73-24 AEB
Exhaust Emissions from a 25-Passenger
Organic Rankine Cycle Bus
June 1973
Emission Control Technology Division
Office of Air and Water Programs
Environmental Protection Agency
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Background
An Organic Rankine Cycle (ORC) power system designed and built
by Sundstrand Aviation was installed in a small (25-passenger)
transit bus, in a program to demonstrate the feasibility of such
power systems in small buses. The work was done under a grant
from the U.S. Department of Transportation to Dallas (Texas)
Transit Systems. The installation was accomplished by LTV
Aerospace Group, who were also the overall program managers.
After the installation of the ORC power system and an extensive
period of shakedown, development and optimization, arrangements
were made with Sundstrand for exhaust emissions tests at the
Office of Mobile Source Air Pollution Control (OMSAPC), Ann Arbor
laboratory. The tests of the ORC bus reported herein were con-
ducted over a five-week period in March and April 1973.
The emissions tests were conducted by the Test and Evaluation
Branch of the Emission Control Technology Division as part of
a continuing effort to stay abreast of alternative power systems
development and assess the emission control potential of such
systems. Transportation of the bus from Sundstrand Aviation,
Rockford, Illinois, to the Ann Arbor laboratory was provided by
LTV. Sundstrand provided personnel to operate the bus and
interpret engine parameter data.
Vehicle Description
The bus chosen for this project was a Twin Coach model TC-25
built by Highway Products, Inc. of Kent, Ohio. The engine usually
installed in this 25-passenger bus is a 413 cubic inch displace-
ment (CID) Chrysler gasoline-fueled V-8 internal combustion
engine.
The Sundstrand-designed Organic Rankine Cycle power system
installed in the bus is described in Reference 1 at the end
of this report. Briefly, the power system includes a monotube
heater that provides supercritical working fluid (CP-25, toluene)
for a turbine expander. Turbine power output goes through a
-reducing gear box to the three-speed automatic transmission
originally installed in the bus. Liquid propane is the fuel.
The engine was installed in the rear of the bus in the normal
engine compartment, with the condenser mounted on the roof of
the bus at the rear.
The curb weight of the "stock" bus is about 10,500 pounds. The
bus as tested with the ORC power system installed weighed about
14,000 pounds (2,500 Ibs. front, 11,500 Ibs. rear) due to instru-
mentation and an increased engine weight. All testing was done
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-2-
with an inertia weight of 12,800 pounds to simulate the weight
of the standard TC-25 bus with 20 passengers.
Test Program
The ORC bus arrived at the Ann Arbor laboratory on Friday,
March 16, 1973. Vehicle preparation and checkout took several
days. Testing started on March 22 and continued through April
13. However, due to several equipment and vehicle problems,
only a small number of tests were completed. These were
principally a modified version of the 13-mode heavy duty diesel
engine Federal test procedure. This modified procedure is
similar to the heavy duty diesel engine test procedure developed
by the California Air Resources Board and the Engine Manu-
facturers Association. This procedure, which will be referred
to as the Federal 13-mode procedure, is described in SAE paper
number 700671, and the Federal Register of November 15, 1972,
Volume 37, Number 221, Part II.
For these tests a heavy duty electric chassis dynamometer was
used which had motoring capability and permitted both speed and
torque control. The dynamometer is equipped with large dia-
meter (40") rolls to minimize slippage and tire loss problems.
Rear wheel horsepower was measured and engine brake horsepower
was then calculated to provide the basis for determining brake
specific emissions.
The heavy duty diesel procedure is a steady state procedure for
testing a diesel
load as the oper
"rated":and "into
engine on an engine dynamometer with engine
iting variable at each of two engine speeds,
fermediate". The load is varied from zero to
maximum torque available at each of these two engine speeds,
in steps of 25% of maximum torque. Three idle periods are
interspersed among these load points, for a total of 13 oper-
ating modes. Rated speed is self-explanatory; the maximum
allowable engine speed. Intermediate speed is defined in the
procedure as "...peak torque speed or 60% of rated speed,
whichever is higher." For the ORC power system, 32,000 and
20,000 rpm were selected as the rated and intermediate speeds,
respectively, since these would give approximately the same
transmission speeds as the internal combustion engine. The
true rated speed of the ORC turbine expander is 35,000 rpm.
The 13-mode procedure calls for continuous analysis of exhaust
pollutant concentrations and measurement of engine fuel and air
consumption rates for calculation of exhaust pollutant mass
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-3-
emissions. However, for simplicity and ease of calculation in
our tests of the ORC bus, the Constant Volume Sampling technique
(CVS) was employed. In the CVS method a positive displacement
air pump pulls a constant volume stream consisting of all the
engine exhaust plus dilution air. From this mixture a small
sample is pumped into an impermeable Tedlar plastic bag for
analysis at the end of the test period. The product of
pollutant mole concentration times pollutant density times
constant volume flow rate, in appropriate units, gives pollutant
mass emissions.
