A method may verify that a fuel tank cap is present and properly closed after refueling of a motor vehicle fuel tank. The method may include, in response to a request for refueling: (a1) enabling refueling of the motor vehicle fuel tank by opening a first vent valve connected in series in a vent line, downstream from a first port of a recirculation line coupled to the vent line, so that to vent the motor vehicle fuel tank to the atmosphere through a fuel vapor canister; (b1) disabling refueling of the motor vehicle fuel tank by closing the first vent valve; (c1) monitoring the internal pressure within the motor vehicle fuel tank when the refueling request is finished; and (d1) concluding that the fuel tank cap is deemed present and properly closed when the internal pressure increases and/or remains higher than the atmospheric pressure.

Methods and systems are provided for conducting diagnostics to indicate whether a fuel system and/or an evaporative emissions system of a vehicle has a source of undesired evaporative emissions, or not. A method comprises conducting such a diagnostic via evacuating the fuel system to a target vacuum, then sealing the fuel system from atmosphere and monitoring a pressure bleed-up in the fuel system, and dynamically adjusting a pressure bleed-up threshold responsive to one or more conditions that impact the pressure bleed-up during the diagnostic, and indicating undesired evaporative emissions responsive to the pressure bleed-up reaching the adjusted pressure bleed-up threshold. In this way, interpretation of the results of such a diagnostic may be more robust, completion rates may improve, and engine operation may be improved.

A device for discharging fuel vapor from a fuel supply system for an internal combustion engine has a container which is situated in the fuel supply system and contains liquid fuel under an upwardly limited pressure. A discharge line, which leads to a tank venting system, leads out of the container. The device also has a detector for detecting vaporous fuel in the container and a blocking device which is coupled to the detector and with which the discharge line can be opened or blocked depending on the detection. A method for discharging fuel vapor from a fuel supply system for an internal combustion engine continuously detects whether vaporous fuel is also present in the container which is situated in the fuel supply system and contains the liquid fuel under an upwardly limited pressure; opens the discharge line if the vaporous fuel has been detected and blocks the discharge line if no vaporous fuel has been detected; and discharges the vaporous fuel through the opened discharge line while retaining the liquid fuel.

A leakage detector for fuel vapor treatment device is configured to diagnose a leakage of a fuel vapor in a vapor path based on an internal pressure change of the vapor path with the vapor path functioning as a closed space. The leakage detector performs the leakage diagnosis of the vapor path by correcting the effect of the pressure of the fuel vapor with regards to the internal pressure change. The leakage detector comprises a vaporization promoting device and is configured to determine whether the fuel vapor in the gas space of a fuel pump has reached a saturated state.

A fuel tank isolation solenoid valve for a vehicle is provided. The fuel tank isolation solenoid valve may include a first plunger configured to be vertically movable and a second plunger configured to move along a plunger rotation path such that the plunger is mechanically maintained in an opened position or a closed position while no power is applied to a coil.

Occlusion diagnosis of a vent passage is executed with high accuracy based on an estimated value of the volume of a sealed space. An occlusion diagnosis device includes a diagnosis unit for the diagnosis. An occlusion diagnosis unit of the diagnosis unit executes the occlusion diagnosis, based on whether or not an estimated volume of a sealed space of a fuel-vapor sealing system exceeds a volume threshold. The occlusion diagnosis determines that the vent passage is suspected of being occluded if the estimated volume is equal to or less than the volume threshold, while diagnoses that the vent passage is not occluded if the estimated volume exceeds the volume threshold. If it is determined that the vent passage is suspected of being occluded, the occlusion diagnosis unit causes the occlusion diagnosis of the vent passage to remain incomplete until a cumulative exhaust amount of fluid exceeds an exhaust amount threshold.

The present invention relates generally to a tank overfill protection system (10) designed to be installed in a tank (12). The tank overfill protection system (10) comprises a tank level sensor (14) operatively coupled to a flow control valve assembly (16). The flow control valve assembly (16) is connected to the level sensor (14) via a pilot line (18) which contains a bleed fluid for controlling closure of the flow control valve assembly (16). The tank level sensor (14) comprises a valve body (20), a pilot valve (22) mounted to the valve body (20), and a pilot valve actuator (24) operatively coupled to the pilot valve (22) for its opening and closure. The pilot valve actuator (24) includes a balance member (26) arranged to cooperate with actuator biasing means in the form of a pilot compression spring (28). The balance member (26) is in the form of a counterbalance and has a specific gravity relative to liquid or fuel within the tank (12) so that at least part submersion of the balance member (26) under the influence of the pilot compression spring (28) provides movement of the balance member (26) and closure of the pilot valve (22). This closure of the pilot valve (22) substantially closes and subsequently pressurises the bleed fluid in the pilot line (18) for closure of the flow control valve assembly (16).

A device for discharging fuel vapor from a fuel supply system for an internal combustion engine has a container which is situated in the fuel supply system and contains liquid fuel under an upwardly limited pressure. A discharge line, which leads to a tank venting system, leads out of the container. The device also has a detector for detecting vaporous fuel in the container and a blocking device which is coupled to the detector and with which the discharge line can be opened or blocked depending on the detection. A method for discharging fuel vapor from a fuel supply system for an internal combustion engine continuously detects whether vaporous fuel is also present in the container which is situated in the fuel supply system and contains the liquid fuel under an upwardly limited pressure; opens the discharge line if the vaporous fuel has been detected and blocks the discharge line if no vaporous fuel has been detected; and discharges the vaporous fuel through the opened discharge line while retaining the liquid fuel.

The present invention is directed broadly to a tank overfill protection system (10) generally comprising a flow control valve (12) operatively coupled to a tank level sensor via a pilot line (16). The flow control valve (12) generally comprises: 1. a valve body (26) defining a fluid passageway (28) between a fluid inlet (30) and a fluid outlet (32); 2. a piston (34) slidably mounted within the fluid passageway (28) and arranged for displacement for opening and closure of the fluid outlet (32); 3. a bleed fluid cavity (36) located within the valve body (26) and arranged to cooperate with the piston (34); 4. a bleed fluid conduit (38) operatively coupled to the bleed fluid cavity (36); 5. a venturi arrangement (40) operatively coupled to the bleed fluid conduit (38) to promote evacuation of bleed fluid from the bleed fluid cavity (36) thereby opening the fluid outlet (32) by displacement of the piston (34).

This disclosure is directed to vehicle fuel fill control systems for anticipating vehicle refueling events in order to control the timing of fuel tank depressurization sequences. In a first embodiment, a global positioning system (GPS) is utilized to anticipate the vehicle refueling event prior to initializing the depressurization sequence. In another embodiment, a camera system is utilized to anticipate the refueling event prior to initializing the depressurization sequence. In yet another embodiment, both the GPS and the camera system may be utilized to anticipate the refueling event. By anticipating refueling events, customer wait time for gaining refueling access may be reduced.