Audi Says Regen Braking Of e-tron Boosts Range By Up To 30%

AUG 9 2018 BY MARK KANE 54

The presence of Audi e-tron prototypes in Colorado was not accidental, as the German manufacturer has now announced that it tested regenerative braking at Pikes Peak.

The four Audi e-tron prototypes demonstrated high-efficiency regenerative braking that involves both the two electric motors (one per axle) and the electrohydraulically integrated brake control system.

According to Audi, regenerative braking can extend the range by up to 30%. The peak power generation is 220 kW with braking torque of 300 Nm, which is around 70% of peak driving power (300 kW).

In the case of the Pikes Peak downhill of over 19 miles (31 km), the e-tron was able to add 1 mile of range per each mile of driving down. And in the end, the brakes were cold, because the e-tron uses electric motors for braking as much as possible. There are also other regenerative braking modes, including coasting.

Additionally, braking distance is reduced by up to 20% thanks to regen, compared to a conventional SUV.

“The recuperation concept: from freewheeling to a one-pedal feeling

The Audi e-tron prototype on recuperation test at Pikes Peak

The recuperation system contributes to up to 30 percent of the electric SUV’s range. It involves both the two electric motors and the electrohydraulically integrated brake control system. For the first time, three different recuperation modes are combined: manual coasting recuperation using the shift paddles, automatic coasting recuperation via the predictive efficiency assist, and brake recuperation with smooth transition between electric and hydraulic deceleration. Up to 0.3 g, the Audi e-tron prototype recuperates energy solely via the electric motors, without using the conventional brake – that covers over 90 percent of all decelerations. As a result, energy is fed back to the battery in practically all normal braking maneuvers.

The driver can select the degree of coasting recuperation in three stages using the steering wheel paddles. At the lowest stage, the vehicle coasts with no additional drag torque when the driver releases the accelerator pedal. At the highest stage, the electric SUV reduces the speed noticeably – the driver can slow down and accelerate using only the accelerator pedal. This creates the one-pedal feeling. There is no need to use the brake pedal in this deceleration scenario.

The Audi e-tron prototype on recuperation test at Pikes Peak

The wheel brakes are involved only when the driver decelerates by more than 0.3 g using the brake pedal. They respond extremely quickly, thanks to a new electrohydraulic actuation concept. Audi is the first manufacturer worldwide to use this concept in a series production vehicle with electric drive. A hydraulic piston in the compact brake module generates additional pressure and thus additional brake force for the recuperation torque. When automated emergency braking is performed, there are only 150 milliseconds between the initiation of the deceleration and the presence of maximum brake pressure between the pads and disks. Thanks to this rapid pressure buildup, the braking distance is shortened by up to 20 percent compared with a conventional brake system.

Depending on the driving situation, the electrohydraulically integrated brake control system decides – electrically on each individual axle – whether the Audi e-tron prototype will decelerate using the electric motor, the wheel brake, or a combination of the two. The brake pedal is decoupled from the hydraulic system. The transition from the engine brake to the pure friction brake is smooth, and the driver does not notice it. This system allows the electric SUV to exploit its maximum recuperation potential in a targeted manner with support from the standard efficiency assist. The system uses radar sensors, camera images, navigation data and Car-to-X information to detect the traffic environment and the route. The driver is shown corresponding information in the Audi virtual cockpit as soon as it would be sensible to take the foot off the accelerator pedal. By interacting with the optional adaptive cruise assist, the efficiency assist can also decelerate and accelerate the electric SUV predictively.”

The other interesting new feature is the special S mode (boost mode) in addition to the normal D (drive mode). D offers up to 265 kW and 561 Nm of torque for up to 60 seconds – enough to reach top speed of 200 km/h (124.3 mph) several times. For best acceleration (0-62 mph blow 6 seconds) there is S mode, which for eight seconds can provide up to 300 kW of power and 664 Nm of torque.