The sample bags were analyzed using the usual array of instru-
ments: unburned hydrocarbons (HC) were measured with a flame
ionization detector (FID), CO and C02 with non-dispersive in-
frared (NDIR) analyzers, and nitrogen oxides (NOx) with a
chemiluminescence (CL) device. An attempt was made to run at
steady speeds of 0, 15, 30, 45, and 60 mph with road load power
settings. Only a few of these were successful because of power
system problems.
Early in our testing of the ORC bus it became evident that it
would be extremely difficult to obtain stable preselected horse-
power settings due to the nature of the engine design and controls,
To provide good off-design performance, the turbine is operated
at a constant pressure ratio by varying the number of nozzles
supplying the superheated working fluid to the turbine. Thus,
changing the throttle position increases the power in steps.
The test procedure, therefore, was modified to set the power
by selecting rpm and the number of nozzles. Idle required 1
to 2 nozzles and was automatically cycled by the control logic.
Minor mechanical problems were encountered which interrupted
testing and'limited the total number of useful tests. The ORC
power system became restricted to operation on 1,2,4 or 5
nozzles, therefore, several tests were run at only three
power settings.
Desired load and engine speed settings were calculated prior to
each test. However, when these values were adjusted for dyna-
mometer friction losses, rear-wheel motoring losses, and trans-
mission efficiency, the observed horsepower differed considerably
from the 25, 50 and 75% hp values. Initially, it had been intended
to report emissions in terms of net horsepower measured at the'
rear wheels as was done on the bus testing reported in Reference
2. However, the observed horsepower was highly variable from
test to test unless corrected for dynamometer friction and rear
wheel motoring lessee. Therefore, the horsepower valuer urcc!
in calculating the ORC bus brake specific emissions and
'tabulated in the tables are those based on the turbine
performance. These problems were not encountered during
the later tests of the gasoline bus.
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-4-
Experimental data on tire losses and automatic transmission
efficiencies, obtained from industry sources, were used to
back-calculate brake horsepower output.
Tests of a "Baseline" Bus
The Test and Evaluation Branch previously tested the ORC bus
in its stock, as-received-from-the-factory, condition with
the conventional engine installed, in order to establish base-
line emissions with which the ORC power system emissions could
be compared. However, these test results, reported in Reference
2, were not directly comparable due to the inertia weight and
power absorption limitations inherent in the Clayton dynamometer
used for those tests. Therefore, the tests of a gasoline-powered
bus were repeated on the heavy duty large roll chassis dynamometer
that was used for the ORC bus tests.';
The second baseline bus was a Twin Coach 29-passenger city bus
powered by a 413 CID Chrysler V-8 engine using gasoline. This
vehicle is identical to the TC-25 except that it is three feet
longer and weighs 12,000 pounds. The bus was manufactured in 1970
and the only emission control was positive crankcase ventilation.
This vehicle was obtained through the courtesy of the City of
Muskegon, Michigan, where it had seen extensive use in city bus
service.
The gasoline bus was driven from Muskegon to the Ann Arbor
facility on Tuesday, April 17, 1973. Since the vehicle had been
in storage for many months and had about sixty thousand miles
of city bus service it was hard to start and ran poorly. The
engine was given a major tune-up at the Ann Arbor lab prior
to testing.
The inertia weight set into the dynamometer was the same as
that for the ORC bus, 12,800 pounds. Weights were placed in the
gasoline bus to obtain the same rear wheel, rear axle, and
dynamometer axle loads as the ORC bus. All emissions tests
used the Constant Volume Sampling method.
Operating conditions included a simulation of the Federal
13-mode procedure, steady state tests (constant speed at road
load), the LA-4 light duty vehicle urban driving cycle (as
used in Federal emissions certification tests), and the Ann
Arbor-1 (AA-1) Urban Bus Cycle.
The AA-1 cycle is a speed versus time trace generated in the
summer of 1971 by attaching a fifth wheel to one of the buses
of the Ann Arbor Transportation Authority. The cycle is not
an official test cycle, but rather is used as an experimental
tool for comparing buses. The cycle consists of 26 start/stop
modes, and the 5.4-mile route requires 29.5 minutes to complete,
for an average speed of about 11 mph. The maximum speed on the
cycle is 38 mph.
