Abstract: Methods and systems are provided for accurately confirming fuel tank depressurization before unlocking a fuel door to enable refueling. Following a refueling request, a fuel system may be sealed from the atmosphere while one or more fuel system valves are adjusted to divert fuel tank pressure or vacuum to an engine intake. Depressurization may be inferred based on the presence of air or vapor flow into the intake as sensed by a manifold airflow sensor.

Abstract: A system for an engine, comprising: a fuel tank; a thermal regulator comprising a phase-change material, the thermal regulator coupled to the fuel tank; and an engine coolant passage positioned to transfer thermal energy between engine coolant and the phase-change material. In this way, the temperature of the fuel tank may be managed passively by the phase-change material, and actively by engine coolant, thereby allowing heat energy to be shunted away from the fuel tank, cooling the fuel within the fuel tank, and reducing fuel vapor concentration, thus enabling a fuel vapor canister with a reduced size.

Abstract: A system for an engine, comprising: a fuel vapor canister coupled to a fuel tank; a thermal jacket comprising a phase-change material, the thermal jacket spatially sheathing the fuel vapor canister; and an engine coolant passage positioned to transfer thermal energy between engine coolant and the phase-change material. In this way, the phase-change material may buffer the temperature of the fuel vapor canister by absorbing heat generated during hydrocarbon adsorption, and returning the heat to the vapor canister during hydrocarbon desorption. By coupling the phase-change material to engine coolant, the thermal capacity of the thermal jacket can be increased, as heated coolant can thus transfer thermal energy to the phase-change material to replace the thermal energy transferred to the canister during hydrocarbon desorption.

Abstract: Systems and methods for operating an engine with a fuel vapor recovery system are disclosed. In one example approach, a method for an engine with a fuel vapor recovery system including a multi-tubular fuel vapor canister comprises directing air through a first set of adsorbent passages in the fuel vapor canister to purge fuel vapor therefrom while not directing air through a second set of adsorbent passages in the fuel vapor canister; and directing air through the second set of adsorbent passages to purge fuel vapor therefrom while not directing air through the first set of adsorbent passages.

Abstract: A method for a vehicle, comprising: depressurizing a fuel tank while restricting access to a fuel fill line responsive to receiving a refueling request from a refueling request module located external to a vehicle cabin; and allowing access to the fuel fill line responsive to the fuel tank pressure decreasing below a threshold. In this way, all of the steps of a refueling procedure can be carried out entirely outside of a vehicle.

Abstract: A centrifugal fan is provided that includes a main plate configured to be rotated about a rotational axis, a shroud, having a suction opening through which air is suctioned in, and a plurality of blades arranged in a circumferential direction between the main plate and the shroud to allow the air suctioned in through the suction opening to flow from a front edge to a rear edge of each blade. Assuming a first cross section, a second cross section, a third cross section, and a fourth cross section of each blade sequentially taken at layers from the shroud to the main plate, a front edge of the first cross section is located farther from the rotational axis than a front edge of the fourth cross section, and a rear edge of the first cross section is located closer to the rotational axis than a rear edge of the fourth cross section.

Abstract: Methods and systems are provided for improving air intake system hydrocarbon trap purging during engine-off time in a hybrid electric vehicle. One method includes opening the throttle during vehicle motion under battery operation and allowing airflow through the trap to purge its contents into the fuel canister via the canister purge valve. Upon transition into the engine-on mode, fuel vapors are released from the canister into the engine intake.

Abstract: A method for a fuel system, comprising: indicating a leak in a fuel tank following applying a vacuum to the fuel tank by running a vacuum pump in a first direction; then purging a fuel vapor canister to the fuel tank by running the vacuum pump in a second direction, opposite the first direction. In this way, the fuel vapor canister may be purged of its contents following a fuel system leak check. This may reduce bleed emissions while increasing the efficiency of the vehicle, as the engine does not need to be turned on in order to purge the canister.

Abstract: A method for a plug-in hybrid electric vehicle, comprising: during a first condition, including an engine-off condition and the plug-in hybrid electric vehicle coupled to an external power source; heating a fuel vapor canister based on a fuel tank vacuum; and opening a fuel tank isolation valve to draw heated vapors into a fuel tank. In this way, a passive purge operation may be executed, thereby purging the fuel vapor canister without forcing the engine to turn on. Thus, the vehicle may be operated at peak fuel economy without increasing emissions.

