LDTP-77-3
Technical Support Report for Regulatory Action
Comparison of Dynamometer Power Absorption Characteristics
and Vehicle Road Load Measurements
by
Glenn D. Thompson
and
Myriam Torres
July 1977
NOTICE
Technical support reports for regulatory action do not necessarily
represent the final EPA decision on regulatory issues. They are intended
to present a technical analysis of an issue and recommendations resulting
from the assumptions and constraints of that analysis. Agency policy
constraints or data received subsequent to the date of release of this
report may alter the recommendations reached. Readers are cautioned to
seek the latest analysis from EPA before using the information contained
herein.
Standards Development and Support Branch
Emission Control Technology Division
-Office of Mobile Source Air Pollution Control
Office of Air and Waste Management
U.S. Environmental Protection Agency
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Abstract
If dynamometer measurements are to accurately reflect the on-road
operation of a vehicle, the dynamometer must supply the appropriate
load; that is, the force required to drive the vehicle on a level sur-
face as a function of the vehicle speed.
The dynamometers currently in use at the EPA for emission certi-
fication and fuel economy measurements have a single adjustable load
parameter. Therefore, the load at any single speed, typically 50 mph,
can be adjusted. Currently, for most vehicles, the dynamometer power
absorption at 50 mph is predicted by EPA, based on previous measurements
of a large class of vehicles. The regulations do, however, provide an
opportunity for manufacturers to submit road load data and to request
the dynamometer adjustment be based on these empirical results. In this
instance no systematic error should occur at 50 mph. However, since the
dynamometer loads at all speeds other than the 50 mph set point are
subsequently determined by the load versus speed curve of the dynamo-
meter, errors may occur at other speeds.
This report presents vehicle road load force versus speed curves
and Clayton dynamometer force versus speed curves. The vehicle road
load force data were collected in the recent road load project, where
the vehicle road load, as a function of speed, was determined for sixty-
three light-duty vehicles. These vehicles were chosen to represent the
sales distribution of light-duty vehicles. The dynamometer data were
obtained from the six EPA certification dynamometers. These data were
collected and made available by the EPA Quality Control Development
Section.
The dynamometer data is first used to generate an equation to
represent an average emission dynamometer. The variations of the indi-
vidual dynamometers about this average dynamometer curve are discussed.
Subsequently, each vehicle curve is compared to this average dynamometer
curve. Variations between different vehicles are discussed, and the
possible intrinsic error caused by differences between the shape of the
dynamometer force versus speed curve and the typical vehicle road load
curve is investigated.
It is concluded that:
1. Variations among different EPA dynamometers exist and are
statistically significant.
2. Differences exist among the appropriate dynamometer road load
simulation curves for different vehicles. The observed vari-
ations among the vehicles are greater than the dynamometer
variations.
3. The current EPA dynamometers appear to supply insufficient
load at low speeds to correctly simulate the average vehicle
road experience. This conclusion is, however, very dependent
on the tire-twin roll dynamometer interaction i.e., the assump-
tion that two tires dissipate as much power on the dynamometer
as four tires dissipate on the road.
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I. Purpose
This report presents vehicle road load force versus speed curves
and Clayton dynamometer force versus speed curves. These curves are
compared, and the possible intrinsic error caused by differences between
the shape of the dynamometer force versus speed curve and the vehicle
road load curve is investigated.
II. Introduction
When vehicle exhaust emission tests or vehicle fuel consumption
measurements are performed on a chassis dynamometer, the dynamometer is
usually adjusted to simulate the road experience of the vehicle. Speci-
fically, if the dynamometer measurements are to accurately reflect the
on-road operation of the vehicle, the dynamometer must supply the
appropriate load; that is, the force required to drive the vehicle on a
level surface as a function of the vehicle speed.
The dynamometers currently in use at the EPA for emission certifi-
cation and fuel economy measurements have a single adjustable load
parameter. That is, the load at any single speed, typically 50 mph, can
be adjusted. Currently, for most vehicles, the dynamometer power absorp-
tion at 50 mph is predicted by EPA, based on previous measurements of a
large class of vehicles. The regulations do, however, provide an oppor-
tunity for manufacturers to submit road load data and to request the
dynamometer adjustment be based on these empirical results. In this
instance no systematic error should occur at 50 mph. However, since the
dynamometer loads at all speeds other than the 50 mph set point are
subsequently determined by the load versus speed curve of the dynamo-
meter, errors may occur at other speeds. The possible systematic nature
of these errors and their magnitude are discussed.
Errors can also occur because of variations in the characteristics
of different dynamometers. The magnitude of these errors are discussed,
and their effect on fuel economy is considered.
III. Discussion
This report is based on the data collected in the recent road load
project and on dynamometer data from the EPA Quality Control Development
Section. The dynamometer data is first used to generate an equation to
represent an average emission dynamometer. The curve of this "average
dynamometer" is then compared with each of the vehicle curves.
A. The Dynamometer Characterization
The purpose of this section is to develop an equation to represent
the average emission dynamometer. In the process of developing this
equation the variations between dynamometers can be observed and will be
discussed. All dynamometer data were supplied by the EPA Quality
Control Development Section. Two data sets were supplied, the first was
speed versus time data during dynamometer coast downs. These data were
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analyzed to give the total power absorbed by the dynamometer. Dynamo-
meter power absorber torque versus speed was the second data set. These
data were used to calculate indicated dynamometer torques and then, by
subtraction from the total torque calculated from the coast down data,
the dynamometer residual friction could be obtained.
1. Total Force Measurements
Speed versus time data were obtained from the EPA Quality Control
Development Section for the six EPA certification dynamometers. The
dynamometers were adjusted»to simulate a vehicle weighing 4000 pounds
using the automatic road load control mode of the dynamometers .
The measurements were made by placing a vehicle on the dynamometer
rolls, warming the dynamometer up, and then driving the dynamometer up
to some speed in excess of 60 mph. The vehicle was then moved from the
dynamometer front roll and the speed of the front roll recorded on a
strip chart recorder as this roll freely decelerated. The front roll
periferal speeds, at five second intervals, were then read from the
strip chart.
The total dynamometer force was then calculated by numerically
differentiating the speed data and multiplying by the simulated ve-
hicle mass. That is:
dv
F = ma = m -r—
dt
Av
Since the dynamometer was adjusted to simulate a vehicle weighing
4000 pounds, the mass of such a vehicle was used in the calculations.
The computed force was designated as the force operating at the midpoint
speed of the Av interval. The speeds and computed forces for each of
the six dynamometers are given in tables 1 through 6 of Appendix A.
The force data were regressed against speed for each dynamometer
individually, and then a single equation was developed by pooling the
data for all dynamometers.
The model for all the regression lines was chosen to be a second
order polynomial of the form
F = fQ + fjv + f2v2 (2)
This model was chosen because it was believed that the torque of the
power absorber would be very nearly proportional to v , while the
residual friction should be nearly constant, increasing slightly with
speed. After performing the regressions the regression coefficients
were examined. Each of the coefficients were significantly different
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from zero. Examination of the residuals for the combined data and
individually for each dynamometer seemed to support the underlying
assumptions of the model.
Extensive analysis of the data supported these theoretical expecta-
tions. Direct regression of the power absorber torques indicated this
torque is proportional to velocity squared and there is little statis-
tical confidence in any other polynomial terms. Regressions of the
friction forces appeared to be linear with no statistical confidence in
higher order terms. The friction data is, however, somewhat "noisey"
since it results from numerical differentiation and subtraction of
nearly equal quantities. It is possible that a small v term could
appear in the residual friction, caused by aerodynamic drag on the
flywheels. This component might not be detected because of the random
data error, or noise in the residual friction calculations.
