Study On Combustion Characteristics Of Gasoline Engine Under Accelerated Transient Operating Conditions

Automobile is often in accelerating transient conditions during driving, but the fuel consumption and harmful exhaust emissions will increase under this condition, which limits automobile dynamical and fuel economic characteristic on a certain degree. The author took experiment of the two typical conditions which involved in free and taking along the speed characteristic curve acceleration, and established the transient two-zone combustion model according to the characteristics of gasoline engine transient combustion process. Simulation analysis was carried out on the gasoline engine combustion process so as to seek the combustion regulations and optimize the work process of gasoline engine under transient operating conditions.In this paper, on the basis of synthesizing the research on the characteristics of gasoline engine transient combustion process at home and abroad and the Projects(51176014)supported by the National Natural Science Foundation of China and The Project(20104316110002) of Special Scientific Research Fund for Doctoral Program of University. Transient combustion characteristics of gasoline engine were studied combined experiment with model. The main innovation points and the research work of the paper are as follows:(1) In this paper, a pressure signal filtering method was proposed based on the analysis of the spectrum of the dynamometer and theory of digital filter, and adopting the method to smoothing transient indicator diagram was proposed. The results show that the effect is obvious.(2) Transient two-zone combustion model based on the quasi- dimensional combustion model is established, and compared the calculated values with measured values to verify the model. The results show that the effect is obvious.(3) Experimental data is managed and combustion characteristics of gasoline engine is respectively analyzed in accelerated transient conditions for the two typical conditions from the maximum combustion pressure, the indicated mean effective pressure and indicator diagram. The transient combustion process is stimulated and analyzed through adjusting themodel parameters and some rules which is effected by changing of main characteristic parameters of the gasoline engine is revealed.