77-10 EAB
Emissions and Fuel Economy Tests of the
University of Florida Hybrid Bus
December, 1977
Environmental Protection Agency
Office of Mobile Source Air Pollution Control
Emission Control Technology Division
Technology Assessment and Evaluation Branch
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Background
Several years ago the University of Florida began studies of hybrid
vehicles under the sponsorship of the State of Florida Department of
Transportation. Initially they designed and built a small gasoline-
electric hybrid automobile. The program was later expanded to the
design and construction of a hybrid diesel-electric bus with funding
provided by UMTA for the demonstration phase of the project.
Extensive testing of the bus was conducted over the last two years. The
vehicle was also placed in service in Gainesville for a considerable
part of this time. In January 1977 UMTA asked EPA to conduct emission
and fuel economy tests of the hybrid bus.
Due to the limited availability of test facilities, only a short test
sequence was planned. In addition, the University of Florida personnel
involved with the project and needed for vehicle testing are full time
students and faculty. Thus they were unable to support a long term
testing plan.
As a result, a complete evaluation of the hybrid bus' emissions and fuel
economy was neither planned nor conducted. The conclusions drawn from
this program are, therefore, necessarily of limited applicability and
are thus neither a comprehensive evaluation of either the test vehicle
or the hybrid powerplant concept. A complete evaluation of the emissions
and fuel economy of this hybrid bus would require more replicate testing
and more types of tests than could be performed.
Abstract
As a hybrid vehicle the bus performed well with minimal problems. For
the Ann Arbor Bus Route, the hot test emissions for HC, CO and NOx were
7.07, 5.00 and 11.59 grams/mile while achieving 8.4 miles/gallon. The
Univ. of Florida Bus Route, UMTA cycle and NYC cycle were also run to
evaluate emissions. Results for these cycles were comparable.
Vehicle Description
The test vehicle was designed to be a prototype hybrid electric urban
transit vehicle. The power system consists of a four cylinder diesel
engine driving an alternator to charge the batteries. Electric power is
taken from the batteries to power the electric motor which then drives
the vehicle. Thus the bus can be operated as an all electric vehicle or,
with the engine running, as a hybrid vehicle. The University of Florida
personnel feel that with proper selection and design of components, a
hybrid diesel-electric bus offers significant advantages as an urban
transit vehicle.
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-2-
The bus chassis is a standard Electrobus (an all electric bus) chassis
that has been re-engineered and rebuilt for hybrid use. It uses a 37.5
kW (50 hp) DC electric motor to move the vehicle. A four cylinder 3590
cc John Deere industrial Diesel engine was mated to an Onan 30 kW gene-
rator. This engine is an open chamber Diesel that was designed for use
as a stationary powerplant. It is governed to run at 1800 rpm and is
used to drive the alternators.
The Onan generator consists of two 42 volt 3 phase alternators which are
used to charge the two 630 amp hr batteries. Power is drawn from the
batteries by the electric motor. The D.C. motor is series wound - the
field coil is in series with the armature - thus it uses maximum field
and armature current at stall and therefore generates maximum torque at
stall.
The alternator power output is controlled by an automatic circuit which
is designed to maintain the batteries at a constant voltage. However,
during maximum acceleration, the voltage drop is so great that safety
circuits limit the alternator power output to 10 kW. Thus, in practice
the automatic circuit reduces the power available to a level considerably
below maximum power output. To prevent this, during transient operation,
the automatic circuits are manually overriden and the alternator is then
manually set to a fixed power output.
The vehicle operation is regulated by a controller. It consists of
multiple contact relays that are tripped in sequence by micro-switches
at the accelerator pedal. The controller varies the motor armature
resistance, field configuration, and field resistance. It places the
batteries in parallel (low speed) then in series (high speed) configu-
ration to obtain seven discreet steps of power. Some dynamic braking is
achieved by the controller switching the motor to a generator and then
dissipating the power through resistor banks.
