Abnormality determination apparatus and abnormality determination method for fuel supply system

Abstract

This apparatus detects, during a detection period from an intermediate timing (a time point t11) between respective compression top dead center timings of two of the cylinders that are successive to each other in ignition sequence to a timing (a time point t12) immediately before the start of fuel injection into that one of those cylinders which is later in ignition sequence, a fuel pressure by a pressure detection sensor that is provided in a manner corresponding to the cylinder that is later in ignition sequence, and determines, on the basis of a speed of decrease in the detected fuel pressure PQ, whether or not there has occurred an abnormality of fuel leakage.

Description

technical field [0001] The present invention relates to an abnormality determination device and an abnormality determination method designed for a fuel supply system and determining whether or not a fuel leakage abnormality has occurred in a fuel supply system that supplies fuel to each cylinder of an internal combustion engine. Background technique [0002] The fuel supply system of a direct injection internal combustion engine that directly injects and supplies fuel into each cylinder is equipped with pressure accumulation lines (common rail and delivery pipes) that store fuel that has been pressurized by pumping, and respectively Each cylinder is provided and connected to a fuel injection valve of a pressure accumulator container. These fuel injection valves are individually driven to open, whereby fuel is injected and supplied into the respective cylinders of the internal combustion engine at arbitrary timing. [0003] It should be noted here that an abnormality in whic...

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Problems solved by technology

[0005] For this reason, even in the case where the degree of drop in fuel pressure in the fuel supply system has become large due to detection of fuel pressure in order to determine whether or not a fuel leak abnormality has occurred, it is difficult to determine whether the drop in fuel pressure is attributable to fuel leak The occurrence of the anomaly can also be attributed to pressure pulsations in the fuel supply system

Accordingly, even when only the fuel pressure in the accumulator line is detected, it is difficult to determine with high precision whether or not a fuel leakage abnormality has occurred

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