Engineers crack the whine problem in electric cars through smarter housing design
Researchers have identified how to reduce the high-pitched noise from electric motors by redesigning internal ribs in drive unit housings—a finding that could improve passenger comfort and brand perception as EV adoption accelerates. The work maps specific design changes that lower noise radiation without sacrificing structural strength, giving automakers a practical toolkit for quieter vehicles.
Originaltitel: Rib Design of Electric Drive Unit Housings for Reduced Noise Radiation
Väl utformade ribbor i elmotor-husvagnar kan minska högfrekvent ljudstrålning utan att offra strukturell styrka — ett område där leverantörer och elmotortillverkare kan vinna konkurrensfördelar genom tystare drivenheter. Volvo och Saab har kartlagt hur geometriska egenskaper hos husvagnsribbor påverkar bullret från växel- och motorvinningar, som utgör en kvalitetsindikator trots låga nivåer på grund av deras högfrekventa karaktär. Genom numerisk parameterstudie varierade forskarna ribbdimensioner, tjocklek och krökning för att mäta strålad ljudeffekt och strålningseffektivitet. Resultaten visar att mindre krökning på ribbkanten reducerar ljudstrålning, medan vissa ribbdimensioner kan orsaka omfattande brus genom växelverkan med första böjningsläget. För konstruktörer som arbetar med eldriven fordonsteknik är dessa insikter användbara för att optimera husvattendesign och samtidigt bibehålla mekanisk prestanda utan kostnadsökning.
<div class="section abstract"><div class="htmlview paragraph">Although propulsion noise often constitutes a minority of the overall noise in electric vehicles, it remains an important quality indicator due to its high-frequency tonal character, which is undesirable even at low levels.</div><div class="htmlview paragraph">There are many factors that influence the interior car levels of propulsion noise, i.e. gear whine and electric motor whine. The primary ones to consider are the electric drive units (EDU) internal forces, but also secondary properties such as EDU housing design and encapsulation, vehicle sound pack and mount isolation play important roles.</div><div class="htmlview paragraph">This work focuses on EDU housing design and more particularly on the housing ribs that enables attachment point stiffness and housing strength, but which can also cause problems in terms of noise radiation. Numerical parameter studies on geometrical properties such as length dimensions, thickness and curvature were performed on single ribs of different types. For each design iteration, the key performance indicators radiated sound power, squared velocity and radiation efficiency were studied.</div><div class="htmlview paragraph">The outcome of this work provides insights into which characteristics of ribs that are central for radiated noise. For instance, it was proven that a rather small curvature of the outer edge of a rib can decrease the radiated noise but also that certain rib dimensions can result in extensive noise due to the interaction of the first bending mode with the peak in radiation efficiency.</div></div>