-------
-9-
The range of the data was approximately 5 percent of the mean values.
In the worst case, at a nominal 10.5 horsepower, the range of the data
was 6 percent of the mean coastdwon time at this power. Again the
coastdown time versus the dynamometer power adjustments are approxima-
tely parallel lines indicating there was a systematic effect between
various dynamometer tests.
D. Ford Fiesta (TRC rental vehicle)
This 1978 Ford Fiesta was a rental vehicle supplied by the Transporta-
tion Research Center of Ohio. The data from this vehicle were collected
in the same manner as were the data from the Ford LTD. These data are
presented in Appendix D. The summary data are presented in Table 4 and
plotted in Figure 4.
These data show greater variations among the dynamometers than have been
observed for any of the previous vehicles. These variations were parti-
cularly severe at the lowest test powers. At these powers, 4.3 and 3.2,
actual dynamometer horsepower the range of the variations were almost 14
percent of the coastdown times. It should be noted that these powers
are, however, lower than currently used for exhaust emission certifica-
tion or fuel economy testing at EPA. The lowest power adjustment pro-
vided by the weight based table was 5.9 Hp for a vehicle of less than
1,125 pounds. The lowest power adjustment which has been accepted as an
alternate dynamometer adjustment has been 5.4 horsepower requested by
Ford for the Fiesta. In the test range above 5.4 horsepower the varia-
tions were approximately 10 percent of the coastdown times. The worst
case variation was 11 percent, which occurred at the nominal actual
power of 5.4 horsepower.
It should also be noted that the variations in the case of the Fiesta
were much more random in nature than the variations with the previous
vehicle. This may indicate greater dynamometer variability in the very
low power absorption regions or may indicate that variations in tire
rolling resistance are more predominant. It is also possible that
slight variations in the position of the drive wheels would have a
greater effect in the case of front wheel drive vehicles than in the
case of rear wheel drive vehicles. Since this positioning could be
readily changed by test driver motion of the vehicle steering wheel,
these effects might appear as random variations.
E. Ford Mercury Marquis (TRC rental vehicle)
This vehicle was also a rental vehicle supplied by the Transportation
Research Center of Ohio. The vehicle test program was conducted in the
same manner as the test program for the Ford LTD and the Ford Fiesta.
The data are presented in Appendix E, summarized in Table 5 and plotted
in Figure 5.
The variations observed in the case of the Mercury Marquis were very
similar to those observed for the Cougar, and the Ford LTD. The average
observed range of coastdown times, maximum minus the minimum time, was
about four percent of the mean coastdown time.
-------
-10-
Table 4
Ford Fiesta (TRC Rental Vehicle)
Nominal Mean Coastdown Times Average Coastdown Range of Dyno
Actual (sec) Time for all Dynos Coastdown Times
Power (Hp) Dyno #1 Dyno #2 Dyno #3 Dyno #4 (seconds) (Min-Max, sec)
9.7
8.6
7.6
6.5
5.4
4.3
3.2
8.
8.
9.
10.
12.
12.
14.
24
89
98
45
48
60
26
8.
8.
9.
10.
11.
11.
12.
39
56
57
20
70
60
97
8.43
9.06
9.22
10.69
11.28
11.95
13.60
8.
9.
10.
11.
11.
13.
14.
71
38
17
02
87
33
89
8.
8.
9.
10.
11.
12.
13.
44
97
73
59
83
37
93
0
0
0
0
1
1
1
.47
.82
.95
.82
.2
.73
.92
-------
-11-
Ford Fiesta (TRC Rental Vehicle)
Mean Vehicle-Dynamometer Coastdown Time
versus
Nominal Actual Dynamometer Absorption Power
o
01
CO
•u
CO
a
o
15 •
14
13
12
11
10
•= Dynamometer 1
D = Dynamometer 2
•fc= Dynamometer 3
f= Dynamometer 4
10
Nominal Actual Power (Hp)
FIGURE 4
-------
-12-
Table 5
Mercury Marquis (TRC Rental Vehicle)
Nominal Mean Coastdown Times Average Coastdown Range of Dyno
Actual (sec) Time for all Dynos Coastdown Times
Power (Hp) Dyno //I Dyno #2 Dyno //3 Dyno #4 (seconds) (Min-Max, sec)
13.0
12.0
11.0
10.0
9.0
8.0
7.0
15.
15.
16.
17.
19.
20.
21.
25
93
93
76
30
17
58
15.42
16.28
16.98
17.98
18.75
20.37
21.73
14.
15.
16.
17.
18.
19.
20.
66
61
22
31
81
49
96
15.
16.
17.
18.
19.
21.
87
61
70
76
81
14
15.
15.
16.
17.
18.
19.
21.
11
92
69
69
91
96
35
0.
