merely a NOx-only strategy.
Rather, the importance of both VOC and NOx in air quality management is
stressed.
1.2.2. Smoke
Smoke is defined as that portion of the particulate emissions that is visible
which is mostly composed of carbon. Smoke is composed of large, visible
particulate matter (above 10 microns) as compared to smaller particulate
matter which is composed of minute, invisisble particles below 10 microns.
Due to their size, the larger, visible smoke particles do not penetrate to the
deeper parts of the lungs during normal breathing but accumulate in the
upper respiratory tract, throat, and mouth or they are expelled from the body
upon exhale. Because smaller, invisible particles (those below 10 microns) are
more likely to stay in the air stream, they are more likely to make it to the
deeper parts of the lungs and remain there.(21) The effect upon human health
of the smoke particles is uncertain because the particles do not penetrate
deeply into the lungs. The particles which do penetrate deeply into the lungs
are thought to be a greater health hazard.
Smoke from any source has also long been considered a major aesthetic
nuisance. The large carbon particles remain suspended for long periods and
refract light, causing the negative environmental effect of reducing visibility.
These particles are often wet and cause costly damage through soiling of urban
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20 DRAFT
buildings, homes, cars, and other property, they also soil human skin and
clothes. There are substantial costs to society in terms of living with a dirtier
environment or alternatively, paying to clean it up. More than likely, reducing
smoke from engine exhaust prevents pollution at a lower cost than the cost of
paying to clean the soiling.
The offensive odor associated with diesel engine exhaust has a negative
impact on public welfare. It is mostly caused by aldehydes. However, many
people believe that there is a correlation, however weak, with smoke as well. It
is certainly realistic to assume that the large carbon particles, which disperse
and carry farther than the small invisible particles, carry the offensive odors
further and help them to persist longer.
The invisible portion of the particulates that a diesel engine emits (termed
particulate matter or PM) is the portion that has the greatest health hazard.
Those strategies which are usually used to limit or control smoke (e.g., leaner
fuel/air ratio, advanced end of injection, better mixing, better atomization) can
be relied on to control PM as well, especially when applied to uncontrolled
engines. As limits get lower and control strategies become more sophisticated
the correlation becomes weaker and control of smoke is a poorer control of
PM.
The public is uneasy about a highly visible pollutant that gets on them and
their property and has an uncertain effect on their health. They support the
elimination of smoke. A precedent for the reduction of smoke for purely
aesthetic reasons was the agreement in 1991 to reduce smoke from the Navajo
Generating Station, far from any nonattainment area, to increase the public's
right to an unobstructed view of one of our nation's national treasures, Grand
Canyon National Park.
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DRAFT
Chapter 1: References
1. EPA, Nonroad Engine and Vehicle Emission Study, EPA Report Number
21A-2001, Washington, DC, November, 1991.
2. EPA, Nonroad Engine and Vehicle Emission Study, EPA/21A-2001, 1991,
p. viii.
3. Energy and Environmental Analysis, Feasibility of Controlling
Emissions from Off-Road, Heavy-Duty Construction Equipment - Final Report,
Arlington, VA, December 1988, p. 6-19.
4. U.S. EPA, Office of Policy, Planning and Evaluation, Guidelines for
Performing Regulatory Impact Analysis, EPA 230-01-84-003, March 1991
5. U.S. Department of Commerce, Bureau of the Census, Current
Industrial Reports: Internal Combustion Engines, Report Number MA35L,
Washington, D.C.
6. California Air Resources Board, The Effects of Oxides of Nitrogen on
California Air Quality, Report Number TSD-85-01, March, 1986, p. iii.
7. California Air Resources Board, The Effects of Oxides of Nitrogen on
California Air Quality, Report Number TSD-85-01, March, 1986, p. v.
8. National Research Council, Rethinking the Ozone Problem in Urban and
Regional Air Pollution, National Academy Press, Washington, DC, 1991.
9. Fisher, D. and Oppenheimer, M., Atmospheric Deposition and the
Chesapeake Bay Estuary, Journal Ambio, Volume 20, pp. 102-108 (1991).
21
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22
DRAFT
10. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
11. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
12. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
13. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
14. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
15. U.S. Environmental Protection Agency, Review of the National Ambient
Air Quality Standards for Ozone - Assessment of Scientific and Technical
Information: OAQPS Staff Paper, EPA-450/2-92-001, June 1989.
16. National Research Council, Rethinking the Ozone Problem in Urban and
Regional Air Pollution, National Academy Press, Washington, DC, 1991.
17. National Research Council, Rethinking the Ozone Problem in Urban and
Regional Air Pollution, National Academy Press, Washington, DC, 1991.
18. National Research Council, Rethinking the Ozone Problem in Urban and
Regional Air Pollution, National Academy Press, Washington, DC, 1991.
19. U.S. Environmental Protection Agency, Regional Ozone Modeling for
Northeast Transport (ROMNET), Project Final Report, EPA-450/4-91-002a,
Research Triangle Park, NC, June, 1991.
20. National Research Council, Rethinking the Ozone Problem in Urban and
Regional Air Pollution, National Academy Press, Washington, DC, 1991.
21. Seinfeld, John H., Atmospheric Chemistry and Physics of Air Pollution,
1986, p. 66.
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DRAFT
Chapter 2: Technological Feasibility
To be technologically feasible by the proposed 1996 model year timeline,
there must be engine test procedures and engine technology available that,
when applied to large nonroad CI engines, allows these engines to meet the
proposed emission standards in production and in actual use. At the same
time, regulations that would require technologies that significantly impact the
design of the equipment on which these engines will be installed will push
back the timeline for implementation of the proposed rules and may diminish
the cost-effectiveness of the regulations. To verify technical feasibility, this
chapter will demonstrate the following.
• Adequate test procedures are available to predict the proposed levels
of oxides of nitrogen (NOx) emission and smoke reduction.
• Necessary technology is feasible to meet the proposed NOx and
smoke standards within the proposed timeline.
• Engine technology changes will not significantly impact equipment
design with respect to powertrain, packaging, and maintenance.
• Engine technology changes will have minimal impact on fuel
economy and power.
• On average, engine technology changes will not significantly impact
emissions of hydrocarbons (HC), carbon monoxide (CO), and
particulate matter (PM).
23
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24 DRAFT
2.1. Emission Measurement
In order for EPA to successfully regulate tailpipe emissions, test procedures
to accurately measure new and in-use engine emissions must available. This
section will discuss the feasibility of existing emission test procedures to
measure the proposed emittants at the proposed levels, and EPA's
determination that upfront durability demonstration will not be needed to
ensure full useful life emission compliance.
2.1.1. Test Cycle
EPA must ensure that manufacturers of nonroad engines produce engines
that will perform as required over a specific, repeatable test procedure. This
test procedure must supply EPA with a reasonably accurate approximation of
the actual emissions that an engine will discharge into the atmosphere in-use.
The approximation would be reasonable if the magnitude of emission
reduction demonstrated on the required test procedure should directionally
approximate the magnitude of emission reduction realized during actual in-use
operation of the engine. In the nonroad environment, one engine model is
likely to be used in a large number of equipment applications each with
potentially a wide range of in-use operation characteristics. It will take a
substantial amount of EPA time to develop a test procedure that would
represent the range of use experienced by a nonroad engine in actual use.
EPA is currently engaged in an analysis to determine the test method best
suited to actual nonroad engine operation. However, EPA has decided that a
meaningful first step in NOx emission reduction can be realized in the near
future from large nonroad CI engines using available test procedures. Two
procedures available at this time are the ISO-8178-1 engine test procedures for
nonroad engines developed by the International Standards Organization (ISO)3
The International Standards Organization (ISO) is an organization of national standards bodies united to
promote standardization worldwide ISO develops and publishes International Standards ISO facilitates exchange
of goods and services and fosters mutual cooperation in intellectual, scientific, technological and economic spheres
of endeavor ISO is affiliated with the American National Standards Institute
-------
DRAFT 25
and the Federal Test Procedure (FTP) for heavy-duty on-highway engines
developed by EPA. The rest of this section discusses the appropriateness of
these two test procedures for approximating large nonroad CI engine exhaust
emissions.
The ISO test procedures for nonroad engines (i.e., the "ISO procedures" or
"ISO-8178-1") were developed in response to early inquiries by governments in
the United States and Europe into the contribution of nonroad mobile source
engines to air emission inventories. Engine manufacturers established a
professional technical committee for the purpose of establishing a
"recommended practice" for the measurement of engine exhaust emissions so
that emission test results from all laboratories following these recommended
practices could be reliably compared. The ISO procedures include a steady
state test cycle comprised of a specified number of different load and speed
conditions called "modes". Emission measurements are taken once per mode
only after the engine reaches equilibrium temperatures in that mode. There
are eleven different modes, five load conditions at maximum rated speed, five
load conditions at maximum torque speed, and one idle mode. The goal is to
allow the engine manufacturer to test engines over these eleven modes then
calculate "emission factors" by weighting the modes to correspond to the
average, real in-use operation seen by the broad category of engines (as
defined in ISO-8178-1) in which the test engine falls. For some applications,
many of the modes do not occur and are weighted zero. Thus for a generator
set three of the modes would be applicable, for farm and construction
equipment eight modes, and different mode sets for other application
categories. If done properly the tests are repeatable and require relatively
simple dynamometers and exhaust sampling devices. The exhaust gas
sampling method most commonly used is a raw gas sampling system,
although the ISO procedures allow for use of a constant volume sampler (CVS)
if a manufacturer prefers.
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26 DRAFT
The ISO procedures do not incorporate all modes of operation seen in the
actual use of nonroad engines. EPA's concern over the impact of modal
CUMMINS ENGINE CO.
Example of Equipment With Stead; State
Duty Cycle
Agricultural Tractor
Turning
OPERATION
LOAD FACTOR
8 Minutes
SpMdfUM
IQMCondt
Mm and Turn
SpMd Mo
Sp«M Ratio
Figure 2-01
differences on the ISO procedure's ability to accurately predict the magnitude
of certain pollutants for which exhaust emission standards are not proposed in
the notice is discussed later in this chapter. Similar to the ISO procedures,
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DRAFT
27
nonroad engines do not experience frequent changes in hand or foot lever
position by the equipment operator. However, lever position changes do occur
and the ISO procedures don't collect emissions during lever position changes.
In contrast to the ISO procedures, data provided to EPA show that nonroad
engines do experience in use frequent changes in load and speed caused by
load fluctuations that occur while a piece of equipment is working. This is
typically referred to as "transient operation." For instance, shown in Figure 2-
01 during the 8 minute "steady state" plowing mode, the engine operates
within an operating range (shown in Figure 2-01 as an area with shading)
where the maximum speed attained by the engine in the operating range is
approximately 1.5 times the minimum speed. Further, the operating range
maximum torque (shown in Figure 2-01 as an area with shading) required
from the engine is over two times the minimum torque. The engine is
continuously operating within a range and not at a steady speed or load.
Because the engine is changing speed and load within the operating range, the
engine is experiencing transient operating conditions. The ISO procedures do
not account for these transient conditions, but only take an emission reading at
8 discrete stabilized points (typically referred to as "steady state" operation)
where no speed or load fluctuations are occurring to the test engine.
The on-highway engine FTP is a transient procedure developed to quantify
the exhaust emission generated by an average engine in a highway truck
which undergoes continuous variation of load and speed in actual use. The
engine operates over a continuous twenty minute operating cycle that consists
of following a defined speed/load trace. The engine experiences constant
variations in speed and throttle position while emissions are collected
continuously throughout the twenty minute cycle. To perform this test a
motoring dynamometer and a computer are required. The exhaust gas
sampling method also requires a CVS system.
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28 DRAFT
The on-highway FTP heavy-duty engine test procedures incorporates
modes of operation not seen in the actual use of nonroad engines. Similar to
the on-highway FTP, nonroad engines do experience frequent changes in load
and speed caused by work fluctuations that occur as a piece of equipment
performs a task. In contrast to the on-highway FTP, the nonroad operator
does not move the hand or foot lever that affects throttle position (controlling
engine speed) as often as an on-highway operator. Therefore, the constant foot
lever movement seen in the on-highway FTP is likely more frequent and rapid
than would occur in nonroad engine applications (such as exemplified in
Figure 2-01). Finally, there is also a part of the on-highway engine FTP which
requires that the dynamometer drive the engine, rather than the engine drive
the dynamometer. This part represents the on-highway truck inertia driving
the engine during deceleration or going down a hill. Due to their steep
gearing and lower operating speeds, nonroad engines are not driven by their
equipment nearly as frequently as occurs in on-highway trucks.
EPA has concluded that real in-use operation is likely somewhere between
the ISO engine test cycle and the on-highway engine FTP test cycle. The FTP
uses less power and is more transient in nature than the normal operation seen
by nonroad engines. The ISO test procedure, on the other hand, is more
steady state than the normal operation seen by nonroad engines. Should this
transient operation represent a significant part of the duty cycle of the average
nonroad engine, it would be important that EPA properly reflect the pollutants
emitted during this transient operation.
While acknowledging that neither procedure will perfectly reflect real in-
use operation, EPA with the cooperation of the Engine Manufacturers
Association (EMA) ran a test program to determine how well these two test
cycles could predict emission reductions (see Appendix C). Several back to
back emission result comparisons were made between the on-highway FTP
and the ISO test procedures. Eight engines were operated on both procedures,
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DRAFT 29
three by EPA, one by a manufacturer, and four by Southwest Research
Institute. These engines represented current production unregulated engines
(nonroad engines) and regulated engines (on-highway engines) built by five
different manufacturers and tested at three different laboratories. In the winter
and spring of 1992 a second series of tests was performed, again with the
cooperation of EMA (see Appendix C ). In the second series, one nonroad
engine and one on-highway version of the same engine model were tested
using both the FTP and the ISO test procedures.
The emission test results of 18 engine configurations (from the ten engines,
a portion of which were recalibrated and retested) are reported in Table C-01
of Appendix C. This table compiles the results from 10 engines described
above plus 8 cases where technicians retarded the injection timing on 4 of the
10 engines tested. Results are tabulated for each emittant for both test
procedures for all 18 engine configurations. The percent difference between
the emission test results measured over the two procedures is calculated for
each emittant for each engine. Positive numbers indicate that the FTP gave a
higher value. The differences are averaged for each engine group and the final
"Average % Difference" for each emittant recorded at the bottom of Table C-01
is the average of the averages and not the average of the 18 engine
configurations. These data are summarized in Table 2-01.
Table 2-01
Emission Difference Between the FTP and ISO
Pollutant
Percent Difference
HC
30%
CO
35%
NOx
3%
PM
27%
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30 DRAFT
Examining Table 2-01, the following results are observed.
• On average, the FTP produced about 3% more NOx than the 8-mode.
• The other three constituents average 27% to 38% lower on the ISO
test.
EPA concludes from these test results that initial levels of NOx emission
reduction can be measured using either the FTP or ISO test procedures. NOx
emission was relatively unaffected by the differences between the two test
procedures. It can be reasonably projected that actual in-use operation, which
is likely somewhere between these two cycles, would also show similar
emission results to these two test procedures. The major difference between
the FTP and the ISO test cycles is the higher level of transient operation
experienced over the on-highway FTP test cycle. It is consistent with scientific
theory that NOx should not be influenced greatly during transient operation,
provided no other engine parameters change (e.g., radical timing changes).
Refer to Appendix B.l for a further discussion of NOx formation during the
combustion process.
The data are inconclusive whether HC, CO, or PM emissions from nonroad
engines in actual use can be properly characterized using the FTP or the ISO
test procedures. The results show that there is a large difference in measured
emissions between the FTP and the ISO test procedures for these three
emittants. Furthermore, there is no pattern or consistency in the emission
offset between one test procedure and the other. This was not unexpected
since the FTP has a great deal more transient operation than the ISO test
procedures, and HC and PM emissions are known to be greatly influenced by
transient operation (see Appendix B.2 & B.4). Further study will be required
to better characterize the nature and level of transient operation experienced
by nonroad engines in actual use before deciding whether HC, CO, and PM
emission standards can be based on the ISO test procedures or whether a new
nonroad engine test procedure would be necessary to control these other
emittants. Based on this analysis, EPA concludes that the information is not
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DRAFT
31
yet available to propose effective nonroad large CI engine emission standards
for HC, CO, and PM.
2.1.2. Proposed Test Procedures
The engine industry recognized that legislative controls on the emissions
from nonroad engines would soon be on the European agenda. They
recognized the need for the development of test procedures that would be
appropriate for reciprocating internal combustion engines used in nonroad
applications. The International Standards Organization (ISO) proceeded to
produce a test procedure to measure emission from nonroad engines. The
resulting test procedure has been refined it over the years in an attempt to
develop test procedures that give accurate, repeatable results and could be the
basis for a harmonized certification procedure. ISO restricted its work to the
development of test procedures and did not propose limit values. The result
of this effort was ISO-8178-1, Revision 4, "Test Bed Measurement of Gaseous
and Particulate Exhaust Emissions from Reciprocating Internal Combustion
(RIC) Engines."
EPA's proposed test procedures in the NPRM described in the proposed
regulations (draft 40 CFR Part 89, Subpart D) were developed to correspond
with ISO engine test procedures more specifically titled "ISO-8178-1, Revision
4". EPA used Revision 4 to harmonize with the proposed California
regulations for nonroad farm and construction engines greater than or equal to
175 hp (131 kw). California developed their nonroad test procedures from
Revision 4, which is an early version of the ISO-8178-1 portion of the ISO
engine test procedures. These test procedures are also likely to be proposed to
the European community for adoption as their test procedures. There will be
at least one more revision to the ISO engine test procedures, which will
incorporate some of the changes that were made during the development of
draft 40 CFR Part 89, Subpart D (herein after termed "Subpart D").
Coordination is ongoing between EPA, CARB, and ISO technical personnel to
ensure compatibility between required and recommended test procedures.
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32
DRAFT
EPA developed its proposed regulatory test procedures (Subpart D) to be
compatible with ISO and CARB. However, while Subpart D meets all the
requirements of ISO test procedures, ISO-8178-1 test procedure may not meet
all the requirements of Subpart D.4 ISO test procedure recommended practices
are general enough to encompass all reciprocating internal combustion engines.
As Subpart D is only concerned with compression-ignition engines at or over
50 hp, some aspects of the ISO test procedures were inappropriate for
inclusion in Subpart D. Further, Subpart D is a regulatory document, and as
such, needs to clearly define test procedures and measurements. ISO-8178-1 is
a non-binding recommended practice, provides a range of specifications that
allow some differences between manufacturers' testing techniques while still
complying with ISO-8178-1.
Some examples of the differences between Subpart D and ISO test
procedures are listed in Table 2-02. The result of this development process is
an EPA proposed test procedure that is essentially a subset of both ISO engine
test procedures and the California regulations. This ensures that if an engine
is tested per the EPA proposed procedures, it could be considered to have met
the testing requirements as set forth by California or any European nation that
adopts the ISO test procedures.
2.1.3. In-Use NO, Deterioration
Analysis of on-highway historical data (10) leads to the conclusion that
heavy-duty diesel engines do not generally produce more NOx emission as
they get older. In the 1990 model year the average deterioration factor, as
determined by the durability data engines, was .247 or about 3.5% of the NOx
emission standard of 6.0 g/bhp-hr. The analysis also demonstrates that in-use
The EPA test procedures allow a manufacturer to use any temperature and pressure at the engine inlet as long
as it is used consistently ISO-8178-1 test procedure dictates a specific inlet temperature and pressure This is the only
condition where a manufacturer must use the ISO inlet conditions in order to be compatible. Also, EPA requires the
use of commercially available fuel within a specified range of properties ISO and CARB allow low sulfur fuel blends
not within EPA's range. A manufacturer would have to use EPA's fuel requirements Such a worst case fuel condition
would likely be accepted by CARB as compatible with its procedures
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DRAFT
33
Table 2-02
Differences Between ISO-8178-1 and EPA Subpart D
Parameter
ISO-8178-1
EPA Pari 89 Subpart D
Adjustments to
Measured Power
Output
Allows an accessory load to be added to
the power to correct to gross power
conditions if that accessory can not be
removed from the engine The power
correction can not exceed 5 percent of the
maximum observed power output
Does not allow for any adjustments to the
measured power output Accessory loads are
considered parasitic in nature and are
discouraged from being included dunng
testing. Tests should be conducted in gross
power conditions
Temperature
and Pressure
Specifications
Specifies standard conditions (STP) for
temperature and pressure (273K and
101.3kPa).
Allows any temperature and pressures as
long as consistency is maintained throughout
the test All measurements are on a mass
basis
Charge Air
Cooling
Simulation
Sets temperature and pressure limits for
charge air cooling according the
manufacturers recommended
specifications
Recommends SAE J1937 for charge air
cooling simulation
Air Cleaner
Restriction
Specifications
Specifies inlet pressure
restncbon to be set at the upper limit of a
clean air filter as specified by the
manufacturer.
The same as under ISO- 8178. However, the
manufacturer is liable for emission
compliance over the entire range of inlet
pressure restrictions as specified in the
manufacturers product literature
Exhaust
Restriction
Specifications
Specifies exhaust pressure restriction to be
set at the maximum (i.e., the upper limit)
pressure as specified by the manufacturer
The same as under ISO-8178. However, the
manufacturer g liable for emission
compliance over the entire range of exhaust
pressure restrictions as specified in the
manufacturers product literature.
Fuel Specifications
Does not specify particular test fuel
properties.
Defines fuel type and chemical
charactenstics
Alternate Emission
Sampling Equipment
Allows alternate sampling equipment and
systems if the equipment or system has
been checked by performing a correlation
study between the system under
consideration and one of an accepted
design.
Allows alternate sampling equipment and
systems only with pnor approval of the
administrator
Analyzer Response Time
Defines response time requirements for
analyzers.
Does not define response time. However,
response time must be accounted for before
sampling begins dunng a mode.
Sampling System
Characteristics
Is not very specific as to sampling system
characteristics (e g, temperature).
Is very detailed in its definition of sampling
system charactenstics.
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34 DRAFT
data extending over 400,000 miles shows a slight decrease in NOx emission
with mileage. Therefore, no durability data engines or deterioration factors are
proposed in this rulemaking.
Aftertreatment devices do deteriorate with use but EPA does not expect
that aftertreatment devices will be used for this rule. As long as aftertreatment
devices are not used, then this rule does not require a deterioration factor test.
2.2. Technology
To give some perspective on the types of emission control technology that
would be available to engine manufacturers, EPA looked at certified on-
highway engine families. As noted in Table 2-03, in the 1990 model year, the
on-highway heavy-duty engine emission standard for NOx emissions went
from 10.7 g/bhp-hr down to 6.0 g/bhp-hr. While, for reasons discussed in
Chapter 2.6, today's proposed NOx emission standard for large nonroad CI
engines is somewhat less stringent (i.e., 6.9 g/bhp-hr) than the 1990 model
year on-highway standard, the on-highway heavy-duty engine family
configurations certified and built in the 1990 model year represent the closest
approximation to the range of technologies that will be available to nonroad
engine manufacturers certifying to the standard proposed in the NPRM.
Table 2-04 was constructed from EPA's data base of certified engines to
assess the level of technology used in 1990 model year truck engines as well as
the magnitude of change in technology that occurred between the 1989 and the
1990 model year,. Information on the type of fuel pumps, injectors, and timing
are not available from this source, but there is information on the type of air
induction system used and whether electronic fuel control is used.
As seen in Table 2-04, between the 1989 and 1990 model year, naturally-
aspirated engines decreased to 8% of all engine families certified for 1990.
Aftercooled engines increased to 70% and air to air aftercoolers increased to
52% of all engine families in 1990. Electronic fuel control use rose to 16% in
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DRAFT
35
Table 2-03
On-Highway Engine Emission Standards
Year
grams/bhp-hour
smoke % opacity
HC
CO
NO,
PM
Acceleration
Mode
Lug Mode
Peak
Torque
1989
1.3
15.5
10.7
0.6
20
15
50
1990
1.3
15.5
6
0.6
20
15
50
Table 2-04
Change in On-Highway Technology Mix
in Percent of Total Engine Families (E.F.s)
From Data Base of Certificates
Model
Naturally
All methods of
Air-to-Air
Electronic
Total
Year
Aspirated
Aftercooling
Aftercooling
Control
E.F.s
1989
10%
50%
34%
8%
146
1990
8%
70%
52%
16%
160
% Change
-20%
40%
53%
100%
10%
1990. These percentages refer to engine families and may not be consistent
with sales data which is unavailable. Total engine families certified increased
by 14 families in the 1990 model year. Since manufacturers typically time the
introduction of new technologies with the introduction of new engine families
for cost and efficiency reasons, it is likely that these additional engine families
would have been equipped with turbochargers and air to air aftercoolers.
Most on-high way heavy duty compression-ignition engines sold in the 1990
model year use fairly sophisticated technology. These engines easily meet the
proposed standards and the technology is readily available. However, due to
the unique operating requirements , packaging constraints, and environment
faced by nonroad engines, or due to high relative cost, nonroad engine
-------
36
DRAFT
manufacturers will most likely choose not to use some of the on-highway
technologies in response to the nonroad regulations. The following examples
of infeasibility of specific technologies are discussed in Chapter 2.2.3..
• Turbocharging facilitates very effective emission control strategies
but turbochargers are difficult to apply, in many cases, because of
the extra room required.
• Aftercooling with air, the method of choice on-highway, is difficult
to apply to nonroad engines because lack of ram air means that a
larger fan is needed, a dirtier environment means more maintenance
or less effectiveness, and more room is required for the larger heat
exchangers.
• Electronic fuel control, although the wave of the future, is expensive
and manufacturers have doubts about the durability of current
control technologies.
These are technologies EPA has determined will not be necessary to meet
the nonroad engine NOx emission standard proposed in the NPRM.
2.2.1. Feasible NO„ Control Technology
In this section the technologies that are available for application to nonroad
engines will be presented with some assessment of each technologies
applicability and effectiveness in meeting the proposed nonroad engine
requirements.
To access the applicability of on-highway engine technologies to the
nonroad engine industry, it is necessary to access not only the available
technology, but also predict the percentage of the existing unregulated
nonroad engine population that already meet the proposed standards. That a
percentage of nonroad engines would already meet standards is not too
surprising. Many of the technologies used in on-highway engines have
already found their way to similar nonroad engines to provide greater power
and fuel economy and, in some cases, production uniformity and economy of
scale.
2.2.1.1 Percentage Requiring No Modiflcatlon-As part of its technology
assessment, EPA estimated the percentage of current production nonroad
engine designs capable of meeting the 6.9 g/bhp-hr (9.2 g/kw-hr) NOx
-------
DRAFT 37
emission standard with no modification. As its criterion, the Agency assumed
that engines that did not fall at or below the emission standard minus a
statistical safety margin (to minimize the risk of in-use failures due to
production variability and in-use deterioration) would have to be modified.
