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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.

A structural analysis for the connecting rod was performed in consideration of bearing crush, oil clearance and initial deformation of the big end bore caused by tightening force of the rod bolts. This analysis enabled to calculate not only the bearing pressure distribution but also the three-dimensional stress state with accuracy. A new fatigue criterion for multi-axial out-of-phase stress was proposed by using mean stress tensor and alternating stress tensor of complex number in this study. This criterion was developed to improve the classical multi-axial “yield criteria”. This criterion is simple, comprehensive and suitable for the evaluation of three-dimensional FEM results. The connecting rods exhibiting high reliability under severe conditions were investigated through the stress analysis and the new evaluation criterion.