The Audi e-tron prototype on recuperation test at Pikes Peak

“The asynchronous motors: strong performance
What is fascinating about the SUV with electric drive is not just its efficiency but also its performance. Its two electric motors have an output of 265 kW and develop 561 Nm (413.8 lb-ft) of torque. They can deliver this peak performance for up to 60 seconds. This way, they allow the vehicle to accelerate from a standstill to the electronically limited top speed of 200 km/h (124.3 mph) several times consecutively without output losses. The maximum drive torque is present within fractions of a second and provides enormous torque. By shifting from drive range D to S and fully depressing the right-hand pedal, the driver can activate boost mode. It is available for eight seconds. Here, the drive produces 300 kW of system output and 664 Nm (489.7 lb-ft) of torque. The Audi e-tron prototype sprints from 0 to 100 km/h (62.1 mph) in less than six seconds.”

Audi e-tron data:

  • 0 to 100 km/h (62.1 mph) in less than six seconds
  • up to 265 kW and 561 Nm in D mode (peak power for 60 seconds) and up to 300 kW and 664 Nm in S boost mode for eight seconds
  • top speed of 200 km/h (124.3 mph)
  • 400 km (248.5 mi) of range under WLTP
  • regenerative braking: up to 300 Nm of torque (221.3 lb-ft) and 220 kW of electric power – more than 70 percent of its operating energy input
The Audi e-tron prototype on recuperation test at Pikes Peak
47 photos
The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak The Audi e-tron prototype on recuperation test at Pikes Peak

Press blast:

Take charge:
Audi e-tron prototype – recuperation test

  • Highly efficient: up to 30 percent more range thanks to energy recuperation
  • World premiere in electric cars: the electrohydraulically integrated brake control system
  • Strong performance: up to 300 kW and from 0 to 100 km/h (62.1 mph) in less than six seconds

The Audi e-tron prototype on recuperation test at Pikes Peak

The Audi e-tron prototype combines enormous power and high efficiency. With a system output of up to 300 kW, the full-size SUV with a fully electric drive accelerates from zero to 100 km/h (62.1 mph) in less than six seconds. In the WLTP test cycle, it covers more than 400 kilometers (248.5 mi) on one battery charge. One important factor for the long range is the most innovative recuperation concept among the competitors. The electric SUV proved this with an impressive performance at Pikes Peak.

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54 Comments on "Audi Says Regen Braking Of e-tron Boosts Range By Up To 30%"

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CDAVIS

Audi Marking Team:

Welcome to the concept of EV regen braking… and the many other EV benefits over ICE you will become familiar with as Audi transitions to full electric.

Better late than never…

I look forward to Audi eventually getting into production pure EVs… Audi has a reputation of making great high performance cars and would be fantastic to see same quality and performance applied to Audi EVs.

Etain

What they are doing with their regen is totally unprecedented and impressive. Tesla’s regen is usually around 60kW (90kW peak), while this Audi can go up to 220kW. Look at the comments on Electrek’s article about this subject.

There’s also an indication that the charging rate for the battery in the E-tron could be higher than the 150kW we heard about, since the battery seems capable of receiving 220kW of regen power. So at least before tapering, for a period, the charging rate could be as high as 220kW.

David Cary

And the value of that is pretty limited except perhaps on Pike’s Peak. In normal flat land driving, the Tesla regen captures a pretty good amount of the energy. When you try to get more, you run into traction issues in slippery conditions. That is probably the reason that Tesla limits it.

The other issue is that the battery (even Audi’s) is unlikely to be able to take 220 kw when nearly full. So then you have inconsistent braking and off throttle responses at different battery levels. Not saying they can’t overcome that with increased hydraulic braking, not using all of the battery, etc but it is an added level of complexity and cost that has really really marginal benefit.

Etain

It’s not just about Pike’s Peak. It’s useful in flat land driving too for faster braking, not needing to use the brakes as often. And you can choose the level of regen applied, or even let the car sensors adjust the regen power based on road conditions.

And even if it were just a marginal benefit, a marginal benefit is still something, is still better than nothing.

David Cary

Curious – do you have a Tesla and need to hit the breaks?
“better than nothing” – like a roof mounted solar panel? I mean sure, but meaningful and worth the expense – hard to say.

Nono13

Tesla didn’t do it so il must be false or useless. Always the same comments from some Tesla worshippers. Why can’t they just enjoy a world with more EV competition ?

