EPA-AA-TEB-81-6
Testing of Five Diesel-Powered Passenger Cars
          at High and Low Altitude
               Thomas A.  Tupaj
                October 1980
         Test and Evaluation Branch
    Emission Control Technology Division
      Motor Vehicle Emission Laboratory
    U.S. Environmental Protection Agency

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Abstract

A group  of  five  in-use diesel-powered passenger cars was tested for emissions
and fuel economy  at  both high altitude and  low altitude locations.  The test
sequence consisted of the current Federal Test Procedure (FTP) and the Highway
Fuel Economy Test  (HFET).   Particulate emissions were also measured over both
cycles at both locations.  On the average, a substantial increase was noted at
high altitude  for hydrocarbons,  carbon monoxide and  particulates  as compared
to  the  low  altitude measurements.   As  measured  over  the FTP,  the average
increases  for  these  three  pollutants  were  130%,  75% and  45% respectively.
Results  of  the HFET  were in the same direction but were of a slightly smaller
magnitude.   The emission  levels  of oxides of nitrogen  were  approximately the
same at  each  location.   The average fuel economy values at high altitude were
approximately 14% lower than those at low altitude.

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Background

Although the  diesel  engine has long been used  as a powerplant for commercial
vehicles,  its  application to  passenger  cars had been  limited  due  to factors
such as weight, noise and cost.  The changing economic and political situation
has recently made this concept more feasible.  Although several manufacturers,
such as  Mercedes-Benz  and Peugeot,  have been in the market for some time, the
diesel engines  recently  introduced by Oldsmobile and  Volkswagen  have quickly
gained  a  small  but growing  share of new-car  sales.   Because the potential
exists for widespread use of diesel engines in all parts of the country,  there
is  a  need to  obtain information concerning the emission  levels  of these ve-
hicles when operated at high altitude locations.

Purpose

The purpose of  this project was to assess the effect of altitude  on the emis-
sion characteristics of   diesel-powered,  in-use passenger cars.  This  infor-
mation will be  used to project the emission characteristics of the high alti-
tude fleet as well as for evaluation of new or expanded standards.

Program Design

This program  was developed to  test  a  sample of vehicles  at  low  altitude and
subsequently  at  high  altitude.  The  low  altitude  testing was  performed  at
EPA's Motor Vehicle  Emission  Laboratory  (MVEL)  in Ann Arbor.  Testing at high
altitude was performed by Automotive Testing Laboratories  (ATL) in Aurora, CO.
The  vehicles  were  tested at  each  location without mileage  accumulation  or
adjustments between  the   test  sequences.  The same fuel was also  used at both
locations.  The test sequences consisted of the current Federal Test Procedure
(FTP) and  the Highway Fuel  Economy Test  (HFET).   Particulate  emissions were
also measured during each of these driving cycles.

The vehicles chosen for this program represented the more common diesel  engine
passenger  cars  available to  the  consumer.   All were in daily  use  by private
owners at  the  time  they  were  recruited into the program.  The characteristics
of the test vehicles are as follows:

#241 1980   Volkswagen  Rabbit:    4   cylinder;    90   CID;   Manual   5   speed;
     VIN-17A0815408; Engine Family-D; Odometer-5579

#242 1979  Oldsmobile Cutlass  Supreme:   8 cylinder;  260  CID;  Automatic  trans-
     mission;  VIN-3R47P9M535761; Engine Family-930H9; Odometer-8930

#243 1979  Oldsmobile  Cutlass  Supreme:   8 cylinder;  260  CID;  Automatic  trans-
     mission;  VIN-3R47P9M540008; Engine Family-930H9; Odometer-13301

#244 1974  Peugeot   504:   4   cylinder;   129  CID;   Manual   4  speed;   VIN
     504D90-1759613; Odometer-73252

#245 1977  Mercedes  Benz   240D:   4  cylinder; 147  CID;  Automatic transmission;
     VIN-123.123-12015320; Engine Family-77/2/L-4D/2.4; Odometer-52206

