Experimental Acoustic Analysis of the Intake and Exhaust System to Predict Insertion Loss and Engine Performance

The pulsations in the intake and exhaust systems affect both the intake and exhaust noises and the engine torque. The pulsations are mainly dominated by the standing waves, which are expressed by the acoustic characteristics. From this point of view, authors have developed an experimental method to analyze the standing wave and the acoustic transfer matrix, which is characterized as the four-pole parameters of the air column in an intake and exhaust system.

In this paper, the intake and exhaust noises are predicted with the insertion loss based on the experiment. By using this method, first the experimental transfer matrix of each sub-system is obtained, then that of a whole system is superimposed from a combination of sub-systems. A proper combination of experimental transfer matrices and calculation ones enables to simulate the insertion loss with accuracy and efficiency. The engine torque is predicted by referring the standing waves which indicate the in-phase and 180 ° out-of-phase modes related to the pulsation types.