In addition, exponential models of the form
F = avx (3)
were also regressed. This model was chosen because of common historical
usage. The data analysis did not indicate any superiority of the
exponential model over the polynomial model. The polynomial model was
subsequently chosen for all remaining effort because of its stronger
theoretical foundation.
The results of the polynomial regression of the pooled data were:
f» = 5.34 pounds
f.T = 0.188 pounds/(mi/hr) _
fj = 0.0283 pounds/(mi/hry
The curve represented by these coefficients is plotted in figure 1,
as are the similar individual curves for each of the dynamometers.
Figure 1 indicates that differences appear to exist between the differ-
ent dynamometers.
Using the data for speed and torque, the differences between the
dynamometers were examined by performing a two-way analysis of variance.
The two factors were dynamometer number and speed, and the measuring
variable was torque. This was based on the assumption that the differ-
ences in speed were so minor that they would not affect the results of
the analysis of variance. The results were that the dynamometers were
statistically different from each other at the 90 percent confidence
level.
Because there were slight differences in speed, in order to remove
the effect speed might have on torque, an analysis of covariance on
torque with speed as the covariate was conducted. The covariate must
fill two requirements: it must be independent of the dynamometers and it
must be correlated with torque. Speed obviously fills both requirements
since it is independent of the dynamometer, however, the torque of each
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s..
LJ
o
cc
DYNRMOMETER
CURVES
flVG DYNflMOMETER
• INDIV DYNflMOMETERS
10.
20. 30.
SPEED (MPH)
40.
50.
60.
FIGURE 1
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dynamometer is dependent on the dynamometer speed. The results of the
analysis of covariance supported the previous indication that the coef-
ficients for the individual dynamometers differed significantly. Con-
sequently, it was concluded that there are differences in the dynamo-
meters even after removing the effect of speed.
In order to assure all the above tests were meaningful, the under-
lying assumptions of normality and equality of variances of the residuals
were checked. A histogram of the residuals indicated that they were
normally distributed, and Bartletts1 test for equality of the variances
supported the constant variance assumption.
Since the dynamometers were significantly different the action of
pooling the data to compute an "average dynamometer" characteristic
curve was questioned. However, each dynamometer was well represented by
the model equation, and the variances of the residuals for each dynamo-
meter were approximately equal. Therefore, the regression equation
resulting from the pooled data may be used with confidence.
B. The Road Load Measurements
The vehicle road load, as a function of speed, was determined for
sixty-three light-duty vehicles. These vehicles were chosen to be
approximately representative of the sales distribution of light-duty
vehicles and are identified in Table 1 of Appendix B.
The coast down technique was used for all road load measurements.
The concept of this method is to determine the rate of deceleration of
a freely coasting vehicle, then, knowing the mass of the vehicle, the
road load force may be calculated by Newton's second law:
F = MA (A)
The mass, M, of equation A represents the sum of the gravitional mass of
the vehicle as tested and the "effective equivalent mass" of rotating
components of the vehicle. The acceleration A was modeled as a poly-
nomial function of velocity of the form:
A = a. + a.v + a0v2 (5)
U J- £
where:
v = the vehicle velocity
a_, a- and a« are constants determined for each vehicle.
The acceleration can, of course, be written as the derivative of the
vehicle velocity. Equation 5 can then be integrated by separation of
variables, and an analytical expression derived for the vehicle velocity
as a function of time. This function was fitted to the vehicle coast
down velocity versus time records to obtain the coefficients a.., a., and
a_. A detailed discussion of the test procedures and the data analysis
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is given in the EPA technical support report "Light-Duty Vehicle Road
Load Determination" (1). It should be noted that two vehicle tests
included in the previous report have been deleted from this analysis.
Plotting the force versus speed curves for these tests showed unreal-
istic behavior at low speeds. The original data sheets for these ve-
hicles disclosed that one test had been considered void by the test
personnel and that the vehicle had been retested. The retest value is
presented in this report. In the case of the second deletion, there was
a notation on the data sheet that the track direction had been incor-
rectly coded for one low speed coast down. Because of the slight track
grade this could have a very significant effect in the low speed regime,
while having a minimal effect on the force at 50 mph. In the case of
the retested vehicle there was good agreement between both test values
at 50 mph. Consequently, including these test results in the early
analysis had an insignificant effect on the results which only consi-
dered the force at 50 mph.
Analogous to the acceleration coefficients a-, a.. , a» a set of
force coefficients, fQ, f.. and f« may be obtained by multiplying each
'a' coefficient by the total vehicle effective mass, M, as indicated by
equation 4. The force on the vehicle in terms of the 'f' coefficients
and as a function of velocity is:
F - £Q + fxv + f2v2 (6)
where:
ffl = MaQ, etc.
The force of equation 6 is the total road load force acting on the
vehicle, including drive train and drive tire losses. When the vehicle
is placed on a dynamometer the vehicle must overcome these losses before
power is transmitted to the dynamometer, therefore the drive train and
drive tire losses must be subtracted to obtain an appropriate dynamo-
meter power absorption. The tire and drive train losses were measured
on a large roll electric dynamometer. From these measurements, estimates
of the tire and drive train losses for a Clayton dynamometer were calcu-
lated. These calculations required the common assumption that, in the
case of radial ply tires, the two vehicle drive tires dissipate as much
power on the dynamometer as all four tires dissipate on a flat surface.
With this assumption, the coefficients for the appropriate dynamometer
power absorption to simulate the road experience of a vehicle with
radial ply tires can be calculated. The radial ply tire case was chosen
since radial ply tires represent over 75% of original equipment tires.
These coefficients are presented for the test fleet of vehicles in Table
2 of Appendix B. A detailed discussion of the assumptions and calcula-
tions are given in the EPA technical support report "Prediction of
Dynamometer Power Absorption to Simulate Light-Duty Vehicle Road Load"
(2).
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C. Comparison of the Dynamometer Curve and the Vehicle Curves
In order to compare the appropriate dynamometer force versus speed
curves for the various vehicles, all curves were plotted in Figure 2.
This figure demonstrates the wide diversity of the appropriate dyna-
mometer force versus speed curves for a diverse class of vehicles.
Since the dynamometer curves in Figure 1 are for a single absorber
setting, they do not consider the variation in the dynamometer curve
shape for different power absorber settings. To make this comparison a
dynamometer curve, forced to match the vehicle curve at 50 mph, was
computed for each vehicle. The previous analysis identified the v term
as the term dependent on the dynamometer power absorber setting. There-
fore, the dynamometer curve was matched to the vehicle curve at 50 mph
by adjusting the coefficient of this term.
It should be noted that this match would occur in practice only if
the system used by EPA to predict the dynamometer power absorber setting
was extremely accurate for the particular vehicle, or if an alternate
technique was used to determine the power absorber setting. In many
instances there would be an additional error introduced by inappropriate
adjustment at the 50 mph point.
The dynamometer force versus speed curve, matched to the calculated
appropriate dynamometer adjustment curve at 50 mph, was plotted for each
vehicle. These plots are given in Appendix C. Persual of these graphs
show that in the majority of cases the dynamometer curve appears to
either approximately match the vehicle curve or to be lower than the
vehicle curve at low speeds. In few instances is the dynamometer curve
higher than the vehicle curve. Therefore, there appears to be a sys-
tematic tendency for the dynamometer curve to fall below the vehicle
curve at low speeds.
In order to test if the dynamometer curves were systematically
lower than the vehicle curves, the mean of each set, at 20 mph, was
computed. A "t test" of the difference between the means indicated that
the dynamometer curves were systematically lower than the vehicle curves
with greater than 99 percent confidence. The difference between the
means of the dynamometer curves and the vehicle curves, at 20 mph, was
approximately 5 pounds force. This difference is approximately 20
percent of the mean vehicle force at that speed. This difference is
also 20 percent of the power at this speed however, it is only 0.3
horsepower at 20 mph.
