73-7
An Evaluation of the Echlin
Retro-fit Emission Control
System
October 1972
Thomas C. Austin
Test and Evaluation Branch
Environmental Protection Agency
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Background
In March of 1972 the Echlin Manufacturing Company contacted
EPA's Mobile Source Pollution Control Program-and requested
an EPA review of an emission control system which they had
developed. A meeting was held between Echlin representatives
and T$EB personnel on May 30, 1972, to discuss the system
and the possibility of EPA testing. The system used what
Echlin representatives termed "...an important scientific advance
in the field of sonic energy". In further describing the
properties of their "ultrasonic generator" the Echlin
representatives reported:
"The new combustion environment created permits setting
the spark timing at nominal top-dead-center and management
of the fuel mass and ignition timing is such as to maintain
essentially stoichiometric combustion throughout all the
driving modes. This is accomplished without the temperature
anamolies and performance deterioration usually accompanying
these engine parameter adjustments, in the absence of the
Echlin system."
!
At the meeting Echlin presented emission data which had
been generated by Scott Research Laboratories. Emission levels
with and without the "ultrasonic generator" had been determined.
The data showed no emission reduction due to the "ultrasonic
generator." Echlin representatives admitted that the data did
not show a clear emissions benefit but that there was a fuel
economy benefit with the Echlin system as opposed to the fuel
economy loss normally associated with vacuum spark advance
disconnect (VSAD). Echlin also reported that the engine ran
significantly cooler with the Echlin system but the Scott data
did not consistently support this claim.
At the conclusions of the meeting T§EB personnel agreed to
run a series of tests on one of our vehicles used for device
evaluation.
System Tested
The complete Echlin system consists of:
1. An "ultrasonic generator"
2. A carburetor spacer plate
3. Tubing, which connects the generator to the
carburetor spacer plate
4. Gaskets necessary for carburetor removal and
replacement
In addition to the installation of this hardware, Echlin
recommended that the spark timing be retarded to 2? BTDC, the
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When the "ultrasonic generator" was disconnected the hose
which bled air to the spacer plate was clamped partially shut
until the idle CO level was the same (21) as when the "generator"
was hooked up. The air bleed flow characteristics were
undoubtedly different through the partially clamped hose than they
were through the generator device but the effects were similar.
In this configuration hydrocarbons were slightly reduced from
the baseline (5,1%), carbon monoxide was significantly increased
(57.31) and oxides of nitrogen were significantly decreased
(49.3%). There was no fuel economy penalty measured. The plots
of water temperature vs. time with and without the "ultrasonic
generator" were identical. When the Echlin system was removed
from the vehicle another series of tests were run with 2% idle
CO, 2° BTDC timing and vacuum spark advance disconnect. In
this configuration hydrocarbons were reduced from the baseline
by 22.71. Carbon monoxide increased by 23.5% and oxides of
nitrogen were reduced by 60.4%. A 5.4% fuel economy improvement
was measured.
No adverse driveability was noticed in any of the four
configurations during the testing.
Conclusions •
— .•-——•.-...-..- 11 i ^
1. The Echlin system significantly reduced oxides of
nitrogen emissions and significantly increased CO
emissions on the vehicle tested.
2. The emission reductions of a vehicle using the Echlin
system are due to vacuum spark advance disconnect (VSAD).
The Echlin hardware itself has no significant effect
on exhaust emissions. Our series of tests indicated
that calibrating a vehicle to 2% idle CO,setting timing
to 2° BTDC and eliminating vacuum spark advance results
in lower emission levels and improved fuel economy than
retrofitting the same vehicle with the Echlin system.
3. The "ultrasonic generator" of the Echlin system did not
improve fuel economy or reduce water temperature.
4. The Echlin system may cause durability and emission
problems on some vehicles because there is no provision
for restoring spark advance when engine temperatures
are high.
5. The addition of the carburetor spacer plate may cause
problems on some vehicles. On our test car the intake
air preheater had to be modified because it was no longer
sealed when the Echlin spacer plate was installed. Car-
buretor linkages may need modification or adjustment on
some vehicles.
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TABLE I
Summary of Echlin Device Testing
1975 Federal Test Procedure
Call data in grams per mile)
Baseline, 1963 Ford
Echlin System
Test
Number
18-0428
18-0432
18-0436
Average
12-2300
12-2302
12-2303
Average
HC
6.73
6.40
6.14
6.42
5.20
5.41
5.00
5.20
CO
59.93
56.97
55.09
57.3
78.67
80.76
79.78
79.74
NOx
5. "48
5.94
5.38
5.6
3.19
3.38
3.10
3.22
Calculated
MPG.
13.3
12.72
12.96
13.0
11.87
11.94
12.12
11.9
Change from Baseline
-19% +39.2% -42.5!
-8.5!
Vacuum spark advance 12-2386
disconnected, air 12-2389
bleed Average
Change from Baseline
6.35 93.11 2.88 12.64
5.84 87.15 2.80 13.62
6.09 90.13 2.84 13.10
-5.1% +57.3% -49.3% +.8%
Vacuum spark advance 16-0001
disconnected, -2% idle 12-2412
CO, no Echlin com- Average
ponents
Change from Baseline
4.88 67.59 1.90 13.67
5.03 73.91 2.54 13.70
4.96 70.75 2.22 13.70
-22.7% +23.5% -60.4% +5.4%
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APPENDIX I
FEDERAL EMISSION TESTING PROCEDURES
FOR LIGHT DUTY VEHICLES
The Federal procedures for emission testing of light
duty vehicles involves operating the vehicle on a chassis
dynamometer to simulate a 7.5 mile (1972 procedure) or
11.1 mile (1975 procedure) drive through an urban area.
The cycle is primarily made up of stop and go driving and
includes some operation at speeds up to 57 mph. The
average vehicle speed is approximately 20 mph. Both the
1972 and 1975 procedures capture the emissions generated
during a "cold start" (12-hour soak @ 68°F to 86°F before
start-up). The 1975 procedure also includes a "hot start"
after a ten minute shut-down following the first 7.5 miles
of driving.
Vehicle exhaust is drawn through a constant volume
sampler (CVS) during the test. The CVS dilutes the vehicle's
exhaust to a known constant volume with make up air. A
continuous sample of the diluted exhaust is pumped into
sample bags during the test.
Analysis of the diluted exhaust collected in the sample
bags is used to determine the mass of vehicle emissions per
mile of operation (grams per mile). A flame ionization de-
tector (FID) is used to measure unburned hydrocarbon (HC)
concentrations. Non-dispersive infrared (NDIR) analyzers are
used to measure carbon monoxide (CO) and carbon dioxide (C02).
A chemiluminescence (CL) analyzer is used to determine oxides
of nitrogen (NOx) levels.
These procedures are used for all motor vehicles designed
primarily for transportation of property and rated at 6,000
pounds GVW or less, or designed primarily for transportation of
persons and having a capacity of twelve persons or less. Each
new light duty vehicle sold in the United States in model years
1973 and 1974 must emit no more than 3.4 gpm HC, 39. gpm CO
and 3.0 gpm NOx when using the 1972 procedure. In 1975 the
standards will change to .41 gpm HC. 3.4 gpm CO and 3.1 gpm NOx
using the 1975 procedure. In 1976 the standards will be .41
gpm HC, 3.4 gpm CO and .4 gpm NOx using the 1975 procedure.
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