Development Strategies for Creating Quiet Vehicles: Insights from a 35 -Year Veteran

From the early 1980’s through 2015, the engineering community has witnessed dramatic changes in the technology for mitigating sound in vehicles. Throughout these years, vehicle noise, vibration, and harshness (NVH) engineers were skilled and talented in testing vehicles, and at conducting laboratory studies of materials and trim-insulator components. This paper surveys a wide variety of processes that NVH automotive engineers use to develop trim-insulator packages which are effective in reducing cab-interior noise while being esthetically appealing. Analytical models are used to cascade overall cab-interior sound pressure level (SPL) targets to trim-insulator performance targets. This paper also reviews how sound absorption is employed to reduce cab-interior SPL. Acoustical material laboratory tests are briefly described along with the role they play in selecting trim-insulator products for vehicles. And finally, body shell acoustical isolation is examined, and a mathematical relationship is derived between cab air-leakage and acoustical degradation.