72-3
An Evaluation of the Emissions Characteristics
of the Esso Well Mixed Thermal Reactor
August 1971
John C. Thomson
Office of Air Programs
ENVIRONMENTAL PROTECTION AGENCY
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Background
Esso Corporation recently announced the development of an
advanced emission control system for reciprocating engines.
It was offered to the Environmental Protection Agency for
evaluation.
Description
The vehicle tested was a 1971 Ford LTD with a special Esso
thermal reactor and the necessary modifications to the
vehicle for the operation of the reactor. The vehicle used
a 351 cubic inch V-8 and an automatic transmission. The
reactor is attached to the exhaust ports and replaces the
exhaust manifold. A combination of fuel rich carburetor,
exhaust gas recycle and spark retard are used to control
oxides of nitrogen (NOX) while carbon monoxide (CO) and
hydrocarbons (HC) are mixed and burned in the reactor with
secondary air supplied by an air pump. A special flame
holder allows the system to reach operating temperature in
less than 10 seconds. A complete description of the system
is available in the Society of Automotive Engineers paper
number 710608 presented in Montreal in June 1971.
Test Program
For the evaluation of this system, two test procedures were
used. The 1972 and 1975 Federal Emission Test Procedures
used for new vehicle certification were used. The 1972 test
procedure uses the constant volume sampling system (CVS) to
collect an exhaust sample during a 7-5 mile test conducted
on a chassis dynamometer. The test is begun after the vehicle
has soaked at room temperature for at least 12 hours. For
1975 tests basically the same driving cycle and sampling
techniques are used but a procedure for weighting the cold
portion has been added. This requires the exhaust to be
sampled three times during the test and the test is increased
to 11.1 miles. A complete description of the test procedures
is available in the July 2, 1971, Federal Register.
The exhaust gases were measured using a flame ionization
detector for HC, while CO and C02 were measured using infrared
techniques. A chemiluminescent instrument was used for NOx.
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Results
The results from the tests calculated according to the 1972
test procedure are reported in Table 1. For reference the
standards for 1972, 1973, and 1974 are also SDown in this
table. All results from this vehicle are well below the
emission standards required for new vehicles through 1974.
The results from two of the tests where the 1975 procedure
was used are reported in Table II. The standards for 1975
and 1976 are also shown in this table and the vehicle is
very close to meeting the 1975 standards. Meeting the 1976
standards with this vehicle will require further NOx reduction.
Results from other labs testing this system are shown in
Table III.
Conclusions
This system will meet all standards through ~974 and shows
promise for meeting the 1975 standards. In order to achieve
the 1976 standards, additional contro~s for NOx are required,
although it may be able to meet stand~rds in a lighter
vehicle.
The results from testing this vehicle at other labs shows
that consistent emission control is achieved and good
correlation between laboratories is possible with low emission
vehicles.
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TABLE
I
1972 Test Procedure
Esso Thermal Reactor
1971 Ford v-8 Automatic Transmission
!
(All results in grams per ~ile)
HC CO C02
Test Date (FID) (IR) (IR)
June 2, 1971 0.2 6 1019
. June 23, 1971 0.1 5 1103
June 24, 1971 0.1 5 1060
1972 Standards 3.4 39
1973- 7 4 Standards 3.4 .39
NOx
(CI)
0.6 .
0.6
0.6
3.0
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i
TABLE
II
1975 Test Procedure
Esso Thermal Reactor
1971 Ford v-8 Automatic Transmission
(All r.esults in grams per mile)
HC CO NOx
Test Date (FID) (IR) (CI)
June 23, 1971 0.11 4.76 0.67
June 24, 1971 0.10 3.19 0.67
1975 .Standards 0.41 3.4 3.1
1976 Standards 0.41 3.4 0.4
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TABLE III
Esso Data Comparisons
1972 Test procedure
!
(All results in grams.per~mile)
HC CO C02 NOx
Test Site (FID) (IR) (IR) eCI)
EPA #2 0.2 5.9 1019 0.65
Ford 0.2 5.6 0.65
GM 0.2 5.6 0.68
EPA #3 0.1 4.5 1080 0.62
EPA #4 0.2 3.8 1050 0.64
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