-19-

standard deviation of 6% of rated RPM. The scatter here is greater than
in the 1-2 and 2-3 shift point data, due most likely to shifting occur-
ring when cruise speed has been reached. Since shifting when the desired
cruise speed has been reached lowers the shift point, when compared with
the situation where acceleration is continued in fourth gear, the
results for the 3-4 shift in Table #3 set a lower limit on 3-4 shifting
when continued acceleration is desired. Exactly how much higher the
actual shifting speed for continued acceleration is cannot be determined
without further analysis of the GM data.

A comparison of the vehicle speeds at which the 2-3 shift occurs
with the manufacturer's recommended speed shows that the two speeds are
nearer each other than for the 1-2 shift. The four vehicles with recom-
mended shift speeds of 25 mph were still all shifted later though. The
greatest difference was found with the VW Rabbit which was shifted at
30.9 mph. The Monza was actually shifted sooner than recommended; 28.4
mph vs. a recommended 30 mph. The three three-speeds were shifted at or
near the upper limits of the range of shift speeds recommended for that
gear. This would indicate that at least the upper 5-10 mph of the
recommended range of shift speeds is reasonable and representative for
these three vehicles.

A comparison of the vehicle speeds at the 3-4 shift yields results
similar to the results of the 2-3 shift for the three-speeds. The VW
was shifted right at its certification 40 mph shift speed. The 36.8 mph
shift point for the Monza demonstrates that the 35-50 mph section of the
recommended shifting range is representative. Similarly, at least the
35-40 mph section of the Chevette range and the 30-40 mph section of the
Camaro, are representative of actual driving.

To be able to show that the low ranges of the recommended 2-3 shift
speeds (3-speeds) and 3-4 shift speeds (4-speeds) are representative or
not, a significant portion of the data gathered by GM has been re-
analyzed by EPA personnel to examine the cruise speeds at which people
begin to up-shift their vehicles. In this re-analysis, when a vehicle
entered a cruise after an acceleration, the cruise speed and whether or
not the driver shifted were recorded. A cruise was defined as a period
of time at least three seconds long where all accelerations and decel-
erations were of an absolute magnitude of approximately 0.5 mph per
second or less. An acceleration (deceleration) was defined as any
period of time where speed was increasing (decreasing) (and any time of
constant speed after it) which was not a part of any cruise. In this
way, the entire range of speeds which the manufacturers recommend for
shifting into a cruise could be evaluated.

The results of the analysis are shown in Table #5. The percentage
of the time the vehicle was: shifted into a higher gear upon entering a
cruise from an acceleration is shown for various ranges of cruise speeds.
For example, when the Nova began a cruise between 22.5 and 27.5 mph, the
various drivers only shifted into third gear 36% of the time. At cruises
between 27.5 and 32.5 mph, the drivers shifted 74% of the time. The
vehicle cruising speed at which the vehicle was shifted into a higher


-13-

On-the-Road Shifting Data

Actual data on the shifting of vehicles in traffic is available
from four independent sources, General Motors (GM), Ford, American
Motors (AMC), and the Environmental Protection Agency (EPA) (14, 18,
21). -Each conducted tests to determine when vehicles were shifted
during normal driving conditions. The stimulus for the studies was
automobile noise, but this motive produced no known bias in the results.

The General Motors study was the most comprehensive of the four
that will be presented here. It consisted of nine 1977 vehicles and one
1976 vehicle, three with automatic and seven with standard transmissions
(14, 21). Only the data from the vehicles with standard transmissions
will be discussed here. The vehicles were driven home for the evening
and returned in the morning by GM Technical Center employees. The
vehicles were also driven on business trips during the day. A total of
14,800 shifts were recorded from the seven vehicles. Each vehicle was
driven by 7-13 drivers and the drivers consisted of both men and women.
They ranged in age from 16 to 60 years. All of the drivers knew the
vehicles were instrumented, but only some knew that it was to collect
shifting data. It is the opinion of the GM staff that the data is very
representative of actual driving (20).

A summary of the results of the study is shown in Table 3. In this
analysis of the road data, only those accelerations where the vehicle
started from a stop (or from a very low speed) and continued into high
gear were used. The data was analysed in this way to facilitate its use
in test procedure development with respect to vehicle noise. This type
of analysis is also very useful in comparing the shifting done in actual
driving to the shifting recommended by the manufacturers. Only up-
shifts resulting in continued acceleration are included in the analysis,
except for the shift into high gear. This situation is usually described
in the owner's manuals by a single recommended shift point, which is
easily comparable to the results of the analysis. This situation also
is a typical one in the certification driving cycles.

The mean shift points for each vehicle are shown in terms of four
different quantities: absolute engine RPM, percent of rated RPM, per-
cent of RPM at maximum torque, and vehicle speed. As could be expected
from this range of vehicles, the shift points in absolute RPM and vehicle
speed varied between vehicles. The results in terms of percent of RPM
at maximum torque was also quite scattered. When the results were nor-
malized in terms of percent of rated engine RPM, though, the scatter in
the results for the 1-2 shift and 2-3 shift was reduced significantly.
The mean shift point for the seven vehicles tested was 66% of rated RPM
for the 1-2 shift with a standard deviation of 4% of rated RPM. The
mean shift point for the 2-3 shift was 65% of rated RPM, while the
standard deviation was 4% of rated RPM.

The normalization of the 3-4 shift data in terms of percent of: rated
RPM resulted in a slight increase in scatter over that of vehicle speed.
This is not surprising in this case, since the shift into fourth gear
would be very dependent on traffic conditions and speed limits, as well
as vehicle characteristics. This raises an aspect of the 3-4 shift data


-23-

The results of this analysis appear in Table #6, arranged similarly
to the results shown in Table #5. In all cases except for the 2-3 shift
of the Monza, shifting into a deceleration occurs only at significantly
higher speeds than shifting into a cruise. For example, while the Nova
was being shifted 74% of the time upon entering a 30 mph cruise, the

same Nova was being shifted only 24% of the time
eration at the same speed. For the 2-3 shift of
was reversed. It should be noted, though, that
cruise occurred at a higher engine speed for the
than for any other vehicle, so if the shift into
deceleration could be expected to be similar for
be for this shift of the Monza.

upon entering a decel-
the Monza, the situation
the 50% shift into

2-3 shift of the Monza
cruise and shift into
any vehicle, it would


‘Table

#2c: 3-4 Shift

Vehicles Camaro 1976 Four Vehicle Standard
(1977; GM) Monza Chevette v-8 Rabbit Average Deviation
Average shift

speed from on the 36.8 37.0 33.6 40.8 37.1 2.9
road testing-mph_ (63) (59) (49) (58) (57) (6)
(% of Rated RPM)*

Cruise Speed at

which the vehicle

was shifted half 31 32 31 32 31.5 0.6
time time-mph (53) (51) (45) (46) (49) (4)
(% of rated RPM)

Manufacturer's

Recommended 20-50 25-40 25-40 25-40 42.5 (Upper Limit)
Shift Speed 23.8 (Lower Limit)

* GM's analysis of road data or the 3-4 shift included shifts into-

cruises. Thus, these values are expected to be lower than the upper
limit of the manufacturers recommended shift speed.

