EPA-AA-IMS/ST-80-4
                                                          TEB 80-13
                          Effects of Gasohol on Idle
                              HC and CO Emissions
                                      by
                               Thomas Darlington
                        Inspection/Maintenance Staff

                              Richard Lawrence
                  Technology Assessment & Evaluation Branch
                                 March, 1980
                                   NOTICE

Technical Reports  do  not necessarily represent final EPA decisions or posi-
tions.  They are intended to present technical analysis of issues using data
which are currently  available.   The purpose  in  the  release  of such reports
is  to  facilitate  the  exchange  of  technical  information and  to  inform the
public  of  technical  developments  which  may form the basis  for  a final EPA
decision, position or regulatory action.
                    Emission Control Technology Division
                Office of Mobile Source Air Pollution Control
                     Office of Air, Noise, and Radiation
                    U.S. Environmental Protection Agency

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Summary

A  test  program was run  to  investigate the effects of  gasohol  on CO and HC
emissions  on  an  I/M  idle test.   Three  vehicles were  set-up  to operate on
either  gasoline  or  gasohol.   A Hamilton  emissions analyzer  was  used to
measure tailpipe  emissions.  CO  emissions were varied in each of  the cars by
adjusting  the  idle mixture screw, and HC emissions were varied by inducing a
misfire with  a misfire generator.   At each CO and HC value as specified in
the program,  the  fuel was switched from gasoline to gasohol while its effect
was noted  on  tailpipe  emissions.  The  data  obtained  provided  a basis for
determining  gasohol's  ability   to reduce  CO  and HC  emissions  for  an  idle
test.

As the cars were  maladjusted, gasohol was  found to reduce  idle CO about  1.1%
CO.   The  redaction in  idle CO  was  relatively constant  for  all three  cars
between  idle  mixture  settings  of 1.5%  and 7.0% CO,  and the catalyst  cars
experienced a  greater average reduction  (Figures 3-5).

Unlike the relatively constant  idle CO reductions, idle HC reductions attri-
buted  to  gasohol were vehicle  dependent.   A non-catalyst  car  experienced
practically no reductions,  a  catalyst car experienced an average  188 ppm
reduction,  and a  second  catalyst car experienced  a  complete reduction (to
zero) for  all  levels of HC tested  (Figures 6-8).

This  limited  data indicate that  a catalyst vehicle  just  passing New Jersey
standards  of  3.0% CO and 300 ppm HC on gasohol would emit about  4.1% CO and
480 ppm HC on  gasoline.   Similarly, a  catalyst vehicle  just passing  Portland
standards  of  1.0% CO and 225 ppm HC would  emit about 2.1% CO and 400 ppm HC
on gasoline.

Background
                            3
A  previous EPA test program  using a  test  procedure  similar  to  the,standard
FTP test on a fleet of  eleven passenger cars has shown  that gasohol  reduces
exhaust  HC mass  (gin/mile)  emissions by about nine  percent  and  reduces ex-
haust  CO  mass (gm/mile)  emissions twenty  to thirty-four  percent  compared to
gasoline.   However,  evaporative HC emissions, which  are not  measured in an
idle  test,  increased  62%, resulting in a net HC increase  on vehicles  fueled
with  gasohol.  The extensive  use of  idle  tests  in  State I/M programs  war-
ranted  determining gasohol emission characteristics  on an idle  test  proce-
dure.
T7A misfire  generator  works  by  grounding  the  primary  of  the  ignition  coil
    a controllable  percentage  of  time.
2]  Levels  of  HC  were  induced  by  misfire  to the limit of HC  observed  with
    this  car on gasoline (305  ppm HC).
3/  "Gasohol Test Program,"  Richard  Lawrence, TAER,  MVEL,  EPA,  December,  1978,
4/  10% ethanol,  90% Gasoline.

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Purpose

The  purpose  of this  study  was to investigate  the  effects of gasohol on  CO
and HC emissions in an I/M  idle test.

