MODELING OF VIBRATION TRANSMISSION IN ENGINES TO ACHIEVE NOISE REDUCTION

The vibration transmission in engine structures has been studied to develop analytical models which predict changes in the noise related vibration of the engine as a function of design changes in the engine components. The models are based on vibration measurements made on non-running engines. This paper outlines the basic procedures for the necessary vibration measurements and for the development of the models. Two examples are given of models developed for different vibration transmission paths in different engines. The vibration transmission from the cylinder pressure to the engine block is modeled for a 4 cylinder DI diesel engine and compared with a simulated vibration transmission measurement with the engine not running. The vibration transmission from the engine block to covers and shields is modeled for a 6 cylinder in-line diesel and compared with the measured vibration transmission with the engine running.