Liquid i.e. fuel, injecting device, has electroactive material actuator triggering movement of head of needle, needle piston carried by end of needle, and hydraulic chamber connected to duct to maintain chamber supplied with liquid

摘要

The device (1) has a needle (12) with an end including a head (120) forming a valve on a seat (110) of a tubular body (11). An electroactive material actuator (10) e.g. magnetostrictive actuator, triggers movement of the head of the needle to open the valve. A hydraulic chamber (17) is defined by an actuator piston (101) and a needle piston (121). The needle piston is carried by the end of the needle. The hydraulic chamber is connected to a branch duct (19) for maintaining the hydraulic chamber supplied with liquid.