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: A fuel vapor handling apparatus supplies a purging air to a canister by using a purge pump and purges fuel desorbed from the canister into an intake pipe. A controller intermittently operates the purge so that the canister internal temperature recovers from a reduced level caused by the latent heat of vaporization of fuel during an operating period of the purge pump. Therefore, desorption of fuel from the canister during an operating period is facilitated. Since the actual operating time of the purge pump is reduced, the life of a motor that is a power unit of the purge pump becomes longer.

Abstract: A fuel adsorption layer formed in a canister is partitioned into an upper adsorption layer and a lower adsorption layer by a partition plate in which a heater is embedded. The relation between a heating value of the heater and thickness X of the upper and lower adsorption layers is set so that the temperature of a part closest to the heater heating face of the fuel adsorption layer is lower than a fire point of the fuel, and the temperature of a part farthest from the heater heating face is higher than the boiling point of the fuel. With the configuration, by heating the fuel adsorption layer by the heater, the desorption performance of activated carbon is improved, and almost all of the fuel vapors adsorbed can be desorbed.

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: 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: A shut valve is provided in an intake line farther upstream than a throttle valve of the intake line and farther downstream than an air cleaner. This shut valve is opened by a signal or the like from an ECU when an engine is operating. Further, the shut valve closes when the engine is stopped so as to suppress evaporative fuel inside the intake line from flowing outside through the air cleaner. The evaporative fuel trapped inside the intake line passes through a bypass passage that provides communication between the intake line and the canister, and is then adsorbed with an adsorbent in the canister. A blow-by line is also connected to the intake line that is closed off by the shut valve. Because the blow-by line is closed off by a blow-by valve, which is closed during normal operation, when the engine is stopped, sticking of the shut valve and the throttle valve and the like due to the inflow of blow-by gas into the intake line is inhibited.

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: A fuel vapor handling apparatus supplies a purging air to a canister by using a purge pump and purges fuel desorbed from the canister into an intake pipe. A controller intermittently operates the purge so that the canister internal temperature recovers from a reduced level caused by the latent heat of vaporization of fuel during an operating period of the purge pump. Therefore, desorption of fuel from the canister during an operating period is facilitated. Since the actual operating time of the purge pump is reduced, the life of a motor that is a power unit of the purge pump becomes longer.

Abstract: A fuel adsorption layer formed in a canister is partitioned into an upper adsorption layer and a lower adsorption layer by a partition plate in which a heater is embedded. The relation between a heating value of the heater and thickness X of the upper and lower adsorption layers is set so that the temperature of a part closest to the heater heating face of the fuel adsorption layer is lower than a fire point of the fuel, and the temperature of a part farthest from the heater heating face is higher than the boiling point of the fuel. With the configuration, by heating the fuel adsorption layer by the heater, the desorption performance of activated carbon is improved, and almost all of the fuel vapors adsorbed can be desorbed. As a result, the fuel vapors do not remain in the canister, so that all of the fuel vapors which flow in at the time of adsorption can be adsorbed with reliability.

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: 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: A canister for use in an evaporative emission control system of an automotive vehicle is provided which includes a box-like casing, an inlet port formed in one end wall of the casing through which fuel vapors generated within a fuel tank are drawn into the canister, and a plurality of vapor-adsorbing passages each of which is filled with activated carbon and has a given length through which the fuel vapors drawn through the inlet port flow. The vapor-adsorbing passages are all arranged within said casing in parallel to each other. This arrangement allows the casing to be of a flat shape which facilitates easy installation of the canister within a flat space around a fuel tank.

Abstract: An antidiffusion layer is provided between a first fuel adsorption layer communicated with a fuel tank and a second fuel adsorption layer communicated with air. Since adsorbing ability of the antidiffusion layer is lower than that of the first and second fuel adsorption layers, pore diffusion of the fuel vapor from the first fuel adsorption layer to the second fuel adsorption layer is reduced. Since the antidiffusion layer forms a plurality of nonlinear passages, air diffusion of the fuel vapor is reduced. Therefore, the diffusion of the fuel vapor is suppressed with a thin, small and simple antidiffusion layer, and the canister can be simplified and the reduction of the number of parts and the cost thereof can be realized.

Abstract: An evaporative emission control system which may be used in automotive vehicles is disclosed. The evaporative emission control system includes a canister, an inlet passage, a fuel vapor passage, an outlet valve, and an inlet valve. The air inlet passage is exposed at an end to the atmosphere and connected at the other end to the canister for drawing fresh air into the canister. The fuel vapor passage communicates between the canister and a fuel tank. When a pressure in the fuel tank is increased above a given level so that a difference in internal pressure between the fuel tank and the canister reaches a first value, the outlet valve establishes communication between the fuel tank and the canister to allow fuel vapor evaporated within the fuel tank to be drawn into the canister through the fuel vapor passage.

Abstract: A parallel-plate type gas plasma etching apparatus for etching a workpiece having a multilayer structure having a high etch rate ratio. A pair of parallel-plate electrodes are disposed in a reactor. A workpiece to be etched is disposed upon one of the electrodes. The reactor is held at a predetermined pressure and an etching gas supplied thereto. Rf power is applied between the electrodes with the positive terminal of the rf generator being coupled to the electrode upon which the workpiece is disposed. The frequency of the rf power is 10 MHz or less.

Abstract: A parallel-plate type gas plasma etching apparatus for etching a workpiece having a multilayer structure having a high etch rate ratio. A pair of parallel-plate electrodes are disposed in a reactor. A workpiece to be etched is disposed upon one of the electrodes. The reactor is held at a predetermined pressure and an etching gas supplied thereto. Rf power is applied between the electrodes with the positive terminal of the rf generator being coupled to the electrode upon which the workpiece is disposed. The frequency of the rf power is 10 MHz or less.