Research And Development On Knock Control System Of Coal Bed Methane Engine

In recent years,as energy and environment problems are more and more severe,the application of gas engine is increased.Backfire and blasting frequently arise due to instable gas parameters such as composition,pressure and so on.Turbocharged coal bed methane engine often has serious knock.So ignition system of traditional gas engine could not meet the ignition demand of coal bed methane engine.In order to solve this problem,a gas engine knock control system is designed in this paper.In this paper,a kind of knock control project for coal bed methane engine is proposed, which implements knock control with knock signal as feedback signal and using advanced angle of ignition as adjusting object.The key for knock control is extraction of knock signal eigenvalve.So wavelet transform in combination with FFT approach is proposed to extract knock feature,which is proved to be effective and feasible through signal processing.The design of hardware and software are illuminated in detail.Hardware design inludes: controller and sensors,input signal circuit,ignition circuit and power supply circuit,etc. Software design includes:main program,initializing subroutine,data processing module, knock control module,ignition control module,etc.In addition,effective anti-interference measures are adopted in design of hardwares and softwares.Finally,the hardwares and softwares of knock control system are debugged on test-bed. Experiment results indicates that the R&D target of knock control system has been achieved, foundations are established for future optimization of knock control system of coal bed methane engine.