For this analysis the 13 percent average available safety margin observed in the
1990 model year on-highway program was used because it is the closest
approximation to what EPA expects to see for this proposal. Therefore, all
current production designs producing above a 6.0 g/bhp-hr (8.0 g/kw-hr)
NOx emission level would require modification to comply with the proposed
rule.
Table 2-05 shows the data of the current nonroad production engines that
were emission tested by EPA and EMA. While the engines tested in this
program were not randomly selected (but were provided by engine
manufacturers), these engines do represent a reasonable mix of the large and
small volume engine families in production in the nonroad market. Based on
these data, only the indirect-injected naturally-aspirated (IDI-NA ) technology
engine design was well below the standard. Without further information, EPA
is assuming that only this technology will generally escape some level of NOx
emission control. Since IDI engines represent 2% of engine families,
approximately 2% of yearly engine sales would not require modification under
this regulation. All other engines (98%) will require varying levels of
modifications to comply with the proposed NOx standard.
2.2.1.2. Injection Tlmlng-NOx control is achieved by retarding the start of
injection by a few degrees(5). The easiest way to do this is to retard the whole
injection process, thereby retarding the end of injection as well as the start.
Unfortunately retarding the end of injection shortens the time available to
complete the combustion process. As a result, HC, CO and PM pollutants and
fuel consumption are increased as NO, is being reduced.
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DRAFT
Table 2-05
Current Production Nonroad Engines
8-Mode Emission Test Results
Engine
Manufacturer &
Combustion
Chamber Type
Power
g/bhp-hr
(g/kw-hr)
smoke % opacity
HC
CO
NO,
PM
Accel
Lug
Peak
50 - 100 hp (37.3-74 6 kw) engines tested
Teledyne IDI
hp
66
0.19
2.57
5.4
1
12
21
22
kw
50
0 25
3.45
7.2
1.34
Confidential Dl
hp
51
0 92
394
12.5
0.44
kw
38
1.23
5.28
167
0.59
Ford NH Dl
hp
53
0.80
3.00
7.40
0.46
kw
39.5
1.07
4.02
9.9
0 62
Deutz Dl
hp
56
1.36
2.62
6.9
0.36
kw
39.5
1.74
3.51
9.2
0.48
Ford NH Dl
hp
67
0.98
8.80
7.10
0.64
kw
50
1.31
11.8
95
0 86
Ford NH Dl
hp
69
1 20
4 00
9 00
0 39
kw
515
1 61
536
120
0 52
John Deere Dl
hp
76
0.64
3.50
7.24
0.59
12
23
24
kw
56.7
0.86
2.82
9.7
064
average
under 100 hp
hp
62
0.87
4.06
7.93
0.54
12
22
23
kw
46.2
1.17
544
106
0 72
100 + hp (74.6 + kw) engines tested
Cummins Dl
hp
105
0.75
2.20
11.10
0.41
25
6
54
kw
78 3
1.01
2.95
148
0 55
Ford NH Dl
hp
130
0.70
5.58
9 27
0 96
11
26
27
kw
96.9
0.94
7.48
12.4
1.29
John Deere Dl
hp
141
0.43
3.14
11.76
0 42
13
9
22
kw
105
0.58
4.21
15 7
0 56
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DRAFT
39
Table 2-05
(cont)
Caterpillar Dl
hp
288
1.14
1 44
6.5
018
31
3
60
kw
215
1.53
1.93
8.7
0.24
Detroit Diesel Dl
hp
450
0.36
080
12.1
012
20
2
38
kw
336
0 48
1.07
16 2
0.16
average
hp
223
0.68
263
10.1
0.42
20
9
40
kw
166
0.91
3 53
135
0.56
EPA believes most of the 98% of uncontrolled engines that do not meet
the proposed NOx standard will have some retardation of injection timing. As
discussed in Chapter 2.4., sufficient retardation of injection timing to lower
NOx from current levels down to the proposed standard could cost about 3-5%
of fuel economy and power. Most manufacturers will have to apply additional
technology to recover the lost fuel economy and performance. These
additional technologies are discussed in the rest of this section.
2.2.1.3. Fuel Pump and Injector Nozzles-Improved fuel atomization reduces
the amount of injection timing retard required to meet the proposed standards.
To improve atomization, a manufacturer can improve its fuel delivery by
increasing fuel pump pressure, improving fuel pump advance strategies, and
incorporating smaller injector nozzle tip holes. When the liquid fuel is finely
atomized, combustion is improved in the combustion chamber. Ignition delay,
and thus NOx production, is reduced. Combustion is completed quicker and
HC, CO, and PM are reduced because the quicker combustion allows more
time for the oxygen to unite with the pollutants. Fuel consumption is also
reduced because the combustion takes place nearer Top Dead Center (since
injection is less retarded) and efficiency is increased. Many manufacturers
currently using rotary fuel injection pumps will incorporate higher pressure
rotary fuel injection systems to regain fuel economy and power. EPA expects
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40
DRAFT
that these manufacturers will not find it necessary, nor cost-effective to convert
to high pressure inline fuel pumps or unit injectors. Manufacturers that
already use inline fuel pumps or unit injectors will likely upgrade to higher
pressure units at little to no additional cost. Variable fuel injection timing
provides more flexibility to optimize a timing strategy. An optimized strategy
would both provide appropriate retardation of beginning of injection during
traditionally high NOx operating conditions, as well as minimize timing
retard during operating conditions that would compromise fuel economy or
power (i.e., engine efficiency). Because of the shorter time to achieve full
combustion afforded by systems designed with higher fuel injection pressures,
these systems can vary both beginning of injection and end of injection. This
allows the increased flexibility to both reduce NOx while minimizing power
loss by not retarding end of injection for NOx reduction under certain
operating conditions.
2.2.1.4. Combustion Chamber Design- The basic design of the combustion
chamber can impact emissions because it can substantially impact the means of
fuel delivery as well as the nature and the completeness of the combustion
process. There are two major distinctions in chamber design, indirect Injection
(IDI) and direct injection (DI). Sometimes called prechamber engines, IDI
engines have a small combustion chamber hollowed out of the cylinder head
(usually) or the piston. This prechamber is separated from the main chamber
by a narrow opening. The fuel is injected into the prechamber. Combustion
takes place at a richer air/fuel ratio within the prechamber, then exits the
prechamber with a high velocity to complete the combustion process amid a
high level of turbulence and mixing.
Characteristics of IDI engines are the following.
• Reduced emission of pollutants. NOx is lower(7) because of the rich
air/fuel ratio and resulting lower combustion temperature, and the
decreased detonation. Emissions of HC, CO, and PM are also
lowered due to the more complete utilization of the oxygen after
injection is over.
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DRAFT
41
• Higher compression ratio (20:1 to 25:1) needed for starting reliability,
increases friction.
• 5 to 10% lower fuel economy over a DI engine(6), primarily due to
the pumping losses (pushing air and combustion products back and
forth through the small opening exitting the prechamber uses
energy) and high friction from the high compression ratio.
• Higher speeds are attainable because the high velocity mixing and
turbulence helps the combustion process to proceed to completion
faster.
IDI is fast losing market share to DI because IDI engines have higher
fuel consumption penalty. This regulation should slow down the rate of
conversion of IDI to DI. However, very few if any small naturally-aspirated
DI engines would be converted back to IDI due to these proposals because the
cost of retooling would exceed other options for reducing NOx emissions from
DI engines.
Sometimes called "open chamber," DI engines usually have a flat
cylinder head with the combustion chamber hollowed out of the piston. The
chamber can be almost any shape but it is not restricted at the top. In effect
the fuel is injected into the whole mass of air. These engines have become
popular in recent years due to their lower fuel consumption. The majority of
large nonroad CI engines (about 98%) use this type chamber. Although DI
engines are at a disadvantage over IDI engines with respect to NOx emission,
there are a range of technologies, such as medium pressure injection systems,
that can reduce NOx emission at lower cost than converting a DI engine to IDI.
EPA has concluded that the level of standard proposed in this rule is not so
stringent as to require manufacturers to redesign DI engines to be IDI.
2.2.1.5. Derating the Englne-Another method by which manufacturers can
control emissions is to reduce the fuel flow to the engine, commonly referred
to as "derating." A great deal of engine development time is spent to
maximize the density of the air charge in a cylinder for each combustion cycle,
primarily because the air consumption effectively limits the amount of work
the cylinder can do. Increasing the fuel rate increases the work output and the
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42 DRAFT
emission factors, but specific emissions will decrease because the work output
increases faster than the emission factors up to a point. At some point,
depending on engine design but usually near the smoke limit, the emissions
will start to rise faster than the work output. Manufacturers will normally set
their engines at a "smoke limit" which generally means no visible smoke at full
load. There may also be a higher rating allowable for short periods when
some smoke is visible. The "smoke limit" will normally be at an air/fuel ratio
of about 21:1 or 22:1.
Derating is undesirable to the manufacturer because the engine's power
has been reduced, effectively reducing the engine's value. For example, a
manufacturer may have to sell for the same price an engine which now
produces 95 HP but which produced 100 HP in an earlier year. The
manufacturer could also certify a larger displacement version of the same
engine that has been derated from a higher horsepower down to the desired
100 hp. One manufacturer has indicated it is considering such a strategy to
replace one of its currently unregulated engine models. This strategy is most
likely to be used when both versions are already in production since the cost
to switch over is minimized. Packaging changes are minimized since the
differences would most likely be in the bore or stroke of the affected engines,
which has little or no impact on the exterior dimensions of the engine.
2.2.1.6. Increased Turbocharger Boost-To increase the air consumption of an
engine a manufacturer may install a pump to supply air at higher pressure,
thereby increasing the mass of air retained in the cylinder. There are a variety
of different pumps and methods of driving them available but the system of
choice today is a centrifugal compressor driven by a radial gas turbine and
colloquially called a "turbocharger," or more simply a turbo. The turbo packs
more air into the cylinder and thereby increases the air/fuel ratio, decreasing
emission factors, provided the manufacturer does not also increase the fuel
flow.
-------
DRAFT 43
Increasing the turbo boost on engines that are already turbocharged is
an effective, low cost means to regain the efficiency lost to retarding the
injection timing. Increasing air flow while maintaining fuel flow decreases HC,
CO, and PM emissions for the same reasons that they are reduced when
decreasing the fuel flow and maintaining air flow. NOx responds somewhat
differently, however. Since the same fuel amount is injected, the detonation
level in the combustion chamber stays similar to that level before the turbo
was added, while the increased mass of air provided by the turbo prevents the
peak combustion chamber temperature from rising as high as it did before
adding the turbo. Maintaining detonation level while reducing peak cylinder
temperature will result in lower NOx emission. Manufacturers do not usually
increase turbo boost to decrease emissions, but to decrease fuel consumption at
the same power level or to allow the manufacturer to increase fuel flow and
power for a relatively small cost. Use of turbo boost increase and/or
aftercooling substantially offsets any fuel economy penalty associated with
NOx emission reduction.
2.2.1.7. Aftercoolers-Like any other pump, the turbocharger heats the air
while compressing it. To further increase the air supply to an engine, a cooler
can be installed after the compressor and before the intake manifold. The effect
is to increase the mass flow of air (by increasing the density) and thus increase
the air/fuel ratio.
If fuel rates are not changed, aftercooling usually results in the reduction
of all four of the major pollutants. NOx is reduced due to the lower
combustion temperature. HC, CO, and PM are reduced because of the
increased amount of oxygen available to combine with these constituents.
Aftercooling with jacket water is an inexpensive and effective way to
gain increased air consumption and reduce NOx emission. EPA estimates that
about 10% of large nonroad CI engines will have aftercoolers added by the
1996 model year due to emission requirements (see Chapter 2.2.6.2, Table 2-10).
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44 DRAFT
2.2.2. Feasible Smoke Control Technology
The Federal Smoke Test and its standard values of 20% opacity for the
acceleration mode, 15% for the lug mode and 50% peak have been on-highway
requirements for a number of years. Three pairs of engines were tested
cooperatively with industry. This test program is described further in
Appendix C. Each pair of engines tested in the program consisted of a
production nonroad engine and an on-highway equivalent, or in the case of
the smaller engine, a prototype which represented an attempt to meet the 1996
California standards. One pair was turbocharged and aftercooled. One pair
was turbocharged. One pair was naturally aspirated.
The nonroad engine smoke results are shown in Table 2-06 and the on-
highway engine smoke results are shown in Table 2-07. Although the average
nonroad engine comes fairly close to meeting the smoke standard, Table 2-06
shows that each engine fails significantly in one or more modes. Table 2-07
shows that each of the on-highway and prototype engines is significantly
below the smoke requirements.
Table 2-06
Smoke Test Results - Current Nonroad Engines
Engine
Type
Rated
hp(Kw)
Technology
smoke % opacity
naturally
aspirated
turbo-
charged
after-
cooled
accel
mode
lug
mode
peak
Nonroad
283(211)
•
•
31
3
60
Nonroad
100(74.6)
t
25
6
45
Nonroad
72(53.7)
*
12
23
24
Average Nonroad Engine Smoke Results
23
11
43
Proposed Smoke Standards
20
15
50
-------
DRAFT
45
Table 2-07
Smoke Test Results - On-Highway and Nonroad Prototype Engines
Engine
Type
HP(Kw)
Technology
smoke % opacity
naturally
aspirated
turbo-
charged
after-
cooled
accel.
mode
lug
mode
peak
On-fiighway
285(213)
*
*
11
4
15
On-highway
105(78.4)
*
5
11
11
Prototype
73(54.5)
•
3
4
4
Average On-highway and Prototype Engine Smoke Results
6
6
13
Proposed Smoke Standards
20
15
50
To explain the smoke results reported above requires a short discussion
of why smoke occurs. Turbocharged engines are the most likely engines to
exceed smoke standards. When a compression-ignition engine is operating at
part load, the exhaust temperature is reduced and the turbocharger is
operating at reduced speed. To increase load, the fuel rate to the cylinder is
increased, which decreases the air/fuel ratio. If the air/fuel ratio is decreased
enough (below about 21:1), the engine will smoke. The increased fuel rate
increases the temperature of the exhaust which will accelerate the
turbocharger. It takes some time (turbo lag) for the turbine to come up to
speed in response to increasing exhaust temperature and restore the air/fuel
ratio to the "smoke limit". While the naturally-aspirated nonroad engine above
exceeded the "lug" standard, it is generally accepted (see Chapter 2.6.1) that
naturally-aspirated engines as a whole will not be as dramatically over fueled,
and thus will in most cases require only minor adjustments to meet the
proposed smoke requirements.
Strategies for decreasing "turbo lag" include use of low inertia
turbine/compressor wheels to increase the acceleration of the compressor, and
use of "smoke limiters" which may take the form of a dashpot in the pump
-------
46 DRAFT
linkage which slows down the rate of fuel increase, or an aneroid bellows
activated by turbocharger pressure from the intake manifold which limits the
fuel delivery until the turbine comes up to speed.
Manufacturers have stated that most turbocharged engines already have
a smoke limiter as an offshoot of standardization with similar on-highway
engine models. Turbocharged engines will need a smoke limiter to meet the
proposed smoke standards. Most existing smoke limiters will need some
adjustment to meet the new smoke regulations. Most naturally-aspirated
engines do not currently have smoke limiters. A small percentage of naturally-
aspirated engines may need a smoke limiter to meet the standards. Based on
manufacturers comments, it is projected by EPA that industry will use the
existing on-highway smoke limiter technology to control smoke emission in
engines subject to this proposal.
2.2.3. Infeaslble NO„ Control Technology
There are certain technologies that are used extensively in 1990 model
year on-highway engines that are either incompatible for use in nonroad
engine applications or are much more expensive than the alternative emission
control strategies and thus will not be used to attain the proposed level of NOx
emission control. The technologies that would in most cases fit this category
are discussed in this section.
2.2.3.1. Addition of a Turbocharger-The diesel industry is adding
turbochargers rapidly, independent of any emission regulations. Most large
engines already have turbochargers and they are being phased in at lower and
lower horsepower. The lower limit at which engines can be effectively
turbocharged today is about 30-40HP(22-30Kw). Turbochargers are generally
not fitted to decrease emissions, but to decrease fuel consumption at the same
power level or to allow the manufacturer to increase fuel flow and power at a
reasonable cost. While nonroad engine manufacturers do not have as strong a
market incentive to incorporate turbochargers on their engines as on-highway
-------
DRAFT 47
engine manufacturers,5 nonetheless use of turbochargers is increasing among
nonroad engine manufacturers as well.
Adding a turbocharger to a naturally-aspirated engine is one possible
method by which a manufacturer may regain the efficiency lost by retarding
injection timing to reduce NOx emission. The technical rationale is the same as
the reasoning stated for increasing turbo boost stated above. However, since
this proposal only regulates NOx emission and smoke, to add turbochargers to
those engines not currently so equipped would be costly compared to other
technologies available to meet the requirements of this rule (i.e., higher
pressure fuel injection systems).
2.2.3.2. Electronic Control-Technology exists to electronically control the
fuel system, the turbocharger, the transmission, slippage of the wheels, et
cetera. Use of electronic controls enables engine designers to minimize
emissions while maximizing fuel economy and performance. Manufacturers of
nonroad engines have resisted the use of electronic controls mainly due to cost
and reliability concerns. However, such systems have been in use for several
years in trucks and locomotives and the usage of such equipment is
expanding rapidly. Recent advertising by Cummins engine company suggests
that electronic controls will be introduced in the near future, citing advantages
in fuel efficiency, operating versatility, et cetera.(ll) This suggests that
electronically controlled engines could become popular on nonroad engines for
reasons other than emissions. EPA suspects that such a move by
manufacturers to produce and sell these systems would occur slowly, driven
by market forces rather than this rule. While use of electronic fuel control
systems could greatly benefit emissions, fuel economy and power, such
5 The incentive for on-highway manufacturers is that on-highway truck fleets owners shop around for menu«
that deliver higher fuel economy By contrast, nonroad engine users value durability and power over fuel in-n.-nu
The industry has stated that the critical fuel consumption design constraint for nonroad engine and m
designers is that a piece of equipment can only be refueled once per work shift This can be controlled by f\u I t
size and by engine fuel economy
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48 DRAFT
sophisticated controls will not be necessary to meet the proposed standards for
NOx emission and smoke.
2.2.3.3. Air to Air Aftercoolers-Air to Air aftercoolers are even more
effective than jacket water aftercoolers. The ambient air used as the cooling
medium starts out approximately 100 F (56 C) cooler than the engine coolant
used as the cooling medium for the jacket water aftercooler. A much denser
air charge can be delivered to the combustion chamber by the air to air system,
thus increasing efficiency and, again, reducing NOx emission even further.
For on-highway applications, which operate for long periods at higher
vehicle speeds (thus drawing a large volume of ambient air across the cooler
core at high speed) and draw air through the cooler from outside the engine
compartment, air to air aftercoolers are very efficient and their use has grown
quickly. Air to air aftercoolers are more difficult to apply to nonroad engines
than on-highway engines because they require design and implementation of
special hardware to maintain sufficient ambient air velocity past the cooling
fins and to keep dirt from building up around the cooling fins. To reduce dirt
around the engine, many nonroad applications also use pressurized engine
compartments which blow hotter engine compartment air through the
aftercooler, further reducing the coolers effectiveness. On-highway engines are
incorporating air to air cooler systems to help them attain very low NOx
emission levels between 4.0 and 6.0 g/bhp-g (5.3 and 8.0 g/kw-hr). Air to air
coolers will rarely be necessary to meet the proposed NOx emission standard
of 6.9 g/bhp-hr (9.2 g/kw-hr).
2.2.3.4. Exhaust Gas Reclrculatlon-Recirculating some of the exhaust gas
back into the ambient intake manifold is an effective way to reduce NOx
emissions(8,5), especially in naturally-aspirated engines, without increasing HC
or PM. Diesel manufacturers have been reluctant to use this technique,
however due to the following unresolved issues.
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DRAFT
49
• Sulfur and soot from combustion gases can cause increased wear of
piston rings, valves, and turbocharger components; and/or shorten
the oil change interval.
• If Exhaust Gas Recirculation cannot be introduced into the inlet of
the turbo compressor, then a more sophisticated pumping system
must be used to overcome the compression pressure in turbocharged
engines. (5)
Manufacturers do not generally use Exhaust Gas Recirculation for on-
highway engines and it is doubtful if any will employ it for this rule. Further
development and the use of low sulfur fuels for on-highway applications may
make this strategy more attractive, especially in small naturally-aspirated
engines. A more extensive discussion of low sulfur fuels follows in Chapter
2.2.4.2.
2.2.3.5. Aftertreatment Devices-After the exhaust gases have left the engine,
further reduction of pollutants can be achieved by catalytic converters and/or
particulate traps. Oxidizing catalysts can be particularly effective in reducing
CO or HC emission. PM can be oxidized as well or it can be trapped in a filter
which then is periodically cleaned.
NOx emission cannot easily be treated in diesel exhaust using catalytic
converters because compression-ignition engines always run leaner than the
stoichiometric air/fuel ratio. The excess oxygen makes the reducing catalyst
less effective. Manufacturers of heavy-duty diesel engines, both nonroad and
on-highway, have been reluctant to use aftertreatment devices because of cost,
complexity of installation (the engine manufacturer does not install the engine
in the vehicle), and durability concerns. As discussed further in Chapter
2.2.6.1, both EPA and engine manufacturers agree that aftertreatment devices
will not be necessary to meet the proposed requirements of this rule.
2.2.4. Certification Fuels
EPA believes that all manufacturers will be able to certify to the
proposed rule with available commercial fuels. EPA believes that certification
should be accomplished with the fuel most likely to be used in use. The
characteristics of fuel that have a direct impact on NOx emission and smoke
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50 DRAFT
are Cetane Number and fuel sulfur content. The sulfur content would not
likely affect NOx emission. However, it would impact PM emission and thus
may impact smoke emissions. These two characteristics should be within the
range of available commercial fuels in order to properly predict actual
emissions from nonroad engines.
2.2.4.1. Cetane Number (CN)~Since a great deal of the NOx emission is
formed during the detonation phase (see Appendix B.l), reducing the ignition
time delay, which will reduce the amount of fuel present in the combustion
chamber at the time of detonation, will reduce the detonation pressure and
temperature and less NOx will be formed. Raising the cetane number does
reduce the ignition delay period. Some tests done by McConnel in 1963 (2)
indicate a reduction of about 35% in NOx emissions when the cetane number is
increased from 35 to 59. More recently, Terry Ullman, et.al., found in 1990 that
changing cetane number from about 37 to about 55 decreased NOx by about
10%, HC by about 73%, CO by about 53% and PM by about 31%.(3)
In the winter of 1991, diesel fuel available in the United States had an
average cetane number of about 44.4.(4) The minimum was 37.8 and the
maximum was 58.5 for a spread of 20.7 numbers. The proposed regulations
would allow a cetane spread for Certification test fuels of 48 to 54 for #1 diesel
fuel and from 42 to 50 for #2 diesel fuel. Testing for this rule performed at
EPA was conducted with 46 cetane number fuel and at SWRI with 45 cetane
number. The average cetane number in Japan in a similar period was 55 and
in Europe about 52. This data was supplied by a Japanese and a European
manufacturer. Under the Clean Air Act (CAA) as amended, CAA § 211(i)
mandates that motor vehicle diesel fuel for sale in the United States on or after
October 1, 1993, have a minimum cetane index of 40 and a maximum sulfur
concentration of 0.05 percent (by weight).
2.2.4.2. Low Sulfur-Certification fuels for on-highway engines are
changing from .2-.5% total sulfur to .02-.05% total sulfur due to CAA § 211(i).
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DRAFT
Lower sulfur content of the fuels reduces the PM emissions and smoke but
does not materially change NOx. The sulfur reduction should reduce corrosion
within the engine, especially when EGR is used, making the use of EGR a
more viable strategy for controlling NOx.
Nonroad engine manufacturers have requested that EPA allow use of
the same low sulfur fuel for certification testing that is mandated by California
so that they can run one certification test for all 50 states. However, until there
is credible evidence that low sulfur fuel will be readily available in commercial
use for nonroad engines, it should not be used for engine certification.
Although most fuel suppliers have the ability to supply low sulfur fuel
to the nonroad market, due to the higher cost of production, low sulfur fuels
are not likely to be made available unless nonroad low sulfur diesel fuel is
mandated. A recent informal survey of the petroleum industry indicated that
some refiners welcomed an extension of the on-highway requirement for low
sulfur fuel to the nonroad market, but that the majority did not. All agreed
that unless low sulfur fuel was mandated for the nonroad market, the higher
sulfur fuel would be continued to be supplied for nonroad use.
2.2.5. Useful Life of Engines
EPA is proposing an expected full useful life period for engines covered
by this proposal of 8,000 hours or 10 years. These values were based on
discussions with nonroad engine manufacturers and analysis of the useful life
of comparable on-highway large CI engines.
Nonroad engine manufacturers have indicated that the great majority of
engines covered by this rule would have a useful life hour range from 6,000 to
10,000 hours, and within one engine family there are likely applications that
will span the entire useful life hour range. This range of useful lives can be
determined in one of two ways. Either useful life is designed into the engine
(i.e., engine components with various life expectancies), or useful life is
dictated by the severity of the engine application. A manufacturer could build
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52 DRAFT
a subset of engines from an engine family with less durable components when
those engines are destined for an application that has an equipment useful life
of less than the engine's normal useful life. This is purely a cost decision and
it would result in two physically different engines in terms of materials or
manufacturing techniques used to make components. Alternatively, a
manufacturer could build all engines with equally durable components, but a
subset of those engines could be installed on a relatively more severe
application which could result in the subset engines having a shorter useful
life. In this second case, manufacturers also indicated that the more severe
applications tend to be those that are not used as many hours per year such
that the useful life years is approximately 10 years whether useful life hours
are 6,000 hours or 10,000 hours.
EPA also analyzed the useful life of comparable on-highway engines. It
was determined that the medium-heavy and heavy-heavy engines were most
similar in durability features to the large nonroad CI engines. Table 2-08
specifies the current on-highway useful lives by engine categories:
Table 2-08
On-Highway Engine Useful Life Definition
On-highway Category
Miles(Kilometers)
Hours @ 33 MPH(44KPH)
Years
Medium-Heavy Diesel
185,000(248,000)
5,550
8
Heavy-Heavy Diesel
290,000(389,000)
8,700
8
On-highway engines have been divided into categories with different
useful lives. This is possible since all applications within a category experience
very similar operating conditions. For example, medium-heavy duty engines
are generally used in trucks and buses with a specified range of load carrying
capability, while heavy-heavy duty engines are only used in trucks with a
higher range of specified load carrying capability. By contrast, nonroad
engines that are identical can end up in a variety of different applications with
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DRAFT
53
varying operational severity. Assuming average on-highway speeds of 33
miles per hour (MPH)[44 kilometers per hour (KPH)], the comparable on-
highway useful lives for medium-heavy and heavy-heavy engines range
between 5,500 and 8,700 hours, and the useful life years in all cases is 8 years.
