For predicting the performances of the four stroke cycle spark ignition engines. the gas behavior in the engine system has been analyzed. The calculations consist of two parts. the calculation of the gas behavior in the intake and exhaust systems which was described in the first paper, and the calculation of the variations of gas properties inside the engine cylinders. In this Paper the simulations for the in-cylinder processes were described for the MPI engine, naturally aspirated and turbocharged engines with a carburettor. With the combination of the calculations of the intake and exhaust systems and the calculation of the in-cylinder processes. the predictions of the engine Performances and the exhaust emission characteristics were carried out. And the result showed good agrements with the experimental results under wide range of operating conditions.