COOLING STRUCTURE FOR FUEL INJECTION VALVE

The present invention provides a cooling structure of a fuel injection valve that can cope with the high load operation of the engine by efficiently transferring heat from a nozzle to a cylinder head, thereby improving the cooling efficiency of the injection valve including the nozzle valve. In the cooling structure, fuel is injected through an injection hole by opening and closing of the needle valve 2 that is reciprocatably fit inside the nozzle and removably attached to a seating portion of the nozzle at a tip. The cooling structure comprises a metal ring member 10 which is interposed between an outer circumferential face of the nozzle nut 3 and an inner circumferential face of the outer sleeve 6 so as to transfer heat from the nozzle 1 to the cylinder head 110 via the nozzle nut 3 and the outer sleeve 6.