The mean speed of the EPA urban cycle is approximately 20 mph,
therefore, this difference could have a significant effect on the
vehicle fuel economy and exhaust emissions on this cycle. Consequently,
possible sources for this difference were investigated. The vehicle
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o
o
CO<
LU
O
DC
Q4-
VEHICLE
CURVES
10.
20. 30.
SPEED (MPH)
40.
50.
60.
FIGURE 2
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—9—
curves of this report were calculated from the total measured road
experience of the vehicle, by subtracting estimates of the tire and
drive train losses which would occur when the vehicle is operated on a
twin-roll dynamometer. The drive tire losses on the twin-roll dynamo-
meter were estimated to be the sum of the dissipative losses of both the
driving tire and non-driving tires as measured on a large single-roll
dynamometer after correction to flat surface conditions. This is the
common "two on the rolls equals four on the road" assumption. To the
extent that the above assumption and the measurements are correct, the
vehicle curve represents the aerodynamic drag of the vehicle plus the
non-driving wheel bearing and brake drag forces.
The observed differences between the vehicle and dynamometer curves
could occur erroneously if: the road measurements of the vehicle yielded
inappropriately large values, especially in the low speed regions; or if
the measured tire losses were inappropriately low, such that insufficient
force was subtracted from the vehicle road measurements.
1. The Road Measurements
It was hypothesized that ambient condition effects might cause
inappropriately large forces to be computed from the road measurements.
For example, the presence of wind will give rise to higher observed low
speed forces if not adequately treated by the data analysis. To test if
the data analysis did adequately treat ambient conditions, the presence .
of possible relationships between the difference of the vehicle-dynamo-
meter curves and the ambient conditions were tested. "Chi square" tests
showed the difference between the curves to be strongly independent of
both ambient wind conditions and ambient temperature. No correlation
between the difference variable and either ambient condition was obser-
ved. It was therefore concluded that no evidence existed to support an
ambient condition effect.
2. Tire Dissipation Losses
The observed vehicle-dynamometer curve differences could occur if
the tire dissipation forces were systematically low. There are several
reasons this could occur. The tire measurements were obtained by
motoring the vehicle on the dynamometer. The wheels were motored both
with the full vehicle weight on the dynamometer and with the tires "just
contacting" the dynamometer roll. The difference was taken to be the
tire dissipation. Even in the "just contacting" configuration some
force must be acting across the tire-dynamometer interface since the
dynamometer is able to turn the vehicle wheel. This force must give
rise to some dissipation in the vehicle tire. This would be subtracted
from the dissipation measured with the full vehicle weight on the dyna-
mometer rolls. Therefore, there exists a systematic tendency to under-
estimate the tire losses.
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The differences among the vehicle curves, as compared to the dyna-
mometer curve, could be caused by difference in the non-driving wheel
bearing and brake drag among the vehicles. In this case variations in
the values of the vehicle residual friction would be correctly observed.
3. Non-Driving Wheel Bearing and Brake Drag
The relationship between the vehicle-dynamometer curve differences
and measurements of the non-driving wheel bearing and brake drag were
investigated. The scatter plot of these parameters, Figure 3, indicates
some general trends between the variables. A linear regression line,
also shown on the figure, has the expected positive slope characteris-
tic. However, as expected from the scatter plots, the multiple corre-
lation coefficients were low. Thus, the regression should only be
considered as supporting evidence of a weak relationship between the
variables.
The weakness of the observed relation between the differences of
the vehicle and dynamometer curves possibly occurred because of the
vehicle use between these measurements. The track measurements were
conducted at the Transportation Research Center of Ohio and the vehicles
were then driven about 150 miles to the EPA Laboratory where the dynamo-
meter measurements were conducted. The vehicle brake drag is probably
dependent on recent brake use and might change during this interval.
Even if the vehicle brake drag were dependent on recent vehicle use
it would probably be related to the vehicle weight. This indirect
relationship would occur because heavier vehicles would have larger
brakes capable of exerting larger forces, when or if, brake drag occurred.
The relationship between the vehicle-dynamometer curve differences
and the vehicle weight was statistically investigated. "Chi square"
tests for the independence of the vehicle-dynamometer differences versus
the vehicle weight rejects the hypothesis that these variabiles are
independent at the 90 percent confidence level. A linear regression
between these variables demonstrated the expected increase in vehicle-
dynamometer curve differences with increasing vehicle weight. The data,
and the regression line are plotted in Figure 4. As would be expected
from the data scatter the correlation coefficient of the regression was
quite low. Again the regression only supports the evidence of an inter-
relationship between these variables, and should not be expected to
yield accurate predictions of the vehicle brake drag.
Stepwise forward and backward multiple regressions of the vehicle-
dynamometer curve differences using both the measured drag and the
vehicle weight were computed. By both methods, drag entered in the
regression and weight was left out. That is, drag statistically contri-
butes more to the equation than does weight. This is to be expected
since the vehicle weight was only considered to be an indirect predictor
of the brake drag.
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Vehicle-Dynamometer Curve Differences
versus
Measured Non-Driving Wheel Bearing and Brake Drag
DIFF(LBS)
40.000 *
30.000 *
20.000 *
10.000
0.000
*** *
-10.000 *
0.
10.000 20.000 DRAb(LBS)
s.nooo is.oon 25.000
Figure 3
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Vehicle-Dynamometer Curve Differences
versus
Vehicle Weight
DIFF(LBS)
40.000 *
30.000
20.000
10.000
0.000
3«-
» *
»
« «
-10.000 *
1000.0 3000.0 5000.0 ME KiHT(LBS)
2noO.O 4000.0 6000.0
Figure 4
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The dynamometer measurements were primarily intended to determine
the tire rolling resistances. Consequently, the experimental errors
observed when measuring the much smaller wheel bearing and brake drag
forces could be considerable. In addition, if the observed brake drag
is dependent on the recent brake experience, errors could occur in the
dynamometer measurement of the non-driving wheel bearing and brake drag
since these measurements were conducted after considerable dynamometer
warm-up of the vehicle. This warm-up was conducted by motoring the
vehicle with the dynamometer and did not exercise the vehicle brakes.
During the track phase of the vehicle testing, however, the brakes would
probably be exercised during the vehicle turn-around manuvers at the end
of the straight track.
To further verify that the vehicle-vehicle and vehicle-dynamometer
curve differences could be caused by brake drag, more precise measure-
ments of vehicle non-driving wheel bearing and brake drag were conducted
on several vehicles in the EPA parking lot. In these measurements the
force necessary to cause front wheel rotation was measured directly.
Care was taken to attempt to measure the force necessary to maintain
wheel rotation and to minimize the observation of static friction or
"break away" effect.
The measured forces ranges from about 1 pound to about 10 pounds
for the total drag force for both wheels of vehicle non-driving axle.
The lowest force measurements occurred on the vehicle with the highest
mileage, while the highest force measurement occurred on the vehicle
with the lowest mileage. These measurements demonstrate that signi-
ficant differences can exist in vehicle road load forces at low speeds.
Many of the vehicles used in the road load project were low mileage
rental vehicles or vehicles which had been used for certification
testing. Therefore, brake drag measurements were repeated on several
4000 mile certification vehicles. The mean of these force measurements
was 9.7 pounds. This indicates that the observed systematic tendency
for the vehicle curves to be higher than the dynamometer curves in the
low speed region may occur because the dynamometer load in this region
is insufficient to simulate the typical brake drag of a low mileage
vehicle. In addition, this supports the other evidence that the vehi-
cle-dynamometer curve differences are at least partially related to the
vehicle brake drag.
IV. Conclusions
The following aspects were concluded during this study:
1. Variations among the different EPA dynamometers exist and are
statistically significant.
