Engine Noise Reduction Using Self-Tuning Torsional Vibration Damper 2016-01-1063

Up to 30% of engine noise is delivered by front end pulley combined with torsional vibration damper, and technically it is the main contributor to recorded engine noise level. So the novel solutions in terms of improving the design and performance of torsional vibration damper would help to reduce radically this component of engine noise. The results of dynamical study of patented torsional vibration damper combined with pulley are presented. Design and structure of torsional vibration damper is based on author’s US Patent 7,438,165 having the self-tuning control system for all frequencies in running engine in all operational regimes. Mathematical model has been used for the analysis of the emitting noise of engine having proposed torsional vibration damper. Attention is paid to mitigation of the sound power levels contributing by engine subsystem “end of crankshaft - torsional vibration damper - pulley”. Theoretical analysis reveals that the proposed self-tuning torsion damper could nullified the vibration (and, consequently, the noise) consisting of components having up to 9 frequencies. Tests have been conducted in order to get the objective metrics and compare the noise performance of engine completed with new device to data when engine have a conventional torsional vibration damper. The tested engine demonstrated 5.4 dB(A) improvement of overall noise levels due to usage of proposed self-tuning torsional vibration damper.