Abstract: A fuel vapor leakage check module has a canister port which is provided so that the port can be opened to the air and is connected to the interior of a fuel tank through a canister for absorbing fuel vapor produced in the fuel tank. A pump depressurizes or pressurizes the interior of the fuel tank through the canister port. A connecting passage which is coaxially provided in the canister port, is connected to the canister port. The connecting passage is depressurized or pressurized by the pump. A standard orifice is coaxially provided in the connecting passage and reduces the passage area of the connecting passage.

Abstract: A fuel vapor leak check module has a pressure sensor and a pump driven by a brushless motor. The pressure sensor is disposed at a place opposite to the inlet. A sensor room in which the pressure sensor is disposed communicates with the inlet of the pump through a pressure introducing passage and a pump-passage. Even if a pressure fluctuation arises at an inlet of the pump, a pressure fluctuation of the pressure in the fuel tank is restricted. Furthermore, the control circuit for the brushless motor is cooled by air flowing through a discharge passage. The sensor room is restricted from the discharge passage so that the discharged air hardly flows into the pressure room to enhance the accuracy of fuel vapor detection.

Abstract: A housing of a fuel vapor leak check module is arranged close to a canister by inserting a canister port into the canister. A distance between the canister and the leak check module is reduced. A centerline of the canister port is approximately parallel to a centerline of an atmospheric vent port. A brushless motor of which axial length is relatively short drives a pump so that the housing is formed stepwise at the side opposite to the canister. A connector is disposed on the housing accommodating the pump to reduce a dead space.

Abstract: A rotor includes a plurality of vanes and is connected to a rotatable shaft of a motor arrangement. A casing includes a pump chamber and elongated holes. The pump chamber receives the rotor in such a manner that the rotor is eccentric to the pump chamber. Each elongated hole penetrates through the casing and has an elongated cross section. A major axis of the elongated cross section of each elongated hole extends in a direction of eccentricity of the rotor relative to the pump chamber. Each bolt is received through a corresponding elongated hole of the casing and is threadably engaged with a mount to connect the casing to the mount. The casing holds each bolt in a minor axial direction of the elongated cross section of the corresponding elongated hole to limit substantial movement of the male threaded screw member in the minor axial direction of the elongated hole.

Abstract: An apparatus detects leak in a fuel vapor treatment system which is referred to as an evaporation system. The apparatus measures a required time T2 that is required for decreasing pressure in the evaporation system from P0 to P1 while opening a base leak hole that provides known amount of leak. Then, a required time T1 that is required for decreasing pressure from P0 to P1 is measured while closing the base leak hole. The apparatus compares the required times T1 and T2 in order to detect a leak other than the base leak hole. In this process, a specified coefficient that is defined in accordance with the base leak hole is taken into consideration. It is possible to detect the leak of the evaporation system with high accuracy even when the amount of remaining fuel is extremely large.

Abstract: A pressure-changing device of a leak check system for a fuel vapor treatment system has a pressure chamber formed in a peripheral space of a communicating path connecting a pump with an electromagnetic valve, the pressure chamber being deviated from flow delivered by the pump. The electromagnetic valve is opened to connect the communicating path with a canister. Then, a purge valve is closed and the pump is turned on to change pressure in a fuel vapor path. A pressure sensor attached on a side wall of the pressure chamber detects pressure in the communicating path to determine pressure in the fuel vapor path. The leak check system judges existence of leak in the fuel vapor treatment system from pressure in the fuel vapor path.

Abstract: When purge control of fuel vapor, which is released from a fuel tank and is then adsorbed and retained in a fuel adsorption layer of a canister, is performed through ON/OFF control of a purge valve, ON/OFF of a heater plate received in the canister is controlled based on a purge fuel vapor concentration estimated through air-fuel ratio control operation of an engine. In this way, a sensor for measuring the purge fuel vapor concentration of the fuel vapor conducted from the canister to an intake passage of the engine can be eliminated.

