US Patent 7513241 Fuel injection valve with pressure gain

The invention relates to a fuel injection valve for intermittent fuel injection into the combustion chamber of internal combustion engines. A needle-shaped injection valve member (34) is arranged in the high-pressure fuel chamber (30) adjacent to the injection valve seat (32), said injection valve member co-operating with the injection valve seat (32) and defining, in a piston-type manner, the cylinder chamber (36) which is connected to the high-pressure inlet (26). The booster piston (28) is controlled by means of the control valve (34) embodied as a flat seat valve, increasing the pressure of the fuel in the high-pressure fuel chamber (30) for an injection, and thus lifting the injection valve member from the injection valve seat. In this way, the injection is carried out with increased pressure.