Identification of the Relation Between Crank Shaft Bending and Interior Noise of A/T Vehicle in Idle State

This paper shows the cause and the solution to the uncommon noise which happens ½ order component of engine rpm when a vehicle with automatic transmission has an air conditioning load and “drive” range load on the engine.

By measuring cylinder pressure, main bearing cap vibration, engine mount vibration, and interior noise simultaneously, the cause of the noise can be proved by analyzing and comparing the data. The cause of the uncommon noise is bending vibration of the crank shaft. To solve the problem, one can change the crank shaft dynamics by reducing the mass of the damper pulley.