Abstract: An apparatus detects leak in a fuel vapor treatment system which is referred to as an evaporation system. The apparatus measures a required time T2 that is required for decreasing pressure in the evaporation system from P0 to P1 while opening a base leak hole that provides known amount of leak. Then, a required time T1 that is required for decreasing pressure from P0 to P1 is measured while closing the base leak hole. The apparatus compares the required times T1 and T2 in order to detect a leak other than the base leak hole. In this process, a specified coefficient that is defined in accordance with the base leak hole is taken into consideration. It is possible to detect the leak of the evaporation system with high accuracy even when the amount of remaining fuel is extremely large.

Abstract: An evaporated fuel purge system has a fuel tank, an adsorption filter and a purge control valve. The evaporated fuel purge system is pressurized and depressurized through a venting flow path by a pump, so that the state of leakage therefrom is thereby inspected. For this inspection, a motor unit for driving the pump which applies or reduces pressure, an in-vehicle battery and a voltage control circuit which controls a battery voltage to a predetermined voltage and supplies the motor unit with a current are provided. The voltage control circuit is located in a pump chamber which forms a part of air outlet passage.

Abstract: An evaporated fuel purge system has a fuel tank, an adsorption filter and a purge control valve. The evaporated fuel purge system is pressurized and depressurized through a venting flow path by a pump, so that the state of leakage therefrom is thereby inspected. For this inspection, a motor unit for driving the pump which applies or reduces pressure, an in-vehicle battery and a voltage control circuit which controls a battery voltage to a predetermined voltage and supplies the motor unit with a current are provided. A switchover valve is integrated with the pump, the motor and the like into a single module.

Abstract: In a double-acting diaphragm pump, a diaphragm is provided to divide a pump body into two pump chambers. An electromagnetic-type reciprocating actuator is provided in a housing hermetically integrated with the pump body. Different from an electric-type pump, the actuator is integrally mounted on the double-acting diaphragm pump and an entire system is hermetically sealed. Therefore, even if the diaphragm is torn, fuel vapor is prevented from leaking outside. Additionally, four check valves are provided to control the discharge of vapor from a canister side to an engine side. These check valves may employ a reed to control vapor flow or a spring and plate to control flow. In addition, since the pump may be a double-acting type, a large discharge volume is obtained and the pump can be made smaller. The pump may also be a non double-acting type.

Abstract: When detection of an abnormality in a fuel vapor treating system is executed, a vapor zone including a fuel tank and a canister is sealed. The sealed vapor zone is pressurized. Whether fuel vapor is leaking from the vapor zone is determined based on the pressure in the sealed vapor zone. A canister valve selectively connects a canister with and disconnects the canister from the atmosphere. During the abnormality detecting procedure, an electronic control unit (ECU) shuts the canister valve. After the abnormality detecting procedure is ended, the ECU sends a control signal having a predetermined frequency to the canister valve, thereby gradually increasing the opening size of the canister valve. Accordingly, the pressure in the vapor zone is gradually lowered to the atmospheric pressure. This prevents fuel vapor adsorbed by the canister from being released to the atmosphere.

Abstract: A fuel vapor leakage inspection apparatus utilizes a fuel tank, an adsorption container which houses an adsorbent for adsorbing fuel vapor generated in the fuel tank, and an exhaust device for communicating between the adsorption container and an intake pipe. Furthermore, the apparatus utilizes a pressure means that pressurizes or depressurizes a fuel vapor path formed from the fuel tank through the adsorption container to the exhaust device. A leakage detection means detects leakage from the fuel vapor path after the fuel vapor path is pressurized or depressurized by the pressure means while a calculation means calculates an amount of fuel vapor adsorbed, and a control means determines if the pressure means should execute leakage inspection of the fuel vapor path in accordance with the amount of the fuel vapor calculated by the calculation means.

