Vibracoustic addressing NVH challenges in EVs

Sometimes, the best solution is a quieter one, a smoother one.

Vibracoustic S.E., a global manufacturer of noise, vibration and harshness products, is developing those kinds of solutions with its rubber-based decoupling products that are designed to help auto makers manage emerging noise and vibration challenges. The newest NVH challenges come from auxiliary systems—such as coolers, pumps and compressors—that are no longer belt-driven in e-mobility applications.

Vibracoustic's decoupling solutions—made primarily of rubber—consider vehicle NVH needs and include the option for single- or double-isolation layers, according to Hans Windahl, vice president of Vibracoustic's global application team for isolators and dampers. A double-isolated bracket was used for a vacuum pump for the braking system of a standard C-segment vehicle to eliminate unwanted noises of the braking system. While these NVH issues had no impact on the performance of the vehicle's braking system, many customers would perceive this as a critical safety issue or attribute it to poor quality.

"These solutions address an NVH issue, which is primarily seen in EVs as the masking noises and vibrations of (internal combustion) engines are no longer present in electric vehicles," Windahl said.

All products manufactured by Vibracoustic, including these decoupling solutions, are made specifically for customer requirements, which includes different OEM vehicle makes and models. Without identifying its OEM customers, Vibracoustic noted it works with 19 of the top 20 light vehicle manufacturers and has a presence in 18 countries.

These single- and double-isolation layer decoupling solutions also can help mitigate other unwanted noises that also could occur in ICE vehicles, but Vibracoustic chose to focus on the unique challenges presented by EVs. With this aim, Vibracoustic anticipated the NVH issues specific to electric vehicles and researched ways to address them in a cost-effective and efficient way, Windahl said.

"We are in discussions with various OEMs and already have (these types of) decoupling solutions," he said. For example, Windahl added, the vacuum pump double-isolation decoupling is in mass production for inclusion in a high-volume compact car.

In testing these decoupling solutions, Vibracoustic uses a holistic approach, closely collaborating with the engineering departments of its customers at each stage of the development process. Once component specifications and requirements—like installation space, life span, mounting points, static and dynamic loads, driving characteristics and the DNA of each vehicle—are defined, engineers develop the part design using computer-aided engineering.

This process allows Vibracoustic team members to precisely predict the performance of each component over its lifespan, on all platforms and all drive concepts.

"Once we have defined the part design via CAE and have chosen the right material mixing family, we manufacture prototypes of our components for validation before serial production," Windahl said. "Addressing real-world requirements in our testing ensures correct remeasurements and the precise updating of parameters. Our testing and simulation efforts always result in the optimal design and performance of the NVH component."

The experimental and virtual validation and testing of prototypes are designed to ensure that solutions meet the NVH performance criteria of Vibra- coustic's customers, allowing its team to adjust the geometries of the component if necessary.

Vibracoustic engineers also have developed decoupling solutions for eCompressors—electronically powered compressors that are used in EVs for requirements such as air conditioning and battery cooling. By analyzing the excitations, the engineers were able to develop a specifically tuned mounting concept, which, in combination with optimized brackets, is combined into a mounting assembly and produced with cost efficiency in mind.

The benefit to EV OEMs is that these eCompressors will eliminate vibrations and noise generated internally, minimizing the vibration level for particularly sensitive conditions, such as during high-voltage fast charging.

In late 2020, Vibracoustic launched an eCompressor decoupling solution that fits battery-electric and plug-in hybrid vehicles. The goal was to balance thermal management with excessive noise and vibration.

Following extensive testing and simulation processes of the entire mounting system, Vibracoustic designed, developed, and manufactured a bracket and mounting assembly that eliminated internal noise and vibrations during motion, as well as minimizing compressor noise while stationary during fast charging.

These solutions are manufactured in multiple locations globally, including the U.S., parts of Europe and China.

Vibracoustic, part of the Freudenberg & Co. K.G. family, posted sales of around $2.05 billion in 2020 and holds an NVH market share of about 20 percent, according to Windahl.

The company employs more than 10,000 globally and operates 18 R&D sites as part of its 41 locations.