&EPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-B-16-023
March 2016
Nonroad Large Spark-Ignition Engines: Exhaust and Evaporative Emission Standards
Federal b
Tier
1 °
29
Year
2004-
2006
2007+
General Duty-Cycle
Standards
HC+NOxa
(g/kW-hr)
4.0 d
2.79
CO
(g/kW-hr)
50.0
4.49
Alternative Standards
for Severe-Duty
Engines
HC+NOxa
(g/kW-hr)
4.0 d
2.7
CO
(g/kW-hr)
130.0
130.0
Field Testing
Standards
HC+NOx a
(g/kW-hr)
-
3.89
CO
(g/kW-hr)
-
6.59
Useful Life
(years /
hours)
7 / 5,000 e
7 / 5,000 e
Evaporative Emission Standards (for engines fueled by a volatile liqued fuel)
Fuel line
permeation
Diurnal
emissions
Running
Loss
Nonmetallic fuel lines must meet the permeation
tions of SAE J2260 (November 1996)
specifica-
Evaporative HC emissions may not exceed 0.2 grams
per gallon of fuel tank capacity
Liquid fuel in the fuel tank may not reach boiling during
continuous engine operation in the final installation at an
ambient temperature of 30°C
51-
Warranty
Period
3 / 2,500 f
3 / 2,500 f
Notes:
The numerical emission standards for hydrocarbons (HC)
must be met based on the following types of hydrocarbon
emissions for engines powered by the following fuels: (1)
non-methane hydrocarbons (NMHC) for natural gas; (2)
total hydrocarbon equivalent (THCE) for alcohol; and (3)
total hydrocarbons (THC) for other fuels.
Voluntary Blue Sky standards for large spark-ignition (SI)
engines are available. Engines with displacement at or
below 1,000 cubic centimeters (cc) and maximum power
at or below 30 kilowatts (kW) may be certified under the
program for small SI engines.
Emission standards are based on testing over a steady-
state duty-cycle.
The Tier 1 HC plus nitrogen oxides (NOx) emission stan-
dard for in-use testing is 5.4 grams per kW-hour (g/kW-hr).
Useful life is expressed in years and hours, whichever
comes first. These are the minimum useful life
requirements. For severe-duty engines, the minimum use-
ful life is seven years or 1,500 hours of operation, which-
ever comes first. A longer useful life in hours is required
if: (a) the engine is designed to operate longer than the
minimum useful life based on the recommended rebuild in-
terval; or (b) the basic mechanical warranty is longer than
the minimum useful life.
f A longer warranty period of five years or 3,500 hours ap-
plies for high-cost warranted parts (i.e., components with a
replacement cost at time of certification exceeding $400 [in
1998 dollars]).
g Optional engine certification is allowed according to the
following formula: (HC+NOx) x COO.784 < 8.57. The
HC+NOx and carbon monoxide (CO) emission levels se-
lected to satisfy this formula, rounded to the nearest 0.1 g/
kW-hr, become the emission standards that apply for those
engines. One may not select an HC+NOx emission stan-
dard higher than 2.7 g/kW-hr or a CO emission standard
higher than 20.6 g/kW-hr.
Code of Federal Regulations (CFR) Citations:
40 CFR 1048.101 = Exhaust emission standards
40 CFR 1048.105 = Evaporative emission standards
40 CFR 1048.110 = Engine diagnostic requirements
40 CFR 1048.120 = Warranty requirements
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