Test Program

Three vehicles  were set up to operate from  two  fuel  containers  at  the front
of the vehicles.  The vehicles used were a 1974  Ford  Maverick (no catalyst),
a  1977 Chevette (pellet catalyst), and a 1979  Ford Fairmont  (monolith cata-
lyst).  Vehicle specifications are tabulated in Figure  1.  A selector valve
was  set  up to  switch operation  of  the vehicles  between two fuels.  Fuels
used  were Indolene HO  (Fuel  1)  and 90%  Indolene +  10% Ethanol  (Fuel  2).
Indolene  HO   is  a  standard reference test  fuel.   The  change  in  emissions
caused by the addition  of  ethanol to Indolene  is  similar to tJie  change  in
emissions caused by the  addition of ethanol  to  commercial  fuel.

The following procedure  was used to test each vehicle in  each configuration:

     1.  Warm-up car  at  idle 15 minutes on Fuel  1.

     2.  Disconnect and  plug cannister line  to  carburetor.

     3.  Operate at 2500 rpm for  1 minute.

     4.  Drop back  to idle  and read HC, CO and  rpm.

     5.  Operate at 2500 rpm for  1 minute, read  HC, CO.

     6.   Switch to  Fuel  2 and  purge  (at 2500 rpm).

     7.  Drop back  to idle  and read HC, CO and  rpm.

     8.  Operate at 2500 rpm 1 minute, read  HC,  CO.

     9.   Switch back  to  Fuel 1 and purge  (at 2500  rpm).

     10.  Drop back to  idle and read HC, CO  and  rpm.

     11.  Change initial HC or CO  as  indicated  in  the following  configur-
     ations.
51  "Gasohol Test Program", Richard Lawrence
6_/  Cannister  line was  disconnected  to  reduce  test-to-test variability
    caused by  cannister loading  and purging.

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Target Configurations

1.  Adjustment of idle mixture screw to vary CO.

     a.  Fairmont and Chevette:  As-Received,  .3%,  .5%,  1.0%,  2.0%,  3.0%,
     4.0%, 5.0% CO.

     b.  Maverick:  As-Received, .3%,  .5%, 1.0%, 2.0%,  .  .  .  , 8.0%  CO.

2.  Inducement of misfire to vary HC.

     a.  Fairmont and Chevette:  As-Received,  100 ppm or  less, 200,  300,
     400, 500, 600 ppm Hexane.

     b.  Maverick:  As-Received, 100 ppm or less, 200,  300,  .... 900 ppm
     Hexane.

3.  Adjustment of idle mixture plus misfire to vary both  CO and HC.

     a.  Fairmont and Chevette:

          CO       2%        3%        3.5%         4%        5%          6%
          HC      200       300        350          400      500       600

     b.  Maverick:

          CO          2%            3%           4%          5%         6%
          HC         200           300         400        500        600

Results and Discussion

Before  testing,  both Hamilton analyzers were  calibrated according  to manu-
facturer  procedures  with  gas  standards  available  at  MVEL.   Calibration
results are explained in Figure  2.

During  testing,  it  was found  that numerous  "flow faults"  occurring  In  the
gas sample  line  of  the analyzer were  caused  by excessive  water  build-up  in
the gas  sample  line.  A water  trap  was  added to the sample  line to prevent
this  condition  from occurring.  Sample  line  modification is  illustrated  in
Figure 2.

Also  during  testing it was found  that one of the  test cars  (1979 Fairmont)
had a return line  from the  fuel  pump to the  gas  tank.  When remote tanks
were  connected  to  the  fuel pump,  unused  fuel  from these tanks  was drained
into  the vehicle's  main  tank.   This  situation was remedied by returning
unused fuel to the  inlet side  of the fuel  pump.

The following list  of  comparisons explains  results  obtained from  testing.
Data  is graphed and  tabulated  in the Appendix.
7/  A "flow  fault" condition  is  observed  on  the  analyzer in  the form of an
    indicator  light whenever  flow  is  restricted  in  the  sample  line.

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When Idle Mixture Screw was Adjusted:

1.  Idle CO decreased on gasohol compared to gasoline by  an  average  of  1.14%
CO  between  idle settings"  of  1.2%  CO and 8.4%  CO.   A clear illustration  of
this decrease  is shown  for each car  in Figures  9-11.  The  two  catalyst cars
experienced a  greater  average reduction of CO  (1.28% CO) than  the non-cata-
lyst car (.90% CO).

