Study On The General Relationships Of Heat-work Conversion Process In Cylinder And Power Performance For Gasoline Engines

Under the pressure of increasingly stringent fuel economy regulations and all kinds of other competitive new energy powers, gasoline engine, as the main form of vehicle power has to be created with energy conservation and emission reduction. At present, in consideration of the situation that mo st of the gasoline engines have a relatively low thermal efficiency and indicated performance, therefore, to improve the efficiency of heat-work conversion in cylinders and the abilities to work in cycles would be the most powerful way for gasoline engines to achieve a better power performance and improve its fuel consumption economy as well. Based on the data of actual measurement for three gasoline engine’s bench test, analyzed the influence rule of the operational parameters and the state parameters to e ngine performance, deeply summarized and optimized the general relationship of influence factor during the heat-work conversion process. And further modified the theory of traditional internal combustion engine, which provide more reliable protection with better accurate to establish a simulation mode for the performance development of gasoline engine.At first,this paper, on the strength of thermodynamic balanced equations and state equations, studied the working medium during the gasoline engine heat-work conversion process,and summarized some relative elementary knowledge of combustion heat release rule that the most direct factor that influence the conversion process. This paper disintegrated the cyclic process, transferred the research emphasis into high pressure and power cycle which has a more distinguish influence to heat-work conversion.Meanwhile,the paper named some key influencing parameters, which are the theory foundation of studying common rules. The dimensionality and breadth of the influence factors for modern engine has been greatly beyond the traditional theoretical description of the internal combustion engine, therefore, it is necessary to further improve the governing equation of gasoline engine, compared with the measured data, and then the accurate of the control equation could be proved in a good way.After further optimized the dimensions of the governing equation, based on the elementary knowledge of thermodynamics and numerical calculation, the simulation mathematical model could be developed from the EXCEL VB platform. Calibrate that simulation mathematical model,and, the structure parameters of air cylinder and the operational parameters of gasoline engines would be the only thing needed to simulate the conversion of heat into power in a precisely way, which also could calculate the influence of those parameters to the conversion accurately.This simulation mathematical model is similar as a virtual engine whose control variable includes the inlet parameters, the excess air coefficient, the combustion efficiency, ignition timing, the phase angle of inlet and exhaust value, the combustion duration,etc.The simulation mathematical model was applied to a gasoline engine; the results show that this model reflects the rule of the thermal power conversion process more accurately and could be used to study the sensibility of thermal power conversion process. The concept of optimal parameter combination based on the identical knock ing tendency has been brought up that the optimal combination means using geometry compression ratio, accelerating the combustion, putting off the intake valve closure timing and the advance angle of ignition to get a high efficiency of conversion and avoid knocking at the same time.