Abstract: A method for a vehicle fuel system, comprising: during an engine-off condition, including an ambient temperature within a threshold range, operating a cooling fan to increase a fuel tank vacuum; and indicating leaks in the vehicle fuel system based on the increased vacuum. In this way, an EONV test may be run at mild ambient temperatures which would not otherwise result in the development of adequate fuel tank vacuum to pass the EONV test.

Abstract: Systems and methods for improving fuel vapor purging for a vehicle are presented. In one example, a fuel vapor storage canister vent valve is housed in a fuel vapor storage canister for the purposes of heating contents of the fuel vapor storage canister and venting the fuel vapor storage canister to atmosphere.

Abstract: Systems and methods for internal orifice characterization in an evaporative leak check module are disclosed. In one example approach, a method comprises operating a pump to draw air from an emission control system through an orifice to obtain a reference pressure, and indicating a leak in response to pressure in the emission control system remaining above a threshold pressure while operating the pump to decrease pressure in the emission control system, where the threshold pressure is based on a coded indication and the reference pressure.

Abstract: A method for operating a vehicle system is provided. The method includes monitoring a change in a temperature of the fuel vapor canister coupled to a fuel tank via a canister temperature sensor and adjusting operation of a fuel tank isolation valve based on the change in temperature of the fuel vapor canister.

Abstract: A method for a vehicle, comprising: following a refueling event, venting a capless refueling assembly to a fuel tank; and then executing an evaporative emissions leak test. In this way, residual fuel trapped in the capless refueling assembly may be removed. This, in turn will prevent a pressure build-up in the capless refueling assembly which could lead to the downstream door opening during a leak test, thereby confounding results.

Abstract: A method for a vehicle, comprising: indicating a true fill level of a fuel tank based on a fuel vapor canister temperature profile during a refueling event. In this way, a quantity fuel dispensed over the maximum fill level of the fuel tank may be accounted for, regardless of the fuel level sensor reading.

Abstract: Methods and systems for fuel system leak detection are disclosed. In one example approach, a method comprises, during an engine-on condition, delivering fuel from a fuel tank to one or more cylinders of the engine while the fuel tank is sealed off from atmosphere, and indicating a leak based on pressure in the fuel tank. For example, a leak may be indicated in response to a pressure decrease in the fuel tank greater than an expected pressure decrease, where the expected pressure decrease is based on a fuel level in the fuel tank.

Abstract: A method, comprising: indicating a leak of a first diameter on a canister side of a fuel system following applying a vacuum to the fuel system with a fuel tank isolation valve closed; and indicating a leak of a second diameter on a fuel tank side of the fuel system, based on a vacuum decay in an isolated fuel tank following applying a vacuum to the fuel system with the fuel tank isolation valve open. In this way, an evaporative leak check module with a single reference orifice may be used to determine leaks of multiple sizes in multiple sectors of a fuel system. This may allow current production models to meet more stringent emissions regulations in the future.

Abstract: A method, comprising: indicating leakage on a canister side of a fuel system based on a first fuel system pressure following applying a vacuum to the fuel system with a fuel tank isolation valve closed; and indicating leakage on a fuel tank side of the fuel system based on the first fuel system pressure and a second fuel system pressure following applying a vacuum to the fuel system with the fuel tank isolation valve open. In this way, an ELCM with a single reference orifice may be used to perform a leak test with two different thresholds for leak detection. This may allow vehicles currently in production to meet future emissions standards without costly upgrades to the ELCM.

Abstract: A method for a plug-in hybrid electric vehicle, comprising: during a first condition, including an engine-off condition and the plug-in hybrid electric vehicle coupled to an external power source, cooling a vapor canister based on an ambient temperature. In this way, bleed emissions may be reduced in PHEVs during conditions when the vehicle is parked and recharging at a high ambient temperature.

Abstract: A method for a plug-in hybrid electric vehicle, comprising: during a first condition, including an engine-off condition and the plug-in hybrid electric vehicle coupled to an external power source; heating a fuel vapor canister based on a fuel tank vacuum; and opening a fuel tank isolation valve to draw heated vapors into a fuel tank. In this way, a passive purge operation may be executed, thereby purging the fuel vapor canister without forcing the engine to turn on. Thus, the vehicle may be operated at peak fuel economy without increasing emissions.