72-14
       EMISSIONS FROM THE WORCESTER
       POLYTECHNICAL INSTITUTE (WPI)
                 HYBRID
                October 1971
           H.  Anthony Ashby
    Test and Evaluation Branch
Mobile Source  Pollution Control Program
    Office of  Air Programs
     Environmental Protection Agency

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Background

The WPI Electric Hybrid was entered in the 1970 Clean Air
Car Race by students from Worcester Polytechnic Institute
and was the \vinner of the Hybrid Division of the Race..  A
contract was arranged so that the car could be more thor-
oughly evaluated, using the 1972 Federal Test Procedure,
at EPA facilities in Michigan.
Control Techniques

The WPI Hybrid is basically an electric car with on-board
charging capability.  Power is stored in 20 six-volt
batteries wired in series, and is transmitted via a DC
traction motor and heavy duty propeller shaft and differs
ential to the rear wheels.  The generator for recharging
the batteries is powered by an internal combustion Jeep
V6 engine of 225 cubic inch displacement.  Emission controls
on the engine include air injection into the exhaust mani-
folds, catalytic reactors, and exhaust gas recirculation.
The engine burns lead-free gasoline to protect the catalysts.

Engine speed is maintained between 1800 and 2200 rpm.   The
load on the engine is also kept relatively constant because
the demands for power, such as during accelerations, are met
by drawing from the batteries.  Such a design has the  poten-
tial to produce low emissions.

The vehicle weighed about 4500 pounds and was tested at an
inertia weight of 4500 pounds.
Test Program

The vehicle was delivered to the EPA laboratory at Willow Run
Airport on April 7, 1971.  The students who delivered the car
demonstrated the vehicle operating procedures to GAP test
personnel.  Dynamometer testing required a driver to follow
the speed-time schedule and another person to control engine
speed and various electrical parameters.  Testing concluded
on May 8 due to increasing amounts of heat and smoke from
the vehicle's electrical apparatus.

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                                2.
The car was run on the 1972 Federal Test Procedure and
on the 7-mode procedures using an inertia weight of
4500 pounds.  The 1972 FTP is a chassis dynamometer
procedure consisting of a cold start, the LA-4 driving
schedule and the constant volume sampling (CVS) method
for collecting a diluted sample of the exhaust over the
entire start and driving operation.

The 7-mode procedures employ a repeating 7-mode driving
cycle.  The 1970 Federal Test Procedure uses continuous
analysis of the undiluted exhaust over seven repeats of
the cycle.  The emission concentrations are averaged at
several discreet intervals during each cycle and then
multiplied by factors reflecting fuel-air ratio, engine
air flow rates and time in each mode during actual driving
to yield an average concentration during each cycle.  The
mass emissions are calculated from the concentration data
using a formula based on vehicle weight.  The 9x7 test
uses nine repeats of the 7-mode cycle, with the CVS method
of sample collection.

In the 1970 FTP, all exhaust constituents are analyzed by
NDIR instruments.  In the CVS procedure NDIR is used for
determining CO and CC>2 , a flame ionization detector (FID)
for unburned hydrocarbons (HC) and a chemiluminescence (C.L.)
Instrument for nitrogen oxides (NOX).


Results
The mass emissions data, presented in Table 1, were
relatively high.  This may have been due to failure or
poisoning of the catalysts or to malfunction of the air
pumps or EGR system.  The high emissions could also have
been caused by a malfunction of the electrical controls
resulting in the I. C. engine being operated at too high
a load or at some other non-optimal condition.

Mass emissions of NOX from the C. L. instrument are
presented as NC>2, corrected to a humidity of 75 grains.
On test number 12-1521, the lower HC emissions are due
to the fact that it was a hot start test.

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                              TABLE  1








                         WPI Electric Hybrid



                           Mass Emissions
Test No.
12-1456
^-1457
12-1502
12-1520
12-1521
12-1567
6-0632
Type
72
72
72
72
72
Hot
9
70
FTP
FTP
FTP
FTP
FTP
Start
x. 7
FTP
HC
gm/mile .
3.46
5.84
1.08
1.14
.32
2.85
.35
CO
gm/mile
12
11
20
15
15
3
1
.06
.04
.39
.68
.12
• 99
.27
C02
gm/mile
1053
1182
1763
1542
1707
869

.2
.7
.8
.0
.0
.6

-gm/mlle
6
6
11
11
•«
13
9
.53
.94
.26
.44
.0.0
.82
.16*
* NO only., determined by NDIR.

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