IDENTIFICATION OF A NONLINEAR INTERNAL-COMBUSTION ENGINE MODEL FOR ONLINE INDICATED TORQUE ESTIMATION

In recent years considerable interest has been placed on the estimation of internal combustion engine torque both for control and diagnostic applications. This paper discusses a method for the identification of a non-linear model of the dynamics relating combustion pressure to crankshaft angular velocity. Such a model can be useful in the implementation of control strategies that require an estimate of individual cylinder indicated torque or pressure--variables not easily measured directly with low-cost instrumentation, or in the development of advanced diagnostic strategies. The method demonstrated in this paper utilises a known model structure and employs non-linear programming for the identification of relevant model parameters. The technique is applied to a single cylinder research engine, and is successfully validated with experimental data. Finally, the model thus derived is used to design an input observer for the estimation of indicated torque. © 1994 Academic Press, Limited.