These results are reasonably comparable to nonroad engine manufacturers
information.
Finally, the length of time an engine actually pollutes before finally
being retired may depend more on how often it is likely to be rebuilt than on
the initial useful life. Nonroad equipment generally outlives its power train
(engine and driveline). The rebuild market has grown more and more
sophisticated in its efforts to fill the demand for rebuilt and remanufactured
engines to put in equipment that is still operational when the original engines
have worn out. The options include engines designed with fully replaceable
cylinder kits (liners and pistons), as well as special machining tools to
resurface cylinder blocks, cylinder heads, and all bearing surfaces. Having
said this, EPA is confident that all engines covered by this proposal are
rebuildable. Thus the amount of total hours or years a particular engines
performs from cradle to grave does not necessarily correspond to its original
useful life, but corresponds more closely to the number of times the engine is
rebuilt before it is permanently retired. Should a 10,000 hour engine be
scrapped after it reaches 10,000 hours while a 6,000 hour engine is rebuilt once
before it is scrapped, the 6,000 hour engine will accumulate an effective
lifetime hours of 2,000 more than the 10,000 hour engine. However, for the
purposes of this rule, EPA is assuming the every engine covered by this
proposal has an equal probability of lasting for an equal total lifetime.
Information available to EPA does not indicate that any subcategory of engines
could inherently be expected to have a greater total life on average than any
other subcategory.
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54 DRAFT
Based on engine manufacturers input and analysis of comparable on-
highway engine information, EPA considered and rejected specifying more
than one useful life category for large nonroad CI engines. Whether engines
within an engine family use different components, or are installed in
equipment of different severity, the fact that any one engine family will likely
span the full range of useful lives (i.e., 6,000 to 10,000 hours) would make it
infeasible to have multiple ranges of useful lives without greatly proliferating
engine families and/or greatly complicating the selection of the worst-case
certification emission demonstration vehicles. Therefore, EPA has decided to
select 8,000 hours or 10 years to represent the average full useful life hours of
a nonroad large CI engine family. EPA is also proposing 6,000 hours or 7
years as the period within which it will select engines to test for in-use
compliance. In this way, even the 6,000 hour engines within an engine family
will never be tested outside their useful life hours.
2.2.6. Market Penetration of NO„ and Smoke Control Technologies
EPA, with input from engine manufacturers, analyzed the likely changes
in engine technology that would be driven by the proposals in this notice. This
was not an easy task considering the diversity of engines and equipment
potentially impacted by this rule. The task was also complicated by a lack of
available information about specific engine sales and the percentage of sales
used in each equipment type. While some manufacturers provided this
information, most were unwilling to do so, citing concerns that leakage of this
information to the public would provide their competitors an unfair advantage
over them in the marketplace. EPA has supplemented the available industry
information with information collected from contractors, state agencies,
marketing brochures and reports, information from test programs, and EPA's
analysis of its own on-highway heavy-duty data base. From these diverse
sources EPA developed a list of assumptions concerning the types of
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DRAFT
55
technology that would be needed to meet the standards proposed in this notice
and the impact on market mix.
2.2.6.1. Industry Input-The general technical assumptions were shared with
engine manufacturers and a number of manufacturers elected to provide
feedback. The respondents were Caterpillar, Cummins, Detroit Diesel, Deutz,
Ford-New Holland, Komatsu-Dresser, Kubota and Yanmar. The assumptions
were adjusted after consideration of industry comments and are shown in
Table 2-09 and discussed below.
Assumption: It Is expected that the market mix of Indirect injection (IDI) engines
to direct injection (Dl) engines will not change as a result of standards proposed In this
rule.
As explained elsewhere in this document, IDI engines produce lower
NOx emissions than DI engines. However, the industry has been rapidly
moving towards DI engines because of superior fuel economy. EPA believes
that some IDI engines that might have been phased out sooner may be kept in
production longer due to this rule. However, since the cost to convert back to
IDI would be much more than applying less expensive technologies to DI
engines, there will be no movement back to IDI. IDI engine families are
approximately 2% of the total number of families now in production. Most
manufacturers agreed with EPA's assessment. However one manufacturer said
it would change one DI family to IDI for the proposed rule and another said it
would change one family to meet the California standards.
Assumption: There are few IDI engines and few naturally-aspirated engines over
175 hp (131 kw). Therefore, only the IDI and naturally-aspirated engines between 50 and
175 hp (37.5 and 131 kw) will be considered In the technology market mix penetration
estimates.
EPA determined that the error caused by ignoring those few IDI and
naturally-aspirated engines above 175 hp (131 kw) will be negligible.
Manufacturers agreed that this was a reasonable approximation.
Assumption: Most naturally-aspirated DI engines will meet the proposed
standards with changes to the fuel system, combustion chamber, and/or swept volume.
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56 DRAFT
Turbocharglng will not be needed since standards are not proposed for HC and PM
emissions.
The standards proposed in this rule are for NOx and smoke only.
Meeting these standards is usually only a matter of retarding the injection
timing, resulting in about a 3% to 5% loss in performance and fuel economy.To
regain this loss the manufacturer may increase injection pressure and change
the injector nozzle tip angle and/or hole size, change the injection timing
strategy, or possibly increase the swept volume of the engine. To regain the
lost performance since the trend has been in that direction anyway, however
adding turbochargers is not the most cost-effective option. While it has not
proposed in this NPRM, manufacturers have asked EPA to adopt standards
conforming to the 1996 MY California rule. If EPA were to adopt California
standards in a final rule, the manufacturer would have to be concerned with
HC and PM emissions. This could entail fitting turbochargers in a few cases.
Four of six manufacturers agreed that turbochargers will not be needed for the
proposed standards. All nine manufacturers that responded felt that some
turbochargers will be required if the California standards were being
considered.
Assumption: Engines covered by this notice will not require low sac Injectors to
meet the proposed standards. However, low sac Injectors are generally necessary to
maintain lower HC emissions.
Low sac injectors affect only HC and do not affect NOx and smoke.
Therefore, they will not be needed for the proposed rule. All manufacturers
agreed on this assumption.
Assumption: Some turbocharged engines will need extra boost and Jacket water
aftercoolers (JWC) to meet the proposed standards.
As in the previous assumption above, turbocharged engines will need
only retarded injection timing and smoke limiters to meet the proposed rule.
Some manufacturers may need to improve aftercoolmg and/or increase boost
to get power and fuel economy back. Should California standards for HC and
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DRAFT
Table 2-09
Responses by Engine Manufacturers to EPA Technology Mix Assumptions
Assumption
Response for the
EPA NOx and Smoke
Proposal
Response for the
CARB 1994 NOx, HC, CO. PM,
and Smoke Standards
agree
disagree
No
Answer
agree
disagree
No
Answer
The market mix of indirect injection (101) engines to direct injection (Dl)
engines will not change as a result of standards proposed in this rule.
5
1
3
4
2
3
There are few 101 engines and few naturally-aspirated engines over 175 hp.
Therefore, only the IDI and naturally-aspirated engines between 50 and 175
hp will be considered in the technology market mix penetration estimates
4
1
4
2
2
5
Most naturally-aspirated Dl engines will meet the proposed standards with
changes to the fuel system, combustion chamber, and/or swept volume.
Turbocharging will not be needed since standards are not proposed for HC,
CO, and PM emissions.
4
2
3
0
9
0
Engines do not require low sac injectors to meet the proposed standards.
5
0
4
0
5
4
Some turbo engines will need extra boost and jacket water aftercoolers
5
1
3
6
0
3
Turtoocharged engines will require smoke limiters Naturally aspirated engines
won't need smoke limiters.
6
1
2
6
1
2
Air-to-air aftercoolers will not be needed.
5
1
3
3
3
3
In line fuel pumps will not be needed
7
0
2
3
3
3
Aftertreatment devices are not necessary.
6
0
3
6
0
3
Manufacturers will choose technologies without loosing power or fuel economy
5
4
0
5
4
0
57
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58
DRAFT
PM emission be considered, some manufacturers will also need to increase the
boost and cooling to improve PM. There was general agreement on this
assumption.
Assumption: Turtoocharged engines will almost always require use of a smoke
llmiter to meet the required smoke standards. Conversely, naturally-aspirated engines
will seldom need a smoke llmiter to meet the proposed standards.
If, for estimating purposes, we assume that all naturally-aspirated
engines have no smoke limiter and all turbocharged engines have a smoke
limiter, the error will be small. Therefore, our technology changes table in
Chapter 2.2.6.2 (Table 2-10) assumes this. There was general agreement on this
assumption.
Assumption: Air-to-air aftercoolers are used in limited high output applications.
It Is expected that no additional use of this technology will be needed for the proposed
rule. However, this technology might be necessary should EPA adopt California's HC
and PM emission standards.
There was general agreement to this assumption for the proposed rule,
although one manufacturer pointed out that air cooled engines could not use
jacket water so any aftercooling must be with air. To meet the California
standards, however, several manufacturers said that they would not rule out
air-to-air aftercoolers although, as described in Chapter 2.2.1.7, their
application to nonroad was more difficult than on-highway.
Assumption: in-line fuel pumps will not be needed to meet the proposed
standards. In-line fuel pumps would be required for those engines with fuel systems
which cannot otherwise meet the Incremental fuel pressure Increases needed If the
California standards for HC and PM emissions were adopted by EPA.
All seven of the manufacturers that responded to this assumption said
that in-line high pressure fuel systems would not be needed for the proposed
rule. Three of the six manufacturers that responded to this assumption said
that in-line pumps would be necessary to meet the California 1996 MY
standards. EPA believes that manufacturers will use higher pressures and
other refinements to existing fuel systems to maintain fuel economy and
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DRAFT 59
performance but not necessarily go to in-line pumps which are more
expensive.
Assumption: Aftertreatment devices will not be necessary to meet the proposed
standards, or the optional standards.
There was total agreement on this assumption.
Assumption: Engine manufacturers will choose a technology mix that not only
ensures the standards are met, but will also maintain the power and fuel economy at
levels that will minimize the Impact of engine changes on equipment.
Five manufacturers agreed with this assumption and four manufacturers
disagreed. Those that disagreed thought that they would not be able to
maintain the fuel economy and performance. Those manufacturers that agreed
included manufacturers of small naturally-aspirated engines which are most
likely to have trouble maintaining fuel economy and performance while
reducing emissions. Engine manufacturers will experience substantial pressure
from the market to minimize increases in fuel consumption and decreases in
performance. EPA has determined that applying available engine technology
can eliminate fuel consumption increases and power losses at the lowest cost
to consumers. That is the cost applied to this regulation in Chapter 3.
In order to use the ten general technical assumptions discussed above to
construct an estimate of the fleet penetration of various technologies caused by
the proposed rules, additional estimates were made based on EPA and
industry supplied data. These estimates were not previewed by engine
manufacturers. These estimates are as follows.
Assumption: Two percent of engines are IDI.
EPA has estimated from published catalog data, that there would be
about 213 engine families and of those four engine families (about 2% of
engine families) would be IDI (see Table D.l in Appendix D). Since no sales
data were available, and based on the assumption that these engines will not
be converted to DI, EPA assumed the same percentage of engines would be
sold as IDI in the 1996 MY.
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60
DRAFT
Assumption: IDI engines will need little more than minor adjustments to meet the
proposed rule.
Four of the five manufacturers that responded to this assumption
agreed. All agreed that the job is easier with IDI than with DI, and the one
that disagreed with the assumption stated that they will change some small DI
engines to IDI. Data collected from tests on one IDI engine provided to EPA
for testing were reported previously in Table 2-05. These data support this
conclusion.
Assumption: About 35% of all engines are naturally-aspirated.
EPA has estimates ranging from 20% to 35% but considered that using
the higher number would correspond to "worst case". This is based on
manufacturers' statements that the naturally-aspirated DI engines would be the
hardest engines to redesign to improve emission performance.
Assumption: About half of the turbocharged large nonroad CI engines are
currently equipped with smoke limlters and about one quarter have jacket water
aftercoolers.
Estimate based on limited data submitted confidentially by
manufacturers and gathered by EPA from market brochures. These are rough
projections.
Assumption: About 35% of current large nonroad CI engines have some sort of
high pressure system, in line pump, unit Injectors, or the like.
Estimate based on data predicting the number of engine families with
various technologies likely to be certified. This is also based on knowledge of
the percentage of manufacturers that are currently using in-line and unit
injector systems.
Assumption: About 5% of engines already employ low or no sac Injectors and
that will double by the 1996 MY without any emissions regulations.
Estimate based on confidential information on available technology as
projected by a limited number of manufacturers.
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61
2.2.6.2. EPA Proposal-Using the above assumptions, Table 2-10 represents
the change in technology penetration after full implementation of the proposed
rule. The first column in the table titled, "1996 MY with No Standards" is
EPA's best estimate from the data available of the percentage of the various
Table 2-10
Effect of Proposed Standards on Technology Mix
Technology
Market
Percentages
in 1996 MY with
no standard
1996 MY Market
Percentages With
EPA Proposed
Standards
Additve %
Change due to
EPA Proposed
Standards
No Changes
—
2%
2%
Retard timing
0%
98%
98%
Indirect injection
2%
2%
0%
Direct injection
98%
98%
0%
Low sac injectors
10%
10%
0%
Improvements in fuel pumps and nozzles
0%
20%
20%
High pressure pumps or unit injectors
35%
35%
0%
Naturally-aspirated
35%
30%
-5%
Turtxicharged
65%
70%
5%'
JWC aftercooled
15%
25%
10%
Air to air coolers
5%
5%
0%
Smoke limiter
30%
70%
40%
" With averaging, banking and trading, tPA expects this number will be U%.
injectors and about 35% use either unit injectors or inline pumps with high
maximum injection pressure. About 35% are still naturally-aspirated leavmg
about 65% turbocharged with about 15% jacket water aftercooled and 5% Air-
to-Air aftercooled.
The third column is the projected change in each technology listed due to
adoption of the proposed standards. EPA projects that when the standards
have been fully implemented, about 2% of the engines will experience no
change since all IDI engines (i.e., 2% of all engines) will meet the proposed
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DRAFT
regulations without timing retard. The remaining 98% of the engines will have
had their timing retarded. The mix of IDI and DI will not change significantly.
Although one manufacturer said they would change one engine family from
DI to IDI it was not enough to change the rounded percentage calculation.
Low sac injectors are not a factor for NOx and smoke and should not change
but EPA expects that 20% of the engines will need improvements in the fuel
system, such as higher pressures, improved timing control and better spray
patterns. No engine will need to go to the high pressures associated with in-
line pumps or unit injectors. Without averaging, banking and trading,
naturally-aspirated engines should decline by 5% with a corresponding
increase in turbocharged engines to 70 % of production, with jacket water
aftercooling increasing from 10% to 25% of the total and no change in air-to-air
aftercooling. Since the proposed averaging, banking and trading program
provides substantial flexibility for manufacturers to average small naturally-
aspirated engines against larger turbocharged engines, EPA believes that no
additional turbochargers will be needed to meet the proposed rule. All
turbochargers need smoke limiters so they change from 30% to 70%.
2.2.6.3. California 1994 Model Year Standards-For comparison EPA looked at the
technology mix required should EPA reconsider adopting the California
standards of 1.0 g/bhp-hr HC, 8.5 g/bhp-hr CO, and 0.4 g/bhp-hr PM. Table
2-11 was compiled from EPA's assessment of the same EPA and industry
supplied data. The difference in this table and Table 2-10 rises out of the
emission trade-off that occurs between NOx and PM emissions, and to a lesser
extent, between NOx and HC emissions. Basically, the technology most
effective at NOx reduction tends to increase HC and/or PM emissions. When
reductions in one pollutant cause increases in another pollutant, the effect is
termed an "emission trade-off." When technology is applied to reduce NOx
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63
emission produces an emission tradeoff in other pollutants, additional
technology must be applied to offset the increase in PM or HC emissions.
Table 2-11
Effect of the 1996 MY California
HC, CO, NOx, and PM Standards
on Technology Mix
Technology
Market
Percentages
in 1996 MY With
No Standard
Market
Percentages due to
California 1996 MY
Standard
Percentage
Change due to
California 1996
MY Standard
Retard timing
0%
97%
97%
Indirect injection
2%
3%
1%
Direct injection
98%
97%
-1%
Low sac injectors
10%
60%
50%
Improvements in fuel pumps and nozzles
0%
15%
15%
High pressure pumps or unit injectors
35%
85%
50%
Naturally-Aspirated
35%
20%
-15%
Turtxichargers
65%
80%
15%
JWC Aftercooler
15%
35%
20%
Air-to-air aftercoolers
5%
10%
5%
Smoke limiters
30%
80%
50%
This table shows that IDI engines will increase from 2% to 3% leaving 97%
DI and 97% needing timing retard. Low sac injectors are important for HC
control and 50% of engines will need to have them added for a total of 60%.
About 15% of engines will be able to meet the California standards with rotary
pump improvements but 50% will need to add high pressure pumps to control
the PM emission. Turbocharged engines will increase about 15% to a total of
80% with a corresponding decline in naturally-aspirated engines. Jacket water
aftercooling will increase by 20% to a total of 35% and Air-to-Air aftercoolers
will double to 10% of production. Manufacturers have indicated that these
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64
DRAFT
changes are necessary to control NOx and PM emissions simultaneously.
Smoke limiters will again be necessary on all turbocharged engines, including
the additional new conversions to turbocharging, for a total of 80%.
2.3. Impact on Equipment
The needs of nonroad equipment users are somewhat different than
on-highway users. Fuel economy is not as important because of the lower cost
of fuel (no road taxes), although it is important that a given piece of
equipment operate for a full shift without refueling. Power to weight ratio is
less important for some types of equipment (tractors). Durability in a more
hostile environment is more important, especially in those areas where service
facilities are less available. The ability to survive and perform well in a dusty
environment is important to nonroad users since they often operate in such an
environment. Finally, large nonroad CI engines often have a flatter torque
curve than on-highway engines due to the greater lugging requirements
experienced in many nonroad applications.
2.3.1. Reason for Concern
Equipment manufacturers provided EPA with their assessment as to the
impact of proposed regulations on equipment manufacturing costs. Their
responses were compiled in three categories and reported in Table 2-12. The
three categories were impacts on packaging, power train, and operation and
maintenance costs.
Question: What Is the Impact of the regulation on powertrain design?
Of the 15 manufacturers that responded to the enquiry, nine expressed
general concern and lack of knowledge as to what would happen. Two
manufacturers thought that there would be no major changes to drivetrain,
and four thought that there would be major changes. Concerns were centered
around loss of power and lower speeds. One manufacturer claimed the demise
of direct drive although another division of the same company foresaw no
major changes.
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DRAFT
Table 2-12
Equipment Manufacturers' Responses to EPA Questions
Question
major
minor
No
Answer
Comments
1. What is the impact
of regulation on power
train design?
4
2
9
Poor low speed response can be
sacrificed in some applications
(no reason to modify power train).
Hydraulic pump and
transmissions changes may be
needed to overcome power &
speed losses.
2. What is the impact
of regulation on
packaging design?
1
1
3
Increased cooling may be
necessary and would be limited
by design constraints.
Sheet metal changes necessary
to accommodate engine changes.
A larger fuel tank is needed for
several applications.
Noise reduction modifications may
be necessary.
3 What is the impact
of regulation on
operation/maintenance
requirements?
8
2
5
These responses seem to be
based on what their engine
suppliers have told them:
less reliable, less durable, loss in
power, additional maintenance
and wear, and performance
degradation.
Two of 15 OEM's aren't expecting
these problems.
Question: What is the impact of the regulation on packaging?
Eleven manufacturers claimed major changes, three were generally
concerned and lacked the necessary information to respond, and one thought
there would be no major changes. Major concerns were sheet metal, radiator
size, and fuel tank size. This was based on equipment manufacturers
expectation that the cost of a 3% to 5% increase in fuel consumption and a 3f
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DRAFT
to 5% increase in heat rejection to the radiator from the unregulated nonroad
engine design would be passed on by the engine manufacturer. Since this is
not the most cost-effective approach, EPA does not expect it will happen (see
EPA assessment in Chapter 2.3.2).
Question: What Is the impact of the regulation on operation/maintenance?
Five manufacturers cited the loss of power or performance degradation, 4
were concerned with increased fuel consumption of about 5%, and 2 cited
increased maintenance or loss of reliability. On the other hand one thought
there would be no loss of performance or durability and one thought there
would be no effect on maintenance, reliability, durability, or serviceability. Five
did not respond.
2.3.2. EPA Assessment
EPA has determined that the engine changes required to meet the
standards proposed in this notice should have a minimal impact on
equipment. Equipment manufacturers were asked to determine what the
various engine changes, as explained by their suppliers, would do to their
equipment designs. Table 2-12 shows the results of the survey. Fifteen
manufacturers replied to one or more of the questions. Of the responders, four
were part of large integrated companies. It appeared that all but one
responded to the preliminary information received from their engine suppliers
about the 1996 California rule.
Equipment manufacturers generally stated that they did not know what
engine manufacturers would have to do to comply with emission standards,
and based on that, what redesign would be necessary to the equipment itself.
Many of these responses were not quantified, but instead used qualitative
statements such as "expensive changes" and "increased fuel consumption."
Many of the responses presented the worst-case assumptions. For example,
one manufacturer said that there would be a 20% loss in power, which seemed
excessively high in light of other test data showing 1 to 5 percent maximum
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DRAFT 67
power loss before using restorative technologies. Based on input from engine
manufacturers with respect to what technologies will actually be needed to
meet the proposed standards, EPA has determined that all necessary engine
design changes will be internal engine changes, and will have little impact on
equipment design. Equipment manufacturers have been asked to provide
further evidence to EPA to substantiate their concerns with respect to the
impact of changes in engine design on equipment design.
Most of the equipment manufacturers responses were made for the full set
of California standards and not for the proposed rule. Comparing Tables 2-10
and 2-11, it is clear that some engines designed to California's rule may require
increased use of more invasive technologies to meet HC and PM emission
standards (such as the addition of turbochargers on naturally-aspirated
engines) than engines built to meet EPA's proposed NOx and smoke only rule.
EPA has not assessed the likely cost impact of adopting the California HC, CO,
and PM emission standards. However, EPA believes that considering
additional emission standard requirements could only make the program more
complex. Since equipment manufacturers did assume engines designed for
California, it is likely they overestimated the potential impacts of EPA's more
limited proposal on equipment design.
EPA holds that changes to equipment should be minor, centered around
sheet metal and cooling. The required engine changes will be internal in most
cases. In all cases, the technologies predicted to be necessary in these engines
such as fuel injection retard, fuel system upgrades, and combustion chamber
upgrades, would not substantially change the engine package. Equipment
manufacturers have not provided evidence to support their claims that EPA's
proposal will cause significant equipment impacts. By contrast, engine
manufacturers and EPA have provided evidence and test data summarized in
this document showing that the impact of changes on power, packaging, and
operation and maintenance will be minimal.
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DRAFT
EPA has determined that the technologies necessary to restore engine
performance and fuel economy are available such that the changes will have
minimal impact on the equipment manufacturer. As seen in Chapter 2.4.1.,
once fuel injection timing is retarded sufficiently to meet the proposed NOx
standards, the remaining technologies projected to be needed under this
proposal are needed to restore or maintain performance lost (i.e., restore fuel
economy and power) should all reduction be carried out through fuel injection
timing retardation. The technological tools available to manufacturers, as
discussed in Chapter 2.4.1., are various combinations of fuel pump and nozzle
changes, combustion chamber changes, engine derating, turbocharger boost
increases, aftercooler efficiency gains or new use, and smoke limiters to reduce
smoke levels. As discussed in Chapter 2.2.1., these are internal engine
modifications meant to minimize impacts on performance and engine
packaging. In Chapter 2.2.3., EPA discussed those technologies that are
infeasible based on larger impact on equipment and longer development
leadtime requirements. EPA has determined that the projected engine changes
discussed in Chapter 2.2.1. are feasible within the proposed leadtime and can
be implemented cost-effectively (see also Chapter 3.1.1.). It is likely that the
equipment impacts feared by equipment manufacturers would require
substantially longer leadtimes. Engine manufacturers have stated they are
responsive to their customers' (the equipment manufacturers') needs and
engine manufacturers' responses to EPA's technical assumptions in Chapter
2.2.6.1. demonstrate that they are expecting to use the technologies identified
by EPA as necessary to minimize equipment impacts.
Engine packaging would only be impacted by physical dimension changes
to the engines. Of the potential technologies available to meet the
requirements of this rule, only use of turbochargers and air-to-air aftercoolers
will substantially change external engine dimensions. As summarized in Table
2-10 of Chapter 2.2.6.2., EPA projects no significant new use of air-to-air
-------
DRAFT
69
aftercoolers and, with averaging, banking, and trading, no significant new use
of turbochargers to comply with this proposed rule. All remaining changes
projected in Table 2-10 have little impact on external engine dimensions, and
thus little to no impact on equipment package design.
Finally, EPA's review of a number of available on-highway engine service
manuals revealed no significant difference in required service between engines
that are currently built with the various component packages projected to be
needed to meet the proposed standards (see Table 2-10). The full range of
technologies expected to be used are current production components with a
long history of use both in on-highway and nonroad applications. The EPA
review uncovered no unique operation or maintenance requirement for any
expected changes in technology caused by this proposal. Therefore, EPA has
concluded there will be no significant impact caused by changes in operation
and maintenance requirements in response to this rule.
2.4. Impact on Performance
At the proposed NOx and smoke levels, effects on performance will be
minimal. This section discusses briefly EPA's assessment of the effects of this
proposal on fuel economy, power, noise and safety.
2.4.1. Fuel Economy and Power
EPA recognizes that the first step manufacturers would take to reduce NOx
emission would be to retard fuel injection timing. An EPA study has shown
that retarding injection timing by 4 to 7 degrees is required to allow the
current production nonroad engine to meet the proposed NOx emission
standard. However, as seen in Table 2-13, taken by itself fuel injection retard
could result in a 1 to 5 percent increase in fuel consumption and a similar loss
in power. While the nonroad market is less sensitive to changes in fuel
consumption, it is very sensitive to any losses in power large enough to
require power train changes or increases in fuel consumption large enough to
cause an equipment application to be fueled more than once during a full
-------
70 DRAFT
working shift. Faced with a fuel consumption increase and power loss of 1 to
5 percent, the equipment manufacturer must decide whether its power train
has enough flexibility and the fuel tank has sufficient excess capacity to
accommodate the higher fuel consumption rate and still work an entire shift,
or whether the equipment manufacturer should shop for an engine
manufacturer that has applied the engine technology necessary to maintain the
engine's pre-regulation fuel economy and power. Most manufacturers have
designed their fuel tanks with sufficient excess capacity to accommodate small
increases in fuel consumption. However, EPA has concluded that the amount
of fuel economy loss and power loss realized under the proposed standards
can be recovered within a reasonably short leadtime and at a reasonably low
cost by applying engine technologies discussed in Chapter 2.2.1. Some
examples of these technologies are as follows.