0.
0.
0.
0.
0.
0.
76
67
76
67
55
88
62
-------
-13-
Ford Mercury Marquis (TRC Rental Vehicle)
Mean Vehicle-Dynamometer Coastdown Times
versus
Nominal Actual Dynamometer Absorption Power
a
0)
co
4J
CO
n!
O
o
a
«
a)
22
21
20
19 "
18- "
17 ••
16
15
= Dynamometer 1
= Dynamometer 2
= Dynamometer 3
= Dynamometer 4
t I I ".•
9 10 11 12
Nominal Actual Power (Hp)
13
FIGURE 5
-------
-14-
Again, the lines of dynamometer power absorption versus coastdown times
for the different dynamometers are generally parallel. The exception
seems to occur at a monimal power of 9 horsepower, where some conver-
gence of the data occurs.
IV. Analysis
This section is divided into three subsections. The first subsection
analyzes the observed dynamometer variability directly. The second sub-
section investigates the effect this dynamometer variability has on the
acceptance or rejection of requests for alternate dynamometer power
absorption. The third subsection summarizes the previous two.
A. Analysis of Dynamometer Variability
The vehicle-dynamometer coastdown variations observed with the Plymouth,
Cougar, LTD and Marquis were similar. The variations observed with the
Fiesta were greater. These results are summarized in Table 6.
In general, the range of variation for heavy conventional drive vehicles
appears to be about 5 percent. The "worst case" range of variations for
these vehicles was about 6%. These results are increased somewhat by
the data obtained from the Plymouth which had somewhat greater varia-
bility than the data from the other rear wheel drive vehicles. The
greater variability of the Plymouth data probably occurred since this
was the first vehicle tested, and somewhat less care was taken with this
test series.
Table 6
Summary of Dynamometer Variations
(Expressed As Percentage)
Average of the Observed "Worst Case"
Range of Variations Range of Variations
Vehicle [(max - min)/(mean)]100% [(max - min)/(mean)]100%
Plymouth
Cougar
LTD
Fiesta
Marquis
Average for heavy , _ _
conventional drive vehicles
Fiesta 10.0 14.0*
5.9
3.3
4.5
10.0
4.1
7.7
3.9
6.2
14.0*
5.1
* This extreme range of variability occurred at dynamometer power
absorptions lower than any value which has currently been used for
EPA testing.
-------
-15-
It should be noted that for all of the heavy conventional drive vehicles,
the curves of the coastdown times versus the dynamometer power absorption
were approximately parallel. In addition, the dynamometers were usually
ranked in the same order. The sequential dynamometer-to-dynamometer
relationships were not the same for all dynamometers, therefore, there
is no reason to believe that any change in vehicle warm-up or weight
variations could induce this systematic effect. The systematic nature
of the dynamometer ranking strongly indicates that even the small re-
maining dynamometer variations can be reduced by improved calibration
techniques.
In the case of the Fiesta, the variability was much greater than for the
heavy conventional drive vehicles. In addition, the variability appeared
more random in nature. Much of this increased variability, when evalu-
ated as a percentage of the coastdown time, occurred because the coast-
down times were shorter for this vehicle. This explains most of the
increased variability observed at the larger dynamometer power absorp-
tions used with the vehicle. In the very low power absorption ranges,
however, the variations in absolute magnitude of the coastdown times
were greater for this vehicle than for the remaining vehicles. This is
believed to be caused by two effects.
First, this power absorption range is below the normal dynamometer power
absorption range for certification tests and is not used in the dynamo-
meter calibration. Therefore, greater dynamometer variability and
potential error is expected in this region. In addition, small changes
in dynamometer power absorption will have very significant changes in
the coastdown time of the vehicle-dynamometer system.
Secondly, it is possible that this variability could result from random
driver induced variations in the tire-roll alignment for front wheel
drive vehicles. Again, small changes in the power requirements of the
system could have significant effects on the coastdown times because of
the lower total system power absorption.
B. The Effects of Dynamometer Variability with Respect to
Acceptance or Rejection of a Request for an Alternate
Dynamometer Power Absorption
The purpose of this investigation is to recommend a tolerance value for
the allowable variation between the "target" coastdown time interval
supplied by the manufacturer and the time interval obtained from the EPA
vehicle-dynamometer confirmatory test. Tolerance values which have been
suggested are 5, 7 and 10 percent of the EPA coastdown time. The poten-
tial results of each of these values will be investigated in this section.
In the first situation it is hypothesized that a manufacturer submits a
true, correct value, for the dynamometer power absorption for his vehicle.
