Squeal Stopper
Brakes-even new ones-are plagued with the problem of squeal, a major cause of consumer complaint and warranty repairs. The exact cause is unclear, but according to one theory, the rotor and pads vibrate from the friction of rubbing together, creating a high-pitched screech that squeal suppression tactics such as replacing the pads don’t always cure. Ken Cunefare, a mechanical engineer at the Georgia Institute of Technology, says he has a better solution: a small cylinder housed inside each brake piston. The device holds several layers of a piezoceramic material that stretches when a voltage is applied across it. Every time the driver hits the brakes, a varying voltage is applied to the device, and the material grows or shrinks a few hundredths of a millimeter-changing the force with which it presses against the steel plate on the back of the brake pad. The pulsing pressure causes the brake to vibrate at a higher, inaudible frequency. Cunefare has done lab tests and is looking for a corporate partner to help him build a second-generation prototype that he could road-test on cars.
Keep Reading
Most Popular
Large language models can do jaw-dropping things. But nobody knows exactly why.
And that's a problem. Figuring it out is one of the biggest scientific puzzles of our time and a crucial step towards controlling more powerful future models.
The problem with plug-in hybrids? Their drivers.
Plug-in hybrids are often sold as a transition to EVs, but new data from Europe shows we’re still underestimating the emissions they produce.
Google DeepMind’s new generative model makes Super Mario–like games from scratch
Genie learns how to control games by watching hours and hours of video. It could help train next-gen robots too.
How scientists traced a mysterious covid case back to six toilets
When wastewater surveillance turns into a hunt for a single infected individual, the ethics get tricky.
Stay connected
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.