Patent ID: 7891585

Claim:
A fuel injection valve comprising a valve body ( 10 ) that can be seated on a valve seat ( 2 ) connected to an inner end of a fuel injection hole ( 3 ), a return spring ( 31 ) that urges the valve body ( 10 ) in the seating direction, an electromagnetic actuator (A 1 ) that, by passing current therethrough, moves the valve body ( 10 ) in an inwardly-opening direction, and a magnetostrictive actuator (A 2 ) that, by passing current therethrough, elongates a movable part assembly ( 43 ) extending from the valve body ( 10 ) to a movable core ( 24 ) of the electromagnetic actuator (A 1 ), wherein the magnetostrictive actuator (A 2 ) is formed from a solid magnetostrictive element ( 15 ) provided between the valve body ( 10 ) and the movable core ( 24 ) of the electromagnetic actuator (A 1 ) so as to couple the valve body ( 10 ) and the movable core ( 24 ), a preload spring ( 13 ) provided between the valve body ( 10 ) and the movable core ( 24 ) so as to apply a compressive preload in the axial direction of the valve body ( 10 ) to the magnetostrictive element ( 15 ), and a second coil ( 42 ) mounted on a valve housing (H) housing the valve body ( 10 ), the movable core ( 24 ), the magnetostrictive element ( 15 ), and the preload spring ( 13 ) and forming between these and the valve housing (H) a fuel flow path communicating with the fuel injection hole ( 3 ), the second coil ( 42 ) elongating the magnetostrictive element ( 15 ) against the preload by the passage of current.