RE: BMW M8 confirmed with new adjustable brake tech

RE: BMW M8 confirmed with new adjustable brake tech

Thursday 9th May

BMW M8 confirmed with adjustable brake tech

M division develops a vacuum-free system that offers more feel; plus new Track drive mode for 600hp two-door



BMW has confirmed that its upcoming M8 super-coupe and convertible models will use all-new adjustable brake technology that will offer more feel. The introduction of a vacuum-free brake booster that uses an electronic actuator is said to drastically boost left pedal response, while also allowing two braking modes to be created for the first time.

Comfort mode reduces the amount of pressure required from the driver to slow the car, while Sport increases the required input to unlock more feedback through the pedal, as you might expect. The new hardware, which also saves two kilograms over alternatives, is said to offer unimpeded feel even under heavy braking on wet surfaces and during high lateral loads because it can constantly adjust its parameters.

More interestingly, BMW claims that the actuator-tech can counter any loss of feedback provided by hot brakes, which begs the question of whether it will also mask the sort of information passed through a pedal that warns of impending overheating. Surely BMW’s M division boffins will have an answer for that – but rest assured it’s something we’ll be investigating once the M8 is revealed this September.


Also new for the 4.4-litre V8-powered M8 models will be a Track mode, accessible when the M button is pressed and held for a few seconds. Do this and the 600hp two-door will turn off all of its comfort and driver assist features, the radio will turn off and the infotainment system will display track-specific data. Alternatively, click the M button quickly and the car will be switched to Sport mode, adjusting the damping, steering and powertrain responses as per usual.

Along with the part-time rear-wheel drive capabilities of the M8’s xDrive hardware, it all points to a super-coupe that’s being honed to offer some pretty serious track performance. This is understandable, of course, what with the M8 ranking as BMW’s performance halo – and suggests we’ll have quite the test on our hands when the car reaches roads before the close of 2019. There’ll be more after that, of course, with a 625hp Competition variant due and a four-door Gran Coupe to follow in 2020.






Author
Discussion

mrclav

Original Poster:

791 posts

164 months

Thursday 9th May
quotequote all
Interesting. Has this tech been used on anything before (to my knowledge no)? Maybe someone more learned can chime in...?

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
Clever bit of marketing this. They're using the Bosch IPB (Integrated Power Brake) like most of the industry in the coming years which replaces the ABS, Brake Booster and Master Cylinder with a 'one box' solution. Main drivers are a focus on efficiency and switch to hybridisation (the IPB allows easy integration of regen braking) and the addition of Level 2+ ADAS features that need full brake control.

BMWs involvement in this will extend along the lines of deciding the brake pedal map (the pedal isn't directly connected to anything other than a pedal feel simulator during normal braking) and the stability control calibration. You get the ability to add selectable maps for free effectively as it's 'just' a pedal travel/force curve.

Alfa already have the Continental equivalent on the Gulia and Stelvio, and the majority of the other OEMs will be using this or similar in the coming Model Year.

https://www.bosch-mobility-solutions.com/en/produc...

An interesting by-product of the tech is the removal of feedback through the pedal. So you get no vibration during ABS activation, and, as mentioned, no sense that the brakes are fading. Whether you see this as good or bad is entirely personal. For me....I quite like the feedback that you're close to the limit of braking when the ABS starts to control the wheels (although having driven quite a bit with an IPB recently, you can still sense its activation through the steering and the noise of the brake modulation) but the idea that you have no idea when there's fade is a little un-nerving. First thing you'd know about it would be the car failing to stop. I assume BMW have implemented some warning or powertrain de-rate to counter this though.

Edited by RacerMike on Thursday 9th May 12:58

belleair302

6,055 posts

148 months

Thursday 9th May
quotequote all
How heavy will this car be. The current one isn't light.

scarble

5,194 posts

98 months

Thursday 9th May
quotequote all
Not sure if anyone has it on the market yet, but sure a few are planning to in the near future though, it's probably the Bosch system:
https://www.bosch-mobility-solutions.com/en/produc...

I wonder if has that delightfully artificial delayed weight feeling of early epas systems.

eta: ok Mike beat me to it, both on time and level of detail frown
But! I think the Bosch system actually connects directly to the back of the pedal and the big assistance motor sits directly on the other side of the firewall with a short linkage.

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
scarble said:
Not sure if anyone has it on the market yet, but sure a few are planning to in the near future though, it's probably the Bosch system:
https://www.bosch-mobility-solutions.com/en/produc...

I wonder if has that delightfully artificial delayed weight feeling of early epas systems.
iBooster is actually now 'old' tech! You're not totally disconnected from the brakes with that.

Tesla Model S/X/3, Porsche 918 and the Jaguar I Pace all use it, along with quite a few others.
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scarble

5,194 posts

98 months

Thursday 9th May
quotequote all
Ah ok, not sure how a completely removed system is any better than iBooster, as that can still vary pedal feel. Unless it's a weight/cost thing.
Is braking your area?

