PROGRESS REPORT NO. 14 KINETICS OF OXIDATION AND QUENCHING OF COMBUSTIBLES IN EXHAUST SYSTEMS OF GASOLINE ENGINES D. J. PATTERSON PERIOD: APRIL 1, 1970 to APRIL 30, 1970 April 1970 This project is under the technical supervision of the: Coordinating Research Council APRAC-CAPE 8-68 Steering Committee and is work performed by the: Department of Mechanical Engineering The University of Michigan Ann Arbor, Michigan Under Contract No. CAPE-8-68 (1-68)-CRC and Contract No. CPA-22-69-61-HEW

LONG-RANGE OBJECTIVES It is well-known that a significant amount of CO and unburned fuel may be consumed in the exhaust system of gasoline engines. Such combustion phenomena in exhaust reactors may be used to advantage to reduce the emission of these undesirable constituents. This process is the basis of exhaust air injection systems currently installed on some automobiles. The overall objectives of this three-year research program are: To determine the chemical and physical processes which affect the emission characteristics of exhaust reactors installed on selected typical engines operating at various conditions on a dynamometer test stand. * To identify the chemical species and significant chemical reactions present before, within, and after the reactor. * To obtain information which will be helpful in predicting the design of the next generation of gasoline engine exhaust reactors. GENERAL A contract has not been executed for the second year at this writing. It is hoped that a contract can be negotiated next month. PHASE I PROGRESS Analysis of baseline data on the 350 CID has revealed some inconsistencies in the data. Exhaust air-fuel ratio calculated by the method of Spindt does not agree well with measured air-fuel ratios. In some cases deviations of one air-fuel ratio have been noted. Carbon monoxide and oxygen readings appear to

follow consistently the exhaust air-fuel ratio. Before the duPont reactors are installed it is felt that a thorough check of the air-fuel and exhaust gas measuring systems must be made. Some repeat runs are in order which should require only a few days. The duPont reactors will then be installed. PHASE II PROGRESS Work involving the applications of the stirred tank reactor model to higher levels of exhaust gas combustibles has continued. The computational difficulties encountered as the conversion of carbon monoxide approached unity have been remedied. Corrections were added to offset the negative extents of reaction. The addition of reverse reactions as suggested in the March report proved unnecessary. At the present time the stirred tank reactor model does not predict the correct steady state for conversions of 20% or less for the higher levels of exhaust gas combustibles. In particular the resulting temperature is considerably lower than that predicted from the resulting conversions. Efforts are being made to correct this inconsistency. Finally, steps are being taken to modify an already existing statistical regression program which will analyze the kinetic data obtained from the twotank experimental reactor. Work during the following month will continue on the exhaust reactor model for low conversions of combustibles as well as on the regression program.

PHASE III PROGRESS Further work on the gas chromatograph should begin next month following completion of the final examination period. The verification of the subtractive analyzer has top priority. Some slight modifications have been made to the two-tank reactor system prior to its installation on the single cylinder engine. In particular, a leakage path through which injected air could directly enter the reactor without mixing has been sealed. A back pressure throttled valve has been fabricated. Installation will be completed next month. At this time, a major effort is being devoted to getting the two-tank system operational. This is because kinetic data is needed immediately for the math model. Three of the four students who have been working on the multicylinder engine will devote their time as required to the two-tank reactor. On the average this means a temporary 25% reduction of effort on the multicylinder engine, Phase I. Good progress has been made on the laser-schlieren system for measuring exhaust temperature and velocity. The equipment is all installed. Some poor quality photographs have been obtained. Next a better alignment of the optical system will be made and a technique developed to synchronize the drum camera with the engine cycle events.

CRC CAPE 8-68 PROGRAM OVERALL FINANCIAL SUMMARY Program Total: February 24, 1970 - February 23, 1971 $106,500 Cumulative Expenditures through March, 1970 10,664 Balance $ 95,836 110 T 100 Labor -— Projected x —x Actual Total -Projected -Actual 90 80 70 Dollars6 50 40 / 30 0*01 20 10 / 0 F M A M J JU A S 0 N D d F M Months 1970 1971

DISTRIBUTION LIST No. of' Contract Distribution copies Mr. Alan E. Zengel 3 Assistant Project Manager Coordinating Research Council, Inc. 30 Rockefeller Plaza New York, New York 10020 Dr. P. R. Ryason 1 Chevron Research Company 576 Standard Avenue Richmond, California 94802 Mr. R. L. Bradow, Senior Chemist Research and Technical Department Texaco, Inc. P. 0. Box 509 Beacon, New York 12508 Dr. E. N. Cantwell Automotive Emissions Division Petroleum Laboratory E. I. DuPont de Nemours and Company, Inc. Wilmington, Delaware 19898 Dr. J. B. Edwards Research Section Chrysler Corporation 12800 Oakland Avenue Detroit, Michigan 48203 Mr. G. D. Kittredge 15 Motor Vehicle Research and Development Bell Tower Hotel 300 South Thayer Street Ann Arbor, Michigan 48104 Dr. H. Niki Scientific Laboratory Ford Motor Company P. 0. Box 2055 Dearborn, Michigan 48121

DISTRIBUTION LIST (Concluded) No. of Contract Distribution copies Mr. R. C. Schwing 2 Research Center Laboratories Fuels and Lubricants Department General Motors Corporation General Motors Technical Center 12 Mile and Mound Roads Warren, Michigan 48090 Mrs. Mary Englehart 1 Department of Health, Education, and Welfare National Air Pollution Control Administration 411 W. Chapel Hill Street Durham, North Carolina 27701 Internal Distribution Professor J. A. Bolt, Dept. of Mech. Eng., Auto. Lab., N.C. 1 Professor B. Carnahan, Dept. of Chem. Eng., East Eng. Bldg. 1 Professor J. A. Clark, Dept. of Mech. Eng., West Eng. Bldg. 1 Professor D. E. Cole, Dept. of Mech. Eng., Auto. Lab., N.C. 1 Professor N. A. Henein, Dept. of Mech. Eng., Auto. Lab., N.C. 1 Professor R. Kadlec, Dept. of Chem. Eng., East Eng. Bldg. 1 Professor H. Lord, Dept. of Mech. Eng., Auto. Lab., N.C. 1 Professor J. J. Martin, Dept. of Chem. Eng., East Eng. Bldg. 1 Professor W. Mirsky, Dept. of Mech. Eng., Auto. Lab., N.C. 1 Professor D. J. Patterson, Dept. of Mech. Eng., Auto. Lab., N.C. 2 Project File 14