Fuel injection nozzle and method of manufacture

摘要

An injection nozzle (10), for use in a fuel injector for an internal combustion engine, has an inner valve needle (26) which is engageable with an inner valve seating (24, 58) to control fuel delivery through one or more first nozzle outlets (14), and an outer valve (28) which is engageable with an outer valve seating (24, 70) to control fuel delivery through one or more second outlets (16). The outer valve (28) is provided with a valve bore (36) within which at least a part of the inner valve needle (26) is received. Coupling means (46, 48) are provided for coupling movement of the inner valve needle (26) to the outer valve (28) in circumstances in which the inner valve needle (26) is moved away from the inner valve seating (24, 58) through an amount exceeding a predetermined threshold amount (D). This allows the outer valve (28) to be lifted away from the outer valve seating (24, 70) to provide an increased injection rate. If only a reduced injection rate is required the inner valve needle (26) need only be lifted through an amount less than the threshold amount.