Doobs too

99 posts

186 months

Thursday 9th May
quotequote all
Prius uses the same technology (Electronic Brake Booster) to deliver series regen braking. I dare say other hybrids and EV's will do the same.

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
scarble said:
Ah ok, not sure how a completely removed system is any better than iBooster, as that can still vary pedal feel. Unless it's a weight/cost thing.
Is braking your area?
Stability Control and Hybrid Braking amongst other stuff along with the bits that affect vehicle dynamics.

iBooster works by disconnecting you from the brakes by closing solenoids. You still push fluid, but it gets pushed back into the reservoir. When pressure is required though (i.e. when the regen braking limit is reached) it has to allow fluid into the system, so opens the solenoids. It counters any change in pedal stroke by automatically moving the plunger in the master cylinder, but you get some feedback through the pedal, and it's hard to be totally transparent in the way it does this, so getting consistent brake feel is hard.

IPB is totally disconnected. Pressing the pedal literally just moves a spring and a potentiometer. It's then up to the system to decide how to deliver that braking force (through regen or hydraulic pressure), and nothing has to happen with the pedal. It actually feels a lot more natural than an iBooster weirdly, but then the majority of 'pedal feel' during braking is just your brain interpreting the amount of decel you get with the amount of travel/resistance in the brake pedal. You obviously don't get true pedal feel though, but arguably only a non boosted system will do this anyway, so 99% of cars on the road are preeminently not feeding back anything about the calipers to the driver.

midenginedcoupe

4,218 posts

73 months

Thursday 9th May
quotequote all
I thought brake by wire had been done ages ago?

https://en.wikipedia.org/wiki/Sensotronic_Brake_Co...

Feeling (and hearing) the reservoir vibrate the brake pedal periodically never stops being a little weird.

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
midenginedcoupe said:
I thought brake by wire had been done ages ago?

https://en.wikipedia.org/wiki/Sensotronic_Brake_Co...

Feeling (and hearing) the reservoir vibrate the brake pedal periodically never stops being a little weird.
Indeed it was. And the limits of technology meant it wasn't very popular/got shelved until it became needed for other reasons/technology caught up.

midenginedcoupe

4,218 posts

73 months

Thursday 9th May
quotequote all
RacerMike said:
midenginedcoupe said:
I thought brake by wire had been done ages ago?

https://en.wikipedia.org/wiki/Sensotronic_Brake_Co...

Feeling (and hearing) the reservoir vibrate the brake pedal periodically never stops being a little weird.
Indeed it was. And the limits of technology meant it wasn't very popular/got shelved until it became needed for other reasons/technology caught up.
the article said:
... while also allowing two braking modes to be created for the first time.
I'd be amazed if SBC didn't allow this. That sounds like a strong claim.

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
midenginedcoupe said:
RacerMike said:
midenginedcoupe said:
I thought brake by wire had been done ages ago?

https://en.wikipedia.org/wiki/Sensotronic_Brake_Co...

Feeling (and hearing) the reservoir vibrate the brake pedal periodically never stops being a little weird.
Indeed it was. And the limits of technology meant it wasn't very popular/got shelved until it became needed for other reasons/technology caught up.
the article said:
... while also allowing two braking modes to be created for the first time.
I'd be amazed if SBC didn't allow this. That sounds like a strong claim.
I'm not too familiar with how SBC delivered its pedal feel, but yes....the possibility to change brake feel depending on mode has been around for ages. I think at one point we considered it, but decided against it/it wasn't strictly my domain to make that decision.

foxhounduk

204 posts

121 months

Thursday 9th May
quotequote all
I MIGHT BE MISSING SOMETHING BUT CARS ALREADY HAD A "GOOD" BREAK-FEEL IN THE PAST- GO BACK 20 YEARS. I LOVE HOW THEY KEEP ADDING GUBBINS WITH MORE SENSORS AND ACTUATORS TO MAKE IT FEEL LIKE HOW A GOOD BREAK PEDAL USED TO FEEL,WHEN EVERYTHING WAS MUCH SIMPLER.

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
foxhounduk said:
I MIGHT BE MISSING SOMETHING BUT CARS ALREADY HAD A "GOOD" BREAK-FEEL IN THE PAST- GO BACK 20 YEARS. I LOVE HOW THEY KEEP ADDING GUBBINS WITH MORE SENSORS AND ACTUATORS TO MAKE IT FEEL LIKE HOW A GOOD BREAK PEDAL USED TO FEEL,WHEN EVERYTHING WAS MUCH SIMPLER.
Wow! laugh

PH Gold Right there....

BlackLabel

11,789 posts

64 months

Thursday 9th May
quotequote all
Shame they’re not putting the v12 from the m760 into the M8.