Many say that the bad comments on Tesla are mainly from shorters. Me I wonder if the bad comments on every EV that is not a Tesla are not mainly from Tesla shareholders.

David Cary

Don’t know if that was directed to me but I am just saying that Audi marketing claims are one thing – a real advantage is another.

I am not a shareholder although I have bought some in the past.

Audi is of course famous for EV announcements and no follow through. They are also part of VW group responsible for the largest environmental fraud in the history of the world. So there is that.

But it might be the greatest thing since sliced bread. But I can tell you there isn’t that much lost energy that isn’t already getting recovered. That is just a fact.

Kind A Wierd

Yeah, it was directed at you, and for good reason. I’m curious, where did you get your electrical/mechanical engineering degree from, and how did you manage to get all the tech schematics/data about Audi’s. system?

David Cary

As someone who has been driving EVs for 6 years, the majority of deceleration force is put back into the battery. So I am just saying there isn’t that much left to recover. I never claimed to have details of what Audi is doing and it maybe very effective. But it isn’t going to make that much of a difference in flat land driving.

This is a marketing statement. 30% range increase is a marketing statement.

Tesla decided to take the simple way out and not use the brake pedal for regen. The Leaf does use the brake pedal for regen but it is limited because of battery size and ability to take in energy. So this is an improvement over both.

That is great but when you rarely hit the brakes because of aggressive off pedal regen, there isn’t that much energy to recover.

Shane Smith

As someone who lives near some monster canyons, you misjudged the value.

CDAVIS

@Etain said: “What they [Audi] are doing with their regen is totally unprecedented…”
——————

The more innovation the better… hats off to Audi for pushing the regen boundaries…

Shane Smith

Exactly. And with any luck at all the tech gets to Tesla soon and everyone else adopts it as well.

Pjwood1

They really aren’t aiming for conquest EV customers, if Audi thinks basic hybrid (regen) features are something to familiarize owners with. Granted, 220kw is nice.

VWG has put electrification in a “Greenie” corner before. I hope the focus on regen, instead of the motor-limited power output, does not paint what etron is meant to be.

At near 90KWh, with their chemistry, the battery is probably good for 450KW. Untapped.

Shane Smith

Didn’t even bother to read the article, did ya…

GreenMD

Newton did universal gravitation, Einstein did relativity, and Audi has now discovered regenerative breaking. I hope other automakers can use this scientific breakthrough in their EVs. Oh, wait…
In all seriousness, I’m just glad there are more EVs coming out, no matter how late they are to the party.

R.S

270 kW regenerative braking is a lot, though. Model S and X have about 60 kW.

David Cary

But 270 off throttle would be pretty unbelievably jarring. And they did write 220.

But then they also state .3g. I don’t have the equation in front of me but 220 kw seems like a lot more than .3g. I suppose at 150 mph…..

Kinfeboy

0.3g is 0.3 * 9.81 m/s² deceleration. That’s 2.943 m/s².
Braking from 29.4m/s = 106km/h = 66mph to 0 in 10 seconds or from 33mph to 0 in 5 seconds, which is pretty good braking entirely on regen.

You guys don’t learn that easy stuff at school in 5th grade?

Mark.ca

Who’s “you guys”? The geniuses that skip 5th grade?

David Cary

And did you convert to KW? That is what I was referring to. .3g is certainly decent regen.

antrik

0.3 g is not very jarring — reportedly, some EVs available today can do as much regenerative breaking. The higher power just means it can sustain this at higher speed — up to about 130 km/h, if I did the maths right.

I have no idea though whether the ability to do 0.3 g regenerative breaking at 130 km/h actually matters in practice…

David Cary

.3g not jarring but pretty quick. It was the 220 kw that I was referring to. But like you said – higher speeds.

Hans Blix

Average insideevs comment saying: This is not good as this is not done by Tesla. Otherwise it would be great.

