Patent ID: 7513440

Claim:
A fuel injection device ( 1 ) adapted to be connected to a high-pressure source ( 2 ), said fuel injection device ( 1 ) comprising: a multi-part injector body ( 4 ; 8 , 9 , 10 ); an injection valve clement ( 24 ) in said multi-part injector body for blocking or unblocking at least one injection opening ( 25 ); a nozzle chamber ( 23 ) enclosing the injection valve element in the region of a pressure shoulder provided on the injection valve element ( 24 ); a pressure booster ( 11 ) provided in said multi-part injector body, said pressure booster ( 11 ) comprising a pressure booster piston ( 14 ), a working chamber ( 12 ) on one side of said piston and a differential pressure chamber ( 17 ) on an opposite side of said pressure booster piston, said pressure booster piston ( 14 ) sealing the working chamber ( 12 ) off from the differential pressure chamber ( 17 ), said pressure booster piston ( 14 ) being actuated by means of a pressure change in said differential pressure chamber ( 17 ), a high-pressure chamber ( 19 ) defined, at least in part, by an end face ( 14 a ) of the pressure boosting a piston ( 14 ); a nozzle chamber inlet ( 22 ) hydraulically connecting the nozzle chamber ( 23 ) with the high-pressure chamber ( 19 ); a control chamber ( 20 ) hydraulically connected to the high-pressure chamber ( 19 ); an on-off valve ( 5 , 70 ) for actuating said fuel injection device ( 1 ); a central control line ( 31 ) extending through said pressure booster piston ( 14 ), said pressure change in the differential pressure chamber ( 17 ) of the pressure booster ( 11 ) occurring via the central control line ( 31 ); and wherein the central control line ( 31 ) extends essentially coaxially to an axis of symmetry of the pressure booster piston ( 14 ), wherein the central control line ( 31 ) extends through the working chamber ( 12 ) of the pressure booster ( 11 ) and further comprising a high-pressure-tight connection ( 33 , 50 , 61 ) for sealing off said central control line ( 31 ) from said working chamber ( 12 ).