Patent attributes
The invention provides an injection nozzle for an internal combustion engine, the injection nozzle (2) including an outer valve member (8) received within a bore (6) provided in a nozzle body (4) and being engageable with a first seating region (20) to control fuel flow from a first delivery chamber (32) to a first nozzle outlet (22), an inner valve member (44) slidable within an outer valve bore (34) provided in the outer valve member (8) and being engageable with a second seating region (46) to control fuel flow from a second delivery chamber (62) to a second nozzle outlet (48), a lifting arrangement (80) associated with the outer valve member (8) such that movement of the outer valve member (8) is transmitted to the inner valve member (44) when the outer valve member (8) is moved through a distance greater than a predetermined distance (L), and a control chamber (7) arranged to receive pressurised fuel, in use. A first surface (10, 11) associated with the outer valve member (8) defines a first effective surface area and a second surface (38a) associated with the inner valve member (44) defines a second effective surface area, both the first and second effective surface areas being exposed to fuel pressure within the control chamber (7), wherein the first effective surface area is greater than the second effective surface area such that, following a decrease in fuel pressure within the control chamber (7), the outer valve member (8) disengages the first seating region (20) before the inner valve member (44) disengages the second seating region (46), and on re-pressurisation of the control chamber (7) a force is applied to the first effective surface area so that the outer valve member (8) re-engages with the first seating region (20) simultaneously with the inner valve member (44) re-engaging with the second seating region (46).
