Research And Development On Air-Fuel Ratio Control System Of Gas Engine

In this thesis, the developing background, the significance and the research actualities of gas engine and the technology of air-fuel ratio control are introduced firstly. And then, aimed at the existent problems of air-fuel ratio control of gas engine, the main contents of the article are put forward.Researched on the characteristics of 8300-type gas engine and coal bed methane, the general plan of the system based on CMAC and PID parallel control is brought forward, which is proved to be feasible through simulation and analysis.The design project and the principle of the hardwares are illustrated in detail, including the selection of the programmable logical controller, extension modules, the sensors, stepping motor and the driver, and, the design of the collected and processed signals circuit, stepping motor drived circuit, the keyboard circuit, the alarm circuit, display circuit and the power supply circuit, etc. At the same time, design and realization of the softwares are specified, including the main program, the initialized subroutine, the HSC subroutine, the PTO subroutine, the display module, the alarm module, the keyboard operated module and the air-fuel ratio control module, etc. Considering the influence of the outside interferences, effective anti-interference measures are taken to the hardwares and the softwares.In the end, the accomplished control system is debugged including the hardwares debugged, the softwares debugged and online debugged. Autocontrol of air-fuel ratio of gas engine can be realized by the system. Moreover, the operation status of the engine can be real-time monitored, so alarm will be given while the system has faults. The results of debugging show that the expectant target is obtained.