2. Differences exist between the appropriate dynamometer road load
simulation curves for different vehicles. The observed variations
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among the vehicles are greater than the dynamometer variations.
3. The current EPA dynamometers appear to supply insufficient load at
low speeds to correctly simulate the average vehicle road experi-
ence. This conclusion is, however, very dependent on the tire-
twin roll interaction; i.e., the assumption that two tires dissi-
pate as much energy on the dynamometer as four tire dissipate on
the road.
A. Variations Among EPA Dynamometers.
This study observed a maximum variation of + 5 pounds force in the
dynamometer loads at 50 mph. At 50 mph, this is equivalent to approxi-
mately +0.7 horsepower. While this may seem relatively small it is
approximately + 6%. This may have a potential fuel economy variation of
+ 1% on the urban cycle and + 2% on the highway cycle. On a 30 mpg car
the "dynamometer lottery" could win 1.2 mpg on the highway test in a
best to worst dynamometer variation.
B. Vehicle Variations.
The variations among the vehicles are, of course, more pronounced
than the variations among the dynamometers. The variations at 50 mph
can be adequately treated with the current dynamometers, however the low
speed characteristics of the dynamometer are strongly influenced by the
dynamometer residual friction and are not subject to adjustment.
C. Vehicle - Dynamometer Simulation Variances
The data of this report indicate that the current EPA dynamometers
cannot be expected to exactly simulate the road experience of all
vehicles throughout the vehicle speed range. The current dynamometers
appear to demand insufficient power to simulate the average vehicle
during the low speed operation. This conclusion is somewhat tentative
since it is quite dependent on any assumptions about tire power dissi-
pation on the twin-roll dynamometer.
The conclusion that the dynamometer tends to under load vehicles at
low speeds is supported by analysis of data submitted by GM (3). The
submitted data were coast down measurements conducted on both the road
and on the dynamometer for nine vehicles. The purpose of the submission
was to show that the current Federal Register table was approximately
correct for typical light-duty vehicles, but that wide variations could
occur for atypical vehicles. Seven of the nine vehicles were typical
conventional sedans in which the road and dynamometer data at 50 mph
were in good agreement. For these vehicles the dynamometer and road
forces were normalized to the force at 50 mph. For all seven conven-
tional sedans the normalized dynamometer force in the low speed regime
was less than the normalized road force.
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The recent change to the automatic mode of the dynamometer power
adjustment may have caused a slight reduction of the dynamometer load at
low speed. This effect would be quite marginal since the real question
is the low speed tire characteristics and the residual friction of the
dynamometer. These parameters are not affected by the mode of dynamo-
meter adjustment. The recently announced intention of the Clayton
Manufacturing Company to -substitute bearings with lower friction in new
and replacement installations may have a greater effect, since this does
influence the dynamometer residual friction.
The fuel economy effect of low speed dynamometer loading errors
would, of course, be predominantly observed on the urban driving cycle
where the average speed is approximately 20 mph.
A current EPA contract with Southwest Research Institute is inves-
tigating the fuel economy effects associated with changes in the low
speed dynamometer characteristics. Preliminary results from this con-
tract indicate that a 10% change in dynamometer load at 35 mph will
result in a 2% change in the vehicle fuel economy measured on the EPA
urban cycle (4). The observed systematic dynamometer underloading
is approximately 12% at 35 mph; therfore, a two to three percent effect
in the vehicle fuel economy on the urban cycle may be assocaited with
this vehicle-dynamometer difference.
V. Recommendations
It is recommended that the following areas receive continued or
further investigation:
1. The tire-dynamometer rolls interaction;
2. Dynamometer calibration and adjustment;
3. The fuel economy effects of variations in low speed
dynamometer characteristics.
These areas are recommended for attention since they appear to be
the greatest sources of current or potential error. It is further re-
commended that initial investigations in these areas be theoretical in
nature, since it is believed that sufficient data currently exists to
allow relatively easy computation of the approximate magnitude of these
effects.
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References
1. G.D. Thompson, EPA Technical Support Report for Regulatory Action,
"Light-Duty Vehicle Road Load Determination", December 1976.
2. G.D. Thompson, EPA Technical Support Report for Regulatory Action,
"Prediction of Dynamometer Power Absorption to Simulate Light-Duty
Vehicle Road Load", April 1977.
3. J.P. DeKany, EPA memorandum, "Electric Chassis Dynamometers for
Exhaust Emission (FTP) Testing", May 19, 1977.
4. J.D. Murrel, EPA discussions.
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APPENDIX A
Dynamometer Data
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TABLE 1 - DYNAMOMETER 1
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
59.65
56.40
53.45
50.70
48.15
45.85
43.75
41.75
39.95
38.25
36.70
35.30
33.90
32.55
31.35
30.30
29.25
