Abstract: A fuel evaporative emission processing system suitable for a hybrid vehicle includes a fuel vapor passage, a shut-off valve, a purge passage, a first purge control valve, and a second purge control valve. The shut-off valve selectively opens and closes the fuel vapor passage communicating between a fuel tank and a canister. The first purge control valve opens and closes the purge passage communicating between the canister and an intake air passage of an internal combustion engine. The second purge control valve selectively opens or closes the tank opening passage communicating between the purge passage on an upstream side of the first purge control valve and the fuel tank. When purging the canister, by opening the second purge control valve, the evaporative fuel inside the fuel tank is directly processed by the internal combustion engine, so that increase in the amount of adsorption in the canister can be suppressed.

Abstract: An evaporated fuel processing apparatus includes a blocking valve configured to selectively allow and shut off communication between a canister and a fuel tank, and adsorbs evaporated fuel by the canister by opening the blocking valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank, and performs a purge operation of introducing purge gas into an intake air line of an internal combustion engine with the blocking valve closed while the internal combustion engine is operating, wherein the purge gas contains a fuel component released from the canister. A diagnostic apparatus is configured to diagnose whether or not the blocking valve is abnormal, based on sensing of evaporated fuel flowing through the blocking valve while the purge operation is being performed.

Abstract: A fuel evaporative emission processing system suitable for a hybrid vehicle includes a shut-off valve, a first purge control valve and a second purge control valve. The shut-off valve is selectively opens and closes a fuel vapor passage between a fuel tank and a canister. The first purge control valve selectively opens and closes a purge passage between the canister and the intake passage of an internal combustion engine. The second purge control valve selectively opens and closes a tank opening passage between the canister and the fuel tank. When releasing a pressure for refueling, the second purge control valve with a small diameter opens prior to opening of the shut-off valve so that blow-by of gas associated with opening of the shutoff valve is prevented.

Abstract: A fuel evaporative emission processing system suitable for a hybrid vehicle includes a shut-off valve, a first purge control valve and a second purge control valve. The shut-off valve is selectively opens and closes a fuel vapor passage between a fuel tank and a canister. The first purge control valve selectively opens and closes a purge passage between the canister and the intake passage of an internal combustion engine. The second purge control valve selectively opens and closes a tank opening passage between the canister and the fuel tank. When releasing a pressure for refueling, the second purge control valve with a small diameter opens prior to opening of the shut-off valve so that blow-by of gas associated with opening of the shutoff valve is prevented.

Abstract: A fuel evaporative emission processing system suitable for a hybrid vehicle includes a fuel vapor passage, a shut-off valve, a purge passage, a first purge control valve, and a second purge control valve. The shut-off valve selectively opens and closes the fuel vapor passage communicating between a fuel tank and a canister. The first purge control valve opens and closes the purge passage communicating between the canister and an intake air passage of an internal combustion engine. The second purge control valve selectively opens or closes the tank opening passage communicating between the purge passage on an upstream side of the first purge control valve and the fuel tank. When purging the canister, by opening the second purge control valve, the evaporative fuel inside the fuel tank is directly processed by the internal combustion engine, so that increase in the amount of adsorption in the canister can be suppressed.

Abstract: An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and maintains the fuel tank in hermetic state by closing the valve while a vehicle is stationary, and adsorbs evaporated fuel by the canister by opening the valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank. A diagnostic apparatus includes: a pump connected to a canister-side region with respect to the valve, and configured to pressurize a system of the canister and the fuel tank; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus starts pressurization by the pump with the valve closed; brings the system into a pressurized state by opening the valve with a delay after the start of pressurization; and performs a leakage diagnosis based on a change in the internal pressure of the system from the pressurized state.

Abstract: An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating. A diagnostic apparatus includes: a pump for pressurizing a system including the fuel tank and the canister; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus diagnoses whether or not leakage is present, based on a change in the internal pressure of the system from a pressurized state, wherein the pressurized state is a state pressurized to a predetermined pressure for diagnosis that is higher than a tank pressure at start of diagnosis; and maintains the fuel tank in the pressurized state by closing the valve after termination of the diagnosis.