<p


-20-

Table #5

Analysis of Shifting into Cruise from an Acceleration
General Motors Data

Vehicle Monza Chevette Nova Camaro Camaro C~10* 1976
(1977) (L-6) (v-8) Pick-up Rabbit
Cruise

Speed Percent of Time Vehicle was In or Shifted Into 3rd Gear Upo

(mph) Entering a Cruise :

12.5-17.5 20 14 0 0
17.5-22.5 44 62 8 10 71 25
22.5-27.5 54 96 36 45 79 0 60
27. 5-32.5 89 98 74 92 91 50 100
32. 5-37.5 95 93 100 56

Cruise Speed where Shifting Occurred 50% of the Time - mph (% Rated RPM)

23 19 27 26 19 30 24
(59) (48) (48) (46) (42) (51) (49)

Minimum of Manuf. Recom. Range of Shift Speeds - mph

15 - 25 25 = 25 19
Cruise
Speed Percent of Time Vehicle was Shifted Into 4th Gear Upon
(mph) Entering a Cruise
22.5-27.5 8 20 43 0
27.5-32.5 47 37 45 35
32.5-37.5 60 79 73 77
37.5-42.5 85 90 75 90

Cruise Speed Where Shifting Occurred 50% of the Time - mph (% Rated RPM)

31 32 : 31 32
(53) (51) (45) (46)

Minimum of Manuf. Recom. Range of Shift Speeds - mph

20 25 25 25

* Only a very limited amount of data was available for re-analysis.


-26-

greater than the average shift speeds listed in Table #3. Thus, it
appears that shifting into a deceleration from an acceleration does not
occur at the same speeds as shifting into a cruise, but occurs at a
speed much closer to the average shifting points (shown in Tables #3 and
#4).

The last aspect of the shifting of cars pertinent to this study is
double shifting. Manufacturers have begun to recommend double shifting
when entering a cruise if the cruise speed is high enough. For example,
it would be the manufacturer's recommendation to double shift the Chev-
ette, Camaro (V-8) and Monza from 2nd to 4th gear upon entering a cruise
at a speed of 25 mph. This particular driving situation should occur
very frequently on the road and a re-analysis of the General Motors data
verified that many 25 mph cruises are entered from 2nd gear. While many
drivers shifted into 3rd in this situation, not one double shifted into
4th gear. During the re-analysis of the GM data, only two double shifts
were found and both were from first to third gear at about 22-25 mph,
which is not recommended by the manufacturer. This result would seem to
state that drivers do not double shift these types of vehicles on the
road and to be representative, double shifting should not occur over the
certification driving cycles.

The question which arises next is: Does it make any difference
when the cars are shifted? The evidence available strongly indicates
that the shifting pattern used over the certification cycle affects both
emissions and fuel economy significantly. A study performed by Peter
Hutchins of the EPA reports on tests of three vehicles over the current
Federal Test Procedure with different shifting patterns (12, 13). The
results are shown in Table #7.

As can be seen, by shifting earlier fuel economy is significantly
increased while carbon monoxide emissions are decreased. The Toyota
showed an 11.7% fuel economy increase and a 4% carbon monoxide decrease
from the use of shift schedule #1 as compared to #4. The VW showed a
11.5% fuel economy increase and a 7% carbon monoxide decrease from the
use of schedule #4 as compared to #5. The Chevette showed a 10.8% in-
crease in fuel economy and a 30.4% decrease in carbon monoxide emission
due simply to the small differences between schedules #2 and #4. The
effect of shift schedules on hydrocarbon and nitrogen oxide emissions
appears to be vheicle specific. Thus, the shifting schedule used during
certification has an effect on emission and fuel economy. If the
shifting schedule is not representative of typical shifting then neither
will the emissions or fuel economy be representative.

It is then necessary to insure that the shifting schedules used
during the certification process are representative of those used on the
road, This can be done most effectively in one of four ways. First,
the EPA could determine typical shifting patterns for various automo-
biles when driven on the road and derive a correlation for shifting
speeds based on vehicle parameters. A quick look at Tables #3 and #4
shows that the shift speed in % of Rated RPM for all the vehicles varies


-22-
Table #6

Analysis of Shifting into a Deceleration from an Acceleration

General Motors Data

Vehicle Monza Chevette Nova Camaro Camaro c-10* 1976
(1977) (L-6) (v-8) Pick-up Rabbit
Peak
Speed Percent of Time Vehicle was in or Shifted into 3rd Gear Upon
(mph) Entering a Deceleration
12.5-17.5 9 17 - - 0
17.5-22.5 63 23 0 8 0 - 0
22,5-27.5 74 47 9 16 20 - 25
27.5-32.5 82 88 24 48 67 - 100
32. 5-37.5 64 27 73 = =
Peak Speed where Shifting Occurred 50% of the Time (mph)

19 25 33 >30 28 27
Peak
Speed Percent of Time Vehicle was Shifted Into 4th Gear Upon
(mph) Entering A Deceleration
22.5-27.5 6 0 0 0
27.5-32.5 12 17 22 16
32.5-37.5 64 10 27 25
37.5-42.5 100 63 = 84

Peak Speed where Shifting Occurred 50% of the Time (mph)
34 39 >35 37

* Insufficient amount of data available to analyze.


-1 7y-
Table #4

Ford, AMC, and EPA Test Results

Tester: Ford EPA (1977's) AMC (1977)
Vehicle: 1976 Pinto VW Rabbit Corolla Chevette Pacer Gremlin
2.3L 1.6L 1.6L 1.4L 258CID 121 CID

4-speed 4-speed 4-speed 4-speed 4-speed _4-speed

Rated RPM 5000 5500 5800 5200 3600 5000

RPM at Max. 3000 3200 3800 3600 2000 2300

Torque

1-2 Shift RPM 3940 3460 3310 3330 2410 3170

% Rated RPM 79.0 63 57 64 67 63

% RPM at 131 108 87 92 120 138

Max. Torque

N/V lst gear 169.3 201 210 208 128 168

RPM/MPH

Actual Speed 23.3 17.3 15.7 16 18.7 18.8

Manufacturer's
Recommended 10 15* 12 10 10-15 10-15
Shift Speed

*VW does not include specific shift points in their owner's manuals. They use the
old Federal shift schedule of 15, 25, and 40 mph for certification testing.


-9-
Current Trends in Manufacturer's Recommended Shift Points

The current test procedure for determining vehicle fuel economy and
emissions, as laid out in the Federal Register, calls for the vehicle to
be shifted as per the manufacturer's recommended shift schedule to the
ultimate purchaser. As long as the shifting schedule in the owner's
manual bears them out, the manufacturers are being allowed to shift
their cars at any speed. The vehicles still must be able to follow the
driving trace within the specified tolerances.

