PROGRESS REPORT NO, 13 KINETICS OF OXIDATION AND QUENCHING OF COMBUSTIBLES IN EXHAUST SYSTEMS OF G-ASOLINE ENGIINES D. J. PATTEIS )N PERIOD: March 1, 1970 to March 51., 1970 Malrch 197) This project is -:.tder the techni. cal. supervision of the: Coordi-diat.ig Research Council APRAC-Cape 8-68 Steerilg Comm:i.ttee and is work perfor<)-med by the: Department of Mechanical Eng-ineerinlg The University of Michigan Ann Arbor, Michigan Under ConLtract No. CAPE-8-68(1-68)-CRC and Conatract No, CPA-22-69-51.-HEW

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 Chevron Research Company 576 Standard Avenue Richmond, California 94802 Mr. R. L. Bradow, Senior Chemist Research and Technical Department Texaco, Inc. P. O. 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 1 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 2053 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

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 montho PHASE I PROGRESS Baseline evaluation of the 350 CID Chevrolet engine has beern completed. It is felt that adequate data on the effect of speed, load, timing, and mixture rati.o have been gathered. Moreover with the completion of the hydrogen meter,

the process instrumentation development has been virtually finalized. Figure 1 shows a curve of corrected dry hydrogen as measured by our thermal conductivity meter versus measured dry CO. Data taken on two days is shown. Indolene fuel of approximately CH1.86 was used. Plotted for comparison are theoretical curves for CH and CH from D'Alleva. D'Alleva assumed the 2.00 1. 75 water-gas reaction with'K' equal to 3.8. The greater than theoretical amount of hydrogen near chemically correct probably results from cycle-to-cycle and cylinder-to-cylinder mal-distribution. Similar behavior of CO and 02 is common. At this time we have no explanation for the low H2 readings (compared to D'Alleva) at high % CO. NO readings were not obtained for Run 1. Therefore the NO correction was estimated. Experience with the hydrogen meter to date suggests that other exhaust gas constituents do interfere with the H2 readings. These interferences are summarized in Table I. The most serious interference measured was that of NO. 1%o NO appears to the meter as.5% H2. This interference is most troublesome near chemically correct mixtures where H2 is small and NO is approaching a maximum. The large NO interference has not been explained yet. The CO interference is the next largest and is in fact relatively small. It tends to be a constant percentage correction because of the water-gas equilibrium situation prevalent in exhaust gas. At 1Co CO where hydrogen concentration is about 5% the CO correction adds about.25% hydrogen to the measurement, an interference of 5%. CO2 and water vapor have large responses and are therefore removed prior to D'Alleva, B. A. "Procedure and Charts for Estimating Exhaust Gas Quantities and Compositions," GM Research Report 372, 1960.

Fueol UCH,|6 -x An / (NOx Est) Fuel, C/// 86 Run 2 8' D'ALLEVA CH2 Low High ~~~~~%H26~" l Range Range CH 4.75 %H2 6 OX 0 2 4 6 8 10 12 14 16 %0CO Figure 1. % H2 versus % CO. Solid lines are theoretical values from D'Alleva, Reference 1. 350 CID V-8 1200 rpm, 50%o FL, MBT spark.

measurement. The final hydrogen values are corrected to a dry basis containing C02, the same basis upon which the other constituents are reported. The next step in Phase 1 is to install the du Pont reactors. TABLE I RESPONSE OF HYDROGEN METER TO EXHAUST GAS CONSTITUENTS Laboratory Gas Meter Reading, Constituent X Concentration, M m % H2/% X % X in N2 H2 4. 1 8.20 (set point) 1.00 02 21.0 (air).42.01 CO 5. o.25.025 NO O0.3 3.5 N2 100.o0 0 0 HC.072 (720 ppm hexane) 0 0 CO2 removed - - H20 removed --- - - PHASE II PROGRESS Attempts to apply the stirred tank reactor model developed earlier to higher levels of exhaust gas combustibles (represented by approximately 8% CO, 4% H2 and 500 ppm CH4) met with computational difficulties due to "chattering" as the conversions approached unity. In particular, the computed concentrations for oxygen and oxidation products (water and carbon dioxide) were found to increase without bound due to extents of reaction over one computational step that proceeded to large negative values of the combustibles rather than approaching zero as desired. Unrealistically high temperatures also resulted. Efforts are being made to correct the instability in the model without

its flexibility in handling cyclic input. Corrections have been added to offset negative extents of oxidation reaction, and in the case of carbon monoxide the reverse reaction has been added. Work on this aspect of the program will continue. During the following month regression routines will be investigated to obtain a program well suited to treatment of kinetic data from the two-tank experimental reactor. PHASE III PROGRESS A man has been engaged to continue the gas chromatographic work. The twotank reactor has been received from Walker Manufacturing Company. Next this reactor will be installed on a single cylinder engine.

OVERALL FINANCIAL SUMMARY Program Total: February 24, 1969 - February 23, 1970 $106,455 Cumulative Expenditures through February 23, 1970 106,569 Balance $ (114i 110 100 Labor - - - Projected A — * Actual Total * Projected -Actual 90 80 Labor 70 Incl. Post Doctoral — ~ Fellowship Dollars Thousands _40 - -, 30. / rMo M LA 1 u Months 19E9 1970