Patent ID: 7383817

Claim:
An injector comprising: a boosting mechanism that boosts fuel; and a nozzle that injects and supplies the fuel boosted by the boosting mechanism, wherein: the boosting mechanism includes: a tubular piston that has a bore, which extends through the tubular piston in a direction of a longitudinal axis of the tubular piston; and a column piston having a first portion that is loosely received by the tubular piston to define a clearance and having a second portion, which projects from the tubular piston, and which engages with the tubular piston, the first portion having a diameter smaller than a diameter of the second portion; the tubular piston is slidably received by a first cylinder; and the second portion of the column piston is slidably received by a second cylinder, which is provided generally coaxially to the first cylinder, and which has a diameter different from that of the first cylinder, the second cylinder and an end portion of the second portion opposite the tubular piston defining a boosted chamber.