Hardware Development Of An Electronic Control System And Its Experimental Study On A Compressed Natural Gas Engine

Air pollution, global warming and energy shortage are the problems to be solved in the development of automobiles. Natural gas, as an alternative fuel for internal combustion engine, is one effective way to decrease engine emissions, to change energy structure and abate tight energy supply. The development of electronic control technolgy has more and more effect on engine emission reduction, performance enhancement and fuel economy improvement. Therefore, much attention is paid to studying and developing engine electronic technology.Based on a XC164CS singlechip, an electronic control system including programmable peripheral interface circuit, clock circuit, reset circuit and power supply circuit was designed for a multi-point sequential injection natural gas engine. An input circuit of oxygen sensor signal, drive circuit of fuel injection and ignition were also designed. The choice of components, decoupling and filter of printed circuit board wiring and channel separation were considered to improve the reliability and anti-interference capability of the system in the hardware circuit design .Based on the control system, comparative studies were conducted on the variation of air fuel ratio under the conditions of closed loop and open loop air fuel ratio control on a compressed natural gas engine.The study shows that the electronic control system can meet the requirements of natural gas engine tests. Through air fuel ratio closed loop control, the variation of lambda is lower than that at the condition of open loop air fuel ratio control. The electronic control system provides an engine test platform at steady conditions.