In a case where external electricity feed is being performed, a water temperature threshold Tref is set to a temperature T2 that is lower than in a case where the external electricity feed is not being performed, and canister puree is executed when an engine is in operation and a cooling water temperature Tw is the water temperature threshold Tref or higher. Thereby, it is possible to increase the opportunity to perform the canister purge, and to enhance evaporative emission performance. Furthermore, in the case where the external electricity feed is being performed, a maximum purge rate Pmax is set to a value P2 that is greater than in the case where the external electricity feed is not being performed. Thereby, it is possible to quickly complete the canister purge.

Disclosed is a method for controlling the pressure inside a fuel tank of a motor vehicle, the motor vehicle including a fuel vapor vent circuit connecting the tank to a fuel vapor canister, the vent circuit including an isolation valve for isolating the tank and a rollover valve. The pressure control method includes steps of: determining an activation duration required for the isolation valve to transition from a closed state to a fully open state, referred to as the full opening duration, when a predefined rollover valve closure risk criterion is satisfied: controlling the isolation valve in repeated activations of respective durations that are shorter than the full opening duration.

A method for controlling a pressure inside a fuel tank system on board a vehicle, the fuel tank system having a fuel tank and a venting circuit having at least one controllable pressure relief valve, the vehicle having a source of energy adapted to activate said at least one pressure relief valve so as to move it from a closed position to a pressure relief position. The method entails: detecting a key off event indicative of the vehicle shut-down; determining an amount of energy available at the source of energy; starting at least one pressure relief operation by verifying whether the amount of energy available is lower than a first predetermined threshold amount and, if the verification is positive, activating the at least one pressure relief valve; and terminating the at least one pressure relief operation.

A method is presented wherein during a first condition that includes a fuel tank pressure above a threshold, a fuel tank is fluidically coupled to a fuel vapor canister while a fuel vapor canister vent path is restricted, and a degree of restriction of the fuel vapor canister vent path is modulated. Modulating the degree of restriction of the fuel vapor canister vent path allows a fuel tank to be depressurized at a controlled rate. In this way, excess fuel tank pressure can be relieved, even if a vehicle engine is not operating in a combustion mode.

Determining the thermodynamic state of fuel includes opening the venting connection to release the tank pressure while monitoring the derivative pressure (dP/dt), closing the venting connection when one of the following conditions is met, the derivative pressure (dP/dt) is lower than a predetermined threshold DP1 or the opening time t1 reaches a predetermined value, if the closing of the venting connection occurs when the opening time t1 reaches the said predetermined value, determining that the fuel is boiling and aborting the method if the closing of the venting connection occurs when the derivative pressure (dP/dt) is lower than the said threshold DP1, measuring an initial tank pressure at the closing of the venting connection, measuring the final tank pressure after a closure time t2, calculating the pressure variation (P/t2), comparing the pressure variation (P/t2) with a first threshold PV1, if the pressure is lower then aborting the method.

Methods and systems are provided for diagnosing a vehicle fuel system for a presence or absence of undesired evaporative emissions. In one example, a method comprises conducting a test for undesired evaporative emissions stemming from a fuel system of a vehicle via in a first operating mode, evacuating the fuel system to a variable vacuum level through an entirety of a fuel vapor canister configured to capture and store fuel vapors, and in a second operating mode, evacuating the fuel system to the variable vacuum level through a portion of the fuel vapor canister. In this way, the diagnostic may be conducted in an environmentally friendly fashion, where analysis of a bleed-up portion of the test is not impacted by fuel volatility at the time of the diagnostic.

A ventilation flow rate regulator for a pressurised tank of a vehicle. The regulator includes a body including a gas inlet and a gas outlet, and at least one restrictor mounted movably relative to the body. The restrictor is mounted to reduce a cross-section of at least one path of a gas flow proceeding from the inlet to the outlet, when a flow rate at the inlet is greater than a predetermined threshold. The regulator is arranged so that the cross-section remains non-zero irrespective of a flow rate.

Methods and systems are provided for estimating a level of water in real time for a vehicle and using the said estimation to perform one or more vehicle control strategies. In one example, a method may include adjusting a valve in a fuel system of the vehicle responsive to a level of water through which the vehicle is passing. In this way, water inhalation into the vehicle fuel system may be avoided.

A shutoff vent is disclosed. A main body has a first end and a second end. The main body defines a first opening towards the first end, a second opening towards the second end, and a mating port between the first opening and the second opening. The first opening and the second opening are in communication through the mating port to define a gas passageway. A translatable plug is disposed within the main body, and the gas passageway extends past the translatable plug. The translatable plug is configured to reversibly translate towards the second end to sealably obstruct the mating port. In some examples, the translatable plug is configured to translate towards the second end when force is applied to the translatable plug from the first end.

A fuel cap detection system includes a charcoal canister, a notification system, and an electronic controller. The charcoal canister is connected to a fuel tank of a vehicle, the charcoal canister includes a vent valve. The notification system is configured to notify a user when a fuel cap is incorrectly positioned. The electronic controller is configured to perform a leak detection test on the fuel tank by activating the vent valve in the charcoal canister to determine whether the fuel cap is positioned incorrectly, and determine an intent of the user to reposition the fuel cap while the notification system notifies the user that the fuel cap is incorrectly positioned.