Fuel systems for internal combustion engines

Claim 1

A fuel system for an internal combustion engine comprising mixing means for forming a mixture of fuel and air, conduit means for directly delivering mixed fuel and air from a mixing means to a combustion site of said engine, a heat exchanger disposed about said conduit means, means for delivering a heating medium to said heat exchanger, said medium being heated by engine operation and means operatively associated with said conduit means causing the said mixed fuel and air to be diverted from said conduit means and to pass through said heat exchanger, said means operatively associated with said conduit means comprising inlet port means opening from said conduit to said heat exchanger, return port means disposed down stream of said inlet port means and opening from said heat exchanger to said conduit means and valve means disposed in said conduit means between said inlet and return port means, said valve means being movable between closed position in which fuel air mixture is caused to pass through said heat exchanger and an open position in which fuel air mixture is passed directly to said combustion site, said heat exchanger comprising an inlet header for heating medium, a return header for that medium, and a plurality of heat exchanging tubes extending between said headers and within a heat exchange chamber, said headers and said chamber being of annular form and wherein said conduit means for delivering mixed fuel and air from a mixing means to the combustion site includes a conduit section extending axially through said headers and said chamber.