Patent ID: 6644281
Filing Date: 2003-11-11
Classification: F02M

Abstract:
A fuel injection apparatus for an internal combustion engine, the apparatus comprisinga high-pressure fuel pump (10), a fuel injection valve (12) connected to the fuel pump for each cylinder of the engine, the high-pressure fuel pump(10) having a pump piston (18)driven by the engine into a stroke motion, which piston defines a pump working chamber (22) which is supplied with fuel from a fuel tank (24), each fuel injection valve (12) having a pressure chamber (40) connected to the pump working chamber (22) and an injection valve member (28) which controls at least one injection opening (32) and on which the pressure prevailing in the pressure chamber (40) acts in an opening direction (29) against a pressure surface (42) embodied on the injection valve member (28), the injection valve member (28) being movable counter to a closing force, in an opening direction (29) in order to unblock the at least one injection opening (32), a first control valve (68) that controls a connection (66) between the pump working chamber (22) and a relief chamber (24), a second control valve (70) that controls a connection (64) between a control pressure chamber (52) of the fuel injection valve and a relief chamber (24), the pressure prevailing in the control pressure chamber (52) at least indirectly acting on the injection valve member (28) in a closing direction and the control pressure chamber (52) being connected to the pump working chamber (22), and a control piston (50) in the control pressure chamber (52), which piston acts on the injection valve member (28) and which has a surface area that is acted on by the pressure prevailing in the control pressure chamber (52), the surface area being determined such that with a closed second control valve (70) when the control pressure chamber (52) is disconnected from the relief chamber (24), the force acting on the control piston (50) when the fuel injection valve (12) is open with only a partial stroke of the injection valve member (28) is sufficient to close the fuel injection valve (12) and when the fuel injection valve (12) is open with a maximal stroke of the injection valve member (28), this force is not sufficient to close the fuel injection valve (12).