An Automotive Supercharger Noise Test Rig Incorporating Torsional Excitation

Superchargers driven by a front end accessory drive belt are subjected to torsional excitation induced by engine speed fluctuations caused by cylinder-firing impulses transmitted to the engine crank pulley. These impulses are transmitted readily through the belt system to all the accessories as a time-varying angular displacement. A test rig incorporating torsional excitation has been built for the investigation of torsionally-induced rattle noise in automotive superchargers. With the engine itself and associated background noise eliminated, the rattle noise induced by torsional vibration can be directly investigated. An example is given showing the high correlation between vehicle and test rig measurements.