2.  At 2500 rpm:

     a.   In the non-catalyst  car  CO emissions were less  on  gasohol  than
     gasoline by 1.45% CO.

     b.   In the catalyst  cars,  CO emissions were  nearly zero for  all con-
     figurations (both gasoline and gasohol).

When Misfire was Induced with a Misfire Generator:

3.   Idle HC decreased  on gasohol  compared to  gasoline by  an average  of:

     a.  31 ppm  Hexane for the non-catalyst car  over  a range of 100-700 ppm.

     b.   188 ppm for the pelleted catalyst car  over  a range of 300-700 ppm,
     and

     c.   100%   reduction  for four  configurations  tested  on the monolithic
     catalyst car  (70-305 ppm).

These results are  illustrated graphically in Figures  12-14.

4.  At 2500 rpm, average HC emission  on gasohol:

     a.  Decreased  in the non-catalyst car  63 ppm from gasoline.

     b.   Remained  relatively stable  at zero  for  both  catalyst cars  (both
     gasoline and  gasohol).

When Idle Mixture  Screw was Adjusted  While  Misfire  was Induced:

5.   Idle  CO decreased on  gasohol compared  to gasoline by an average of .85%
CO  (three cars).

6.   Idle  HC was almost unchanged  in  the non-catalyst car,  but decreased on
gasohol  compared to  gasoline on  the catalyst   cars  an  average of  109 ppm.

These results are  illustrated graphically in Figures  15-17.

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Conclusions

Limited data  gathered  from this test program clearly demonstrates gasohol's
ability to reduce CO and HC emissions at idle as compared  to gasoline.  Idle
emissions decreased on gasohol compared to gasoline by about 1.1% CO and 200
ppm  HC  on two  catalyst  equipped vehicles when  they  were  operated close to
New Jersey I/M standards of 3.0% CO and 300 ppm FC.

Evaporative HC  emissions  and NOx exhaust emissions  are  not measured during
the  I/M  idle  test.  However,  data taken  during  the earlier  Gasohol Test
Program   indicates  that   these  emission  components  increase   on  gasohol.

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                   Appendix
Figure
Figure
Figures
Figures  6-8
          1   Vehicle Specifications
          2   Analyzer Sample Line Modifications
         3-5  CO on Gasoline (% CO) vs. Change in CO
              from Gasoline to Gasohol
              HC on Gasoline (ppm HC) vs. Change in HC
              from Gasoline to Gasohol
Figures  9-11 Idle CO:  Gasoline vs. Gasohol (% CO)
Figures 12-14 Idle HC:  Gasoline vs. Gasohol (ppm HC)
Figures 15-17 Idle CO vs. HC:  Gasoline to Gasohol

Table     1   Idle CO - Gasoline vs. Gasohol
Table     2   2500 rpm CO - Gasoline vs. Gasohol
Table     3   Idle HC - Gasoline vs. Gasohol
Table     4   2500 rpm HC - Gasoline vs. Gasohol
Table     5   Idle CO*and HC - Gasoline vs. Gasohol
              (combined misfire and idle mixture adjust)

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                                    8
                       Figure 1 Vehicle Specifications
Identification
Mileage
Year
EGR
Air Pump
Catalyst
Eng. Configuration
Displacement
1974 Maverick

G12-28104
60500
1974
Yes
Yes
None
6-inline
250 CID
1977 Chevette

EPA-128435
6600
1977
Yes
No
Pellet
4-inline
85 CID
1979 Fairmont

G51-11375
1000
1979
Yes
No
Monolith
4-inline
140 CID

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     Fig. 2.  Sample Line Modification:  Hamilton Analyzers

     Diagram shows addition of water trap to stock sample line.
                Additional Sample
                Line Plus Probe
            Tailpipe
                        Stock
                        Sample
                        Line
                                          Water
                                          Trap
                                                           Analyzer
Calibration of Analyzers

Hamilton Computerized Emissions Analyzers were used to measure tailpipe emissions
during testing.  The manufacturer states the analyzer can detect HC and CO in
the following ranges and tolerances'"?:
          Emission

             CO
             HC
    Range             Tolerance

0.0 - 10.0%          +3% of full scale
0 - 2000 ppm (hex.)  +3% of full scale
The analyzer was calibrated before testing began according to manufacturer
procedures using gas standards     °^ HC anc* co in t'ie following concentrations:
                          Gas

                          HC
                          CO
               Concentration

               3815.5 ppm propane
                  5.158% CO
*  Autosense Owner's Manual, Hamilton Test Systems, Autosense Service Center,
   900 River Street, Windsor, Connecticut 06095.