A detailed description of the vehicle is given in Appendix A. The
control system schematic and vehicle layout are also in Appendix A.
Pictures of the vehicle are on the following page.
Test Procedures
No prescribed gaseous emission test procedures exist for this type of
vehicle. However, inasfar as possible the methods given in the 1977
Federal Test Procedure ('77 FTP, part 40, combined Federal Register,
July 1, 1976) were followed. All tests were performed with the engine
running (i.e. no cold or hot start tests). The tests included the Ann
Arbor Bus Route (AA-1), University of Florida Bus Route (U of F), UMTA
Cycle, New York City (NYC) Cycle, and Steady State.
All tests were conducted on a large roll electric chassis dynamometer
and used the constant volume sampling (CVS) procedure. This procedure
gives exhaust emissions of HC, CO, CO and NOx in grams per mile. Fuel
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-3-
. n
tesasL.-^i'jjrel J
- Front view of completed Urban Transit Vehicle
- Front quarter view of completed Urban Transit Vehicle
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-4-
economy was calculated by the carbon balance method. Because the fuel
used was diesel #2, a heated flame ionization detector (HFID) was also
used to measure HC. Otherwise the heavy hydrocarbons would condense out
in the sampling system and not be measured.
All testing was performed on a 48" single roll chassis dynamometer.
This is a large truck dynamometer which is able to simulate inertia
weight and road load electrically. Thus the road load horsepower curve
is adjustable to the specific type of vehicle. The road load curve was
adjusted to conform to that measured by U of F personnel during road
tests. No additional loads were imposed to simulate a vehicle air
conditioning load.
The bus had a curb weight of 15,200 pounds. Allowance for a 50% load
factor (10 passengers) would mean a test weight of 16,700 pounds.
However, all tests were conducted using an inertia weight of 15,000
pounds since most tests by the University of Florida personnel were at
this weight. This inertia weight allowed U of F and UMTA to correlate
with previous testing. In addition, later models of the basic bus
chassis weigh less and thus a chassis specifically designed for hybrid
use could be expected to weigh less than the present chassis.
Test Program
The U of F hybrid bus has a top speed of 64 km/hr (40 mph). Therefore
the standard test cycles such as the Federal Urban Driving Cycle or
highway cycles with top speeds of 88 to 96 km/hr (55 to 60 mph) were
inappropriate.
Therefore, lower speed cycles were chosen. They were:
AA-1 - 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 Trans-
portation Authority. The cycle is not an official test cycle, but
rather is used as an experimental tool for evaluating buses.
U of F - is a speed versus time trace generated by U of F by following
buses with a vehicle equipped with a fifth wheel. This trace was
then linearized to a straight line speed versus time trace for ease
in computer modeling.
UMTA Cycles - simple speed versus time traces used to evaluate
buses. The two cycles used differ only by the addition of 4 seconds
of added cruise time.
NYC Cycle - a low speed versus time trace generated during traffic
studies in NYC. This cycle has higher acceleration (4.0 mph per
second) and deceleration rates (5.1 mph per second) than the 3.3
mph per second of the FTP.
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-5-
Speed versus time plots of these traces are given in Appendix B. Their
key features are summarized below. For comparison the Federal Urban and
Highway Cycles are also given below.
Cycle
AA-1
U of F
UMTA slow
UMTA fast
NYC
Urban
Highway
Length
Miles
5.49
5.36
0.13
0.16
1.18
7.45
10.24
Average
Speed MPH
11.3
10.9
9.6
10.8
7.1
19.7
48.2
Top
Speed MPH
33.2
34.2
25.0
25.0
27.7
56.7
59.9
Stops
per mile
4.55
2.43
7.56
6.26
9.33
2.42
0.10
% Time
Idle
20.8%
29.7
41.3%
38.2%
42.1%
19.5%
0.5%
Cycle
Time
29.2 rain
29.5 min
0.8 min
0.9 min
10.0 min
22.9 min
12 . 8 min
The bag sample times for the AA-1 and U/F cycles were chosen to permit
further evaluation of the driving cycles and prevent overfilling of the
CVS sample bags. The values are:
Bag 1 Bag 2 Bag 3
AA-1 1.23 miles 6.5 min 1.01 miles 8 min 3.15 miles 14.5 min
U of F 1.85 miles 10 min 2.52 miles 13 min 0.99 miles 6.3 min.
