Abstract: Methods and systems are provided for a fuel vapor canister with a modular configuration that may include a number of physically and releasably coupled canister modules, each module including a temperature sensor embedded therein and filled with one of a number of adsorbents. The temperature sensors may be utilized in combination with information regarding module position and the adsorbents within each module to indicate whether one or more of the individual canister modules are not functioning as desired, where such indications are determined during either refueling events, or during canister purging events. In this way, costs associated with servicing fuel vapor canisters may be reduced, the lifetime of fuel vapor canisters may be improved, an overall reduction in undesired evaporative emissions may be achieved, and the capacity of the canister may be readily adjusted based on emissions standards.

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 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: 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: Methods and systems are provided for detecting a fuel tank oil-canning event during conditions when a vacuum is applied to the fuel tank, such as during a fuel system leak test or during purging of a fuel system canister. In one example, a method may include comparing the fuel tank pressure changes during a leak test to changes in fuel tank temperature or fill level and indicating fuel tank oil-canning in response to a higher than threshold rise in fuel tank pressure during or following application of vacuum to the fuel tank while each of a fuel temperature and fill level remain unchanged. By detecting fuel tank oil-canning accurately, appropriate countermeasures can be taken.

Abstract: Systems are provided for a fuel system comprising an external refueling request switch accessible at or near a refueling door, thus enabling methods that may include initiating depressurization of a fuel tank responsive to an operator engaging the refueling request switch. The status of depressurization may be communicated to the operator via on one or more LED displays located either inside the refueling assembly or located at the refueling door. In this way, refueling requests may be initiated by a refueling operator, and by relaying the status of depressurization to the operator, any confusion on the part of the operator may be avoided.

Abstract: A method for an evaporative emissions leak test, comprising: adjusting a pressure threshold based on a fuel volatility of a fuel contained in a fuel tank; and performing the evaporative emissions leak test based on the adjusted pressure threshold. By determining fuel volatility and adjusting a pressure threshold based on the fuel volatility, a more robust and accurate evaporative emissions leak test may be employed without adding additional components to a fuel system.

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: Methods and systems for inferring a fuel level in a fuel tank based on temperature changes in a carbon canister are disclosed. In one example approach a method comprises, indicating a fuel level in a fuel tank based on a temperature change of adsorbent in a carbon canister during refueling.

Abstract: Methods and systems for controlling a locking mechanism on a fuel cap for refueling a vehicle are disclosed. In one example approach, a method comprises venting a fuel tank into a vapor absorbent canister in response to a request to refuel and unlocking the fuel cap in response to a predetermined temperature change in said canister.

Abstract: A method for detecting blockage within a recirculation tube of the evaporative emission control system of a PHEV measures the rise in interior temperature of a canister of the EVAP system, during the process of refueling, and notes an initial state of loading of the canister before refueling, indicative of the amount of hydrocarbons contained within the canister It is inferred that the recirculation tube is operative reliably if the rise in canister temperature is below a pre-determined temperature value.

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 an dedicated valve position sensor.

Abstract: Systems are provided for a fuel system comprising an external refueling request switch accessible at or near a refueling door, thus enabling methods that may include initiating depressurization of a fuel tank responsive to an operator engaging the refueling request switch. The status of depressurization may be communicated to the operator via on one or more LED displays located either inside the refueling assembly or located at the refueling door. In this way, refueling requests may be initiated by a refueling operator, and by relaying the status of depressurization to the operator, any confusion on the part of the operator may be avoided.

Abstract: A method is provided, comprising indicating a fuel vapor canister load based on a steady-state fuel vapor circulation rate 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: 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: A method and system for conducting leak detection in an evaporative emission control system. The method performs a pressure-based leak test at selected intervals. The pressure-based test includes pressurizing the system, using a pump. Then, the system monitors pressure for a selected period. If system pressure falls below a threshold value during the selected period, the system identifies an initial leak. Upon identifying the initial leak, the system substitutes a vacuum-based leak test at each selected interval. The vacuum-based test includes evacuating the system, using the pump. The system then monitors system pressure for a selected period. If system pressure rises above a threshold value during the selected period, then the system identifies a subsequent leak. Upon receiving notification that the initial leak has been repaired, the system returns to pressure-based leak testing. Where a single pump is used, that pump is configured both for system pressurization and evacuation.

Abstract: A method for a fuel system is provided, comprising adjusting a volume of a sealed fuel tank while maintaining spatial compartmentalization of bulk fuel within the sealed fuel tank, and indicating degradation of the sealed fuel tank based on a change in fuel tank pressure. In this way, the fuel tank may be tested for leaks without being unsealed, and without engaging the fuel pump or other elements of the fuel delivery system.

Abstract: Methods and systems are provided for detecting loss of communication in a vehicle network. In one example, a method may include determining a diagnostic time threshold based on an estimated duration for failure of vehicle operation under current operating conditions due to a loss of communication with a control module in the vehicle network. Further, in response to a duration of loss of communication exceeding the time threshold, a loss of communication DTC may be activated.

Abstract: A method is provided, comprising terminating a pressure rise portion of an engine-off natural vacuum test based on an initial rate of change of a fuel system pressure upon sealing a fuel system; and initiating a vacuum portion of the engine-off natural vacuum test responsive to suspending the pressure rise portion. The initial rate of change may indicate a likelihood of the pressure rise portion reaching a pressure rise threshold. In this way, the vacuum portion of the test may be initiated earlier, increasing the likelihood of a conclusive result being obtained during a test time limit.

Abstract: Methods and systems for passively purging a hydrocarbon trap in an engine intake in a vehicle are disclosed. In one example approach, a method comprises, in response to an ambient temperature decrease during an engine off condition while a fuel tank is sealed from atmosphere, delivering fuel stored in a hydrocarbon trap in an intake of the engine to a fuel vapor canister coupled to the fuel tank in an emission control system.