Abstract: A fuel vapor treatment apparatus is provided with a fuel tank for storing fuel of an internal combustion engine, a canister for adsorbing fuel vapor generated in the fuel tank, a pump for reducing a pressure inside a detection target system including the fuel tank, a pressure detection sensor for detecting the pressure inside the detection target system, and a fluctuation detection unit for detecting a fluctuation width of the pressure inside the detection target system at the time when the pressure inside the detection target system is reduced to a predetermined pressure value.

Abstract: A fuel vapor processing device includes a canister, a first purge pipe that forms a first purge path that communicatively connects the inside of the canister and the inside of a fuel tank, a pressure pipe that forms a pressure detection path configured to communicatively connect a first switching valve and a pump, the first switching valve, a sealing valve disposed in the first purge pipe and configured to isolate the inside of the canister from the inside of the fuel tank, a differential pressure sensor, and an ECU. The differential pressure sensor is capable of detecting a difference between a pressure of the first purge path and a pressure of the pressure detection path. The ECU determines presence or absence of a fuel vapor leak while controlling the first switching valve, the pump, and the sealing valve based on a signal output from the differential pressure sensor.

Abstract: A fuel vapor treatment apparatus is provided with a fuel tank for storing fuel of an internal combustion engine, a canister for adsorbing fuel vapor generated in the fuel tank, a pump for reducing a pressure inside a detection target system including the fuel tank, a pressure detection sensor for detecting the pressure inside the detection target system, and a fluctuation detection unit for detecting a fluctuation width of the pressure inside the detection target system at the time when the pressure inside the detection target system is reduced to a predetermined pressure value.

Abstract: A first plate portion covers one opening of a pump chamber of a tubular portion, and a second plate portion covers the other opening of the pump chamber along a center axis of the tubular portion. A hole forming portion is equipped to an outside of the tubular portion to form a connection hole. A length of the hole forming portion along the center axis is less than or equal to a length of the tubular portion along the center axis. A first imaginary line connects a center of an outer opening of the connection hole with a point on the center axis. The first imaginary line intersects perpendicularly with the center axis. A length of the connection hole in a direction perpendicular to both the first imaginary line and the center axis is greater than a length of the connection hole along the center axis.

Abstract: A pressure sensor is provided in a purge pipe connecting a fuel tank to a canister, so that the pressure sensor outputs an electrical signal of a first sensor value depending on an inside pressure of the canister. A control unit calculates an estimated sealed pressure, which corresponds to the inside pressure of the canister in a condition that the canister and the fuel tank are in a sealed condition. The control unit determines that there is no leakage of fuel vapor, when the first sensor value is out of a first pressure range. The control unit determines that there is a small leakage of the fuel vapor, when the first sensor value is within the first pressure range but out of a second pressure range, wherein the second pressure range is smaller than the first pressure range. The control unit determines that there is a large leakage or a blocked-up condition in the purge pipe when the first sensor value is within the second pressure range.

Abstract: A fuel vapor processing device includes a canister, a first purge pipe that forms a first purge path that communicatively connects the inside of the canister and the inside of a fuel tank, a pressure pipe that forms a pressure detection path configured to communicatively connect a first switching valve and a pump, the first switching valve, a sealing valve disposed in the first purge pipe and configured to isolate the inside of the canister from the inside of the fuel tank, a differential pressure sensor, and an ECU. The differential pressure sensor is capable of detecting a difference between a pressure of the first purge path and a pressure of the pressure detection path. The ECU determines presence or absence of a fuel vapor leak while controlling the first switching valve, the pump, and the sealing valve based on a signal output from the differential pressure sensor.

Abstract: A pressure sensor is provided in a purge pipe connecting a fuel tank to a canister, so that the pressure sensor outputs an electrical signal of a first sensor value depending on an inside pressure of the canister. A control unit calculates an estimated sealed pressure, which corresponds to the inside pressure of the canister in a condition that the canister and the fuel tank are in a sealed condition. The control unit determines that there is no leakage of fuel vapor, when the first sensor value is out of a first pressure range. The control unit determines that there is a small leakage of the fuel vapor, when the first sensor value is within the first pressure range but out of a second pressure range, wherein the second pressure range is smaller than the first pressure range. The control unit determines that there is a large leakage or a blocked-up condition in the purge pipe when the first sensor value is within the second pressure range.

