US Patent 7654475 Fuel injection valve

A fuel injection valve has a first groove cut in a peripheral surface of a needle valve and second grooves cut in a seat surface of a nozzle tip. The first groove is provided so that the needle valve is rotated by flow of the fuel in the first groove caused by a reciprocating motion of the needle valve, and upper and lower ends of the first groove are opened to the outside so that the fuel can be introduced into the groove. The second grooves are twisted or tilted in the same direction as the rotating direction of the needle valve and are cut along the circumferential direction of the nozzle tip. The second grooves have an edge part for scraping off solid matters into the second grooves in cooperation with the tip seat surface of the needle valve by the rotation of the needle valve.