Krikkit

15,064 posts

122 months

Thursday 9th May
quotequote all
RacerMike said:
foxhounduk said:
I MIGHT BE MISSING SOMETHING BUT CARS ALREADY HAD A "GOOD" BREAK-FEEL IN THE PAST- GO BACK 20 YEARS. I LOVE HOW THEY KEEP ADDING GUBBINS WITH MORE SENSORS AND ACTUATORS TO MAKE IT FEEL LIKE HOW A GOOD BREAK PEDAL USED TO FEEL,WHEN EVERYTHING WAS MUCH SIMPLER.
Wow! laugh

PH Gold Right there....
Surprised it took so many posts, but that is rather magnificent.

RacerMike said:
Clever bit of marketing this. They're using the Bosch IPB (Integrated Power Brake) like most of the industry in the coming years which replaces the ABS, Brake Booster and Master Cylinder with a 'one box' solution. Main drivers are a focus on efficiency and switch to hybridisation (the IPB allows easy integration of regen braking) and the addition of Level 2+ ADAS features that need full brake control.

BMWs involvement in this will extend along the lines of deciding the brake pedal map (the pedal isn't directly connected to anything other than a pedal feel simulator during normal braking) and the stability control calibration. You get the ability to add selectable maps for free effectively as it's 'just' a pedal travel/force curve.

Alfa already have the Continental equivalent on the Gulia and Stelvio, and the majority of the other OEMs will be using this or similar in the coming Model Year.

https://www.bosch-mobility-solutions.com/en/produc...

An interesting by-product of the tech is the removal of feedback through the pedal. So you get no vibration during ABS activation, and, as mentioned, no sense that the brakes are fading. Whether you see this as good or bad is entirely personal. For me....I quite like the feedback that you're close to the limit of braking when the ABS starts to control the wheels (although having driven quite a bit with an IPB recently, you can still sense its activation through the steering and the noise of the brake modulation) but the idea that you have no idea when there's fade is a little un-nerving. First thing you'd know about it would be the car failing to stop. I assume BMW have implemented some warning or powertrain de-rate to counter this though.
Great post, I assumed they were using something from Bosch, and now it's confirmed. Does anyone build their own ABS systems these days?


RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
Krikkit said:
Great post, I assumed they were using something from Bosch, and now it's confirmed. Does anyone build their own ABS systems these days?
Basically no. Although a subsidiary of Toyota (Advics) make theirs I believe. The majority of European and US vehicles use Bosch, Continental (Ate) or TRW, and then China/Japan use Mobis, Nissin, Hitachi and Mando too. Big movers at the moment are Mando. They're being quite aggressive on pricing and have actually demo;d some pretty interesting tech.

Overall it's a really aggressive market. There's big volumes involved, it's a tough system to develop, and there's going to be increasing focus on what the suppliers can deliver for BEVs and Self Driving features.

Krikkit

15,064 posts

122 months

Thursday 9th May
quotequote all
RacerMike said:
Krikkit said:
Great post, I assumed they were using something from Bosch, and now it's confirmed. Does anyone build their own ABS systems these days?
Basically no. Although a subsidiary of Toyota (Advics) make theirs I believe. The majority of European and US vehicles use Bosch, Continental (Ate) or TRW, and then China/Japan use Mobis, Nissin, Hitachi and Mando too. Big movers at the moment are Mando. They're being quite aggressive on pricing and have actually demo;d some pretty interesting tech.

Overall it's a really aggressive market. There's big volumes involved, it's a tough system to develop, and there's going to be increasing focus on what the suppliers can deliver for BEVs and Self Driving features.
I had no idea there were so many suppliers, how interesting!

Is brake engineering your bread and butter?

RacerMike

2,265 posts

152 months

Thursday 9th May
quotequote all
Krikkit said:
I had no idea there were so many suppliers, how interesting!

Is brake engineering your bread and butter?
I wouldn't say I'm a brakes engineer. Brakes engineering in the traditional sense is brake sizing, pad performance and classic hydraulics. My bread and butter is stability control/ABS/Traction Control and active dynamics system calibration, but that means understanding the hardware too.

KPdiEwcar

3 posts

Thursday 9th May
quotequote all
midenginedcoupe said:
RacerMike said:
midenginedcoupe said:
I thought brake by wire had been done ages ago?

https://en.wikipedia.org/wiki/Sensotronic_Brake_Co...

Feeling (and hearing) the reservoir vibrate the brake pedal periodically never stops being a little weird.
Indeed it was. And the limits of technology meant it wasn't very popular/got shelved until it became needed for other reasons/technology caught up.
the article said:
... while also allowing two braking modes to be created for the first time.
I'd be amazed if SBC didn't allow this. That sounds like a strong claim.
It may depend on how you define multiple braking modes. The owners' manuals of the time did state "If you activate the SBC brake system with the brake pedal..." = so the brake pedal was one activiation method... You could also activate the system by opening the doors. Does that count as multiple braking modes ?


SBC would 'anticipate' different conditions and be prepared for them, or take control (the first gen of SBC would basically anticipate the need for braking before you even touched the pedal). But there weren't driver selectable braking modes.