Abstract: A housing receiving a switching valve, a pressure sensor, and a pump includes a tubular portion having an inner wall provided with a support portion into which an attachment portion is inserted. The pump includes a pump portion and a motor portion which are connected to the attachment portion. The support portion receives an elastic member abutting on the attachment portion. The elastic member prevents a vibration generated due to an operation of the pump from being transmitted to the tubular portion. Since the pump is supported by a cover through a pressure detection pipe including a pressure detection passage and is supported by the tubular portion through the elastic member and the support portion, the pump prevents from vibrating by its weight. Therefore, a noise radiated out of the housing due to the vibration transmitted from the pump to the housing can be reduced.

Abstract: A first tubular portion has a cross sectional shape which is a non-perfect circle relative to an axis thereof. A second tubular portion is disposed concentrically with the first tubular portion. The second tubular portion has a cross sectional shape relative to its axis, which is a congruent shape of the cross sectional shape of the first tubular portion. A sealing member is disposed between the first tubular portion and the second tubular portion for sealing therebetween. The sealing member has a cross sectional shape of which length parallel to its axis is greater than length which is perpendicular to the axis.

Abstract: A valve element in a valve chamber is movable between an OFF position and an ON position to switch a flow quantity of fluid between a large flow quantity and a small flow quantity. The valve chamber has a fluid passage including an outer passage defined between an inner periphery of the valve chamber and an outer periphery of the valve element. The valve chamber has a throttle shape to decrease in inner diameter gradually from upstream toward downstream to decrease a minimum passage area of the fluid passage in a non-linear form. The valve chamber increases a differential pressure across the valve element in a linear form relative to a stroke of the valve element when the valve element moves from the OFF position toward the ON position.

Abstract: The vane pump has a pump chamber, in which a first inner plate and a second inner plate are movably accommodated at each of axial ends of a rotor. In a case that an electric motor is arranged at a lower side of the vane pump, the first inner plate is moved in a direction to the second inner plate by a force of gravity, so that the first inner plate is brought into contact with a first axial end of the rotor. As a result, an upper side axial open end of each pumping room, which is respectively defined by multiple vanes, is closed by the first inner plate. An amount of air leaking from one of the pumping rooms to the other pumping rooms can be reduced.

Abstract: A first plate portion covers one opening of a pump chamber of a tubular portion, and a second plate portion covers the other opening of the pump chamber along a center axis of the tubular portion. A hole forming portion is equipped to an outside of the tubular portion to form a connection hole. A length of the hole forming portion along the center axis is less than or equal to a length of the tubular portion along the center axis. A first imaginary line connects a center of an outer opening of the connection hole with a point on the center axis. The first imaginary line intersects perpendicularly with the center axis. A length of the connection hole in a direction perpendicular to both the first imaginary line and the center axis is greater than a length of the connection hole along the center axis.

Abstract: A first hole is connected through a first fluid chamber to an inflow hole. A first valve seat is formed around the first hole. A second fluid chamber is connected through a second hole to the first hole. An outflow hole is connected to the second fluid chamber. A second valve seat is formed around the second hole. A third valve seat is formed around the outflow hole. A first valve element is movable in the first fluid chamber to make contact with the first valve seat. A second valve element is movable in the second fluid chamber to make contact with the second valve seat or the third valve seat. A biasing member biases the second valve element toward the second valve seat. An outer peripheral passage is formed between an outer periphery of the second valve element and the second housing to enable flow therethrough.

Abstract: In a relief valve device, a positive-pressure relief valve opens a first valve port when pressure in a pressure chamber increases to a pressure that is equal to or higher than positive-pressure side valve-opening pressure. A negative-pressure relief valve opens a second valve port when pressure in the pressure chamber decreases to a pressure that is equal to or lower than negative-pressure side valve-opening pressure. When the positive-pressure relief valve is closed, a positive valve-opening pressure adjustment unit adjusts a set load of a positive-pressure spring according to an amount of an adjustment screw screwed in the pedestal plate. When the negative-pressure relief valve is closed, a negative valve-opening pressure adjustment unit adjusts a set load of the negative-pressure spring via the valve plate through forward or backward movement of the pedestal plate relative to a housing main body.