Since the recommended shift points found in the owner's manuals have
such an important role in the way a certification vehicle is driven over
the Federal Test Cycles, it is important to see how these recommendations
have been changing over the years. Prior to 1974, the shift points for
vehicles with manual transmissions were rarely specified. Thus, the
standard 15, 25, and 40 mph shift points were used. For example, the
1971 Dodge Challenger manual gives general recommendations such as
shifting through gears in their numerical order, and shifting from 2nd
to 3rd as soon as practical in order to conserve fuel. Limits for
downshifting are also given, to protect against over-revving the engine.
Very rough up-shift points could be estimated from these downshift
limits. For a three-speed transmission, the shift points would be 10
and 40 mph. For a four-speed transmission, they would be 15~25-50 mph.
The 1968 Chevelle-Camaro-Chevy II manual also recommends shifting up a
gear as soon as possible to increase fuel economy, but gives no vehicle
speeds at which to shift. The 1970 Oldsmobile Cutlass manual does not
even mention this, but does mention, along with Dodge and Chevrolet, to
downshift to 2nd gear at low speeds to improve vehicle performance and
acceleration. The 1973 Volkswagen manual did list recommended speed
ranges for the various gears. From these ranges, it would be possible
to determine the upper and lower limits for the various shift points.
The upper limits would be 16, 34, and 56 mph. The lower limits would be
12, 22 and 31 mph, but would only be practical if all the desired accel-
eration had been completed. Since these limits actually only represent
the two extremes of engine racing and lugging, the point of shifting is
‘still left to the driver. The 1972 AMC owner's manual was the only one
found to recommend specific shifting speeds. AMC recommends that the
driver shift at 18 and 30 mph (three-speed transmissions), and 18, 25,
and 40 mph (four-speed transmissions).

Beginning around 1974, most manufacturer's ‘began to recommend specific
speeds at which to shift their vehicles. Overall, while the rest of the
section dealing with manual transmissions remained the same as prior to
1974, a short paragraph recommending specific shift speeds was now
included. The 1974 AMC manual recommends shifting their three-speed
manuals at 18 and 30 mph (15 and 25 mph with their 3.54:1 axle), and
recommends shifting their four-speed manuals at 18, 25, and 40 mph. The
1975 Ford Pinto manual gives a range of shift speeds; 10-15 mph for a 1-
2 shift, 20-30 mph for a 2-3 shift and over 30 mph for a 3-4 shift. The
1975 Chevrolet Nova manual recommends shifting at 20, 30, and 40 mph.
The 1976 Plymouth (Grand Fury, Fury, Valient, Volare, Duster) manual


-29-

Recommendations

The recommendation of this report is that the above third method be
implemented as soon as possible. The following guidelines appear to be
most useful to assure that vehicles are shifted in a manner representa-
tive of in-use operation:

1)

2)

3)

4)

5)

6)

7)

8)

The 1-2 shift point should be at 66% of rated engine RPM,
possibly allowing up to 5% of rated engine RPM deviation;

The 2-3 shift point should be at 65% of rated engine RPM,
possibly allowing up to a 4% of rated engine RPM deviation;

The 3-4 shift point should be at 57% of rated engine RPM,
possibly allowing up to 6% of rated engine RPM deviation;

The minimum speed at which a vehicle is allowed to upshift
into a cruise should be 49% of rated engine RPM, possibly
allowing up to a 5% of rated RPM deviation;

A cruise in the Federal certification driving cycle should be
defined as a period of time at least three seconds long during
which all accelerations and decelerations (measured over one
second intervals) are of an absolute magnitude of 0.5 per
second or less;

The minimum speed at which a vehicle is allowed to be up-
shifted into a deceleration from an acceleration (no cruise as
defined in #5 in between) should be the same speed as for up-
shifting into an acceleration, which is stated in Guidelines
#1, #2, and #3.

No double up-shifting of vehicles with 3 or 4 speed trans-
missions should be allowed;

If a manufacturer's’ récommendation does not meet the previous
guidelines, he should be allowed the opportunity to submit
data supporting the deviations. If no convincing data are
presented, the above guidelines should be used for shifting
that vehicle during certification testing.


b)

c)

d)

-~6-

Return to the old standard 15-25-40 mph shift schedule; allow
variations only if the manufacturers could demonstrate that the
variations were more representative.

Require all manufacturers to demonstrate that their currently
recommended shift schedules are representative of how their vehicles
are driven on the road, if challenged by the certification staff
(using the guidelines of this report as a basis for challenges);

_ and

Allow certification drivers to shift when they feel appropriate.

The recommendation of this report is that method c) be implemented

as soon as possible. The following guidelines appear to be most. useful
to assure that vehicles are shifted in a manner representative of in-use
operation:

1.

5.

The 1-2 shift point should be at 66% of rated engine RPM, possibly
allowing up to a 5% of rated RPM deviation;

The 2-3 shift point shquld be at 65% of rated engine RPM, possibly
allowing up to a 4% of rated RPM deviation;

The 3-4 shift point should be at 57% of rated engine RPM, possibly
allowing up to a 6% of rated RPM deviations;

The minimum speed at which a vehicle is allowed to up-shift into a
cruise should be at 49% of rated engine RPM, possibly allowing up
to a 5% of rated RPM deviation;

A cruise in the Federal certification driving cycle should be
defined as a period of time at least three seconds long during
which all accelerations and decelerations (over one second inter-
vals) are‘of an absolute magnitude of 0.5 mph per second or less;

The minimum speed at which a vehicle is allowed to up-shift into a
deceleration from an acceleration (no cruise as defined in #5 oc-
curing in between) should be the same speed as for up-shifting into
an acceleration, which is stated in guidelines #1, #2, and #3;

No double shifting of vehicles with 3 or 4 speed transmissions
should be allowed;

If a manufacturer's recommendation does not meet the previous
guidelines, he should be allowed the opportunity to submit data
supporting the deviations. If no convincing data are presented,
the above guidelines should te used for shifting that vehicle
during certification testing.


-5-

The primary conclusions of the report are:

1.

There is no inherent reason to believe that the shift schedules
recommended by the manufacturers in their owner's manuals are
representative of the way people drive on the road;

Many of the shift schedules being currently used during certifi-
cation are not representative of typical driving and are resulting
in higher fuel economy and lower carbon monoxide emissions on cars
tested over the urban driving cycle. In particular, drivers on the
road:

a) Shift into second gear at a significantly higher vehicle speed
than is recommended by the owner's manuals;

b) Shift into cruises only at higher speeds than recommended by
the manufacturers;

c) Do not shift from an acceleration into a deceleration in the
same way they shift from an acceleration into a cruise. Thus, a
distinction between these two occurrences should be made during
certification testing; and

d) Do not double up-shift vehicles with 3 and 4 speed transmissions.

From the data available, it appears that using the manufacturer's
recommended shift schedules as compared to representative in-use
shift patterns results in a 10-15% increase in urban fuel economy
and a 4-30% decrease in carbon monoxide emissions. The effect of
shift schedules on hydrocarbon and nitrogen exoide emissions appears
to be more vehicle specific.

Of the three consumer oriented automotive testing groups surveyed,
none used the shift schedules listed in the owner's manuals to
determine when they shifted their test vehicles;

If the shift schedules used during certification are to be made
representative, a change will be necessary in the current method of
determining shift schedules.

