[Christ]

Hm... that's funny - the last time I thought about something like this, I was told it wouldn't work... I didn't believe the people that told me that, but I never tried it either... guess I should have.

Either way, it's not a complex design... take the scroll (exhaust side) of a turbo, mate it to a generator from an old VW bug, and drive it off the exhaust gasses. Obviously, we need to size the scroll wheel and housing so that we can scavenge enough energy from the exhaust to keep the generator moving at a decent clip constantly, and there needs to be a bypass system to allow the excess exhaust gasses to bypass the scroll housing while maintaining a given speed.