2014 M3 to have 3 turbos?

[Howard]

I don't see how regen braking could ever provide the high power needed to provide any boost. IIRC, you need a lot of power to get even 1psi of boost.

If you brake as fast as you accelerate you can get back upwards of 100-200kW.

 

[yhelothar]

I'm guessing the benefit of an electric supercharger is that it could use regenerative braking to increase efficiency in the system?
Otherwise it seems that an electric supercharger can't be any more efficient than a standard mechanical one. Otherwise it'd be turning mechanical energy into electric energy and back to mechanical. I'm no German engineer, but that seems less efficient.

 

[Dman8777]

E = 1/2 mv^2
m = 1400 kg
v = 100 kmh
E = ~540 kW

Obviously regenerative braking doesn't recover 100% of that but you can do a lot with 500 kW.

 

[yhelothar]

E = 1/2 mv^2
m = 1400 kg
v = 100 kmh
E = ~540 kW

Obviously regenerative braking doesn't recover 100% of that but you can do a lot with 500 kW.

like accelerate a 1400kg car to ~100kmh?

 

[DivideBYZero]

BMW has never used a sequential setup AFAIK.

I think after 4 cylinders per turbo, it's a case of diminishing returns in terms of complexity/performance gain.

hehe

BMW's 204hp four cylinder diesel is a sequential twin turbo setup.

 

[Howard]

E = 1/2 mv^2
m = 1400 kg
v = 100 kmh
E = ~540 kJ

fixed

 

[LTC8K6]

If you brake as fast as you accelerate you can get back upwards of 100-200kW.

"Using" doesn't equal "getting back"...

 

[Howard]

"Using" doesn't equal "getting back"...

I don't understand the thrust of your statement.

 

[LTC8K6]

Who is getting back 100-200kw in regen braking? A locomotive?

Who doesn't always brake much faster than they accelerate?

 

[Howard]

Who is getting back 100-200kw in regen braking? A locomotive?

Who doesn't always brake much faster than they accelerate?

200kW = 268HP

Uh, I suppose you could always do a panic stop, but I don't usually brake that fast. And how is this relevant?

 

[Jeff7181]

um, if it's electric it's not a turbo. it's an electrosupercharger.

+1

Turbochargers are exhaust driven. If it's not exhaust driven, it's not a turbocharger.

 

[KentState]

In the end, I would love to see how a very complex M3 engine compares to something like an LS3 with respects to efficiency, torque curve and over size and weight. Seems very German to engineer something so complex just to prove they can do it.

 

[disappoint]

I'm guessing the benefit of an electric supercharger is that it could use regenerative braking to increase efficiency in the system?
Otherwise it seems that an electric supercharger can't be any more efficient than a standard mechanical one. Otherwise it'd be turning mechanical energy into electric energy and back to mechanical. I'm no German engineer, but that seems less efficient.

You know hybrid electric is more efficient than internal combustion alone right? And that is turning mechanical energy into electrical and back to mechanical again right?

 

[LTC8K6]

200kW = 268HP

Uh, I suppose you could always do a panic stop, but I don't usually brake that fast. And how is this relevant?

Well, the entire battery capacity of the Tesla roadster is 53Kwh. So how much are they getting back in regen braking?

In my earlier comment I should have said who "can't" always stop much quicker than they accelerate. Pretty much all cars can stop much quicker than they can accelerate, depending on conditions.

Regen braking has to be limited to the traction available. You can't regen brake any harder than you could normally brake for the conditions.

Even if your regen braking system could recoup 200kw on paper, you might not be able to get anywhere near that in the real world.

 

[Howard]

Well, the entire battery capacity of the Tesla roadster is 53Kwh. So how much are they getting back in regen braking?

In my earlier comment I should have said who "can't" always stop much quicker than they accelerate. Pretty much all cars can stop much quicker than they can accelerate, depending on conditions.

Regen braking has to be limited to the traction available. You can't regen brake any harder than you could normally brake for the conditions.

Even if your regen braking system could recoup 200kw on paper, you might not be able to get anywhere near that in the real world.

Yes, peak braking power almost always exceeds peak engine power. Similarly, a regenerative system will most likely not be powerful enough to do all the braking on its own. Doesn't mean we shouldn't have them, and it certainly doesn't mean the status quo will not change in the future.

Anyway, even if the regen system isn't all that powerful, it doesn't affect whether a car should have an ES charger or not.

EDIT: BTW, 53 kWh is 53 kW... for an hour. Meaning with 100% efficiency, you would need to be braking for an HOUR at ~70HP (which is not exactly super slow braking) worth to fully charge the battery.

 

[LTC8K6]

Well, we know that any form of manifold boost requires a lot of power for even modest boost pressures. So where is that power coming from if it's going to be electric?

It seems likely to me that it must be an intermittent system using some form of storage of a built up charge. That is, it would only be available for short periods at intervals that allow enough time for a recharge.

That may work out very well if the technology has advanced enough.

 

[Howard]

Well, we know that any form of manifold boost requires a lot of power for even modest boost pressures. So where is that power coming from if it's going to be electric?

It seems likely to me that it must be an intermittent system using some form of storage of a built up charge. That is, it would only be available for short periods at intervals that allow enough time for a recharge.

That may work out very well if the technology has advanced enough.

I assume that this tri-charger system uses the ES charger only during low RPM. The other two chargers are probably turbos.

So, it may be that the limited duty cycle of the ES charger doesn't require a significant amount of electrical energy and power.

EDIT: Article explicitly says only one of them is ES.

 

[yhelothar]

You know hybrid electric is more efficient than internal combustion alone right? And that is turning mechanical energy into electrical and back to mechanical again right?

Yeah but hybrid electric uses regenerative braking to accomplish that. :hmm:
It also allows for the engine to turn off when idling.

 

[exdeath]

Well, we know that any form of manifold boost requires a lot of power for even modest boost pressures. So where is that power coming from if it's going to be electric?

It seems likely to me that it must be an intermittent system using some form of storage of a built up charge. That is, it would only be available for short periods at intervals that allow enough time for a recharge.

That may work out very well if the technology has advanced enough.

Lol I can see it now:

"first run, he gets me by half a car. second and third run, I get him by 3 cars."