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No more brakes for cars of the future:
Electric cars of the future could be able to ditch conventional brake technology in favour of powerful regeneration by battery-powered motors.
[...] Electric cars already use a combination of conventional friction braking and brake regeneration. The latter slows down vehicles using resistance from the same electric motor that propels the car, feeding that energy into the car's battery to extend its range.
DS, Citroen's luxury arm, said it is "exploring whether regenerative braking alone could eventually be the sole method to slow cars down, helping to better recharge the battery in the process, and doing away with conventional brake discs and pads".
[...] [Conventional brake pads and drums] produce "brake dust", fine particles of metallic material that separates from the pad and disc as part of the braking process.
[...] Dr Asma Beji, a non-exhaust particles expert, said in June 2021 that "the impact on health of brake wear particles is undeniable and cannot be neglected".
[...] Environmental researcher Dr Liza Selley, published a paper for the MRC Centre for Environment and Health at King's College London and Imperial College London in 2020 that suggested "diesel fumes and brake dust appear to be as bad as each other in terms of toxicity in macrophages".
[...] "Macrophages protect the lung from microbes and infections and regulate inflammation, but we found that when they're exposed to brake dust they can no longer take up bacteria.
"Worryingly, this means that brake dust could be contributing to what I call 'London throat' – the constant froggy feeling and string of coughs and colds that city dwellers endure – and more serious infections like pneumonia or bronchitis which we already know to be influenced by diesel exhaust exposure."
DS and other manufacturers including Jaguar and Porsche participate in Formula E electric car racing. The series will eliminate rear disc brakes from its next-generation machines in a bid to improve real-world research into the performance potential of purely regenerative braking.
(Score: 3, Informative) by mcgrew on Thursday May 12 2022, @09:14PM (2 children)
For instance, I'm heading down a road at around 45 mph on a snowy day, come round a corner, and there's a construction zone and completely stopped traffic, and the fact that I was able to basically override any computers that thought they knew better to stop quickly made a world of difference.
I was a driver in the Air Force, and they train you for emergency braking. I was incredibly surprised by the last car I had with ABS; it could stop on ice faster than I could. On a slippery surface, it doesn't matter if you have drum brakes on a 14 inch wheel or 4 disks on a 16 inch wheel, they'll both stop in the same distance. When it's slick, the power of the brakes doesn't matter at all, preventing the wheels from locking does.
mcgrewbooks.com mcgrew.info nooze.org
(Score: 1) by pTamok on Friday May 13 2022, @07:28AM (1 child)
One situation where ABS gives a longer stop distance than conventional lock-up-and-pray braking is where you are on loose, friable surfaces, such as snow, or pea-gravel. This is because, if the wheels are locked up, the snow (or gravel) piles up in front of the wheels, whereas ABS aims to keep the wheels turning at a rate just before locking up to provide maximum retardation.
Drivers used to be taught to 'pump' the brakes when needing to stop in a hurry, so that if you locked up and started sliding, reducing the brake pressure would allow the wheels to start rotating again, providing control (sliding locked-up wheels have no steering, they simply slide in the direction the car is going and provide no sideways force to turn), and allowing for more retardation (on average) than locked up wheels. It's a hard technique to learn and apply in 'panic' situations. ABS simply automates brake pumping, does it faster than humans can, and monitors the wheel rotation rate to ensure it doesn't drop to zero. If you see the black stripes on a road surface where someone has braked hard, you can see a locked up brake as a continuous black stripe, whereas ABS either leaves no stripe, or a non-contiguous strip - a dashed black line. ABS has far better performance than humans on ice as it actively monitors each wheel's rotation to ensure it doesn't lock up.
(Score: 2) by mcgrew on Friday May 20 2022, @12:49AM
The ABS' main advantage isn't stopping more quickly, although that is an advantage. Without ABS, if your brakes are locked up you can't steer no matter the surface. ABS allows you to steer out of the circumstances that require ABS.
mcgrewbooks.com mcgrew.info nooze.org