Fuel pressure waveform acquiring equipment for fuel injection system

Abstract

A fuel pressure waveform acquiring equipment comprises the following components: a pressure waveform acquiring device which is used for acquiring a first pressure waveform detected through a fuel pressure sensor as a multi-segment injection pressure waveform that occurs in performing multi-segment fuel injection; a model waveform storing device which is used for storing a standard model waveform as a second pressure waveform, wherein the second pressure waveform occurs when target injection which is earlier than a second segment or a later period in the multi-period ejection is performed imaginarily; a waveform extracting device which is used for subtrating the model waveform from the multi-segment injection pressure waveform for extracting a third pressure waveform that is caused by the target injection; and a compensating device which is used for compensating the model waveform through damping the model waveform for a certain damping value, wherein the damping value depends on injection interval between the earlier injection and the target injection.

Description

technical field [0001] The present invention relates to a device for acquiring, as a pressure waveform, a temporal change in fuel pressure caused by fuel injection from a fuel injection valve of an internal combustion engine. Background technique [0002] In order to precisely control the output torque and discharge state of the internal combustion engine, it is necessary to control the injection state including the injection amount and injection timing of fuel injected from the injection hole of the fuel injection valve. Japanese Patent Application Laid-Open Nos. 2010-3004 (Patent Document 1) and 2009-57924 (Patent Document 2) describe the use of a fuel pressure sensor to detect pressure in a fuel supply passage leading to a fuel injection hole caused by fuel injection. A technique that changes the fuel pressure over time to thereby detect the actual fuel injection state. [0003] For example, the actual fuel injection start timing can be detected by detecting the timing a...

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Problems solved by technology

[0006] However, the inventors of the present application have found through various experiments that the pressure caused only by the n-th stage injection (target injection) cannot be accurately acquired by simply subtracting the model waveform CALn-1 from the detected pressure waveform W. Waveform Wn

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