Here's a little bit about Audi's implementation: http://www.worldcarfans.com/112092048467/audi-electric-bi-turbo-engine-revealed http://www.worldcarfans.com/112

Here's a little bit about Audi's implementation: http://www.worldcarfans.com/112092048467/audi-electric-bi-turbo-engine-revealed http://www.worldcarfans.com/112092048467/audi-electric-bi-tu... It basically uses the high voltage electric supercharger to provide initial boost while the turbocharger is still spooling up.