The number and percentages of the times this request would be challenged
is investigated. The second situation hypothesizes that a manufacturer
conducts the original dynamometer power absorption determination on a
-------
-16-
dynamometer randomly selected from a dynamometer population equivalent
to the EPA dynamometers. The question is again the number of times
this request would be challenged at each of the proposed tolerance
levels when the confirmatory tests were conducted on randomly selected
EPA dynamometers. The third situation is somewhat the opposite of the
first two. In this case it is hypothesized that a manufacturer submits
a dynamometer adjustment request which is inappropriate by approximately
one horsepower. The question is, again, how often this request would be
challenged.
1. The probability that a request for a true, correct value for
the dynamometer adjustment would be rejected because of EPA dynamometer
variability.
For this evaluation it is assumed that each nominal dynamometer adjust-
ment is a true, correct dynamometer adjustment for the mean observed
coastdown time. The question for this case is; if each nominal dyna-
mometer power absorption were requested as the dynamometer adjustment
cooresponding to the mean observed dynamometer coastdown time, how often
would this request be rejected assuming random selection of the EPA
dynamometer for confirmation testing. For example considering the first
set of data from the 1969 Plymouth, Table 1, the question is would a
request for a dynamometer adjustment of 15.5 horsepower submitted with a
dynamometer coastdown time of 12.84 seconds be rejected when confirma-
tory tested on any of the EPA dynamometers.
Since it is proposed that the tolerance be unidirectional the only
rejections would occur when a dynamometer yields a coastdown longer than
the mean value plus the tolerance. Therefore, the sum of the mean
values for the dynamometer coastdowns at each of the nominal dynamometer
adjustments plus each of the proposed tolerances were calculated. The
occasions when any observed dynamometer coastdown times exceeded these
values were recorded. These are the instances when a true, correct mean
value would be rejected in an EPA confirmatory test.
Table 7 summarizes the number of instances, based on all of the observed
data, where such a rejection of the dynamometer request would occur. In
the range of dynamometer power absorptions which have been used at EPA
only one rejection of such a dynamometer request would occur. This re-
jection case was observed for the Ford Fiesta at the 5 percent toler-
ance value.
2. The probability of rejection when a dynamometer power absorp-
tion is determined from a dynamometer randomly selected by a manufac-
turer and confirmatory tested on an EPA dynamometer randomly selected.
This case assumes a manufacturer randomly selects a single dynamometer
to perform the vehicle-dynamometer coastdown part of the recommended
practice for Determination of Vehicle Road Load and submits the results
from that dynamometer. It is further assumed that the population of the
dynamometers are the same for both EPA and the manufacturer. With this
-------
-17-
Table 7
Confirmations and Rejections of Dynamometer
Requests Which are True Correct Values
Tolerance Number of Number of Observed Probability
Value Confirmations Rejections of Rejection+
2.1%
0.7%
0.0%
* Two of the three observed failures were at power absorption
settings lower than have yet been used in EPA certification
or fuel economy testing.
** This failure occurred at a power absorption setting lower than any
power adjustment which has yet been used in EPA certification or
fuel economy testing.
+ The observed probability of rejection is th computed ratio of the
number of rejections to the total number of observation, 145.
5%
7%
10%
142
144
145
3*
1**
0
-------
-18-
assumption it is possible to use the results of the EPA tests to predict
the probability a request for an alternate dynamometer adjustment would
be rejected under these conditons since this is equivalent to the
hypothetical case in which a road load determination would be performed
on one randomly selected EPA dynamometer and then the confirmation test
performed on a second, randomly selected dynamometer.
The test data were examined to ascertain the number of possible combin-
ations which would result in acceptance or rejection at each tolerance
level if a requested dynamometer adjustment were determined on one
randomly selected EPA dyanmometer and then confirmatory tested on a
second EPA dynamometer. For example, the data of the 1969 Plymouth,
Table 1 first line, was examined to see if a request for 15.5 horsepower
submitted with the coastdown of any of the dynamometers 1 through 4
would be rejected if confirmatory tested on any of the dynamometers
1 through 4.
Again, a unidirectional tolerance was assumed so that those vehicles
with conservative dynamometer adjustment requests would not be rejected.
Therefore, in this example if the coastdown time was 12.5 seconds, cor-
responding to 15.5 horsepower on dynamometer 3, this request would be
rejected if confirmatory tested at a 5 percent tolerance value on dyna-
mometers 1 and 2. The request would be accepeted in confirmatory tested
on dynamometers 3 or 4. Likewise, a request for 15.5 horsepower corres-
ponding to 12.36 seconds as obtained from dynamometer 4 would be rejected
if confirmatory tested on dynamometers 1 or 2 at the 5 percent tolerance
level, and accepted on dynamometer 3 and 4. Requests based on dynamo-
meters 1 and 2 would be accepted if confirmatory tested on any dynamometer
at the 5 percent tolerance level. Therefore, for the nominal power of
15.5 for the sixteen possible combinations of dynamometers which could
be used for power absorption and subsequent confirmation, four combina-
tions would result in rejection of the 5 percent tolerance value.