An electric hybrid vehicle can store electrical energy in one cycle and
expend it in another. To properly evaluate an electric hybrid vehicle's
emissions and fuel economy there must be no net change in vehicle's
battery state of charge (energy storage) over the driving cycle chosen.
In addition, tests must be conducted with the batteries at a represen-
tative level of charge since the vehicle's charge/discharge efficiency,
fuel economy, and performance are dependent on the level of energy
storage.
A previous EPA test program had shown the difficulty in quickly performing
cold start tests of an electric hybrid vehicle while simultaneously
properly maintaining the battery state of charge. Since a limited
amount of facility time and personnel were available, only hot tests
were planned. In addition, to eliminate warm-up effects on emissions,
the engine and tires were warmed up prior to emission tests. This
engine warm up was accomplished without charging the batteries. The
tires were warmed up by motoring the vehicle with the dynamometer. No
hot start tests were attempted. The engine was running prior to the
start of each cycle. The above considerations should not bias the
results greatly since it is anticipated that cold starting would represent
only a small portion of a bus' daily duty cycle and, once started, the
bus would continuously repeat its duty cycle.
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The specific gravity and voltage of each battery were measured before
and after each emission test. Those results were used to determine the
vehicle's battery state-of-charge prior to each test and the net change
in charge.
Prior to testing, the batteries were charged by using the bus alternator.
The batteries were charged until they would accept energy only at a very
low rate even when the maximum safe alternator output voltage was used.
Results
The exhaust emissions data are summarized in Table 1 for each of the
driving cycles. No Federal emission standards exist for this type of
vehicle or for these types of driving cycle. Detailed results for these
tests and the steady state tests appear in Appendix B.
The results in Table 1 are uncorrected for net energy storage or expenditure
during the test cycle. However, the battery conditions, as measured by
specific gravity and voltage did not change appreciably during testing.
(See Appendix B, Tables B-4 and B-5).
At the conclusion of testing the batteries were discharged by driving
the vehicle for 30 minutes at 30 mph. Attempts were made to partially
map the fuel/battery energy relationships by charging the batteries and
measuring the fuel consumed. (See Appendix B Tables B-4 and B-5). It
was hoped that this would allow the vehicle charge efficiency to be
determined as a function of battery state of charge. At the battery
charge levels at which emission testing was performed, the data shows a
large fuel consumption with little change in battery charge. Straight
forward application of these results to the AA-1 and U of F cycles would
have lead to an unrealistic decrease in fuel economy for the AA-1 cycle
and an unrealistic gain in fuel economy for the U of F cycle.
Other results tend to show that the effects of battery energy storage on
the vehicle fuel economy were minimal. Again referring to Tables B-4
and B-5, the batteries were brought from a discharged state of 85.11
volts at 1.164 specific gravity to 87.30 volts at 1.224 specific gravity.
This consumed 1.69 gallons of Diesel fuel. This change in battery
energy storage was considerably greater than that experienced during any
test cycle. This implies the effects on fuel economy, due to the small
changes in battery conditions during testing, should be minimal.
Therefore, because of the conflicting data, it was not possible to correct
the fuel economy results for the small changes in battery state of charge.
Similar problems were encountered during previous tests of a hybrid
vehicle (Report 75-14). These difficulties were overcome only by the
use of additional test equipment and a considerably larger test program.
Accurately investigating and accounting for these effects on the bus
would require a much broader and more extensive testing program. There-
fore, it appears that hybrids cannot be effectively tested with existing
equipment.