• Increasing the air/fuel ratio by increasing turbo boost, aftercooling,
or derating will in many cases improve fuel economy and
performance at any particular emission level.
• Increasing injection pressure will atomize the fuel better, get the
main combustion over quicker, which will again result in
improvements in fuel economy and performance at any particular
emission level.
• Adding fuel injection control will allow more efficient fuel injection
timing for all loads and speeds. Calibrators can then optimize
emissions and fuel economy.
Engine manufacturers have indicated (see Chapter 2.2.6.1.) that they will
use combinations of these technologies to minimize the performance losses
associated with meeting the proposed standards. Faced with the options
described above, equipment manufacturers will, in most cases, choose to pay
the small increase in per engine cost required to maintain an engine's pre-
regulation fuel economy to avoid a potentially long delay in leadtime and
higher cost to redesign their equipment to accommodate fuel economy or
power losses accompanying low cost NOx emission reduction strategies.
-------
DRAFT 71
To regain the loss of power and fuel economy a manufacturer would add
some combination of technologies. For naturally-aspirated engines, the options
currently identified by EPA and industry are a moderate increase in injection
pressure, mechanical fuel injection timing control, larger displacements, and
redesigned combustion chambers. For turbocharged engines, the options are
higher boost pressures, air to water aftercooling, moderate increase in injection
pressure, mechanical fuel injection timing control, and redesigned combustion
chambers.
If the NOx standard had been set lower than the 6.9 g/bhp-hr (9.2 g/kw-
hr) level additional, more expensive and invasive technology would have to be
used. Among these are technologies such as high pressure in-line pumps or
unit injectors, turbochargers added to NA engines, air to air aftercoolers in
place of air to water, and electronic fuel control.
EPA history with on-highway engines shows that the proposed standards
can be met without impacting fuel economy or engine power. While the
impact of specific technologies used to lower emissions can be to reduce fuel
economy or power, in the on-highway market manufacturers have historically
used a combination of technologies that not only maintain the fuel economy
and power of an engine redesigned to meet emission requirements, but have
actually improved fuel economy and increased power.
EPA analyzed the impact of increasingly stringent emission standards on
fuel consumption and power by comparing fuel consumption and power for
engine models over a number of model years when emission standards were
changing. Table 2-14 shows the percent change in emissions, fuel economy,
and power from on-highway engines between the 1988 and the 1991 model
year.
-------
72
DRAFT
Table 2-13
Impact of Injection Timing Retard on BSFC* and Power
Manufacturer
and
Test Number
Performance
Parameter
Baseline
Level
Degree
Retard
Retarded
Level
%
Difference
John Deere
A-3
Power
(HP)
(kw)
141
189
7
134
180
-5%
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0 348
158
0 363
221
4%
John Deere
A-4
Power
(hp)
(kw)
141
189
7
137
184
-3%
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0 348
158
0.352
214
3%
Cummins
B-3
Power
(hp)
(kw)
105
141
4
100
74 6
-5%
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0.372
227
0.378
230
2%
Detroit Diesel
D-1
Power
(hp)
(kw)
450
603
7
-
--
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0.361
220
0 372
227
3%
Detroit Diesel
D-3
Power
(hp)
(kw)
450
603
9
-
--
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0.361
220
0.379
230
5%
Ford New Holland
F-3
Power
(hp)
(kw)
130
174
5
131
176
1 %
BSFC
(Ibs/bhp-hr)
(g/kw-hr)
0.337
205
0.314
191
-7%
Note: Detroit uiesei bsi-u is at maximum power ana tne otners are over tne B-moae cycle.
particulate matter(PM) decreased 51%, smoke decreased about 45%. During
this period of substantial improvement in emission performance,
manufacturers also managed to realize a specific power output increase of 4%
and a fuel consumption decrease of about 1%.
-------
DRAFT
73
Table 2-14
Average On-Highway Emission Factors
Performance
Parameter
1988
1991
%
Change
HC (g/bhp-hr)
(g/kw-hr)
066
0 88
0 37
0 49
- 44 %
CO (g/bhp-hr)
(g/kw-hr)
2 86
3 83
2 04
2.73
- 29 %
NO, (g/bhp-hr)
(g/kw-hr)
7.13
9 55
4 49
6.01
- 37 %
PM (g/bhp-hr)
(g/kw-hr)
0.45
060
0.22
0 29
- 51 %
Smoke
(% Opacity)
Acceleration
12.1
7
- 42 %
Lug
65
2.9
- 55 %
Peak Load
21.4
12.3
- 43 %
BSFC (Ibs/bhp-hr)
(g/kw-hr)
0.359
219
0 355
216
-1 %
Power hp/in3
kw/1
0.476
21.7
0.494
22.5
4%
These on-highway certification data demonstrate that it is technologically
possible, even probable, that manufacturers will design engines that make fuel
efficiency gains even as they are required to meet tighter, more demanding
emission standards.
2.4.2. Noise and Safety
No hard test data has been gathered on either noise or safety but based on
the accumulated knowledge and experience of the EPA staff the following
conclusions can be drawn.
2.4.2.1. Noise-Due to the retarded fuel injection timing, the detonation,
which is the noise heard as the typical diesel "knock" will be reduced. The later
timing might also increase the exhaust noise slightly but exhaust is quite easily
muffled, detonation is not.
-------
74
DRAFT
Heat rejection to the cooling water will be increased if fuel economy is
allowed to decrease. In that case, fan noise will tend to increase if larger fans
are used or if fans are run at higher tip speeds. However, EPA has
determined, through analysis of data and input from manufacturers discussed
previously, that technologies will be applied to engines to restore the efficiency
losses associated with fuel injection timing retard. Therefore, heat rejection
changes will be minimized, and its impact on noise will likely be insignificant.
2.4.2.2. Safety-There are no apparent safety issues attached to this rule.
Manufacturers will likely use only proven technology that is currently used on
on-highway and nonroad engines. This proposal presents no apparent new
safety issues associated with use of these technical solutions.
2.5. Feasible Emission Standards
EPA has determined that the proposed NOx emission and smoke standards
are technologically feasible and can be achieved through the application of
technologies that will be available within the allotted leadtime for reasonable
cost. There are a broad range of technologies currently available for on-
highway engine use that'are capable of ensuring reductions well below the
proposed standards as demonstrated by the range and average of NOx
emission and smoke levels for on-highway heavy-duty diesel engine families
Table 2-15
Fleet NOx Emission and Smoke Statistics for
1990 Model Year On-Highway Heavy-Duty Diesel
Engine Family Emission Data Engines
NOx
ACC
LUG
PEAK
(g/bhp-hr)
(percent)
(percent)
(percent)
AVERAGE
5.2
12
6
20
STD DEV.
.5
4
3
8
MAX
6
20
14
45
MIN
3.5
2
1
3
STANDARD
6
20
15
50
-------
DRAFT
75
certified for the 1990 model year as shown in Table 2-15. EPA has determined
that a subset of these technologies (discussed below and described in Chapter
2.2.1.) can be effectively used to meet the requirements of this proposal and are
compatible with nonroad applications. EPA believes that these standards can
be met without substantial engine redesign, and thus can be implemented by
the proposed model years.
2.5.1. Effect of Available Technologies on Emissions and Performance
Chapter 2.2.1. describes the technologies that EPA and industry have
determined will be used and will be capable of meeting the proposed
standards. These technologies include fuel injection base timing changes, fuel
injection pump improvements such as variable injection timing and increased
injection pressures, fuel injection nozzle modifications, combustion chamber
modifications, air to water aftercooler improvements and additions,
turbocharger improvements, and increased application and optimization of
smoke limiters. These technologies will allow all engines covered by this
proposal to meet the proposed standards while substantially maintaining fuel
economy and power (see also Chapter 2.4.1.). Additionally, these technologies
are not impeded by certain constraints specific to nonroad engines that affect
the feasibility of using other technologies, as will be discussed in Chapter 2 6.
An EPA test program of a number of production nonroad engines
demonstrated that the average large nonroad CI engine can be brought into
compliance with the proposed NOx emission standard by retarding injection
timing alone. For the NOx levels required by this proposal, EPA observed that
retarding injection timing causes small increases in HC and PM emissions and
small increases in brake specific fuel consumption (BSFC) and losses in brake
horsepower (BHP). However, EPA believes these impacts are manageable
because they can be offset by use of various combinations of technologies as
discussed in Chapter 2.4.1.. For example, variable fuel injection timing and
increased fuel injection pressure improve atomization and timing optimization,
thus providing more fuel injection base timing flexibility to recover fuel
-------
76 DRAFT
efficiency and power losses without losing the NOx reduction benefit. Data
from this test program, listed in Table C-01 of Appendix C, are summarized in
Table 2-16.
The test program results demonstrate that the amount of NOx emission
reduction per degree of fuel injection timing retard as tabulated in the column
titled "Emission Change per Degree Retard - NOx 8-Mode," was consistent for
most of the current production nonroad engines tested in this program. These
were engines with base NOx emission levels around 9 to 12 g/bhp-hr (12.1 to
16.1 g/kw-hr). At least one manufacturer indicated that this observation is
consistent with its observations as well.6 NOx emission is reduced by
approximately 0.8 g/bhp-hr (1.0 g/kw-hr) for each degree the fuel injection
timing is retarded.
Generally, a manufacturer would be capable of calibrating the fuel injection
timing to meet its NOx emission target level while minimizing BSFC increase
and power loss. Averaging all the BSFC and Power percent change data, then
averaging them again for only those engines that were reduced to just above
6.0 g/bhp-hr (8.0 g/kw-hr) NOx, a reasonable range of expected BSFC increase
and power loss expected under this rule can be estimated. The average fuel
consumption increase would be approximately 2 - 3 % and the average power
loss would be approximately 3-4 %. These losses in efficiency can be
substantially offset using the technologies listed previously.
As discussed in Chapter 2.4., EPA believes these technologies will be
adequate to offset any fuel consumption increases or power losses caused by
this rule. Design modifications to fuel pumps and nozzles to increase
pressure, introduce variable timing, and affect spray pattern and atomization
all act to not only reduce NOx emission at lower levels of injection timing
retard, but also act to encourage more complete combustion, thus increasing
engine efficiency (i.e., reducing fuel consumption and increasing power) while
6 Meeting with Engine Manufacturer Association members on October 28, 1992
-------
DRAFT
77
Table 2-16
Effect of Fuel Injection Timing Retardation on Emissions
Engine
Manufacturer
and
Test Number
NOx Level at
Degree of Retardation
Emission Change
per Degree Retard
Percent
Change
0°
4°
7°
9°
NOx
8-
mode
HC
FTP
PM
FTP
BSFC
•
power
John
Deere
A-3
g/bhp-hp
11.8
6.3
-08
0.1
0.08
+4%
-5%
g/kw-hr
15.8
8.4
-1.0
0.1
0.1
John
Deere
A-4
g/bhp-hr
11.8
71
-0.7
0
0 06
+3%
•3%
g/kw-hr
15.8
9.1
-0.9
008
Detroit
Diesel
D-1
g/bhp-hr
12.1
70
-0.7
0
0
+3%
—
g/kw-hr
162
9.3
-09
0 02
Detroit
Diesel
D-3
g/bhp-hr
12.1
5.8
-0.7
0
0.03
+5%
...
g/kw-hr
162
77
-09
0.04
Ford New
Holland
F-3
g/bhp-hr
9.3
5.9
-08
0.4
0.1
•7%
+1%
g/kw-hr
12.4
7.9
-1.0
0.5
0.1
Cummins
P 4
g/bhp-hr
11.1
5.6
•1.4
0 07
0
+2%
-5%
Ov
g/kw-hr
14.8
7.5
-1.8
0 09
0
Average
of All Data
g/bhp-hr
11.4
5.8
67
5.8
-0.9
0.10
0 05
+2%
-3%
g/kw-hr
15 2
78
89
78
-1.1
0.12
0 06
Average of
*60 NOy
g/bhp-hr
11.9
6.7
•0.7
003
0.05
+3%
•4 0%
Engines
Hemrte
g/kw-hr
15.9
8.9
•0.9
0 04
0 07
maximum power.
also reducing HC and PM emissions. Modifications to combustion chamber
design that increase displacement, which allows derating, or that change the
shape of the combustion chamber, which impacts complete combustion, can
-------
78 DRAFT
also be optimized to improve complete combustion and increase engine
efficiency. Additional modifications are also available to those engines that are
currently turbocharged. Modifications that increase intake air density such as
increased turbocharger boost or new or more efficient air to water aftercooling
can increase efficiency.
Increases in HC and/or PM emissions are also common as fuel injection
timing is retarded on any particular large nonroad CI engine. However, Table
2-16 shows that PM and HC emission increases between 4 and 9 degrees of
retard that are small enough to be restored using the technologies described
above. For example, since the fuel injection system modifications expected
would improve atomization, the time needed to complete combustion would
be shortened, thus reducing HC and PM emissions (see Chapter 2.2.1). This is
consistent with the technical literature (an example of which is pictured in
Chapter 2.6, Figure 2-02) showing that NOx to HC and NOx to PM emission
trade-off is reasonably flat down to approximately a 6 to 7 g/bhp-hr (8 to 9.3
g/kw-hr) NOx level of control, below which the trade-off emissions increase
exponentially.(12,13,14) The remainder of this section discusses information on
prototype engines which exemplify how these emission trade-offs can be
mitigated.
John Deere provided EPA with one early prototype engine and one current
nonroad production engine from each of two engine models. While
these prototypes were not yet optimized, they do provide the best available
approximation to the technologies from the list of feasible approaches
discussed above.7 For each of the two engine sets, Table 2-17 shows changes
7
The 140 hp engine uses a somewhat low-efficiency air-to-air aftercooler that is not on the list However, this
engine also uses a range of technologies from the list of feasible approaches The 75 hp engine only uses technologies
on the list
-------
DRAFT 79
in emissions, fuel consumption at maximum power8, and maximum
horsepower due to modifications made to the prototype engine compared to
the comparable production engine.
Results of Table 2-17 show that the proposed NOx and smoke standards
can be reasonably achieved without causing significant increases in other
pollutants or significant losses in fuel efficiency or power. The prototypes met
all the standards proposed in this notice while showing improvements in HC
and PM emissions. HC emissions increased in one case. Further optimization
could reduce or eliminate this HC emission trade-off. The improvements,
observed in HC and PM emissions measured over the transient FTP, provide a
concrete example of how the same technologies can be used to both offset fuel
efficiency and power losses, and directionally reduce the negative impact of
fuel injection timing retard on HC and PM emissions. This is consistent with
Table 2-17
Impact of John Deere Prototype Modification on HC, PM, BSFC and Power
Engine
Modification
Set
Number
Power
Baseline
(BL)
and
Prototype
(P)
NOx level
Prototype
Smoke
(Acceleraton=A
Lug Mode=L
Peak Load=P)
Percent Change
Between
Baseline Engine
and
Prototype Engine
BL
P
A
L
P
NOx
8-
mode
HC
FTP
PM
FTP
BSFC
@
Max.
Power
Max
Power
1
g/bhp-tir
140 hp
11.8
6.1
-•
••
--
-48 %
-15 %
-17%
-2%
9%
g/kw-hr
104 kw
158
82
2
g/bhp-hr
75 hp
7.2
6.1
3%
4%
4%
-15%
+20 %
-5%
1 %
1 %
g/kw-hr
56 kw
9.7
8.2
£
Since the prototype engines are not yet optimized, EPA chose to use the BSFC at maximum power ns a rru>rv
accurate indication of potential fuel efficiency gains BSFC over the test cycle is useful once the engine lw- Iwn
optimized over the entire operating range
-------
80 DRAFT
current understanding of each of these technologies, as discussed in Chapter
2.2.1, that the specific technologies EPA expects to see being used to meet the
requirements of this proposal often cause general efficiency gains that show up
simultaneously as relatively little change in BSFC and power, and reductions
in HC, CO, NOx, and PM emissions. Refer back to Chapter 2.2.1 for specific
discussion of the general trends of specific technologies.
These prototype results show NOx levels of 6.1 g/bhp-hr (8.1 g/kw-hr),
well below the 6.9 g/bhp-hr (9.2 g/kw-hr) standard, and smoke levels of 3%
opacity during acceleration mode, 4% during lug mode, and 4% during peaks
in either mode, all well below the 20% acceleration, 15% lug, and 50% peak
standards proposed. These prototype results, as well as the information in this
document, demonstrate that the proposed standards can be achieved with
technologies that are feasible within the constraints of this rule and without
causing significant negative impacts on HC, PM, BSFC, or power. As
discussed in Chapter 2.3.2, applying these technologies to the engine will likely
be the most timely and cost-effective manner to offset the impact of a NOx and
smoke standard on other pollutants and on fuel efficiency and power.
2.5.2. Leadtlme and Cost
The technologies used on the prototype engines characterized in Table 2-17
are the closest approximation available to the technologies that can be applied
within the proposed timeline and at low cost. Engines at or above 175 hp (131
kw) require the shortest leadtime. These engines are comparable to current
on-highway designs and will require the least additional redesign work.
Further, manufacturers have already started developing these larger engine
designs to meet standards proposed in California for the 1996 model year for
farm and construction engines at or above 175 hp (131 kw). EPA's proposed
implementation date of the 1996 model year is thus reasonable and feasible for
the engine at or above 175 hp (131 kw). As discussed below, Table 2-17
demonstrates that the same range of technologies that allow engines with
horsepower at or above 175 (131 kw) to meet the proposed NOx standard will
-------
DRAFT 81
also allow smaller engines to meet that standard. Therefore, in order to ensure
that smaller engines meet the proposed NOx standard, manufacturers must
apply the available technologies to specific engine families with horsepower
less than 175 (131 kw). EPA believes that additional leadtime of one year
(implementation in the 1997 model year) for engines with horsepower from
100 to 175 (74.6 to 131 kw), and additional leadtime of two years
(implementation in the 1998 model year) for engines less than 100 hp (74.6 kw)
is appropriate in order for manufacturers to make design changes to these
smaller engines to incorporate the necessary technology.
2.5.3. Effect on Engines Below 175 Horsepower
Manufacturers have expressed concern that engines covered by this
proposal that are less than 175 hp (131 kw) and especially those engines less
than 100 hp (74.6 kw) would not be capable of meeting the proposed
standards. Manufacturers have not presented data to support this concern
because their research resources are focused on 175 hp (131 kw) and above
engines to meet requirements of the California regulations for off-road farm
and construction engines greater than or equal to 175 hp (131 kw) that go into
effect in the 1996 model year. As expressed earlier, EPA is proposing to allow
one additional year of leadtime for engines covered by this proposal that are
less than 175 hp (131 kw) and two additional year for engines less than 100 hp
(74.6 kw). This additional leadtime should provide time to develop these
smaller engines to meet the same standards the industry is prepared to meet
with larger engines.
EPA studies indicate that the NOx emission and smoke levels of current
production smaller nonroad engines produce comparable emissions to those
for larger nonroad engines. EPA analyzed the emission test data comparing
emissions from engines over and under 100 hp (74.6 kw). The results of this
analysis are summarized in Table 2-18.
Table 2-18 is split in two parts, engines at or under lOOhp (74.6kw) on top
and engines over lOOhp (74.6kw) on the bottom. All these engines were
-------
82 DRAFT
supplied by their respective manufacturers, through EMA, as representative of
current production. Based on these data, EPA concludes that current
production small engines do not generate more NOx and smoke than do large
engines, at least down to 50hp (37.3kw).
Table 2-18
Current Production Nonroad Engines
8-Mode Emission Test Results
Engine
Manufacturer &
Combustion
Chamber Type
Power
g/bhp-hr
(g/kw-hr)
smoke % opacity
HC
CO
NO,
PM
Accel
Lug
Peak
50 ¦ 100 hp (37.3-74.6 kw) engines tested
Teledyne IDI
hp
66
019
2.57
54
1
12
21
22
kw
50
0.25
3.45
7.2
1.34
Confidential Dl
hp
51
0.92
3.94
12.5
0.44
kw
38
1.23
5.28
16.7
0 59
Ford NH Dl
hp
53
0.80
3.00
7.40
0 46
kw
39 5
1.07
4.02
9.9
0.62
Deutz Dl
hp
56
1.36
2.62
6.9
0.36
kw
39.5
1 74
3.51
92
0.48
Ford NH Dl
hp
67
0.98
8.80
7.10
064
•
kw
50
1.31
11.8
9.5
0.86
Ford NH Dl
hp
69
1.20
4.00
9.00
0.39
kw
51.5
1.61
5.36
12.0
0.52
John Deere Dl
hp
76
064
3.50
724
0.59
12
23
24
kw
56.7
0.86
282
9.7
0.64
average
hp
62
0.87
4.06
7 93
0 54
12
22
23
kw
46.2
1.17
5.44
10.6
0 72
100 + hp (74.6 -i- kw) engines tested
Cummins Dl
hp
105
0 75
2.20
11.10
0.41
25
6
54
kw
78.3
101
2.95
14.8
0 55
-------
DRAFT
83
Table 2-18
(conL)
Ford NH Dl
hp
130
0.70
5 58
9.27
0 96
11
26
27
kw
96 9
0.94
7.48
12.4
1 29
John Deere Dl
hp
141
0.43
3.14
11.76
0.42
13
9
22
kw
105
0 58
4 21
15.7
0.56
Caterpillar Dl
hp
288
1 14
1.44
6.5
0.18
31
3
60
kw
215
1 53
1 93
8.7
0.24
Detroit Diesel Dl
hp
450
0.36
0 80
121
0.12
20
2
38
kw
336
048
107
16.2
016
average
hp
223
068
2.63
10.1
0.42
20
9
40
kw
166
0.91
3.53
13.5
0.56
EPA also has evidence that the same level of fuel injection timing retard
will generally bring these smaller engines into compliance. The same
technologies used for the larger engines can be used on these smaller engines
to effectively restore efficiency loss. This was demonstrated by the results
presented in Table 2-17 that show engines less than 175 hp (131 kw) are
capable of meeting the proposed standards using the technologies listed in this
discussion. One of the prototype engines listed in Table 2-17 is less than 175
hp (131 kw) while the other is less than 100 hp (74.6 kw). The technologies
used on these engines are the best available approximation of those feasible
technologies listed earlier in this discussion. While some increase in HC
occurred in one of the not yet
optimized prototype engines, HC and PM emissions measured over the
transient on-highway FTP were reduced and fuel consumption and
horsepower remained relatively unaffected. Further optimization of the one
engine would likely minimize the trade-off seen to HC emission as well.
Based on the information discussed above, and elsewhere in this
document, EPA finds that the proposed standards are feasible for the affected
-------
84
DRAFT
engines, considering the cost of implementing the necessary technology within
the available leadtime.
2.6. Lowest Feasible Emission Standard
In setting emission standards for large nonroad CI engines, EPA's goal
is to realize the greatest degree of emission reduction achievable through the
application of technologies which will be available to these engines considering
the cost of such technologies within the period of time available as well as
noise, energy and safety factors.9 Consideration of these criteria has resulted
in EPA's decision to propose a NOx emission standard at 6.9 g/bhp-hr (9.2
g/kw-hr), smoke standards at the current on-highway certification level, and
no standards at this time for HC, CO and PM emissions. EPA's proposal to
set standards at these levels was affected in particular by the following goals:
(1) EPA's intent to implement emission standards that could feasibly be met at
the earliest practicable date, given leadtime constraints; and (2) EPA's concern
that its methods of testing emissions accurately represent in-use emissions
from nonroad engines.
It is EPA's assessment that the significant test procedure and timeline
constraints that must be overcome to meet emission reductions greater than
those proposed are not achievable given the timeline constraints required for
implementation.
2.6.1. Lowest Feasible NOx Emission Standard
Under Section 213(a)(3), the emission standards proposed in this
rulemaking shall achieve the greatest emission reduction available, given the
constraints mentioned above. Moreover, in determining what degree of
reduction is available, EPA shall first consider standards equivalent in
stringency to standards for comparable motor vehicles; taking into account
technological feasibility, costs, safety, noise and energy factors.
9 See CAA, Section 213(a)(3)
-------
DRAFT 85
It will not be feasible in the near future for nonroad engines to attain as
low a NOx emission standard as is currently required for on-highway engines.
This is because nonroad engines operate in a very different environment than
on-highway engines. These differences in operation and function create
unique constraints that a nonroad engine manufacturer must consider even
when designing engines that are very similar to on-highway engines.
Since this proposed rule represents EPA's first regulation of these
nonroad engines, there has previously been no incentive for engine
manufacturers to use emission performance as a design constraint. Thus, these
engines currently produced for the nonroad market do not incorporate the
range of emission control technologies typically used in current on-highway
engines.
Nonroad operational characteristics are substantially different from on-
highway characteristics. Thus, the process of setting standards for engines
installed in nonroad equipment is influenced by some unique constraints that
EPA has not faced when regulating on-highway engines. For example, while
on-highway trucks generally haul merchandise as their only function, nonroad
equipment perform a large number of functions, among them hauling, digging
and loading. These functional differences limit the ability of existing test
procedures to adequately represent nonroad emission reductions for all
pollutants, and limit the flexibility of nonroad equipment to easily
accommodate on-highway emission control systems that cause physical
changes in engine performance and packaging.
EPA has determined that 6.9 g/bhp-hr (9.2 g/kw-hr) represents the
lowest feasible NOx standard achievable in the near future. This
determination was made based on the analysis discussed in the following
sections, which include the following assessments.
• An assessment of the range of technology that EPA expects will be
available to meet a lower NOx standard than proposed,
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86
DRAFT
• An assessment of the ability of nonroad engine and equipment
manufacturers to meet a NOx standard lower than that proposed
given the timeline constraints, and
• An assessment of the ability of existing test procedures to
characterize NOx emissions at levels lower than the proposed
standard.
2.6.1.1. Technology Required for Lower than Proposed NOx Standard-EPA has
determined that a 6.9 g/bhp-hr (9.2 g/kw-hr) NOx standard represents the
limit for most engine families of what can be achieved with fuel injection
system and combustion chamber design changes without causing significant
and irretrievable losses in performance (e.g., fuel economy, power).10 The next
step in emission reduction would require the application of more sophisticated
technologies that can achieve even lower NOx emission levels without
significantly sacrificing performance. EPA analyzed the technologies that
would have to be used to maintain engine performance while meeting a NOx
standard lower than proposed. Turbochargers, air to air aftercoolers, and/or
electronic fuel injection systems were commonly used in on-highway engines
in the 1990 model year to meet a 6.0 g/bhp-hr (8.0 g/kw-hr) NOx standard.
