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Adaptive control techniques have been applied to the problem of diesel engine torque control. Adaptive control has the potential of greater versatility than classical control techniques. Three adaptive control strategies are tested and compared to each other: self-tuning control with one-shot parameter identification and controller design, self-tuning gain-scheduling control, and self-tuning control with continuous adaptation of system and controller parameters. A continuous-time parameter identification approach, namely the Poisson moment functional (PMF) method, is employed because of its superior noise rejection capability. In order to ensure the applicability of time delay systems, a Smith predictor is employed. The controller design is implemented by using a new pole-zero placement algorithm to ensure closed-loop stability. Comparisons with constant parameter controllers reveal that adaptive control provides equal or better torque control than a constant parameter controller.

A digital torque controller capable of following the EPA transient test cycle was developed for both a turbocharged diesel engine and a direct current dynamometer. A simplified mathematical model for the throttle-torque system was developed. Off-line parameter identification algorithms were used to find the model parameters. The controller design was carried out using a closed-loop pole assignment technique. Since the model included time delay, a Smith predictor control scheme was used. Feedforward control was added to the Smith predictor for load disturbances caused by speed variations of the engine. Transient engine tests showed that the Smith predictor with feedforward disturbance rejection gave transient cycle performance well within the specifications of the EPA.