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The automotive manufacturers today have to put more products faster to the market using shorter vehicle development time and also face significant challenges in vehicle design optimisation due to trade-offs mainly caused by increased focus on fuel economy and CO2 reduction. The market expectation on vehicle acoustics refinement is also increasing and plays a significant role in terms of product perception. With extensive introduction of enablers for improved fuel economy, like automated combustion engine stop/start system as well as down speeding/sizing and more aggressive shift maps for automatic transmissions, additional requirements and development tasks are needed for the noise and vibration (N&V) integration of a driveline. The scope of this paper describes the application of transfer path analysis techniques for low frequency driveline excitation at different low engine speed driving conditions focusing on engine start-up/shut-down events.

The competition in the automotive market enforces shorter vehicle development time in order to get products faster to the market. In addition the customer expectation on interior noise, vibration and harshness (NVH) refinement is increasing and has an important impact of the perception of the product. The focus on fuel economy and CO2 reduction leads also to significant challenges in the vehicle development, which may result in trade-offs for NVH performance. Today's direct injection turbo charged diesel and gasoline engines exhibit both high low-end torque, which gives the customer a pleasant drive quality and improved fuel economy. However, the NVH integration challenges become significant due to mainly structure borne noise transfer through both the driveline itself and the powertrain mounting systems. In addition, the impulsive noise due to the combustion process itself in especially diesel engines needs to be refined.