74-34 AW
An Evaluation of the Hydrocatalyst Corporation's
Pre-combustion Catalyst Emission Control Device
June 1974
Technology Assessment and Evaluation Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Environmental Protection Agency
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Background
The Environmental Protection Agency receives information about many
devices for which emission reduction or fuel economy improvement
claims are made. In some cases, both claims are made for a single
device. In most cases, these devices are being recommended or promoted
for retrofit to existing vehicles.
The EPA is interested in evaluating the validity of the claims for
all such devices, because of the obvious benefits to the Nation of
identifying devices that live up to their claims. For that reason
the EPA invites proponents of such devices to provide to the EPA
complete technical data on the device's principle of operation,
together with test data on the device made by independent laboratories.
In those cases in which review by EPA technical staff suggests that
the data submitted holds promise of confirming the claims made for
the device, confirmatory tests of the. device are scheduled at the EPA
Emissions Laboratory at Ann Arbor, Michigan. The results of all such
confirmatory test projects are set forth in a series of Technology
Assessment and Evaluation Branch Reports, of which this report is
one.
The conclusions drawn from the EPA confirmatory tests are necessarily
of limited applicability. A complete evaluation of the effectiveness
of a retrofit device in achieving its claimed performance improvements
on the many different types of vehicles that are in actual use requires
a much larger sample of test vehicles than is economically feasible in
the confirmatory test projects conducted by EPA. For promising devices
it is necessary that more extensive test programs be carried out.
The conclusions from the EPA confirmatory tests can be considered to be
quantitatively valid only for the specific type of vehicle used in the
EPA confirmatory test program. Although it is reasonable to extrapolate
the results from the EPA confirmatory test to other types of vehicles
in a directional or qualitative manner, i.e., to suggest that similar
results are likely to be achieved on other types of vehicles, tests of
the device on such other vehicles would be required to reliably quantify
results on other types of vehicles.
In summary, a device that lives up to its claims in the EPA confirmatory
test must be further tested according to protocols described in footnote l/»
to quantify its beneficial effects on a broad range of vehicles. A device
which when tested by EPA does not meet the claimed results would not appear
I/ See Federal Register 38 FR 11334, 3/27/74, for a description of the
test protocols proposed for definitive evaluations of the effectiveness
of retrofit devices.
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to be a worthwhile- candidate for such further testing from the standpoint
of the liklihood of ultimately validating claims made. However, a definitive,
quantitative evaluation of its effectiveness on a broad range of vehicle
types would equally require further testing in accordance with footnote —'.
The Hydrocatalyst Corporation produces a device called the Pre-combustion
Catalyst which is purportedly designed to reduce emissions from internal
combustion engines. The Pre-combustion Catalyst consists of two plated
screens (see device description below) suspended in the intake flow.
It is claimed that the two screens have a catalytic effect on the
air/fuel mixture which influences combustion in such a manner as to
lower hydrocarbon, carbon monoxide and oxides of nitrogen emissions.
In addition, it is claimed that the octane requirement of the engine
is lowered.
The device was previously tested by the EPA and reported on in July 1973
(report #74-4). At that time, no baseline tests were run on the test
vehicle (with the Hydrocatalyst device not installed), so it was not
possible to compare the vehicle emissions before and after the installation
of the device. The conclusions of that report were that no significant
control of hydrocarbons or oxides of nitrogen was demonstrated (compared
to typical certification results) and that the low levels of carbon
monoxide achieved during the test program were probably a function of
choke setting. In addition, minimal choke action led to poor cold start
driveability.
Because of a lack of baseline testing during the initial test program,
a re-evaluation of the device was scheduled to further investigate the
effect on emissions attributable to the Hydrocatalyst device.
Device and Test Vehicle Description
The Hydrocatalyst device consists of a bowl-shaped, dual-screened element
which is fixed in the intake manifold. The screen element is made of a
pair of screens of a planar configuration spaced about 1/16" apart. One
screen is plated with cadmium and the other with nickel. The element is
made as an integral part of the intake manifold/carburetor gasket and is
suspended in the flow stream of the intake manifold/carburetor interface.
