Increased customer expectation for NVH refinement creates a significant challenge for the integration of Diesel powertrains into passenger vehicles that might have been initially developed for gasoline engine applications. A significant factor in the refinement of Diesel powertrain sound quality is calibration optimization for NVH, which is often constrained by performance, emissions and fuel economy requirements. Vehicle level enablers add cost and weight to the vehicle and are generally bounded by vehicle architecture, particularly when dealing with a carry-over vehicle platform, as is often the case for many vehicle programs. These constraints are compounded by the need to make program critical sound package content decisions well before the availability of prototype vehicles with the right powertrain.
In this paper, a case study on NVH development for integration of a light duty Diesel powertrain is presented. A process, based on a time-domain transfer path methodology was applied to provide focused engineering development of powertrain and vehicle level NVH enablers. Specifically, this paper describes the process of virtually installing a Diesel powertrain into a carryover gasoline vehicle, then later into a prototype development vehicle and target vehicle. Results from the “virtual swaps” were utilized to assess the gaps to NVH targets and to develop a focused plan for development of powertrain and vehicle level NVH enablers.