Adaptive Control Spark Timing For Gasoline Engine To Reduce Pollutant Emission During Cold Start

With a rapid increase of the global automobile ownership, the exhaust gas ofautomobile has brought more and more pressure to environment. Gasoline engine asmost of the car power output device, the amount of pollutant emission during cold starttakes about 60%-80% of the whole processes, therefore, reduce the pollutant emissionof cold start process became the key of reduce vehicle emission. At present, thedomestic and foreign scholars have a lot of researches on cold start process. It’s verypractical significance that based on adaptive spark timing control to reduce pollutantemission during cold start on this background.A thermodynamic model of exhaust pipe during the cold start process is built inthis paper. Based on the classic formula of mass burning rate in combustion model, getthe mass burning rate of different spark advance angle and different crank angle. Basedon mass burning rate with the low heating value of gasoline to calculate, get heat fluxof combustible mixture. Based on theoretical knowledge of engineeringthermodynamics, a heat flux model of spark advance angle with heat flux in three-waycatalyst entrance is built. This model is the thermodynamic model of exhaust pipeduring the cold start process. The model is built and simulated in Matlab/Simulink, getdifferent curve of the heat flux in three-way catalyst entrance with different sparkadvance angle.A system of adaptive spark timing control for gasoline engine is built in thispaper. In order to reduce the pollutant emission during cold start process, the systemshould retard spark advance angle appropriately with the speed of the gasoline engineand three-way catalyst temperature as feedback signals. The temperature of exhaustgas increased and‘light-off’time of three-way catalyst be shorted by retard sparkadvance angle appropriately. The method for diagnose misfire in gasoline engine byspeed fluctuation signals, and to determine the angle of retard spark advance. The timeof close the control system depends on the signal of three-way catalyst temperature.