In this paper, a control-oriented model of a medium-duty throttle-body natural gas engine is developed. The natural gas engine uses lean-burn technology without exhaust gas recirculation (EGR). The dynamic engine model differs from models of gasoline engines by including the natural gas fuel dynamics in the intake manifold. The model is based on a mean value concept and has three state variables: intake manifold pressure, fuel fraction in the intake manifold and the engine rotational speed. The resulting model has been validated in steady-state and transient operation over the usual operating range of the engine between 800 rpm and 2600 rpm with air/fuel ratios ranging between 18.0 and 24.0.
Issue Section:
Technical Papers
1.
Hundleby, G. E, 1989, “Low Emission Approaches for Heavy-duty Gas Powered Urban Vehicles,” SAE paper no. 892134.
2.
Nakagawa K., Okamoto K., and Shoji Fujio, 1994, “Development of an Air/fuel ratio control system for lean burn gas engines,” SAE paper no. 942041.
3.
Hendricks, E. and Sorenson, S. C., 1990, “Mean Value Modelling of Spark Ignition Engines,” SAE technical paper 900616, pp. 1–15.
4.
Moskwa
, J. J.
, and Hedrick
, J. K.
, 1992
, “Modeling and Validation of Automotive Engines for Control Algorithm Development
,” ASME J. Dyn. Syst., Meas., Control
, 114
, June, pp. 278
–285
.5.
Dobner, D. J. and Fruechte, R. D., 1983, “An Engine Model for Dynamic Engine Control Development,” Proceedings of the American Control Conference, San Francisco, CA, June, pp. 73–78.
6.
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7.
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8.
Heywood, J. B., 1988, Internal combustion engine fundamentals, McGrawHill, NY.
Copyright © 2001
by ASME
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