Regenerative fuel heating apparatus and method for hypergolic combustion

Claim 1

In a reciprocating piston combustion chamber defined in part by a piston end face moving to compress air in said combustion chamber, air intake means for supplying air to said combustion chamber, fuel supply means, fuel injection means for directing fuel received from said fuel supply means into said combustion chamber, and exhaust system means for removing products of combustion from said combustion chamber, the improvement comprising heat exchanger means including a vessel disposed directly in said combustion chamber and receiving fuel from said fuel supply means immediately prior to injection, said vessel comprising an injector body having an internal cavity receiving fuel from said fuel supply means protruding into said combustion chamber towards said piston end face and formed with heat transfer fins, injector valve means within said injector body enabling controllable injection of fuel from said internal cavity; said piston formed with a cavity extending into said end face and located to receive said injector body as said piston moves to compress air in said combustion chamber, said cavity lined with insulation material thereby said fuel in said internal chamber is heated by direct contact of said injector body with the products of combustion in said combustion chamber, whereby said fuel in said internal cavity is regeneratively heated to a temperature on the order of 1000° F. to enable hypergolic combustion upon injection into compressed air in said combustion chamber.