umm, while trying to sort out how semi-trucks do fuel injection, I saw this cummins ISX diagram, electrical power from exhaust is not a unicorn (but it is more complicated than that):
http://www.dieselpowermag.com/tech/g...e/viewall.html
they take heat, add fuel to make it hotter, run a turbine generator, ditch the mechanical accessories/alternator, and put some back with an electric motor.