Fuel injection system for combustion engine

The high-pressure fuel supply (5) is connected (3) to a valve body (31) of a control valve (30). A control piston (70) moves up and down in the valve body and may be controlled by a switching valve (40). It may control a connection (58) to a chamber (26) under a spring-loaded (18) piston (22). The piston acts as a hydraulic amplifier (21) with a smaller diameter piston (23) pressurizing a second chamber (25) connected (51) to the nozzle pressure chamber (14).