Electrically assited turbo


http://popularmechanics.com/automoti...d/index3.phtml

 

hmmm.... interesting

 

Interesting, my only concern would be the longevity with the high heat, but i'm sure they are aware of that, afterall.

 

If you read the article, they state that these are to assist the boost at low end when the exhaust pressure isn't enough to spin the turbo to boost levels - in other words, these are for engines so small that they can't get out of their own way...

 

put it on an Elise

 

But they do have the effect that it can give an electrical charge when its not working to put boost on the engine, but then again isnt that what an alternators for.

 

or if the turbos are so big that even a big block cant even have it spooled til 3000 rpm

 

I'm thinking some of the people on the forum who wanted to run a big single turbo do to space.

 

Seems to me that at any real pressure, the electric motor only acts as a hinderance in the ability of the turbine to spin as free as it could. Now if that motor also becomes a generator and has to develop current, it just adds that much more drag to the system.

Still, the concept is intriging.

 

It has more to do with the size of the turbocharger compared to the size of the engine. Use a big enough turbo (there are even turbos made for big sea ships), and it'll experience some lag. I also have a little VATN turbo from aerodyne on my 2.0 liter Focus hatchback, and it spools very quickly (then again that turbo in a smaller trim is used on motorcycle applications).

Centrifugal superchargers are the only ones boasting compressor efficiencies that rival turbos. The big advantage, IMO, of a turbo vs a centrifugal supercharger is having the compressor RPM independent of engine RPM (not just the "free ride" from the exhaust energy). With an electronic boost controller, you can set the rpm and respective boost you'd like to have at any RPM with the exception of low RPMs and lag. While the turbos are constantly improving in lowering the mass, efficiency, and reducing friction with ceramic bearings, low RPMs are still somewhat of an issue if you are looking for lots of boost from a big ol' turbo. An electric motor that can give it that quick initial RPMs then totally eliminates one of the few last disadvantages of a turbo setup. The drag from the electric motor used as a generator is still going to be minimal considering that you have a compressor wheel that can now pretty much ALWAYS be in its efficiency island for the coolest charge possible and you are still mainly using wasted exhaust energy with only slight backpressure increase (can be compensated for with more free flowing mufflers since a turbo muffles the exhaust by itself... Dodge's SRT-4 has no mufflers for example).

At that point, cost and exhaust routing concerns with a V-engine are the only downsides I could think of of this kind of turbo vs any supercharger design. A huge electrically assisted VATN turbocharger using aircooled ceramic bearings and an electronic controller would be sweet if it could be made reliable!