This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Emissions and Performance of a Small L-Head Utility Engine Fueled with Homogeneous Propane/Air and Propane/Air/Nitrogen Mixture
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 01, 1993 by SAE International in United States
Annotation ability available
The objective of this study was to observe and attempt to understand the effects of equivalence ratio and simulated exhaust gas recirculation (EGR) on the exhaust emissions and performance of a L-head single cylinder utility engine. In order to isolate these effects and limit the confounding influences caused by poor fuel mixture preparation and/or vaporization produced by the carburetor/intake port combination, the engine was operated on a premixed propane/air mixture. To simulate the effects of EGR, a homogeneous mixture of propane, air, and nitrogen was used. Engine measurements were obtained at the operating conditions specified by the California Air Resources Board (CARB) Raw Gas Method Test Procedure.
Measurements included exhaust emissions levels of HC, CO, and NOx, and engine pressure data. Analysis of the pressure data included IMEP determination, heat-release analysis, and determination of the characteristics of the cycle-to-cycle variations and interactions, for all operating modes of the CARB RGM test cycle for small utility engines.
Results indicate that the performance and emissions of the engine were strongly influenced by both air-fuel ratio and amount of N2 dilution. The HC emissions reached a minimum at approximately an equivalence ratio of 0.8, CO emissions began to increase at an equivalence ratio, Φ, of 0.95, and NOx peaked just lean of stoichiometric. Peak burn rates were observed at slightly rich of stoichiometric. Addition of simulated EGR reduced NOx emissions approximately 50 percent at a given equivalence ratio. However, fixed ignition timing limited the engine performance under lean conditions and with simulated EGR. Cyclic variation in the burn rate increased at some operating conditions with the lean equivalence ratios, and two burn modes were observed. However, prior cycle effects were not observed, indicating these variations are probably a result of same-cycle-processes.
CitationAngelo, T., Martin, J., and Borman, G., "Emissions and Performance of a Small L-Head Utility Engine Fueled with Homogeneous Propane/Air and Propane/Air/Nitrogen Mixture," SAE Technical Paper 932444, 1993, https://doi.org/10.4271/932444.
- “Notice of Public Hearing to Consider Regulations Regarding the California Exhaust Emissions Standards and Test Procedures for 1994 and Subsequent Model Year Utility and Lawn and Garden Equipment Engines,” California Air Resources Board, Mail-Out #90-64, October 16, 1990.
- “California Exhaust Emissions Standards and Test Procedures for 1994 and Subsequent Model Year Utility and Lawn and Garden Engines,” State of California Air Resources Board, December 14, 1990.
- Hare, C.T., Springer, K.J., Oliver, W.R., and Houtman, W.H., “Small Engine Emissions & Their Impact,” SAE Paper 730859, 1973.
- Donahue, J.A., Hardwick, G.C., Newhall, H.K., Sanvordenker, K.S., and Woelffer, N.C., “Small Engine Exhaust Emissions and Air Quality in the United States,” SAE Paper 721098, 1972.
- Hare, C.T., and White, J.J., “A Next-Generation Emission Test Procedure for Small Utility Engines - Part 1, Background and Approach,” SAE Paper 901595, 1990.
- White, J.J., Carroll, J.N., Hare, C.T., and Lourenco, J.G., “Emission Factors for Small Utility Engines,” SAE Paper 910560, 1991.
- Burrahm, R.W., White, J.J., and Carroll, J.N., “Small Utility Engine Emissions Reductions Using Automotive Technology,” SAE Paper 911805, 1991.
- White, J.J., Carroll, J.N., Hare, C.T., and Lourenco, J.G., “Emission Control Strategies for Small Utility Engines,” SAE Paper 911807, 1991.
- Quader, A.A., “Why Intake Charge Dilution Decreases Nitric Oxide Emission from Spark-Ignited engines,” SAE Paper 710009, 1971.
- “Test Procedure for the Measurement of Exhaust Emissions from Small Utility Engines - SAE Recommended Practice J1088 JUN83,” Society of Automotive Engineers, June 1983.
- Moore, W., “Temperature Measurement Techniques for Evaluation of Material Specimens in an Engine Cylinder,” M.S. Thesis, Mechanical Engineering Department, University of Wisconsin- Madison, 1990.
- Spindt, R.S., “Air-Fuel Ratios from Exhaust Gas Analysis,” SAE Paper 650507, 1965.
- Lancaster, D.R., Krieger R.B., and Lienesch, J.H., “Measurements and Analysis of Engine Pressure Data,” SAE Paper 750026, 1975.
- Martin, J.K., Plee, S.L., and Remboski, D.J., “Burn Modes and Prior Cycles Effects on Cyclic Variations in Lean-Burn Spark-Ignition Engines,” SAE Paper 880201, 1988.
- Matekunas, F.A., “Modes and Measures of Cyclic Combustion Variability,” SAE Paper 830337, 1983.
- Krieger, R.B., and Borman, G.L., “The Computation of Apparent Heat Release for Internal Combustion Engines,” ASME Paper 66-WA/DGP-4, 1966.
- Woschni, G., “A Universally Applicable Equation for the Instantaneous Heat Transfer Coefficient in the Internal Combustion Engine,” SAE Paper 670931, 1967.
- Caton, J.A., “Comparisons of Thermocouple, Time-Averaged and Mass Averaged Exhaust Gas Temperatures for a Spark-Ignited Engine,” SAE Paper 820050, 1982.
- Tabaczynski, R.J., Heywood, J.B., and Keck, J.C., “Time-Resolved Measurements of Hydrocarbon Mass Flowrate in the Exhaust of a Spark-Ignition Engine,” SAE Paper 720112, 1972.
- Personal Communication, Art Poehlman, Briggs & Stratton Corporation, Milwaukee, WI, Fall 1991 and Winter 1992.
- Ferguson, C.R., Internal Combustion Engines Applied Thermosciences, J. Wiley and Sons, New York, 1986.
- Wentworth, J.T., “The Piston Crevice Volume Effect on Exhaust Hydrocarbon Emission,” Combustion Science and Technology, vol. 4, pp. 97-100, 1971.
- Young M.B., “Cyclic Dispersion in the Homogeneous-Charge Spark-Ignition Engine - A Literature Survey,” SAE Paper 810020, 1981.
- Sztenderowicz, M.L., and Heywood, J.B., “Cycle-to-Cycle IMEP Fluctuations in a Stoichiometrically-Fueled S.I. Engine at Low Speed and Load,” SAE Paper 902143, 1990.
- Sztenderowicz, M.L., and Heywood, J.B., “Mixture Nonuniformity Effects on S.I. Engine Combustion Variability,” SAE Paper 902142, 1990.