A thermodynamics model for the compression and expansion process during the engine’s motoring and a new method for the determination of TDC with simulation technique

In this paper, a thermodynamics model describes the pressure change during the motoring process of the internal combustion engine was given based on the mass conservation, energy conservation law and the state equation of perfect gas. The factors that affect the maximal pressure point position relative to the minimal volume point (top dead center) were analysed with the thermodynamics model. The one to one correspondence between the geometrical characteristics of the pressure diagram and the maximum pressure point position relative to the top dead center (TDC) was proven. Based on the model described, a new method for the determination of the TDC of the internal combustion engine was given. The simulation and experimental results indicate that the new method could determine the top dead center with an error smaller than 0.05 crank angle.