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-5-
The procedure for the 13-mode tests was to establish the
desired engine speed by using the dynamometer to control
vehicle speed. At this speed the load is controlled by the
vehicle throttle setting. Bag samples of the diluted exhaust
gas were taken at 2%, 25%, 50%, 75% and 100% of the maximum
power at the chosen engine speed. The idle modes were run with
the transmission in neutral. It had previously been determined
that 2,000 rpm and 3,200 rpm were the desired intermediate
and rated speeds for the Chrysler 413 engine in the bus, as
reported in Reference 2. However, dynamometer speed limitations
prevented running the gasoline engine bus above 2,900 rpm at
the lower power settings; therefore, 2,900 rpm was used as the
rated engine speed for this vehicle. To develop a valid dyna-
mometer road load for the AA-1 bus route, LA-4 urban driving
cycle, and the steady state tests, the gasoline bus was taken
to a test track to obtain steady state road load data: engine
speed, manifold vacuum, vehicle speed. These conditions were
duplicated on the chassis dynamometer and a read load curve,
Table 13, was developed. The steady state test modes on the
chassis dynamometer were idle, 10, 20, 30, 40, 50, and 60 mph
cruises, each maintained for five minutes to allow time for
an adequate sample to be collected.
In addition to the emissions test a simple exterior noise test
was conducted using the SAE Recommended Practice J366, for full
throttle acceleration only. Four runs on an open track were
made in one direction only, because of nearby equipment
operating. The closed throttle deceleration test was not run.
Maximum engine speed attained was 2,900 rpm since the automatic
transmission upshifted at that speed instead of the governed
speed of 3,600 rpm.
Results and Discussion
Results of the emissions tests on the ORC bus are presented in
the Appendix in Tables 1 through 4, and on the "baseline"
gasoline-engined bus in Tables 5 through 12. Emissions of C02
are included to indicate fuel consumption. The fuel economy
figures in the tables were calculated by a carbon balance
equation from the mass emissions of HC, CO, and C02. Rolling
resistance data on the gasoline bus are presented in Table 13.
Table 14 shows the results of the noise tests on the gasoline
bus. Figure I shows the data used to calculate brake specific
emissions for the ORC bus.
Mass emissions from the 13-mode tests on the ORC bus are pre-
sented as grams per Bhp-hr, grams per minute, and grams per mile
in Tables 1, 2 and 3 respectively. The variability of all emissions
was greater than normally experienced. This was due to the
difficulty in duplicating test conditions and adjustments to
the ORC bus fuel-air mixture. The only test completed at the
optimum air-fuel ratio was the test on April 12.
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Using the brake specific emissions from Figure I (next page)
and Table 5 to compare the two vehicles, the following table
of average brake specific emissions can be calculated:
Grams Per Brake Horsepower-Hour
ORC Bus (4-12)
Gasoline Bus
'77 Cal. Std.
HC
2.1
8.1
CO
20.0
53.4
25
NOx
2.0
12.4
HC+NOx
Thus, the ORC bus achieved improvements of 74%, 63% and 85%
for HC, CO and NOx emissions. This is a considerable improvement
over a vehicle whose engine easily met the current (1973)
standards. In addition, the ORC bus meets the 1977 California
HC, CO and NOx standards. Several important cautions must be
observed however; 1) the ORC bus is a feasibility model and,
although considerable improvements could probably be made,
the usage deterioration to be expected cannot be predicted;
2) this comparison was made with a well used, high mileage
vehicle which did not have current state-of-the-art emission
improvements.
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-7-
From two sets of selected data points composite brake
specific emissions were calculated. These are listed at
the bottom of Table 1. Since a full set of data was not
available, these are only an approximation and should
not be given too much weight in comparisons with full
13-mode tests of other power systems.
Emissions from the steady state cruise modes are listed in
Table 4 as grams per minute and grams per mile. No horsepower
readings were obtained due to equipment problems.
Mass emissions from 13-mode tests on the gasoline bus are
listed in Tables 5,6, and 7 as grams per Bhp-hr, grams per
minute, and grams per mile, respectively. The brake specific
emissions at the bottom of Table 5 were calculated from
those data points and represent composite emissions as
calculated by the Federal 13-mode procedure. The brake
horsepower values used in these calculations are the sum
of measured dynamometer horsepower plus estimates of tire
losses and transmission losses.
From experimental tire data supplied by Mr.Kenneth Campbell
of Firestone Tire & Rubber Co., the rear wheel horsepower
losses due to the tires would be 10.5 hp at 30 mph and 17 hp
at 50 mph. This agreed with measured tire power losses at
those speeds. Data supplied by Mr. Arnold Brookes of Chrysler
Corporation were used to calculate overall transmission
efficiencies.
In Table 8, HC and CO concentration data are presented. The
gasoline bus data were calculated using those data points
in the 13-mode test for which the manifold vacuum was
approximately the same as required by the Federal heavy duty
gasoline engine test procedure. The results are thus only an
approximation and should be used cautiously.
Mass emissions, in grams per Bhp-hr, are presented in Table 9.
Composite 13-mode results from the gasoline bus are presented,
as well as results from an approximation of the Federal heavy
duty gasoline engine procedure.