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                                        10
Figures 3-5. CO on  Gasoline
(% CO) vs.  Change  in CO  (% CO)
From Gasoline to Gasohol.   All
Changes are reductions.

                Figure 3
        I07« HMVCnlCR
  I.I
  1.0
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                   X  X
    Oltt«ll7
             CO OH MIDI I ME. X
                                            Figures 6-8.HC on Gasoline
                                            (ppm  HC) ys.  Changes  in HC  (ppm HC)
                                            From  (gasoline to Gasohol.   All Changes
                                            are reductions.
 tio

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Figures 9-11.Idle CO:  Gasoline

vs.  Gasohol  (%  CO)
                                        11
                         Figures  12-140Idle HC;   Gasoline

                         vs. Gasohol (ppm HC)
            Figure 9
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                                     14



           Table 2. 2500 rpm CO Gasoline vs. Gasohol, Maverick Only*


     % CO Gasoline            % CO Gasohol        Diff.          % Diff.
AR      3.96                      2.30             1.66            42
        4.82                      3.28             1.54            32
        4.40                      2.99             1.41            32
        4.62                      3.49             1.13            24
        4.10                      3.00             1.10            27
        4.31                      2.81             1.50            35
        4.24                      3.27              .97            23
        4.92                      1.78             3.14            64
        3.77                      3.19              .58            15

Average of Differences (column 3)

1.45 (s = .36)
* Chevette  and Fairmont  exhibited no  difference  in  2500  rpm  gasoline  and  gasohol
  readings  (approximately  zero  % CO on both  fuels).

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                                      15
                     Table 3. Idle HC Gasoline vs. Gasohol


     HC ppm Gasoline          HC ppm Gasohol        Dlff.        % Diff.

                                1974 Maverick

*AR      185                       175               10             5
         290                       230               60            21
         340                       330               10             3
         395                       395                0             0
         440                       390               50            11
         505                       490               15             3
         605                       535               70            12
         700                       670               30             4

                                1977 Chevette

AR       300                       180              120            40
         400                       300              100            25
         500                       200              300            60
         600                       380              220            37
         700                       500              200            29

                                1979 Fairmont**

          73                         0               73            100
         160                         0              160            100
         210                         0              210            100
         305                         0              305            100

Average of Differences  (column 3)

Maverick    31  (s = 26)
Chevette   188  (s = 81)
Fairmont:  All  reductions were 100% reduction.
*  "AR" is as-received condition.
** 305 ppm HC on gasoline was HC reading  at  10.0% misfire.

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                                      12
          Figures 15-17.   Idle CO vs. HC;   G asoline to  Gasohol

          Idle CO was adjusted with idle mixture screw while HC
                   was adjusted with nisfire generator.
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                                    13
                    Table 1. Idle CO:  Gasoline vs. Gasohol
     % CO Gasoline
*AR      .68
        1.19
        1.85
        2.78
        3.29
        3.96
        5.08
        6.10
        6.22
AR       .86
        1.60
        2.21
        2.89
        3.72
        4.73
        6.10
                              % CO Gasohol

                                 1974 Maverick

                                   .42
                                   .61
                                  1.05
                                  1.76
                                    ,40
                                    ,06
                                    ,95
                                    ,10
                                  5.33

