[tocomment]

Actually what about putting in a bigger alternator and stronger belts and having it charge some super capacitors? That's already connected to the engine through a belt so whenever you use engine braking you could also be partially charging.

Can the alternator run in reverse though and provide energy to the engine/drive train?

[venomsnake]

Well it was just an idea conceived over 2-3 beers with a friend with just some basic napkin math that said we don't brake too much of the laws of physics. I can see multiple approaches working.

But the goal - make the existing fleet of vehicles better while cleaning the air as a bonus is a worthy one and smog is a first world problem.

Edit: honda have something similar

http://en.wikipedia.org/wiki/Integrated_Motor_Assist

[tocomment]

Wow, funny, that's actually how hybrids do work!

"Hybrid automobiles replace the separate alternator and starter motor with one or more combined motor/generator(s) (M/Gs) that start the internal combustion engine, provide some or all of the mechanical power to the wheels, and charge a large storage battery. When more than one M/G is present, as in the Hybrid Synergy Drive used in the Toyota Prius and others, one may operate as a generator and feed the other as a motor, providing an electromechanical path for some of the engine power to flow to the wheels. These motor/generators have considerably more powerful electronic devices for their control than the automotive alternator described above."

http://en.wikipedia.org/wiki/Alternator