Contributions on modeling the intake and compression processes of the spark ignition engine

Because of the the complexity of the phenomena and different operating modes of the spark ignition engine, used in vehicle propulsion, it was prepared a simulation, in order to optimise its co-operation with the vehicle, using a theoretical model, developed by the authors. The proposed model addresses to the intake and compression processes, considered to have a major importance, influencing the evolution of the engine operating cycle and implicitly, the overall performance. This paper, through the developed model, leads to the achievement of functions that emphasise the variation of the pressure and temperature of the fresh load at the end of the intake process, together with the engine load modification, at different engine speed values in the operating range. The calculation expressions of the pressure and temperature at the end of the intake process are also developed, depending on the engine load. The main results obtained derive from the performed simulation on the modification of the parameters that characterize the intake and compression processes for the spark ignition engine.