The present disclosure relates to internal combustion engines and its teachings may be applied to methods for leakage diagnosis in a fuel tank system. A method for diagnosing leakage may include: closing a fresh air line and a hydrocarbon/air mixture line connected to the fuel tank; measuring a first pressure change in the fuel tank system over a predefined first time interval; opening the fresh air line; operating the purge air pump until a predefined excess pressure is reached; closing the fresh air line; measuring a second pressure change over a predefined second time interval; and comparing the pressure changes to diagnose a leakage in the fuel tank system.

An engine apparatus includes an engine, a supercharger, an evaporated fuel treatment device, a controller and the engine apparatus is configured to determine a purge classification whether the evaporated fuel is a first purge in which the evaporated fuel flows dominantly in a first purge passage or a second purge in which the evaporated fuel flows dominantly in a second purge passage based on a relative ejector pressure that is a pressure of a suction port of the ejector and a value obtained by adding an offset amount based on a cross-sectional area of the second purge passage with respect to a cross-sectional area of the first purge passage to a pressure behind a throttle valve that is the pressure on a downstream side of the throttle valve of the intake pipe.

An evaporative emissions control system for an internal combustion engine having a plurality of cylinders including a dedicated exhaust gas recirculation (DEGR) cylinder. The evaporative emissions control system including a fuel tank vent line configured to direct fuel vapors evaporated from fuel within a fuel tank to only the DEGR cylinder of the plurality of cylinders. A purge valve is along the fuel vent line and is configured to control passage of fuel vapors to the DEGR cylinder.

Methods and systems are provided for controlling the purging of a fuel vapor canister coupled to a vehicle fuel tank, configured for capturing and storing vapors emanating from the tank. In one example, two canister purge valves are coupled in series in a fuel vapor conduit between the fuel vapor canister and engine intake, one at the intake manifold and one at the fuel vapor canister, such that fine control over the introduction of fuel vapors into the engine is maintained via the purge valve at the intake manifold, while thorough purging of the fuel vapor canister may be regulated via the purge valve at the fuel vapor canister. In this way, fuel vapors in the fuel vapor canister may be effectively purged to intake, thus reducing the potential for undesired evaporative emissions.

Methods and systems are provided for managing fuel vapor in a vehicle evaporative emissions system configured with a fuel vapor canister for capturing and storing vapors from a vehicle fuel tank. In one example, a three-way valve is positioned between the fuel vapor canister and atmosphere, and may function during engine-off conditions to direct fuel tank vapors through the fuel vapor canister where they may be adsorbed, and then to an intake manifold of the engine where a second adsorbent for capturing and storing fuel vapors is positioned. In this way, fuel vapors that are not adsorbed by the fuel vapor canister, or fuel vapors that are freed from the canister during engine-off conditions may be routed to the second adsorbent prior to exiting to atmosphere, thus reducing undesired bleed emissions.

In an evaporation fuel processing apparatus, a canister holds an evaporation fuel evaporated in a fuel tank, a purge passage communicates with the canister and an intake passage of an engine, a purge pump disposed in the purge passage pressurizes and feeds an air in the canister toward the intake passage, a bypass passage disposed in the purge passage bypasses the purge pump, and an on-off valve disposed in the purge passage opens and closes the bypass passage. When an intake negative pressure of the intake passage is low, the purge pump is activated, and the bypass passage is closed by the on-off valve. When the intake negative pressure of the intake passage is not low, the purge pump is stopped, and the bypass passage is open by the on-off valve.

A vaporized fuel processing apparatus for an engine, which includes an intake passage equipped with a supercharging device and a throttle valve, has an adsorbent canister and a purge passage. The adsorbent canister is adapted to communicate with a fuel tank. The purge passage communicates the adsorbent canister with the intake passage of the engine. The purge passage has in series a purge valve for controlling communication through the purge passage and a purge pump for generating gas flow from the adsorbent canister toward the intake passage. The purge passage includes a sub-passage for communicating the adsorbent canister with the intake passage without passing through the purge pump. The purge passage divides into a first passage connected to the intake passage downstream of the throttle valve and a second passage connected to the intake passage upstream of the supercharging device.

In a control apparatus for an internal combustion engine, a vapor concentration learned value learned as a concentration of fuel in purge gas is reflected in an injection amount command value used for fuel injection amount control. An electronic control unit changes a reflection mode of reflecting the vapor concentration learned value in the injection amount command value depending on a pattern of switching an inlet through which the purge gas flows into an intake passage, between a first inlet and a second inlet upstream of the first inlet, and executes the reflection in the changed reflection mode during a period from a start of an intake of intermediate gas into a cylinder to completion of the intake of the intermediate gas. The intermediate gas is present in a portion of the intake passage between the first inlet and the second inlet when switching of the inlet is performed.

A valve assembly includes a seat separating a cavity of a valve body into a first cavity portion and a second cavity portion. The assembly includes a cover device separating the first cavity portion into a first pocket and a second pocket. The cover device defines at least one hole to provide fluid communication between an aperture of the seat and an outlet of the valve body via the hole. The cover device is movable between a rest position to restrict fluid communication between the aperture and the hole, and an actuated position to increase fluid communication between the aperture and the hole when a vacuum is created in the first cavity portion. The aperture is in direct fluid communication with the first pocket when in the actuated position. The outlet is in direct fluid communication with the second pocket when in the rest and actuated positions.

The disclosure relates to a method for ascertaining the flow through a timer valve. The method includes detecting the pressure upstream of the timer valve during an evacuation of a container arranged upstream of the timer valve, ascertaining the flow through the timer valve based on the detected pressure upstream of the timer valve and based on the temperature and the volume of the gas in the container. The method also includes comparing the flow ascertained during the evacuation and a modeled flow and/or comparing a variable dependent on the ascertained flow and a variable dependent on the modeled flow. Additionally, the method includes adapting the model in the event of a discrepancy between the flow ascertained during the evacuation and the modeled flow and/or in the event of a discrepancy between the variable dependent on the ascertained flow and the variable dependent on the modeled flow.