Re-equipping Design Of The CNG/gasoline Flexible Fuel Automobile

Along with the fast development of automobile industrial and the continual increase of automobile retain quantity, which bring importance revolution to society, at the same time, also bring a lot of severity problem, such as energy crisis, atmosphere pollution. Seeking automobile substitute clean fuel has become one of the energy conservation and environmental protection efficient paths.As a green fuel, CNG features less expense and rather low exhaust pollution compared to gasoline in the engine fuel application .And our country has large natural gas storage. Thus, applying CNG in automotives could fully utilize the natural gas resource; reduce the exhaust pollution and operating expense of the vehicles.The research of CNG application is just started due to the automotive industry development domestic. Engines specially designed for CNG are rare and the CNG stations are not fully established. So carrying out the application research of CNG based on gasoline engines and developing Flexible fuel engine system for CNG and gasoline has great significance.The massive work are done , The prime task is as follows :Firstly, the differences between CNG and gasoline in the application characteristic and CNG/gasoline dual purpose fuel automobile's merit have been analyzed. And then the system plan based on JETTA ATK engine's Flexible fuel has been Proposed.Through to natural gas motor car engine system's analysis, the dual purpose fuel automobile's overall re-equipping plan .has been proposed based on the fact that Air-fuel ratio and Simulator had been known.Handling logics for sensor signals are developed and related hardware interfaces are designed based on the analysis of important sensors and their signal characteristic; the CNG and gasoline injector characteristic and their demand for driving circuit is introduced. Injector driving circuits are designed, which drive the injectors properly. And the paper introduced the ignition control system and the change-over switch control system with emphasis.This paper regards CNG/gasoline dual fuel engine which works in Electrically controlled multi-spot order injection system, according to the theory that The natural gas octane value is high as well as the flame propagation velocity is slow ,,adopt the method of Increases the ignition angle of advance . the experimented platform has been Built which Examines the plan of Ignition angle of advance in the different situation, contrastive analysis of the Empirical datum, The angle of advance adjustment scheme has been determined which Take the lowest emissions as the goal under Idling regime situation and The angle of advance adjustment scheme has been determined which Take the maximum output torque as the goal under stable state situation. Finally the contrastive analysis of the emissions data explains that When dual purpose fuel engine use natural gas, the influence of ignition advance angle advance is not obvious to CO in exhaust emission as well as the influence of ignition advance angle is obvious to HC,NO_x in exhaust emission, but The ignition angle of advance's appropriate adjustment will reduce HC, the NO_x density greatly.