28.25
27.30
26.35
25.50
24.70
23.90
23.15
22.45
21.75
21.10
20.45
19.90
19.40
18.75
18.15
17.65
17.15
16.65
16.20
15.75
15.25
14.85
14.45
14.00
13.55
13.10
12.80
12.45
12.05
11.75
11.40
11.05
10.65
10.15
TOT FORCE
(LB)
123.90
106.48
102.88
92.37
88.79
74.81
74.73
67.69
60.66
60.60
50.06
50.02
49.98
46.44
39.39
35.85
39.34
32.28
35.78
32.24
28.70
28.69
28.67
25.13
25.12
25.10
21.56
25.08
14.43
21.53
25.04
17.97
17.96
17.96
17.95
14.40
17.93
17.93
10.82
17.91
14.37
17.89
14.36
7.23
17.86
10.80
10.79
14.32
10.79
17.80
17.78
IND FORCE
(LB)
100.81
91.34
82.52
74.77
68.07
62.27
57.04
52.41
48.12
43.97
40.67
37.59
34.72
32.28
29.75
27.54
25.70
24.12
22.30
21.14
20.11
18.79
17.49
16.33
15.26
14.30
13.62
12.87
12.25
11.47
10.73
10.19
9.83
9.47
8.99
8.54
8.16
7.68
7.13
6.73
6.51
6.13
5.80
5.48
5.06
4.75
4.39
4.25
4.26
4.11
3.87
FRIC FORCE
(LB)
23.09
15.15
20.36
17.60
20.72
12.54
17.69
15.29
12.53
16.63
9.39
12.43
15.26
14.16
9.64
8.31
13.64
8.16
13.49
11.11
8.60
9.89
11.18
8.80
9.86
10.80
7.94
12.21
2.18
10.06
14.31
7.78
8.14
8.49
8.96
5.86
9.78
10.24
3.69
11.18
7.86
11.76
8.56
1.75
12.80
6.05
6.41
10.08
6.52
13.69
13.91
-------
TABLE 2 - DYNAMOMETER 2
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
59.80
56.90
54.25
51.70
49.40
47.3.0
45.35
43.50
41.80
40.20
38.70
37.35
36.00
34.70
33.55
32.40
31.30
30.35
29.40
28.45
27.55
26.70
25.90
25.15
24.45
23.75
23.10
22.45
21.75
21.15
20.60
20.05
19.50
18.95
18.40
17.60
16.95
16.30
15.55
15.15
14.85
14.45
14.05
13.65
13.25
12.95
12.60
12.25
12.00
11.70
11.30
11.00
10.70
10.35
10.05
9.85
TOT FORCE
(LB)
113.57
92.62
96.00
85.47
78.42
71.37
67.81
64.26
57.21
57.16
50.11
46.56
50.04
42.98
39.44
42.93
35.87
32.32
35.83
32.28
32.27
28.72
28.71
25.16
25.15
25.14
21.58
25.12
25.10
18.01
21.55
18.00
21.53
17.98
21.51
35.43
10.84
35.35
17.93
10.82
10.82
17.91
10.82
17.89
10.81
10.81
14.35
10.80
7.23
14.33
14.32
7.22
14.31
10.78
10.77
3.63
IND FORCE
(LB)
92.85
84.26
76.00
69.41
63.72
58.37
53.55
49.33
45.28
41.58
38.82
36.37
33.94
31.76
29.78
27.72
26.01
24.50
23.15
21.99
20.80
19.76
18.80
17.77
16.58
15.74
15.06
14.31
13.71
13.06
12.31
11.74
11.12
10.67
10.16
9.35
8.93
8.06
7.45
7.25
7.01
6.73
6.53
6.37
6.06
5.58
5.32
5.10
4.88
4.72
4.72
4.64
4.48
4.50
4.50
4.42
FRIC FORCE
(LB)
20.72
8.37
20.00
16.06
14.70
13.00
14.26
14.93
11.93
15.58
11.29
10.20
16.10
11.22
9.65
15.21
9.86
7.82
12.68
10.29
11.47
8.96
9.90
7.39
8.57
9.40
6.53
10.81
11.39
4.95
9.24
6.25
10.41
7.31
11.35
26.08
1.91
27.30
10.49
3.57
3.81
11.18
4.28
11.53
4.75
5.23
9.03
5.70
2.34
9.61
9.60
2.58
9.83
6.28
6.28
-0.79
-------
TABLE 3 - DYNAMOMETER 3
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
60.20
56.95
54.10
51.35
48.90
46.65
44.45
42.55
40.80
39.10
37.55
36.10
34.75
33.45
32.25
31.20
30.20
29.15
28.15
27.25
26.35
25.50
24.75
24.10
23.05
22.05
21.40
20.65
20.15
19.65
19.10
18.60
18.10
17.65
17.20
16.70
16.20
15.85
15.45
15.00
14.60
14.20
13.80
13.40
13.05
12.75
12.45
12.15
11.85
11.50
11.15
10.90
10.60
10.25
10.05
9.85
TOT FORCE
(LB)
127.37
103.05
99.46
95.86
78.40
81.79
74.76
60.73
64.17
57.13
53.59
50.04
46.50
46.47
39.41
35.86
35.85
39.34
32.28
32.26
32.24
28.70
25.15
21.59
52.94
18.02
28.62
25.08
10.85
25.06
14.42
21.52
14.42
17.96
14.41
21.48
14.40
10.83
17.93
14.38
14.38
14.37
14.37
14.36
10.81
10.80
10.80
10.80
10.80
14.33
10.79
7.22
14.31
10.77
3.63
10.77
IND FORCE
(LB)
103.36
92.27
83.19
74.86
67.93
61.48
55.53
51.01
46.68
42.98
39.35
35.72
32.67
30.29
28.00
25.66
23.98
22.29
20.57
19.14
17.60
16.09
15.04
14.24
12.48
11.16
10.26
9.68
9.30
8.62
8.08
7.57
7.24
6.99
6.65
6.02
5.46
5.12
4.73
4.39
4.15
3.79
3.32
2.96
2.73
2.61
2.38
2.02
1.90
1.77
1.54
1.31
1.06
0.95
0.84
0.71
FRIC FORCE
(LB)
24.02
10.78
16.26
21.00
10.47
20.31
19.22
9.72
17.50
14.15
14.24
14.33
13.83
16.18
11.41
10.21
11.86
17.05
11.71
13.12
14.64
12.61
10.11
7.36
40.46
6.85
18.36
15.40
1.55
16.44
6.34
13.95
7.17
10.98
7.76
15.46
8.94
5.71
13.20
10.00
10.23
10.58
11.05
11.40
8.08
8.19
8.43
8.78
8.90
12.55
9.24
5.91
13.24
9.. 83
2.79
10.06
-------
TABLE 4 - DYNAMOMETER 4
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
59.85
56.80
54.00
51.40
49.00
46.90
44.90
43.00
41.25
39.65
38.15
36.75
35.45
34.25
33.05
31.90
30.85
29.85
28.95
28.10
27.25
26.35
25.50
24.75
24.10
23.35
22.55
22.00
21.45
20.75
20.20
19.70
19.15
18.60
18.10
17.60
17.05
16.60
16.20
15.70
15.30
15.00
14.60
14.25
13.90
13.50
13.10
12.80
12.50
12.10
11.75
11.40
11.05
10.75
10.40
10.10
9.90
9.70
TOT FORCE
(LB)
110.11
106.50
92.51
92.40
78.41
71.36
71.29
64.24
60.70
53.64
53.60
46.55
46.52
39.45
46.46
35.88
39.38
32.31
32.29
28.74
32.26
32.24
28.70
25.15
21.59
32.18
25.12
14.44
25.10
25.08
14.43
21.54
17.98
21.52
14.42
21.50
17.96
14.40
14.40
21.45
7.24
14.38
14.38
10.82
14.37
14.36
14.36
7.23
14.35
14.34
10.79
14.32
10.79
10.78
14.30
7.22
7.21
7.21
IND FORCE
(LB)
100.58
89.25
81.22
73.17
66.29
61.18
56.19
51.32
47.32
44.33
40.78
37.30
34.91
32.75
30.63
28.98
27.37
26.27
24.14
22.49
21.62
20.43
19.51
18.71
17.68
16.38
15.38
14.52
13.82
13.23
12.60
11.95
11.50
11.11
10.45
9.80
9.59
9.26
8.90
8.37
7.99
7.70
7.46
7.25
6.98
6.75
6.62
6.55
6.03
5.55
5.34
5.19
5.09
4.86
4.71
4.64
4.40
4.28
FRIG FORCE
(LB)
9.53
17.26
11.30
19.23
12.12
10.18
15.10
12.92
13.37
9.31
12.82
9.24
11.60
6.70
15.83
6.90
12.01
6.04
8.15
6.25
10.64
11.81
9.19
6.44
3.92
15.79
9.74
-0.08
11.27
11.85
1.83
9.59
6.49
10.41
3.96
11.70
8.37
5.15
5.50
13.08
-0.75
6.68
6.92
3.57
7.38
7.62
7.73
0.68
8.31
8.79
5.46
9.13
5.69
5.92
9.59
2.58
2.82
2.94
-------
TABLE 5 - DYNAMOMETER 5
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
59.40
56.15
53.30
50.75
48.20
45.90
43.80
41.80
40.10
38.55
37.10
35.65
34.30
33.10
31.95
30.85
29.85
28.95
28.05
27.15
