Patent ID: 8437942
Filing Date: 2013-05-07
Classification: F02D,F02M,Y02T

Abstract:
1. A fuel injection characteristic sensing device used in a fuel injection system having a pressure accumulator that accumulates fuel to be supplied to a predetermined injector under pressure and at least one fuel pressure sensor for sensing pressure of the fuel flowing through an inside of a fuel passage extending from the pressure accumulator to a fuel injection hole of the injector at a predetermined point downstream of a neighborhood of a fuel discharge hole of the pressure accumulator with respect to a fuel flow direction, the fuel injection characteristic sensing device comprising: a fuel pressure sensing means for sequentially sensing the fuel pressure at the predetermined point corresponding to the fuel pressure sensor based on at least one output of the at least one fuel pressure sensor; an injection timing detecting means for detecting a predetermined timing in a series of operations concerning fuel injection of the injector based on the fuel pressure sequentially sensed by the fuel pressure sensing means; a differentiating means for applying first or higher order differential processing to fuel pressure data sequentially sensed by the fuel pressure sensing means to obtain an inflection point of a pressure transition as a timing at which a differential value indicates a predetermined changing mode, wherein the injection timing detecting means detects all of an injection start timing, a maximum injection rate reaching timing at which an injection rate is maximized, a timing at which the injection rate starts decreasing after reaching the maximum injection rate and an injection end timing of the injector based on the pressure inflection point obtained by the differentiating means, and wherein the injection timing detecting means calculates a correction coefficient relating to each of the injection start timing, the maximum injection rate reaching timing, the timing at which the injection rate starts decreasing after reaching the maximum injection rate and the injection end timing based on the timings.