Table 8 summarizes the number of possible combinations which would
result in acceptance or rejection of the submitted request at each of
the three suggested tolerance values. In this instance, considering
only the range of dynamometer adjustments which have yet been used at
EPA rejections were observed in 3.6 and 0.9 percent of the observations
at tolerance levels of 5 and 7 respectively.
3. The probability of accepting inappropriate dynamometer adjust-
ment requests.
The previous sections discussed the possiblity of rejecting a request
for an alternate dynamometer adjustment in the cases when that request
was a true correct value and in the case when any inaccuracies resulted
from random dynamometer variability. Naturally, the probability of
rejection diminishes as the allowable tolerance increases. For this
reason it may appear desireable to adopt a rather large tolerance.
However, a large tolerance also means that EPA will accept data from
vehicles which will have been inappropriately tested. This section
considers the probability that an incorrect dynamometer adjustment
request would be accepted at various tolerance levels.
-------
-19-
Table 8
Confirmations and Rejections of Dynmometer Requests
Assuming Random Selection of both the Test and the Confirmation
Dynamometers
Possible Combinations Possible Combinations Percent Rejected
Resulting in Acceptance Resulting in Rejection Based on Total Observations
36* 5.9%
13** 2.1%
52*** 0.8%
* 8 of the observed 36 failures occured at dynamometer power adjustment
settings lower than any yet used for certification or fuel economy
testing.
** 6 of the observed 13 failures occured at dynamometer power adjustment
settings lower than any yet used for certification or fuel economy
testing.
*** 3 of the observed 5 failures occured at dynamometer power adjustment
settings lower than any yet used for certification or fuel economy
testing.
5%
7%
10%
571
594
602
-------
-20-
In this section it is assumed that a manufacturer submits a correct
dynamometer coast down time, but requests a dynamometer power absorption
which is approximately one horsepower less than the true correct power
for that coast down time. For example, in the case of the 1969 Plymouth,
first line of Table 1, the assumption is that the manufacturer would
submit a coast down time of 12.84 seconds as corresponding to 14.5
horsepower.
Table 9 summarizes the probabilities that such requests would be accepted
because of the dynamometer variability and the tolerance values. At the
10 percent tolerance value there is greater than 90 percent probability
that EPA would accept a dynamometer adjustment which was in error by
approximately one horsepower. This prabability decreases as the toler-
ance value decreases, to 32 percent probability at a 5 percent tolerance
value.
C. Summary
The choice of an acceptable tolerance value must be a compromise between
the possiblity of rejecting a legitimate alternate dynamometer request
versus the risk of accepting inappropriate dynamometer adjustments.
Alternately stated, an undue burden should not be imposed on the manu-
facturers, yet the representativeness of the EPA tests must be maintained.
Table 6 demonstrates the average variability in vehicle-dynamometer
coastdown times is about 4 percent for conventional vehicles and is
somewhat higher, approximately 10 percent for the Ford Fiesta, a very
small front wheel drive vehicle.
Table 7 gives the probability that a submitted true correct mean value
for a dynamometer power absorption request and coastdown time interval
would be rejected because of EPA dynamometer variability. Rejection
under these conditions implies the manufacturer has performed in the
best technically correct manner which can be expected, without supplying
a conservative request, and is rejected because of the variability in
the EPA dynamometers.
Rejection under these conditions is considered inappropriate, therefore,
the 5 percent tolerance criteria is considered inappropriate, even
though this would result in only about 1 percent of the currently obser-
ved test vehicles under these conditions. In the dynamometer power
absorption regions currently used for EPA testing, no rejections of true
mean value requests would occur at either the 7 or 10 percent tolerance
value. '
Table 8 may be considered as the probability that a dynamometer power
absorption request and the associated coastdown time would be rejected
considering the dynamometer variability of both the original test dyna-
mometer and the confirmation dynamometer. This table indicates that, in
the region of dynamometer power absorption currently used for EPA
testing, there is about 1 percent probability of rejection with the
7 percent tolerance value. Furthermore, for conventional vehicles, only
-------
-21-
Table 9
Acceptance or Rejection of Requested Dynamometer Adjustments
Differing by Approximately One Horsepower
From the Correct Value
Tolerance
Value
5%
7%
10%
Number of
Acceptances
40
89
115
Number of
Rejections
85
36
10
Percentage of
Acceptances
32%
71%
92%
-------
-22-
two instances of a rejection were observed, indicating a probability for
rejection of only 0.33 percent. The probability of rejection is of
course, even less with the 10 percent tolerance value.
