Fuel evaporative emission processing system
AssigneeNissan Motor Co., Ltd.
InventorShinsuke Takakura
Life of this patent
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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.
Claims20
A fuel evaporative emission processing system for an internal combustion engine, comprising:
- a fuel vapor passage communicating a fuel tank and a charge port of a canister;
- a shut-off valve interposed in the fuel vapor passage and configured to selectively open and close the fuel vapor passage, the shut-off valve being a solenoid valve that is configured to open during refueling;
- a tank opening passage communicating the fuel tank and the canister;
- a second control valve interposed in the tank opening passage and configured to open prior to opening of the shut-off valve when releasing a pressure for refueling;
- a tank pressure sensor configured to detect a pressure in the fuel tank;
- and
- a diagnosis mechanism configured to diagnose the second control valve based on a pressure change in the fuel tank developed after opening of the second control valve from a state in which the pressure in the fuel tank is positive with the shut-off valve and the second control valve closed.
Dependencies are inferred from the claim text.