Gasoline engine idle speed control system development based on PID algorithm

One of the often-running modes for a gasoline engine is idling, and idle speed stability is one of the key aspects to evaluate a vehicle's performance when it is equipped with a gasoline engine. Therefore, it is very important to control the idle speed stability and to keep the idle speed constant in spite of the various engine load disturbances. In order to reach this goal, usually the closed loop control is applied. Among various control algorithms, traditional PID algorithm has been used successfully for many applications. The key advantages of PID control are its simplicity and practicality. Its control parameters can be tuned on line; the flexibility of its software development makes it easier to get a better control result. In this paper, based on PID control algorithm, an idle speed control system for 462Q electronic controlled gasoline engine is developed. The hardware design of this system, the design of the digital PID controller, the selection of the sample interval and the method for tuning the control parameters are introduced in detail.