Table 9 provides the probability that EPA will accept an inappropriate
dynamometer adjustment with each of the tolerances. This table demon-
strates that if a tolerance value of 10 percent is chosen there is more
than 90 percent chance of accepting dynamometer adjustment requests
which are in error by approximately 1.0 horsepower. It is considered
that this is an unacceptable risk for EPA. From the standpoint of test
accuracy a tolerance value of 5 percent is the value which appears most
desireable. Only at this level is the probability of rejecting a re-
quested dynamometer setting which is incorrect by approximately 1.0
horsepower greater than the probability of acceptance.
At the current time a tolerance value of 7 percent is considered most
appropriate. This value provides a minimal probability that EPA will
reject an appropriate dynamometer request. Within the range of cur-
rently used dynamometer adjustments, no instances were observed where a
true mean dynamometer adjustment would be rejected. Within the range of
currently used dynamometer adjustments there is only about 1 percent
probability that a dynamometer adjustment would fail a confirmation
test. The very few questions which may arise can be expected to occur
for very small, probably front wheel drive vehicles. Minor additional
care for these small number of vehicles of this type should not impose a
significant burden on either EPA or the manufacturers. For example, a
manufacturer can eliminate even this small risk by determining a dyna-
mometer adjustment from several dynamometers and requesting the mean
value. It is particularly appropriate that additional care be taken in
assuring the representativeness of the dynamometer test of these vehicles
since the test results from such vehicles are very sensitive to variations
in the dynamometer adjustment.
V. Conclusions
It is concluded that a 7 percent allowable tolerance between the submit-
ted coastdown time and the coastdown time obtained during the EPA confir-
matory test is most appropriate at this time.
It is' also concluded that a 5 percent tolerance would be most desireable
from the standpoint of rejecting inappropriate dynamometer requests.
Several improvements in the dynamometer and in the dynamometer calibra-
tion are currently planned by the Laboratory Branch. These improvements
should increase the dynamometer system accuracy sufficiently that the
tighter, 5 percent tolerance value can be adopted.
VI. Recommendation
It is recommended that the tolerance value of 7 percent be adopted for
the 1979 model year. It is further recommended that a tolerance value
of 5 percent be tentatively proposed for the 1980 model year.
-------
APPENDICIES
-------
APPENDIX A
Table A-l
1969 Plymouth
Dynamometer 1
IWC = 5000 pounds
12/12/77
Nominal Indicated Computed Mean
Actual Dynamometer Actual Coastdown
Power Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) (Hp) Run #1 Run #2 Run #3 (sec)
15.5
14.5
13.5
12.5
11.5
10.5
9.5
12.6
11.6
10.6
9.6
8.7
7.7
6.7
15.52
14.50
13.47
12.44
11.52
10.49
9.46
13.16
13.77
14.46
15.16
15.93
16.85
17.76
13.17
13.78
14.46
15.15
15.90
16.80
17.85
13.12
13.77
14.45
15.20
15.91
16.85
17.89
13.15
13.77
14.46
15.17
15.91
16.83
17.83
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9730
B = -2.5051
-------
Table A-2
1969 Plymouth
Dynamometer 2
IWC = 5000 pounds
12/12/77
Nominal Indicated Computed Mean
Actual Dynamometer Actual Coastdown
Power Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) (Hp) Run #1 Run #2 Run #3 (sec)