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Table 1 - Mass Emissions
0 of
grams per mile
(grams per kilometer)
Fuel Economy
Total Battery Change Over Tests
Battery Any Cell
Cycle
AA-1
U of F
U of F**
UMTA slow
UMTA fast
NYC
Tests
3
3
4 .
1
1
3
HC*
7.
(4.
6.
(3.
3.
(2.
8.
(5.
7.
(4.
12.
(7.
07
39)
34
94)
39
11)
72
42)
32
55)
36
68)
CO
5
(3
4
(2
1
(1
5
(3
5
(3
8
(5
.00
.11)
.29
.67)
.99
.24)
.70
.54)
.03
.13)
.92
.54)
CO 2
1200
(746)
1207
(750)
885
(550)
1743
(1083)
1450
(901)
1864
(1158)
NOx
11.59
(7.20)
12.10
(7.52)
11.89
(7.39)
19.08
(11.86)
15.45
(9.60)
17.24
(10.71)
(fuel consumption)
8.4
(28.0
8.3
(28.2
11.4
(20.7
5.8
(40.6
6.9
(34.1
5.4
(43.9
miles/gal
litres/100
miles/gal
litres/100
miles/gal
litres/100
miles/gal
litres/100
miles/gal
litres/100
miles/gal
litres/100
km)
km)
km)
km)
km)
km)
Voltage Specific Gravity
-.98 -.0116
.40 .0114
-.96 -.0145
-.0039 *
-.0039
-.0059
**
HC values given are for heated flame ionization detector
Test series consists of electric (engine off) , hybrid,
electric (engine off), hybrid mode of operation. Emissions
and fuel economy are adjusted for total miles driven. This
includes cycles with engine off. Bag 2 values for test
78-1811 assumed to be same as test 78-2811.
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-8-
The effects on emissions of the above load changes would probably be
minimal for the AA-1 cycle and the U of F cycle. Referring to the
steady state values of Table B-3, it appears that except at idle, the
emissions do not vary appreciably with a small change in engine load.
EPA has previously tested several buses using the AA-1 route and a
version of the Federal Heavy Engine Certification procedure adapted for
a chassis dynamometer. Compared to these vehicles the hybrid bus results
were encouraging (i.e. no better or worse). However, none of these
vehicles would be an ideal choice for fuel economy comparison since they
are either much larger or do not use a diesel engine. Mercedes Benz
markets a small (13 to 19 passenger) Diesel bus. Their fleet users
achieve fuel economies of between 8 and 13 mpg. However, these results
are for a slightly smaller bus over unknown duty cycles.
The relatively good fuel economy for the bus while driving the U of F
cycle in the electric (engine off) hybrid mode may not be as good as it
would appear. Measurement of fuel consumption with a fuel meter showed
fuel consumptions 6% to 20% higher than the CVS results for the electric/
hybrid test. The 20% discrepancy occurred on bags 1 and 3 of test 78-
2810. This did not occur on the replicate test, 78-2811 or on bag 2 of
test 78-2810. Therefore, both emissions and fuel economy may be in
error. The scheduling problems and heavy testing load prevented addi-
tional tests from being performed which could have investigated this
problem further. However, no additional reasons have been found to
invalidate the results, so they are reported herein.
Problems were encountered in testing. The vehicle has excellent low
speed acceleration and is able to follow the fastest scheduled accel-
erations below 20 mph. After this point, there is a decrease in the
vehicle acceleration rate and the vehicle cannot follow all driving
cycles (see driving cycles in Appendix C). The controller did cause
some difficulty in following the driving cycle. Since it works in
discrete increments, it was sometimes difficult to hold an intermediate
speed over a portion of the driving cycle. In addition one controller
relay was malfunctioning and there was therefore a large jump in power
at times. The high charging currents required for the AA-1 and U of F
cycles caused many of the special catalytic battery caps to blow off.
The vehicle is not equipped with power steering and is very difficult to
manuever, however, this created only minimal problems for the dynamometer
tests.
