FUEL-INJECTION VALVE FOR INTERNAL COMBUSTION ENGINES

摘要

The invention relates to a fuel-injection valve comprising a valve member (10) that co-operates with a valve seat (16) to control injection openings (20). The valve member (10) is configured in a bore (7) in a section facing away from the combustion chamber and is surrounded by a pressure chamber (12) that can be filled with pressurised fuel. The valve member (10) is subjected to a closing force in the direction of the valve seat (16) by a spring (27) located in a spring chamber (25) and is raised from the valve seat (16) at a corresponding opening pressure in the pressure chamber (12) by the hydraulic pressure on an exposed annular area (11) configured on the valve member (10), thus opening the injection openings (20), the fuel being injected separately in a primary injection and a subsequent secondary injection. The pressure chamber (12) and the spring chamber (25) are connected by a throttle connection in such a way that the pressure in the otherwise closed spring chamber (25) increases during the primary injection and raises the opening pressure of the secondary injection by means of the additional hydraulic force on the valve member (10), the pressure in the spring chamber returning to the initial value (25) by the start of the next injection cycle.