Transient effects and torque control of engines with variable cam timing

A dual-equal variable cam timing (VCT) system implemented in an SI automotive engine improves performance in terms of emissions, fuel economy, peak torque, and peak power. A drawback of the technology is a deterioration in transient response of the engine that may affect vehicle drivability. Several methods to improve transient performance of a VCT engine have been proposed in the literature. The purpose of this paper is to report experimental testing results for a feedforward VCT controller proposed by Jankovic et. al. (1998). The paper also describes the hardware setup and addresses several issues relevant to controller implementation.