DS E Tense Performance Concept Thinks Future Cars Won’t Have Brakes

[cawimmer430]

DS E Tense Performance Concept Thinks Future Cars Won't Have Brakes

DS Automobiles' latest concept car asks us to imagine a future world where cars don't have brakes.

Obviously the DS E Tense Performance is capable of slowing down, but it does it without the conventional braking systems we all know and trust. Instead of a regular set of disc brakes, it relies exclusively on regenerative braking technology to regulate its speed.



And there's plenty of speed to regulate. The E Tense Performance was developed with DS's Formula E team and employs the exact same electric motors that are fitted to the singe-seat racers. That gives the two-door coupe 804 hp (815 PS) plus a spectacular 5,900 lb-ft (8,000 Nm) of torque, and the ability to accelerate from 0-62 mph (0-100 km/h) in 2.0 seconds. Make use of the 350 kW charging tech and you can fill the battery in just five minutes.

Regenerative braking is nothing new. It's commonly found on electric and hybrid vehicles, but is always used in addition to traditional disc brakes. DS Automobiles, though, is looking further in the future and exploring the idea of doing away with conventional rotors and hydraulic calipers. The advantages to such a setup include a weight reduction from getting rid of heavy disc brake hardware (which on most cars usually include steel, rather than lighter carbon rotors).



But harnessing all of the braking energy, rather than letting it go to waste as heat generated from the friction of the pads pushing on discs, is great for efficiency too, because it can be channeled back into charging the battery.

"Formula E is about maximizing performance and efficiency, and the DS E Tense Performance is our vision of a road car utilizing our race-winning technology," said Beatrice Foucher, DS Automobiles CEO. "Regenerative braking is a very powerful way to not only slow the vehicle down, but also help improve battery performance. The DS E Tense Performance takes the technology to a new level, with regenerative braking used solely to slow the vehicle down."






Link: https://www.carscoops.com/2022/05/ds-e-tense-performance-concept-thinks-future-cars-wont-have-brakes/

[NomisR]

The battery would have to have excess unused capacity to take the charge when the battery is "full" otherwise, this wouldn't work.  Since when the battery is full, the regenerative braking is typically reduced since the car can't take anymore charge.

[Soup DeVille]

Not driving a car without real brakes, no matter how good the regenerative brakes are.

Failures happen, and regenerative braking is limited as to how much power it can absorb at once- and what happens when the battery capacity is reached? will it vent excess heat via resistor banks? At that point, its doing the same thing real brakes do, just a lot more complicated.

[FoMoJo]

I haven't looked into it, but do regenerative braking systems have parts that wear out, like brake pads?

If regenerative braking is able to stop with the same reliability as disc brakes, perhaps it will mean one less maintenance cost when pads wear out, as well as discs.

[giant_mtb]

No thanks.

[Morris Minor]

The battery would have to have excess unused capacity to take the charge when the battery is "full" otherwise, this wouldn't work.  Since when the battery is full, the regenerative braking is typically reduced since the car can't take anymore charge.

If the battery is fully charged, one possibility is rheostatic braking: dissipating the excess energy as heat in a resistor. That heat could possibly be used for something like warming the cabin, or just vented to the air with fans.


Edit: https://eepower.com/resistor-guide/resistor-applications/braking-resistor/#

[NomisR]

If the battery is fully charged, one possibility is rheostatic braking: dissipating the excess energy as heat in a resistor. That heat could possibly be used for something like warming the cabin, or just vented to the air with fans.


Edit: https://eepower.com/resistor-guide/resistor-applications/braking-resistor/#

It seems that this type of system is most effective in low temperature settings to get maximum efficiency.. i'm wondering how well it would work in places that has 100+ degree summers.

[SJ_GTI]

I think I saw that VW is just putting rear drum brakes on their new van. The thinking is that the regenerative braking will do most of the work and the drums would only be used occasionally and should last the life of the vehicle. I think this makes sense as you have the regeneration there for efficiency and a cheap, cost effective mechanical brake just the few situations where they might help. Plus no brake dust. 

