73-12
A Second Evaluation of the
Echlin Retrofit Emission Control System
January 1973
Thomas C. Austin
Test and Evaluation Branch
Environmental Protection Agency
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Background
In October of 1972, EPA's first report on the Echlin retrofit
system was published. While the EPA testing did indicate that
the installation of the Echlin system could result in significant
reductions in a vehicle's NOx emissions, it appeared that it was
the adjustments (mainly timing modifications) recommended with
the Echlin device installation rather than the Echlin device
itself that were causing the NOx reductions. Representatives of
the Echlin Manufacturing Company had reported that their device
allowed timing to be retarded without experiencing the temp-
erature and performance penalties normally associated with such
modifications. The EPA series of tests indicated, however, that the
Echlin system did nothing to improve engine cooling or eliminate
the fuel economy penalty associated with retarded spark timing.
Echlin provided us with the results of a 24-car fleet test of
their system which indicated a 26% reduction in hydrocarbons,
5% reduction in carbon monoxide and a 44% reduction in oxides of
nitrogen was achieved with the use of the Echlin system.
Since the earlier EPA evaluation seemed contrary to those Echlin
personnel had run, it was decided to schedule a new series of
tests on a later model vehicle, one more representative of the
class of vehicles for which the Echlin system is certified in
California.
System Tested
The complete Echlin system consists of:
1. An "ultra-sonic generator" (air bleed-type device reportedly
designed to produce ultra-sonic energy which in turn creates
"a new combustion environment").
2. A carburetor spacer plate.
3. Tubing, which is used to connect the generator to the
spacer plate.
4. Gaskets necessary for removal and replacement of the
carburetor.
In addition to the installation of this hardware, Echlin
recommends that the spark timing be retarded to 2° BTDC, the
idle CO be set to 2% and the vacuum advance line be disconnected
and plugged. The kit for this particular car also included
a replacement for the vacuum advance unit to eliminate any
breaker plate wobble which might occur.
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Vehicle Tested
The vehicle used in this evaluation was a 1970 Chevrolet Impala
powered by a 350 CID engine with a two-barrel carburetor. This
vehicle is equipped with an automatic transmission. j
"i
Test Program j
The 1975 Federal Test Procedure was used to determine exhaust ',
emission levels. Details of this procedure can be found in j
Attachment I of this report. Four different configurations
of the vehicle were tested: j
1. Baseline, no modifications.
2. Same as above except vacuum spark advance was ;
disconnected and plugged and timing was retarded 7
to 2° BTDC per Echlin specifications.
3. Complete Echlin system including disconnect of
vacuum advance, 2° BTDC timing, 2% idle CO, and
the "ultra-sonic generator".
4. Same as above without Echlin "ultra-sonic generator"
device installed.
In each of these configurations fuel consumption was determined
using both carbon balance and weighing techniques.
Test Results f
Emission test and fuel consumption results are summarized in e
Table I. r
The complete Echlin system reduced hydrocarbons slightly (18%),
increased carbon monoxide significantly (77%), and reduced oxides
of nitrogen slightly (13%). There was a 7% fuel economy penalty
associated with the use of the complete system.
Removal of the Echlin "ultra-sonic generator" device, while \
leaving all other adjustments recommended by Echlin the same, [;
resulted in HC emissions 1% higher than baseline, CO emissions j
220% higher than baseline, and NOx emissions 18% lower than }
baseline. A fuel, economy penalty compared to baseline of 14% p
was measured.
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Returning the idle CO level to the baseline setting
while leaving the vacuum advance disconnected and the
timing retarded produces the lowest emission levels of
the test series. Hydrocarbons were 361 lower than the
baseline, carbon monoxide was increased only 12% and
oxides of nitrogen were reduced 28% from the baseline. •
Fuel economy was only 4% poorer than baseline. . j
No adverse driveability was noticed in any of the four •
configurations.
Conclusions from the Testing
1. The timing modifications recommended by Echlin reduced
hydrocarbon and oxides of nitrogen levels significantly. •
2. The idle CO levels recommended by Echlin significantly
increased the carbon monoxide level.
3. The Echlin hardware itself had no beneficial effects
on emissions or fuel economy. The "ultra-sonic generator" '
portion of the Echlin system causes some enleanment of
the mixture which can be cancelled out or over-'compensated
for by enrichening the idle CO setting of the carburetor.
Using the recommended timing modifications (vacuum spark
advance disconnect and 2° BTDC) without the Echlin system
resulted in lower HC emissions, lower CO emissions, lower
NO-x emissions, and better fuel economy than was achieved
Using the Echlin hardivare.
4. System installation required removal and replacement
of the carburetor and modification of the choke linkage.
Some vehicles may require modifications to the heat stove '•"•
since there may be sealing problems after the spacer plate i
is installed below the carburetor. ^
\
Comments . i.
1. The timing modifications recommended by Echlin should (
reduce hydrocarbon and oxides of nitrogen levels from most
in-use vehicles.
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2. The idle CO levels recommended by Echlin could
significantly increase the carbon monoxide levels of
many in-use vehicles. '.
3. The Echlin system may cause durability (valve burning)
and eventually emission problems on some vehicles because
there is no provision for restoring vacuum spark advance
when engine temperature is high. Temperature problems
could be anticipated from the fuel economy penalty
measured.
It should be noted that these conclusions and comments
do not necessarily contradict the results of the Echlin 24-
car fleet test. These conclusions indicate, however, that
the Echlin Company might have been able to achieve greater
emission reductions with less fuel economy penalty had
they only altered the timing of those 24 vehicles and not
installed their device and reset the idle CO.
T
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TABLE I
Echlin Device Test Series
1975 Federal Test Procedure
(all emission data in grams per mile)
Test No. EC
CO
NOx
MPG
Baseline
VSAD and
2°BTDC
% change
16-0053
16-0063
16-0074
AVERAGE
16-0170
16-0179
16-0193
16-0163
AVERAGE
1
1
2
1
1
1
1
1
1
from baseline
Echlin
System
% change
16-0108
16-0112
16-0113
AVERAGE
from baseline
VSAD, 2%
CO, 2°BTDC
16-0090
16-0092
16-0096
AVERAGE
1
1
1
1
.67
.83
.11
.87
.16
.21
.13
.26
.19
36%
.62
.49
.52
.54
-18%
1
1
1
1
.93
,86
.88
.89
17
16
18
17
21
20
16
20
19
.96
.55
.28
.6
.61
.57
.26
.44
.72
+ 12%
30
32
30
31
.99
.04
.19
.07
+77%
57
55
56
56
.09
.60
.11
.27
3.
3.
3.
3.
2.
2.
2.
2.
2.
37
28
23
29
34
37
26
49
37
-28%
3.
2.
2.
2.
08
64
87
86
-13%
2.
2.
2.
2.
72
78
61
70
12.
11.
11.
11.
11.
11.
11.
11.
11.
-4%
11.
11.
11.
11.
-7%
10.
10.
10.
10.
1
9
3
8
0
2
5
6
3
0
0
1
0
2
2
1
2
% change
from baseline
+1%
+220% -18%
-14%
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