Achieving Diesel Vehicle Appeal Part 2: Powertrain NVH Perspective

Diesel vehicle sales in the European passenger car market are rapidly approaching 50% market share. This rise in penetration has been achieved because buyers are attracted by the fuel consumption benefits of diesel powertrains and are now able to select from a wide range of desirable products with excellent performance and levels of refinement competitive with gasoline powered products. In a highly competitive marketplace there is increasing emphasis on the development of appealing diesel products, with the dominant factor being powertrain NVH performance.

This paper compliments an earlier paper [1] on the vehicle NVH process required to achieve high ‘diesel appeal’ by providing a more detailed powertrain NVH perspective. It focuses upon:

• Key powertrain NVH issues
• NVH target setting at a powertrain level
• Combustion system design & calibration optimization
• Powertrain structural optimization

Case studies are drawn from a range of relevant powertrain NVH projects to illustrate the application of key supporting tools and technologies:

• Combustion noise analysis including noise source identification, characterization and monitoring using a novel analyzer system
• Combustion noise optimization using a design of experiment approach
• Optimization using structural attenuation prediction

The paper concludes with an insight into the future challenges in diesel powertrain NVH development that will be generated by increasingly stringent emissions requirements and a marketplace which will demand continuously improving levels of ‘diesel appeal’.