Abstract: A fuel injection apparatus for use in an internal combustion engine includes a fuel injector having a valve member which is operable to control injection of fuel through an injector outlet, a first supply path having a first path length for delivering fuel to an injector control chamber, a second supply path having a second path length for delivering fuel to an injector delivery chamber and a control valve for controlling fuel pressure within the injector control chamber so as to control movement of the valve member. An actuation means is arranged to vary at least one of the first and second path lengths in response to one or more injection parameters. Varying the first and/or second path length enables resonant pressure pulses within the control chamber and/or delivery chamber to be optimized so as to minimize the pressure differential across the valve needle at the instant of closure of the control valve to terminate injection, thus reducing needle closure response.

Abstract: A fuel injection apparatus for use in an internal combustion engine includes a fuel injector having a valve member which is operable to control injection of fuel through an injector outlet, a first supply path having a first path length for delivering fuel to an injector control chamber, a second supply path having a second path length for delivering fuel to an injector delivery chamber and a control valve for controlling fuel pressure within the injector control chamber so as to control movement of the valve member. An actuation means is arranged to vary at least one of the first and second path lengths in response to one or more injection parameters. Varying the first and/or second path length enables resonant pressure pulses within the control chamber and/or delivery chamber to be optimised so as to minimise the pressure differential across the valve needle at the instant of closure of the control valve to terminate injection, thus reducing needle closure response.