Electric vehicles are often praised for their near-silent operation, yet many drivers are familiar with the subtle humming, whistling and high-frequency sounds generated by electric drivetrains and power electronics. Researchers in Germany believe they have found an unexpected way to make future EVs even quieter—by using material recovered from worn-out vehicle tyres.
A research team at Otto von Guericke University Magdeburg has developed a vibration-damping technology that uses granulated recycled tyre rubber to absorb noise-producing vibrations inside electric vehicle components. The approach not only improves acoustic comfort but could also create a new high-value application for millions of tyres reaching the end of their service life each year.
Giving Old Tyres a New Purpose
Unlike conventional vehicles, electric cars produce far less engine noise, making other sounds more noticeable to occupants. Components such as inverters, converters and power electronics can generate vibrations that translate into audible tones, particularly at higher frequencies.
Traditionally, manufacturers have addressed these issues using insulation materials and sound-absorbing mats. While effective, these solutions increase weight and add complexity to vehicle design.
The Magdeburg researchers pursued a different strategy. Instead of blocking sound after it is generated, they focused on preventing vibrations from developing in the first place.
Their solution involves filling existing cavities within electronic components with specially engineered particles made from recycled tyre rubber. As vibrations occur, the particles move and interact with one another, dissipating energy before it can be converted into noise.
Significant Noise Reduction in Laboratory Tests
Testing showed that the particle-based system can substantially reduce both vibration and sound levels in critical operating ranges.
According to the research team, the technology lowered noise levels by up to 6.5 decibels while reducing vibration amplitudes by as much as 9.7 decibels on selected component surfaces.
Because the damping material can be integrated into unused spaces already present within electronic housings, the system requires minimal structural modification and adds little additional weight.
Researchers say this could make the technology attractive for future electric vehicle platforms where efficiency, packaging space and cost remain key design priorities.
More Than a Simple Filling Material
Developing the system proved more complex than simply inserting rubber particles into a component.
The effectiveness of the damping process depends on multiple variables, including particle size, quantity, temperature, component geometry and vibration frequency.
“Particles behave very differently depending on their size, material, filling quantity, temperature, component geometry, and excitation. That’s why simply filling a component with granulate isn’t enough. We must calculate and test which particles, in what quantity and at which location, achieve the best results,” explained Dr.-Ing. Braj Bhushan Prasad.
The team is now developing predictive design tools that could help engineers determine the optimal particle configuration for specific vehicle applications.
A New Approach to EV Refinement
Researchers believe the technology could eventually be used across a broad range of electric vehicle systems, including power electronics, inverters, control modules and other components susceptible to vibration-induced noise.
Beyond improving passenger comfort, the approach also supports sustainability objectives by creating a new use for recycled tyre materials.
“Our findings show that even small particles made from recycled tyre rubber can make a noticeable difference in reducing noise in electric vehicles,” said Professor Hermann Rottengruber.
“We now aim to develop this into a tool for designing future electric vehicles, so they not only drive cleaner but also sound more pleasant.”
As electric vehicles continue to evolve, reducing unwanted electronic noise is becoming an increasingly important aspect of vehicle refinement. The researchers’ work suggests that one of the industry’s future solutions may come not from new materials, but from finding innovative ways to reuse existing ones.
Source: EVMagz