Abstract: A canister for a vehicular evaporative emission control system has activated carbon and heating means. The heating means heats the activated carbon particles. The activated carbon particles are characterized by the following properties. Pore volume is 0.28 ml/ml or more. Average pore radius is in a range of 10.5 Angstroms to 12.0 Angstroms. Particle diameter of the activated carbon is in a range of 1.0 mm to 1.6 mm. The activated carbon particles provide high performances on both of adsorption and desorption.

Abstract: In a vane pump, a rotor chamber is defined within a housing that includes a ring and first and second plates. An inlet is communicated with the rotor chamber through an intake groove, and an outlet is communicated with the rotor chamber through a discharge groove. A rotor, which has a plurality of radially reciprocable vanes, is rotatably received in the rotor chamber, and a plurality of volume variable pump chambers is defined by the vanes between an inner peripheral wall surface of the housing and an outer peripheral surface of the rotor. The discharge groove includes a first end and a second end, and the second end is positioned away from the first end in the rotational direction of the rotor. The outlet extends directly from the second end of the discharge groove.

Abstract: An evaporative emission leak detection system provides for detecting a leakage of a fuel vapor evaporating in a fuel tank by using a pressure difference between an inside and outside of the fuel tank. The system includes a pump for providing the pressure difference between the inside and outside of the fuel tank, a brushless motor for operating the pump, a first passage connecting to the fuel tank, a second passage connecting to the outside of the fuel tank, and a switching device for switching connections between the pump and at least one of the first passage and the second passage. The first passage has an adsorbent for adsorbing the fuel vapor. This system ensures a long life time and high accuracy of the leak detection.

Abstract: An evaporated fuel adsorbed by an adsorbing member of a canister is compulsively desorbed by driving of a purge pump and is introduced into an intake passage of an internal combustion engine. In this instance, intake pulsation of the intake passage of an internal combustion engine is introduced into a driving chamber of the purge pump and a partition is moved, so that the capacity of a pump chamber is varied. In other words, the purge pump conducts its pump operation by utilizing the movement of the partition resulting from the introduction of intake pulsation of the intake passage of the internal combustion engine, and a power loss can be thus reduced. When a pressure difference is small between the intake pressure inside the intake passage of the internal combustion engine and the pressure on the canister side, too, a desired purge flow rate can be secured in accordance with the operating condition of the internal combustion engine.

Abstract: An apparatus detects leak in a fuel vapor treatment system which is referred to as an evaporation system. The apparatus measures a required time T2 that is required for decreasing pressure in the evaporation system from P0 to P1 while opening a base leak hole that provides known amount of leak. Then, a required time T1 that is required for decreasing pressure from P0 to P1 is measured while closing the base leak hole. The apparatus compares the required times T1 and T2 in order to detect a leak other than the base leak hole. In this process, a specified coefficient that is defined in accordance with the base leak hole is taken into consideration. It is possible to detect the leak of the evaporation system with high accuracy even when the amount of remaining fuel is extremely large.

Abstract: A fuel vapor purge system has a canister and a pump on a purge line arranged between the canister to the intake passage. The system further has a sub-canister on a branch passage of the purge line. The pump is driven when the engine is stopped, and reduces an inside pressure of the system. The vapor discharged from the pump is adsorbed in the sub-canister, therefore, no vapor is emitted to the atmosphere. The controller checks a leak by monitoring the inside pressure after the inside pressure is reduced. It is possible to improve an accuracy of the leak detection since a leak check is executed when the engine is stopped.

Abstract: When purge control of fuel vapor, which is released from a fuel tank and is then adsorbed and retained in a fuel adsorption layer of a canister, is performed through ON/OFF control of a purge valve, ON/OFF of a heater plate received in the canister is controlled based on a purge fuel vapor concentration estimated through air-fuel ratio control operation of an engine. In this way, a sensor for measuring the purge fuel vapor concentration of the fuel vapor conducted from the canister to an intake passage of the engine can be eliminated.