Earticle

With the increasing number of vehicles, society and environmental problems become much more seriously. Aiming at the serious problems, CNG engine, which has better emission performance, has been paid much more attention. However, the CNG engine also has its own disadvantages, such as engine power deterioration, great influence of different mixture ratios of the gas and air on the optimum ignition time of the engine, and so on. Therefore, adaptive control for the air-fuel ratio and ignition timing should be properly adjusted with the consideration of the engine power, economy and emissions. There are two methods of controlling the ignition timing: mechanical and electronic control. In this paper, we develop an adoptive control method based on electronic control. According to the verification, the method can improve the efficiency of the CNG engine. It can be shown the validity of the adoptive method.