How EVs Challenge Bushing Suppliers To Keep Things Quiet

JUL 3 2018 BY VANJA KLJAIC 8

The near-silent electric vehicles are pushing manufacturers of bushings to take another evolutionary step in their business

Tenneco, a multi-national corporation with 93 manufacturing facilities in 26 countries, predicts over half of its future ride-performance business is resting in the hands of electric vehicles. In turn, they’ve made their subbrand Clevite, a pioneer in the field of NVH (Noise, Vibration, and Harshness), move ahead in evolutionary work to reduce noise, vibration and harshness in EVs. Now, accelerated development programs are calling for help.

“This business could transform how suspensions are done,” Tenneco Chief Technology Officer Ben Patel says during an R&D center lab tour in northern Ohio. “This is 15% to 20% of what we do on its way to half” of the supplier’s ride-and-handling business.

For Clevite, the last surviving brand of the former Pullman Palace Car Company, diving deep into making EV vehicles quiet seems like a logical step forward. With nearly every major passenger and commercial vehicle using Clevite products to offset NVH issues, it’s safe to assume that the near-silent electric vehicles will bring forth another round of evolutionary enhancements to this often neglected, albeit important, motoring engineering field.

“We didn’t have to learn how to be an engineered elastomer firm,” says Joe Cerri, who works in NVH products and technologies. “We had the tools in place.”

For Tenneco, their profound knowledge in engineering & design of rubber used in suspension bushings, mounts, and subframes, allowed them to easily adapt to particular requirements of EVs. In January, Tenneco revealed that the company will supply Daimler Trucks North America with spring eye bushings, slated for their Freightliner Cascadia Class 8 tractors. This month, Daimler announced an all-electric version of their flagship heavy-duty truck.

“Masking noise and vibration has allowed us to help (customers) build a vehicle that’s quiet,” Cerri says. “In the past, there wasn’t that level of sensitivity because you had an internal-combustion engine that was doing its thing and vibrating. That’s no longer present.

In the consumer grade electric vehicle market, there are several NVH challenges the company needs to overcome. These include engineering different top mounts and suspension bushings, as EVs are particularly sensitive to high-frequency noises. While the total combined mass of an ICE (Internal Combustion Engine) vehicle and an electric vehicle may be the same, the different distribution of said mass poses a particular set of challenges.

“The fact that they have to package (EVs) for that battery pack makes for geometry changes,” Cerri says. “For example, we ended up with shorter links that drive high articulation angles” supporting the vehicle knuckles. “Low-mass components can save the mass for drive units and battery packs.”

Furthermore, making the inner and outer bushing sleeves from aluminum or engineered plastic – instead of steel  – could help EV manufacturers save 30% to 40% in mass, he says. While this is an often neglected field, the near-silent electric vehicles will bring forth a need to make even these items to a higher standard, producing a more comfortable driving experience.

Source: Wards Auto

Categories: General

Tags: , , ,

Leave a Reply

8 Comments on "How EVs Challenge Bushing Suppliers To Keep Things Quiet"

newest oldest most voted
Tim Miser

How can you hear bushings over the loud roar of tires on pavement?

F150 Brian

It’s about the isolation of bumps from the passenger compartment. In an ICE, there is enough white noise from the tires + engine mechanics + intake noise + exhaust noise + drivetrain that additional bumps and thuds aren’t so noticeable.
Some people only buy body on frame vehicles for the very same reason.

DamoclesAxe

Because the bushing mounts are tied directly to the chassis of the car?

Magnus H

Depends a lot on the quality of pavement and the tires.

Heisenberght 3.0

Yet another thing that comes up. Soon we will read about tire manufacturers producing silent tires.

Coupled with autonomous driving those 2025 cars will be a comfy and silent place to take a nap.

Michael

I think the rubber bushings also dry out faster on an EV since they aren’t bathed in a fine mist of engine oil. That’s my theory anyways. The bushings on my 2015 LEAF creak in the summer until I drive through a puddle for a lubricating bottom blast.

Heisenberght 3.0

Yeah! That fine mist of engine oil is a good protection against rubber drying and rusty metal… My 1990 Fiat Ducato is a nice example for that…

Nonetheless I would prefer to convert it to an EV. Unfortunately I guess I’ll have to wait another 5 years until my budget allows to do that… I’m really hoping that retrofitting will have become a thing by then…

Heisenberght 3.0

Keep things silent. Yes that’s a good thing. The negative impact of noise pollution is often underestimated.

I once talked to a bus driver who was lucky enough to drive an electric bus for some months in a field test. The first thing he mentioned was that his work was now more relaxing because it was more silent. Also the passengers wouldn’t shout at each other while having a conversation.

I am also quite optimistic that reducing the noise induced stress level in daily traffic will have a positive impact on drivers behavior, blood pressure and mental health. Relax. Just do it.