Table 10 presents the results from a single 1975 FTP on the
gasoline bus. The test was run on the heavy duty chassis
dynamometer with a road load power vs. speed curve and an
inertia weight of 12,800 pounds.
The Ann Arbor-1 bus route was run on the dynamometer on three
different days. Composite mass emissions are listed in Table 11,
In these tests the startup and first 390 seconds of the driving
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Figure 1
25-Passenger Organic Rankine Cycle Bus Mass Emissions
Abbreviated Federal 13-Mode Procedure
Grams Per Minute
Test Date
4-4*
4-12
Nozzles Open Horsepower Turbine Speed HC
1-2 0 Idle .78
1 9.0 22000 rpm .89
2 27.9 20000 rpm .03
4 59.7 20000 rpm .34
5 85.8 20000 rpm .28
1 10.9 32000 rpm 1.16
2 36.9 32000 rpm .58
4 79.6 32000 rpm .49
CO
Brake Specific Emissions =
0
9.0
27.9
59.7
85.8
10.9
36.9
79.6
0
0
9.9
27.9
58.4
11.6
36.1
78.1
0
(pollutant
Idle
22000
20000
20000
20000
32000
32000
32000
Idle
Idle
20000
20000
20000
30000
32000
32000
Idle
x WF) 60
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
rpm
P
1-2 0 Idle 3.66
1-2 0 Idle 1.52
1 9.9 20000 rpm 1.78
2 27.9 20000 rpm .57
4 58.4 20000 rpm .10
1 11.6 30000 rpm 1.48
2 36.1 32000 rpm .41
4 78.1 32000 rpm .05
1-2 0 Idle 1.85
7.77
6.48
3.29
341
330
600
42.43 1287
37.61 1102
16.46 480
33.74 1034
36.20 1244
18.22
10.16
7.22
13.70
631
498
432
777
12.46 1346
6.44 370
7.19 721
8.97 1256
7.36 422
NOx
.30
.29
.95
3.57
3.18
.41
1.28
1.86
.46
.46
.38
.95
:.04
.34
.94
..99
.38
(measured Bhp x WF)
Pollutant (HC, CO, NOx) mass in grams/minute
WF = .2 x avg. idle for idle modes
_._§_
WF = n n = number of power modes
n = 7 for 4-4, n = 6 for 4-12
4-4 Brake Specific Emissions - grams/Bhp-hr
4-12 Brake Specific Emissions - grams/Bhp-hr
.99
2.14
36.8
19.96
2.34
1.97
*Date for 4-4 is not at optimum fuel-air ratio.
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-8-
cycle are collected in one sample bag and the remaining 23
minutes of the cycle in the next two bags. In the interests
of time the Hot Start tests of 5-4 and 5-8-73 were not complete
29.5 minute tests. Instead, only the startup and the first
390 seconds were run, after the complete Cold Start test had
been run. The Hot Start bag data were combined with the data
from the last 23 minutes of the Cold Start test to give the
composite mass emissions listed in Table 11, under the
assumption that the engine is operating the same at 390 seconds
regardless of the type of start.
Data from the steady state tests are presented in Table 12.
Fuel economy was calculated by the carbon balance method.
For the LA-4 and Ann Arbor-1 tests on the gasoline bus, a road
load curve was determined using the data from column 1 in
Table 13. The values in column 1 are the dynamometer horsepower
readings that resulted from matching engine speed and manifold
vacuum with those recorded at the test track. In column 2
are typical readings from a subsequent test on the dynamometer.
The differences at each speed were a result of dynamometer
non-repeatability, because engine speed and manifold vacuum
were always matched with the road test values. Columns 3 and
4 apply to the 25-passenger bus in which the ORC power system
was installed. The bus manufacturer's predicted road loads
(for a gasoline ICE-powered bus) are listed in column 3.
Sundstrand measured the values in column 4 during coastdown
tests on the road with the ORC bus. The differences between
columns 3 and 4 are probably due to the increased weight of the
ORC bus and the increased drag due to the roof-mounted vapor
condenser.
The noise data in Table 14 are from four runs, all in one
direction, all on the same side of the bus. The A Scale
was used; results are in decibels.
Conclusions
These tests of an ORC and a gasoline ICE bus have shown that
chassis dynamometer testing for emissions from large vehicles
at high loads is possible. For the gasoline bus it was possible
to compare results with engine certification data. For those
tests in which the two vehicles can be directly compared, the
ORC bus showed considerable emissions improvement over the
gasoline bus. Additional work will be necessary to reduce
test variability so that conditions can be duplicated.
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-9-
REFERENCES
(1) M. Reck and D. Randolf, "An Organic Rankine Cycle
Engine for a 25-Passenger Bus", SAE International
Automotive Engineering Congress, January 1973,
No. 730212. |
(2) "Exhaust Emissions from a 25-Passenger Internal
Combustion Engine-Powered Gasoline-Fueled Bus",
72-7, MSAPC, Environmental Protection Agency.
