MMLV: NVH Sound Package Development and Full Vehicle Testing (2015-01-1615)

The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-1 vehicle design, comprised of commercially available materials and production processes, achieved a 364 kg (23.5%) full vehicle mass reduction, enabling the application of a 1-liter 3-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper includes details associated with the noise, vibration and harshness (NVH) sound package design and testing.Lightweight design actions on radiating panels enclosing the vehicle cabin typically cause vehicle interior acoustic degradation due to the reduction of panel surface mass. To reduce this deficiency, an MMLV vehicle sound package development was conducted to improve NVH performance of MMLV with ultra-light weight sound package technologies. The project goal was to improve acoustical performance of MMLV by 2 dB without increasing the total sound package weight of “Vehicle A” which is the baseline vehicle for MMLV.This paper presents the lightweight sound package development process for MMLV as well as the full vehicle NVH test results in the high frequency range of 200-10000 Hz. Floor damping treatment strategy and body NVH test results in the low frequency range are also discussed.Full vehicle SEA (Statistical Energy Analysis) simulations are used to evaluate and guide the design and development of MMLV sound package. The final MMLV vehicle sound package design improves the vehicle's engine noise reduction (ENR) by 3.3 dB and improves the front tire patch noise reduction (TPNR) by 1.2 dB without increasing the baseline sound package weight.