Multi-objective optimization simulation to improve combustion noise and fuel consumption simultaneously was previously reported. The report showed that the simulation demonstrated the effectiveness of the optimization of combustion noise and fuel consumption but prediction accuracy of the exhaust emission was insufficient. In addition, precise reproduction of the optimal cylinder pressure waveform which can be obtained from the simulation remained an issue. This report discusses an improvement of the prediction accuracy of the exhaust emissions by employing the detailed combustion model and shows the result of the verification experiment with the direct acting piezo injector.