Patent attributes
A fuel injector comprising a valve member which is engageable with a valve seating to control fuel delivery from the injector, an actuator arrangement and an amplifier arrangement for transmitting movement of the actuator arrangement to the valve member. The amplifier arrangement comprises a piston member with which the actuator arrangement is cooperable to apply a retracting force to the piston member, and a control chamber for fluid. The amplifier arrangement preferably comprises a mechanical coupling arrangement for coupling movement of the piston member to the valve member upon application of an initial retracting force to the piston member. The amplifier arrangement is arranged such that, upon application of the initial retracting force, the valve member is caused to move with the piston member away from the valve seating, movement of the valve member being decoupled from the piston member following initial movement of the valve member away from the valve seating so as to provide variable amplification of movement of the actuator arrangement to the valve member.