In the literature supplied with the device, it was claimed that a catalytic
effect on the air/fuel mixture causes and/or initiates precursors that
influence combustion. It was claimed that this precursory effect lowered
vehicle octane requirement and allowed for more tolerance to lean carburetion,
thus achieving ja reduction in emissions.
The test vehicle was a 1970 Valiant with a 225 CID engine. The car was
equipped with an automatic transmission. At the start of the evaluation
progran the test vehicle was given a complete tune-up to manufacturer's
specifications. Vehicle mileage at the tune-up was 14,300 miles. Since
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the test vehicle had been run on a variety of fuels in past test
programs, it was run-in after the tune-up for 500 miles on the Dura-
bility Driving Schedule described in the Federal Register (Vol. 37,
No. 221, November 15, 1972), with leaded fuel (used throughout this
program) to stabilize combustion chamber deposits.
Test Program
All tests were run as directed in the 1975 Federal Test Procedure (FTP)
Federal Register, November 15, 1972, Vol. 37, No. 221, Part II. The
following sequence of tests wa» performed:
1. After the tune-up to manufacturer's specifications and the 500-mile
running-in, baseline emissions tests were run with the car adjusted to
manufacturer's specifications.
2. After completion of the baseline emissions tests, the parameter
adjustments recommended in the Hydrocatalyst installation instructions
were made to the car. These adjustments consisted of advancing the
timing 6 degrees beyond manufacturer's specifications and leaning the
idle mixture to a setting just richer than misfire. Several emissions
tests were run on the vehicle with these parameter adjustments.
3. After testing the vehicle with parameter adjustments, the Hydro-
catalyst device was installed. After the device was installed, the
mixture was again leaned to the point just richer than misfire. Several
emissions tests were run on the vehicle after device installation.
A. Since the installation instructions indicated that the effectiveness
of the device improves with time after installation, 1500 miles were
accumulated on the vehicle using the same durability driving schedule
that was used for the baseline running-in. Several tests were run on
the vehicle after completion of the mileage accumulation.
5. The idle mixture was then readjusted to the point just before
misfire and two more emissions tests were run. This condition represented
the best adjustment for emissions with the device installed on the vehicle.
6. The device was then removed from the vehicle and two more emissions
tests were run. No changes in engine parameters were made from step 5.
7. Finally, the vehicle was reset to manufacturer's specifications and
a second series of baseline emissions tests were run. The purpose of the
final baseline tests was to determine if there had been any change in
exhaust emissions attributable to cleaning of combustion chamber deposits
during the time the device was on the vehicle.
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Hydrocatalyst personnel were invited to observe the entire test program.
They elected to view the device installation and vehicle adjustments made
in steps 5, 6 and 7, as well as the accompanying testing (except in step 7
where only the adjustments were observed).
Test Results
Exhaust emissions data in grams per mile and fuel economy calculated by
the carbon balance method-are presented in Table I.
Initial testing after installation of the Hydrocatalyst device (step 3)
showed a 26% increase In HC, a 73Z increase in CO, no change in NOx,
and a 4% decrease in fuel economy compared to the baseline results.
After the 1500-mile accumulation (step 4), there was a 15% increase in
HC, a 93% increase in CO, a 2% increase in NOx, and an 11% decrease in
fuol economy compared to baseline. Further enleanment of the mixture
(step 5) resulted in a 24% HC increase', a 53% CO increase, an 8% NOx
increase and an 8% decrease in fuel economy compared to baseline.
Final baseline emissions (step 7) were about the same as the original
baseline emissions.
Oriveability of the test vehicle was unaffected by installation of the
Hydrocatalyst device.