26.30
25.50
24.75
24.05
23.35
22.70
22.10
21.40
20.70
20.20
19.70
19.15
18.60
18.05
17.60
17.15
16.65
16.20
15.75
15.30
14.95
14.60
14.15
13.75
13.40
13.00
12.65
12.30
11.95
11.60
11.25
10.95
10.65
10.30
10.05
9.85
TOT FORCE
(LB)
120.45
109.93
92.49
88.91
92.25
71.32
78.20
64.21
57.16
53.62
50.07
53.53
42.97
42.95
39.40
39.38
32.31
32.29
32.28
32.26
28.71
28.70
25.15
25.14
25.13
21.58
21.57
28.62
21.55
14.43
21.54
17.98
21.52
17.97
14.41
17.96
17.95
14.40
17.93
14.39
10.82
14.38
17.90
10.81
14.36
14.35
10.80
14.34
10.80
14.33
10.79
10.78
10.78
14.30
3.63
10.77
IND FORCE
(LB)
105.57
93.74
84.47
76.16
67.90
61.75
55.82
51.05
47.12
43.26
39.62
36.25
33.18
30.44
28.46
26.56
24.50
22.59
21.16
19.74
18.22
17.03
15.99
14.92
14.08
13.16
12.20
11.32
10.65
10.11
9.46
9.01
8.39
7.82
7.48
6.99
6.51
6.17
5.79
5.45
5.11
4.74
4.37
4.28
4.14
3.90
3.56
3.19
3.08
2.95
2.84
2.84
2.72
2.48
2.27
2.13
FRIC FORCE
(LB)
14.87
16.19
8.01
12.75
24.35
9.57
22.38
13.16
10.04
10.36
10.45
17.28
9.79
12.50
10.95
12.82
7.81
9.70
11.12
12.52
10.49
11.67
9.16
10.22
11.05
8.42
9.37
17.29
10.90
4.32
12.07
8.97
13.12
10.15
6.93
10.97
11.44
8.23
12.14
8.93
5.71
9.64
13.54
6.54'
10.22
10.45
7.24
11.15
7.71
11.38
7.94
7.94
8.06
11.82
1.36
8.64
-------
TABLE 6 - DYNAMOMETER 6
DYNAMOMETER COAST DOWN DATA
AVG SPEED
(MPH)
59.40
56.30
53.45
50.90
48.40
46.10
44.15
42.30
40.60
38.95
37.45
36.05
34.70
33.45
32.25
31.20
30.25
29.30
28.35
27.45
26.60
25.80
25.10
24.45
23.75
23.10
22.50
21.95
21.30
20.60
20.15
19.75
19.25
18.70
18.20
17.80
17.35
16.95
16.55
16.10
15.75
15.40
15.05
14.75
14.35
13.95
13.65
13.30
13.00
12.75
12.45
12.15
11.90
11.65
11.30
11.00
10.70
10.35
10.10
9.95
TOT FORCE
(LB)
113.55
106.48
95.96
85.44
92.26
71.33
67.78
64.22
57.18
60.62
46.56
53.54
42.98
46.47
39.41
35.86
32.31
35.83
32.28
32.27
28.72
28.71
21.60
25.15
25.14
21.58
21.58
18.01
28.61
21.55
10.85
17.99
17.99
21.52
14.42
14.41
17.96
10.84
17.95
14.40
10.83
14.39
10.82
10.82
17.91
10.82
10.81
14.36
7.23
10.80
10.80
10.80
7.23
10.79
14.32
7.22
14.31
10.78
7.22
3.63
IND FORCE
(LB)
103.12
93.11
83.94
76.56
68.97
62.92
57.30
52.35
48.43
44.10
40.51
37.19
34.72
32.52
30.48
28.14
26.16
24.22
22.35
21.03
19.88
18.57
17.45
16.22
15.15
14.23
13.28
12.59
11.79
11.01
10.49
9.96
9.48
8.98
8.67
8.20
7.58
7.26
6.86
6.52
6.19
5.69
5.35
4.99
4.60
4.40
4.28
4.14
3.93
3.68
3.44
3.32
3.22
2.96
2.72
2.50
2.24
2.01
1.90
1.91
FRIC FORCE
(LB)
10.42
13.37
12.02
8.88
23.30
8.41
10.47
11.87
8.74
16.52
6.06
16.35
8.27
13.95
8.94
7.72
6.16
11.61
9.93
11.23
8.84
10.14
4.16
8.92
9.99
7.35
8.30
5.43
16.82
10.54
0.36
8.03
8.50
12.53
5.75
6.22
10.38
3.58
11.09
7.87
4.64
8.70
5.47
5.83
13.30
6.42
6.54
10.22
3.30
7.12
7.36
7.48
4.01
7.83
11.61
4.72
12.07
8.76
5.31
.1.71
-------
APPENDIX B
Vehicle Data
-------
VEHICLE
IDENTIFICATION
NUMBER
101
201
301
401
502
601
804
901
1001
1102
1201
1301
1401
1501
1601
1702
1802
1901
2102
2203
2301
2401
2502
2602
2706
2802
2906
3011
3102
3212
3304
3402
3505
3613
3908
4014
4102
4202
4402
4507
4607
4701
4801
4903
5103
5203
5303
5403
5503
5603
5601
5701
5802
6002
6102
6202
6302
6402
6502
6702
6802
6909
8101
8401
9101
MODEL
YEAR
1974
1975
1975
1975
1975
1975
1974
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1973
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1975
1976
1975
1975
1975
TABLE 1
TEST FLEET
MANUFACTURER
Chevrolet
Chevrolet
Pontiac
Pontlac
Ford
Oldsmobile
American Motors
Chevrolet
Chevrolet
Ford
Buick
Buick
Buick
Buick
Chevrolet
Ford
Ford
Buick
Mercury
Plymouth
Buick
Buick
Lincoln
Mercury
Toyota
Mercury
Toyota
Saab
Ford
Triumph
American Motors
Ford
Volkswagen
Honda
Mazda
Fiat
Mercury
Ford
Ford
Da t sun
Datsun
Pontiac
Oldsmobile
Dodge
Plymouth
Plymouth
Plymouth
Plymouth
Chrysler
Chrysler
Pontiac
Oldsmobile
Ford
Mercury
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Volvo
Chevrolet
Oldsmobile
Chevrolet
1
MODEL BODY V
NAME STYLE
Impala Sedan
Chevelle Sedan
Firebird Sedan
Ventura Sedan
Pinto Sedan
Cutlass Sedan
Gremlin Sedan
Impala Stationwagon
Vega Sedan
Granada Sedan
Century Sedan
Special Sedan
Skylark Sedan
Apollo Sedan
Monza Sedan
Mustang Mach 1 Sedan
Mustang Sedan
Skyhawk Sedan
Capri II Sedan
Valiant Sedan
LeSabre Sedan
Estate Stationwagon
Continental Sedan
Capri Sedan
Corolla Sedan
Comet Sedan
Celica Sedan
99 Sedan
Mustang Mach 1 Sedan
TR6 Convertible
; Pacer Sedan
Maverick Sedan
Rabbit Sedan
CVCC Sedan
RX-3 Stationwagon
128 Sedan
Montego Sedan
Gran Torino Sedan
LTD Sedan
280Z Sedan
B210 Sedan
Lemans Sedan •"
Cutlass SupremeSedan
Dart Sedan
Valient Custon Sedan
Gran Fury Sedan
Scamp Sedan
Valiant Sedan
New Yorker Sedan
Newport Sedan
Lemans Sedan
Delta 88 Sedan
Granada Sedan
Montego Sedan
LTD Sedan
Torino Sedan
Granada (1) Sedan
LTD Sedan
Torino Stationwagon
Gran Torino Stationwagon
Gran Torino Sedan
264DL Sedan
Corvette Sedan
Toronado Sedan
Corvette(2) Sedan
TEST
JEIGHT
(LBS)
4560
4100
3640
3520
2800
4250
2970
5250
2680
3510
4140
4020
3720
3910
3490
3000
3020
3200
2570
3600
4870
5590
5450
2350
2470
3320
2760
2710
3320
2650
3330
3320
2170
1900
2680
2180
4560
4570
4860
3110
2310
4230
4330
3610
4260
4840
3680
3620
5120
4840
4320
4770
3760
4500
5020
4420
3800
5060
5210
5000
4600
3290
3850
5170
3820
(1) Same vehicle as 5802.
(2) Same vehicle as 8101, however head lamps up.
-------
TABLE 2
TWIN SMALL ROLL DYNAMOMETER POWER ABSORPTION ESTIMATES
FOR VEHICLES WITH RADIAL TIRES
ID
101
201
301
401
502
601
804
901
1001
1102
1201
1301
1401
1501
1601
1702
1802
1901
2102
2203
2301
2401
2502
2602
2706
2802
2906
3011
3102
3212
3304
3402
3505
3613
3908
4014
4102
4202
4402
4507
4607
4701
4801
4903
5103
5203
5303
5403
5503
5601
5603
5701
5802
6002
6102
6202
6302
6402
6502
6702
6802
6909
8101
8401
9101
0.
