Mathematical model of four-stroke combustion engine working process

By defining the fluid's thermodynamic properties, the cycle can be simplified using various assumptions. A lot of models of the combustion engine process were developed that including the thermodynamics, turbulence, and chemical kinetics to predict thermodynamic parameters of the engines. Mathematical model the working process occurring in the cylinder of the four-stroke piston-combustion engine is an object of the paper. The following assumptions consisting in that thermodynamics system is an open thermodynamical system, in accepted model were taken into account. Generalised mathematical model of the working process in the cylinder of the piston-four-stroke combustion engine was worked out. Dependences describing instantaneous volume of the working charge in the cylinder, equation of the balance of the of the working charge quantity in the cylinder and state equation of the working charge in the cylinder were considered at formulating of assumptions. Values of coefficients for each component processes of working cycle with taking into consideration of the dependence concerning the compression process , the combustion process, and expansion process after finishing of the combustion process were an object of worked out mathematical model. For nonstationary processes formulating working cycle of the engine realized during openings of valves (the open system), the quantity and composition of the working charge in the cylinder, its specific heat and temperature are variable. The temperature difference between the working charge and walls temperature of borderering the space of the cylinder was taken into account, too. Generalized mathematical model of the working process in the cylinder of the piston- four-stroke combustion engine applying for the theoretical analysis of the working process in the combustion engine, as well as for working out of experimental results was elaborated.