Optimization of the High Frequency Noise for the Passenger Car Diesel Engine

In accordance with the characteristics of the engine structure and of combustion excitation, diesel engines have distinctive noise characteristics in comparison to gasoline engines. In particular, the combustion excitation of the diesel engine produces significant excitation of high frequency noise. This paper describes the influence of the piston pin clearance, bed-plate design, and transmission bell housing structure, using a variety of experimental methods. Design solutions to improve the high frequency noise of diesel engines are also provided, beginning with identification of the root cause for noise generation, through the design modification of the engine structure, to the control of combustion excitation forces.