0.
-0.
0.
0.
0.
-0.
0.
0.
0.
-0.
-0.
-0.
-0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
0.
0.
0.
-0.
0.
-0.
0.
0.
0.
-0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
0.
-0.
-0.
0.
-0.
-0.
0.
0.
-0.
0.
-0.
0.
FO
(NT)
5961E-H)2
1614E+03
2327E+02
8863E+02
8553E+02
1756E+03
4747E+02
1724E+02
4774E+02
3281E+02
4175E+02
1257E+02
1984E+02
1846E+02
7333E+02
1301E+02
3457E+02
7912E+02
4788E+02
1517E+03
7248E+01
3278E402
1963E+03
5375E-H)2
1340E+01
5872E+02
9889E+02
1594E+03
1473E+02
1295E+03
6325E+01
5651E+02
1055E+03
3142E+01
6141E+02
9543E+02
5200E+02
5724E+02
5926E+02
1193E+02
2209E+02
8817E+02
5423E+02
2160E+02
4212E+02
7191E+02
4619E+02
1426E+03
2105E403
8358E+02
2999E+02
2092E+02
2062E+02
5095E+02
4376E+02
3876E+02
6972E+02
6875E+02
1947E+02
4439E+02
1688E+03
4329E+01
1883E+03
2707E+01
7218E+02
Fl
(KG/SEC)
0.
-0.
0.
-0.
-0.
-0.
0.
0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
-0.
-0.
-0.
0.
0.
0.
0.
0.
0.
-0.
-0.
0.
-0.
0.
0.
-0.
0.
-0.
-0.
0.
0.
-0.
0.
0.
-0.
-0.
0.
0.
0.
0.
-0.
-0.
0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
0.
-0.
0.
-0.
0.
0.
1414E+01
1040E+02
8876E+01
4969E+01
5252EH-01
1207E+02
1464E+02
4515E+01
2625E+01
5216E+01
1318E+02
8975E+01
1184E+02
7160E+01
3808E+01
3076E+01
3445E+01
4224E+01
6730E+00
6778E+01
6477E+01
4406E+01
3310E+01
3099E+01
4767E+01
1062E+01
6976E+01
6169E+01
5061E+01
1108E+02
3905E+01
1382E+02
1047E+01
8338E+01
1287E+01
3597E+01
6834E+01
1814E+02
1486E+01
7797E+01
2361E+01
2181E+01
2535E+01
1088E+02
1055E+02
3683E+01
9681E+01
6241E+01
9938E+01
3676E+01
1350E+02
5547E+01
5750E+01
9232E+01
1612E+02
1294E+02
3356E+01
1239E+02
6926E+01
2241E+01
1115E+02
9895E+01
1099E+02
5436E+01
3061E+01
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
F2
(KG/M)
5860E+00
9936E+00
2000E+00
6926E+00
7195E+00
9457E+00
1032E+00
6562E+00
4068E+00
4610E+00
3270E+00
3936E+00
2255E+00
3596E+00
4953E+00
4373E+00
4544E+00
5647E+00
5188E+00
7477E+00
5202E+00
6615E+00
5077E+00
3366E+00
3499E+00
4602E+00
6477E+00
6943E+00
3735E+00
7864E+00
3760E+00
1693E+00
5202E+00
2122E+00
6015E+00
6859E+00
4874E+00
1744E+00
6670E+00
2515E+00
3359E+00
6013E+00
7274E+00
1701E+00
2431E+00
4845E+00
2600E+00
7847E+00
8128E+00
4269E+00
2314E+00
4750E+00
4446E+00
3783E+00
2086E+00
2446E+00
7182E+00
3583E+00
5551E+00
7385E+00
9875E+00
3338E+00
7654E+00
5472E+00
4822E+00
0.
0.
0.
0.
0.
0.
0.
3.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
F@50
(NT)
3839E+03
4253E+03
2750E+03
3235E+03
3276E+03
3783E+03
3314E+03
4459E+03
3096E+03
3797E+03
4162E+03
3846E+03
3574E+03
3212E+03
2356E+03
3002E+03
3385E+03
2668E+03
2920E+03
3737E+03
3974E+03
4617E+03
5239E+03
2912E+03
2827E+03
3123E+03
2665E+03
3683E+03
3144E+03
2746E+03
2814E+03
3370E+03
3419E+03
2955E+03
3331E+03
3577E+03
4482E+03
4352E+03
3592E+03
2880E+03
2426E+03
3398E+03
3609E+03
3065E+03
3994E+03
3962E+03
3924E+03
3951E+03
3944E+03
3790E+03
3874E+03
3822E+03
3712E+03
4463E+03
4208E+03
3726E+03
3535E+03
3871E+03
4126E+03
4634E+03
4129E+03
3836E+03
3250E+03
3921E+03
3815E+03
HP@50
(HP)
11
12
8
9
9
11
9
13
9
11
12
11
10
9
7
8
10
7
8
11
11
13
15
8
8
9
7
11
9
8
8
10
10
8
9
10
13
13
10
8
7
10
10
9
11
11
11
11
11
11
11
11
11
13
12
11
10
11
12
13
12
11
9
11
11
.507
.746
.243
.697
.817
.340
.933
.365
.280
.379
.475
.528
.711
.627
.062
.998
.147
.996
.751
.202
.910
.838
.702
.726
.472
.361
.988
.039
.424
.231
.435
.100
.249
.857
.984
.720
.433
.045
.766
.631
.273
.184
.817
.185
.972
.876
.762
.841
.822
.359
.610
.454
.126
.375
.612
.168
.594
.603
.367
.888
.377
.496
.741
.753
.433
-------
APPENDIX C
Vehicle - Dynamometer Comparison Plots
-------
8..
8..
UJ
o
GC
£g
VEHICLE
101
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
8..
o
o.
CO<
LJ
CJ
GC
£s
VEHICLE
201
— VEHICLE
-• DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
8..
o
o
GQ<
LU
CJ
QC
VEHICLE
301
VEHICLE
DTNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
81
81
LU
CJ
CC
VEHICLE
401
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
8..
VEHICLE
502
VEHICLE
DYNflMOMETER
•*•
10.
20. 30. 40.
SPEED (MPH)
so.
eo.
-------
o
cc
VEHICLE
601
— VEHICLE
-• DYNflMOMETER
H I
10.
20. 30. UO.
SPEED (MPH)
50. 60.
-------
§,.
g.
UJ
CJ
oc
Ss
VEHICLE
804
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
SO.
60.
-------
38
d
UJ
C_>
DC
VEHICLE
901
VEHICLE
DYNflMOMETER
I I I I
10.
20. 30.
SPEED (MPH)
HO. 50. 60.
-------
3..
8.
CJ
oc
Bi
VEHICLE
1001
VEHICLE
DYNflMOMETER
10.
20. 30. 10.
SPEED (MPH)
50. 60.
-------
8..
o
QC
2s
VEHICLE
1102
VEHICLE
DTNflMOMETER
10.
20. 30.
SPEED (MPH)
50. 60.
-------
s,.
8 .
o
QC
Bi
VEHICLE
1201
VEHICLE
DTNRMOMETER
10.
20. 30. 40.
SPEED CMPH)
50. 60.
-------
g,
LU
O
GC
VEHICLE
1301
VEHICLE
DYNflMOMETER
—I 1 I—
20. 30. 40.
SPEED (MPH)
i i
10.
SO. 60.
-------
8..
g..
m
538
d
CJ
-------
•
o
8..
o
oc
£s
VEHICLE
1501
VEHICLE
DYNflMOMETER
°b
10.
20. 30.
SPEED (MPH)
40.
so.