EPA believes that nonroad engine manufacturers would generally be capable
of meeting a 6.0 g/bhp-hr (8.0 g/kw-hr) standard if each of these three
technologies were readily applicable to nonroad engines. This makes 6.0
g/bhp-hr (8.0 g/kw-hr) the next logical tighter NOx emission standard should
a standard below 6.9 g/bhp-hr (9.2 g/kw-hr) be considered.
EPA tabulated in Table 2-19 the range of emission control technology
required to achieve the proposed NOx standard of 6.9 g/bhp-hr (9.2 g/kw-hr)
based on data collected on engines tested by EPA and industry, and the range
required to achieve the next logical lower NOx standard of 6.0 g/bhp-hr (8.0
1 See Chapter 2 4. Beyond a reasonable level, reduction of fuel economy and power are particular problems
for nonroad engines because a percentage of equipment manufacturers could have to redesign fuel tank sizes to meet
customer demands for full day operation between refuelings and/or redesign of powertrain component as necessary
to minimize the impact of engine power and torque changes on equipment
-------
DRAFT 87
g/kw-hr) based on EPA's 1990 model year certification on-highway heavy-
duty engine database. Using these data EPA estimated the change in
technology mix that would occur should EPA require a tighter NOx standard
than that proposed.
Table 2-19 shows a shift from the more conventional technologies
projected to be needed to meet the 6.9 g/bhp-hr (9.2 g/kw-hr) NOx standard
to the more sophisticated systems to meet the next logically lower (i.e., 6.0
g/bhp-hr (8.0 g/kw-hr)) NOx standard. The most significant shifts to meet a
standard below that proposed involve a substantial increase in the use of
turbochargers, air to air aftercoolers, and electronic fuel injection systems.
Table 2-19 shows an increase in turbocharged market share of 28 percentage
points. This represents those engines that would be converted from naturally-
aspirated engines to turbocharged engines. Table 2-19 also shows an increase
of 51 percentage points in engines using air to air aftercooler technology, and
an increase of 13 percentage points in engines using electronic fuel control
technology.
For a number of reasons discussed in the following sections, increased
use of these three technologies would not be feasible for nonroad use within
the proposed timeline.
2.6.1.2. Timeline Constraints of a Lower NOx Standard- A NOx standard
lower than proposed would require increased leadtime to allow engine
manufacturers to make engine design changes needed to incorporate more
advanced emission control systems, and to allow equipment manufacturers to
make equipment design changes necessary to accommodate turbochargers and
air to air aftercoolers. EPA believes that the setting of a lower NOx standard
would thus delay the implementation of standards by at least four years. Such
a delay is not justified given the significant benefits available from
implementing a 6.9 g/bhp-hr (9.2 g/kw-hr) NOx standard.
-------
88
DRAFT
Table 2-19
Estimated Technology Market Percent Change
Due to Tighter NOx Standard
Technology
6.9 g/bhp-hr
6.0 g/bhp-hr
Market Change
market %
market %
market %
Naturally Aspirated
35
7
-28
Turbocharged
65*
93
+28
Air-Water Aftercooler
25
13
-12
Air-Air Aftercooler
5'
56
+51
Elect Fuel Iniect
0
13
+13
This represents the current market share. fcHA expects no increase due to trie proposed rule.
As discussed in Chapter 2.3.2, EPA has determined that the proposed
NOx emission standard can be met with a range of engine emission control
technologies that will have minimal impact on engine and equipment design
and thus can be reasonably developed on the current proposed timeline.
However, EPA has also determined that a more stringent NOx standard would
directly impact a large percentage of engine and equipment manufacturers that
would have to design engines and equipment to accommodate turbocharger
systems, or air to air aftercooler systems.
EPA believes that such a large design effort to accommodate more
advanced technologies would require additional leadtime. First, engine
manufacturers would need more leadtime to implement more stringent
standards because the aggressive timelines proposed in this notice are based
on the timetable used in California's nonroad regulations, which mandate a
NOx emission standard of 6.9 g/bhp-hr (9.2 g/kw-hr) for similar engines.
Under EPA's current proposal, manufacturers would be able to use the same
engine designs to meet both California and EPA standards. Manufacturers
began developing systems to meet California requirements two years ago. To
begin now to develop more advanced systems for EPA would require more
leadtime and a later implementation date. EPA estimates that lower standards
-------
DRAFT 89
than proposed in this notice would require a delay of two to four years for
implementation because manufacturers would lose the two year headstart they
currently have developed for designs to meet a 6.9 g/bhp-hr (9.2 g/kw-hr)
NOx standard, and manufacturers would require an additional two years to
design the more advanced technologies required to meet a lower standard than
6.9 (9.2).
Moreover, to meet lower standards than those proposed, significant
design changes would be required for the nonroad equipment which such
engines would operate. Turbochargers would have to be used on a
percentage of low horsepower engines (i.e., less than 100 hp (74.3 kw)) that
were previously naturally aspirated designs. These are engines that are more
likely to be used in equipment applications with the tightest powertrain and
packaging design constraints. Thus, there is increased risk that a percentage of
equipment applications that would need to convert from naturally aspirated to
turbocharged engines could require substantial redesign to accommodate the
resulting packaging and performance changes.
Air-to-air aftercoolers would have to be used on higher horsepower
engine designs (i.e., greater than 100 hp (74.3 kw)) that are currently at the
efficiency limit of the engine designs' aspiration systems. Use of air-to-air
aftercoolers would require substantial space for the large heater core
assemblies required to make these nonroad systems efficient on any
application. Moreover, there are technical limitations that cause air-to-air
aftercoolers to perform less effectively on nonroad applications than on-
highway applications. Nonroad engine applications generally operate at lower
speeds and in dirtier environments than on-highway applications. As a result,
additional hardware, such as high volume fans and dust scrapers would be
necessary to maintain the high air flow around the aftercooler core that is
needed for effective use of air-to-air aftercooling. Even large equipment
cannot accommodate this level of packaging alteration without substantial
-------
90 DRAFT
redesign. Therefore, equipment impacts are highly likely when either of these
technologies is employed.
Coping with such substantial equipment impacts within the proposed
regulatory implementation schedule would be extremely difficult. An
equipment manufacturer's assessment of the impact cannot begin until the
engine manufacturer has determined which control strategy it will employ and
shares that decision with its customers. It is estimated that making the
necessary design changes to the equipment powertrain or packaging would
require an effort of similar magnitude to that required to design the engine
changes. EPA estimates that two to four years of additional leadtime over the
time needed by engine manufacturers would be required by equipment
manufacturers to redesign their products to meet a lower NOx emission
standard.
Therefore, EPA concludes that a lower NOx emission standard would
require a delay of the initial implementation of standards by at least four
years.
2.6.1.3. Ability of Proposed Test Procedures to Measure Emissions From
Nonroad Engines Built to Meet a Lower NOx Standard- When setting a standard,
EPA must consider not only the ability of manufacturers to meet that standard
in the available leadtime, but must also consider its ability to test compliance
with that standard. As discussed in Chapter 2.1.1 and again below, EPA
believes that the test procedures currently available have only been adequately
shown to measure NOx emission and smoke from nonroad engines at the
proposed levels. EPA is working on an aggressive schedule to develop test
procedures that adequately characterize the in-use emission performance of the
range of technologies that could be used to reduce nonroad engine emissions
beyond the proposed 6.9 g/bhp-hr (9.2 g/kw-hr) standard.
As discussed in Chapter 2.1.1, current data and research indicate the
proposed 8-mode steady state test procedure is capable of measuring NOx
reductions when the standard is set at 6.9 g/bhp-hr (9.2 g/kw-hr) or above.
-------
DRAFT 91
However, information is not available to support the suitability of these test
procedures for more stringent NOx standards. The proposed test procedures
may not be capable of measuring NOx emission from the most advanced
electronic fuel injection technology which some manufacturers could be forced
to use should the NOx standard be lower than proposed. Moreover, a lower
NOx emission standard could significantly increase HC and PM emissions, but
the proposed 8-mode test procedures have not yet been demonstrated to
accurately measure these emittants.
2.6.1.3.1 The Proposed Test Procedures Lack of Demonstrated Ability to Properly
Characterize NOx Emissions from Electronic Fuel Injected Engines- EPA has
determined that it is feasible for the proposed 8-mode steady-state test
procedure to accurately measure NOx emission reductions on engines using
conventional analog (mechanical) fuel control systems. As discussed in
Chapter 2.1.1, these systems have been shown through data collected by
industry and EPA to generate comparable NOx emission levels on both the
more transient on-highway FTP and the steady-state 8-mode test procedure.
These data suggest that a lower percentage of the composite NOx emission
was generated during transient portions of the test cycle as compared to
steady-state portions, and therefore NOx emission generated by engines using
analog fuel system designs is less sensitive to test procedure variances that
involve transient operation. Since engines using analog fuel system designs
are insensitive to transient operation with respect to NOx emission, EPA can
propose use of the 8-mode steady-state test without concern. This is consistent
with the science of NOx control since analog systems have no ability to make
instantaneous step changes in critical operating parameters such as fuel
delivery and timing.
On the other hand, the more sophisticated electronic fuel control
systems are digital in nature. Such systems can be customized to actually
generate higher levels of NOx during transient operation, thus compromising
EPA's ability to predict that emission test results generated on the 8-mode
-------
92 DRAFT
steady state test procedure are representative of any possible in-use operation.
For example, should a manufacturer decide to use its electronic control system
to reduce engine smoke by advancing fuel injection timing during heavy
accelerations, smoke would decrease, but NOx emission would increase. Such
a strategy would increase NOx in-use in a manner that could not be
accounted for in an 8-mode steady state emission test.
Electronic fuel control systems would not be necessary to meet the
proposed NOx emission standard. In addition, engine manufacturers have
indicated they would not use electronic fuel control to meet the proposed
standards, due to development timelines and significantly higher cost. As
shown in Table 2-19, should EPA require the next lower feasible NOx standard
of 6.0 g/bhp-hr (8.0 g/kw-hr), engines with electronically controlled fuel
control systems would be needed on 13% of the market. EPA could not be
sure that the in-use performance of these engines would be properly
characterized by the proposed steady-state test procedures. By proposing a
6.9 g/bhp-hr (9.2 g/kw-hr) NOx standard today, EPA is forcing only those
technologies the emission effects of which are within the range that the
proposed test procedure is able to measure. As discussed in the next section,
EPA is aggressively working with industry to determine appropriate test
procedures to ensure that the emissions impact of all technologies that become
available in the future, including electronic fuel control systems, will be
properly characterized.
2.6.1.3.2 The Proposed Test Procedures Lack of Demonstrated Ability to Measure
HC and PM Emissions- Some technologies that reduce NOx emissions also have
a tendency to increase HC and PM emissions. This phenomenon is known as
"emission tradeoff" and is based on the chemistry by which these pollutants
are formed (pollution formation is discussed in Appendix B). Technical
literature published by EPA and industry (12,13,14,15) demonstrate that the
rate of HC and PM emissions trade-off tends to increase exponentially as the
NOx emission standard gets lower. For example, Figure 2-02, taken from one
-------
DRAFT
93
of these publications(12), shows the NOx and PM emission relationship. The
"current technology average" line represents on-highway heavy-duty engines
produced between the 1988 and 1990 model years. Observing this line, as a
manufacturer reduces NOx emission levels from current nonroad baseline
levels (11 g/bhp-hr (14.7 g/kw-hr)) down to levels necessary to comply with
the proposed NOx emission standard, or a reduction of about 4 g/bhp-hr, the
amount of PM emission tradeoff is small. To reduce NOx emission levels even
further below the 6.9 g/bhp-hr (9.2 g/kw-hr) proposed standard, the rate of
PM tradeoff begins to increase rapidly as characterized by the increasing slope
of the NOx versus PM curve.
c
X
CL
z
CD
uj
H
3
O
o
£
ce
<
Q.
(A
O
1.3
—
1.2
—
1.1
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.9
—
.8
.7
.6
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.5
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METHANOL
6V-92 TAB
13-MOOE
I L
CURRENT TECHNOLOGY AVE RAGE
AOVANCED TECHNOLOGY ESTIMATE
8
10
Figure 2-02
Particulate to NOx Trade-Off
Transient Emission Data
-------
94 DRAFT
Figure 2-02 suggests that, should EPA propose a NOx standard lower
than proposed, it would also be necessary to, at the very least, set upper
emission limits for HC and PM emissions to preclude significant increases in
these emittants. However, since data collected using the proposed 8-mode
steady-state test procedure are inconclusive as to whether increases to HC and
PM emissions can be accurately measured (see Chapter 2.1.1), EPA currently
would have no way to enforce HC and PM emission limits. It would be
inappropriate to promulgate a lower NOx standard when no means are
currently available to measure accurately and verify that no significant
increases in HC and PM emissions result from a lower NOx standard. EPA is
proposing the NOx standard at 6.9 g/bhp-hr (9.2 g/kw-hr) because it not only
provides a substantial NOx emission reduction, but also minimizes the risk of
causing a large HC and PM emission tradeoff.
2.6.1.3.3 Time for Test Procedure Evaluation and Validation- EPA is currently
involved in an aggressive program, in partnership with the Engine
Manufacturers Association (EMA), to determine what a realistic test procedure
should be in order to predict even greater emission reductions than those
proposed in this rule. This test procedure would be capable of predicting
emissions of NOx from the full range of advanced technologies, such as
electronic fuel control, that are expected to result should tighter standards be
promulgated at a later date. This test procedure would also be capable of
predicting HC, CO and PM emissions. It will take time to develop such a
procedure for reasons explained as follows. The operating characteristics of a
representative range of equipment must first be evaluated. Existing emission
test procedure options must then be evaluated against prototype test
procedures based on real in-use operation data. Should it be determined that
new test procedures must be developed, additional time would be required to
develop the new test procedures, and to collect sufficient data with the new
test procedures to determine effective emission standards.
-------
DRAFT 95
Given the aggressive timeline for implementation of NOx standards,
EPA does not believe that it can complete its development of new test
procedures and propose and finalize such procedures in time to implement
these procedures in testing the engines subject to these regulations. Moreover,
manufacturers will not be able to design their engines to comply with new test
procedures until those procedures are promulgated.
2.6.1.4 Conclusion-EPA estimates that proposing a lower NOx emission
standard would delay implementation of nonroad standards by at least four
years. The proposed rule would realize substantial NOx emission reduction in
the near future because the proposed NOx standard is within the measurement
capability of the proposed test procedures. The proposal thus results in
significant NOx emission reductions in the near term while work is going on
to develop test procedures for more stringent standards and while
manufacturers work to design engines and equipment capable of meeting a
lower standard at a later date.
-------
96 DRAFT
-------
DRAFT
Chapter 2 References
1. Bozek, John, Use of Compressed Natural Gas or Methanol In Lieu of
Diesel Fuels in Nonroad Applications, Internal EPA memo, September 26, 1991
2. McConnel, G., Proceedings of Institute of Mechanical Engineers 178,1,38,
1963-1964 p.1001-1014
3. Ullman, Terry L., et al, Effects of Fuel Aromatics, Cetane Number, and
Cetane Improver on Emissions from a 1991 Prototype Heavy-Duty Diesel Engine,
SWRI SAE paper #902171 October 22,1990
4. MVMA National Diesel Fuel Survey Winter 1991
5. Needham, J.R., et al, The Low NOx Truck Engine, SAE paper # 910731
March 1, 1991
6. Stump, Gerhard, et al, Fuel injection equipment for Heavy Duty
Engines for the U.S. 1991/1994 Emission Limits,mpp, SAE paper # 890851.
7. Hil, R.W., et al, The optimized Direct Injection Diesel Engine for Future
Passenger Cars, SAE paper # 880419, February 29, 1988
8. Ikegami, Makoto, et al, Combustion Chamber Shape and Pressurized
Injection in High-Speed Direct-Injection Diesel Engines, SAE paper # 900440 Feb
1990
9. Shindoh, Shigeru, et al, The Effect of Injection Parameters and Swirl on
Diesel Combustion with High Pressure Fuel Injection, SAE paper # 910489 Feb
1991
97
-------
98
DRAFT
10. McCarthy, John H., Study of the Significance of NOx Deterioration
Factors in Proposed Regulation of Nonroad Diesel Cycle Engines Greater Than or
Equal to 50 Horsepower, EPA memorandum dated December 20, 1991.
11. Brezonik, Mike, Cummins' New Off-Highway Electronic Control System,
by Mike Brezomck, Diesel Progress Engines and Drives, July, 1992.
12. Toepel, R., et al, Development of Detroit Diesel Allison 6V-92TA
Methanol Fueled Coach Engine, SAE#831744, October, 1983
13. Stumpp, G., et al, Fuel Injection Equipment for Heavy-Duty Diesel
Engines for U.S. 1991/1994 Emission Limits, SAE#890851
14. Gill, A., Design Choices for 1990's Low Emission Diesel Engines, SAE#
880350, February, 1988
15. U.S. Environmental Protection Agency, Office of Mobile Sources,
Regulatory Impact Analysis, Oxides of Nitrogen Pollutant Specific Study and
Summary and Analysis of Comments: Control of Air Pollution from New Motor
Vehicles Engines: Gaseous Emission Regulations for 1987 and Later Model Year
Light-Duty Vehicles, and for 1988 and Liter Model Year Light-Duty Trucks and
Heavy-Duty Engines; Particulate Emission Regulations for 1988 and Later Model
Year Heavy-Duty Diesel Engines, March 1985.
-------
DRAFT
Chapter 3: Cost
This chapter estimates the costs of complying with the NOx emission
and smoke opacity standards for the applicable 1996 and later model year
compression-ignition engines at or above 50 horsepower (37.5 kilowatts). Four
main types of cost are analyzed: 1) variable hardware costs, 2) production
lifecycle fixed costs including engineering development costs, mechanical
integrity testing costs, and test facility costs; 3) annual fixed costs including
engine certification costs, in-use enforcement costs, emission defect reporting
costs, and selective enforcement auditing costs; and 4) consumer costs
including the increase in the retail price and engine operating costs.
Several underlying assumptions are used in this analysis due to the
difficulty in obtaining data and to the proprietary nature of some data which
was obtained. EPA assumes that
• all engines comply in model year 1996 (i.e., no staggering of
horsepower groups).
• ten manufacturers participate in the averaging program.
• the number of years which a manufacturer produces an engine
family is ten years on average11 (i.e., the production life).
Consequently, EPA assumes that a new engine design will be
introduced after ten years.
11 The 10 year estimate is the typical production cycle over the last 20 years as described by manufnctun r» ¦ •
conversations with EPA.
99
-------
100 DRAFT
• manufacturers will amortize and discount all costs which are
recoverable from future year production (e.g., mechanical integrity
testing cost).
• the hourly rate for labor is $60 including overhead.
• the sales distribution is equivalent to the engine family distribution
for purposes of calculating research and development costs.
• the annual rate of growth of sales for these engines is 2 %.
• the number of engine families does not grow over time.
• no future regulations setting more stringent emission standards are
considered.
• the increase in retail price to the consumer is equivalent to the on-
highway mark-up percentage over manufacturer cost.
All costs are summarized at the end of the chapter in section 3.6.
3.1. Variable Hardware Cost
Variable hardware costs are those costs for hardware changes made to
engines in order to comply with new emission standards. Hardware costs are
variable since they depend on production volumes.
3.1.1. Estimation of Weighted Average Variable Hardware Cost Per Engine
EPA has developed a fleetwide weighted average variable hardware
cost per engine estimate. The weighting is based on the percentage of the fleet
which is estimated to require the use of each technology in order to meet the
emission standard.12 EPA's estimates of the technology required to meet the
proposed NOx emission and smoke standards are multiplied by the estimated
engine manufacturer's cost for each technology. This variable hardware cost
per technology was determined from proprietary manufacturer submissions.
These submissions formed a range of cost which varied by the size of the
engine employing the technology to reduce NOx and smoke emissions. For
instance, the cost of a turbocharger is low because it is estimated that the
engines which would convert to a turbocharger for emissions purposes would
12
Refer to Section 2 2 6 , for the discussion of the technology required for the fleet to meet the NOx emission
standard
-------
DRAFT 101
be the small, naturally-aspirated engines. Therefore, the weighted average
variable hardware cost was calculated using the formula
t v,'
calculate what EPA considers the worst case cost estimate under an averaging program, EPA has assumed onlv ten
manufacturers participate in averaging and that 5% of the engines still incorporate turbochargers Even in t)u~
instance, the cost analysis shows the rule to very cost-effective
-------
102 DRAFT
EPA considered developing an analysis of all engines available for sale
in the United States in order to estimate the increase in manufacturer cost due
to emission control strategies. Complete sales information would be necessary.
Further, manufacturer's would need to disclose engine development plans to
EPA. However, this industry is very sensitive to the disclosure of this
information. The industry would not authorize release of proprietary
information in the Regulatory Support Document and, in many cases, would
not provide proprietary information to EPA for analysis. Therefore, EPA
decided to use the weighted average variable cost methodology, as a
reasonable alternative methodology.
3.1.2. United States Consumption
The total annual United States' apparent consumption (production -
exports + imports) of diesel engines14 is based on the national sales information
available to EPA from the U.S. Department of Commerce, Bureau of the
Census (DOC/BOC). For instance, in 1989 DOC/BOC estimates that 217,456
nonautomotive diesel engines were produced in the United States. This
number includes the following end applications.
1. Oil field and petroleum related generating and stationary equipment.
2. Other generating sets
3. Irrigation
5. Off-highway mobile construction equipment
6. Marine, except outboard
7. Railroad, motive power type
8. Agriculture vehicular
9. Other general industrial
The Bureau estimates that 42,331 were exported and 240,712 were imported.
This implies that the 1989 apparent consumption of diesel engines in the
United States was 415,837.
14 The estimate of U S consumption is provided in Table A-08 in Appendix A
-------
DRAFT 103
The proposed rule excludes engines used in locomotives, marine
propulsion and auxiliary power generation, stationary sources, and nonroad
engines under 50 horsepower. EPA estimates these exclusions decrease the
apparent consumption by about 30%, based on consideration of nonroad diesel
engine population data by equipment category which were obtained for the
Nonroad Engine and Vehicle Emission Study in consideration of the
Department of Commerce apparent consumption estimate. Based on this 30 %
reduction, EPA estimates the 1989 United States apparent consumption of all
compression-ignition engines greater than or equal to 50 hp to be
approximately 290,000 units.
EPA feels that it is reasonable to assume an average annual rate of
growth in sales of these engines. An annual growth rate of 2% is assumed.
This growth rate is estimated based on the long term growth rate of the
economy, the farm machinery and equipment industry, the construction
equipment industry, and the internal combustion engine industry.
Gross national product (GNP) for the United States is estimated by the
Department of Labor (DOLXl) to have a long term average annual rate of
change between 1.5 and 2.9 percent (2.3 percent in the moderate growth of the
economy scenario) over the period 1990 to 2005. This average annual rate of
change is based on the value of GNP in billions of 1982 dollars. The projected
rates of change for the moderate and low growth scenarios are lower than
historical average annual rate of change over the 1975 to 1990 period which
was 2.9 percent.
According to the U.S. Industrial Outlook for 1992, the outlook for the
farm machinery and equipment industry is not easy to predict, depending in
large part on the global economy, global weather, and foreign and domestic
agricultural policies. While the number of farms has declined over the last
four decades, farms have become larger and agriculture has become more
mechanized further complicating growth estimates. According to the DOL, in
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104 DRAFT
the agricultural industry, employment is expected to decrease between 0.2 to
0.7 percent and output (in dollars) to increase between 1.4 and 2.4 percent.
Projected average annual growth in output for the farm and garden machinery
industry between 1990 and 2005 is 1.0 percent while the rate for employment
is 0.4 percent, both in a moderate growth scenario. These numbers generally
support the conclusion in the U.S. Industrial Outlook and seem to indicate that
output growth for the farm equipment and machinery industry will increase
but be less than the rate for GNP. The DOL based their projections on the
assumption that demand will increase in the farm and garden machinery
industry as a result of capital spending by the real estate and farming sectors.
According to the U.S. Industrial Outlook, the construction machinery
industry is expected to see a 2.2 percent increase in sales for the period of 1992
to 1996. Increased expenditures in infrastructure, as well as construction of
new power generating plants, resource recovery plants, and water treatment
facilities are given as potential reasons for the increase in sales in this industry.
The report also notes that construction machines will be more efficient,
meaning that fewer machines will be required. Such changes could serve to
reduce the amount by which the industry is expected to expand. According to
the DOL employment in the construction industry is expected to increase
between 0.5 and 1.6 percent which is less than the 1975-1990 historical average
annual rate of change of 2.5 percent. Similarly, output for the construction
industry is expected to increase between 1.0 and 2.6 percent which is less than
the 1975-1990 average annual rate of change of 2.8 percent. In a moderate case
scenario, the construction equipment industry is projected to have an average
annual growth rate of output of 2.2 percent and of employment of -1.5 percent.
The DOL based these projections on the assumption that there will be
increased purchases of construction machinery due to investment. DOL
assumed that demand should be strong because of maintenance of the nation's
infrastructure. This data seems to indicate that the average annual rate of
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DRAFT 105
growth for the construction machinery industry correlates well with the
projected rates of GNP.
The DOL estimates the projected average annual growth rate of output
in the engines and turbines manufacturing industry to be 0.9 percent over the
1990-2005 period. Over this period, DOL projects that employment in this
industry will change by a -1.4 percent average annual rate of change. DOL
based this projection on the assumption that imports are expected to increase
their market share slightly while exports will recover due to expanding
markets abroad.
Based on this information, EPA is assuming that sales will have an
average annual growth rate of 2% over the 1996 to 2026 time period. This is
itself based on two assumptions. First, that the average annual growth rate of
sales is equivalent to the average annual growth rate of output. Second, that
the average annual growth rate of output for the engines covered by this
regulation is similar to the rates given above. The assumed average annual
growth rate of sales of 2% for engines covered by this regulation is
qualitatively estimated and should not be viewed as a precise measurement of
future sales activity. It should be noted that the data presented above applies
to larger categories of activity than the industries which produce the specific
engines covered by this proposal. Because an extensive quantitative analysis
would be required to produce a more precise projected average annual growth
rate range, EPA decided to use an qualitatively derived assumed average
annual growth rate. EPA's rationale for the assumed rate applicable to the
engines covered by this proposal was to choose a rate below the projected
rates for construction machinery industry and above the projected rates for
farm machinery industry.