Conclusions
Use of the Hydrocatalyst device on this test vehicle proved to be
detrimental to both emissions and fuel economy. The large increases
over baseline of carbon monoxide and hydrocarbons suggest that the
engine was running at a richer air/fuel ratio with the catalyst in-
stalled. A possible explanation for this apparent richening of the
mixture is that the screens, for which catalytic action is claimed,
choked the carburetor- throat to the extent that the secondary power
circuit was coming into use (the power valve senses manifold vacuum).
The data from steps 3,4 and 5 show that the Hydrocatalyst device had
no significant effect on NOx emissions. The large NOx increases seen
in steps 2-and 6 were caused by the parameter adjustments, i.e,, ig-
nition timing advance and idle mixture enleanment.
Final baseline emissions showed no evidence of combustion chamber cleaning
due to use of the Hydrocatalyst device. Had there been a cleaning of com-
bustion chamber deposits during the test program, then HC emissions in
step 7 would be significantly lower than in step 1. Since HC emissions in
step 7 were not significantly lower than in step 1, it is concluded that
the cleaning did not occur.
The change in baseline NOx emissions (a 15% increase in step 7 compared
co step 1) is not considered significant, when factors such as the
accumulation of 1500 miles and test-to-test variability are taken into
account.
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Table I
Evaluation of llydrocatnlyst Device
on a 1970 Valiant with a 225 CIO, 6-Cylindcr Enaine
Mass Emissions In grams per mile and Fuel Economy in miles per gallon
197S Federal Test Procedure
Test Step;
1.
2.
3.
4.
S.
6.
7.
HC
Baseline 2.ZO
1.87
1.98
AVERAGE 2.02
Engine Parameter Changes
2. OS
2.05
1.97
AVERAGE 2.02
\ Change from
Baseline
0
HyJrocatalys t device
installed, before mileage
accumulation
2.37
2.71
AVERAGE 2.54
t cfhange from
Baseline
»26»
iljrdrocntalyst device
installed, after mileage
accumulation
2. 25
2.38
AVERAGE 2'32
I Change from
Baseline
»isi
CO
30.9
23.8
24.4
26.4
20.7
20.6
22.2
21.2
-201
43.6
47.7
45.7
»73»
52.1
49.7
50.9
+ 93»
co2
421
410
408
413
406
408
403
406
-2t
393
389
391
-51
420
428
429
+3t
NOX
...
5.08
4.35
4.72
5.44
6.32
6.01
5.92
+ 2St
4.65
4.83
4.74
0
4.77
4.86
4.82
*2»
MPG
18.2
19.2
19.3
18.9
19.4
19.4
19.4
19.4
*3\
18.2
17.9
18.1
-41
16.9
16.7
16.8
-111
Hydrocatalyst device installed.
after mileage accumulation
enleanment
2.37
2.63
AVERAGE 2.50
f Change from
Baseline
+ 24*
41.1
42.1
41.6
*S8t
421
425
423
»2»
4.90
5.31
S.ll
»8l
17.4
17.3
17.4
-81
Hydrocatalyst device removed,
no parameter changes
1.74
1.69
AVERAGE 1.72
% Change from
Baseline -15%
, Final Baseline
2.01
2.14
AVERAGE 2.08
\ Change from
Baseline
16.7
17.4
17.1
-35%
27.9
26.6
27.3
427
421
424
+3%
410
426
418
6.48
6.31
6.40
+361
5.17
5.65
5.41
19.1
19.3
19.2
42%
18.8
18.4
18.6
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ADDENDUM TO HYDRO-CATALYST REPORT
Subsequent to the publication of the EPA test report
on the Hydro-Catalyst device, EPA was notified by Hydro-
Catalyst that the unit intended for use on Chrysler Corpora-
tion 225 CID engines:has been redesigned. The mounting
flanqe on that unit has been changed to allow venting of the
carburetor and avoidance of carburetor enrichment.
Data reported by Hydro-Catalyst support their claim
that the redesign avoids the carburetor enrichment problem,
but do not show significant reduction in exhaust emissions.
EPA has not tested the redesigned unit.
* MS. GOVERNMENT PRINTING OFFICE: 1979- 651-112/0120
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