SoylentNews is people
SoylentNews
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: 4, Insightful) by sjames on Thursday May 12 2022, @02:23AM (7 children)
My concern is that the 'brakes' will have practically no holding power on a hill. Creeping back until you tap the car behind you is a problem.
(Score: 2) by RS3 on Thursday May 12 2022, @02:34AM (1 child)
(sarcasm:) Naaa, they'll apply battery power to hold you on the hill. What could possibly go wrong?
Even if your battery dies, or electronic problems, by then cars will have nice thick rubber bumper perimeters, much like bumper cars, but softer. So you can roll back. No more damages and wasteful insurance money spent. (/sarcasm...)
(Score: 3, Funny) by sjames on Friday May 13 2022, @12:45AM
Now I have "Red Barchetta" running through my head.
(Score: 1) by anubi on Thursday May 12 2022, @06:53AM (1 child)
That is a good concern!
If energy is not expended to hold the vehicle stationary, like a Segway, what you say is exactly what will happen once you overcome the hysteretic magnetic field and static friction of the motor bearings.
If it wasn't for friction and hysteresis, this system would approach a stop asymptotically, and never get there.
In the case of the wire bonder, friction did the job.
Agreed, there must be mechanical takeover to maintain stop once an active ( powered ) stop has been attained. Actively maintaining stop will require significant energy.
For stop and go traffic, an active stop is probably ok, but we are definitely going to need a mechanical Park mode. Without some sort of mechanical " wheel chocks ", the car will most definitely roll down the hill.
Thanks for bringing that up.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 3, Interesting) by sjames on Friday May 13 2022, @12:28AM
Yes. That might be a fairly complex system to be both effective and reasonably fail resistant. I'm not so sure anything beyond press the brake pedal a little harder will really work. That means the friction brakes will still need to be able to handle being activated when the car is still moving (and we're still stuck with anti-lock mechanisms).
That isn't to say that I oppose augmenting existing regenerative braking to handle more, including where practical bringing the car to a complete stop. I just don't want to see bumper cars out there.
I think it's a real concern in the wake of more than one manufacturer replacing the cable actuated emergency brake (which I have needed on 2 occasions) with an electrically actuated "parking brake" that has two states: free wheeling and lock-'em-up.
(Score: 0) by Anonymous Coward on Thursday May 12 2022, @12:55PM (2 children)
Yes, but you also have the Parking Brake thing that will have to remain and be purely mechanical for many reasons. The stopped car on a hill could as well use this too or maybe a combination of the two. The point is,
1. EM brake would reduce the need brake replacements
2. and no more thousands of tons of brake dust in the air to breath -- that's probably a good thing?
3. holding something stationary needs a lot smaller brakes than making it stop from 100km/h and also see #1
(Score: 2) by sjames on Friday May 13 2022, @12:38AM (1 child)
I'm not so sure drivers will remember or even know to apply a parking brake to stop in traffic. In all likelihood, there will still need to be a friction brake tied to the action of pressing the brake pedal. We can and should have regenerative brakes (common on hybrids and electric vehicles now) and it's great if we can make the regenerative phase of braking to a stop longer and more effective. But not having friction brakes at all as implied in TFA is out of the question.
It's worth noting that more than one manufacturer has replaced cable actuated emergenmcy brakes with electrically actuated "parking brakes" that are worthless for bringing a car to a controlled stop in an emergency.
(Score: 0) by Anonymous Coward on Friday May 13 2022, @10:00AM
"It's worth noting that more than one manufacturer has replaced cable actuated emergenmcy brakes with electrically actuated "parking brakes" that are worthless for bringing a car to a controlled stop in an emergency."
Others here seem to have a really good approach...a two stage system...where a light to medium braking is regenerative, a harder braking reverts back to existing hydraulics.
I can see a parking pawl. I have one on my automatic transmission. Like you say, useless for a controlled stop. But once stopped, it locks the drive shaft.
I'd much rather my engine fail than my brakes fail. I will still drive my machine with a flakey engine, but if it's brakes are acting up, it gets towed.