Toyota's New Type of Crankshaft Pulley to improve the Compartment Tone Quality

An investigation was made into the intermittent rumble audible in the passenger compartment during acceleration. Results revealed that the noise is caused by a resonant bending vibration of the crankshaft with cyclic fluctuations occurring when the no.1 cylinder fires.

A description is given of a new type of crankshaft pulley with a bending damper developed to minimize this vibration, and its effectiveness and reliability are discussed.