Abstract: A housing receiving a switching valve, a pressure sensor, and a pump includes a tubular portion having an inner wall provided with a support portion into which an attachment portion is inserted. The pump includes a pump portion and a motor portion which are connected to the attachment portion. The support portion receives an elastic member abutting on the attachment portion. The elastic member prevents a vibration generated due to an operation of the pump from being transmitted to the tubular portion. Since the pump is supported by a cover through a pressure detection pipe including a pressure detection passage and is supported by the tubular portion through the elastic member and the support portion, the pump prevents from vibrating by its weight. Therefore, a noise radiated out of the housing due to the vibration transmitted from the pump to the housing can be reduced.

Abstract: A first tubular portion has a cross sectional shape which is a non-perfect circle relative to an axis thereof. A second tubular portion is disposed concentrically with the first tubular portion. The second tubular portion has a cross sectional shape relative to its axis, which is a congruent shape of the cross sectional shape of the first tubular portion. A sealing member is disposed between the first tubular portion and the second tubular portion for sealing therebetween. The sealing member has a cross sectional shape of which length parallel to its axis is greater than length which is perpendicular to the axis.

Abstract: A valve element in a valve chamber is movable between an OFF position and an ON position to switch a flow quantity of fluid between a large flow quantity and a small flow quantity. The valve chamber has a fluid passage including an outer passage defined between an inner periphery of the valve chamber and an outer periphery of the valve element. The valve chamber has a throttle shape to decrease in inner diameter gradually from upstream toward downstream to decrease a minimum passage area of the fluid passage in a non-linear form. The valve chamber increases a differential pressure across the valve element in a linear form relative to a stroke of the valve element when the valve element moves from the OFF position toward the ON position.

Abstract: A first hole is connected through a first fluid chamber to an inflow hole. A first valve seat is formed around the first hole. A second fluid chamber is connected through a second hole to the first hole. An outflow hole is connected to the second fluid chamber. A second valve seat is formed around the second hole. A third valve seat is formed around the outflow hole. A first valve element is movable in the first fluid chamber to make contact with the first valve seat. A second valve element is movable in the second fluid chamber to make contact with the second valve seat or the third valve seat. A biasing member biases the second valve element toward the second valve seat. An outer peripheral passage is formed between an outer periphery of the second valve element and the second housing to enable flow therethrough.

Abstract: A first seal portion forms, when seated on a first seated position, a valve side chamber blocked from a relief chamber to have an equivalent fluid pressure to fluid pressure in a pressure-controlled chamber. The first seal portion causes, when lifted from the first seated position on increase in fluid pressure in the pressure-controlled chamber, the valve side chamber to disappear and to communicate the relief chamber with the pressure-controlled chamber. A second seal portion partitions, when seated on a second seated position, a part of the valve side chamber from the other part of the valve side chamber. The second seal portion is configured to be lifted from the second seated position on increase in fluid pressure in the pressure-controlled chamber, before the first seal portion is lifted from the first seated position.

Abstract: In a relief valve device, a positive-pressure relief valve opens a first valve port when pressure in a pressure chamber increases to a pressure that is equal to or higher than positive-pressure side valve-opening pressure. A negative-pressure relief valve opens a second valve port when pressure in the pressure chamber decreases to a pressure that is equal to or lower than negative-pressure side valve-opening pressure. When the positive-pressure relief valve is closed, a positive valve-opening pressure adjustment unit adjusts a set load of a positive-pressure spring according to an amount of an adjustment screw screwed in the pedestal plate. When the negative-pressure relief valve is closed, a negative valve-opening pressure adjustment unit adjusts a set load of the negative-pressure spring via the valve plate through forward or backward movement of the pedestal plate relative to a housing main body.