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Conduct of the Program

The responsibility  for  the project was assigned  to  Automotive  Testing Labor-
atories in April,  1980,  under EPA contract No. 68-03-2891.  They arranged for
the procurement  of  the  vehicles through  a  leasing firm  in St. Louis.   The
vehicles were  shipped to  Ann Arbor in  May.   Upon arrival at  the  MVEL,  each
vehicle was  inspected to  insure it was  in proper  operating order.   Two  or
three test sequences were performed on each vehicle to obtain the low-altitude
baseline.   The  vehicles were  then  shipped to  the Denver  area  for  testing  by
ATL at their laboratory in Aurora.  Identical test procedures using equivalent
test  equipment  were performed  there  in July.   No maintenance  or adjustments
were  performed  on any vehicle before testing at the  high-altitude location.

Test Results

The average FTP emission levels for each vehicle at each location are shown in
Table  1.   Results from the HFET  are displayed in Table 2.  A  listing of all
test  results  on  each  vehicle  is attached  as  Appendices A and  B while ATL's
report on  the  program (Reference 1) contains  details  on  the  test procedures.

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                           Table 1




Average FTP Emission Levels of Diesel-Powered Passenger Cars
Vehicle
#241 80 Volkswagen
90 CID
Odometer-5579
#242 79 Olds
260 CID
Odometer-8930
#243 79 Olds
260 CID
Odometer-13301
#244 74 Peugeot
129 CID
Odometer-73252
#245 77 Mercedes
147 CID
Odometer-52206
Average (all vehicles)
Increase
Average (without #244)
Increase
Test
Site
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
HC
(g/mi)
.57
.22
1.39
.68
.97
.39
6.74
3.86
.65
.25
2.06
1.08
91%
.89
.38
134%
CO
(g/mi)
1.88
.78
2.21
1.50
2.57
1.49
8.88
3.83
1.04
.67
3.32
1.65
101%
1.93
1.11
74%
NOx
(g/mi)
1.09
1.05
1;29
1.43
1.56
1.67
.98
.93
1.51
1.29
1.28
1.27
1%
1.36
1.36
0%
F.E.
(mi/gal)
35.3
39.5
20.5
22.9
20.6
24.2
21.0
25.2
25.8
31.8
23.6
27.6
-14%
24.3
28.2
-14%
Part.
(g/mi)
.40
.26
.98
.78
1.82
1.13
2.43
2.43
.47
.36
1.22
.69
78%
.92
.63
46%

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                           Table 2




Average HFET Emission Levels of Diesel-Powered Passenger Cars
Vehicle
#241 80 Volkswagen
90 CID
#242 79 Olds
260 CID
#243 79 Olds
260 CID
#244 74 Peugeot
129 CID
#245 77 Mercedes
147 CID
Average (all vehicles)
Increase
Average (without #244)
Increase
Test
Site
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
HC
(g/mi)
.35
.13
.47
.29
.36
.22
1.87
1.44
.26
.13
.66
.44
50%
.36
.19
89%
CO
(g/mi)
1.42
.47
1.04
.79
1.27
.82
3.55
1.70
.63
.57
1.58
.87
82%
1.09
.66
65%
NOx
(g/mi)
.81
.73
1.20
1.23
1.45
1.59
1.08
.88
1.68
1.42
1.24
1.17
6%
1.29
1.24
4%
F.E.
(mi /gal)
42.7
51.8
28.5
32.0
29.1
33.6
25.9
33.1
28.3
33.5
30.0
35.6
-16%
31.2
36.3
-14%
Part.
(g/mi)
.34
.19
.72
.48
1.12
.74
.69
.38
.23
.36
.62
.43
44%
.60
.44
36%

