Abstract: A fuel vapor treatment system which has adsorbent, a purge passage for introducing a mixture gas of air and the fuel vapor desorbed from the adsorbent into the internal combustion engine, a detection passage which communicates to the purge passage, and a pump which generates gas flow so that the mixture gas flows into the detection passage from the purge passage. A pressure sensor detects fuel vapor concentration. An ECU and a purge control valve controls a purge of the mixture gas from the purge passage to the internal combustion engine based on a reference concentration of the fuel vapor. The ECU establishes the detection interval of the fuel vapor concentration in consideration of change in reference concentration.

Abstract: An ECU computes a transit time from a time when the fuel vapor passes the purge valve right after the purge valve is opened until a time when the fuel vapor reaches a vicinity of the fuel injector. Further more, the ECU computes a fuel vapor concentration at the vicinity of the fuel injector after the transit time has elapsed based on a first-order lag curve which is defined by a maximum variation of the fuel vapor concentration and a time constant. Correcting the fuel injection quantity according to the fuel vapor concentration at the vicinity of the injector restricts a disturbance of air-fuel ratio at a time of starting purge process.

Abstract: A fuel property detection device for detecting a property of fuel based on a detection signal output from a photoreceptor includes a light guiding member having a reflecting surface located in direct contact with the fuel. The light guiding member includes a light emitting surface through which measurement light from a light source is emitted from the light guiding member into the fuel, a light incident surface through which the measurement light emitted from the light emitting surface and passing through the fuel enters again the light guiding member, and the reflecting surface from which the measurement light incident from the light incident surface is reflected toward the photoreceptor. The light incident surface and the light emitting surface are opposite to each other to have a space therebetween in the light guiding member, and the space is provided to be filled with the fuel.

Abstract: A fuel vapor treatment apparatus includes: a detection passage provided with a restrictor therein; a pump generating a gas-flow in the detection passage; and a differential pressure sensor detecting a pressure loss at the restrictor. A fuel vapor concentration is computed based on a pressure loss when air passes through the detection passage and a pressure loss when an air-fuel mixture passes through the detection passage. When the computed fuel vapor concentration reaches a specified value, an internal combustion engine is started and the fuel vapor treatment apparatus starts to supply the fuel vapor adsorbed by the canister to the internal combustion engine.

Abstract: A leak detecting apparatus includes a canister adsorbing a fuel vapor evaporated in a fuel tank, a measure passage, a pump connected with the canister through the measure passage, and a pressure senor detecting a pressure in the measure passage. The pump depressurizes the measure passage, the canister, and the fuel tank so that a leakage of the fuel vapor is detected. When a blow-by of the fuel vapor is arisen, the pump is stopped to forcibly terminate a depressurization.

Abstract: A rotation angle detection device for detecting a rotation angle of an object has a substantially cylinder-shaped yoke, a magnetism generation unit which is fixed to an inner surface of the yoke, a magnetism detection member which is arranged substantially in a center axis of the yoke, at least one bearing which rotatably supports the yoke, and a support member which holds the bearing. The yoke is made of a magnetic metal, and fixedly mounted at the object to be rotatable integrally with the object. The magnetism generation unit generates a magnetic field substantially perpendicular to the center axis of the yoke. The magnetism detection member generates an output corresponding to a variation of the magnetic field to detect the rotation angle of the object relative to the magnetism detection member.

Abstract: A fuel property detection device for detecting a property of fuel based on a detection signal output from a photoreceptor includes a light guiding member having a reflecting surface located in direct contact with the fuel. The light guiding member includes a light emitting surface through which measurement light from a light source is emitted from the light guiding member into the fuel, a light incident surface through which the measurement light emitted from the light emitting surface and passing through the fuel enters again the light guiding member, and the reflecting surface from which the measurement light incident from the light incident surface is reflected toward the photoreceptor. The light incident surface and the light emitting surface are opposite to each other to have a space therebetween in the light guiding member, and the space is provided to be filled with the fuel.

Abstract: A detector for detecting evaporated fuel leakage from a fuel tank is connected to the fuel tank through a canister for absorbing evaporated fuel. When an engine is not in operation, air in the fuel tank is sucked by a pump installed in the detector. If the pressure in the fuel tank decreases to a predetermined level, it is determined that the evaporated fuel leakage is within a permissible range. An orifice passage, formed in the detector, connecting a tank passage to a sensor passage communicating with a sensor chamber where a pressure sensor is disposed is slanted relative to the tank passage to shorten the passage distance up to the pressure sensor. Further, the orifice passage is connected to the sensor passage at an obtuse angle to reduce a pressure loss in the passages. Thus, the leakage of the evaporated fuel is surely detected while making the detector compact.

Abstract: An ECU computes a transit time from a time when the fuel vapor passes the purge valve right after the purge valve is opened until a time when the fuel vapor reaches a vicinity of the fuel injector. Further more, the ECU computes a fuel vapor concentration at the vicinity of the fuel injector after the transit time has elapsed based on a first-order lag curve which is defined by a maximum variation of the fuel vapor concentration and a time constant. Correcting the fuel injection quantity according to the fuel vapor concentration at the vicinity of the injector restricts a disturbance of air-fuel ratio at a time of starting purge process.

Abstract: A leak detecting apparatus includes a canister adsorbing a fuel vapor evaporated in a fuel tank, a measure passage, a pump connected with the canister through the measure passage, and a pressure senor detecting a pressure in the measure passage. The pump depressurizes the measure passage, the canister, and the fuel tank so that a leakage of the fuel vapor is detected. When a blow-by of the fuel vapor is arisen, the pump is stopped to forcibly terminate a depressurization.

