A mathematical model of a four-stroke spark-ignition engine has been developed for application to dynamic engine control. The model responds to throttle, air/fuel, EGR, spark advance, and load torque inputs to provide manifold pressure, net torque, and engine speed outputs. The dynamic aspects of the model are due to time delays and integration. Nonlinear relationships are incorporated to predict engine performance over a broad operating range. Features of the model include division of the fuel flow into a fast and slow path to produce hesitation, and perturbation of the fuel flow to simulate maldistribution.