Honda Motor Co., Ltd.

Yuichiro Murata

Daijiro Nakamura

Hiroki Ishikawa

Michinori Tani

Ikue Habu

Masahiro Fujii

Hidenori Sakai

Shuma Yatabe

A blockage diagnosis device includes a diagnosis unit that performs blockage diagnosis on a vent passage based on a change over time in an internal pressure of the vent passage in association with the operation of a negative pressure pump. A primary determination unit of the diagnosis unit makes a primary determination that the vent passage is blocked, if a first estimation volume Vis less than a preset threshold volume Vth. A secondary determination unit of the diagnosis unit makes a secondary determination that the vent passage is blocked, if the second estimation volume Vis less than the threshold volume Vth. If the primary determination indicating that the vent passage is blocked is made in the primary determination unit, and the secondary determination indicating that the vent passage is blocked is made in the secondary determination unit, the diagnosis unit determines that the vent passage is blocked.

Blockage diagnosis device

A blockage determination portionof a blockage detection systemdetermines that no blockage has occurred in a purge line, if a flow rate V of an inner fluid Fi exceeds a flow rate threshold THv while an internal pressure Pi of the purge lineis reduced from a first pressure value Pto a second pressure value P, for example. The blockage determination portiondetermines that a blockage has occurred in the purge line, if the flow rate V of the inner fluid Fi falls below the flow rate threshold THv after the internal pressure Pi is reduced from the first pressure value Pto the second pressure value P

Blockage detection system and blockage detection method

Disclosed is a fuel level estimation device including: an information acquiring unit acquiring information about a closed system internal pressure of a closed fuel vapor system including the fuel tank, a vent passage, and a canister; a flow rate controlling unit controlling, by actuating a negative pressure pump, a flow rate of fuel vapor-containing gas in the closed fuel vapor system; a fuel level estimating unit estimating a fuel level based on a total volume of the closed fuel vapor system and an occupied volume of the gas. The fuel level estimating unit estimates the occupied volume of the gas by using a change in a closed system internal pressure before and after the closed fuel vapor system is subjected to pressure-reducing treatment for a predetermined interval and a reference discharging rate when the gas is subject to the pressure-reducing treatment. An abnormality diagnostic apparatus is also disclosed.

Fuel level estimation device and abnormality diagnostic apparatus for closed fuel vapor system

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Wako, Japan

Yuichiro Murata