The A/F Ratio Closed-loop Control Of Electronically Controlled Carburetor System Based On MAP

At the present time,China is already the biggest market of motorcycle and the biggest motorcycle maker around the world. In order to tackle the environmental problem caused by emissions form the exhaust gases of motorcycles, the National Stage-ⅢEmission Standard is about to be put in force in order to stimulate motorcycle makers to renovate old technology to meet the rigorous regulation. Though the electronic fuel injection (EFI) technology can make it, the core technology is in the control of foreign firms, and it is too expensive for Chinese motorcycle consumers right now. Therefore, we must develop a cheap method to meet the newly launched standard.The model of electronically controlled carburetor in this thesis is an open loop control model based on MAP, with feedback control based on signals from exhaust gas oxygen sensor. In order to compensate the excursion of the switch type exhaust gas oxygen sensor, a sensor reference voltage control technique is introduced. The effect of the reference voltage on A/F ratio has been proven. Electronically controlled carburetor technology is one of the three technology routes recommended to meet the National Stage-ⅢEmission Standard, involving a three-way catalyst. With minimized refit, it is absolutely the best method to deal with the challenge. The hardware and software were designed, refined over and over again based on a mass of experimental data, this system can keep the excess air coefficient fluctuating around 1, exactly where the catalyst works with the highest efficiency, reducing air pollution emission sharply, especially the NOX.