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Discussion of Test Results

As seen  in  Tables 1 and 2, the emission levels of unburned hydrocarbons (HC),
carbon  monoxide  (CO)  and particulates  for  each vehicle  were substantially
greater at high altitude.  Despite this increase, the average levels for three
of the vehicles are still below the standards under which they were certified.
In the  case of  the 1980  Volkswagen,  however, the  effect  of  altitude  on HC
emissions put  it over its  .41  g/mi  standard.  The  1974  Peugeot  failed HC at
both  altitudes.   Although  the  emission  levels  of  oxides of  nitrogen (NOx)
increased very slightly,  the  scatter  in  the  data  implies that  the  overall
change in emissions  of this pollutant may not be significant.   Since vehicle
No. 244, the  1974 Peugeot, was so different from the rest, in age, appearance
and   performance,   the  possibility   exists   that   it   had  been  improperly
maintained.  It  could  be  concluded that this vehicle may not be representative
of  the   current  fleet.   Therefore,  the averages have  also been calculated
without  its results.   These  values are also shown on Tables 1 and 2.  For the
remaining vehicles,  the  fuel  economy penalty  for operation  at high altitude
was quite apparent and consistent at  about 14%.

Shown in Table 3 are  the  emission rates and fuel economy of a representative
fleet of late  model,  gasoline-powered passenger  cars tested  at high altitude
(Reference  2).   These  may be compared to the  results  of the four late model,
diesel-powered cars tested in this program.

                                     Table 3

Estimated Emission Levels of Late Model Passenger Cars at High Altitude (g/mi)
                                            FTP
                                 H£      C0_     NOx     Part.

These four late model            .9     1.9     1.4      .9       '    .6
diesel-powered cars

Typical Late-model, gasoline-
powered cars (average odometer  2.6    45.0     1.2       *            *
20,000 miles)

*Data on particulate emissions from gasoline-powered vehicles is currently
 being obtained in another test program.

Table 4 is  a listing of  these percentage  increases compared to average emis-
sion  and  fuel  economy changes  expected  of  low  altitude vehicles  which  are
tested at high  altitude.   For the gasoline-powered vehicles the projection of
emission changes was  derived from information contained in  Reference  2.   The
values for  fuel economy  penalty were  determined  by a  comparison  of  results
between identical  vehicles  tested  at high and  low  altitude  sites  in the FY79
Passenger Car Emission Factor Testing Program.

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                                     Table 4

           Changes In from Low Altitude Baseline Emissions (g/mi) and
                     Fuel Economy (mi/gal) at High Altitude
                                             FTP                    HFET
                              HC    C£    NOx    MPG    Part.    MPG    Part.

Four late-model diesel-     +134%  +74%    0%    -14%   +46%    -14%    +36%
powered cars

Typical late-model gaso-
line powered cars           + 35%  +80%   -35%   - 7%    *     - 7%      *

*Data on particulate emissions from gasoline-powered vehicles is currently
 being obtained in another test program.

Conclusions

Based on  the  results  of this program  there  are several conclusions which may
be drawn:

     1.   Diesel-powered passenger  cars tuned to operate at  low altitude and
          subsequently operated at high altitude produce substantially greater
          amounts of HC, CO and particulates.

     2.   Despite  their increased  levels,  HC and  CO emissions  from diesel-
          powered  cars  are  still  much   lower  than   those   from  similar
          gasoline-powered vehicles  operated at high altitude.   On the other
          hand,  levels  of particulates may become  of  even  greater concern.

     3.   There is a  penalty in fuel economy apparent when a vehicle designed
          for  low altitude  is  operated  at  high  altitude.  Diesel vehicles
          appear  to suffer  more than gasoline-powered models with  respect to
          fuel economy.

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References
     1.   Report from Automotive Testing  Laboratories  entitled "Tests on Five
          Diesel  Passenger   Cars   at  High   Altitude",   EPA  Contract   No.
          68-03-2891, Task #1, September 1980

     2.   Jay S. Wallace,  "Draft Compilation of Air Pollutant Emission Factors
          for On-Highway Mobile Sources,  (AP-42)".

     3.   Report  from  Automotive  Testing  Laboratories entitled  "Effect  of
          Altitude on Maladjusted Vehicles", EPA Contract No. 68-03-2891,  Task
          No. 2, Due November, 1980.

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