NVH-Fighting Plastic EV Motor Mount Wins Lightweighting Award

The mount, made from a new version of Zytel, is particularly adept at damping the high-frequency vibrations electric motors are known for.

The electric drive motor mount for the Cadillac Lyriq uses Zytel PA 66, a new formula that has impressive structural strength for the amount of NVH damping it provides. (SAE/Chris Clonts)

Most motor mounts, even for EV applications, are made of metal alloys. It makes intuitive sense: It’s a vibration-intensive mounting application that demands durability that matches the life of the vehicle itself. But there is another way. Now, a composite nylon-based motor mount on the Cadillac Lyriq has won the Society for Automotive Analysts’ Innovation in Lightweighting Award.

Celanese Global Marketing Manager Gabriel Knee said the winning EV motor mount has as much lifetime structural integrity as a metal version but dampens the high-frequency vibrations that are problematic in electric motors. (SAE/Chris Clonts)

The mount is a collaboration between GM, anti-vibration parts maker DN Automotive and chemical company Celanese. It is made with Zytel PA NVH Gen 2, a new polyamide (PA 66). The results not only showed up in development data, but in the end product, which has reviewers raving about how quiet the Lyriq’s cabin is — “crypt quiet,” according to Automotive News.

Gabriel Knee, global marketing manager of engineered materials for Celanese, said that almost all discussions at his company talk about using “the right material for the right location and the right application. He still had a sense of wonder when he summarized the part again. “This is, you know, a plastic mount that's being used on the main drive motor of the Lyriq. So when you think of the electric motor, and the amount of torque that goes through that, it's a pretty phenomenal amount of mechanical strength that's required there. So it’s a really innovative material.”

Knee said that mount is made from the polymer, which is filled 35% with glass, and not only saves 30% of the weight of an alternative standard metal motor mount, but it also eliminates the need for several other components (primary mass dampers) in the vehicle. This also reduces costs. And, of course, it offers the mechanical strength to last through the end of the vehicle’s life. Knee said improvements were the key to Cadillac’s adoption of the part. “One thing I did not realize was within the electric vehicle, you're dealing with much higher frequency noises and, to damp those high frequency noises, it turns out that this material is ideal,” he said. “At lower frequencies, there's not much damping at all. But the higher frequencies are where it's much more effective. So, it really tailors itself to this application.”

Knee also said that, unlike some composites, the structural integrity is maintained across a wide range of ambient temperatures. He pointed out that the base material had been around for more than a decade and had been used for all manner of NVH applications. But it had always sacrificed strength to meet each use case’s vibration damping goals.

Lindsay Brooke, former editor of Automotive Engineering and one of three judges for the competition, lauded the partnership’s work on the mount. “Celanese and Cadillac engineers have brought an elegantly simple solution to the multiple challenges of EV lightweighting, NVH abatement and cost reduction,” he said. “Zytel PA66 is once again the workhorse material for this vehicle application, proving its ever-widening scope.”

Dave Andrea, a supplier-relations partner at Plante Moran and a judge, said the primary factors the judges considered were:

  • Technical complexity. “Was it a reuse of an existing material or existing process? They just found it a new home? Or was it truly something innovative?”
  • Total savings of the product. Just saying lightweighting wasn’t enough, Andrea said: “We had some entries that came close to a 40 percent cost reduction.”Overall parts reduction, which the Celanese entry had in its favor.
  • Scalability. “Could this really impact the whole industry,” he said.
  • Serviceability. For instance, a gigacasting solves complexity, but can it be serviced? “You have to think about the total lifecycle of that product, not just at the moment it leaves the assembly plant,” he said.Abhay Vadhavkar, a retired engineering director now consulting for Envorso, was the third judge on the panel.
Plante Moran’s Dave Andrea, left, and independent engineering consultant Abhay Vadhavkar, joined former Automotive Engineering editor Lindsay Brooke (not pictured) on the judging panel. (SAE/Chris Clonts)

Another Celanese project won an honorable mention: a Zytel-based air-conditioning compressor bracket being used on the Ford Mustang Mach-E. Other innovations earning honorable mention were:

  • Meridian Lightweight Technologies | Ford Mustang Shelby GT500 Magnesium Strut Tower
  • Teijin Automotive Technologies | Hexacore Class A Body Panel process
  • IRMCO | New sustainable lubricant
  • Mubea CarboTech | Composite underbody protection system
  • eLeapPower | In
  • Plasma Bound | CPA surface preparation technology
  • Bocar | Toyota Tunda rear-end post

Abey Abraham, SAA chairman and principal at Ducker Carlisle, said the award is an important marker for companies that don’t let institutional momentum prevent innovation. “As an industry, we have been forced to think out of the box, be collaborative and put aside the notion of ‘that is always how we’ve done it.’ Mobility is evolving quickly and vehicle lightweighting is a critical part of that evolution. These entries showed that we are ready for that evolution.”