Abstract
The increased importance of the vibrational and acoustic comfort of passenger cars, one aspect which emerges from surveys of customer expectations and complaints is the requirement for a new, improved approach for addressing vehicle NVH performance. Specific, precise targets, based on a clear product characteristic definition and on systematic benchmarking activities, must be defined to represent vehicle performance reliably; furthermore, vehicle targets have to be cascaded down to the subsystem level in order to monitor and verify their 'achievement' during the product development process, the aim being to reduce dramatically the number of the problems to be solved through testing on prototype vehicles.
As a direct consequence, the role of testing in the vehicle development process is evolving: the reduced emphasis on prototype testing is being balanced by an increased need for benchmarking and detailed experimental characterisation required for the definition of vehicle NVH targets. Specific testing techniques have been developed for assessing vehicle NVH performance and for the deployment of targets at the subsystem and component level.
This new approach, which requires systematic application to be effective, has been implemented in Fiat during recent years for the NVH development of the latest generation of passenger cars and could in future be extended to other vehicle performances and to other types of vehicles (trucks, agricultural and construction equipments, etc.).