In previous tests of diesel fueled vehicles (cars and buses), the ratio
of the hydrocarbon values for the heated FID to the CVS ranged from 1.01
to 1.8 for most transient test cycles. For this vehicle there was a
marked change in this pattern. The ratio was between 2.5 and 3.5 for
all transient tests. For steady state tests the values ranged from 1.6
to 3.2. This implies either that the combustion process relating to HC
formation is considerably different for this vehicle, or, since the
engine was designed for stationary power plant usage, the engine's basic
control of HC is poor during transient cycles.
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-9-
Conclusions
As a hybrid vehicle, the bus functioned well with minimal problems for a
prototype vehicle. The vehicle fuel economies are comparable to other
buses. For the hot tests, using the AA-1 route, the vehicle's emissions
for HC, CO, and NOx were 7.07, 5.00, and 11.59 grams per mile respectively.
Vehicle fuel economy was 8.4 miles/gallon. The vehicle showed potential
for fuel economy improvements by operating it as an electric/hybrid
vehicle. However, there were additional fuel economy results which
indicated little or no change. Lack of facility time prevented this
problem from being explored further.
The change in the ratio of HC measured by heated FID to CVS values is
noteworthy. Previously, for most vehicles test results showed the ratio
to be from 1.1 to 1.6. However for tests of this vehicle, it varied
from 2.6 to 3.5.
The emissions and fuel economy test results for hybrid vehicles are
difficult to measure due to the capability of the vehicle to store
electrical energy in one cycle and discharge in another. The change in
charge/discharge efficiency, fuel economy, and performance with vehicle
state-of-charge further complicates testing. Therefore, the hybrid
results must be considered suspect until accurate methods exist for
determining the energy levels in a battery.
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Appendix A
Test Vehicle Description
University of Florida - DOT Urban Transit Vehicle
Electric Propulsion Unit
Prime Mover
Alternator
Rectifiers
Batteries
Controller
Engine
Manufacturer
Type
Bore x Stroke
Displacement
Compression Ratio
Power @ rpm
Fuel Metering
Fuel Requirement
Drive Train
Transmission
37.3 kW (50 hp) , series would electric motor,
with two fields - Tork Link Corp.
3 phase A.C., 30 kW, 40 V RMS line to line,
1800 RPM, modified Onan Corp model 30-DDA-15R
with 2 independent outputs
Two SCR bridge type, 400 V-370 AMP Westinghouse
model G.E. 1987d
Two 21 cell Gould Electric Vehicle type 63E-W1,
630 amp hr (6 hr rate), 42 V, weight 1850 Ibs each.
Contactor with relays. Provides 7 driving modes
plus one for dynamic breaking
John Deere, Series 300, Model 4219D
4 stroke, Diesel cycle, OHV, inline, 4 cylinder
102 mm x 110 mm (4.02 in x 4.33 in)
3590 cc (219 cu. in.)
16.3:1
44.7 kW (60 hp) @ 1800 rpm
Fuel injection
Diesel No. 2
None, direct drive by electric motor (Diesel
engine with alternator is used to charge battery)
Axle Ratio
6.8:1
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Appendix A (cont.)
Chassis
Basic Chassis
Size
Type
Tire Size
Curb Weight
Passenger Capacity
Emission Control System
Basic Type
Durability Accumulated
on System
Re-engineered model 20 Electrobus, mfg. by
Tork Link
7.493 meters (24 ft. 7 in.) long
2.337 meters (92 in.) high
2.565 meters (101 in.) wide
Rear engine, rear drive.
8.25 x 15, 14 ply rating, Michelin steel
belted radials
6895 kgm (15,200 Ibs)
15 including driver due to experimental seating
arrangement. Vehicle designed for 20 with
standard seating arrangement.
