Fuel pump and direct fuel injection engine

The invention relates to a fuel pump, of which sliding mechanism parts in its fuel chamber have good wear resistance under a severe environment, and to a direct fuel injection engine using the fuel pump. [0002] In a fuel pump for pressurizing and delivering fuel to a fuel injector of a vehicle engine, at least one of sliding surfaces of a slant plate (9), a slipper (10) and a plunger (11) sliding in a lubricating oil and at least one of sliding surfaces of sliding members of a plunger (11) and a cylinder (13) contacting with and sliding on each other through the fuel are formed of a hardened layer composed of any one of a nitrided layer, a carburization-quenched layer and a carbonitrided layer, or coated with a high corrosion resistant and hard metal compound layer over the hardened layer.