Patent ID: 8113176
Filing Date: 2012-02-14
Classification: F02M

Abstract:
1. An injector for injecting fuel into combustion chambers of internal combustion engines, in particular a common-rail injector, comprising: a control valve having a valve piston which is adjustable in an axial direction by an actuator so that a fuel outflow conduit leading out of a control chamber to a low-pressure chamber is opened or blocked, and by opening and blocking the fuel outflow conduit, pressure in the control chamber, which is supplied with fuel via a pressure conduit, is varied, and as a result a nozzle needle operatively connected to the control chamber is adjustable between an open position which opens up a fuel flow and a closed position, wherein the valve piston has opposed face ends upon which low pressure prevails, the valve piston being disposed in a valve chamber communicating hydraulically with the control chamber, wherein a sleeve is provided in the valve chamber which surrounds the valve piston and guides the valve piston in the axial direction, wherein a spring having opposing ends is provided in the valve chamber between the sleeve and the valve piston, the spring being braced at one end on an end face of the sleeve and at the other end on the valve piston, wherein the spring presses the valve piston onto a valve seat and presses the sleeve onto a diametrically opposed bottom face of the valve chamber formed by a surface of a throttle plate, and wherein a diameter of the valve piston inside the sleeve is equivalent to the effective diameter of the valve piston at the valve seat.