Four possible alternative methods of determining certification shift
schedules are presented:

a)

Develop a detailed correlation which would determine the shift
schedule from vehicle specific parameters (i.e., power to weight
ratio, N/V, etc.); allow variations only if the manufacturers could
demonstrate that the variations were more representative. (This
would most likely require a change in the regulations since EPA
would be specifying the shift schedules for each test vehicle and
would require a significant amount of time in order to collect the
necessary data.)


-18-

percent of rated RPM, the range is narrowed to only 57%-79%. Statis-
tically, the mean shift point of all 13 vehicles is 66% of rated RPM,
and the standard deviation is 5% of rated RPM. It is interesting to
note that many of the unusual factors involved in some of the studies
had little effect on the results. The EPA study was performed on a
track, where traffic conditions were not typical. Yet the VW Rabbit was
shifted only 2% of rated RPM earlier than the Rabbit in the GM study,
while the Chevette was shifted 5% of the rated RPM earlier than in the
GM study. The AMC drivers, who were not used to driving with a standard
transmission, shifted the two vehicles at an average of 65% of rated
RPM, which is nearly at the overall mean of 66%. The Ford study, where
a passenger rode in the car to record shift speeds, resulted in the
largest deviation from the mean, 13% of rated RPM. It would appear from
the EPA and AMC results that it might not be essential to have perfectly
representative traffic patterns or drivers to arrive at reasonable
results.

Also shown in Tables 3 and 4, just below the vehicle speed at
shifting, is the manufacturer's recommended shift speed for that vehicle-
engine-drive train combination (from the owner's manual). A comparison
can be made between the speed the vehicle is shifted on-the-road, and
the shift speed recommended by the manufacturer. Of the 11 vehicles
where this comparison can be made, for the 1-2 shift, in all cases the
manufacturer's recommended speed was less than the actual speed at
shifting. The largest differences occurred for those sub-compacts whose
recommended shift speeds were 10 mph. None of these vehicles were
shifted below 15 mph. The two AMC vehicles, which have suggested shift
speeds of 10-15 mph were both shifted at over 18 mph. The only vehicles
which were shifted at speeds within 20% of the recommended shift speed
were the two vehicles whose recommended shift speeds were 20 mph (Nova
and Camaro (16)).

No recommended shift speeds are shown in the owner's manual for the
VW Rabbit, though a range of possible operating speeds is given for each
gear. The Rabbit is shifted at the previously standard 15-25-40 mph
shift points when tested by the EPA so these speeds have been listed in
Tables #3 and #4. If this 15 mph shift point was compared to the actual
shift points (17.3 and 18,1 mph), again the actual shift speeds are
greater than those used in certification testing by the EPA.

Similar comparisons of the 2-3 and 3-4 shift data shown in Table #3
can also be made, The 2-3 shift point data for the 4~speed vehicles
includes only those accelerations which continued in third gear. The 2-
3 shift data for the three speeds and the 3-4 shift data includes those
accelerations which continued after the shift and also those which did
not continue. To reflect this difference, the recommended shift speed
or range of speeds in the owner's manuals pertinent to the type of shift
occurring have been listed in Table 3.

The 2-3 shift data, like the 1-2 shift data shows a nearly constant
shift point in terms of percent of rated RPM. The mean is 65% of rated
RPM and the standard deviation is 4% of rated RPM. The 3-4 shift data
‘shows a fairly constant shift point around 57% of rated RPM, with a


-8-

aid chart. In Section 86.177-12 Manual Transmissions (11), it states
that; "If the vehicle cannot accelerate at the specified rates, the
vehicle shall be operated with the accelerator pedal fully depressed
until the vehicle speed reaches the speed at which it should be at that
time during the test." ‘In Section 85.075-14 Dynamometer Driving Sched-
ule (10), it states that; "Speed tolerances greater than 2 m.p.h. (such
as occur when shifting manual transmission vehicles) are acceptable
provided they occur for less than two seconds. Speeds lower than those
prescribed may be acceptable provided that the vehicle is operated at
maximum available power during such occurrances." While it might appear
that Section 86.177-12 would allow lower than prescribed speeds in
acceleration modes as long as the accelerator pedal was fully depressed,
Section 85.075-14 would require that the vehicle be performing at maximum
available power. These two requirements differ if the vehicle is being
driven at low engine speed (i.e., relatively high gear for that vehicle
speed), since the power can be increased by downshifting. Thus, a
vehicle falling short of the prescribed speed would be required to
downshift if downshifting would result in increased vehicle acceleration.


-24-

Discussion

The EPA tests vehicles for both gaseous emissions and fuel economy.
The results obtained from these tests are intended to be representative
of the emissions and fuel economies of production vehicles as they are
driven on the road. Much time and effort has been put into the develop-
ment of representative driving cycles and dynamometers which convey
actual driving conditions to the vehicles. Care is taken to insure that
the certification vehicles are representative of the production vehicles
that will follow. In the same way, the shifting patterns used over the
Federal Test Procedure should be representative of those used on the
road by average drivers. .

Currently, the shifting patterns used during vehicle certification
are those recommended by the auto manufacturers in their owner's manuals
(11). Originally this was not the case. The shifting pattern in terms
of vehicle speeds was set by law. In the 1972 model year this was
changed to allow the auto manufacturers flexibility to set different
shifting patterns for their vehicles, since considerable differences
occur between vehicles. It was assumed that any changes made would
still be representative of the way those particular vehicles were driven
on the road. If the recommended shift patterns found in owner's manuals
were actually used by the majority of drivers, this assumption may have
proven correct. At present, though, little data can be brought forth to
show that drivers shift as recommended by their owner's manuals. Thus,
the auto manufacturers can, if they desire, recommend any of a wide
range of shift patterns, with no adverse effects to their customers
satisfaction due to poor vehicle performance.

How do people decide when to shift? The evidence available from
driver's education teachers and manuals suggests people do not learn
when to shift during driver's education. The great majority of auto-
mobiles used to train drivers have automatic transmissions. To suggest
that drivers watch their speedometers and temperature gauges and shift
at a certain speed listed in their owner's manual is just as unlikely.
.A driver is most likely going to shift in such a way that the engine
will operate smoothly and that the vehicle will accelerate at the de-
sired rate. If anyone recommends shifting into second gear at 10 mph
and the vehicle lugs at the desired acceleration rate, the driver is
going to shift later next time.

This is confirmed by four consumer oriented groups who test auto-
mobiles, the Consumer's Union, Road and Track, Motor Trend, and Car and
Driver magazines. None use the recommended shift schedules given in the
owner's manuals in their testing. All four allow their drivers flexibility
in determining when to shift, except for the urban fuel economy testing
done by Car and Driver, who use the old Federal standard 15-25-40 mph
shift schedule. The drivers keep the engine running smoothly and do not
attempt to obtain the optimum fuel economy, but aim for a fuel economy
their readers can obtain with their own cars.


Technical Support Report for Regulatory Action

Shift Schedules for Emissions and
Fuel Economy Testing

by
Richard A. Rykowski

November 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 conclusions 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


-l1-

Shift Points Used by Other Testing Organizations

Four consumer oriented organizations which test automobiles for per-
formance or fuel economy were contacted to discover their method for
determining shift points. The four groups contacted were; Consumer's
Union, Road and Track, Motor Trend, and Car and Driver magazines (7, 6,
4, 5).