15.5
14.5
13.5
12.5
11.5
10.5
9.5
12.3
11.4
10.4
9.4
8.5
7.5
6.6
15.56
14.61
13.57
12.51
11.57
10.52
9.57
13.29
13.95
14.63
15.43
16.24
17.15
17.96
13.36
13.97
14.60
15.50
16.14
16.97
17.77
13.40
13.96
14.70
15.40
16.26
17.03
17.78
13.35
13.96
14.64
15.44
16.21
17.05
17.84
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9526
B = -2.5242
-------
Table A-3
1969 Plymouth
Dynamometer 3
IWC = 5000 pounds
12/12/77
Nominal Indicated Computed Mean
Actual Dynamometer Actual Coastdown
Power Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) (Hp) Run #1 Run #2 Run #3 (sec)
15.5
14.5
13.5
12.5
11.5
10.5
9.5
13.1
12.2
11.2
10.3
9.3
8.3
7.4
15.45
14.52
13.48
12.54
11.50
10.46
9.53
12.45
13.10
13.79
14.44
15.26
16.17
17.12
12.51
13.12
13.78
14.46
15.30
16.24
17.08
12.55
13.15
13.83
14.37
15.32
16.20
17.09
12.50
13.12
13.80
14.42
15.29
16.20
17.10
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9617
B = -1.7620
-------
Table A-4
1969 Plymouth
Dynamometer 4
IWC = 5000 pounds
12/12/77
Nominal Indicated Computed Mean
Actual Dynamometer Actual Coastdown
Power Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) (Hp) Run #1 Run #2 Run #3 (sec)
15.5
14.5
13.5
12.5
11.5
10.5
9.5
12.6
11.6
10.6
9.7
8.7
7.7
6.8
15.53
14.50
13.46
12.53
11.50
10.46
9.53
12.13
13.38
14.15
14.93
15.84
16.56
17.30
12.40
13.36
14.03
14.86
15.82
16.50
17.37
12.56
13.40
14.22
15.01
15.78
16.70
17.39
12.36
13.38
14.13
14.94
15.81
16.59
17.35
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9670
B = -2.4182
-------
APPENDIX B
Table B-l
Ford Cougar
Dynamometer 1
IWC = 5000 pounds
12/13/77
Nominal
Ac tual
Power
(HP)
12.5
9.5
13.5
15.5
11.5
10.5
14.5
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run //I Run #2 Run #3 (sec)
9.6
6.7
10.6
12.6
8.7
7.7
11.6
12.44
9.46
13.47
15.52
11.52
10.49
14.50
15.06
17.78
14.59
13.21
15.94
16.62
14.04
15.07
17.82
14.51
13.21
15.95
16.64
13.91
15.11
17.81
14.55
13.25
15.92
16.74
13.96
15.08
17.80
14.55
13.22
15.94
16.67
13.97
Dynamometer Calibration
INHP = M * ACT + B
M = 0.973
B = -2.5051
Vehicle Warm-Up Started at 2:49
-------
Table B-2
Ford Cougar
Dynamometer 2
IWC = 5000 pounds
12/13/77
Nominal
Ac tual
Power
(HP)
12.5
9.5
13.5
15.5
11.5
10.5
14.5
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run //I Run #2 Run #3 (sec)
9,4
6.6
10.4
12.3
8.5
7.5
11.4
12.44
9.52
13.48
15.46
11.50
10.46
14.53
15.14
17.64
14.53
13.40
16.05
16.91
13.91
15.22
17.67
14.54
13.42
16.05
16.94
13.95
15.23
17.77
14.60
13.45
16.15
17.02
13.99
15.20
17.69
14.56
13.42
16.08
16.96
13.95
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9568
B - -2.5242
Vehicle Warm-Up Started at 12:55
-------
Table B-3
Ford Cougar
Dynamometer 3
IWC = 5000 pounds
12/14/77
Nominal
Actual
Power
(HP)
12.5
9.5
13.5
15.5
11.5
10.5
14.5
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
10.3
7.4
11.2
13.1
9.3
8.3
12.2
12.54
9.53
13.48
15.45
11.50
10.46
14.52
14.59
17.11
14.07
12.90
15.58
16.49
13.55
14.64
17.22
14.03
12.94
15.62
16.55
13.59
14.63
17.19
14.08
12.95
15.66
16.53
13.54
14.62
17.17
14.06
12.93
15.62
16.52
13.56
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9617
B = -1.7620
Vehicle Warm-Up Started at 9:45
-------
Table B-4
Ford Cougar
Dynamometer 4
IWC = 5000 pounds
12/13/77
Nominal
Actual
Power
(HP)
15.5
14.5
13.5
12.5
11.5
10.5
9.5
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
12.6
11.6
10.6
9.7
8.7
7.7
6.8
15.53
14.50
13.46
12.53
11.50
10.46
9.53
12.95
13.64
14.16
14.70
15.72
16.66
17.16
13.00
13.63
14.15
14.73
15.71
16.64
17.06
13.06
13.60
14.17
14.90
15.76
16.67
17.22