3.1.3. Annual Variable Hardware Cost
The total annual variable hardware cost is calculated according to the
following formula.
Cra(=$51 *SALESl
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106
DRAFT
In this equation,
C
VHi
- total variable hardware cost
- sales in year i
SALES,
The annual total variable hardware cost is presented in Table 3.7 in section
"3.6. Cost Summary."
3.2. Production Cycle Fixed Costs
The production cycle is the time period starting the first year a new
engine model is sold and ending in the last year of sale. For engines required
to comply with this proposal, the production cycle for engines appears to be 10
years. During this typical production cycle, two minor calibration changes to
an engine model appear to be typical.
Some costs recoverable in the production cycle are incurred one to three
years before production begins. Recalibration, design, mechanical integrity
testing, and some initial certification costs are such costs which are recoverable
across the production cycle. These costs are estimated in this section, with the
exception of some initial certification costs which are described in section
"3.4.1. Initial Certification Costs."
3.2.1. Engineering Development Costs
These costs include costs for engine recalibration, engine redesign and
accumulation of hours on all engine families to ensure their mechanical
integrity. EPA estimates the number of engine families to be 213. See
Appendix D for a detailed discussion of the criteria for categorizing engine
families and the quantitative estimation per manufacturer.
3.2.1.1. Engine Recalibration—Engine recalibration costs reflect the costs
associated with recalibrating the injection timing system to achieve optimized
emissions and performance under the constraints of the NOx emission
standard, maintaining constant performance, and current levels of
reliability/durability. EPA assumes that the injection timing system will be
retarded on 98% of these engine families (209 engine families). This analysis
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DRAFT 107
assumes that, for engine families which require recalibration, the manufacturer
would recalibrate two emission data engines four separate times to meet the
1996 model year NOx emission standard. EPA expects that the manufacturer
will set a calibration for the entire engine family such that the worst case
configuration from an emissions perspective will meet emission standards. It
is assumed that each recalibration would require 20 person-days, 15 for the
technician and 5 for the engineer. The cost estimate assumes an eight hour
day and a cost of $60/hour including labor and overhead. The cost was
calculated according to the following formula.
CR=(PDt+PDe) *8hr/day *$60/hour *2Q9engine families
*2EDE * Arecalibrationsl EDE
where
CR - total recalibration cost
PDt - number of technician person-days required
PDe - number of engineer person-days required
EDE - emission data engine
EPA assumed that these recalibration costs would recur every
production cycle. Therefore, EPA accounted for these costs three times over
the 30 years it takes the fleet to turn over. These costs are amortized and
discounted at 10 percent over each 10 year production cycle of each engine
family.
3.2.1.2. Development Costs-This cost is for development work for
modifying engine families to meet the proposed standards. The development
costs are limited to actual development work by the engine manufacturer. The
design cost for the components (e.g., the turbocharger) is considered in the
variable cost estimate for each component because it is expected that any
supplier's development costs are passed on to the engine manufacturer
through the price of the component.
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DRAFT
EPA estimates that the following system would need to be developed
for a percentage of engine families without such systems in order to meet the
proposed standards. The system categories are:
1. combustion chamber design
It is assumed that engines requiring higher pressure
rotary pumps, turbochargers, and air-to-water
charge air coolers will require some further
development of the combustion chamber. This
involves adjustments to the injectors, redesign of the
combustion bowl, adjustment of the bore or stroke,
or similar modifications to the combustion chamber.
2. turbocharger system
Applying a turbocharger to the engine family
involves determining the proper induction and
exhaust system piping, bracketing, placement of the
turbocharger, determination of proper boost
pressure, etc..
3. aftercooler/intercooler system
Applying an aftercooler/intercooler system involves
the determination of the proper air supply, the
proper placement of the system, the proper
connecting hardware, etc.
4. smoke limitation system
Applying a smoke limitation system involves mostly
calibration work.
The following table presents the estimate of the number of days of
personnel effort required to address the system redesign on average.
Table 3-02
Development Person-Days
system categories:
1
2
3
4
# redesigns
2
2
2
2
Person-Days
per Redesign
machinist's days
9
3
0
0
mechanic's days
5
2
9
8
Technician's days
58
63
87
49
engineer's days
58
63
35
8
Total Person-Days:
260
262
262
130
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DRAFT
109
The total person-days required for each system category is therefore
calculated according to the following equation.
TPD=R*(MA+ME+T+E)
where
TPD
total person-days
R
number of redesigns
MA
machinist's days
ME
mechanic's days
T
technician's days
E
engineer's days
It is assumed that the manufacturers would design two redesigns for each
engine family and pick one which best met their objectives.
The total development cost for these engines is based on the
development person-days per system redesign, the percentages of engine
families incorporating each technology15, an assumed eight hour person-day,
and an hourly rate of $60 including labor and overhead. The total
unamortized and undiscounted development cost estimate is presented in
Table 3-03 below. In order to arrive at an annual cost estimate, the total cost
was amortized and discounted at 10 percent over the assumed 10 year
production life of the engine families. EPA does not account for further design
costs for future production cycles for two reasons. First, uncertainty over what
future design changes would occur makes it impossible to estimate effort
required to maintain emission levels. Second, if manufacturers decide to
redesign certified engine families that are already capable of meeting the
standards it would be for purposes other than complying with emission
standards, such as cost savings or performance enhancement. Therefore, it
15 Refer to Section 2 2 6
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110 DRAFT
would be inappropriate to account for design costs incurred to achieve benefits
other than meeting the basic emission standard requirements.
Table 3-03
Development Costs
design
Full-Time
Person-Days
% engine
families
$/hr
Approximate Total
($million)
combustion chamber
260
35
60
$78
aftercooler
260
10
60
22
turbocharger
262
5
60
1.1
smoke limitation
130
40
60
4.4
TOTAL
$15.5
3.2.2. Mechanical Integrity Testing Costs
Mechanical integrity testing costs represent useful life accumulation and
effort to prove the mechanical integrity of redesigned engine families. It is
assumed that manufacturers will do this testing only on engine families which
change from naturally-aspirated to turbocharged, those which become
aftercooled, and those which receive improved rotary pumps (i.e., 35 % of the
engine families). EPA assumes that manufacturers would not test engines for
mechanical integrity which have not received these design changes because
mechanical integrity should already be proven. It is assumed that
manufacturers would perform one test sequence for mechanical integrity
assurance. The length of the test is assumed to be 1000 hours. The number of
engine families to be tested for mechanical integrity is estimated to be 75 (35%
of 213 engine families). The cost estimate assumes a cost of $60/hour for labor
and overhead and is calculated according to the following formula.
= $60/hour * 1000 hours * 75 engine families
where
Cmrt - total mechanical integrity testing cost
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DRAFT 111
The annual cost would be approximately $1,700,000, which represents
the total cost amortized over the expected 10 year production life of the engine
family discounted at 10%.
3.3. Test Facility Cost
These are the costs for construction and/or expansion of certification
quality test facilities. Most manufacturers already have test facilities capable of
conducting the proposed test procedures. EPA estimates that each
manufacturer will build one additional steady-state certification quality basic
test cell. Only 1 per manufacturer would be needed because most
manufacturers already have built test facilities to meet their development
testing needs. The additional one cell accounts for test capacity needed for
certification. Therefore, industry-wide there will be 28 additional test facilities
built.
For the proposed test procedure, EPA estimates that the basic test cell
consists of a water brake or eddy current dynamometer, basic instrumentation
and analyzers, and automated data processing and wiring. The test cell would
not include a motoring dynamometer, would not include the building facility
(e.g., the walls of a test cell), and would only have the capability to do raw gas
sampling. The estimated cost of each basic cell is $200,000. This $200,000
consists of approximately $75,000 for a water brake or eddy current
dynamometer, $100,000 for basic instrumentation and analyzers, and $25,000
for automated data processing and wiring. EPA estimates that the water brake
or eddy current dynamometer can be amortized over 30 years, the basic
instrumentation and analyzers can be amortized over 10 years, and the
automated data processing and wiring can be amortized over 5 years. These
costs are amortized and discounted at 10 percent.
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112 DRAFT
These amortization periods are based on the useful life of the
equipment. Therefore, EPA is assuming that the water brake or eddy current
dynamometer is useful for 30 years, that the basic instrumentation and
analyzers are useful for ten years, and the automated data processing and
wiring is useful for 5 years. Replacement is assumed after these time periods.
Therefore, for the thirty year period covered by this cost analysis, the basic
instrumentation and analyzers would be replaced twice and the automated
data processing and wiring would be replaced five times. As shown in table
3.7, the annual cost is approximately $900,000, which represents the total test
cell cost amortized and discounted at 10%.
3.4. Annual Administrative Cost
Annual fixed costs described in this section are certification and
enforcement costs which the manufacturers are estimated to incur due to the
regulatory program which is being promulgated. Variable hardware costs are
also considered to be annual costs but have been previously presented16.
3.4.1. Certification
The proposed certification program mandates testing, recordkeeping,
and reporting costs a manufacturer incurs in year one. These costs are
incurred because the engine manufacturer must prove to EPA that its engines
are designed and will be built such that they are capable of complying with
the emission standards over their full useful life. Manufacturers are required
to submit descriptions of their planned product line, including detailed
descriptions of the emission control system, and test data. This information is
organized by "engine family" groups expected to have similar emission
characteristics. All manufacturers must describe their product and supply test
data to verify compliance. EPA will conduct a limited number of
"confirmatory tests" to audit manufacturer results. Confirmatory tests require
16 See Section 3 1 Variable Hardware Cost
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DRAFT 113
shipment to EPA's laboratory. Manufacturers must also retain records. These
tasks are repeated for each model year, typically previous data and
information can be "carried over" when no significant changes have occurred.
EPA's estimate of the total certification program costs to the manufacturers is
explained in EPA's Statement for Information Collection Request and the result
is presented in Table 3.7 and is approximately $9,000,000 per year.(5)
3.4.3. Averaging, Banking, and Trading
EPA is proposing an averaging, banking, and trading (ABT) program for
the engines covered by this proposal. The program requires the periodic
reporting and recordkeeping by manufacturers electing to participate in the
ABT program.(6) Manufacturers would submit information regarding the
calculation of projected and actual generation and usage of emission credits in
an initial report, end-of-year report, and final report. These reports will be
used for certification and enforcement purposes. Initial reports are included in
the certification applications that are submitted prior to the sale of any engines
of an engine family in the United States. End-of-year and final reports are to
be submitted after the end of the model year in a summary form.
Manufacturers would also maintain records for eight years on the engines and
engine families included in the program.
EPA estimates that 28 engine manufacturers will be affected by this
rulemaking. Assuming a 33% participation rate in the ABT program based on
EPA experience with the on-highway ABT program, 10 manufacturers are
likely to be involved in this information request. EPA estimates that this
information collection will cost the respondents approximately $300,000 per
year.
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DRAFT
3.4.4. In-Use Enforcement Costs
EPA's proposed enforcement program will be based on testing "properly
maintained and used" in-use engines. This testing program for nonroad
engines will be the same program EPA currently uses for in-use testing of
motor vehicles and engines under section 207(c) of the Act. Because nonroad
engines will be subject to in-use testing by EPA, manufacturers may choose to
begin monitoring the performance of their in-use engines. However, with the
information currently available, EPA is unable to estimate the amount
manufacturers would spend on in-use testing. EPA believes that in-use testing
by the manufacturers will be a relatively small cost of the proposed rule
because NOx emission deterioration on compression-ignition engines is
typically very low.(7)
3.4.5. Emission Defect Reporting Costs
EPA's proposed enforcement program includes emission defect
warranty reporting requirements. EPA estimates that manufacturers would
have a burden of 262 hours per year per manufacturer for emission defect
reporting requirements for this proposal.(8) As shown in Table 3.7, EPA
estimates that this information collection will cost the respondents
approximately $13,000 per year.
3.4.6. Selective Enforcement Auditing Costs
EPA is also proposing a new nonroad engine assembly line audit
program, a Selective Enforcement Auditing (SEA) program.(9) This program
will be similar to the on-highway heavy-duty engine SEA program. For
nonroad engines, EPA believes this program is especially important due to the
nature of the nonroad industry. Since most nonroad equipment (and engines)
are not registered like on-highway vehicles, in-use enforcement could be
difficult and costly for EPA and industry. Additionally, manufacturers' recall
response rates to have repairs performed may be low since contacting engine
owners through registration records will not be possible. Therefore, detecting
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DRAFT 115
noncompliance at the assembly line, through SEAs, will be the most cost-
effective enforcement means for EPA and industry.
EPA estimates that more than half of the nonroad engine manufacturers
will voluntarily collect assembly line emission test data. EPA requests that
manufacturers submit this data to EPA, but EPA does not set requirements for
manufacturers to follow during voluntary testing.
Manufacturers are required to provide EPA with projected annual sales
data. This data is used by EPA to help determine which manufacturers will
receive SEAs. EPA estimates that ten SEAs will be conducted per year with an
average of eight tests per audit. These estimates are consistent with the on-
highway heavy-duty engine SEA program. For every SEA the manufacturer
has reporting, recordkeeping, and testing requirements. Table 3.7 presents the
total annual SEA cost estimate.
3.4.7. Importation of Nonconforming Nonroad Engines
EPA is proposing certain restrictions on the importation of
nonconforming nonroad engines. Such restrictions are based on the existing
regulations for the importation of nonconforming motor vehicles and motor
vehicle engines. The proposal permits independent commercial importers
(ICIs) who hold valid certificates of conformity issued by EPA to import
nonconforming nonroad engines. Under this program, the ICI must certify the
engine to applicable U.S. regulations via the certification process before an
engine is imported. The forms used for importation will be identical to those
used for motor vehicles and engines currently imported into the United States.
Discussions with specialists on the industry to be regulated by this
proposal suggest that there is at present no significant importation of nonroad
engines by non-manufacturers. However, EPA has provided a cost estimate
based on a total of 50 engines imported by ICIs to reflect the possibility that
some such importation may occur. Table 3.7 provides the annual cost estimate
for importation.
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116 DRAFT
3.4.8. Exemptions
Under the proposed rule, manufacturers and Independent Commercial
Importer (ICIs) of these engines must report and keep records of nonroad
engines on exempt status. ICIs will submit reports when they want to import
a nonconforming pre-certification nonroad engine or a manufacturer or
business submit a report when they want to conduct a test program which
uses nonconforming nonroad engines. EPA will use this information to verify
the need for the exemption, to verify the validity of the program, and to insure
that the terms and conditions of the regulations are met. Table 3.7 shows the
estimate of the total annual cost to industry which is approximately $13,000.
3.4.9. Exclusions
Under the proposed rule, a manufacturer may make an exclusion
determination by itself; however, nonroad engine manufacturers or importers
may routinely request EPA to make such determination to ensure that their
determination does not differ from EPA's. The information EPA needs to
make an exemption determination are information such as engine type,
horsepower rating, intended usage, method of usage, other descriptive
information on the vehicle powered, etc. Table 3.7 shows the estimate of the
total annual cost to industry which is approximately $3000.
3.5. Consumer Cost
3.5.1. Increase in Retail Price
The increase in retail price, commonly referred to as a retail price
equivalent (RPE), is estimated according to the method developed for EPA by
Jack Faucett Associates for on-highway engines(lO). Full cost pass through is
assumed. According to this method, the weighted average variable hardware
per engine cost is multiplied by a manufacturer factor that accounts for
manufacturer overhead and profit. Recalibration, design, mechanical integrity,
certification, emission defect reporting, and Selective Enforcement Auditing
costs are added to the result and multiplied by the dealer factor. The
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DRAFT 117
manufacturer factor used here is 1.282 and the dealer factor used here is 1.062.
The RPE increase due to the proposed rule are shown in Table 3.9 and
discussed in section "3.6. Cost Summary."
3.5.2. Engine Operating Cost
In addition to the increased cost of the engine and equipment, EPA
evaluated any change in the cost of operation due to changes in fuel or
maintenance requirements. EPA found little to no change.
3.5.2.1. Fuel Cost-It is expected that all nonroad engine manufacturers
will retard the fuel injection timing on large CI engines in order to reduce NOx
emissions. EPA testing suggests that retarding fuel injection timing to meet
the 6.9 g/bhp-hr NOx standard will increase fuel consumption in the range of
3 to 5 percent.17 The market demands that the equipment manufacturer design
its fuel storage systems to allow a full day of work between refueling.
Therefore, equipment manufacturers design fuel tanks to exceed the daily
work hours by approximately 10 percent (e.g., 11-12 hours on a 10 hour shift).
While fuel economy itself is not as important as power and durability, the
ability to work a full shift without refueling is apparently critical to sales.
The magnitude of the fuel consumption penalty due to the proposed
emission standards will dictate how the engine manufacturer proceeds. If the
fuel consumption penalty is minimal, the manufacturer may avoid adding
additional technology by optimizing existing designs to restore fuel economy
However, if the fuel consumption penalty is between 3 to 5 percent, the engine
manufacturer will often have to add the technology necessary to maintain the
baseline fuel consumption rate. Should an engine manufacturer forego adding
the necessary engine technology, the cost would be passed on to those
equipment manufacturer customers with applications that cannot absorb these
levels of fuel consumption increase without redesigning their fuel tank
systems.
17 Refer to Section 2 41
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118 DRAFT
For this cost analysis, EPA assumed, when system optimization would
not suffice, the engine manufacturer would add those technologies necessary
to restore pre-regulation fuel consumption. Therefore, any costs normally
attributed to higher fuel costs are reflected in higher variable hardware costs
(e.g., for additional aftercoolers and higher pressure rotary pumps) in Section
3.1. This is a reasonable costing approach since, as discussed in Section 2.4.1.,
EPA experience with similar on-highway large CI engines has demonstrated
that the industry-wide fuel consumption will not increase as regulations
become increasingly stringent.
3.5.2.2. Maintenance Cost-The only technology which EPA felt could
likely increase maintenance cost was the addition of a turbocharger to a
naturally-aspirated engine. However, EPA has determined that addition of
turbocharger technology is not necessary to meet standards proposed in this
notice.
To cover those rare cases when a manufacturer might have to
incorporate a turbocharger (e.g.,1998 model year), EPA reviewed maintenance
manuals for on-highway large CI engines which were certified in turbocharged
and naturally aspirated versions. The recommended maintenance schedules
for oil changes appeared no different in the two versions.(ll) EPA could not
identify an increase in any other turbocharger recommended maintenance over
a similar naturally-aspirated engine. Therefore, EPA is not including any
maintenance cost impact.
3.6. Cost Summary
This section summarizes the total industry cost accounted for over the
30 years in which the fleet turns over. EPA has analyzed the costs in the years
in which they occur and the costs in the years in which they are recovered by
retail price increases. Further, EPA has evaluated the stream of costs over
time. Finally, a summary of how costs have been minimized is presented.
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DRAFT 119
3.6.1. Accounting for Costs as They Occur
Manufacturers incur some costs years ahead of when the costs are
recovered by sales. Manufacturers must allow time to design, test, evaluate,
certify, and produce the engine before sale. Typically, design work occurs in
the year before mechanical integrity testing and recalibration work. The
following year certification is undertaken. Production begins the year after
certification.
Table 3.7 shows these costs as they were accounted for in EPA's cost
estimate.
3.6.2. Accounting for Costs as They are Recovered
EPA assumes that costs which occur in years preceding production are
recovered over sales throughout the production cycle. For instance, EPA
assumes the annualized design cost for 1993 is recovered over 1996 sales.
Similarly, annualized design costs occurring in 1994 are recovered over 1997
sales. Therefore, the methodology attributes the first year of amortized costs to
the first year of sales, the second year of amortized costs to the second year of
sales, et cetera. These costs are shown in year of recovery in future value18
Table 3.8 shows the total costs which are recovered in each sales year
through fleet turn over in 2026.
3.6.3. Evaluation of the Stream of Costs
The stream of costs recovered over sales throughout the turn over of the
fleet must be analyzed in the present value19 of the yearly costs. The present
value of the recoverable costs is stated in Table 3.9 in 1992 dollars. The
methodology used to determine the present value is calculated according to
Agency guidance (i.e., the Kolb-Scheraga two-stage procedure).(12) Kolb-
Scheraga point out that the economics literature has established the social rate
of time preference as the appropriate rate for discounting the benefits and
18
Future value means the value at a future date of money that has been paid or received in pnor pen.si-
19
Present value means the value of money at a present date that will be paid or received in future p> n. >.i-
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DRAFT
costs of public projects, once they are expressed in terms of consumption
gained and foregone, and provide a procedure for doing this. According to
this methodology, capital costs are amortized and discounted at 10 percent.
Annualized capital costs are then added to operating costs (e.g., variable
hardware costs, administrative costs). The total cost stream is then discounted
at 3 percent to present value. This methodology is appropriate in this case
because capital costs imposed by this proposal are likely to be passed directly
through to consumers in the form of higher prices and thus reduce the
consumption of goods and services. This methodology is more appropriate in
this instance than simply discounting all costs at 10 percent. This is because
the two-stage procedure accounts for both displaced private investment (in the
annualization process) and foregone consumption (by discounting both costs
and benefits by the social rate of time preference).
Table 3.9 presents the total annualized stream of costs, the present value
stream of the total annualized costs, the increase in retail price, the present
value of the increase in retail price, and the per engine present value increase
in retail price. Further, Table 3.9 presents the present value per engine cost-
effectiveness in dollars per ton NOx reduced. The present value per engine
cost-effectiveness represents the annual cost discounted according to the Kolb-
Scheraga two-stage procedure, divided by the present value per engine
benefits discounted at 3 percent.
3.7. Cost-Effectiveness of the Proposed Rule
In evaluating various pollution control options EPA considers the
cost-effectiveness of the control. The cost-effectiveness of a pollution control
measure is typically expressed as the cost per ton of pollutant emissions
reduced. Other things being equal, EPA prefers to target emission reductions
that cost less per ton of emissions reduced.
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DRAFT 121
3.7.1. Cost Per Ton of NO, Reduction
The proposed NOx standard for large nonroad CI engines is estimated
to have a cost-effectiveness of $86 per ton of NOx removed from the exhaust of
the affected engines. This cost per ton of NOx reduction is based on the ratio
of the net present value of the stream of costs divided by the net present value
of the stream of benefits. The cost and benefit stream are calculated over the
30 years it takes the fleet to turn over.
The cost-effectiveness of the proposed rule on a per engine basis was
presented in Table 3.9. When cost-effectiveness is calculated on a per engine
basis, a different cost-effectiveness ratio is achieved. This is because yearly
sales and attrition do not enter the calculation. This is an important distinction
for mobile sources for two reasons. First, benefits are achieved on new engine
sales. This means that relatively small benefits are achieved in the beginning
years of an emission reduction regulation and that benefits increase throughout
the years as the fleet turns over. Second, it is inappropriate to compare per
engine benefits from this regulation to other regulatory programs. This is
because the source dynamics (e.g., sales, attrition, usage) of other emission
sources likely differ from the source dynamics of the engines under this
proposal.
It would be appropriate to compare the per engine cost-effectiveness for
different options for reducing emissions from the engines under this proposal
if the regulatory schedule and affected engines were identical between the
options. However, in order to understand and evaluate emission reductions
which occur over time it is appropriate to evaluate the net present value of the
stream of costs in comparison to the net present value of the stream of
benefits.
3.7.2. Comparison to Cost-Effectiveness of Other Emission Control Strategies
The cost-effectiveness of the proposed nonroad NOx standards may be
compared to other CAA measures that reduce NOx emissions. Title I of the
1990 Clean Air Act Amendments requires certain areas to provide for
-------
122 DRAFT
reductions in volatile organic compounds and NOx emissions as necessary to
attain the NAAQS for ozone. Title I specifically outlines provisions for the
application of reasonably available control technology (RACT) and new source
review (NSR) for major NOx emitters. In addition, EPA anticipates that more
stringent reductions in NOx emission will be necessary in certain areas. Such
reductions will be identified through dispersion modeling analyses required
under Title I. The cost-effectiveness of these measures is generally estimated
to be in the range of $100 to $5,000 per ton of NOx reduced.(13) In addition
to applying NOx control technologies to meet requirements under Title I of the
Clean Air Act, many point sources will also be required to meet NOx emission
rate limits set forth in other programs, including those established under Title
IV of the Act, which addresses acid deposition (i.e., acid rain). EPA anticipates
that the cost of complying with regulations required under section 407 of the
Clean Air Act (Nitrogen Oxides Emission Reduction Program), which proposes
nationwide limits applicable to NOx emission from coal-fired power plants,
will be between $200 and $250 per ton.
The cost-effectiveness of controlling NOx emission from on-highway
mobile sources has also been estimated. The Tier I NOx standard for light-
duty vehicles, which will be phased in starting in 1994, is estimated to cost
$3,490 per ton of NOx reduced. The 1998 heavy-duty highway engine NOx
standard is estimated to cost between $210 and $260 per ton of NOx reduced
and the recently proposed on-board diagnostics regulation is estimated to cost
$84 per ton of NOx reduced from malfunctioning in-use light-duty vehicles.
The cost-effectiveness of the VOC and NOx control measures discussed above
are summarized in Table 3.10 on page 129.
In summary, the cost-effectiveness of the standard included in the
current proposal is favorable relative to the cost-effectiveness of several other
NOx control measures required under the Clean Air Act. To the extent that
cost-effective nationwide controls are applied to large nonroad CI engines, the
-------
DRAFT 123
need to apply in the future more expensive additional controls to mobile and
stationary sources that also contribute to acid deposition, as well as ozone
nonattainment, nutrient loading, visibility, and particulate matter and nitrogen
dioxide nonattainment may be reduced.
Furthermore, the cost-effectiveness of the NOx control program
proposed here is also favorable relative to several mandated VOC control
measures. Because many state air quality planners will need to develop a mix
of programs to reduce both VOC and NOx in their nonattainment areas, the
overall cost of reducing ambient ozone will be dependent on the cost-
effectiveness of both VOC and NOx controls. Hence, cost-effective NOx control
programs such as the one proposed here should result in lower overall ozone
control costs. However, direct comparisons of dollar/ton estimates for NOx
and VOC control measures are difficult because the relationship between NOx,
VOC, and ambient ozone levels varies from area to area.