None, diesel engine operated at 1800 rpm at
all times, it is an open chamber Diesel
2000 miles (estimated)
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FIGURE 1 -
HYBRID SYSTEM SCHEMATIC
o
«-> *H
rt o
^ M
CU 4-1
c e
i-H
rH
O
C
O
U
Rectifier
Battery
o
4->
-------
Bag 2^»- |*-Bag 1
Start
END
Ann Arbor Bus Route
Start
Bag 3 I-*- Bag 2 -
fTH
University of Florida Cycle
(W
Appendix B - Bus Test Cycles
-------
25 MPH
END
END
UMTA Fast
Start
25 MPH
UMTA Slow
UMTA Cycles
Start
TO
NYC Cycle
Appendix B (cont.) - Bus Test Cycles
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Table B-l
Ann Arbor Bus Route
Mass Emissions - grams per mile
Test No.
78-1786
78-1787
78-1788
Bag 1
HC HFID CO C02 NOx
2.33 8.03 5.85 1130 11
2.73 8.82 6.21 1104 10
2.15 6.99 4.67 1214 12
Test
.03
.08
.57
No.
78-1786
78-1787
78-1788
MPG HC HFID
8.9 3.68 12
9.1 3.96 11
8.3 3.37 9
.28
.89
.92
Bag
CO
8.69
7.98
5.96
2
C02
1656
1722
1944
Ann Arbor Bus Route
Total Mass Emissions - grams
HC HFID CO C02
2.38 7.94
2.45 6.42
2.59 6.85
5
5
4
.67
.10
.23
1140
1187
1273
NOx
15
16
20
per
NOx
10.
10.
13.
.52
.00
.64
mile
83
74
19
MPG
6.
5.
5.
1
8
2
MPG
8.
8.
7.
8
5
9
HC
HFID
Bag 3
CO
CO?
NOx
MPG
1.99 6.51 4.64 978 9.25 10.3
1.86 6.17 3.77 1049 9.32 9.6
2.51 5.81 3.51 1081 11.06 9.3
Ul
I
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Table B-2
University of Florida Bus Route
Mass Emissions - Grams per mile
Bag 1
Bag 3
Test No.
78-1790
78-1791
78-1792
Test No.
78-2810*
78-2811*
HC HFID CO C02 NOx MPG HC HFID CO CO? NOx MPG HC HFID
1.93 6.71 4.14 1371 14.37 7.4 1.65 4.66 2.72 943 9.97 10.7 2.66 8.03
2.35 6.23 4.54 1201 11.99 8.4 2.48 6.27 3.90 1288 12.95 8.2 2.94 7.85
2.45 6.45 4.55 1222 12.32 8.2 2.36 6.10 4.51 1048 9.40 9.6 2.79 7.55
University of Florida Bus Route
Total Mass Emissions - grains per mile
Test No. HC HFID CO C02 NOx MPG
78-1790 1.93 5.99 3.62 1210 12.66 8.3
78-1791 2.52 5.54 4.52 1260 12.94 8.0
78-1792 2.47 6.49 4.73 1150 10.71 8.7
University of Florida Bus Route
Electric/Hybrid Mode of Operation
Mass Emissions - grams per mile
Bag 1 Bag 2
HC HFID CO C02 NOx MPG HC HFID CO O>2 NOx MPG HC HFID
1.73 9.61 3.34 1586 20.97 6.4/4,9 1.98 6.17 3.15 1679 22.17 6.0/5.6 2.70 8.06
2.97 6.96 5.68 1886 25.71 5.3/5.0 4.01 8.06
University of Florida Bus Route
Electric/Hybrid Mode of Operation
Total Mass Emissions - grams per mile
Test No. HC HFID CO C02 NOx MPG
CO CO 2 NOx MPG
4.94 1589 16.31 6.3
6.06 1451 14.69 6.9
5.67 1272 11.00 7.9
Bag 3
CO C02 NOx MPG
3.95 1868 24.87 5.4,
6.23 2268 32.78 4.4,
3.37
78-2810 2.03 6.80
Mass emissions are not adjusted to include mileage for cycle in electric mode.
