Patent ID: 6227168
Filing Date: 2001-05-08
Classification: F02D,Y02T

Abstract:
A fuel-injection method for an engine, comprising the steps of; storing a common rail with a fuel delivered by the means of a fuel-supply pump, injecting the fuel from the common rail into combustion chambers through injection holes formed in injectors, which are actuated with injection command signals, making a decision about a basic desired injection timing in compliance with engine operating conditions at present by using a basic desired injection timing data which is previously defined in accordance with the engine operating conditions, finding an injection lag spanning from an output timing of the injection command signal to an injection timing at which the fuel injection is made to start, by a function previously defined of a variable of a time at which a pressure drop starts in the common rail pressure at least after the start of the fuel injection, and making a decision about the output of the injection command signal in accordance with the basic desired injection timing and the injection lag,wherein the timing of the start of the pressure drop in the common rail pressure is defined as a time at which a difference between a pressure data and an approximate straight line is the largest value, the pressure data being obtained by filtering process of waveforms of the detected common rail pressure, and the approximate straight line being calculated, with respect to a curve represented on coordinates of the time and pressure data, by the use of the pressure data spanning from a preselected time before the pressure drop in the common rail pressure to a time of at least the first smallest value after the start of the pressure drop.