Of the four groups contacted, none used the manufacturer's recommended
shift points. Road and Track (6) does their fuel economy testing over
a road course and all their accelerating is done at predetermined rates.
Using a vehicle mounted acgelerometer, their driyers accelerate their
cars af a rate of 7 ft/sec” (0-20 mph), 5 ft/sec” (20-35 mph), and 3
ft/sec’ (35-60 mph). The drivers have experience with the cars they are
testing and shifting is done to keep the engine running smoothly and to
hold to the above acceleration rates. No effort is made to maximize
fuel economy, but rather a reasonable fuel economy, obtainable by their
readers, is their goal.

The Consumer's Union (7) tests automotive vehicles for both ‘fuel economy
and performance. Their goal in fuel economy testing is to shift all
vehicles as near to 15, 25, and 40 mph as possible. When it seems
unreasonable to the driver to shift at these speeds, higher or lower
speeds are used. From their experience, more vehicles need to be shifted
at speeds highér than 15, 25 and 40 mph than need to be shifted at lower
speeds. When testing for vehicle performance, the vehicles are shifted
using three shift schedules. The vehicles are first shifted at the points
where the engine is producing its maximum torque. Then the vehicle is
shifted at speeds just higher and lower than the speeds corresponding to
maximum torque. The best performance resulting from the three shift
schedules is used for that vehicles performance rating.

Motor Trend (4) tests vehicles for both performance and fuel economy.
When testing for performance, their drivers shift at that RPM where
engine torque is at a maximum. When testing for fuel economy, their
drivers shift primarily by feel. The drivers shift as early as possible
while still being able to keep up with traffic and keep the engine
running smoothly.

Car and Driver (5) does their city testing on a chassis dynamometer
using the first 505 seconds of the LA-4 cycle. Over this cycle they
still shift at 15-25-40 mph. They do their highway testing on the road
and their drivers shift when it seems reasonable to them. They are
currently also testing the 15-25-40 mph shift points over their highway
course to determine their applicability.


-10-

includes specific shift speeds fcr its Feather Duster model. These are
15, 25, and 35 mph. The Honda Civic manual recommends shifting at 15,
25, 40, and 45 mph.

The exact year that specific reccommended shift speeds appeared, varied
from manufacturer to manufacturer and even within a manufacturer's
product line. Neither the 1976 Dodge (Monaco, Charger, Coronet, Aspen,
Dart) manual, nor the 1975 Pontiac (LeMans, Grand LeMans, LeMans Sport
Coupe, Grand Am) manual contains any recommended shift speeds, while
their Plymouth and Chevrolet counterparts had begun to do so. This was
the last year that Dodge and Pontiac did not recommend specific shift
speeds to its vehicle owners.

By 1977, this trend to specific recommended shift speeds had expanded to
the point where not only did a mcedel type (or even series of similar
models) have recommended shifting speeds, but each engine-drive train
combination now had its own shift schedule. In addition to the increa-
sed number of shift schedules for each model, many manufacturers have
begun to specify cruising speed ranges. Within these speed ranges, the
vehicle can be driven in a cruising mode (little acceleration). These
manufacturers further specify that once acceleration has ceased, the
vehicle should be shifted into the highest gear allowable at that
cruising speed, independent of the duration of the cruise. This is
recommended even if it means skipping over a gear (i.e., shift from 2nd
to 4th). Examples of owner's manuals showing these latter trends are
the Ford Granada, Pontiac Astre-Sunbird, and Chevrolet Nova manuals.

The latest addition to the complexity of recommended shifting schedules
appeared in 1978. Honda will be recommending (the 1978 owner's manuals
are not available at this date) different shift schedules for a cold
engine and a hot engine. The manual defines an engine as cold, when the
water temperature gauge is reading below normal. Also, the Ford Fiesta
manual contains four different schedules, all of which apply to each
Fiesta sold. Different shift schedules are listed for partial throttle
acceleration, wide open throttle acceleration, normal driving, and
driving for fuel economy.


10.

ll.

12.

13.

14.

15.

16.

17.

18.

-30-
References
American Automobile Assoc. , Sportsmanlike Driving, McGraw-Hill, 1975.

Bishop, Richard W., Robert M. Calvin, and Kenard McPherson, Driving:
A Task-Analysis Approach, Rand McNally and Co., 1975.

The Center for Safety Education, New York University, Driver Education
and Traffic Safety, Prentice-Hall, 1972.

Conversation with Bob Hall, Automotive Testing, Motor Trend,
July 28, 1977.

Conversation with Dan Sherman, Technical Editor, Car and Driver,
July 29, 1977.

Conversation with Glenn Brinks, Road and Track, July 28, 1977.

Conversation with Lee Baldrick, Testing Engineer, Consumer's Union,
August 29, 1977.

Federal Register, Vol. 31, No. 61, March 30, 1966, pp. 5170-5178.
Federal Register, Vol. 35, No. 136, July 15, 1970, pp. 11334-11359.
Federal Register, Vol. 37, No. 221, November 15, 1972, pp. 24250-24320.
Federal Register, Vol. 41, No. 138, July 16, 1976, pp. 29389-29393.

Hutchins, F. Peter, EPA/TAEB, Memo to Eric 0. Stork, EPA/OMSAPC,
"Transmission Shift Points", July 19, 1977.

Hutchins, F. Peter, EPA/TAEB, Memo to John P. DeKany, EPA/ECTD,
"Manual Transmission Shift Points on the FIP and HFET", May 4, 1977.

Jenkins, Rod, EPA/LVNP, Memo to Charles Gray, EPA/SDSB, "Automobile
Transmission Shift Points", Aug. 11, 1977.

Kaywood, Richard, et al, Drive Right, Scott, Foresman and Co., 1972.
Meetings with Paul P. Pataky and Donald R. Whitney, Environmental
Activities Staff, General Motors Corp., Sept. 2, Sept. 22, and
Sept. 28, 1977.

Perkins, Stuart R., American Motors, Letter to Richard A. Rykowski,
Environmental Protection Agency, Sept. 16, 1977.

Schwieder, W. E., Ford Motor Co., Memo to Charles Gray, EPA/SDSB,
"Passenger Car Shift Point Data", Aug. 22, 1977.


-7-

Historical Perspective of Federal Testing Procedures

The history of specifying shift points in driving cycles goes back to
March 30, 1966 (8). At that time, the California 7-mode cycle had just
become the Federal Test cycle. The shift points over this cycle were
set uniformly for all cars. The shift points were 15 mph, for shifting
from first to second gear, 25 mph, for shifting from second to third
gear, and 40 mph for shifting from third to fourth gear, if there was a
fourth gear.

This procedure remained until July 15, 1970 (9). At this time, the
modified LA-4 cycle with a cold start (1972 FIP) became the Federal Test
cycle. The development of this cycle involved operating a light-duty
vehicle over the Los Angeles driving route 4 and collecting vehicle
operational data. As the Driving Schedule developed from these studies,
it became clear that vehicles could be operated on chassis dynamometers
in a way that would reproduce the original trip characteristics. One
aspect of real life vehicle operation which received attention during
this development was the specification of shift points for manual trans-
mission vehicles.

