Current and future EV’s contain significant amounts of complex electrical hardware, including rechargeable energy modules, control units, cooling systems and wiring situated inside the cabin usually below the carpet, seats or trunk trim and below the cabin floor. These items, whilst likely to have a direct impact on transmission loss, are increasingly difficult to evaluate via typical methods of computer-based simulation. In particular, the packaging space allocated for control units, which may require an air gap between the body in white and the carpet for aspects of heat stabilization can be difficult to model using the transfer matrix method.
In the case of battery installations their high bulk mass doesn’t necessarily provide significant increases in transmission loss due to adjacent acoustic weaknesses and the inherent sensitivity of the floor system. This paper examines a selection of novel techniques, using sound Phonons, developed to predict both baseline transmission loss and absorption and subsequently acoustic performance optimization. The user-friendly nature of the sound Phonon application enabled “full vehicle” models to be efficiently created for interior and exterior noise prediction. This is particularly useful for EV target compliance evaluation when a platform is undergoing conversion from ICE to EV or assisting a “clean sheet” EV design.