Abstract: A failure diagnosis apparatus for a fuel level sensor that detects a fuel remaining quantity within a fuel tank including at least a first tank and a second tank includes: a range deter mining unit for determining a range of a fuel remaining quantity on the basis of an output value of the fuel level sensor, the range being classified into a plurality of ranges in accordance with an output characteristic of the fuel level sensor; and a range failure diagnosis unit for carrying out failure diagnosis of the fuel level sensor for each range by comparing a fuel consumption quantity since the ranges are changed with a failure determining threshold value individually set up for each range.

Abstract: A failure diagnosis apparatus for a fuel level sensor that detects a fuel remaining quantity within a fuel tank including at least a first tank and a second tank includes: a range deter mining unit for determining a range of a fuel remaining quantity on the basis of an output value of the fuel level sensor, the range being classified into a plurality of ranges in accordance with an output characteristic of the fuel level sensor; and a range failure diagnosis unit for carrying out failure diagnosis of the fuel level sensor for each range by comparing a fuel consumption quantity since the ranges are changed with a failure determining threshold value individually set up for each range.

Abstract: An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating. A diagnostic apparatus includes: a pump for pressurizing a system including the fuel tank and the canister; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus diagnoses whether or not leakage is present, based on a change in the internal pressure of the system from a pressurized state, wherein the pressurized state is a state pressurized to a predetermined pressure for diagnosis that is higher than a tank pressure at start of diagnosis; and maintains the fuel tank in the pressurized state by closing the valve after termination of the diagnosis.

Abstract: An evaporated fuel processing apparatus includes a blocking valve configured to selectively allow and shut off communication between a canister and a fuel tank, and adsorbs evaporated fuel by the canister by opening the blocking valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank, and performs a purge operation of introducing purge gas into an intake air line of an internal combustion engine with the blocking valve closed while the internal combustion engine is operating, wherein the purge gas contains a fuel component released from the canister. A diagnostic apparatus is configured to diagnose whether or not the blocking valve is abnormal, based on sensing of evaporated fuel flowing through the blocking valve while the purge operation is being performed.

Abstract: An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and maintains the fuel tank in hermetic state by closing the valve while a vehicle is stationary, and adsorbs evaporated fuel by the canister by opening the valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank. A diagnostic apparatus includes: a pump connected to a canister-side region with respect to the valve, and configured to pressurize a system of the canister and the fuel tank; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus starts pressurization by the pump with the valve closed; brings the system into a pressurized state by opening the valve with a delay after the start of pressurization; and performs a leakage diagnosis based on a change in the internal pressure of the system from the pressurized state.

Abstract: A leak diagnostic apparatus is provided for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine. The leak diagnostic apparatus is basically provided with a pressure detecting device and a leak determining device. The pressure detecting device is configured and arranged to detect a pressure inside the evaporative emission control system, which includes the fuel tank. The leak determining device sets a leak determination threshold value in accordance with a deformation amount of the fuel tank, and determines if a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value.

Abstract: A leak diagnostic apparatus is provided for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine. The leak diagnostic apparatus is basically provided with a pressure detecting device and a leak determining device. The pressure detecting device is configured and arranged to detect a pressure inside the evaporative emission control system, which includes the fuel tank. The leak determining device sets a leak determination threshold value in accordance with a deformation amount of the fuel tank, and determines if a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value.

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 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 fuel vapor treatment apparatus includes a first canister purges fuel vapor into an intake passage of an engine through a purge passage, which communicates with a first detection passage having a throttle. A second canister is located on an opposite side of the purge passage with respect to the throttle, and communicates with the first detection passage. A gas flow generating unit generates gas flow by reducing pressure in a second detection passage communicating with the second canister. A pressure detecting unit detects pressure correlated with the throttle and the gas flow generating unit. An exhaust detecting unit detects exhaust of fuel vapor from the second canister to the second detection passage. A purge control unit controls purge of fuel vapor from the purge passage to the intake passage in accordance with detection results of the pressure detecting unit and the exhaust detecting unit.

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.