In the course of this development, several manual transmission vehicles
(3, 4, and 5 speed) were driven over the schedule and the transmission
shift characteristics were evaluated. The 15-25-40 mph shift points of
the previous driving cycle were found to also be satisfactory for the
new Driving Schedule. Since the Driving Schedule was developed to
represent real life, and since real life drivers vary their gear shifting
characteristics to suit the driving conditions, it seemed unnecessary to
define rigid shift point specifications. It was expected that most
vehicles would be shifted at about the 15-25-40 shift points in real
life and that for vehicles which were likely to be shifted at other
speeds, the manufacturers would provide guidance in the owners manual.
With this in mind, the regulations were written to allow shifting at the
manufacturer's recommended shift points or at 15-25-40 in the absence of
such a recommendation, That the manufacturer's would recommend shift
patterns that would not represent the way that most people would, in
fact, shift those vehicles was not anticipated by the developers of the
Driving Schedule.

On July 16, 1976 (11), the 15-25-40 mph shift points were deleted completely
with the vehicles to be shifted according to the manufacturer's recommen-
dation to the ultimate purchaser. No stipulation was made for the case
where the manufacturer did not recommend shift points to the ultimate
purchaser.

An important question to ask would be what happens if a vehicle is
shifted too soon and cannot keep up with the driving trace? Currently
(10, 11), Federal regulations restrict any deviations of the actual
vehicle speed on the dynamometer from the speed shown on the driver's


~21-

gear approximately 50% of the time (50% shift speed) has been estimated
by linear interpolation and is also shown in Table #5. The engine speed
in % of rated RPM is also shown for each of these vehicle speeds. An
examination of the 50% shift speeds for all the vehicles again shows
very low variability in terms of % of rated RPM. In fact, there appears
to be no difference between the 2-3 shift and the 3-4 shift. The means
of both sets of data are 49% of rated RPM. This is not surprising since
the 2-3 shift of the 3 speeds and the 3-4 shifts of the 4 speeds are
both shifts into high gear. Also, the ability of the vehicle to hold a
constant speed should occur at approximately the same engine speed for a
given vehicle, regardless of the gear it is in. Thus, with all the data
in Table #5 analyzed together, the average 50% shift speed is 49% of
rated RPM and the standard deviation is 5% of rated RPM. The C-10 pick-
up was excluded from this final analysis because only a very small
portion of its data was available for re-analysis.

The cruise speeds where up-shifting occurred 50% of the time can
also be compared to the lower limit of the ranges of shifting speeds
recommended by the manufacturer when the vehicle is entering a cruise.
The lower limits are listed in Table #5. In all nine cases in Table #5
where comparisons can be made, the 50% shift speed is greater than the
lower limit of the manufacturer's recommended range of shift speeds,
which is used during certification. The differences range from 4% for
the 2-3 shift of the 6 cylinder Camaro to 55% for the 3-4 shift of the
Monza. The average difference of the nine cases is 27%. The owner's
manuals of the Chevette and Camaro (V-8) do not recommend a range of
shift speeds for entering a cruise for the 2-3 shift. The 2-3 shift
into a cruise for these two vehicles was still analyzed to allow the
number of vehicles to be as large as possible for determining the engine
speed at which shifting occurs upon entering a cruise.

At the same time the GM data was being re-analyzed for shifting
into a cruise from an acceleration, two other aspects of shifting which
are relevant to driving over the Federal certification driving cycle
were analyzed. First, the data were examined to determine if the vehicles
were being double-shifted as is recommended under certain conditions in
the owner's manuals. After examining thousands of shifts, only two
double shifts were found. Both occurred with the V-8 Camaro and were 1-
3 shifts at 22-25 mph. Shifts from first to third gear at this speed
are not recommended by the manufacturer. Where numerous occasions arose
where the manufacturers did recommend double shifting, not a single one
occurred,

Secondly, the situation of a vehicle entering a deceleration after
an acceleration was examined. The deceleration had to be at least 3
seconds long and had to begin within 3 seconds of the end of the accel-
eration (i.e., no cruising occurring between the acceleration and decel-
eration). This situation occurs a number of times during the certifica-
tion driving cycle and the shifting done at the transition appears to
assume that the 1 or 2 seconds spent at the peak speed is a cruise. It
was to verify this assumption that this particular analysis was performed.


-27-

Table #7
Urban
Shift Sequence HC co co NOx Fuel Econ.
(Grams per nite) (MPG)
Toyota TTC-1 Lean Burn
1* 1.14 6.43 295 1.55 28.7
3x* 1.06 6.73 314 1.60 27.1
Aer 1.06 6.69 332 1.51 25.7
VW Turbocharged Diesel
4k 0.42 0.93 226 1.01 44.5
5x* 0.50 1.00 252 1.24 39.9
1977 Chev. Chevette
2% 0.21 2.75 294 1.52 29.7
Ake 0.30 3.95 325 1.36 26.8
6%* 0.35 4.85 345 1.30 25.1
Shift Sequences Shift Points (MPH)
1-2 2-3 3-4 4-5
1 10 20 26 45
2 10 25 25-40%**
3 12 22 30
4 15 25 40
5 18 30 47
6

Shift using Peak Torque Bracketing

* Manufacturer's Recommended Shift Schedules.

*k = Shift Schedules more representative of in-use driving.

kkk Shift at highest speed shown unless cruise speed has been reached.


-3-

Table #2b: 2-3 Shift

Vehicles Camaro Camaro c-10 1976
(1977; GM) Monza Chevette Nova (L-6) (v-8) Pickup Rabbit
Average shift

speed from on the 28.4 27.2 34.6 36.9 28.4 36.2 30.9
road testing-mph (73) (68) (61) (65) (62) (61) (63)

(% of rated RPM)*

Cruise Speed at

which the vehicle

was shifted half 23 19 27 26 19 30 24
the time - mph (59) (48) (48) (46) (42) (51) (49)
(% of rated RPM)

Manufacturer's
Recommended 15-30 25 25-40 25-40 25 25-40 19-25
Shift Speed

RK

KKK

Manufacturer's Recommended

Average 50% Cruise Shift Speed
Speed Speed Upper Limit Lower Limit

Seven Vehicle
Average - MPH 31.8 23%* 32.1 --
(% Rated RPM) (65) (49)
Standard Deviation 4.0 3 7.6 --
MPH (% Rated RPM) (4) (6)
Four Vehiclex** - 25 -- 21.0

Average - MPH

GM's analysis. of road data for the 2-3 shifts of 4 speed vehicles
included only those shifts which resulted in continued acceleration.
Shifts into cruise made were included in the analysis of the 3
speed vehicles. Thus, these values for the 3 speed vehicles are
expected to be lower than the upper limit of the manufacturers
recommended shift speed.

C-10 pickup 50% cruise speed has been excluded because insufficient
data was available for reanalysis.

4 vehicle average is shown to allow comparison between cruise speed
and lower limit of manufacturers recommended shift speeds; excludes
Chevette, C-10 pickup, and V-8 Camaro.


