Fuel injector with control valve to control the pressure in the needle control chamber

DRIVE June 15, 2005

Source

A fuel injector (10) for use in an internal combustion engine, comprising a supply passage (24) for high pressure fuel and an injection nozzle (25) for receiving high pressure fuel. The injection nozzle (25) includes a valve needle (26) which is engageable with a valve needle seating (28) to control fuel delivery from the injector (10). A surface associated with the valve needle is exposed to fuel pressure within a control chamber (42) and a first restricted flow path (44, 44a) provides communication between the supply passage (24) and the control chamber (42). A supplementary flow means (47, 46) also provides communication between the supply passage (24) and the control chamber (42) under the control of a control valve (48), so as to allow high pressure fuel to flow from the supply passage (24) into the control chamber (42) through two flow paths (44, 46, 47) when it is required to terminate an injection of fuel.