[NomisR]

I think I saw that VW is just putting rear drum brakes on their new van. The thinking is that the regenerative braking will do most of the work and the drums would only be used occasionally and should last the life of the vehicle. I think this makes sense as you have the regeneration there for efficiency and a cheap, cost effective mechanical brake just the few situations where they might help. Plus no brake dust. 

Eh, I got a shit ton of brake dust on my rear wheels.. none in front though.  And apparently it's pretty normal for the Brembo brakes on the performance model especially if you have aftermarket pads.

[Morris Minor]

I think I saw that VW is just putting rear drum brakes on their new van. The thinking is that the regenerative braking will do most of the work and the drums would only be used occasionally and should last the life of the vehicle. I think this makes sense as you have the regeneration there for efficiency and a cheap, cost effective mechanical brake just the few situations where they might help. Plus no brake dust. 

Friction brakes, since they're in a secondary (or even tertiary) role, could at least be downsized: saving weight is good, saving unsprung weight is great.

When I had a drive of my neighbor's Model 3, it took about six miles for me to get used to one pedal using the car's "hold" stopping mode option. It's an easy transition.

[Laconian]

You could mine bitcoins with the surplus energy. Stop and go in traffic becomes an NFT goldmine. Such innovation, wow

[CaminoRacer]

My Bolt has 100k miles on the original brake pads.

I still want real brakes.

[r0tor]

Formula E is ditching brakes on I believe 1 axel on their cars next year... Seems like a pragmatic approach

[FoMoJo]

My Bolt has 100k miles on the original brake pads.

I still want real brakes.

Electrically activated are they?

[Eye of the Tiger]

Formula E is ditching brakes on I believe 1 axel on their cars next year... Seems like a pragmatic approach

The rear?

[NomisR]

Electrically activated are they?

There's multiple ways, lift to brake/regen which works like engine braking with a manual on 2nd or 3rd gear.  Flap on the steering wheel to increase the regen braking, I don't like this one because it's harder to control how much you want to slow down.  And then there's the brakes pedal which is a mix of regen braking and then transition to the standard brakes when you need more.  I like the way Chevy does it the most because their transition between regen braking and physical brakes is pretty seamless.

[giant_mtb]

How good can a regen brake be in an emergency stop situation?

[Soup DeVille]

How good can a regen brake be in an emergency stop situation?

Essentially, they can brake only as hard as they can accelerate. The capacity of the inverter and motors to generate power (regen brake) is essentially the same as their ability use power.

I mean, that's an oversimplification because the inverters are often programmed with different power limits or accel/decel functions, but its not going to vary a lot.

[giant_mtb]

Essentially, they can brake only as hard as they can accelerate. The capacity of the inverter and motors to generate power (regen brake) is essentially the same as their ability use power.

I mean, that's an oversimplification because the inverters are often programmed with different power limits or accel/decel functions, but its not going to vary a lot.

So essentially/theoretically, if an electric car can do 0-60mph in 4 seconds, its maximum braking potential would be 60-0mph in 4 seconds (other variables notwithstanding)? 

[r0tor]

The rear?

pretty sure

[CaminoRacer]

Essentially, they can brake only as hard as they can accelerate. The capacity of the inverter and motors to generate power (regen brake) is essentially the same as their ability use power.

I mean, that's an oversimplification because the inverters are often programmed with different power limits or accel/decel functions, but its not going to vary a lot.

Bolt is limited to around 70 kW regen, vs ~150 kW allowed during acceleration.

But that's due to limitations imposed by the engineers to protect the electrical systems and improve longevity.

So essentially/theoretically, if an electric car can do 0-60mph in 4 seconds, its maximum braking potential would be 60-0mph in 4 seconds (other variables notwithstanding)? 

If the software allows max regen, yes. Although due to friction, drag, etc, the time to stop will be lower than the time to accelerate if the system allows the same max kW for acceleration and regen.

[Soup DeVille]

So essentially/theoretically, if an electric car can do 0-60mph in 4 seconds, its maximum braking potential would be 60-0mph in 4 seconds (other variables notwithstanding)? 

Yes, but there are variables.

The inverters could already be hot from accelerating, and incapable of maximum power transfer for instance.

[CaminoRacer]

The regen does taper off pretty quickly, too. Doesn't work nearly as much at slower speeds.