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APPENDIX
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Table 1
25-Passenger Organic Rankine Cycle Bus Mass Emissions
Federal Experimental 13-Mode Procedure
Grams Per Brake Horsepower-Hour
1 nozzle
1 nozzle
2 nozzles
2 nozzles
2 nozzles
4 nozzles
4 nozzles
5 nozzles
1 nozzle
1 nozzle
2 nozzles
2 nozzles
4 nozzles
4 nozzles
4 nozzles
9.0 hp 22000 rpm
9.9 hp 20000 rpm
31.3 23000 rpm
27.9 20000 rpm
27.9 20000 rpm
59.7 20000 rpm
58.4 20000 rpm
85.8 20000 rpm
10.9 32000 rpm
11.6 30000 rpm
36.9 32000 rpm
36.1 32000 rpm
74.6 27500 rpm
79.6 32000 rpm
78.1 32000 rpm
Date
4-4*
4-12
4-4
4-4
4-12
4-4
4-12
4-4
4-4
4-12
4^4
4-12
4-4
4-4
4-12
HC
5.96
10.8
1.00
.07
1.23
.33
.11
.20
6.35
7.66
.94
.68
.26
.37
.04
CO
43.3
43.7
44.3
7.09
29.44
42.67
12.81
26.28
90.2
33.30
54.8
11.97
33.44
27.28
6.90
CO?.
2200
2618
1113
1291
1671
1294
1384
770
26.28
1865
1681
1201
900
937
965
NOx
1.95
2.30
1.20
2.05
2.04
3.59
2.10
2.23
2.24
1.76
2.08
1.57
1.41
1.40
1.53
Fuel Consumption
Ib/Bhp-hr
1.68
2.00
.87
.96
1.27
1.0
1.03
.60
2.05
1.43
1.30
.90
.70
.72
.72
*Data\for 4-4 is not at optimum fuel-air ratio.
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1-2 nozzles
1-2 nozzles
1-2 nozzles
1-2 nozzles
1-2 nozzles
1 nozzle
1 nozzle
1 nozzle
Mode
Table 2
25-Passenger Organic Rankine Cycle Bus Mass Emissions.
Federal 13-Mode Procedure
Date
HC
Start 5
Warm-up
Start
Start
Warm-up
Idle*
Idle
Idle*
Idle*
Idle
Idle
9.0*hp
9.9*
!l-3 hp
7 .9 * hp
4-4*
4-6*
4-13
4-6
4-4
4-6
4-12
4-12
4-13
4-4
4-4
4-12
4-4
4-12
3.38
4.67
2.96
2.51
.78
1.08
3.66
1.52
1.46
.59
.89
1.78
.52
.57
Grains Per Minute
CO C00 NOx
20.53
23.64
16.00
39.83
7.77
24.10
18.22
10.16
8.82
6.17
6.48
7.22
23.18
13.70
" *•
706
627
606
542
341
482
631
498
518
613
330
432
582
111
.648
.42
.48
.39
.30
.41
.46
.46
.46
.65
.29
.38
.63
.948
23500 rpm
22000 rpm
20000 rpm
23QOO rpm
20000 rpm
nozzles 27. *hp 4-4
.03
3.29 600. .95
20000 rpm
*Datafor 3-30, 4-4, and 4-6 is not at optimum fuel-air ratio.
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Table 2 cont.
4
4
4
5
nozzles
nozzles
nozzles
nozzles
Mode
59.7*hp
58.4* hp
74.6 hp
85.8*hp
Date
4-4
4-13
4-4
4-4
HC
.34
.10
.33
.28
Idle $
Warm-up
1
1
2
2
4
4
nozzle
nozzle
nozzles
nozzles
nozzles
nozzles
10.
11.
36.
36.
79-
78-
9*hp
6*
9*hp
l*hp
6*hp
l*hp
4
4
4
4
4
4
4
-4
-4
-12
-4
-12
-4
-12
1.03
1.16
1.48
.58
.41
.49
.05
5 nozzles
Idle
1-2 nozzles
4-4
4-12
.38
1.85
CO C02 NOx
42.43 1287 3.57
12.46 1346 2.04
41.62 1120 1.76
37.61 1102 3.18
17.86 676 .50
16.46 480 .41
6.44 370 .34
33.74 1034 1.28
7.19 721 .94
36.20 1244 1.86
8.97 1256 1.99
43.74 1206 1.92
20000 rpm
20000 rpm
27500 rpm
20000 rpm
32000 rpm
33000 rpm
32000 rpm
32000 rpm
32000 rpm
32000 rpm
32000 rpm
7.36 422
.38
*Values used to calculate mass emissions in grams/Bhp-hr
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Table 2 cont.