-14-

Table #3
General Motors Test Results
1976

Vehicle Monza Chevette Nova Camaro Camaro Chevy C-10 VW Rabbit
(1977) (2.3L) (1.6L) (4.1L) (4.1L) (5.7L) (5.7L) (1.6L)

4-speed __4-speed 3-speed 3-speed 4-speed 3-speed 4-speed
Rated
RPM 4400 4800 3800 3800 3800 3800 5600
RPM at Max.
Torque 2400 3200 1600 1600 2400 2400 3200
RPM 1-2
Shift 3080 3310 2430 2700 2320 2400 3640
% Rated :
RPM 70 69 64 71 61 63 65
% RPM at
Max. Tqu. 128 104 152 169 97 100 114
N/V 1st gear
RPM/MPH 159.5 208 113 113 117 109 201
Vehicle
Speed 19.3 15.9 21.5 23.8 19.8 22.0 18.1
Manufacturer's
Recommended
Shift Spd. 10 10 20 20 15 15 15%
RPM 2-3 ‘
Shift 3210 3260 2320 2470 2356 2318 3528
% Rated
RPM 73 68 61 65 62 61 63
% RPM at
Max. Tqu. 134 102 145 166 98 98 110
N/V 2nd gear
RPM/MPH 113 120 67 67 83 64 114
Actual shift
Speed 28.4 27.2 34.6 36.9 28.4 36.2 30.9
Manufacturer's
Recommended
Shift Spd. 30 25 25-40 25-40 25 25-40 25%

*VW does not include specific shift points in their owner's manuals. They
use the old Federal shift schedule of 15, 25, and 40 mph for certification
testing.


-16-

and of the 2-3 shift data for the three speed vehicles. An unknown
number of these shifts were the result of the driver reaching the de-
sired vehicle speed and were not due to the normal limit of acceleration
in that gear being reached. This will have to be taken into account
when comparing this data to the shift speeds recommended by the manu-
facturers.

Ford tested a single 1976 Pinto over a city-suburban route to
determine the point at which the transmission was shifted between lst
and 2nd gears (14, 18). Four drivers were used in the study. The RPM
at the 1-2 shift was recorded off a tachometer by an observer in the
vehicle. The drivers could not read the tachometer, but did know the
purpose of the tests. The results are shown in the first column of
Table 4. The four driver average was 79% of the rated RPM.

The EPA study was conducted on the Marana Air Park grounds in
Marana, Arizona, by Wyles Laboratory (14). Eight vehicles were tested,
but only the three vehicles having standard transmissions are discussed
here. The drivers were employees of Evergreen Airlines, both men and
women, young and old. The vehicles were driven over a course consisting
of a loop with six stop signs. The drivers were told individually that
20 different drivers in three vehicles were being used to determine how
people normally drive. If questions arose, it was explained that engine
RPM and acceleration were being monitored to determine when people
normally shift gears. The drivers were instructed to drive normally and
were given one time around the loop to become acquainted with the course
before data was taken. The test under these conditions consisted of
five loops around the track or 30 sets of shifting through the gears per
driver. The results of the study are shown in Table 4. Again there is
good consistency for the 1-2 shift point in percent of rated RPM. In
this study, where the engines of the three vehicles were of very similar
size, the shift points in absolute RPM vary even less than in percent of
rated RPM.

The AMC study consisted of two vehicles, a 1977 Pacer and a 1977
Gremlin, instrumented to record the engine speed at the shift from lst
to 2nd gear (14). The drivers consisted of AMC personnel, who drove the
vehicles home overnight and returned them in the morning. The drivers
were not told that the vehicles were instrumented and the use of the
vehicles during the evening was not restricted. The two drivers, though,
did not normally drive cars with standard transmissions, but owned cars
with automatics. The results of this study are also shown in Table 4.
Again, the mean shift points of these two vehicles in percent of rated
RPM lie within the range of values set by the previously mentioned
studies. The Pacer shifted at 67% of rated RPM and the Gremlin at 63%
of rated RPM. The fact that the drivers were not used to driving with a
standard transmission did not seem to affect the results significantly.

Examination of all the data in Tables 3 and 4 shows that the 1-2
shift points of the vehicles vary significantly in absolute RPM (2320-
3940 RPM), percent of RPM at maximum torque (87%-169%), and vehicle
speed (15.7-23.8 mph). When the 1-2 shift points are normalized into


Table #2

Comparison of Average Actual Shift Speeds with Those Recommended by Manufacturers

Table #2a: 1-2 Shift

Vehicles Monza Chevette Nova Camaro Camaro C-10 1976 1976 vw Corolla Chevette Pacer Gremlin
(1977 (L-6) (v-8) Pickup Rabbit Pinto Rabbit
unless
noted)
(Tester) (GM) (GM) (GM) (GM) (GM) (GM) (GM) (Ford) (EPA) (EPA) (EPA) (AMC) (AMC)
Actual %
Rated 70 69 64 71 61 63 65 79 63 57 64 67 63
RPM
Actual*
Shift 19.3 15.9 21.5 23.8 19.8 22.0 18.1 23.3 17.3 15.7 16 18.7 18.8
Speed-MPH
Manufac-
turer's
Recom- 10 10 20 20 15 15 15 10 15 12 10 10-15 10-15
mended
Shift
Speed-MPH
Actual Percent Actual Shift Manufacturer's Recommended
Rated RPM Speed - MPH Shift Speed - MPH

Thirteen

Vehicle 66 19.2 14.0

Average

Standard

Deviation 5 2.7 3.5

*GM's analysis of the road data for the 1-2 shift used only those shifts which resulted in continued acceleration.

-t-


-25-

The idea that people do not shift as their owner's manuals recommend
is even more strongly confirmed by data gathered by the auto manufacturers
themselves and the EPA. Summarized in Tables #3 and #4, the results of
these four studies show that on the average, people shift into second
gear at a speed 44% greater than that recommended by the manufacturer.

(A recommended speed of 15 mph was used for the VW Rabbit, since this is
what VW recommends for use during certification.) The data ranged
between 8% greater for the Nova and 133% greater for the Pinto.

The results for the 2-3 and 3-4 shifts (Table #3) show that the
actual and recommended shift speeds are much closer to each other than
for the 1-2 shift. The three 4-speed vehicles with a recommended 2-3
shift speed of 25 mph were all shifted at higher speeds. The differ-
ences ranged from 2.2 mph (Chevette) to 5.9 mph (Rabbit). The 4-speed
Monza, with a recommended shift speed of 30 mph, was shifted earlier at
28.4 mph. Except for the VW Rabbit, these differences are small.

The 2-3 shift results for the three 3-speed vehicles are also more
difficult to interpret, though, because of the possibility of shifting
upon reaching cruise speed. The results show that at least the section
between 30 mph (Nova) or 35 mph (Camaro and C-10 pickup) and 40 mph are
representative of normal driving. Similarly, the 3-4 shift results
(Table #3) show that the upper section of the recommended shift speed
ranges are representative of normal driving (GM vehicles) for the 4-
speed vehicles. The VW certification shift speed of 40 mph appears very
representative.

