Fuel injector

Abstract

In a fuel injector, a plurality of pairs of first and second injection ports are formed in a distal end portion of a nozzle body, and are spaced from one another peripherally of the nozzle body. The angles of the first and second injection ports relative to an axis of the nozzle body is different from each other. The inner ends of the first injection ports are disposed at a valve seat, and the inner ends of the second injection ports are spaced from the inner ends of the first injection ports toward the distal end of the nozzle body in the axial direction of the nozzle body. Each pair of first and second injection ports have a substantially common outer end. At an initial stage of the lift of the needle valve, the injection of fuel from the first injection ports is effected preferentially due to a throttle effect between the abutment portion and the valve seat. When the amount of lift of the needle valve exceeds a specified lift amount, the injection of fuel from the second injection ports is effected preferentially. The speed of lift of the needle valve is limited by a lift speed limiting mechanism until the amount of lift of the needle valve reaches the specified lift amount, thereby prolonging the time period of the fuel injection from the first injection ports.