Natural Gas Engine Control System Controller Developed

The gasoline and diesel engine must be changed in order to use the alternative fuel save energy and reduce pollution due to the shortage of the global petroleum resource and the serious air pollution problems. The research of alternative fuel engine tends to be an incrementally important discipline of engine techniques. As an ideal clean alternative fuel for diesel or gasoline, the natural gas has been attended extentively in the world. Thus, CNG engine will have extensive application for its high efficiency and low emission. The study of the techniques of learn burn for CNG engine is an important discipline, the development of the high-powered electronic controlled system has becomed hotspot of CNG engine. The engeering of purging air has been starting, In order to promote the development of the natural gas vehicle techniques in our country, the research on the basal theory and the experiments on the electronic controlled CNG engine should be carried out.The following works has been fulfilled in the dissertation: development of CNG engine is summarized, electronic controlled system of CNG engine is schemed, the 80C196Kc single-chip of Intel corp was adopted as the microprocessor of the ECU to fulfill the task of controlling the Air-Fuel ratio and ignition timing. The hardware and software are included in this system, it has the power source module, the input module, the output module, the microprocessor module and the communication module were designed on hardware;the program of injection and ignition were programmed on software. At last, the result was provided by debugging.The air-fuel ratio has affinity with dynamical, economy, emission performance of engine, so the air-fuel ratio controlled strategy has been studied as important aspect. Several typical controlled stragegy, such as fuzzy controlling, PID controlling,two-dimensions linear insert value etc, have been elaborated and simulated. Moreover, their characters have been analysized from simulated result and the different controlled strategy were adopted for the different working condition.The electronic controlled system of CNG engine achieves the strict control of natural gas quantity and injection time of each cylinder by using the techniques of learn burn and AFRclosed loop control and sequential multiple injection. It meliorates uniformity of fuel mixture in each cylinder and enhances the lean burn limit when CNG engine runs stably. The method of open-loopx grouping ignition is adopted to control ignition advance angle so as to predigest programming. The ignition energy is by developing high energy ignition moduel in this paper. The simulated experiment was done on electronic unit. The result was analysed from HSO injection and ignition pulse width. The AFR was controlled near theory AFR, we found it good from the test result.