Excitation mechanism for engine vibration of half-order components

Abstract

Abstract The excitation mechanism of low-frequency half-order multiple engine vibrations was investigated on the basis of the engine excitation forces. The result can be summarized that, since half-order multiple components of the engine excitation torque have a different working point and a different phase angle in each cylinder, the combined torsional moment acts on the cylinder block around the crankshaft axis as an internal force, and hence the torsional vibration shape is excited as a half-order multiple. This theory was demonstrated by the experimental operating deflection shape analysis and the finite-element forced response calculation.