PROGRESS REPORT NO. 9 KINETICS OF OXIDATION AND QUENCHING OF COMBUSTIBLES IN EXHAUST SYSTEMS OF GASOLINE ENGINES D. Jo PATTERSON PERIOD: NOVEMBER 1, 1969 to NOVEMBER 30, 1969 NOVEMBER 1969 This project is under the technical supervision of the: Coozrdinating Research Council APFAC-Cape 8-68 Steering Committee and is work performed by the: Department of Mechanical Engineering The University of Michigan Ann Arbor, Michigan Under, Contract Noo CAPE-8-68(1-68)-CRC and Conltract Noo CPA-22-69-51-JHEW

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 i. 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: o 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 stand0 To identify the chemical species and significant chemical reacticns pr esent before, within, and after the reactor0 o To obtain information which will be helpful in predicting the design of the next generation of gasoline engine exhaust reactors. PHASE I PROGRESS Addition_.al data were obtained on the effects of mixture ratio on emissions fr om the standard 350 CID V-8 engine0 Two additional instruments were added, the Beckman NDIR NO analyzer and the subtractive column analyzer. Figures 1-4 show a set of data for the engine at 50o full load, 1200 rpm, MBT spark. All readings at each air-fuel ratio were recorded approximately at the same timeo NG1 readings are not reported because a leak was found in the sampling system of the analyzer0 The leak has been corrected0 Tests shown were run with American. Regular fuelo ~~o 1-~~~~~~~~~~

Figure 1 shows the C02, CG, and 02 emission from the engine. Figure 2 shows the hydrocarbon emission measured by both FID and NDIR analyzers. The ratios of the readings are plotted also. Figure 3 shows a class analysis using the subtractive column analyzer. Our analyzer, patterned after that of Sigsby, reports olefins and acetylene together and includes a fraction of the benzene in the paraffin reading. This fraction appears to be about 6C0o as indicated in last monthVs progress report. A problem was found with the analyzer in that the columns became saturated quickly during engine tests. The missing and questionable data points on Figur-e 3 resulted from this problem. The problem appears to have resulted from a m'odification we made in the analyzer flow system. In our unit we monitor the back-flush with the FID. This gives us an indication of whether the nitrogen bactk-flush is effectiv'ely cleaning the columns. Unfortunately, this modification allowed exhaust gas to seep through the columns during the time that the analyzer was on standby and the FID was continuously monitoring the total hydrocarboos, A shut-off valve has been installed in the back-flush line to eliminate the problem. Aldehydes, as formaldehyde, measured by the DNPH method are shown also on Figure 30 Minimum aldehyde emission was in the range of 11 to 13:1 air-fuel ratio. Aldehyde emissions doubled at 1805:1. Some similarity exists between exhaust wye temperature change and aldehyde emission changes. Figure 4 shows the hydrocarbon class concentration as a percent of the total FID hydrocarbon readingo At present the level of confidence in these readings is low. Because reactivity depends primarily on the olefin concentrations, the data suggests

that for lean mixtures, reactivity may actually increase even when total hydrocarbons decrease. More baseline data will be obtained with *the subtractive column analyzer. Progress continues toward developing a laser schlieren system for simultaneously measuring exhaust gas temperature and velocity. An optical test section has been built for a single cylinder engine0 The NE-HE gas laser light tube needs replacing. The laser has been returned to Spectra-Physics for this repair. A design nears completion for a two tank single cylinder exhaust reactor system. This system is designed to obtain basic kinetic data similar to that of Richard Schwing, GM Research. Next, this exhaust reactor system will be fabricated. PHASE II PROGRESS The first generation model is being programmed on the IBM-360 computer. PHASE III PROGRESS Work continues to separate the lighter hydrocarbons using the PerkinElmer 800 gas chromatography

RUN 2A6 CO2.I I II 10 0 z 8 10 12 14 16 18 AIR-FUEL RATIO Figure 1. C02, CO, and 02 emission versus air-fuel ratio. 350 CID, V-8, 1200 rpm, 5f%o load, MBT spark, regular gasoline. 6-~~~~~~~

RUN 2A6 1400 1200 \\ 2.6 to IX XN6 0 0 < 1000 2.2 o C/) rZ 800 1.8 m F/V ~.( 600 0: 400 200 0 10 12 14 16 18 AIR-FUEL RATIO Figuire 2. Hydrocarbon emission versus air-fuel ratio. 350 CID, V-8, 1200 rpm, 5Oo load, MBT spark, regular gasoline.

1400 RUN 2A6300 1100 0 I Temperature IOOO 1000 1200 x 200 - 900 Aldehydes 1 >7 z w I V) w OOi" zIX 400 Figure 3. Hydrocarbon emission by classes and exhaust Wye temperature as a function of air-fuel ratio. Class analysis by subtractive column. DNPH aldehydes are indicated also. 350 CID, V-8, 1200 rpm, 502/ load, MBT spark, regular gasoline. Question marks indicate questionable data. gasoline. Question marks indicate questionable data.

~~100 -i — ~RUN 2A6 80 H 6 0 O/efins +Acety/ene C) LZ o~ 40-' 0 Poroffins 20 Arom akc $s 10 12 14 16 18 AIR-FUEL RATIO Figare 4. Hydrocarbon classes, percent, as a function of air-fuel ratio. Question marks indicate questionable data.

CRC CAPE 8-68 PROGRAM OVERALL FINANCIAL SUMMARY Program Total: February 24, 1969 - February 23, 1970 $106,455 Cumulative Expenditures through October 24, 1969 68,909 Balance $ 37,546 110 100 _ Labor - - - Projected * - ( Actual Total - Projected -' -Actual 90 80 70 60 Dollars // Thousands50 40 - -- 30 20 10 / ~F M A M J Ju A 0N D Months 1969 1970

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 1 Research and Technical Department Texaco, Inc. P. 0. Box 509 Beacon, New York 12508 Dr. E. N. Cantwell 1 Automotive Emissions Division Petroleum Laboratory F. 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 1 Scientific laboratory Ford Motor Company P. 0. Box 2053 Dearborn, Michigan 48121

DISTRIBUTION LIST (Concluded) No. of Contract Distribution copies Mr. R. C. Schwing 1 Research Center Laboratories Fuels and Lubricants Department General Motors Corporation Ceneral Motors Technical Center i2 Mile and Mound Roads Warren, Michigan 48090 Mrs. Mary Englehart 1 Department of Health, Education, and Welfare National Air Pollution Control Administration 41.1 W. Chapel Hill Street Durham, North Carolina 27701 Interia 1 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 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 15