Abstract: Methods and systems are provided for enabling a vehicle operator to select a desired amount of fuel to add to a fuel tank, and wherein overfilling of the tank is prevented by pressurizing the fuel system with an onboard pump. In one example, the tank may be sealed to induce an automatic shutoff of a refueling dispenser if the fuel level is below the capacity of the tank, and in another example, wherein it is indicated that the tank is full, the fuel system may be pressurized via the pump to induce automatic shutoff of the refueling dispenser and to prevent further overfilling of the tank. In this way, vehicle operators may add desired amounts of fuel to the tank wherein shutoff of the refueling dispenser is automatic, and wherein liquid fuel entering an evaporative emissions control system as a result of overfilling a fuel tank is prevented.

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: Embodiments for controlling fuel vapors are disclosed. In one example, a method comprises during a purge of a fuel vapor canister, adjusting a heater of the fuel vapor canister based on a rate of a purge flow exiting the fuel vapor canister and a concentration of hydrocarbons released from the fuel vapor canister. In this way, a fuel vapor canister purge efficiency may be increased.

Abstract: A method for localizing restrictions in a fuel system during refueling, comprising: monitoring fuel tank pressure, fuel vapor canister temperature, and evaporative leak check module pressure during a refueling event; and responsive to a premature shutoff event, indicating a location of a restriction among a plurality of locations based on whether monitored pressure and temperature changes during the refueling event are greater than respective thresholds. In this way, the cause of a premature shutoff event may be diagnosed without requiring additional sensors within the fuel system.

Abstract: A fuel system is provided, including a fuel tank isolation valve comprising an actuation coil and a latchable valve shaft at least partially disposed within the actuation coil. A controller may be configured to indicate a position of the valve shaft based on a measured current-voltage relationship between the first and second terminal wires during a condition in which the magnetic field generated by actuation coil current has a flux density below a threshold required to adjust a position of the latchable valve shaft. In this way, the position of the latchable valve shaft may be indicated without moving the valve shaft, and without requiring a dedicated valve position sensor.

Abstract: 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.

Abstract: A method is provided, comprising indicating a fuel vapor canister load based on a steady-state pressure in a vapor recovery line during a refueling event; and adjusting a canister purging operation in response to the indicated fuel vapor canister load. Restrictions in the vapor recovery line may increase the rate of fuel vapor canister loading during a refueling event. In this way, an accurate canister load may be determined following a refueling event, and canister purging operations adjusted accordingly.

Abstract: Methods and systems are provided for regulating the flow of fuel vapors exiting a fuel tank. In one example, a method for an engine may include adjusting an amount of fuel vapors flowing through a fuel vapor recirculation line, where the recirculation line may be coupled on a first end to a fuel tank and on an opposite second end to a fuel fill inlet. The valve may be adjusted to a more open position to increase fuel vapor flow through the recirculation line in response to increases in hydrocarbon emissions from a fuel vapor canister, and to a more closed position to reduce fuel vapor flow through the recirculation line in response to increases in hydrocarbon emissions from the fuel fill inlet.

Abstract: Methods and systems for cleaning a capless refueling system in a vehicle are disclosed. In one example approach, a method comprises, in response to a leak detected following a refueling event, cleaning the capless refueling system using engine vacuum.

Abstract: Methods and systems are provided for depressurizing a fuel tank prior to refueling the fuel tank. One example method includes adjusting a latchable refueling valve to a latched open position to enable vapor flow from the fuel tank to a vapor canister at a first rate, and responsive to fuel tank pressure being higher than a first pressure threshold after a pre-determined duration at the latched open position, modifying the latchable refueling valve to an unlatched open position. The unlatched open position of the latchable refueling valve enables a second flow rate for fuel vapors, the second flow rate higher than the first flow rate at the latched open position.

Abstract: A distensible fuel tank included in a vehicle, comprising a housing and a compliance structure coupled to the housing, the compliance structure including a support element coupled to a first side of a structural element and a reinforcing element coupled to a second opposing side of the structural element.

Abstract: Methods and systems are provided for enabling a vehicle operator to select a desired amount of fuel to add to a fuel tank, and wherein overfilling of the tank is prevented by pressurizing the fuel system with an onboard pump. In one example, the tank may be sealed to induce an automatic shutoff of a refueling dispenser if the fuel level is below the capacity of the tank, and in another example, wherein it is indicated that the tank is full, the fuel system may be pressurized via the pump to induce automatic shutoff of the refueling dispenser and to prevent further overfilling of the tank. In this way, vehicle operators may add desired amounts of fuel to the tank wherein shutoff of the refueling dispenser is automatic, and wherein liquid fuel entering an evaporative emissions control system as a result of overfilling a fuel tank is prevented.

Abstract: A method for a fuel system is provided. A vacuum is applied to a fuel vapor canister side of the fuel system, and hydrocarbon breakthrough is indicated responsive to a fuel vapor canister side pressure inflection point indicative of a decay in fuel vapor canister side vacuum. In this way, an evaporative leak check module may perform a leak check on a fuel vapor canister, while hydrocarbon breakthrough from the fuel vapor canister may be indicated without requiring a dedicated hydrocarbon sensor in the canister vent line.

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, 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 for a fuel system, comprising: during a first condition, purging fuel vapor from a fuel vapor canister to a fuel vapor accumulator; and then during a second condition, evacuating fuel vapor from the fuel vapor accumulator to a fuel tank. The fuel vapor accumulator increases the volume of the fuel system, providing a temporary storage for desorbed fuel vapor. In this way, canister breakthrough of hydrocarbons can be mitigated, thereby reducing bleed emissions.

Abstract: Methods and systems are provided for a latchable refueling valve designed to reduce noise associated with opening and closing the valve. In one example, a system may include a valve armature with first and second latch indices formed on an outer diameter of the armature. The latch indices may be rounded and configured to engage with a latch guide to enable rotation between the armature and the latch guide.

Abstract: Methods and systems are provided for regulating the flow of fuel vapors exiting a fuel tank. In one example, a method for an engine may include adjusting an amount of fuel vapors flowing through a fuel vapor recirculation line, where the recirculation line may be coupled on a first end to a fuel tank and on an opposite second end to a fuel fill inlet. The valve may be adjusted to a more open position to increase fuel vapor flow through the recirculation line in response to increases in hydrocarbon emissions from a fuel vapor canister, and to a more closed position to reduce fuel vapor flow through the recirculation line in response to increases in hydrocarbon emissions from the fuel fill inlet.

Abstract: Methods and systems are provided for purging a fuel vapor canister into an engine intake. A method comprises flowing fuel vapors from a fuel tank through a full length of the fuel vapor canister from a first input to a first output on a first opposite side from the first input. The adsorbed fuel vapors may be purged from the fuel vapor canister through a full width in the fuel vapor canister from a second input to a second output on a second opposite side from the second input.

Abstract: Methods and systems are provided for detecting and mitigating the presence of liquid fuel carryover in an evap system of a vehicle in response to a refueling event. In one example, during a first condition, a vacuum pump is activated to pressurize the fuel system responsive to a first fuel tank pressure decay rate being less than a threshold, and responsive to a second fuel tank pressure decay rate being greater than a threshold, the vacuum pump is maintained on until a fuel tank pressure decreases to atmospheric pressure. In this way, liquid fuel carryover can be quickly and accurately diagnosed, such that mitigating actions may be taken to ensure liquid fuel is returned to the tank prior to contacting the adsorbent material within the vapor canister.