HP pump for fuel injection system has I-valve with valve needle having compensating orifice accommodating pin with cross sectional area corresponding to difference between that of valve needle and that of compensating piston

摘要

The high pressure pump has a switching valve (1) in the form of an I-valve, the valve needle (3) of which has a compensating orifice (13) accommodating a pin (25), the cross sectional area of which corresponds to the difference between the cross sectional area of the valve needle and cross sectional area of a compensating piston (19) constructed on the valve needle. The pin is supported on a part (26) of the valve housing (2) independent of the movement of the valve needle.