The Development Of Electronic Controlling System For Gasoline/CNG Bi-Fuel Engine Based On DSPACE

The problem of environmental pollution and energy crisis is becoming more and more serious.As an alternative clean energy,natural gas has been used in all industries widely.The Gasoline /CNG Bi-Fuel Engine has been widely applied in the city taxi and bus system because of its good economy and emission performance and low cost.The difficulties and key points of the development of the Bi-Fuel engine is the electronic control unit of gas system.Using traditional manual code to develop electronic control unit will not only take a long cycle and high cost,but also be complicated to modify the test in later part.Computer-aided design is gradually replacing it as the first choice of developing modern control system.In this paper,the RTI module in the dSPACE system is combined with MATLAB/Simulink to establish the rapid control prototype of the Gasoline /CNG dual fuel engine gas system.Two kinds of automatic switching modes are developed to meet the switching requirements of the engine under different operating conditions.An open loop control module is designed to ensure the dynamic response of the engine.In addition,the correction of the acceleration and deceleration,the temperature correction and the pressure correction are developed to improve the effect of the open-loop control.Based on the oxygen sensor signal of the original vehicle,the closed-loop control module of air fuel ratio(PID)is developed to realize the accurate control of the air-fuel ratio and to improve the emission performance of the engine.Based on the closed-loop control,develop self-learning function module,which can compensate the offset of the jet MAP caused by the aging and wear.Combined with the oxygen simulation module,it can be used to calibrate the jet MAP,which greatly reduces the time required for the calibration of jet MAP.