Modeling, Identification, and Torque Control of a Diesel Engine for Transient Test Cycles

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.