Mode
Idle
85.9
21
55
79.5
hp
hp
hp
hp
Date
3-
3-
3-
3-
3-
30
30
30
30
30
HC
1.86
.22
.13
.35
.16
CO C0_2
7.
28.
20.
31.
30.
35
04
46
83
78
417
1208
714
1333
1371
jSTOx
.34
1.89
.82
2.04
2.26
21000
20000
16000
18000
32000
rpm
rpm
rpm
rpm
rpm
Nozzles Open
1
•5
2
.4
4
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Table 3
25-Passenger Organic Rankine Cycle Bus Mass Emissions
Federal 13-Mode Procedure
Grams Per Mile
1 nozzle
1 nozzle
2 nozzles
2 nozzles
2 nozzles
4 nozzles
4 nozzles
4 nozzles
5 nozzles
1 nozzle
1 nozzle
2 nozzles
2 nozzles
4 nozzles
4 nozzles
5 nozzles
2 nozzles
4 nozzles
4 nozzles
9.0 hp
9.9 hp
31.3 hp
27.9 hp
27.9 hp
59.7 hp
58.4 hp
14.6 hp
85.4 hp
10.9 hp
11.6 hp
36.9 hp
36.1 hp
79.6 hp
78.1 hp
85.9 hp
21.0 hp
55 hp
79.5 hp
Mode
22000 rpm
20000 rpm
22000 rpm
20000 rpm
20000 rpm
20000 rpm
20000 rpm
27500 rpm
20000 rpm
32000 rpm
30000 rpm
32000 rpm
32000 rpm
32000 rpm
32000 rpm
20000 rpm
17500 rpm
20000 rpm
32000 rpm
Date
HC
CO
4-4*
4-12
4-4
4-12
4-4-.
4-4
4-12
.4-4
4-4
4-4
4-12
4-4
4-12
4-4
4-12
3-30
3-30
3-30
3-30
1.78
4.25
1.98
2.50
.14
1.46
.46
1.01
1.19
1.84
2.31
.96
1.09
.79
.14
1.12
3.68
1.49
.43
12.9
17.2
87.8
59.8
13.4
18.2
55.6
128.6
162.3
26.2
10.1
56.1
19.1
58.6
24.5
140.4
88.0
136.3
84.1
co2
658
1033
2205
3393
2433
5558
6007
3459
4757
762
579
1719
1919
2015
3430
NOx
.58
.92
2.38
4.15
3.87
15.42
9.12
5.43
13.75
.65
.53
2.13
2.51
3.01
5.44
6047
3071
5706
3745
9.44
3.52
8.73
6.18
*Data for 3-30, and 4-4 is not at optimum fuel-air ratio.
-------
Table 4
25-Passenger Organic Rankine Cycle Bus Mass Emissions
Steady State Modes
Grams Per Minute
Mode
Idle
0 mph
15 mph
24 mph
27 mph
Mode
Idle
0 mph
15 mph
24 mph
27 mph
Date
3-26*
3-26
3-26
3-23*
3-26
Date
3-26
3-26
3-26
3-23
3-26
HC
1.26
2.27
1.95
.93
1.54
HC
N/A
N/A
8.30
2.46
8.95
CO
11.26
114.93
95.86
103.35
117.83
Grams Per Mile
CO
N/A
N/A
407.92
272.81
684.30
co2
465.7
1082.8
901.6
1430.4
1363.8
co2
N/A
N/A
3836.2
3775.6
7923.3
NOx
.48
1.14
.89
1.67
1.62
NOx
N/A
N/A
3.81
4.40
9.38
*Data for 3-23 and 3-26 is not at optimum fuel-air ratio.
-------
HP
RPM
Date
Table 5
29^Passenger Gasoline-Powered Bus Mass Emissions
Federal 13-Mode Procedure
Grams Per Brake Horsepower Hour
HC
CO
CO,
NOx
Fuel Consumption
Ib/Bhp-hr
5.6
2.4
21.2
32.2
77.0
64.8
100.9
92.6
107.4
107.1
3.4
5.9
27.2
37.2
62.7
67.4
91.1
97.9
130.1
127.0
2000
2010
2000
2000
2000
2000
2000
2000
2000
2000
2900
2900
2900
2900
2900
2900
2900
2900
2900
2900
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-8
5-16
5-8
5-16
5-8
5-16
5-8
5-16
5-8
5-16
44.58
164.63
4.40
2.71
1.93
1.86
1.04
1.33
.48
.68
475.69
347.71
59.39
42.87
3.38
1.89
1.18
1.23
.41
1.82
240.08..
