Liquid submerged portion fuel leakage diagnostic apparatus

摘要

A liquid submerged portion fuel leakage diagnostic apparatus includes a tank internal pressure detection portion; a liquid level detection portion; a reference-state liquid level extraction portion configured to extract, as a reference-state liquid level, a liquid level detected by the liquid level detection portion, when a tank internal pressure detected by the tank internal pressure detection portion becomes equal to a reference internal pressure; a fuel consumption detection portion configured to detect consumption of fuel in a fuel tank; and a fuel leakage diagnostic portion configured such that if the fuel consumption is not detected by the fuel consumption detection portion during a period between extraction timings at which the reference-state liquid levels are extracted by the reference-state liquid level extraction portion, the fuel leakage diagnostic portion diagnoses presence or absence of fuel leakage from a liquid submerged portion based on comparison of the reference-state liquid levels.

主权项

1. A liquid submerged portion fuel leakage diagnostic apparatus that diagnoses presence or absence of fuel leakage from a liquid submerged portion of a fuel tank for an internal combustion engine, the liquid submerged portion being submerged in fuel in the fuel tank, and the fuel tank being connected to a canister via a vaporized fuel passage and being configured such that an internal space of the fuel tank is able to be hermetically closed by a block valve that is provided in the vaporized fuel passage, the liquid submerged portion fuel leakage diagnostic apparatus comprising:
a pressure sensor that detects a tank internal pressure of the fuel tank; a liquid level sensor that detects a liquid level of the fuel in the fuel tank; and an electronic control unit configured to: extract, as a reference-state liquid level, the liquid level detected by the liquid level sensor, when the tank internal pressure detected by the pressure sensor becomes equal to a reference internal pressure; detect fuel consumption that is consumption of the fuel in the fuel tank; and diagnose the presence or absence of the fuel leakage from the liquid submerged portion, when the fuel consumption is not detected by the electronic control unit during a period between extraction timings at which a plurality of the reference-state liquid levels are extracted by the electronic control unit, based on comparison of the plurality of the reference-state liquid levels.