CDAVIS

@Hans Blix said: “Average insideevs comment saying: This is not good as this is not done by Tesla. Otherwise it would be great.”
———

I think you got that backwards…

Most Tesla fans are happy to see other car makers do good things in the EV space… after all it’s Tesla’s clearly stated mission to want other car makers to transition to EVs… to offer exciting compelling EVs in volume production… and to be successful at it.

It’s Tesla that often gets tomatoes thrown at it in the comments section by both competing EV brand owners (hi bro1999) and the Jim Chanos anti-Tesla Wolfpack trolls… and likely those two on some occasions overlap.

In the end… the more EV adoption and innovation by car makers the better… promotes vigorous competition… consumers ultimately win with better product at lower cost… and we get a more energy secure world.

CDAVIS

While on topic of Jim Chanos….

… scratch that…. kicking a guy that is bleeding-out lying (pun) face down in the gutter is not sporting. Perhaps better to hand him a dozen from Dunkin Donut.

Kind A Wierd

No one mentioned him, not in the comments, not in the article. You’re obsessed, truly. Chanos lives in your head, rent-free. It’s as if for you, anything that isn’t Tesla, but is EV, is somehow connected to some guy who shorts Tesla stocks. Do you think there’s a conspiracy? Do you think he’s going around to other car companies and paying them to build EVs to compete with Tesla? Tell the truth – you really think that don’t you?

Kind A Wierd

No, he doesn’t “have it backwards,” he’s got it going in exactly the right direction.

Things are going to get ugly around here in a year or so as the E-tron and Taycan come on line; who wants a minivan (the X) when they can have a Quattro? Who would take a eight-year-old design that looks like a worn bar of soap (the S) when they can have a Porsche? And of course, there will be even more options by 2020 from MB and others.

CDAVIS

@Kind A Wierd said: “No, he doesn’t “have it backwards,” he’s got it going in exactly the right direction…. who wants a minivan (the X) when they can have a Quattro? Who would take a eight-year-old design that looks like a worn bar of soap (the S) when they can have a Porsche?…”
————

@Kind A Wierd-

Lol… you call me out for having it wrong then proceed in your very next sentence to illustrate I’m right by bashing Tesla.

High comedy!

Please explain how a “worn bar of soap” outsold Mercedes S-Class, Porsche Panamera, and BMW 6/7 Series *combined* in the US?

How is it that Tesla is now selling more EVs in North America than all the other car makers combined?

Your sounding like Jim Chanos… delusional and fixated on bashing Tesla.

Mark.ca

You sure know how to read…

antrik

Nah, it’s not the “average” comment. It’s around 40% of comments. Another 40% is, “Tesla can’t do that, they are doomed!” The average evens out to something resembling white noise.

(The missing 20% are the rare actually meaningful comments…)

Djoni

You’r spot on!

Tech01x

The issue here is drivability. Plenty of cars have regen… higher levels of regen have issues with drivers and their ability to use it appropriately. Here, they are using professional drivers with prototypes and have adapted to such high regen in one pedal driving. It will be interesting to see if the general public would embrace one pedal driving with such high levels of regen.

The bigger issue is 248.5 miles of WLTP range. With a 95 kWh battery pack, that’s abysmal. Hopefully they can do better than that in the real version, because as it stands, that’s about 211 miles of EPA range. Assuming 90 kWh usable, that’s more than 425 Wh/mi, much worse than the I-Pace which is worse than a Model X.

Etain

I do not see how you can know what will be the EPA range since WLTP sometimes performs even better than EPA, not worse, but anyway, can you tell me what is the WLTP range of the 100kWh Model X?

I found some comments online saying that the Model X 100D range is 440km in the WLTP test, which would correspond to 418km with a 95kWh (like the e-tron) battery instead of a 100kWh one.

The e-tron has a WLTP range of more than 400km, so they are in fact very close (more than 400km for the e-tron with 95kWh battery, 440km for the Model X with a 100kWh battery, 418km for the Model X if it had a 95kWh battery).

The only question is if the Model X 100D range in WLTP is actually 440km, which I couldn’t confirm.

Jopp

Why should it be one pedal regen?

Shane Smith

Luckily the word is they made it highly customizable.

