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Originally Posted by NISFAN
But now you are in the realms of adding AC/DC invertors, separate battery packs, etc. And for what benefit?
In a racing car, easy, as the power demand can be mapped for an individual circuit.
On a road going car, how do you predict a WOT event with enough time to drive an anti lag system that will be driven with much less energy than the normal energy fed into the system in the first place? It just makes no sense whatsoever.
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The LaFerrari, Mclaren P1 and Porsche 918 all use hybrid technology to add power. How far BMW has taken the hybrid tech on the next gen M3/M4 will be interesting to see.
And a hybrid/electric turbo can accelerate from
40,000 to 120,000 rpm in less than 450 ms. This rate of acceleration eliminates the turbo lag which is a major limiting factor on the performance of standard turbocharged engines.
http://en.wikipedia.org/wiki/Hybrid_turbocharger
The electric motor (MGU) reacts so much faster than the turbine would from exhaust gases, this is where you can loose most of the turbo lag. And as I mentioned earlier you could even have a "M-mode" where the MGU actually keeps the turbo spinning at a rpm where boost constantly is made during deceleration, part throttle and where the turbo would "be boosting" even before WOT. And while at WOT the MGU acts as a generator/boost controller, recuperating energy and controlling boost levels at the same time
From an article on BMW's electric turbo patents:
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The turbine and compressor spin on separate axles that can be uncoupled by a clutch — with the electric motor constantly running in the middle. During full-throttle starts, the electric motor runs the compressor in an instant-on fashion, virtually eliminating the time it would normally take the exhaust gases to spin up a traditional turbine. When the turbine's up to speed, the clutch engages the turbine shaft to run in conjunction with the electric motor. Naturally, all of this switchery happens at ridiculously high RPMs.
Now here's the cool part. Rather than using a wastegate to hold back the speed of the turbine, the electric motor-generator kicks into generate mode. The resulting electrical current flows back to the battery (or, potentially, to a supercapacitor), while the additional load from the generator regulates turbine speed.
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http://jalopnik.com/5855317/will-bmw...-end-turbo-lag
Borg Warners eBooster:
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The eBooster permits the development of small and efficient high-performance turbocharged engines whose dynamic response matches that of large non-supercharged engines of the same output class. The superiority of the eBooster was impressively demonstrated in close cooperation with various customers for gasoline engines as well as for diesel engines.
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http://www.3k-warner.de/products/eBooster.aspx
Bowman electric turbos for trucks:
http://www.bowmanpower.com/technolog...turbochargers/
Turbos with a electric generator/motor unit makes a lot of sense to me