1682 22.44 6.0
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-17-
Table B-3
Mass Emissions - grams per mile
Test Type
UMTA slow
UMTA fast
NYC
NYC
NYC
Steady State
Idle*
Steady State
25.5 mph
Steady State
25.7 mph
Steady State
33.0 mph
Steady State
41.8 mph
Test No.
78-1793
78-1793
78-1789
78-1789
78-1789
78-1804
78-1804
78-1805
78-1805
78-1805
HC
2
2
4
4
4
52
1
2
1
1
.99
.52
.12
.35
.09
.65
.76
.07
.53
.06
HFID
8
7
12
12
11
146
3
3
2
3
.72
.32
.89
.27
.95
.54
.48
.38
.38
.36
CO
5
5
9
8
8
89
3
2
1
1
.70
.03
.07
.80
.91
.36
.59
.12
.06
.83
CO?
1743
1450
1991
1818
1786
4696
498
496
502
553
NOx
19.
15.
19.
16.
15.
237.
12.
19.
25.
7.
08
45
15
67
94
12
70
61
10
54
MPG
5.8
6.9
5.0
5.5
5.6
0.49
20.0
20.0
20.0
18.2
*Values are gms/hr and gal/hr.
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-18-
Table B-4
Vehicle Battery Statje of Charge Summary
Date
5/10
5/11
5/12
5/12
5/12
5/13
5/13
5/13
5/13
5/14
5/16
5/23
5/27
6/14
6/15
6/17
6/20
Avg. Cell Volts Total Volts
2
Before A
Before U/F
Before NYC
14 cells before NYC
14 cells before UMTA
Before Steady State
14 cells before Steady State
14 cells before discharge
4 cells after discharge
Before charge
After charge
14 cells before charge
14 cells after charge
14 cells only before charge
14 cells only after charge
Before U/F
After U/F
2.1114 88.
2.0877 87.
2.0974 88.
2.0977
2.1011
2.0832 87.
2.0265 85.
2.0759 97.
2.0664 86.
2.0788 87.
2.0659 86.
2.1008 88.
2.0807 87.
68
70
10
50
11
19
67
30
75
24
28
Avg. Specific Gravity
1.2420
1.2305
1.2419
1.2417
1.2358
1.2281
1.2280
1.2338
1.1745
1.1636
1.2049
1.2054
1.2243
1.2170
1.2176
1.2389
1.2244
Table B-5
Vehicle Battery Change Charge Summary
-
Date Test Number
5/10 A2 78-1786, 1787, 1788
5/11 U/F 78-1790, 1791, 1792
5/12 NYC 78-1789
5/12 UMTA 78-1793 (slow & fast)
5/13 Steady State
5/14 Charge 1.04 gallons
5/23 Charge 0.65 gallons
6/15 Charge 1.02 gallons
Avg. Cell Volts Total Volts
-.0237
0.0097 0
0.0034
-.0180
0.0494 2
0.0124 0
.98
.40
.08
.63
Avg. Specific Gravity
-.0116
0.0114
-.0059
-.0078
0.0058
0.0414
0.0189
0.0006
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-19-
Table B-6
Ann Arbor Bus Route - grams per mile
HC CO CO 2 NOx MPG
20 passenger gasoline 19.16 282.37 1288 19.64 5.0
45 passenger diesel 6.2 14.0 31.5 4.6
53 passenger steam bus 3.3 7.0 8.9 1.0
Rankine cycle
13 Mode Heavy Duty
grams per brake horsepower hours
HC CO NOx HC + NOx
25 passenger Rankine cycle 2.1 20.0 2.0
29 passenger gasoline 8.1 53.4 12.4
45 passenger diesel 1.2 7.4 8.4
53 passenger Rankine cycle 0.4 2.3 2.7
77 Cal. Std. 25.0
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o
OQ
Test Cycle
Cycle
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Test Cycle
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Ann Arbor Bus Route
Appendix C - Driving Traces
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Test Cycle
UMTA Fast
NYC Cycle
Appendix C - Driving Cycles (cont.)
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I
S3
University of Florida
Appendix C (cont. )
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