John

The cheating has already started before the car can be bought. Pikes peak for a car is almost like driving in a vacuum hyperloop tunnel. Try this at sea level in normal traffic, then give the numbers again please.

Kinfeboy

300Nm regen braking is 300Nm regen braking, be it at Pikes Peak or at sea level. You guys must have been ill when simple physics was on in 5th grade.

Marc

Indeed, air friction doesn’t slow down a car.

Kind A Wierd

They did – I’ve found that most of the commenters here are shockingly ignorant on just about topic they try to debate.

antrik

300 Nm? Where did you get that figure from?

Mark.ca

Going by tne numbers posted in the release, they seemed to have achieved the crazy regen level without sacrificing ev driving experience. If friction brakes come on only at over .3g than I assume the max regen level of deceleration is just below that which is not bad at all.

Mark.ca

Never mind, i’m taking it back! My eGolf takes about 15 seconds to go down from 60 mph in max regen and you can feel a pretty good deceleration. Anything close to .3g regen is crazy and impractical on day to day driving as it stops too fast. They did say that have different levels so it’s unlikely that a normal driver would get anywhere close to the stated max regen. It’s possible they come up with some new tech that enables them to recover more energy.

antrik

15 s 60-0 mph would average at about 0.18 g; but it’s probably less than that at 60 mph, and more than that at slower speeds. Might be 0.2 g max regen, which is a number I have often seen mentioned for other EVs. 0.3 doesn’t seem that much more; and I’ve also seen such a number mentioned for an existing EV at least once.

SJC

Not a lot of people drive Pike’s Peak.

Kind A Wierd

Not a lot of people would need to to benefit from this system.

You’re going to have to decouple your personalty from a corporation. Just because some other corporation other than Tesla does something well doesn’t mean you have to take it personally. There’s going to be a lot of competition coming on line soon, so if you don’t figure a way to remedy this disorder, you’re going to be really grumpy for pretty much the rest of your life, all over what a bunch of corporations are doing vis-a-vis the corporation you’ve chosen to meld your personality with.

CDAVIS

@Kind A Wierd said: “… Tesla … There’s going to be a lot of competition coming on line soon..”
———

Why your Tesla fixation?

@SJC did not even mention Tesla in his comment.

Shane Smith

I guess they shouldn’t have tied to the regen to GPS then…

How are so many of you this stupid?

John Hollenberg

My Tesla Model S85 regen does fine going downhill in the mountains. From Mt. Baldy Ski lift down to Claremont, CA I only need occasional, very light use of the brakes. The rest is all regen. I don’t need any more than I already have.

Kind A Wierd

Kids these days, am I right? So obsessed with always trying to making things “easier.” I remember when I had to walk to school uphill – both ways!

(⌐■_■) Trollnonymous

Doesn’t the Cadillac CT6 / ELR have all these features?

How is this new and “unprecedented”?

That 220kW regen, you can probably only get that going down Pikes Peak…………LMAO, anywhere else you’d most likely get at best 80-90kW for a few seconds.

Bill Howland

Must be a very heavy car for this thing to be something really new. My Bolt EV ‘recouperation’ also peaks at 0.3 g with the rod paddle and shifter in “L”. But it makes no where near as much energy, although the brakes are rarely used here either.

antrik

It’s heaver for sure; but that explains only part of the difference. The rest means it can achieve 0.3 g regen at higher speeds.

(Whether that’s useful in practice or not I don’t know.)

Pjwood1

Audi did great things, per Top Gear, with R8 Quattro’s ability to throttle-steer. Will etron be getting lift throttle over-steer, in other models, like Tesla 3P? 220kw, from the right axle balance, could really help point the car. #fun

Jason

I don’t know how this is unprecedented, maybe for Audi/VW group. The rest of the EV community has been using Regen for years. Just wish the Leaf used it consistently, the amount varies so much it is totally unpredicable.
220kW for about 3sec is about 0.18kwh. why don’t they just put in a Super Capacity or special battery that can take this load for the short amount of time it would be in operation? Sort of like a hybrid but now the hybrid part is special purpose batteries? You could then regen at any main battery SoC as this special battery would collect the high power, short duration regen and contribute it back to the system during acceleration.