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This paper describes a diesel vehicle NVH development process which has been applied to achieve a number of best in class products in the European diesel marketplace. It focuses upon: Key diesel vehicle NVH issues Critical success factors in the NVH development process NVH methodologies, tools and techniques which support this process Case studies using results taken largely from a luxury sedan vehicle development program are used to highlight the issues and to demonstrate the success of this process in achieving a vehicle with high diesel appeal. The paper concludes with an insight of how this process is being adapted and refocused to reflect the anticipated requirements of the potential US diesel vehicle marketplace.

Today vehicle owners perceive squeaks and itches inside a vehicle cabin as a major negative indicator of vehicle build quality and durability. Manufacturers struggle to bear the high costs of squeak and rattle (S&R) related warranty. Although the benefits of structural integrity and tight manufacturing tolerances with respect to the prevention of S&R are known, today's cost, weight, crash requirements, aesthetic demands and environmental/fire hazard rules quite often dictate the design of S&R prone sub-systems. Even sub-systems with the best possible structural design and manufacturing tolerances are not immune to extreme environmental conditions, and mating materials can initiate contact leading to S&R. One method of minimizing the possibility of squeaks is by the judicious selection of mating material pairs. This paper describes a test process aimed at the quantification of material pair compatibility.

The more noise and vibration improvements are incorporated into our vehicles, the more customers notice squeaks and rattles (S&R). Customers increasingly perceive S&R as a direct indicator of vehicle build quality and durability. The high profile nature of S&R has the automotive industry striving to develop the understanding and technology of how to improve the S&R performance in the vehicle. Squeaks and itches make up a significant amount of Squeak and Rattle complaints found in today's vehicles. Squeaks and itches are the result of stick slip behavior between two interacting surfaces. Squeak itch behavior is dependent upon a large number of parameters including but not limited to: the material itself, temperature, humidity, normal load, system compliance, part geometry, velocity, surface roughness, wear, contaminants, etc. This paper will describe the analysis of sound data and friction data and the relationship between them.

Advancements in the area of noise and vibration control have succeeded in quieting the vehicle to the point that previously obscure squeak and rattles must now be addressed. One possible way to decrease the squeak levels is by judicious selection of the material friction pairs. The squeak levels produced by a given material friction pair are a function of a number of test conditions like interference, temperature, humidity and excitation frequency. This paper experimentally studies the dependence of squeak levels on these factors. Understanding the relationship between squeak and test conditions will guide the selection of materials and help us to carefully select the test conditions for squeak evaluations. It will also result in cost reductions to otherwise numerous and expensive squeak parameter testing.

Modern trends in noise control engineering have subjected the automobile to the “drained swamp” syndrome. Squeaks and rattles (S&R) have surfaced as major concerns. Customers increasingly perceive S&R as direct indicators of vehicle build quality and durability. The high profile nature of S&R has led manufacturers to formulate numerous specifications for assemblies and components. Even so, a large majority of buzz, squeak and rattle (BSR) issues are identified very late in the production cycle, some often after the vehicle is launched. Traditionally, the “find-and-fix” approach is widely adopted, leading to extensive BSR warranty bills. The “design-right-the-first-time” approach must replace the “find-and-fix” approach. Due to the vast breadth and depth of S&R issues, a comprehensive summary of the present state of the art is essential. This paper includes a literature survey of the current state of the art of S&R, and discusses the methods available to further advance it.