Abstract: An air-fuel ratio control device for an internal combustion engine, the device comprising a unit for detecting a first fuel purge condition from the canister after the fuel tank is filled with fuel, and for reducing the amount of fuel to be supplied to the engine when the first fuel purge condition is detected.

Abstract: A device for detecting a malfunction of a fuel evaporative purge system comprises a temperature sensor for detecting a temperature inside a canister. During the absorbing and purging operations of the purge system, the device calculates changes in the temperature when absorbing and purging and compares the temperature changes with predetermined values denoting that the purge system is operating normally, and determines whether a malfunction has occurred in the purge system from the result of the comparison.

Abstract: A device for detecting a malfunction of a fuel evaporative purge system comprises a pressure sensor for detecting gas pressure in a purge passage connecting a canister to an intake pipe, and an intake vacuum sensor for detecting a negative pressure in the intake pipe. In the purging condition, the device determines whether the obtained relationship between the detected negative pressure in the purge passage and the detected intake vacuum is within a predetermined area and judges that a malfunction has occurred in the system when the relationship is not within the predetermined area.

Abstract: An air-fuel ratio control device comprising an electric air bleed control valve which controls the amount of air fed into the fuel passage of the carburetor so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio. The degree of opening of the air bleed control valve is increased as an electric current fed into the air bleed control valve is increased. Fuel vapor is fed into the intake passage from the canister. When the electric current fed into the air bleed control valve is increased and reaches a predetermined upper limit due to the supply of purge gas, the current fed into the air bleed control valve is instantaneously increased by a fixed amount.

Abstract: An air-fuel ratio control device comprising an electric air bleed control valve which controls the amount of air fed into the fuel passage of the carburetor so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio. The degree of opening of the air bleed control valve is increased as electric current fed into the air bleed control valve is increased. Fuel vapor is fed into the intake passage from the canister via a purge control valve. When the purge control valve is opened, and the rate of increase in the amount of current fed into the air bleed control valve exceeds a fixed rate, the current fed into the air bleed control valve is instantaneously increased by a fixed amount.

Abstract: An air-fuel ratio control device comprising an electric air bleed control valve which controls the amount of air fed into the fuel passage of the carburetor so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio. The degree of opening of the air bleed control valve is increased as an electric current fed into the air bleed control valve is increased. Fuel vapor is fed into the intake passage from the canister. An auxiliary air is also fed into the intake passage via an electric auxiliary air bleed control valve. When the supply of fuel vapor to the intake passage is started, if the electric current fed into the air bleed control valve increases and reaches the upper limit, the auxiliary air bleed control valve is opened. As a result, the electric current fed into the air bleed control valve is lowered and can move up and down so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio.

Abstract: In a fuel-vapor emission control system of an internal combustion engine having a purge control valve, a first start of the engine is detected after a fuel supply to the fuel tank and the time from when the engine is started is measured. Then, the amount of fuel-vapor purged from a canister filled with an adsorbent for capturing fuel-vapor is decreased for a predetermined time period. As a result, when the engine is started for the first time after the fuel supply, the amount of fuel-vapor purged is decreased to thereby improve the emission characteristic and the driveability of the vehicle.

Abstract: Device for purging evaporated fuel captured by a charcoal canister from a fuel supply system of an engine. A purge path connects the charcoal canister to an engine intake path, an ON-OFF valve and a fixed throttle are arranged in parallel in the purge path, and a solenoid valve is provided in the purge path between the engine intake path and the parallel ON-OFF valve and fixed throttle. The solenoid valve is opened only at low engine speeds and low engine temperatures. The ON-OFF valve is opened at engine loads higher than a predetermined engine load and is closed at engine loads lower than the predetermined engine load. In this way, purging of the evaporated fuel is cut off at low engine speeds and low engine temperatures, purging is occurs small quantity at low engine loads, and purging is increased at high engine loads, providing increased capturing ability of the charcoal canister without impairing drivability.

Abstract: A filler cap structure for a vehicular fuel tank particularly designed to prevent the discharge of fuel vapor to the ambient atmosphere and hence possible air pollution resulting therefrom upon filling of the fuel tank. The fuel tank has a filler tube closed by a filler cap. The filler tube is provided on its inner peripheral surface at a location inward of the bottom end of the filler cap with an annular seal seat. Defined by the annular seal seat, the inner peripheral surface of the fillter tube, and the bottom portion of the filler cap is an annular space which is connected through a communication tube with a canister. The annular space is sealed from the atmosphere by a first seal member disposed between the inner peripheral surface of the filler tube and the filler cap at a location outward of the annular space.