Evaporative emission control system
AssigneeToyota Jidosha Kabushiki Kaisha
InventorAkinori Osanai
Life of this patent
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Abstract
An evaporative emission control system detects an opening failure of a purge control valve that controls the amount of purge gas flowing from a canister into an intake passage of the engine, and determines whether a significant shift occurs in an air/fuel ratio feedback factor when the opening failure is detected. If the air/fuel ratio feedback factor is shifted to the rich side, a rich-side initial value is set to a vapor concentration learned value, and, if the feedback factor is shifted to the lean side, a lean-side initial value is set to the vapor concentration learned value. These initial values give larger changes to the vapor concentration learned value than update amounts by which the learned value is updated during normal learning control.
Claims30
An evaporative emission control system including a canister for collecting fuel vapor flowing from a fuel tank, comprising:
- a purge control valve that controls a degree of fluid communication between the canister and an intake passage of an internal combustion engine;
- an air/fuel ratio deviation detecting unit that detects a deviation of an air/fuel ratio from a predetermined range under a situation where purge gas is supplied to the intake passage;
- a fuel injection amount calculating unit that calculates a fuel injection amount according to an expression including a correction factor for canceling an influence of the purge gas;
- a correction factor updating unit that updates the correction factor so as to reduce the deviation of the air/fuel ratio;
- an opening failure detecting unit that detects an opening failure of the purge control valve, the opening failure occurring when the purge control valve is stuck in an open state;
- a deviating condition determining unit that determines the presence and direction of the deviation of the air/fuel ratio when the opening failure is detected;
- and
- an initial value setting unit that assigns a rich-side initial value or a lean-side initial value to the correction factor depending upon the direction of the deviation of the air/fuel ratio when the deviating condition determining unit determines the presence of the deviation of the air/fuel ratio, wherein
- a difference between a reference value of the correction factor and the rich-side initial value and a difference between the reference value and the lean-side initial value are both larger than an update amount of the correction factor by which the correction factor is updated at a time by the correction factor updating unit.
An evaporative emission control system including a canister for collecting fuel vapor flowing from a fuel tank, comprising:
- a purge control valve that controls a degree of fluid communication between the canister and an intake passage of an internal combustion engine;
- a fuel cut control unit that executes fuel cut control for stopping fuel injection into the engine when predetermined fuel cut conditions are satisfied;
- an opening failure detecting unit that detects an opening failure of the purge control valve, the opening failure occurring when the purge control valve is stuck in an open state;
- and
- a fuel cut restricting unit that restricts execution of the fuel cut control when the opening failure is detected.
An evaporative emission control system including a canister for collecting fuel vapor flowing from a fuel tank, comprising:
- a purge control valve that controls a degree of fluid communication between the canister and an intake passage of an internal combustion engine;
- a cold-start correcting unit that performs correction for increasing a fuel injection amount during a cold start of the engine;
- an opening failure detecting unit that detects an opening failure of the purge control valve, the opening failure occurring when the purge control valve is stuck in an open state;
- and
- a correction amount reducing unit that reduces an amount by which the fuel injection amount is increased by the cold-start correcting unit when the opening failure is detected.
An evaporative emission control system including a canister for collecting fuel vapor flowing from a fuel tank, comprising:
- a purge control valve that controls a degree of fluid communication between the canister and an intake passage of an internal combustion engine;
- an idle air flow controller that allows a desired amount of idle air to flow during idling of the engine;
- an opening failure detecting unit that detects an opening failure of the purge control valve, the opening failure occurring when the purge control valve is stuck in an open state;
- and
- an idle air amount increasing unit that increases the amount of idle air when the opening failure is detected.
An evaporative emission control system including a canister for collecting fuel vapor flowing from a fuel tank, wherein the canister has a vapor port that communicates with the fuel tank, a purge port that communicates with an intake passage of an internal combustion engine, and an atmospheric vent located opposite to the vapor port and the purge port with an inside space of the canister interposed therebetween, comprising:
- a purge control valve that controls a degree of fluid communication between the purge port and the intake passage;
- a canister check valve that opens and closes the atmospheric vent;
- an opening failure detecting unit that detects an opening failure of the purge control valve, the opening failure occurring when the purge control valve is stuck in an open state;
- and
- an atmospheric vent closing unit that places the canister check valve in a closed state so as to close the atmospheric vent when the opening failure is detected.
Dependencies are inferred from the claim text.