-------
DRAFT
Table 3-07
Annualized Costs as Incurred
Year
Variable
Hsdwve
Cost
Recaifarabon
Deagn
Test Facity
Mechanical
htegity
Testng
Averagrg
Bariong
and Tradrtg
Certficabon
Enussicn
Defect
Reporting
Sebcfre
Enforcement
Audi fag
knportatnn
Exdtarons
Exempfons
ANNUALIZED
TOTAL
1993
0
0
2,525.000
663,000
0
0
0
0
0
0
0
0
3,388,000
1994
0
2,174,000
2.525.000
663,000
1 733,000
0
0
0
0
0
0
0
7.295.000
1995
0
2,174,000
2,525,000
863 000
1 733 000
306,000
6,861 000
0
0
0
0
0
16,442,000
1996
16,277,000
2,174,000
2.525,000
863 000
1,733,000
306,000
8,945,000
13,000
1 605,000
34,000
3000
13000
34 441 000
1997
16,603000
2,174,000
2.525,000
663 000
1,733 000
306,000
8,945,000
13,000
1605,000
34 000
3000
13000
34,767 000
1996
16,935,000
21174.000
2,525,000
663 000
1,733,000
306,000
8,945,000
13,000
1 605,000
34,000
3000
13000
35,099.000
1999
17,274,000
a 174,000
2,525.000
663000
1 733,000
306,000
8945.000
13000
428.000
34,000
3000
13000
34.261,000
2000
17 619000
1174,000
2.525,000
663,000
1,733,000
306 000
8945,000
13,000
428,000
34,000
3000
13000
34,606000
2001
17,971 000
£174,000
2.525,000
663000
1 733 000
306 000
8945,000
13,000
428,000
34 000
3000
13000
34,958,000
2002
16 331 000
2,174000
2,525,000
663000
1 733 000
306 000
8,945 000
13,000
428,000
34,000
3000
13000
35316,000
2003
16 697 000
2,174000
0
863 000
1,733 000
306 000
B,945 000
13.000
428 000
34,000
3000
13000
33,159,000
2004
19 071000
2,174000
0
663 000
0
306 000
B,945,000
13 000
428,000
34,000
3000
13000
31 800,000
2005
19453 000
2,174000
0
663 000
0
306,000
8,945 000
13000
428,000
34 000
3000
13000
32162,000
2006
19,642.000
Z174000
0
663 000
0
306,000
8,945 000
13,000
428,000
34,000
3000
13000
32,571,000
2007
20239.000
£174,000
0
863,000
0
306,000
8,945 000
13,000
428,000
34,000
3000
13000
32.968.000
2006
20 643 000
2,174,000
0
863,000
0
306000
8 945 000
13000
428000
34,000
3000
13000
33 372.000
2009
21056000
£174,000
0
663000
0
306 000
8,945 000
13,000
428,000
34 000
3000
13000
33 765,000
2010
21 477 000
2,174000
0
663,000
0
306 000
8,945000
13,000
426,000
34,000
3000
13000
34,206,000
2011
21907 000
2,174 000
0
663000
0
306 000
8,945000
13,000
428.000
34,000
3000
13000
34 636,000
2012
22 345000
2,174,000
0
663,000
0
306 000
B945000
13000
426,000
34,000
3000
13000
35 074 000
2013
22792,000
2,174000
0
663000
0
306 000
8945,000
13000
428,000
34,000
3000
13000
35 521000
124
-------
DRAFT
125
Table 3-07
(cont.)
Y
-------
DRAFT
Table 3-08
Annualized Costs as Recovered
Yur
Variable
tisAvao
Cost
Roca&brsSon
Desp
Test Facirfy
Uecfarueal
htegnty
Testvig
Averaging
Barfang
and Tradug
Certficafcon
EmissMft
Defect
Raportng
Selective
Enter cement
Audtng
knpcrtabon
Exduaore
Exempton*
ANNUALIZED
TOTAL
1996
16277000
2,306,397
2,759,136
943,023
1,836540
315,160
9,147,430
13,000
666,000
34,000
3,000
13000
34265705
1997
16,600,000
2,306,397
2,759,136
943 023
1 838540
315,160
9^13,350
13 000
1 605000
34,000
3,000
13,000
35,596,625
1996
16,935,000
2,306,397
2,759,136
943023
1,838,540
315,180
9213,350
13,000
1,605000
34000
3,000
13,000
35,928.625
1999
17,274,000
2.306,397
2,759136
943,023
1 838,540
315,180
9,213 350
13 000
1,605,000
34,000
3,000
13,000
36287,625
2000
17,619000
2,306,397
2.759136
943,023
1 838,540
315,180
9.213,350
13,000
1605,000
34,000
3.000
13000
36,612.625
2001
17,971000
2.306.397
2.759,136
943,023
1,838,540
315,180
9.213.350
13,000
1,605,000
34,000
3000
13000
36.964.62S
2002
16331000
Z306.397
2.759,136
943,023
1,838,540
315,180
9,213.350
13,000
1,605000
34,000
3,000
13,000
37,324,625
2003
16697000
2,306,397
2.759136
943,023
1,838,540
315,180
9,213,350
13,000
1,605,000
34,000
3000
13000
37 690,625
2004
19,071 000
2,306,397
2,759136
943,023
1,838 540
315,180
9,213,050
13,000
1,605,000
34 000
3,000
13,000
38,064,625
2006
19,453 000
a 306 397
2,759136
943,023
1,838 540
315,180
9,213 350
13 000
1605,000
34,000
3,000
13,000
38,446,625
2006
19 642,000
a306 397
0
943023
0
315180
9213,350
13 000
1605,000
34,000
3000
13,000
34237,950
2007
20239 000
2,306 397
0
943 023
0
315160
9213350
13 000
1,605,000
34 000
3000
13 000
34,634950
2006
20 643 000
2,306 397
0
943023
0
315180
9213 350
13 000
1605,000
34,000
3,000
13,000
35,038 950
2009
21 056 000
2.306 397
0
943023
0
315180
9,213 350
13 000
1605,000
34 000
3.000
13,000
35451 950
2010
21 477000
2.306 397
0
943023
0
315180
9,213,350
13,000
1605000
34,000
3,000
13000
35,872,950
2011
21,907,000
2,306,397
0
943,023
0
315180
9213,350
13,000
1605000
34,000
3000
13000
36,302.950
2012
22 345 000
2.306,397
0
943,023
0
315180
9213,350
13 000
1605,000
34,000
3000
13,000
36,740950
2013
22 792000
£306 397
0
943 023
0
315180
9,213.350
13,000
1,605000
34,000
3000
13,000
37,187 950
2014
23248000
2,306,397
0
943023
0
315180
9213 350
13,000
1,605000
34 000
3000
13,000
37,643 950
2015
23 713 000
a306 397
0
943023
0
315,180
9213 350
13,000
1 605,000
34 000
3,000
13,000
38,106,950
2016
24167 000
2.306.397
0
943023
0
315,180
9,213,350
13000
1,605,000
34 000
3,000
13,000
38582,950
126
-------
DRAFT
Table 3-08
(cont.)
Yoar
VaraU*
Hardar«0
Cost
Racattrrton
Doagri
Test Fadity
UodurucaJ
htaprty
Testng
Avaragrtg
Banking
and Tradfig
fartficatnn
Emission
Defect
Reportng
SetocOve
Enforcement
AwSlng
kn periston
Exduscns
Exemplons
ANNUALIZED
TOTAL
2017
24.671.000
2,306 397
0
943,023
0
315180
9,213 350
13000
1,605000
34000
3 000
13,000
39,066,950
2018
25 164 000
Z306.397
0
943,023
0
315,180
9,213,350
13000
1605,000
34 000
3,000
13,000
39,559650
2019
25 668 000
2,306,397
0
943 023
0
315180
9,213 350
13,000
1,605000
34 000
3000
13,000
40,063,950
2020
26161000
2,306,397
0
943,023
0
315180
9,213,350
13 000
1,605,000
34 000
3 000
13 000
40,576,950
2021
26,706000
Z30B397
0
943,023
0
315180
9213 350
13,000
1,605000
34000
3,000
13,000
41 100950
2022
27.239 000
Z306.397
0
943 023
0
315180
9,213,350
13.000
1,605,000
34000
3.000
13,000
41,634,950
2023
27 783 000
£306 397
0
943 023
0
315180
9213 350
13000
1 605000
34,000
3000
13,000
42,176,950
2024
28339000
2.306 397
0
943 023
0
315180
9,213350
13000
1605,000
34000
3000
13000
42 734 950
2025
28 906 000
2.306 397
0
943 023
0
315160
9213 350
13,000
1605000
34000
3,000
13000
43,301 950
2026
29 484 000
Z306 397
0
943 023
0
315180
9,213,350
13 000
1,605,000
34000
3000
13,000
43,879,950
127
-------
128
DRAFT
Table 3-09
Annualized Costs and Corresponding Present Values
Year
Annualized
Total
(1992$)
Present Value
of
Annualized Total
(1992$)
Total Increase in
Retail Cost
(1992$)
Present Value of
Total Increase in
Retail Cost
(1992$)
Present Value
Per Engine
Increase in Retail Cost
(1992$)
Present Value
Per Engine
Cost-Effectiveness
in Dollars per Ton
of NOx Reduced
(1992$)
1996
34,205,705
30,015,000
39,992,000
35,011,000
110
54
1997
35,596,625
" 30,255,000
41,456,000
35,236,000
108
55
1998
35,928,625
29,648,000
41,882,000
34,561,000
104
54
1999
36,267,625
29,056,000
42,316,000
33,902,000
100
54
2000
36,612,625
28,478,000
42,759,000
33,259,000
96
53
2001
36,964,625
27,915,000
43,210,000
32.631,000
93
53
2002
37,324,625
27,366,000
43,672,000
32,019,000
89
52
2003
37,690,625
26,829,000
44,141,000
31,421,000
86
52
2004
38,064,625
26,306,000
44,620,000
30,836,000
82
51
2005
38,446,625
25,796,000
45,110,000
30,267,000
79
51
2006
34,237,950
22,303,000
40,726,000
26,530,000
68
45
2007
34,634,950
21,905,000
41,235,000
26,079,000
66
45
2008
35,038,950
21,515,000
41,753,000
25,637,000
63
44
2009
35,451,950
21,134,000
42,282,000
25,206.000
6t
44
2010
35,872,950
20,762,000
42,822,000
24,784,000
59
44
2011
36,302,950
20,399,000
43,373,000
24,372,000
57
43
2012
36,740,950
20,044,000
43,935,000
23,969,000
55
43
2013
37,187,950
19,697,000
44,508,000
23,574 000
53
43
2014
37,643,950
19,358,000
45,092,000
23,188,000
51
42
2015
38,108,950
19,026,000
45,689,000
22,811.000
49
42
2016
38,582,950
18,702,000
46,296,000
22,440,000
47
42
2017
39,066,950
18,385,000
46,917,000
22.079000
46
42
2018
39,559,950
18,075,000
47,549,000
21,725,000
44
41
2019
40,063,950
17,772,000
48,195,000
21,379,000
42
41
2020
40,576,950
17,475,000
48,853,000
21,039,000
41
41
2021
41,100,950
17,185,000
49,524,000
20,707,000
40
41
2022
41,634,950
16,901,000
50,209,000
20,382,000
38
40
2023
42,178,950
16,624,000
50,906,000
20,063,000
37
40
2024
42,734,950
16,352,000
51,619,000
19,751,000
36
40
2025
43,301,950
16.086,000
52,346,000
19,446,000
34
40
2026
43,879,950
15,826,000
53,087,000
19,147,000
33
39
-------
DRAFT
Table 3-10
Cost-Effectiveness of Several NOx Control Measures
Control Measure
Cost-Effectiveness
($/ton)
Tier I NO, Standard (LDVs)
3,490
Title I Stationary Source Control
100-5,000
Heavy Duty Diesel Standard (1998 On-Highway)
210-260
Title IV Stationary Source Control
200-250
On Board Diagnostics (LDVs)
1,974
Large Nonroad CI Engine Standards
86
-------
DRAFT
-------
DRAFT
Chapter 3: References
1. U.S. Department of Labor, Bureau of Labor Statistics, Outlook:
1990-2005, BLS Bulletin 2402, May 1992.
2. U.S. Department of Labor, Bureau of Labor Statistics, Outlook:
1990-2005, BLS Bulletin 2402, May 1992.
3. U.S. Department of Labor, Bureau of Labor Statistics, Outlook:
1990-2005, BLS Bulletin 2402, May 1992.
4. U.S. Department of Labor, Bureau of Labor Statistics, Outlook:
1990-2005, BLS Bulletin 2402, May 1992.
5. Statement for Information Collection Request, Control of Air Pollution
from New Nonroad Mobile Source Engines, Proposed Regulations for 1996 and Later
Model Year Nonroad Compression-Ignition Engines At or Above 50 Horsepower,
Amending Application for Motor Vehicle Emission Certification and Fuel Economy
Labelling (OMB No. 2060-0104) EPA No. 783, October 1992.
6. Statement for Information Collection Request, Control of Air Pollution
from New Nonroad Engines, Proposed Regulations for 1996 and Later Model Year
Nonroad Engines, Application for Averaging, Banking, and Trading Program
Reporting and Recordkeeping (OMB No. 2060-0104), EPA No. 783, September
1992.
7. McCarthy, John H., Study of the Significance of NOx Deterioration
Factors in Proposed Regulation of Nonroad Compression-Ignition Cycle Engines
Greater Than or Equal to 50 Horsepower, EPA Memorandum Date December 20,
1991.
131
-------
132
DRAFT
8. Statement for Information Collection Request, Control of Air Pollution
from New Nonroad Engines, Proposed Regulations for 1995 and Later Model Year
Nonroad Engines, Amending Application for Motor Vehicle Emission Defect
Information Report and Records (OMB No. 2060-0048) EPA No. 0282, July 1992,
page 10.
9. Statement for Information Collection Request, Control of Air Pollution
from New Nonroad Engines, Proposed Regulations for 1996 and Later Model Year
Nonroad Engines, Application for Selective Enforcement Auditing Reporting and
Recordkeeping (OMB Control No. 2060-0064), EPA No. 11, September 1992.
10. Jack Faucett Associates, Update of EPA's motor Vehicle Emission
Control Equipment Retail Price Equivalent (RPE) Calculation Formula (JACKFAU-
85-322-3), September 1985.
11. Navistar International, Application for Certification 1992 Navistar
Heavy Duty Diesel Engine Families, Section 06.01-3.
12. U.S. Environmental Protection Agency, Office of Policy, Planning,
and Evaluation, Guidelines for Performing Regulatory Impact Analyses, Appendix
C, EPA-230-01-84-003, March 1991, Washington, DC.
13. The Clean Air Act Section 183(d) Guidance on Cost-Effectiveness,
EPA-450/2-91-008, November 1991.
-------
DRAFT
Appendix A: Supplementary Tables
for
Chapter 1
133
-------
134 DRAFT
Table A-01
Inventory A
Equipment Populations, Horsepower Ratings, Load Factors,
Average Annual Hours of Use, NOx Emission Factors
Equipment Types
Population
Hrs/Year
Avg. HP
Load
Factor
Baseline
g/hp-hr NOx
Concrete/Industrial Saws
135
487
56
73%
11.0
Other Agricultural Equipment
18,042
330
57
51%
11.1
Wood Splitters
79
81
58
50%
8.0
Trenchers
50,510
522
60
75%
10.0
Balers
4,260
93
74
58%
78
T ractors/Loaders/Backhoes
299,265
1,004
77
55%
101
Swathe rs
50,032
89
79
55%
11.5
ForWifts "
160,583
1,607
83
30%
14.0
Asphalt Pavers
15,536
681
91
62%
10.3
Sprayers
9,692
88
92
50%
7.8
Rough Terrain Forklifts
53,853
569
93
60%
80
Terminal Tractors **
64,598
1,200
96
82%
140
Sweepers/Scrubbers
36,977
1,244
97
68%
140
Agricultural Tractors
2,519,295
411
98
70%
11.2
Chippers/Stump Grinders
17,087
437
99
37%
8.0
Paving Equipment
43,615
507
99
53%
11.0
Rollers
36,300
626
99
56%
93
Total 50-100 HP
3,379,859
Other General Industrial
Equipment
18,366
812
107
51%
14.0
Other Matenal Handling
Equipment
5,258
406
111
59%
14.0
Crushing/Proc Equipment
7,207
840
127
78%
11.0
Concrete Pavers
5,511
665
130
68%
10.0
Aircraft Support Equipment
9,529
732
137
51%
140
Skidders
30,911
1,158
150
74%
11.3
-------
DRAFT
135
Table A-01
(cont.)
Equipment Types
Population
Hrs/Year
Avg. HP
Load
Factor
Baseline
g/hp-hr NO,
Combines
284,854
124
152
70%
11.5
Crawler Tractors
285,923
847
157
58%
103
Rubber Tired Loaders
209,454
723
158
54%
10.3
Other Construction Equipment
11,867
500
161
62%
110
Graders
70,045
686
172
61%
96
Total 100-175 HP
938,925
Excavators
61,336
747
183
57%
10 8
Fellers/Bunchers
15,581
1,110
183
71%
11.3
Cranes
98,357
701
194
43%
103
Bore/Drill Rigs
7,761
389
209
75%
11.0
Off-Highway Tractors
38,921
859
214
65%
119
Scrapers
26,700
823
311
72%
8.7
Rubber Tired Dozers
7,757
818
356
59%
96
Off-Highway Trucks
16,529
1,502
489
57%
9.6
Total >175 HP
272,942
Total
4,591,726
-------
136 DRAFT
Table A-02
Inventory B
Equipment Populations, Horsepower Ratings, Load Factors,
Average Annual Hours of Use, NOx Emission Factors
Equipment Types
Population
Hrs/Year
Avg. HP
Load
Factor
Baseline
g/hp-hr NO„
Concrete/Industrial Saws
61,336
487
56
73%
11.0
Other Agricultural Equipment
18,042
330
57
51%
11.1
Wood Splitters
79
81
58
50%
8.0
T ractors/Loaders/Backhoes
189,000
700
71
38%
101
Asphalt Pavers
12,000
814
77
56%
10.3
Concrete Pavers
8,400
814
77
56%
10 0
Swathers
50,032
100
82
62%
11 5
Forkhfts -
47,068
850
83
30%
14 0
Rough Terrain Forklrfts
25,132
873
84
35%
8.0
Sprayers
9,692
88
92
50%
7.8
Terminal Tractors"
64,598
1,200
96
82%
140
Sweepers/Scrubbers
36,977
1,244
97
68%
140
Balers
4,260
308
98
58%
78
Agricultural Tractors
2,519,295
411
98
70%
11 2
Chippers/Stump Grinders
17,087
437
99
37%
8.0
Paving Equipment
43,615
507
99
53%
11.0
Rollers
42,800
682
99
59%
9.3
Total 50-100 HP
3,149,413
Other General Industrial
Equipment
18,366
812
107
51%
140
Other Matenal Handling
Equipment
5,258
406
111
59%
14.0
Crushing/Proc Equipment
7,207
840
127
78%
11.0
Skidders
30,911
1,398
131
49%
11 3
Crawler Tractors
159,050
1,021
134
57%
103
Aircraft Support Equipment
9,529
732
137
51%
140
-------
DRAFT
137
Table A-02
(cont.)
Equipment Types
Population
Hrs/Year
Avg. HP
Load
Factor
Baseline
g/hp-hr NO,
Excavators
52,295
1,190
143
59%
10.8
Graders
64,000
924
147
54%
96
Combines
284,854
124
152
70%
11.5
Other Construction Equipment
11,867
500
161
62%
11 0
Total 100-175 HP
643,337
Rubber Tired Loaders
130,000
1,398
175
54%
10 3
Fellers/Bunchers
.15,581
1,110
183
71%
11.3
Cranes
98,357
701
194
43%
103
Bore/Drill Rigs
7,761
389
209
75%
11.0
Off-Highway Tractors
38,921
859
214
65%
11 9
Scrapers
16,400
1,385
290
60%
87
Rubber Tired Dozers
7,757
818
356
59%
96
Off-Highway Trucks
19,400
3,293
658
25%
96
Total >175 HP
334,177
Total
4,126,927
-------
138
DRAFT
Table A-03
50-100 HP
Nationwide Engine Population,
Baseline and Controlled Annual Per-Engine Emissions
Nationwide
Population
Annual Per-Source NO, (tons)
Baseline
Controlled
Inventory A
3,380,000
0.39
0 24
Inventory B
3,149,000
0 36
0.22
Average
3,265,000
0 38
0.23
Table A-04
100-175 HP
Nationwide Engine Population,
Baseline and Controlled Annual Per-Engine Emissions
Nationwide
Population
Annual Per-Source NO, (tons)
Baseline
Controlled
Inventory A
939,000
063
0.41
Inventory B
643,000
0 58
0 37
Average
791,000
060
0 39
Table A-05
175 and greater HP
Nationwide Engine Population,
Baseline and Controlled Annual Per-Engine Emissions
Nationwide
Population
Annual Per-Source NO, (tons)
Baseline
Controlled
Inventory A
273,000
1 29
1--.
GO
O
Inventory B
334,000
155
105
Average
304,000
1 42
0 96
-------
DRAFT
Table A-06
50 and Greater HP
Nationwide Engine Population,
Baseline and Controlled Annual Per-Engine Emissions
Nationwide
Population
Annual Per-Source NO, (tons)
Baseline
Controlled
Inventory A
4,592,000
0.50
0 31
Inventory B
4,127,000
0.49
0.31
Average
4,359,000
0 49
031
-------
Enq
DRAFT
Table A-07
ine Survival Rate and Relative Usage vs Age
Age
Survival Probability
Relative Usage
1
100%
120%
2
98%
120%
3
96%
120%
4
94%
120%
5
92%
120%
6
90%
120%
7
88%
120%
8
86%
112%
9
84%
103%
10
80%
95%
11
75%
86%
12
70%
86%
13
65%
86%
14
60%
86%
15
55%
86%
16
50%
86%
17
45%
82%
18
40%
77%
19
35%
73%
20
30%
69%
21
27%
64%
22
24%
60%
23
21%
60%
24
18%
60%
25
15%
60%
26
12%
60%
27
9%
60%
28
6%
60%
29
4%
60%
30
2%
60%
-------
DRAFT
141
Table A-08
Diesel Engine Consumption
Estimates and Projections 1960-2026
Year
DOC Figures (All Nonhighway Diesels)
EPA Estimates and Projections
Apparent
Consumption
Total
Engines
Produced
Apparant +
"Internal"
Consumption
Apparant +
"Internal"
Consumption
(All Non-Highway
Diesels)
Total U S.
Consumption ol
Nonroad CI Engines
Over 50 HP
2026
578,118
2025
566,782
2024
555,669
2023
544,773
2022
534,091
2021
523,619
2020
513,352
2019
503,286
2018
493,418
2017
483,743
2016
474,258
2015
464,959
2014
455,842
2013
446,904
2012
438,141
2011
429,550
2010
421,127
2009
412,870
2008
404,775
2007
396,838
2006
389,057
2005
381,428
2004
373,949
2003
366,617
-------
142
DRAFT
Table A-08
(cont.)
Year
DOC Figures (All Nonhighway Diesels)
EPA Estimates and Projections
Apparent
Consumption
Total
Engines
Produced
Apparent +
"Internal"
Consumption
Apparent +
"Internal"
Consumption
(All Non-Highway
Diesels)
Total U.S.
Consumption of
Nonroad CI Engines
Over 50 HP
2002
359,428
2001
352,381
2000
345,471
1999
338,697
1998
332,056
1997
325,545
1996
319,162
1995
312,904
1994
306,768
1993
300,753
1992
294,856
1991
289,075
1990
364,400
199,905
382,841
382,841
267,989
1989
415,837
217,456
443,087
443,087
310,161
1988
388,726
212,720
422,696
422,696
295,887
1987
318,597
167,804
344,405
344,405
241,084
1986
331,088
160,755
356,272
356,272
249,390
1985
300,198
173,258
326,341
326,341
228,439
1984
293,953
211,019
328,901
328,901
230,231
1983
211,160
169,552
238,407
238,407
166,885
1982
255,442
209,496
289,127
289,127
202,389
1981
422,327
349,262
475,984
475,984
333,189
1980
418,345
344,119
472,606
472,606
330,824
1979
383,108
478,584
335,009
-------
DRAFT
143
Table A-08
(cont.)
Year
DOC Figures (All Nonhighway Diesels)
EPA Estimates and Projections
Apparent
Consumption
Total
Engines
Produced
Apparant +
"Internal*
Consumption
Apparant +
"Internal"
Consumption
(All Non-Highway
Diesels)
Total U S.
