<div class="section abstract"><div class="htmlview paragraph">Along with the increasing importance of battery electric vehicles for the
automotive industry, new challenges have emerged in the development process of
the acoustic behavior of the electric powertrain. One concern arises from the
high-frequency whining noise, either caused by the electric field of the motor
or by the gearbox. Noise is transmitted via two different paths, the
structure-borne path and the airborne path. The focus here is on the latter one,
which describes the radiated sound from the surface of the motor housing and the
transmission through the car body to the driver’s ear.</div><div class="htmlview paragraph">One possibility for reducing the effect of this acoustic radiation is the
application of passive acoustic noise control treatments. This is typically done
either by attaching secondary treatments on the vehicle-body side or by
encapsulating the motor directly. Depending on the applied material concept, the
motor-mounted encapsulation approach isolates the motor and/or adds absorption
to the engine bay.</div><div class="htmlview paragraph">To implement a process for the prediction of the acoustic isolation effect of
encapsulation in the early design stage, an investigation has been undertaken
where different material concepts are applied to a generic motor housing (GMH).
The isolation performance of these encapsulation concepts is evaluated by
exciting the housing with an electrodynamic shaker and measuring the radiated
sound power. First, the investigation is performed experimentally; afterward,
corresponding simulations are validated by test results. Various conclusions can
be drawn from this study for certain aspects of the process and the simulation
model.</div></div>