Abstract: A fuel vapor treatment system which has adsorbent, a purge passage for introducing a mixture gas of air and the fuel vapor desorbed from the adsorbent into the internal combustion engine, a detection passage which communicates to the purge passage, and a pump which generates gas flow so that the mixture gas flows into the detection passage from the purge passage. A pressure sensor detects fuel vapor concentration. An ECU and a purge control valve controls a purge of the mixture gas from the purge passage to the internal combustion engine based on a reference concentration of the fuel vapor. The ECU establishes the detection interval of the fuel vapor concentration in consideration of change in reference concentration.

Abstract: An evaporative fuel treatment apparatus is disclosed that includes a fuel tank and a purge passage that fluidly couples the intake path of an internal combustion engine and the fuel tank. The apparatus also includes a purge valve that is installed in the purge passage and controls the quantity of evaporative fuel purged from the fuel tank into the intake path. Furthermore, the apparatus includes an evaporative fuel status measuring device that measures a density-based status of evaporative fuel in the fuel tank. Additionally, the apparatus includes a purge valve controlling device that controls the purge valve based on the density-based status of the evaporative fuel measured by the evaporative fuel status measuring device.

Abstract: An evaporative fuel treatment system is disclosed that includes a canister, a detection passage having a reduced area portion, and switching device that switches fluid communication. Also included is a depressurizing device for depressurizing the detection passage coupled to the detection passage on a side of the reduced area portion opposite to the switching device, and a pressure detecting device. Moreover, the system includes an evaporative fuel state calculating device for calculating an evaporative fuel state in the mixture based on a cutoff pressure, an air pressure, and a mixture pressure of a mixture of air and the evaporative fuel. In one embodiment, the cutoff pressure, the air pressure, and the mixture pressure are detected independently and discontinuously. In another embodiment, the cutoff pressure and the air pressure are detected on a continual basis during purge of the evaporative fuel.

Abstract: A fuel vapor treatment system includes a canister containing an adsorbent, a detector detecting a concentration of a fuel vapor, a purge passage for introducing the mixture gas into an engine, and an ECU which controls a purge based on a detected fuel vapor condition quantity and learns a fuel vapor concentration. If a difference between a learned concentration and a detection concentration is not less than a specified value, the ECU performs a purge control based on the learned concentration prior to a purge control based on the detection concentration.

Abstract: A fuel vapor treatment system includes a canister containing an adsorbent, a detector detecting a concentration of a fuel vapor, a purge passage for introducing the mixture gas into an engine, and an ECU which controls a purge based on a detected fuel vapor condition quantity and learns a fuel vapor concentration. If a difference between a learned concentration and a detection concentration is not less than a specified value, the ECU performs a purge control based on the learned concentration prior to a purge control based on the detection concentration.

Abstract: A fuel vapor treatment apparatus connects with a fuel tank, which produces fuel vapor to be purged into an intake passage of an internal combustion engine through a purge passage. The fuel vapor treatment apparatus includes a state measuring unit that includes a measurement passage provided separately from the purge passage. When the measurement passage is blocked from the intake passage, the state measuring unit measures a state of fuel vapor by detecting a physical quantity of the fuel vapor in the measurement passage. The physical quantity is correlative to the state of fuel vapor. The fuel vapor treatment apparatus further includes a diagnosis unit for diagnosing a malfunction of at least one of components of the state measuring unit.

Abstract: A CPU measures an actual air-fuel ratio based on the signals detected by the air-fuel ratio sensor. When the difference between the actual air-fuel ratio and a target air-fuel ratio is larger than a predetermined value, the computer determines that a fuel vapor amount purged into the intake passage deviates from a target value due to an incorrectness of a reference flow quantity of the purge valve. The computer calculates an actual reference flow quantity based on a measured actual air-fuel ratio, and rewrites the reference flow quantity corresponding to a current intake pressure into the calculated the reference flow quantity. Thereby, the difference between the actual air-fuel ratio and the target air-fuel ratio can be reduced.

Abstract: An evaporated fuel leak detector detects leakage of an evaporated fuel generated in a fuel tank. The detector includes: a differential pressure valve, a pump for sucking a detection port side to reduce pressure on a fuel tank side, and pressure detection means for detecting pressure on a detection port side. The valve includes a detection port connecting to a fuel tank side, an atmosphere port opened to atmosphere, a pressure chamber and a valve member displaceable in accordance with differential pressure between the detection port and the pressure chamber for connecting and disconnecting a connection between the detection port and the atmosphere port. The valve member disconnects between the detection port and the atmosphere port in a case where pressure of the pressure chamber becomes larger than pressure of the detection port by a predetermined pressure.

Abstract: A leakage detecting device is connected to an evaporating fuel processing apparatus to detect leakage of evaporating fuel in a ventilation apparatus that includes an electric pump, a fuel tank, and a filter. The electric pump includes a pump portion and a motor portion. The pump portion is capable of generating at least one of pressurizing force and de-pressurizing force. The motor portion drives the pump portion. The filter absorbs fuel evaporating in the fuel tank. The leakage detecting device generates pressure difference between the inside of the ventilation apparatus and the outside of the ventilation apparatus in accordance with the pressurizing force and the de-pressurizing force generated using the electric pump to detect a leakage condition of the ventilation apparatus. The leakage detecting device includes a rotation speed controlling means that controls rotation speed of the motor portion at a predetermined rotation speed.

Abstract: A fuel vapor treatment apparatus includes a first canister, a purge passage, an atmosphere passage, a first detection passage provided with a restrictor, and a passage-changing valve for changing the connection passage of the first detection passage between the purge passage and the atmosphere passage. The apparatus further includes a second canister connecting with the first detection passage on the opposite side of the passage-changing valve across the restrictor. A differential pressure sensor detects a pressure difference between both ends of the restrictor. An ECU computes the concentration of fuel vapor on the basis of the detection result of the differential pressure sensor.