Consumption of
Nonroad CI Engines
Over 50 HP
1978
436,251
388,438
436,251
436,251
305,376
1977
367,039
467,599
327,319
1976
315,274
432,211
302,548
1975
335,116
445,776
312,043
1974
352,429
457,611
320,328
1973
309,549
428,297
299,808
1972
259,274
393,928
275,750
1971
219,344
366,631
256,642
1970
225,853
371,081
259,756
1969
253,732
390,139
273,098
1968
251,869
388,866
272,206
1967
252,452
389,264
272,485
1966
254,489
390,657
273,460
1965
245,598
384,579
269,205
1964
263,927
1963
258,752
1962
253,678
1961
248,704
1960
243,827
-------
DRAFT
Table A-09
Projected Total Nonroad CI Engine Population
1990-2026
Year
Total Population
All
<100HP
100-175HP
>175HP
2026
7,653,005
5,731,223
1,388,868
532,913
2025
7,502,946
5,618,846
1,361,636
522,464
2024
7,355,829
5,508,673
1,334,937
512,219
2023
7,211,598
5,400,660
1,308,762
502,176
2022
7,070,194
5.294,764
1,283,100
492,329
2021
6,931,562
5,190,946
1,257,941
482,676
2020
6,795,649
5,089,162
1,233,275
473,212
2019
6,662,093
4,989,144
1,209,038
463,911
2018
6,531,796
4,891,566
1,185,391
454,838
2017
6,404,529
4,796,258
1,162,295
445,976
2016
6,279,101
4,702,326
1,139,532
437,242
2015
6,156,208
4,610,294
1,117,230
428,684
2014
6,035,400
4,519,822
1,095,305
420,272
2013
5,916,269
4,430,607
1,073,685
411,976
2012
5,797,737
4,341,841
1,052,174
403,723
2011
5,680,408
4,253,974
1,030,881
395,552
2010
5,567,015
4,169,056
1,0)0,303
387,656
2009
5,456,976
4,086,650
990,333
379,994
2008
5,350,519
4,006,925
971,013
372,581
2007
5,249,408
3,931,205
952,663
365,540
2006
5,153,975
3,859,737
935,344
358,894
2005
5,062,869
3,791,508
918,810
352,550
2004
4,976,342
3,726,709
903,107
346,525
2003
4,894,551
3,665,458
888,264
340,830
2002
4,817,061
3,607,426
874,201
335,434
-------
DRAFT
Table A-09
(cont)
Year
-Total Population
All
<100HP
100-175HP
>175HP
2001
4,742,401
3,551,515
860,652
330,235
2000
4,671,161
3,498,164
847,723
325,274
1999
4,605,991
3,449,359
835,896
320,736
1998
4,547,195
3,405,327
825,226
316,642
1997
4,494,648
3,365,976
815,689
312,983
1996
4,447,094
3,330,363
807,059
309,671
1995
4,405,958
3,299,557
799,594
306,807
1994
4,371,663
3,273,875
793,370
304,419
1993
4,344,341
3,253,413
788,412
302,516
1992
4,324,464
3,238,527
784,804
301,132
1991
4,312,074
3,229,249
782,556
300,269
1990
4,307,452
3,225,788
781,717
299,947
-------
DRAFT
Table A-10
Projected Controlled Nonroad CI Engine Population
1990-2026
Year
Controlled Population
All
<100HP
100-175HP
>175HP
2026
7,648,129
5,726,347
1,388,868
532,913
2025
7,487,255
5,604,314
1,360,477
522,464
2024
7,323,066
5,479,798
1,331,484
511,784
2023
7,153,188
5,350,409
1,301,902
500,877
2022
6,977,154
5,216,244
1,271,161
489,749
2021
6,794,866
5,077,395
1,239,286
478,185
2020
6,606,447
4,933,955
1,206,298
466,194
2019
6,412,017
4,786,014
1,172,219
453,785
2018
6,211,695
4,633,659
1,137,071
440,965
2017
6,005,595
4,476,978
1,100,874
427,743
2016
5,793,832
4,316,056
1,063,650
414,126
2015
5,571,639
4,146,098
1,025,417
400,123
2014
5,338,063
3,967,284
985,039
385,741
2013
5,092,893
3,779,786
942,555
370,551
2012
4,836,354
3,583,774
898,009
354,570
2011
4,568,670
3,379,417
851,440
337,813
2010
4,290,059
3,166,876
802,889
320,294
2009
4,000,736
2,946,313
752,393
302,030
2008
3,700,911
2,717,885
699,991
283,035
2007
3,390,789
2,481,746
645,721
263,322
2006
3,070,573
2,238,047
589,618
242,907
2005
2,742,898
1,989,375
531,720
221,802
2004
2,413,366
1,740,704
472,640
200,022
2003
2,083,389
1,492,032
413,560
177,797
2002
1,753,412
1,243,360
354,480
155,573
-------
DRAFT
Table A-10
(cont)
Year
Controlled Population
All
<100HP
100-175HP
>175HP
2001
1,423,436
994,688
295,400
133,348
2000
1,093,459
746,016
236,320
111,123
1999
763,483
497,344
177,240
88,899
1998
433,506
248,672
118,160
66,674
1997
103,529
0
59,080
44,449
1996
22,225
0
0
22,225
1995
0
0
0
0
1994
0
0
0
0
1993
0
0
0
0
1992
0
0
0
0
1991
0
0
0
0
1990
0
0
0
0
-------
DRAFT
Table A-11
Projected Annual Nationwide Nonroad CI NOx Emissions
1990-2026, Baseline Scenario
Year
Baseline Annual NO, Emissions (tons)
All
<100HP
100-175HP
>175HP
2026
3,945,678
2,274,245
877,442
793,991
2025
3,868,312
2,229,652
860,238
778,423
2024
3,792,463
2,185,933
843,370
763,160
2023
3,718,101
2,143,071
826,833
748,196
2022
3,645,197
2,101,050
810,621
733,525
2021
3,573,722
2,059,853
794,727
719,142
2020
3,503,649
2,019,464
779,144
705,042
2019
3,434,859
1,979,814
763,846
691,199
2018
3,367,607
1,941,051
748,891
677,666
2017
3,301,815
1,903,129
734,260
664,426
2016
3,237,118
1,865,838
719,872
651,407
2015
3,173,712
1,829,292
705,772
638,648
2014
3,111,454
1,793,407
691,927
626,120
2013
3,050,211
1,758,107
678,308
613,796
2012
2,989,654
1,723,203
664,841
601,610
2011
2,929,874
1,688,747
651,547
589,580
2010
2,871,894
1,655,328
638,654
577,913
2009
2,815,528
1,622,839
626,119
566,571
2008
2,760,587
1,591,171
613,901
555,515
2007
2,707,686
1,560,680
602,137
544,869
2006
2,656,833
1,531,369
590,828
534,636
2005
2,607,716
1,503,058
579,905
524,752
2004
2,559,605
1,475,328
569,207
515,071
2003
2,512,630
1,448,252
558,760
505,618
2002
2,467,754
1,422,386
548,781
496,588
-------
DRAFT
Table A-11
(cont)
Year
Baseline Annual NO, Emissions (tons)
All
<100HP
100-175HP
>175HP
2001
2,424,460
1,397,431
539,153
487,876
2000
2.382,789
1,373,413
529,886
479,490
1999
2,345,160
1,351,724
521,518
471,918
1998
2,312,538
1,332,921
514,264
465,353
1997
2,283,264
1,316,048
507,754
459,463
1996
2,256,469
1,300,604
501,795
454,071
1995
2,230,445
1,285,603
496,008
448,834
1994
2,205,738
1,271,362
490,513
443,862
1993
2,182,411
1,257,917
485,326
439,168
1992
2,160,877
1,245,505
480,537
434,835
1991
2,146,231
1,237,063
477,280
431,887
1990
2,139,061
1,232,931
475,686
430,445
-------
DRAFT
Table A-12
Projected Annual Nationwide Nonroad CI NOx Emissions
1990-2026, With Controls
Year
Controlled Annual NO, Emissions
tons)
All
<100HP
100-175HP
>175HP
2026
2,485,320
1,378,555
570,987
535,778
2025
2,437,611
1,352,400
559,938
525,272
2024
2,391,544
1,327,197
549,253
515,094
2023
2,347,306
1,303,145
538,924
505,237
2022
2,304,933
1,280,221
529,018
495,694
2021
2,264,451
1,258,405
519,526
486,521
2020
2,225,823
1,237,673
510,441
477,709
2019
2,188,919
1,217,952
501,734
469,234
2018
2,154,364
1,199,759
493,460
461,145
2017
2,122,282
1,183,132
485,726
453,425
2016
2,092,519
1,167,938
478,478
446,103
2015
2,065,960
1,154,933
471,786
439.242
2014
2,042,827
1,144,161
465,833
432,833
2013
2,023,335
1,135,672
460,634
427,029
2012
2,006,573
1,128,619
456,156
421,798
2011
1,992,425
1,123,031
452,200
417,194
2010
1,981,704
1,119,479
448,985
413,240
2009
1,974,193
1,117,836
446,464
409,893
2008
1,969,671
1,117,974
444,588
407,109
2007
1,971,071
1,122,577
443,488
405,007
2006
1,979,422
1,131,895
443,945
403,582
2005
1,994,978
1,145,587
445,973
403,418
2004
2,016,333
1,162,541
449,357
404,435
2003
2,040,656
1,180,149
453,892
406,615
2002
2,067,820
1,198,966
458,893
409,960
2001
2,096,566
1,218,696
464,247
413,623
-------
DRAFT
Table A-12
(conl)
Year
Controlled Annual NO, Emissions
tons)
All
<100HP
100-175HP
>175HP
2000
2,126,936
1,239,361
469,961
417,613
1999
2,161,347
1,262,356
476,575
422,417
1998
2,200,766
1,288,237
484,301
428,227
1997
2,243,532
1,316,048
492,772
434,712
1996
2,244,094
1,300,604
501,795
441,695
1995
2,230,445
1,285,603
496,008
448,834
1994
2,205,738
1,271,362
490,513
443,862
1993
2,182,411
1,257,917
485,326
439,168
1992
2,160,877
1,245,505
480,537
434,835
1991
2,146,231
1,237,063
477,280
431,887
1990
2,139,061
1,232,931
475,686
430,445
-------
DRAFT
-------
DRAFT
Appendix B: Formation and Control of Pollutants
B.1. Oxides of Nitrogen. NO.
At high temperatures and pressures, normally inert nitrogen combines
with the oxygen in the air to form NO and N02. Combustion affects this
process only by altering the pressure and temperature in the cylinder. Since
the oxygen and nitrogen content of the air inducted by an engine cannot be
controlled, the only two physical factors that can be controlled to control NO,
emissions are temperature and the time the nitrogen and oxygen are exposed
to high temperatures. Strategies which enable the combustion to be completed
quickly effectively shorten the time for NOx formation and tend to reduce HC
and PM emissions as well. However those same strategies may also increase
the combustion temperature. Since NOx formation is a much stronger function
of temperature than time, the majority of NOx formation is accomplished in the
initial, uncontrolled, stage of combustion (detonation) and it is important to
reduce the temperature spike formed from detonation by such methods as
retarding the start of fuel injection, using a slower injection rate at the initial
injection period, using of higher cetane fuel, increasing the amount of air in the
cylinder, using of EGR, or some other method.
153
-------
154
DRAFT
B.2. Hydrocarbons
When hydrocarbons are heated to a high enough temperature in the
presence of oxygen, they turn into oxides of carbon and hydrogen. If
hydrocarbons appear in the exhaust of a properly operating engine they are
the result of molecules either hidden away from the air, or molecules that have
been cooled to a temperature too low for the reaction to take place in the
amount of time available. One of these two situations occurs under many
circumstances, such as the following.
• Fuel droplet size is too large. Combustion takes place on the
surface of the droplet only and as the fuel is consumed more
molecules are available for combustion. If the drop size is too
large the internal molecules never get to see any air and never get
a chance to burn.
• Fuel sprayed on combustion chamber walls. Assuming a
normally cooled surface, fuel impinging on the wall will be too
cool to burn even though there is plenty of air.
• Fuel dribbling from nozzle tip. Drop size is large and fuel may be
introduced at the wrong time in the cycle.
• Lubricating oil passing the piston rings, the intake valve guides,
and the turbine seals is cold and sees very little oxygen because it
is not atomized.
• Poor mixing, or too low air/fuel ratio. As fuel is introduced into
the cylinder it must find unused oxygen. If some of it finds only
combustion products, it will not bum.
B.3. Carbon Monoxide (CO)
When the hydrocarbon fuel burns it forms, among other things, CO.
Unlike HC which is typically a liquid, or Carbon ( C ) which is a solid, CO is a
gas which readily mixes and combines with available oxygen to form C02. An
Otto cycle engine can and at times does, operate at an air/fuel ratio that
supplies insufficient oxygen for complete combustion. CO formation can be a
problem under those conditions. The richest air/fuel ratio found in a diesel-
fueled compression-ignition engine is about 50% leaner than a Otto cycle
engine and much leaner still at part load. With all this excess oxygen available,
CO tends not to be a problem in diesel-fueled compression-ignition engines.
-------
DRAFT 155
B.4. Particulates and Smoke
Although there is not a one to one correspondence, smoke and
particulate are related. Smoke is the visible portion of particulate emissions
and generally the conditions which generate one generate the other.
Particulates are formed during the combustion process and they are oxidized
to gases during the expansion stroke after combustion is complete. Some
particulates, such as ash, cannot be oxidized. Some strategies for reducing
particulates are ending combustion sooner, using better fuels (lower ash and
lower sulfur), improving atomization, using a leaner air/fuel ratio.
-------
DRAFT
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DRAFT
Appendix C: EPA/EMA Engine Test Program
At the start of the rulemaking process, the following three important
questions had to be answered.
• At what level are current production nonroad engines polluting
the atmosphere?
• What test procedure should be adopted to simulate the real
world operation of these engines?
• What level of emission standards can be tolerated without putting
undue strain on either the engine manufacturers, the equipment
manufacturers or on the end users of the equipment?
To help answer these questions a test program was devised. Five engine
manufacturers agreed to supply one engine each which represented current
production nonregulated engines. Test data from these engines would be used
along with the data supplied by EMA to determine the current emission levels.
To meet the proposed emission standards it is likely that engine manufacturers
would apply emission control technologies similar to some of the technologies
used to meet the 1990 on-highway engine emission standards. Therefore, the
same five manufacturers agreed to supply an engine that was the same basic
engine model but would meet the 1990 MY on-highway emission standards
and develop about the same performance. Four of these engines were to be
comparable on-highway 1990 MY versions of the nonroad engines and the fifth
was to be a prototype. These five pairs of engines were then to be tested in
three different laboratories, two pairs at the EPA National Vehicle and Fuel
157
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158 DRAFT
Emission Lab in Michigan, two pairs at Southwest Research Institute in Texas
and the Detroit Diesel engine pair at Detroit Diesel's Romulus test facility. To
help with the decision about a test cycle, all ten engines were to be operated
over the Federal Test Procedure (FTP), which is the on-highway transient test,
and an Eight Mode steady state cycle which is similar to the draft ISO 8178
procedure being developed by the manufacturers, through the Society of
Automotive Engineers (SAE) and the International Standards Organization
(ISO).
Two of the manufacturers were unable to supply the on-highway
versions of their engines. In these cases the nonroad engine was modified and
retested with sufficient injection timing retard to meet the 6.9 g/hp-hr
standard.
In addition, a second matching set of engines was provided by one
manufacturer. With the eight engines provided in the first round, the program
consisted of ten engines tested in a total of eighteen engine configurations.
The test results for the eighteen configurations are summarized in the
following reports.
1. "DRAFT: Heavy-duty Engine Testing Report, Nonroad Engine
Configurations, Test Results" -1991 by Mark Doorlag and Mike
Samulski, U.S.EPA.
2. "DRAFT: Heavy-duty Engine Testing Report, Nonroad Engine
Configurations, Injection Timing Effects, Test Results" - 1992 by
Mark Doorlag, U.S.EPA.
3. Dynamometer Testing of Heavy-duty Diesel Engines to Support
Nonroad Regulations" - by Steven G. Fritz, SWRI 08-3426-010,
Sept 1991.
4. Dynamometer Testing of Nonroad Diesel Engines to Support
Nonroad Regulations" - by Michael J. Smith, SWRI 08-4855-150
dated June 1992
5. Detroit Diesel Corporation. Letter to T. Trimble, EPA from John
Fisher, DDI dated September 18,1991.
The following table summarizes the data provided in these eight
reports. Table C-01 provides the composite emission test results of both the
proposed 8-mode test and the on-highway FTP for eighteen engine
-------
DRAFT
159
configurations tested in the test program and the percent difference in the
results. This table is referenced in different parts of this document.
-------
DRAFT
Table C-01
FTP and 8-Mode Emission Test Results
and Comparison of Results
ENGINE
HC
g/hp-hr
(g/kw-hr)
CO
g/hp-hr
(g/kw-hr)
NOx
g/hp-hr
(g/kw-hr)
PM
g/hp-hr
(g/kw-hr)
Smoke
% opacity
Max
Power
hp
(kw)
BSFC
over
cycle
lbs/
bhp-hr
(9/
kw-hr)
ftp
8m od
%di»
ftp
Bmod
%dif
ftp
8mod
%dif
ftp
8mod
%dit
accel
lug
peak
snap
141hp
6-cyl
turbo
John
Deere
A-1
0 73
(0 97)
031
(042)
58
2 57
(3 44)
1 21
(162)
53
609
(816)
610
(818)
0
034
(045)
018
(0 24)
47
154
(115)
0 361
(219)
A-2
086
(115)
043
(0 58)
50
3 61
(4 83)
314
(4 21)
13
1081
(1449)
11 76
(15 76)
-9
040
(053)
042
(0 56)
-5
13
9
22
141
(105)
0348
(212)
A-3
1 58
(211)
093
(124)
41
543
(7 27)
4 77
(639)
12
565
(7 57)
634
(8 49)
-12
099
(133)
109
(146)
-10
20
20
41
134
(100)
0 363
(221)
A-4
084
(1 12)
0 77
(103)
8
426
(5 71)
356
(4 77)
16
604
(809)
710
(9 51)
-18
081
(1 09)
087
(1 16)
-7
23
20
47
137
(102)
0 352
(214)
ave
39
24
-10
6
lOOhp
4-cyl
turbo
Cummins
B-1
0 70
(0 93)
037
(037)
48
1 63
(1 63)
1 13
(1 13)
31
490
(656)
460
(616)
6
046
(061)
042
(0 75)
9
5
11
11
21
106
(79)
0 408
(248)
B-2
1 08
(1 44)
0 75
(100)
30
2 70
(3 61)
220
(295)
19
1214
(16 27)
11 00
(14 74)
9
059
(0 79)
040
(0 53)
33
25
6
54
67
105
(78)
0372
(226)
&-3
1 38
(1 84)
093
(124)
33
2 51
(3 36)
1 54
(206)
39
618
(8 28)
558
(7 47)
10
059
(0 79)
047
(063)
21
100
(75)
0 378
(230)
B-4
4 24
(5 68)
1 50
(201)
65
523
(7 01)
2 51
(3 36)
52
399
(5 34)
3 81
(510)
5
083
(111)
064
(085)
23
89
(66)
0 439
(267)
ave
44
35
7
21
160
-------
DRAFT
Table C-01
(cont.)
ENGINE
HC
g/hp-hr
g/kw-hr)
CO
g/hp-hr
(g/kw-hr)
NOx
g/hp-hr
(g/kw-hr)
PM
g/hp-hr
(g/kw-hr)
Smoke
% opacity
Max
Power
hp
(kw)
BSFC
over
cycle
lbs /
bhp-hr
(91
kw-hr)
ftp
8m od
%dif
ftp
8m od
%dit
ftp
8m od
%dif
ftp
8mod
%dif
accel
lug
peak
snap
285hp
6-cyl
turbo
Cater-
pillar
C-1
0 51
(0 68)
053
(0 71)
-4
210
(2 81)
1 21
(1 62)
42
3 65
(4 89)
344
(4 61)
6
036
(048)
0 21
(0 28)
40
11
4
15
13
270
(201)
0 362
(220)
C-2
1 70
(2 27)
1 14
(1 52)
33
506
(6 78)
1 44
(1 44)
72
6 55
(8 78)
6 49
(8 69)
1
058
(0 77)
018
(0 24)
69
31
3
60
97
288
(215)
0 356
(216)
ave
15
57
3
54
450hp
8-cyl
turbo
Detroit
Diesel
D-1
0 39
(0 52)
032
(0 42)
18
3 85
(519)
0 87
(1 16)
77
6 24
(8 36)
700
(9 38)
-12
039
(0 52)
0 13
(017)
67
41
2
69
69
0372
(226)
D-2
038
(0 50)
036
(0 48)
5
387
(519)
080
(1 07)
79
11 18
(14 87)
1210
(16 21)
-8
026
(0 34)
012
(016)
54
20
2
38
42
450
(336)
0361
(219)
D-3
039
(0 52)
0 32
(042)
18
456
(611)
088
(1 17)
81
5 27
(7 06)
580
(7 77)
-10
054
(0 72)
013
(017)
76
0 379
(230)
ave
14
79
-10
66
130hp
5-cyl
na
Ford
New
Holland
F-1
2 57
(3 44)
095
(1 27)
63
626
(8 39)
6 39
(8 56)
-2
9 65
(12 93)
760
(1018)
21
103
(138)
102
0 36)
1
131
(98)
0 358
(218)
F-2
212
(2 84)
0 70
(0 93)
67
529
(7 09)
558
(7 48)
-5
10 59
(14 19)
9 27
(12 42)
12
090
(1 20)
096
(1 28)
-7
11
26
27
130
(97)
0 337
(205)
F-3
364
(4 87)
1 40
(1 87)
62
590
(7 90)
4 77
(6 39)
19
706
(9 46)
590
(7 90)
16
1 26
(1 68)
1 31
(1 75)
-4
21
34
35
131
(98)
0 314
(191)
ave
64
4
17
-3
161
-------
162
DRAFT
Table C-01
(cont.)
ENGINE
HC
g/hp-hr
g/kw-hr)
CO
g/hp-hr
(g/kw-hr)
NOx
g/hp-hr
(g/kw-hr)
PM
g/hp-hr
(g/kw-hr)
Smoke
% opacity
Max
Power
hp
(kw)
BSFC
over
cycle
lbs /
bhp-hr
(9/
kw-hr)
ftp
8m od
%di1
ftp
8mod
%dif
ftp
8m od
%dif
ftp
8mod
%dif
accel
lug
peak
snap
75hp
4-cy)
na
John
Deere
J-1
1 68
(2 25)
089
(1 19)
47
210
(281)
1 54
(206)
27
707
(947)
608
(815)
14
0 59
(0 79)
038
(0 50)
35
3
4
4
6
76
(57)
0 378
(230)
J-2
140
(188)
064
(0 85)
54
337
(4 52)
350
(4 69)
-4
7 57
(1014)
7 24
(9 70)
4
063
(84)
0 59
(79)
7
12
23
24
17
75
(56)
0 380
(231)
ave
51
12
9
21
Average Average
38
35
3
27
-------
DRAFT
Appendix D: Estimation of the Number of Engine Families
EPA has reviewed information from manufacturers and has estimated
the number of engine families in two ways. One estimate is based on the
current engine family definition in CFR 86.090-24 is as follows.
(a)(1) The vehicles or engines covered by an application for certification
will be divided into groupings of engines which are expected to have
similar emission characteristics throughout their useful life. Each group
of engines with similar emission characteristics shall be defined as a
separate engine family.
(2) To be classed in the same engine family, engines must be
identical in all the following respects:
(i) The cylinder bore center-to-center dimensions.
(ii) [Reserved]
(iii) [Reserved]
(iv) The cylinder block configuration (air cooled or water
cooled; L-6, 90 degree V-8, etc.)
(v) The location of the intake and exhaust valves (or
ports).
(vi) The method of air aspiration.
(vii) The combustion cycle.
(viii) Catalytic converter characteristics.
(ix) Thermal reactor characteristics.
(x) Type of air inlet cooler (e.g., intercoolers and after-
coolers) for diesel heavy-duty engines.
This section also allows the Administrator to further categorize by
criteria in addition to that listed in paragraph (2). However, for this analysis it
is assumed that all engine families are categorized by the criteria in paragraph
163
-------
164 DRAFT
(2) to determine the number of engine families under the current on-highway
definition.
EPA is proposing to allow the manufacturer to categorize nonroad
compression-ignition engine families differently than the current on-highway
engine family definition. EPA is proposing that, if a manufacturer determined
that a series of engine with the same individual cylinder displacement had
sufficiently similar emission characteristics, the manufacturer could forego the
engine family descriptor that uses the number of cylinders and cylinder
arrangement (i.e., In-Line vs. V-shape) as unique engine family identifiers if
the engine does not have aftertreatment. Therefore, to be classified in the
same engine family, engines must be identical in all of the following respects.
1. fuel
2. engine cooling medium (air-cooled, water-cooled)
3. method of air aspiration
4. method of exhaust after-treatment (e.g., catalytic converter,
particulate trap)
5. combustion chamber design
6. bore
7. stroke
8. number of cylinders (engines with aftertreatment devices only)
9. cylinder arrangement (engines with aftertreatment devices only)
EPA's second estimate of the number of nonroad compression-ignition
engine families as categorized by the above criteria is shown in Table D.01.
These engine families have applications above 50 horsepower including
equipment used in construction, industrial, agricultural, mining, forestry,
pumps, compressors, welders, and generators. This does not include engines
used in locomotives, stationary sources, recreational equipment, or marine
applications. The cost analysis for this rulemaking assumes that all engine
families will certify using the new definition.
-------
Table D-01
Estimated Number of Nonroad Engine Families
Manufacturer
Current Definition
New Definition
Caterpillar
21
13
Cummins
56
22
Deere
24
11
Detroit Diesel
48
15
Duetz
34
15
Ford New Holland
28
14
Ford Power Products
9
7
Hatz
5
3
Hercules
10
5
Hino
12
11
Isuzu
10
8
Kubota
3
2
Uster-Petter
8
4
Lombardini
10
4
MAN
1
1
Mitsubishi
5
3
MTU
20
10
MWM
3
2
Navistar
1
1
Perkins
21
16
Peugeot
13
7
Scania
10
10
Teledyne
4
2
Toyota
5
3
VM
26
10
Volkswagen
5
3
Volvo-Penta
11
8
Yanmar
3
3
TOTAL
406
213
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DRAFT
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DRAFT
Appendix E: Hourly Test Length Estimate
The test procedure proposed in this rulemaking is based on the ISO-
8178 8-mode procedure. However, the proposed test procedure is modified.
EPA modifications to ISO 8178 include tightening of testing and measuring
equipment specifications and calibration requirements, changes to the order of
the test modes, and the inclusion of raw exhaust and full dilution exhaust
sampling options. The modifications to ISO 8178 are intended to ensure
greater uniformity in practices and results among manufacturers for gaseous
emission measurement. This is an explanation of the time estimate derived for
the proposed modified test procedure.
There are two test time estimate categories. One is the "set up" time
and the other is the "test" run time.
The set up time will depend on whether the test has previously been
run on a particular engine block. If the test has been run on the particular
engine block, then less time will be required to set up the test than if no test
had been run.
If the test has been run before on the engine block in question, then the
following 3 steps must be done.
1. make engine adapters for the dyno
167
-------
168 DRAFT
2. make flywheel adapters for the dyno
3. make both inlet and exhaust system hook ups to your
measurement system (This involves setting the measurement
system up with the correct back pressure and inlet depression.)
These are time consuming tasks. This estimate represents the minimum
time required. It is assumed that these three steps are performed once per
engine family. However, it is likely to be several times per engine family
because the boring holes for screws may be different for each flywheel.
Further, the range of cylinders in the engine family may necessitate different
inlet and exhaust pipes. There may be other changes between models in the
same engine family as well. Ignoring these differences, the "first time set up"
estimate is four 8-hour days (i.e., 32 hours).
If an emission test has been run on the engine block in question, then
the first time set up work is complete. The necessary equipment can be
retrieved and re-assembled for another test. The set up in this case is termed
the "yearly set up" because it would be the set up done to perform a
certification test after the first model year in which an engine family is
certified. The yearly set up includes connecting the
• throttle linkage,
• wiring,
• pressure transducers, and
• fuel line hookup.
EPA estimates 8 hours to do the yearly set up. In addition, a selective
enforcement audit test would require this yearly set up.
Therefore, the estimated total set up time required for the first time the
test is performed is 32 hours plus 8 hours (i.e., 40 hours). Each yearly test
would only require 8 hours for set up.
"Running the test" and gathering emissions involves the following five
steps.
1. Setting the inlet and exhaust restrictions. Minimal time is
required for this.
-------
DRAFT
169
2. Testing performed to stabilize the test conditions. Full emissions
are not taken. This takes about 4 hours.
3. Testing done with full emissions measurement. This takes 3
hours.
4. Documentation of the test. This takes about 2 hours.
5. Taking the engine out of the test cell. This takes about 2 hours.
Therefore, it is estimated that about 11 hours are required to run the test.
The Table E-01 summarizes the hourly test estimates.
Table E-01
Hourly Test Estimates
category
first test performed
yearly tests
or SEA tests
first tme set up
32
0
yearly set up
8
8
running the test
11
11
TOTAL
51
19
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