Sound Radiation Efficiency Research of Engine Parts by the Discrete Calculation Method

In the present paper, the discrete calculation method (DCM) which applies to regular components is presented to some complex components of engine cover parts, and the proposed method is a hybrid method comprising both vibration measurement and calculation of radiation impedance. Since the proposed method does not require the measurement of sound fields, it provides a high precision. By the research of theory and experiment scheme, the usefulness of the DCM as a measurement method for sound radiation is verified by performing measurements of engine oil pan. Then the above achievements were introduced to noise source identification of surface vibration velocity method. From the measurement and analysis of the vibration signal in the rating condition, the sound power level of engine can be drawn. Compared to the noise measurement result, the calculated result was a little higher. We draw from the findings of the present study that the investigation of sound radiation can be used in noise source identification with a high precision.