685.30
21.94
27.72
21.77
30.35
11.76
15.25
17.67
20.99
179.31
197.07
52.29
75.65
44.74
39.68
22.08
35.02
22.26
116.52
2779
5373
966
807
564
556
450
544
462
507
3353
3378
802
809
650
617
576
633
510
470
13.57
18.97
11.23
18.74
8.56
15.03
7.36
14.27
5.42
14.10
29.81
40.75
13.17
15.34
16.77
14.97
16.78
13.97
13.16
6.88
1.98
4.17
.61
.52
.36
.36
.28
.35
.30
.33
3.09
2.88
.64
.64
.44
.41
.37
.38
.33
.39
-------
Table 6
29-Passenger Gasoline-Powered Bus Mass Emissions
-federal 13-Mode Procedure
Grains Per Minute
HP
Idle
Idle
5.6
2.4
21.2
32.2
77.0
64.8
100.9
92.6
107.4
107.1
Idle
Idle
Idle
3.4
5.9
27.2
37.2
62.7
67.4
RPM
1075
1075
2000
2010
2000
2000
2000
2000
2000
2000
2000
2000
1050
1075
1050
2900
2900
2900
2900
2900
2900
Date
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-8
5-16
5-7
5-16
5-8
5-16
5-8
5-16
HC
3.26
3.16
4.14
6.46
1.56
1.45
2.48
2.01
1.75
2.05
.85
1.21
4.19
3.06
3.54
27.38
34.02
26.92
26.61
3.52
2.13
CO
63.87
59.96
22.31
26.90
7.76
14.90
27.95
32.76
19.78
23.55
31.64
37.47
69.82
53.93
58.93
10.32
19.28
23.7
46.95
46.72
44.59
co2
77
73
358
211
342
433
724
601
774
840
838
905
72
75
74
193
331
363
502
679
693
NOx
.02
0
1.26
.74
3.97
10.07
10.99
16.22
12.38
22.04
9.72
25.17
.03
.04
0
1.18
3.99
5.97
9.52
17.52
16.81
-------
Table 6 cont.
HP
91.1
97.9
130.1
127.0
Idle
Idle
RPM
2900
2900
2900
2900
1025
1025
Date
5-8
5-16
5-8
5-16
5-8
5-16
HC
1.80
2.00
.87
3.86
3.62
3.71
CO
33.53
57.13
48.28
246.6
52.15
57.98
C02
875
1033
1106
996
61
67
NOx
25.49
22.79
28.54
14.56
.08
0
Brake Specific Emissions
GMS/Bhphr (5-7/5-8)
GMS/Bhphr (5-16)
Brake Specific Emissions =
7.66
40.23
8.62 66.48
(Pollutant x WF) 60
(measured Bhp x WF)
11.22
13.52
Pollutant (HC, CO, NOx) mass in grams per minute.
WF = .2 for idle (use average of three idles)
WF = .08 for all others
-------
Table .7
29-Passenger Gasoline-Powered Bus Mass Emissions
Federal 13-Mode Procedure
Grams Per Mile
HP
RPM
Date
HC
CO
CO.
NOx
5.6
2.4
21.2
32.2
77.0
64.8
100.9
92.6
107.4
107.1
3.4
5.9
27.2
37.2
62.7
67.4
91.1
97.9
130.1
127.0
2000
2010
2000
2000
2000
2000
2000
2000
2000
2000
2900
2900
2900
2900
2900
2900
2900
2900
2900
2900
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-7
5-16
5-8
5-16
5-8
5-16
5-8
5-16
5-8
5-16
5-8
5-16
6.48
10.18
2.46
2.38
4.30
3.60
3.17
3.91
1.92
2.82
28.79
37.44
29.55
29.88
3.99
3.15
2.04
2.95
.98
5.71
34.89
42.36
12.25
24,37
48.38
58.79
35.98
44.84
71.61
87.24
10.85
21.22
26.01
52.72
52.80
65.83
38.15
84.35
54.18
365.4
404
332
539
709
1254
1078
1407
1599
1874
2107
203
364
399
564
767
1023
996
1525
1241
1476
1.97
1.17
6.27
16.47
19.03
29.11
22.52
41.96
21.99
58.62
1.81
4.39
6.55
10.69
19.80
24.82
29.00
33.65
30.03
21.57
-------
Table 8
Heavy Duty Gasoline Engine Test Procedure
Emission Concentrations
Standards HC ppm C0%
1969-1971 California 275 1.5
and Federal thru 1973
1972 California 180 1.0
Typical Federal Certification levels - Chrysler 413 engine
HC ppra C0%
1972 model year 85 .74
127 .77
1973 model year 83 .59
119 .37
127 .77
29-Passenger Gasoline-Powered Bus (Approximation)*
HC ppm C0%
Test of 5-7-73 123.2 .76
Test of 5-16-73 126.6 .92
*These results were calculated using that FederaJ.—_ 13-mode test data
for which the manifold vacuum was approximately the same as required
by the heavy duty gasoline engine test procedure.
