Abstract: Methods and systems are provided for an evaporative emissions control system for onboard refueling vapor recovery of a heavy duty vehicle. In one example, a method may include adjusting flow among at least two canisters during canister purging, where the at least two canisters are arranged in a parallel loading and unloading flow direction, to increase flow through a higher loaded canister. Flow may be adjusted using a first valve coupled to the first canister, a second valve coupled to the second canister, and so on for n number of canisters and n number of valves, and a balancing valve used to selectively couple the at least two canisters to a fuel tank.

Abstract: A method for diagnosing an evaporative emission control system that includes during a first state of a vapor blocking valve, determining a first rate of change of a fuel tank vacuum, during a second state of the vapor blocking valve different from the first state, determining a second rate of change of the fuel tank vacuum, and diagnosing an operational condition of the vapor blocking valve based on the first and second rates of change.

Abstract: A method for diagnosing an evaporative emission control system that includes during a first state of a vapor blocking valve, determining a first rate of change of a fuel tank vacuum, during a second state of the vapor blocking valve different from the first state, determining a second rate of change of the fuel tank vacuum, and diagnosing an operational condition of the vapor blocking valve based on the first and second rates of change.

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: 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: 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: 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: 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: A method, comprising: purging fuel vapors from a fuel vapor canister and/or a fuel vapor bleed element to an engine intake with air routed through a transmission bellhousing. In this way, purge air may be warmed by heat generated in the transmission bellhousing during engine operation, thereby increasing desorption efficiency and reducing bleed emissions. Further, purge air may be pressurized in the transmission bellhousing to allow purging operations irrespective of intake manifold vacuum.

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: A method, comprising: purging fuel vapors from a fuel vapor canister and/or a fuel vapor bleed element to an engine intake with air routed through a transmission bellhousing. In this way, purge air may be warmed by heat generated in the transmission bellhousing during engine operation, thereby increasing desorption efficiency and reducing bleed emissions. Further, purge air may be pressurized in the transmission bellhousing to allow purging operations irrespective of intake manifold vacuum.

Abstract: A fuel system for an internal combustion engine uses a fuel pump having an internally mounted pressure-responsive buffer which increases the volume available for fuel within the pump's discharge port upon shutdown of the pump, so as to assist in the mitigation of fugitive hydrocarbon emissions from fuel injectors which might otherwise result from a hot soak of an automotive engine.

Abstract: A fuel system for an internal combustion engine uses a fuel pump having an internally mounted pressure-responsive buffer which increases the volume available for fuel within the pump's discharge port upon shutdown of the pump, so as to assist in the mitigation of fugitive hydrocarbon emissions from fuel injectors which might otherwise result from a hot soak of an automotive engine.