Porsche approach to regenerative braking

[NormF]

https://cleantechnica.com/2023/01/27/porsches-approach-to-regenerative-braking/

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[tchavei]

https://cleantechnica.com/2023/01/27/porsches-approach-to-regenerative-braking/

This brings up a question I've been thinking about asking.

How does regenerative breaking work on a RWD?

I mean, usually the majority of breaking power is applied on the front wheels, right? Hence every car on the planet has bigger and more massive breaks in the front. Probably also the same reason why entry level cars have discs up front and drum in the back.

In a 4S, I'd assume most regenerative power would come from the front motor mimicking hydraulic brakes. On a RWD you don't have a front motor so how does it work? Do you feel the weight shifting from back to front as regenerative breaking is replaced by hydraulic breaking?

I'm curious. I tried searching the forum but came out empty handed.

 

[tigerbalm]

https://cleantechnica.com/2023/01/27/porsches-approach-to-regenerative-braking/

You'd think if the author was going to regurgitate an article from Porsche Engineering magazine, that they'd at least credit the original source.

Given there wasn't a single fact, quote or idea presented in this article that isn't in the original, this reads like plagiarism to me.

https://newsroom.porsche.com/en/202...ke-force-distribution-recuperation-30953.html

 

[WuffvonTrips]

This brings up a question I've been thinking about asking.

How does regenerative breaking work on a RWD?

I mean, usually the majority of breaking power is applied on the front wheels, right? Hence every car on the planet has bigger and more massive breaks in the front. Probably also the same reason why entry level cars have discs up front and drum in the back.

In a 4S, I'd assume most regenerative power would come from the front motor mimicking hydraulic brakes. On a RWD you don't have a front motor so how does it work? Do you feel the weight shifting from back to front as regenerative breaking is replaced by hydraulic breaking?

I'm curious. I tried searching the forum but came out empty handed.

That question was considered in this thread (posts #2&3)- I don't recall a conclusive answer being made subsequently.
https://www.taycanforum.com/forum/t...er-brake-system—thanks-to-recuperation.14515/

 

[f1eng]

This brings up a question I've been thinking about asking.

How does regenerative breaking work on a RWD?

I mean, usually the majority of breaking power is applied on the front wheels, right? Hence every car on the planet has bigger and more massive breaks in the front. Probably also the same reason why entry level cars have discs up front and drum in the back.

In a 4S, I'd assume most regenerative power would come from the front motor mimicking hydraulic brakes. On a RWD you don't have a front motor so how does it work? Do you feel the weight shifting from back to front as regenerative breaking is replaced by hydraulic breaking?

I'm curious. I tried searching the forum but came out empty handed.

Inevitably since maximum regeneration under braking is most efficient the RWD will have unconventional brake balance whilst braking up to the lower maximum regenerative brake torque it is capable of.
I am sure Porsche get the brake balance more towards optimum for on the limit and hard braking for the obvious reasons.

For me, AWD is not needed on most vehicles used on paved surfaces but it is a big gain on any surface for an EV entirely because of the better regenerative braking potential and balance. So I chose AWD for a road car for the first time in 50 years!

FWIW during the period AWD was legal in Formula 1 only 1 constructor thought it was worth trying and found it slower, maybe weight, maybe handling it was a bit before my time.
4WD was banned in the end to stop 6-wheeled cars which had a lot of potential but still may have been too heavy to compensate the gain.

Now F1 cars are hybrid all wheel drive would be a potential gain for regeneration and traction, but it is still against the rules.

 

[gusone]

RWD. I prefer coasting. I tried the recuperation for a journey and hated it. It felt heavy, drag like, less smooth and I couldn't judge the stopping point as well as I could coasting.

 

[tchavei]

RWD. I prefer coasting. I tried the recuperation for a journey and hated it. It felt heavy, drag like, less smooth and I couldn't judge the stopping point as well as I could coasting.

I understand but I was talking about regenerative braking. Not the regen button. Aka when you brake, "in theory", the car will be using the rear wheels to recuperate energy. This seems fine until you become "more sporty" and start braking later and later before a curve which on an RWD would mean a weight shift from back to forth whenever the actual brakes are used or not. I can't really imagine it.

Then again, when I was a kid, in germany, most if not all bicycles had pedal brakes on the rear wheels and we only rarely used the front hand brakes and I survived. Maybe the RWD Taycan is the same.

 

[f1eng]

I understand but I was talking about regenerative braking. Not the regen button. Aka when you brake, "in theory", the car will be using the rear wheels to recuperate energy. This seems fine until you become "more sporty" and start braking later and later before a curve which on an RWD would mean a weight shift from back to forth whenever the actual brakes are used or not. I can't really imagine it.

Then again, when I was a kid, in germany, most if not all bicycles had pedal brakes on the rear wheels and we only rarely used the front hand brakes and I survived. Maybe the RWD Taycan is the same.

Current Formula 1 cars are RWD and allow regenerative braking so there has to be a processor controlled balance between the torque applied during braking depending on how much regeneration can go on and how much is needed from the discs.
Brake balance is a key aspect of on the limit handling and dealing with mixing front disc, rear disc plus some regeneration was one of the most difficult things to sort out, back when it first started.

I am sur Porsche have the braking sorted but the RWD won’t be able to regenerate as much as the others at the limit, of course.

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