-------
Table 9
Heavy Duty Gasoline Engine Test Procedure
Grains Per Brake Horsepower-Hour
Standards HC CO NOx HC -I- NOx
1974 Federal & '73-'74 California 40 16
1975-76 California 30 10
1977 California 25 5
Typical 1974 Federal Certification
levels Chrysler 413 engine 14.7 14.05
(two tests)
Federal 13-mode procedure
29-Passenger Gasoline Bus
Test of 5-7 & 5-8-73 7.7 40.2 11.2 18.9
Test of 5-16-73 8.6 66.5 13.5 22.1
1974 Federal Heavy Duty Gasoline
Engine Test Procedure*
29-Passenger Gasoline Bus
Test of 5-7 & 5-8-73 5.1 57.8 8.0 13.1
Test of 5-16-73 5.5 61.6 15.9 21.4
*These results were calculated using that Federal 13-mode test data for which the
manifold vacuum was approximately the same as required by the heavy duty gasoline
engine test procedure.
-------
Table 10
29-Passenger Gasoline-Powered Bus
1975 Federal Test Procedure (Cold Start) Mass Emissions
Grains per Mile
Date HC CO CO2 NOx Fuel Economy
5-11 7.75 171.12 1028.8 15.34 5.31 6.70
* Test cycle fuel economy: miles * ca;bon 'f' ^action * f^ density
-1 J sum of carbon wt.fraction bags 1/2,3 emissions
** Weighted fuel economy : carbon wt fraction x fuel density
y -^ sum of carbon wt. fraction x emissions gm/mi
-------
Table 11
29-Passenger Gasoline-Powered Bus
Ann Arbor-1 Bus Route, CVS Procedure Mass Emissions
Grains Per Mile
Date HC CO CO2 NOx
Fuel Economy
(mi/gal)
Cold Start 5-4* 19.17 286.18 1398.1 15.71
Hot Start 5-4* 17.28 280.91 1287.4 15.08
Cold Start 5-7 18.13 285.94 1164.8 17.27
Cold Start 5-8* 22.19 277.71 1289.3 24.60
Hot Start 5-8* 21.04 283.82 1219.1 24.19
4.65
4.97
5.30
4.93
5,12
* Cold start and hot start used same bag
da+-a after first 390 seconds
-------
Table 12
29-Passenger Gasoline-POwered Bus Mass Emissions
Steady State Modes
NOx
0
1.26
4.11
9.10
11.35
19.94
26.46
Grams Per Minute
Mode
Idle
10 mph
20 mph
30 mph
40 mph
50 mph
60 mph
Idle
10 mph
20 mph
30 mph
40 mph
50 mph
60 mph
HC_
3.52
2.08
1.76
1.67
1.81
2.26
2.03
N/A
12.71
5.45
3.38
2.79
2.83
2.11
CO
62.40
46.61
18.35
13.13
34.95
43.03
41.92
Grains
N/A
284.62
56.70
26.51
53.99
53.98
43.31
co2
77.
192.
274..
404.
511.
752.
988.
Per Mile
N/A
1171.
848.
816.
789.
944. .
1023.
N/A Fuel Economy
MPG
7.67 5.35
12.69 9.30
18.37 10.22
17.53 10.05
25.02 8.55
27.42 8.08
-------
Table 12 cont.
Grains Per Brake Horsepower Hour
Mode
Idle
10
20
30
40
50
60
mph
mph
mph
mph.
mph
mph
HC
CO
co2
NOx
HP
N/A
22.
7.
2.
2.
1.
1.
28
21
78
03
88
21
499
75
21
39
35
24
.0
.06
.86
.36
.88
.97
2053..
1123.
673.
575.
627.
590.
13
16
15
12
16
15
.44
.83
.15
.78
.63
.81
5
14
36
53
71
100
.6
.6
.0
.2
.9
.4
-------
Table 13
TC-25 and TC-29 Bus
Rolling Resistance Values
TC-29 Gasoline Bus
TC-25 ORC Bus
MPH
10
20
30
40
50
60
Road Test (HP)
3.1 (1)
8.9
21.7
41.5
64.9
94.4
DYNO Road Load HP
5.8 (2)
14.5
26.3
49.2
75.6
105.9
Predicted HP
3 (3)
9
20
37
65
104
Experimental HP
7.5 (4)
16
27
1) EPA road test
2) typical road load for Ann Arbor Bus route and LA-4
3) bus manufacturer's predicted values
4) Sundstrand Aviation measured values in road tests
-------
Table 14
TC-29 Gasoline-Powered Bus
Noise Tests
Per
SAE RP J 366
Full Throttle Acceleration
Run No. Noise Level^ EPN Decibels
1 92.5
2 93.7
3 94
4 93.5
------- |