An evaporated fuel processing apparatus is provided with a blocking valve disposed in a vapor passage. The blocking valve has: a valve whose stroke amount is adjusted by a stepping motor; and a relief valve being opened regardless of the stroke amount when tank pressure of a fuel tank is greater than or equal to a predetermined pressure to allow communication between the fuel tank and a canister. The evaporated fuel processing apparatus is provided with a controller configured (i) to control the stepping motor to move the valve in a valve opening direction while prohibiting a valve opening position learning process when the tank pressure is greater than or equal to the predetermined pressure and (ii) to allow the valve opening position learning process when the tank pressure is less than the predetermined pressure.

A method for a fuel system is provided, wherein a fuel vapor canister is vented to an engine intake during a first condition, and wherein a restriction in a canister vent pathway is indicated, responsive to a change in a fuel tank pressure transducer output greater than a threshold. If the fuel tank pressure transducer output changes less than the threshold, degradation of the fuel tank pressure transducer is indicated. In this way, a fuel tank pressure transducer offset may be distinguished from a canister vent pathway restriction if a fuel tank pressure transducer indicates a significant pressure or vacuum in a fuel tank following a vehicle-off soak.

A vaporized fuel treatment device includes a sealing valve disposed in a vapor passage between a fuel tank and a canister and is configured to include a valve element moves forward and backward in an axial direction to a valve seat, a cut-off valve configured to cut off a communication between the canister and an atmosphere, a tank internal pressure sensor detects an internal pressure of the fuel tank, and a canister internal pressure sensor that detects an internal pressure of the canister, a controller programmed to change an axial distance between the valve element and the valve seat in a state where the cut-off valve cuts off the communication between the canister and the atmosphere and to learn a valve opening start position of the sealing valve based on changes in the internal pressures of the fuel tank and the canister depending on a change in the axial distance.

Methods and systems are provided for preheating a fuel vapor storage canister in an evaporative emissions system prior to a vehicle start. In one example, a method may include learning common vehicle routes and identifying routes in which fuel vapor storage canister preheating is indicated, such as routes that will enable fuel vapors to be purged to an engine intake shortly after the vehicle start. Then, in anticipation of an identified route for fuel vapor storage canister preheating, a vehicle controller may be transitioned from a sleep mode to an awake mode prior to the vehicle start in order to commence a fuel vapor storage canister preheating routine.

Methods and systems are provided for determining barometric pressure. In one example, an onboard vacuum pump is utilized to draw a vacuum at a constant flow rate across a reference orifice, and the resulting vacuum level is converted to a barometric pressure. In this way, other sensors for determining barometric pressure in a vehicle may be rationalized without the use of engine operation, and in an example where the other sensors for determining barometric pressure are not functioning as desired, barometric pressure as inferred from the onboard pump may be utilized to adjust engine operation.

The present invention provides improved auxiliary fuel tank control systems and methods that avoid the need for locating, identifying, and tapping into a wire leading from the sending unit of the vehicle's primary fuel tank by connecting directly to a diagnostic port of the vehicle which is in communication with the output from the sending unit. Based on information received from the sending unit, embodiments of the invention may automatically cause fuel to be pumped from an auxiliary tank to the primary tank when the amount of fuel in the primary tank drops below a threshold.

A purge device includes a canister; a purge passage configured to extend from the canister and be connected to an upstream side of a compressor of a supercharger in an intake passage; a supply unit configured to supply purge gas to the upstream side of the compressor in the intake passage during supercharging; a throttle configured to be provided in a portion of the intake passage connected with the purge passage and limit an inflow of gas from the purge passage; a sensor configured to detect internal pressure downstream of the supply unit in the purge passage; and a control device configured to determine that a passage end of the purge passage deviates from the intake passage, in a case where a detection value obtained by the sensor during the operation of the supply unit is lower than a predetermined pressure.

Methods and arrangements for transitioning an engine between a deceleration cylinder cutoff (DCCO) state and an operational state are described. In one aspect, transitions from DCCO begin with reactivating cylinders to pump air to reduce the pressure in the intake manifold prior to firing any cylinders. In another aspect, transitions from DCCO, involve the use of an air pumping skip fire operational mode. After the manifold pressure has been reduced, the engine may transition to either a cylinder deactivation skip fire operational mode or other appropriate operational mode. In yet another aspect a method of transitioning into DCCO using a skip fire approach is described. In this aspect, the fraction of the working cycles that are fired is gradually reduced to a threshold firing fraction. All of the working chambers are then deactivated after reaching the threshold firing fraction.

A fault detection unit of an internal combustion engine includes a recirculation pipe connected with an upstream-side part of an intake pipe of the internal combustion engine upstream of a supercharger, the recirculation pipe to supply an evaporated fuel that is unburned and is generated in the internal combustion engine to the intake pipe, and a fault detection unit to detect a leakage occurrence of the recirculation pipe based on a crank-case inner pressure of the internal combustion engine when the internal combustion engine is operating in a specified operation condition that the crank-case inner pressure is a positive pressure.

An evaporative emissions control system for an internal combustion engine having an air intake manifold is provided. The system includes a carbon canister configured to receive fuel vapor, a purge valve fluidly coupled to the carbon canister, an air induction system configured to fluidly couple to the air intake manifold, a conduit fluidly coupled between the purge valve and the air induction system, and an inlet valve disposed in the air induction system. The inlet valve is configured to selectively move between an open position and a closed position to vary an air restriction in the air induction system and generate a vacuum. The vacuum draws fuel vapor from the carbon canister through the conduit into the air induction system.