A Performance Improvement in Idle-Speed Control System with Feedforward Compensation for the Alternator Load Current

It is well-known that decreasing idle speeds is one of the ways to reduce fuel consumption. On the other hand, it is also well-known that even slight fluctuations of the idle speed cause unpleasant vibrations of the vehicle when this speed is set at low values. Therefore, it is important to create idle-speed control (ISC) systems that undergo less idle-speed fluctuations with respect to various load disturbances, in order to reduce fuel consumption without giving rise to unpleasant vibrations.

The first topic of this paper is a linearized model which derives a new feedforward compensation method for reducing idle-speed fluctuations caused by load distrubances for specific electric loads. The second concerns the control results of our ISC system using this feedforward compensation. The final topic is a discussion of the validity of the parameter values used in the feedforward compensation.