The heat release rate patterns of fuel combustion determines the changing of pressure and temperature of gases within cylinder, and furthermore made an important effect of the fuel economy, power - output, noise level and exhaust emission. In this paper, the authors discuss the fuel economy, power - output and combustion noise of R4102Q D.I. diesel engine.In optimum simulation concerning fuel economy and power-output, the indicative heat efficiency and mean indicative pressure were almost always taken as objective function. In consideration of the effect of gas pressure upon the friction losses of diesel engine, the effetive heat efficiency and mean effective pressure were taken as objective function in this paper. By comparison with testing data, when the instantaneous friction was taken into consideration, the prediction accuracy of simulations was improved.The gas pressure vibration causes by compression and combustion transferred through structure parts and radiated from engine surface. When the transfer coefficient unchanged, by reducing the cylinder pressure level, the combustion noise level will be decreased. In this paper, the authors analyse the effect of heat release rate patterns upon the max combustion pressure, max pressure rising rate, cylinder pressure level and combustion noise level.