Control method

摘要

A control method for controlling the timing of fuel injection in a fuelling system for an engine comprising a fuel injector supplied with fuel from a source of fuel at high pressure, comprises varying a drive current which is supplied to the fuel injector at a first time so as to initiate or terminate a primary injection of fuel and monitoring the pressure of fuel within the source so as to detect when a variation in fuel pressure occurs. A time delay is measured, which represents the difference in time between the first time and a second, later time at which a variation in fuel pressure within the source is detected.