13.00
13.64
14.16
14.78
15.73
16.66
17.15
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9670
B = -2.4182
Vehicle Warm-Up Started at 8:50
-------
Table B-5
Ford Cougar
Dynamometer 4 - Repeat Test After Routine Calibration
IWC = 5000 pounds
12/14/77
Nominal
Actual
Power
(HP)
12.5
9.5
13.5
15.5
11.5
10.5
15.0
Indicated . Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run //2 Run #3 (sec)
9.7
6.8
10.6
12.6
8.7
7.7
12.0
12.53
9.53
13.46
15.53
11.50
10.46
14.91
15.03
17.85
14.38
13.09
15.90
16.76
13.59
15.18
17.66
14.40
13.18
15.90
16.88
13.65
15.22
17.72
14.43
13.23
15.93
16.94
13.75
15.14
17.74
14.40
13.17
15.91
16.86
13.66
Dynamometer Calibration
INHP = M * ACT + B
M = 0.967
B = -2.4182
-------
APPENDIX C
Table C-l
Ford LTD (TRC Rental)
Dynamometer 1
IWC = 5000 pounds
12/21/77
Nominal
Actual
Power
(HP)
8.5
7.5
9.5
11.5
10.5
13.5
12.5
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(HpJ (Hp) Run #1 Run #2 Run #3 (sec)
5.7
4.7
6.7
8.7
7.7
10.7
9.7
8.43
7.41
9.46
11.52
10.49
13.57
12.54
20.01
21.12
18.64
16.60
17.61
15.06
15.94
20.02
21.35
18.66
16.63
17.72
15.16
15.97
19.85
21.23
18.61
16.60
17.67
15.13
15.98
19.96
21.23
18.63
16.61
17.67
15.12
15.96
Dynamometer Calibration
INHP = M * ACT + B
M = 0.973
B - -2.5051
Vehicle Warm-Up Started at 2:42
-------
Table C-2
Ford LTD (TRC Rental)
Dynamometer 2
IWC = 5000 pounds
12/21/77
Nominal
Actual
Power
(HP)
8.5
7.5
9.5
11.5
10.5
13.5
12.5
Indicated Computed . Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
5.6
4.6
6.6
8.6
7.6
10.6
9.6
8.48
7.43
9.52
11.60
10.56
13.69
12.64
20.18
21.43
18.83
16.94
17.76
15.31
16.05
20.23
21.52
18.54
16.61
17.80
15.36
16.26
20.25
21.53
18.77
16.68
17.84
15.34
16.22
20.22
21.49
18.71
16.74
17.80
15.34
16.18
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9586
B = -2.5242
Vehicle Warm-Up Started at 10:15
-------
Table C-3
Ford LTD (TRC Rental)
Dynamometer 3
IWC = 5000 pounds
12/20/77
Nominal
Actual
Power
(HP)
8.5
7.5
9.5
12.5
10.5
13.5
11.5
Indicated
Computed
Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
6.4
5.4
7.4
10.4
8.4
11.4
9.4
8.49
7.45
9.53
12.65
10.57
13.69
11.60
19.61
20.49
17.95
15.54
16.60
14.22
16.24
19.68
20.55
18.03
15.52
16.77
14.46
16.23
19.41
20.69
18.16
15.56
16.86
14.56
16.28
19.57
20.58
18.05
15.54
16.74
14.41
16.25
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9617
B = -1.7620
Vehicle Warm-Up Started at 10:55
-------
Table C-4
Ford LTD (TRC Rental)
Dynamometer 4
IWC = 5000 pounds
12/20/77
Nominal Indicated
Actual Dynamometer
Power Power Adjustment
(HP) (HP)
8.5
7.5
9.5
11.5
10.5
13.5
12.5
5.8
4.8
6.8
8.8
7.8
10.8
9.8
Computed Mean
Actual Coastdown
Dynamometer Coastdown Times (sec) Time
(Hp) Run #1 Run #2 Run #3 (sec)
8.49
7.46
9.53
11.60
10.57
13.67
12.63
20.06
21.19
18.47
16.90
18.09
15.16
16.08
20.00
21.32
18.64
16.84
17.77
15.14
16.08
20.50
21.39
18.82
16.91
17.73
15.06
16.01
20.19
21.30
18.64
16.88
17.86
15.12
16.06
Dynamometer Calibration
INHP = M * ACT + B
M = 0.967
B = -2.4182
Vehicle Warm-Up Started at 2:45
-------
APPENDIX D
Table D-l
Ford Fiesta (TRC Rental Vehicle)
Dynamometer 1
IWC = 2000 pounds
12/21/77
Nominal
Ac tual
Power
(HP)
4.3
3.2
5.4
7.6
6.5
9.7
8.6
Indicated
Computed
Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run //3 (sec)
2.6
1.6
3.6
5.6
4.6
7.6
6.6
4.30
3.22
5.39
7.55
6.47
9.72
8.64
12.32
13.88
12.42
9.92
10.35
8.16
8.72
12.56
14.22
12.59
10.02
10.48
8.26
8.97
12.91
14.69
12.43
10.01
10.53
8.31
8.99
12.60
14.26
12.48
9.98
10.45
8.24
8.89
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9223