To evaluate the representativeness of the lower end of the speed
ranges recommended by the manufacturers for shifting into a cruise, the
results of the re-analysis of the GM data can be used (Table #5). As
can be seen from the results in both tables, none of the vehicles is
being shifted most of the time at the lower limit of the shift speed
range recommended by the manufacturers. Overall, the speed where the
vehicles are shifted half the time is 27% greater than the lower limit
recommended by the manufacturers. Thus, it appears that in this area,
also, people shift later than the manufacturers recommend and, thus,
later than shifting is done during certification.

There are also sections of the certification driving cycle where an
acceleration is followed very closely by a deceleration. Under these
circumstances, the vehicle is often shifted as if it has entered a
cruise after the acceleration. It was felt that this might not be the
case in actual driving, so the General Motors data was re-analysed to
determine the representativeness of shifting into a deceleration as if
it were a cruise.

The results showed that for nine out of ten of the comparable cases
(Tables #5 and #6, 6 vehicles for 2-3 and 3-4 shifts), the shift into
decelerations occurred only at significantly higher speeds than did the
shift into cruises. For the 3-4 shift of the Chevette and the Camaro
(V-8), the peak speed where shifting occurred 50% of the time was even


-1-

Shift Schedules for Emissions and
Fuel Economy Testing

The aspect of shift schedules in emissions and fuel economy testing
is an important one. The timing of the shifting of gears over the
certification driving cycle has a significant effect on the emissions
and fuel economy of the vehicles tested. The purpose of this report is
to examine the current method of determining the shift schedules used
during certification and determine if this. method is resulting in shift
schedules which are representative of those used by typical drivers.

The history of the method of determining shift schedules for the certi-
fication process is first examined. Then the current trends of shift
schedules found in vehicle owner's manuals are determined, since these
are the sources of the shift schedules used during certification. Next,
the methods of determining shift schedules of other automobile testing
organizations are examined, as well as how people are taught to shift in
driver's education schools. Finally, data are presented comparing on-
the-road shift speeds to those recommended by the manufacturers.

A summary of the shift points recommended by the above sources is
presented in Table #1. In Table #2, results from studies examining the
actual shifting of vehicles on the road are compared to those shift speeds
recommended by the manufacturers. In Tables #2b and #2c, the average
shift speed is comparable to the higher limit of the manufacturer's
recommended shift speed, while the cruise speed at which up-shifting
occurred half the time is comparable to the lower limit.

Table #1

Comparison between Shift Points
Recommended by Various Sources

Historical Owner's Manuals Training Testing
Shifts _Perspective* Pre-1974** 74-76 76-78*** Manuals _ Organizations
1-2 15 - 10-20 10-20 10-15 -
2-3 25 - 20-30 15-30 15-25 -
3-4 40 - 30-40 20-50 35 -

* Previously required shift schedule included in Federal test procedures.
** Previous to 1974, few owner's manuals recommended specific shift points.

*kk =Many owner's manuals since 1976 include additional stipulations like
shift into the highest possible gear once cruise speed has been reached
and listing the range of cruise speeds for each gear. This can mean
recommending double upshifting. One manufacturer is also recommending
different shift points for a cold and a hot engine.

# Other testing organizations recommend that their drivers shift when it
seems reasonable.


-28-

only slightly and could be the basis for such a correlation. Or it
might turn out that after other parameters, such as vehicle weight,
horsepower, etc., are included, a better correlation would result using
absolute RPM. In either case, considerable time and effort would most
likely be needed to come up with such a correlation, which would be
similar to the one currently used for road load dynamometer settings.

To insure a reasonable amount of flexibility and accuracy, changes could
be allowed if the manufacturer could show that on the road data sup-
ported them, again similar to the method for determining road load
settings.

A second way to insure more representable shifting patterns would
be a simpler version of the first method. That would be to return to
the original 15-25-40 shifting pattern and then require the manufacturers
to demonstrate using test data why a different shifting pattern would be
more representative. This would require less time and effort than the
first method, but would put a large amount of work on the manufacturers
if they desired to change the shifting patterns of a considerable
number of cars. Both this method and the first would require a change
in the regulations governing emission and fuel economy test procedures.

A third method which could be implemented sooner and one which
shouldn't require a change in the statutes would be to require manufac-
turer's to demonstrate that their recommended shifting patterns are
representative. The need for representativeness is implicit in the
entire automotive pollution control and fuel economy program. Under
this method, any questionable patterns could be returned to the manufac-
turer asking for data supporting these patterns. Again, this method
would require little time and effort to implement.

The final method would simply be to allow the drivers to shift when
they think it is reasonable, always staying as close to the driving
trace as possible. This raises problems of increased variability due to
differences between drivers and also the need to change the regulations.
It does not require any lead time, though, as does the first method and
could be implemented as soon as the regulations could be changed.


-12-

Public Training in Shifting Gears

The explaination of shifting gears in driver's training manual is by
necessity quite general, since every engine-vehicle-drive train com-
bination cannot be discussed separately. Also, this aspect of driving
is often dealt with quickly, since most driver's education schools use
automatics, It is felt that this aspect of driving can be learned
quickly by those drivers who will need to drive vehicles with standard
transmissions (2, 3). Emphasis is placed on steering, braking and other
skills essential to safely operating all types of vehicles.

Those manuals which do deal with manual shifting have very similar
instructions (1, 2, 3, 15, 19). Most recommend shifting from first to
second gear at 10-15 mph, second to third gear at 15-25 mph, and third
to fourth gear (if applicable) at about 35 mph. One manual recommends
looking in the owner's manual to find the exact speeds at which to shift
gears (2). Another states that you can shift up one gear once you have
the car moving smoothly in the present gear (19).

One driver's training instructor in Ann Arbor, Michigan said that he
recommends to his classes that they shift by feel. That is, shift as
soon as the engine will run smoothly in that gear. Because this and
most other driver's training courses only use vehicles equipped with
automatic transmissions, any instructions given by instructors or manuals
are never practiced on the road. When new drivers do begin to drive
vehicles with standard transmissions, they will most likely learn from a
family member or friend and not from a licensed instructor or a manual.
This, coupled with the difficulty of driving a car while looking at the
speedometer, makes it highly unlikely that any shift speeds mentioned in
training or owners' manuals make any difference in the shifting habits
of the average driver. The shift speeds are most likely determined by
the ability of the vehicle to accelerate at the desired rate in the
present gear and the next highest gear. This can be determined by
engine sound and feel and does not require the driver to take his eyes
off the road.


-15-

Table #3 (continued)

General Motors Test Results

1976

Vehicle Monza Chevette Camaro VW Rabbit
(1977) (2.3L) (1.6L) (5.7L) (1.6L)

4-speed 4-speed 4-speed 4-speed
Rated RPM 4400 4800 3800 «5600
RPM at Max. 2400 3200 2400 3200
Torque
RPM 3-4
Shift 2770 2832 1860 3250
% Rated
RPM 63 59 49 58
% RPM at
Max Torque 116 90 78 102
N/V 3rd Gear
RPM/MPH 75.4 76.6 55.4 79.7
Actual Shift
Speed 36.8 37.0 33.6 40.8

Manufacturer's ’
Recommended 20-50 25-40 25-40 40%
Shift Speed

*VW does not include specific shift points in their owner's manuals. They
use the old Federal shift schedule of 15, 25, and 40 mph for certification
testing.