Simulation Of Ignition Timing And Maneuver Of Fault Model Effect On Gasoline Engine

Because of energy crisis and stricter exhaust emission law in recent years in China, energy saving and environmental protection become two focuses for the development of automobile. Engine management system, which realizes the optimal matching among engine performance ,energy saving and environmental protection through controlling the ignition timing and fuel injecting, becomes the core technology in automobile development. Each academe and automobile manufacturer is dedicated to develop and research it and has made some effective efforts. The focus of the research is how to find the best optimal parameter between ignition and injection to make the engine response more quickly and exactly. An dynamic simulation engine model using computer simulate technology can analyze each single engine design and control parameter one by one and conquer actual measure difficulties .At the meantime, it can achieve the best matching among engine performance , design and control parameter.Because of quick alternation among acceleration , deceleration and the delay of sensors responding, it is impossible to follow up the parameter change of status from sensors signal .To control the engine dynamic course,it is necessary to set up a dynamic model to evaluate the real signal. The engine dynamic model includes throttle model,manifold-intake model, engine torque and engine speed model . The article analyses these model carefully by math method and sets up a dynamic engine model on the basis of these model analysis. According to different status,enginemanagement system must adopt the corresponding control strategy and the article sums up these strategies.To realize these control strategies effectively, the analysis of simulation can be carried out by the dynamic simulation model in order to obtain the best control of the engine.To simulate the corresponding engine performance during different ignition timing, the article draws the ignition timing surface to find out the Maximum Brake Torque timing(MBT). At the meamtime, to obtain the practical torque,the article draws the revised ignition timing graph to revise the theoretical indicated torque and simulate the torque output of engine when the spark_advance angle is 5,10 and MBT.When sensors failed,the engine management system adopt the maneuver of fault model effect, which affords a substitution signal, to decrease the negative influence on engine performance and emission through fuel trimming . It is necessary to set up lookup table and control logic on fault model. The article draws a response surface among engine manifold_ intake air pressure(MAP), engine speed and throttle position(TP) and establishes the control logic aimed at the fault of engine speed sensors,throttle position sensors , manifold_ intake air pressure sensors andO2sensors.Then, the article simulates the engine performance when TP and MAP failed.Furthermore,the article designs the basic circuit, of which ATMEL89C4051 is the core CPU ,to control igniting and injecting signal.