Patent ID: 7222608

Claim:
An injector for injecting high-pressure fuel comprising: a housing; a command piston supported by the housing to reciprocate therein; a control chamber enclosed by the housing and one end face of the command piston; a needle disposed at the other end face side of the command piston and slidably supported by the housing; a nozzle chamber enclosed by the housing and a leading end portion of the needle to accumulate the high-pressure fuel therein and provided with an injection hole for injecting the high-pressure fuel therethrough, the injection hole being opened and blocked by the leading end portion of the needle; a fuel inflow passage opening to the control chamber to supply the high-pressure fuel into the control chamber; a fuel discharge passage opening at a fuel discharge port to the control chamber to discharge the high-pressure fuel out of the control chamber, the fuel discharge port being as close to an uppermost position of the command piston, at which the command piston minimizes a volume of the control chamber, as possible without the fuel discharge port being blocked by the command piston in said uppermost position; and an electric valve for opening and blocking the fuel discharge passage.