Analysis of Impulsive Powertrain Noise

Refining vehicle NVH is a key aspect of the powertrain development process. Powertrain NVH refinement is impacted not only by overall sound levels, but also sound quality. Powertrain sound quality and therefore the level of NVH refinement can be adversely impacted by excessive impulsive noise. A process is outlined in this study to comprehend the occurrence of impulsive powertrain noise. Additionally, a process has been developed that identifies the source of the impulsive powertrain noise and is illustrated in this study through examples from case studies. Special emphasis has been placed on primary sources of impulsive powertrain noise such as diesel knocking noise, injector ticking, impulsive cranktrain noise, and gear rattle. A portion of the analysis involved the development of key objective metrics, optimization measures, and the examination of the potential for improvement. The metric development process, where possible, considers the correlation with subjective studies. The optimization process that was created highlights the various engineering alternatives that have been developed to control the specific impulsive powertrain noise issues.