                                  1977 Chevette

                                    .01
                                    .20
                                  1.05
                                  1.15
                                  2.04
                                  2.91
                                  4.95
                Diff.
                  .26
                  .58
                  .80
                 1.02
                  .89
                  .90
                 1.13
                 1.00
                  .89
                                                    .85
                                                   1.40
                                                   1.16
                                                   1.74
                                                   1.68
                                                   1.82
                                                   1.15
                                                                  % Diff.
                                                                   38
                                                                   49
                                                                   43
                                                                   37
                                                                   27
                                                                   28
                                                                   22
                                                                   16
                                                                   14
                                 98
                                 87
                                 52
                                 60
                                 45
                                 39
                                 19
                                  1979 Fairmont
AR
         ,21
         ,83
         ,53
         ,03
         ,10
         .15
         ,10
         ,97
        6.98
        8.37

Average of Differences  (column 3)
 .01
 .02
 .01
 .92
1.98
 .07
 ,49
 ,20
6.42
7.17
                                   3.
                                   3.
                                   5.
                                                     .20
                                                     .81
                                                    1.52
                                                      11
                                                      12
                                                      08
                                                      61
                                                     .77
                                                     .56
                                                    1.20
Maverick
Chevette
              .90 (s = .16) Excluding leanest point.**
             1.40 (s = .36)     "        "       "
Chevette and 1.28 (s = .30) Excluding leanest points.
Fairmont
Fairmont     1.13 (s = .35) Excluding leanest two points.
Total        1.14 (s = .36) Excluding leanest points.
                                                                    95
                                                                    98
                                                                    99
                                                                    55
                                                                    36
                                                                    26
                                                                    31
                                                                    13
                                                                     8
                                                                    14
* "AR" is As-received condition.
** Leanest points were excluded because  average  reduction is greater than
   CO gasoline initial setting.

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                                      16
                   Table 4. 2500 rpm PC Gasoline vs. Gasohol

                                Maverick Only*

     HC ppm Gasoline          HC ppm Gasohol        Diff.         % Diff.

         205                        190               15              7
         305                        265               40             13
         340                        325               15              4
         445                        370               75             17
         450                        360               90             20
         575                        505               70             12
         665                        590               75             11
         800                        680               120             15

Average of Differences  (column 3)

63 (s = 37)
* Chevette  and Fairmont  exhibited  very  low (less than  20 ppm)  HC levels
  at 2500 rpm for  both gasoline  and  gasohol.

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    Table  5- Idle  CO  and HC:   Gasoline vs.  Gasohol
m

2
I
\o
CD
Combined idle mixture adjustment
% CO Gasoline

1.90
2.35
3.40
4.45
5.10

.92
1.2
2.0
3.0
4.3
5.0

1.29
1.75
2.82
3.40
4.50
% CO Gasohol %

1.23
2.50
2.90
3.30
4.40

.01
.52
.60
1.85
3.60
4.20

.01,,
.30
1.70
2.80
3.90
Average of Differences
Maverick
Chevette
Fairmont
Catalyst Cars


1
(Chevette &
and
CO*

.67
.15
.5
1.15
.7

.91
.68
1.4
1.15
.70
.80

1.28
1.45
1.12
.60
.60
% CO
.57
.94
.01
.97
misfire induced
Diff. % Diff

35
6
15
26
14

99
57
70
38
16
17

100
83
40
18
13
Diff
(s = .47)
(s = .28)
(s = .39)
(s = .32)

HC ppm Gasoline
1974 Maverick
200
300
400
500
600
1977 Chevette
165
210
240
360
465
600
1979 Fairmont
73
200
300
400
500
ppm Diff.
2 (s = 18)
110 (s = 61)
107 (s = 39)
109 (s « 49)
                                                                                  HC ppm Gasohol     ppm Diff.
                                                                                      220
                                                                                      320
                                                                                      400
                                                                                      480
                                                                                      590
                                                                                         6
                                                                                       78
                                                                                       60
                                                                                      245
                                                                                      440
                                                                                      550
                                                                                        0
                                                                                        30
                                                                                      210
                                                                                      300
                                                                                      400
 20+
 20+
  0
 20
 10
159
132
180
115
 25
 50
             Diff
10+
 7+
 0
 4
 2
96
63
75
32
 5
 8
73
170
90
100
100
100
85
30
29
20
       Fairmont)
     '+" sign  means increase in emissions

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