Honda Motor Co., Ltd.

Daijiro Nakamura

Hiroki Ishikawa

Michinori Tani

Ikue Habu

Yuichiro Murata

Masahiro Fujii

Hidenori Sakai

Shuma Yatabe

Occlusion diagnosis of a vent passage is executed with high accuracy based on an estimated value of the volume of a sealed space. An occlusion diagnosis device includes a diagnosis unit for the diagnosis. An occlusion diagnosis unit of the diagnosis unit executes the occlusion diagnosis, based on whether or not an estimated volume of a sealed space of a fuel-vapor sealing system exceeds a volume threshold. The occlusion diagnosis determines that the vent passage is suspected of being occluded if the estimated volume is equal to or less than the volume threshold, while diagnoses that the vent passage is not occluded if the estimated volume exceeds the volume threshold. If it is determined that the vent passage is suspected of being occluded, the occlusion diagnosis unit causes the occlusion diagnosis of the vent passage to remain incomplete until a cumulative exhaust amount of fluid exceeds an exhaust amount threshold.

Occlusion diagnosis device

A blockage detection device opens a purge valve in a state where a negative pressure pump is operated. The negative pressure pump is connected to a downstream side of a canister with respect to a fuel tank, and reduces pressure in a device internal space. The blockage detection device calculates gas information (volume V, for example) of the device internal space on the basis of variation of internal pressure before and after the purge valve is opened. The blockage detection device detects a blockage in a vent line using the calculated gas information.

Blockage detection device and blockage detection method

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.

Growing community of inventors

Wako, Japan

Daijiro Nakamura