Abstract: When high-pressure purge (the first purge control) (d-f) in which fuel evaporative gas in the fuel tank is emitted until internal pressure in the fuel tank decreases to a second predetermined pressure by closing a vapor solenoid valve, opening a fuel tank shutoff valve and a purge control valve when an engine is running finishes, connecting passage purge (the second purge control) (f-g) in which the fuel evaporative gas in vapor piping and purge piping is emitted up to a second predetermined volume (a second predetermined value) or above is performed, and then the fuel evaporative gas in a canister is emitted by opening the vapor solenoid valve (the third purge control) (g-h).

Abstract: When high-pressure purge (the first purge control) (d-f) in which fuel evaporative gas in the fuel tank is emitted until internal pressure in the fuel tank decreases to a second predetermined pressure by closing a vapor solenoid valve, opening a fuel tank shutoff valve and a purge control valve when an engine is running finishes, connecting passage purge (the second purge control) (f-g) in which the fuel evaporative gas in vapor piping and purge piping is emitted up to a second predetermined volume (a second predetermined value) or above is performed, and then the fuel evaporative gas in a canister is emitted by opening the vapor solenoid valve (the third purge control) (g-h).

Abstract: A control apparatus for an engine introduces purge gas containing fuel gas evaporated from a fuel tank into an intake system includes an air-fuel ratio calculation unit that calculates an air-fuel ratio (AF) of the engine, and a purge rate calculation unit that calculates a purge rate (RPRG) corresponding to an introduction rate of the purge gas. The control apparatus further includes a concentration calculation unit that calculates a concentration (KAF_PRG) of the purge gas based on the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and the purge rate (RPRG) calculated by the purge rate calculation unit. A decision unit permits or inhibits the concentration calculation unit to calculate the concentration (KAF_PRG) based on the purge rate (RPRG) calculated by the purge rate calculation unit. The estimation accuracy of the concentration (KAF_PRG) of purge gas is improved.

Abstract: A controlling apparatus for an engine includes a purge path connected to a sealing-type fuel tank and an intake system of an engine and is configured to allow purge gas containing evaporated fuel from the fuel tank to flow therethrough. A purge valve placed in the purge path is configured to adjust a flow rate of the purge gas. A calculation unit calculates a degree of opening of the purge valve based on a target introduction ratio of the purge gas, and a controlling unit controls the purge valve so as to establish the degree of opening calculated by the calculation unit. The calculation unit corrects, in high-pressure purge performed when a pressure in the fuel tank increases exceeding a predetermined pressure, the degree of opening using a tank pressure flow velocity correction coefficient K2 corresponding to an upstream pressure of the purge valve.

Abstract: When fuel tank internal pressure is at a first predetermined pressure P1 or above over a first predetermined time length t1, a fuel tank shutoff valve is opened and a vapor solenoid valve is closed to make piping internal pressure equal to the fuel tank internal pressure. Then, a purge control valve is opened to emit fuel evaporative gas from the fuel tank into an intake passage. When the fuel tank internal pressure is continuously at a second predetermined pressure P2 or below over the first predetermined time length t1, the fuel tank shutoff valve is closed, and when accumulated volume in high-pressure purge finishing phase reaches a second predetermined volume iv2 or above, the vapor solenoid valve is opened. When the accumulated volume in high-pressure purge finishing phase reaches a first predetermined volume iv1 or above, the purge control valve is opened and the engine is stopped.

Abstract: A controlling apparatus for an engine includes a purge path connected to a sealing-type fuel tank and an intake system of an engine and is configured to allow purge gas containing evaporated fuel from the fuel tank to flow therethrough. A purge valve placed in the purge path is configured to adjust a flow rate of the purge gas. A calculation unit calculates a degree of opening of the purge valve based on a target introduction ratio of the purge gas, and a controlling unit controls the purge valve so as to establish the degree of opening calculated by the calculation unit. The calculation unit corrects, in high-pressure purge performed when a pressure in the fuel tank increases exceeding a predetermined pressure, the degree of opening using a tank pressure flow velocity correction coefficient K2 corresponding to an upstream pressure of the purge valve.

Abstract: A control apparatus for an engine introduces purge gas containing fuel gas evaporated from a fuel tank into an intake system includes an air-fuel ratio calculation unit that calculates an air-fuel ratio (AF) of the engine, and a purge rate calculation unit that calculates a purge rate (RPRG) corresponding to an introduction rate of the purge gas. The control apparatus further includes a concentration calculation unit that calculates a concentration (KAF—PRG) of the purge gas based on the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and the purge rate (RPRG) calculated by the purge rate calculation unit. A decision unit permits or inhibits the concentration calculation unit to calculate the concentration (KAF—PRG) based on the purge rate (RPRG) calculated by the purge rate calculation unit. The estimation accuracy of the concentration (KAF—PRG) of purge gas is improved.

Abstract: A PCV valve include a housing which internally has a valve chamber including an entrance at one end and an exit at the other end in an axial direction of the valve chamber. In the valve chamber, a valve element which is axially movable and a spring which urges the valve element toward the entrance are provided. An electric heater is provided in the housing. The valve element includes an end which is movable close to the entrance. The electric heater is arranged in such a manner as to surround the valve chamber from the exit to the end of the valve element closer to the entrance. The electric heater includes a cylindrical bobbin made of a high heat-conductive material and a coil wound on the outer periphery of the bobbin. The bobbin has an inner peripheral surface forming a large part of an inner peripheral surface of the valve chamber.