Patent ID: 7017553
Filing Date: 2006-03-28
Classification: F02M

Abstract:
1. In a fuel injection apparatus for an internal combustion engine comprising a high-pressure fuel pump ( 10 ) and a fuel injection valve ( 12 ) connected to it for each cylinder of the engine, the high-pressure fuel pump ( 10 ) having at least one pump piston ( 18 ) that is driven into a stroke motion by the engine and delimiting a pump working chamber ( 22 ) that is supplied with fuel from a fuel tank ( 24 ), the fuel injection valve ( 12 ) having a pressure chamber ( 40 ) connected to the pump working chamber ( 22 ) and at least one first injection valve element ( 28 ), which controls at least one first injection opening ( 32 ) and, actuated by the pressure prevailing in the pressure chamber ( 40 ), can be moved in an opening direction ( 29 ) counter to a closing force in order to open the at least one injection opening ( 32 ), with a control valve ( 68 ) that at least indirectly controls a connection ( 66 ) of the pump working chamber ( 22 ) to a relief to chamber ( 24 ) and to a pressure source ( 23 ) in order to fill the pump working chamber ( 22 ) during the intake stroke of the at least one pump piston ( 18 ), the improvement wherein the high-pressure pump ( 10 ) has two pump pistons ( 18 , 118 ), including a first pump piston ( 18 ) inside of which the second pump piston ( 118 ) is guided so it can slide in an at least approximately coaxial fashion, the two pump pistons ( 18 , 118 ) delimiting the pump working chamber ( 22 ), wherein the first pump piston ( 18 ) is driven into a stroke motion, wherein the two pump pistons ( 18 , 118 ) can optionally be coupled to each other and move as a unit during the delivery stroke or the second pump piston ( 118 ) can be fixed in a passive position so only the first pump piston ( 18 ) executes a delivery stroke, wherein the fuel injection valve ( 12 ) has a second injection valve element ( 128 ), which is guided in a sliding fashion inside the hollow first injection valve element ( 28 ), controls the at least one second injection opening ( 132 ), and can be moved by the pressure prevailing in the pressure chamber ( 40 ) in an opening direction ( 29 ) counter to a closing force, wherein the second injection valve element ( 128 ) is at least indirectly acted on by the pressure prevailing in a fuel-filled control pressure chamber ( 52 ; 252 ), and wherein the control pressure chamber ( 52 ; 252 ) has a connection ( 53 ; 253 ) to the pump working chamber ( 22 ) controlled by the second pump piston ( 118 ), wherein the control pressure chamber ( 52 ; 252 ) is disconnected from the pump working chamber ( 22 ) when the second pump piston ( 118 ) is disposed in its passive position.