HYDROGEN-DIESEL DIRECT INJECTION DUAL-FUEL SYSTEM FOR INTERNAL COMBUSTION ENGINES

A hydrogen-diesel direct injection dual-fuel system for an internal combustion engine enables retrofitting to existing diesel engines. The system comprises: a cylinder head of the engine having a first and a second injector hole; a diesel pilot injector positioned in the first injector hole; and a hydrogen injector positioned in the second injector hole; wherein the hydrogen injector comprises: a gasoline direct injector having an external shank and a distal output end; and a nozzle cap covering the distal output end, wherein the nozzle cap is welded to the external shank.