Aisan Kogyo Kabushiki Kaisha

Yuya Tanida

Mariko Kawase

Keita Suzuki

A leakage detector for a fuel vapor processing system having a canister. The leakage detector includes a sealing system and a control unit. The sealing system is connected to the canister and is configured to sealingly close an inspection area, which includes the canister. The control unit is implemented by at least one programmed processor. The control unit is configured to calculate an amount of fuel vapor in the canister. The control unit is also configured to select a leakage detection method from the group consisting of a positive pressure type and a negative pressure type. The selection is made based on the calculated amount of the fuel vapor in the canister. The control unit is further configured to perform the leakage detection method in response to temporal changes in an internal pressure of the inspection area closed by the sealing system.

Leakage detector

A leakage detector for a fuel vapor processing system includes a pressure sensor and a control unit. The pressure sensor is configured to measure an internal pressure of the fuel vapor processing system. The control unit is configured to calculate changes of a fuel vapor pressure from a saturation vapor pressure curve of the fuel vapor, a fuel vapor concentration of the fuel vapor in a gaseous layer within the fuel vapor processing system, and a convective velocity in the gaseous layer, to correct a reference pressure for leakage detection based on the changes of the fuel vapor pressure so as to calculate a corrected reference pressure, and to compare the internal pressure measured by the first pressure sensor to the corrected reference pressure so as to determine whether any of the fuel vapor has leaked from the fuel vapor processing system.

A fuel-feeding device may include a fuel tank storing fuel therein, a fuel pump configured to feed the fuel in the fuel tank to an engine through a fuel-feeding conduit, an aspirator configured to generate a negative pressure therein using a flow of the fuel flowing through a branched conduit branched from the fuel-feeding conduit, a negative pressure sensor configured to detect the negative pressure generated by the aspirator, and a control device configured to control a revolution speed of the fuel pump. The control device is configured to determine a sign of vapor generation in the fuel stored in the fuel tank based on detection information of the negative pressure sensor.

Fuel-feeding device

A leakage detector includes a pressure sensor for detecting the pressure in a detecting target area of the fuel vapor treatment system and a controller. The controller measures the pressure in the detecting target area at a certain point in time. The controller then determines whether the measured pressure satisfies a condition for leakage detection by a vapor pressure device. When the controller determines that the condition is satisfied, the controller selects the vapor pressure device. When the controller determines that the condition is not satisfied, the controller predicts the change in vapor pressure at a subsequent temperature based on a saturated vapor pressure characteristic of the fuel. If it is determined the pressure in the detecting target will satisfy a predetermined condition, the controller selects a pressure application device. If it is determined that the predetermined condition will be satisfied, the controller selects the vapor pressure device.

Leakage detector for fuel vapor treatment system

A failure diagnostic device is configured to determine saturated vapor pressures of a fuel within a fuel tank. In a fuel vapor processing apparatus, some or all of the passages and spaces into which the fuel vapor flows into the fuel vapor processing apparatus are closed to the atmosphere. In this condition, the failure diagnostic device determines a plurality of saturated vapor pressure characteristics over time. The failure diagnostic device is configured to diagnose whether or not a leakage or a blockage failure in the fuel vapor processing apparatus is present. The failure diagnostic device determines a Reid vapor pressure (RVP) based on each of the plurality of determined saturated fuel vapor pressure characteristic and diagnoses whether or not a failure is present in accordance with a change in these RVPs over time.

Failure diagnostic device for fuel vapor processing apparatus

A concentration measuring device includes a circulation passage, an aspirator, a differential pressure sensor, and a control unit. The aspirator is disposed in a fuel tank and is connected to the circulation passage. While a gas flows from a gaseous layer within a fuel tank through the circulation passage due to a negative pressure generated in the aspirator, the differential pressure sensor measures a pressure difference of the gas within the circulation passage between an upstream side of a narrowed part, having a narrower passage area than an adjacent portion of the circulation passage, and a downstream side of the narrowed part. The control unit is configured to calculate a density of the fuel vapor from the pressure difference of the gas and to calculate a concentration of the fuel vapor from the density of the fuel vapor.

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Obu, Japan

Yuya Tanida