Patent ID: 7934668

Claim:
A fuel injector for use in an internal combustion engine, comprising: a nozzle body provided with a nozzle bore and at least one set of one or more outlets for fluid; an outer valve member received within the nozzle bore and being engageable with a first seating region of the nozzle body to control the flow of a first fluid from a first delivery chamber to at least one set of outlets, the outer valve member being provided with an outer valve bore; an inner valve member received within the outer valve bore and being engageable with a second seating region of the nozzle body to control the flow of a second fluid from a second delivery chamber to at least one set of outlets; an injection control chamber for the first fluid; a pressure control arrangement for controlling the pressure of fluid in the control chamber; a first surface associated with the inner valve member, the first surface being exposed to fluid pressure within the injection control chamber; and a second surface associated with the outer valve member, the second surface being exposed to fluid pressure within the injection control chamber; wherein, when the injection control chamber is at an intermediate fluid pressure, the inner and outer valve members are in engagement with their respective seating regions; and wherein the first and second surfaces are arranged such that when the pressure of fluid within the injection control chamber is increased from the intermediate fluid pressure to a relatively high pressure, one of the outer valve member or the inner valve member is caused to disengage its respective seating region, and when the pressure of fluid within the injection control chamber is decreased from the intermediate fluid pressure to a relatively low pressure, the other of the outer valve member or the inner valve member is caused to disengage its respective seating region.