B = -1.3673
Vehicle Warm-Up Started at 1:15
-------
Table D-2
Ford Fiesta (TRC Rental Vehicle)
Dynamometer 2
IWC = 2000 pounds
12/21/77
Nominal
Actual
Power
(Hp)
4.3
3.2
3.4
7.6
8.6
6.5
9.7
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
2.4
1.4
3.4
5.4 '
6.4
4.4
7.4
4.32
3.24
5.40
7.57
8.65
6.48
9.73
11.25
12.70
11.64
9.43
8.42
9.98
8.25
11.68
13.05
11.72
9.58
8.65
10.19
8.49
11.88
13.16
11.73
9.69
8.60
10.42
8.44
11.60
12.97
11.70
9.57
8.56
10.20
8.39
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9246
B = -1.5956
Vehicle Warm-Up Started at 8:30
-------
Table D-3
Ford Fiesta (TRC Rental Vehicle)
Dynamometer 3
IWC = 2000 pounds
12/20/77
Nominal Indicated Computed Mean
Actual Dynamometer Actual Coastdown
Power Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) (Hp) Run #1 Run #2 Run #3 (sec)
4.3
3.2
5.4
7.6
9.7
6.5
8.6
3.2
2.2
4.2
6.2
8.2
5.2
7.2
4.33
3.25
5.41
7.58
9.74
6.50
8.66
11.62
13.14
11.18
8.96
8.25
10.61
9.09
12.04
13.68
11.25
9.38
8.52
10.72
9.12
12.18
13.98
11.40
9.32
8.51
10.74
8.96
11.95
13.60
11.28
9.22
8.43
10.69
9.06
Dynamometer Calibration
INHP <= M * ACT + B
M = 0.9238
B = -0.8007
Vehicle Warm-Up Started at 1:48
-------
Table D-4
Ford Fiesta (TRC Rental Vehicle)
Dynamometer 4
IWC = 2000 pounds
12/20/77
Nominal
Ac tual
Power
(HP)
4.3
3.2
5.4
7.6
6.5
9.7
8.6
Indicated
Computed
Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run //I Run #2 Run #3 (sec)
2.4
1.4
3.4
5.4
4.4
7.4
6.4
4.26
3.18
5.34
7.50
6.42
9.66
8.58
13.20
14.72
11.80
10.17
11.18
8.57
9.38
13.39
14.95
11.89
10.16
10.98
8.73
9.37
13.41
15.01
11.91
10.18
10.91
8.83
9.38
13.33
14.89
11.87
10.17
11.02
8.71
9.39
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9255
B = -1.5435
Vehicle Warm-Up Started at 8:00
-------
APPENDIX E
Table E-l
Mercury Marquis (TRC Rental Vehicle)
Dynamometer 1
IWC = 5000 pounds
1/3/78
Nominal
Ac tual
Power
(HP)
8.8
10.9
13.0
7.8
9.8
11.9
6.7
Indicated Computed Mean
Dynampmeter Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
6.1
8.1
10.1
5.1
7.1
9.1
4.1
8.84 19.23 19.35 19.31 19.30
10.90 16.86 16.93 16.99 16.93
12.95 15.26 15.28 15.21 15.25
7.82 20.17 20.20 20.15 20.17
9.87 17.76 17.76 17.76 17.76
11.93 15.91 15.91 15.95 15.92
6.79 21.59 21.58 21.58 21.58
Dynamometer Calibration
INHP = M * ACT + B
M - 0.9730
B = -2.5051
Vehicle Warm-Up Started at 3:05
-------
Table E-2
Mercury Marquis (TRC Rental Vehicle)
Dynamometer 2
IWC = 5000 pounds
1/3/78
Nominal
Actual
Power
(Hp)
8.8
10.9
13.0
7.8
9.8
11.9
6.7
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
5.9
7.9
9.9
4.9
6.9
8.9
3.9
8.79
10.87
12.96
7.76
9.83
11.92
6.70
18.74
16.76
17.06
15.41
20.37
18.06
16.24
21.69
18.73
17.03
17.04
15.40
20.37
17.91
16.32
21.72
18.79
16.94
17.06
15.46
20.36
17.98
16.29
21.77
18.75
i
16.98
15.42
20.37
17.98
16.28
21.73
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9586
B = -2.5242
Vehicle Warm-Up Started at 10:45
-------
Table E-3
Mercury Marquis (TRC Rental Vehicle)
Dynamometer 3
IWC = 5000 pounds
12/30/77
Nominal
Ac tual
Power
(Hp)
8.8
10.9
13.0
7.8
• 9.8
11.9
6.7
Indicated Computed Mean
Dynamometer Actual Coastdown
Power Adjustment Dynamometer Coastdown Times (sec) Time
(Hp) (Hp) Run #1 Run #2 Run #3 (sec)
6.7
8.7
10.7
5.7
7.7
9.7
4.7
8.80
10.88
12.96
7.76
9.84
11.92
6.72
18.16
16.24
14.63
19.54
17.22
15.62
20.94
18.21
16.22
14.69
19.42
17.35
15.57
21.00
18.30
16.21
14.66
. 19.52
17.35
15.63
20.94
18.22
16.22
14.66
19.49
17.31
15.61
20.96
Dynamometer Calibration
INHP = M * ACT + B
M = 0.9617
B = -1.7620
Vehicle Warm-Up Started at 1:47
-------