Development of Vehicle Dash and Floor Subsystem Sound Packages for Lightweight Vehicle

The Multi Material Lightweight Vehicle (MMLV)1 has been developed with a collaborative effort between Ford Motor Company, Magna International and US Department of Energy and achieved 23% weight saving using lightweight materials and manufacturing technologies. Lightweighting in vehicle design is prone to generate higher vehicle interior noise levels due to road, wind, and powertrain noise. In order to meet interior noise level targets in lightweight vehicle design, there is a need to develop new vehicle sound package materials and designs. This paper discusses the sound package design and development for MMLV to improve engine noise reduction and tire noise reduction performance. MMLV dash and floor subsystem Statistical Energy Analysis (SEA) models were developed to guide the design of dash and floor acoustic sound package. Dash and floor lightweight subsystem bucks were built and tested in a sound transmission loss (STL) test suite. Tests were conducted with a number of sound package iterations to validate SEA models. Subsystem CAE-Test correlation results are presented. This paper demonstrated that the absorption strategy is an effective approach for lightweight vehicle design to recover NVH degradation. Implementation of new light sound package design significantly improved acoustical performance of MMLV vehicle design without adding weight.