60.
-------
8
LU
CJ
OC
Sg
o- •
VEHICLE
1601
VEHICLE
DYNRMOMETER
10.
20. 30. UO.
SPEED (MPH)
so.
-------
8..
o
o
CJ
QC
£s
.
0
VEHICLE
1702
VEHICLE
DYNflMOMETER
to.
20. 30.
SPEED (MPH)
40.
50.
60.
-------
8..
§..
CQOD
LxJ
CJ
oc
£s
0-.
VEHICLE
1802
VEHICLE
DYNRMOMETER
10.
20. 30. 40.
SPEED (MPH)
SO. 60.
-------
•
o
8.
UJ
o
cc
o..
VEHICLE
1901
VEHICLE
DYNflMOMETER
io.
20. 30.
SPEED (MPH)
40.
50.
60.
-------
8,.
C0<
UJ
U
QC
o
sf
VEHICLE
2102
VEHICLE
DYNflMOMETER
•4-
-f-
10.
20. 30.
SPEED (MPH)
140.
50.
60.
-------
.
o
o
CJ
§..
O
QC
o..
VEHICLE
2203
VEHICLE
DYNflMOMETER
'o.
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
O
<\J
QQOO
O
QC
O--
VEHICLE
2301
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
o
™ +
o
o
O
QC
O
Cg"
o
CM
VEHICLE
2401
VEHICLE
DTNflMOMETER
°o
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
8..
o
o
_
QC
O
C8"
o
o
CM
VEHICLE
2502
VEHICLE
DTNflMOMETER
X
x
X
10.
20. 30. >40.
SPEED (MPH)
50. 60.
-------
UJ
CJ
GC
£s
at
VEHICLE
2602
— VEHICLE
-• DTNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
8..
o
o
OC
£8
o-
VEHICLE
2706
VEHICLE.
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
LU
O
QC
o
VEHICLE
2802
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
o
o
CM
O
O
LJ
CJ
CC
o
VEHICLE
2906
VEHICLE
DYNflMOMETER
—« 1 i—
20. 30. UO.
SPEED (MPH)
10.
50.
60.
-------
8..
LaJ
CJ
OC
VEHICLE
3011
VEHICLE
DYNflMOMETER
10.
20. 30, 40.
SPEED (MPH)
50. 60.
-------
8..
LU
O
QC
VEHICLE
3102
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
§..
O
oc
o
VEHICLE
3212
VEHICLE
DTNRMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
§..
CJ
oc
o
VEHICLE
3304
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
o
o
LU
O
OC
VEHICLE
3402
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
o
=J».
VEHICLE
3505
8..
OD<
_
CC
£§
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
VEHICLE
3613
O
O
OQ<
LU
O
OC
O.
VEHICLE
DTNflMOMETER
10.
20. 30. HO.
SPEED (MPH)
50.
60.
-------
VEHICLE
3908
8..
o
o.
C0<
UJ
O
oc
o
VEHICLE
DYNRMOMETER
Eg"
o..
0. 10.
20. 30.
SPEED (MPH)
50. 60.
-------
o
=»
8..
o
o
oo<
CJ
QC
o
VEHICLE
4014
— VEHICLE
-• DTNflMOMETER
10.
20. 30. 110.
SPEED CMPH)
50.
60.
-------
8..
8..
QC
VEHICLE
4102
VEHICLE
DTNRMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
VEHICLE
4202
8..
o
o.
CD'
LU
O
OC
£§•
VEHICLE
DTNflMOMETER
10.
20. 30.
SPEED (MPH)
50. 60.
-------
o
o
-------
O
CM
O
O
LU
CJ
or
o
(V
VEHICLE
4507
VEHICLE
DTNflMOMETER
10.
20. 30.
SPEED (MPH)
40.
50.
60.
-------
8..
o
o
LU
O
CC
Sg
VEHICLE
4607
VEHICLE
DYNflMOMETER
10.
20. 30.
SPEED (MPH)
40.
50.
60.
-------
8..
VEHICLE
4701
— VEHICLE
-• DTNflMOMETER
—i
60.
10.
20. 30. 40.
SPEED (MPH)
50.
-------
8..
<_)
oc
2s
§••
VEHICLE
4801
VEHICLE
DYNflMOMETER
•4-
10.
20. 30. 40.
SPEED (MPH)
50.
00.
-------
8..
LU
CJ
GC
VEHICLE
4903
VEHICLE
DTNflMOMETER
10.
20. 30. 40.
SPEED CMPH)
50.
60.
-------
8..
8..
LU
O
DC
o-.
VEHICLE
5103
VEHICLE
DTNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
UJ
o
GC
04-
VEHICLE
5203
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
81
UJ
(_)
CC
VEHICLE
5303
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
8..
§..
QC
VEHICLE
5403
VEHICLE
DYNflMOMETER
10.
20. 30. UO.
SPEED (MPH)
50. 60.
-------
8..
§..
LU
O
CC
28
o.
VEHICLE
5503
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
•
o
8,.
o
o
VEHICLE
sgl DYNflMOMETER
UJ
o
QC
£g
o..
VEHICLE
5601
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
o
o
UJ
O
cc
VEHICLE
5603
VEHICLE
DYNflMOMETER
—I 1 H-
20. 30. 40.
SPEED (MPH)
10.
50. 60.
-------
o
CM
§..
QQ«
o.
CM
VEHICLE
5701
VEHICLE
DYNRMOMETER
°b
10.
20, 30. HO.
SPEED : (MPH)
50. 60.
-------
o
o
LU
O
CC
£g
I
VEHICLE
DYNflMOMETER
10.
20. 30. «iO.
:. SPEED (MPH)
50. 60.
-------
8..
§.
CQ(
LU
01
VEHICLE
6002
— VEHICLE
-• DYNRMOMETER
10.
20. 30. UO.
SPEED (MPH)
50. 60.
-------
o
o
LU
O
OC
£s
o-.
VEHICLE
6102
VEHICLE
DYNRMOMETER
•4-
-I-
10.
20. 30. 40.
SPEED (HPH)
50. 80.
-------
a..
§..
OC
£s
o
CM
VEHICLE
6202
VEHICLE
DYNflMOMETER
•4-
10.
20. 30. 40.
SPEED (MPH)
SO. 60.
-------
8..
UJ
(_>
GC
VEHICLE
6302
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
8..
o
o
LU
CJ
OC
£s
VEHICLE
6402
VEHICLE
DYNflMOMETER
20. 30.
SPEED (MPH)
40.
50.
-------
8..
UJ
(_)
CC
Es
o
VEHICLE
6502
VEHICLE
DYNflMOMETER
°b
10.
20. 30.
SPEED (MPH)
40.
50.
60.
-------
8..
UJ
o
CC
Eg
.
Q,
VEHICLE
6702
VEHICLE
DYNflMOMETER
0.
10.
20. 30. 40.
SPEED (MPH)
50. 60.
-------
8..
o
cc
VEHICLE
6802
VEHICLE
-• DYNflMOMETER
10.
20. 30.
SPEED (MPH)
50.
60.
-------
8.
LJ
O
CC
VEHICLE
6909
VEHICLE
DYNflMOMETER
°0
10.
20. 30.
SPEED (MPH)
uo. so.
60.
-------
8..
o
oc
Ss
VEHICLE
8101
VEHICLE
DYNRMOMETER
I I
10.
20. 30. UO.
SPEED (MPH)
SO. 60.
-------
LJ
O
OC
VEHICLE
8401
VEHICLE
DYNflMOMETER
10.
20. 30. 40.
SPEED (MPH)
50.
60.
-------
8..
_
cc
£g
VEHICLE
9101
VEHICLE
DYNflMOMETER
10.
20. 30. UO.
SPEED (MPH)
50. 60.
------- |