A large portion of the engergy in the fuel of an internal combustion engine gets dumped out the tailpipe in the form of heat energy. Another large portion, particularly in part throttle conditions, is consumed in overcoming pumping losses.

My idea: use some type of large capacity heat exchanger to use exhaust (and/or cooling system) heat to significantly pre-heat the engine's intake air during part throttle operation.

A hotter intake charge would occupy much greater volume for a given mass of air. Since more volume is needed in order to get the same mass, a much larger throttle opening will be required (compared to the same engine without this system), resulting in much less maifold vacuum and therefore reduced pumping losses.

Additionally, the higher air temperature will ensure that the fuel is completely vaporized before it ever reaches the combustion chamber.

A bypass valve would allow cool air into the intake whenever more power is needed for acceleration.


... so how does that sound?