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Powertrain and driveline systems interaction in rear wheel drive vehicle development has recently gained attention for the improvement of interior noise and vibration in emerging markets. The driveline is a significant path for engine-generated noise and vibration to reach the interior occupant interfaces, where it affects refinement perception. The interaction of powertrain excitation orders and driveline resonant responders covers a wide range of frequency and vehicle operating conditions. This interaction poses significant challenges during vehicle development. With recent increased demand for higher specific power from diesel engines, driveline refinement has become even more challenging, especially for rear wheel drive vehicles. Two driveline related refinement issues were observed during evaluation of a RWD vehicle. Root cause analysis determined that the first issue (lower rpm boom noise and vibration) was due to engine torsional excitation of the driveline.

Automotive manufacturers are facing unprecedented cost challenges across globe. Market requirement has become very competitive with increased demand for higher performance and value engineering. This is encouraging automotive manufacturers to develop dampers with local suppliers, as there is a huge component cost advantage and also logistic cost savings. However, in emerging markets, supplier capability to develop the component for solving particular NVH problem of OEM is not matured as compared to developed market suppliers. The challenge for auto makers is to develop suppliers who can provide proper performance and durability, while at the same time providing lower cost components. This paper gives an overview of the challenges in the development process to develop a competitive torsional vibration damper for rear wheel drive vehicle to reduce boom noise and vibration.

A turbocharger unit mainly consists of a centrifugal compressor and a turbine coupled together by a solid shaft. This is employed to boost the charge air pressure of the engine. Turbocharging in modern diesel and gasoline engines have become a common and essential operation to result higher power outputs, lower emissions, improved efficiency and refinements from a similar capacity of naturally aspirated engines. The automotive turbocharger system is a source of synchronous and asynchronous noises that should be eliminated or reduced for passenger comfort. Subjectively, a high whistle noise was audible in the passenger cabin during in a mid-rpm range drive in all gears in a 4 cylinder diesel vehicle. Objective noise and vibration data confirm the issue as unbalance whistle. A detailed study has been carried out to identify the source and radiating part of the unbalance whistle noise generated in a 4 cylinder diesel engine running a passenger car.