Fuel injection control system

Abstract

An engine has cylinders, a fuel injection unit with a valve operable in response to a valve control signal to cause fuel to be injected into the cylinders, and a control unit which generates the valve control signal. A method of controlling the valve includes sensing a time associated with movement of the valve corresponding to start of a fuel injection event, and modifying the valve control signal as a function of the sensed time. The method further includes determining a rise time of the valve control signal, determining a valve operation delay time as a function of the rise time, determining a difference time representing a difference between a desired valve operation time and the sensed time, comparing the valve operation delay time to the difference time, and adjusting timing of the valve control signal as a function of the comparison. The method, also, as a function of the comparison, varies individual valve control signal parameter values, each associated with a particular cylinder of the engine, generates a sum value SUM representing a sum of the individual parameter values for all the cylinders, generates an average parameter AVE by dividing the SUM value by the number of cylinders, generates updated individual parameter values by subtracting the AVE value from previous individual parameter values, and modifies the valve control signal as a function of the updated individual parameter values.

Dependencies are inferred from the claim text.