SYSTEMS AND METHODS FOR PREVENTING FUEL TANK OVERFILLING

• US 20170292476A1
• Filed: 04/11/2016
• Published: 10/12/2017
• Est. Priority Date: 04/11/2016
• Status: Active Application

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M.
• Granted Patent: US 10,288,013 B2
• Time in Patent Office: Days
• CPC Class Codes: B60K 15/03504 adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems
• CPC Class Codes: B60K 15/03519 Valve arrangements in the vent line
• CPC Class Codes: B60K 2015/03514 with vapor recovery means
• CPC Class Codes: B60K 2015/03576 Venting during filling the reservoir
• CPC Class Codes: B60K 2015/03585 by gas pressure
• CPC Class Codes: B67D 7/04 for transferring fuels, lubricants or mixed fuels and lubricants
• CPC Class Codes: B67D 7/08 Arrangements of devices for controlling, indicating, metering or registering quantity or price of liquid transferred arrangement of flow- or pressure-control valves B67D7/36; computing, calculating, counting G06; coin-freed apparatus for dispensing fluids G07F13/00; prepayment devices for metering liquids G07F15/00
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation

Abstract

Methods and systems are provided for preventing fuel tank overfilling during refueling events, wherein overfilling of the fuel tank is prevented by delivering a pressure pulse to the fuel tank responsive to a fuel fill level reaching a predetermined threshold, or responsive to an attempt to add additional fuel subsequent to the fuel fill threshold being reached. In one example, an onboard pressure vessel is actively pressurized via an onboard pump, where the pressure may be actively released and routed to the fuel tank to induce an automatic shutoff of a refueling dispenser pump under predetermined conditions. In this way, automatic shutoffs of refueling dispenser pumps may be rapidly and reliably induced, thus preventing fuel tank overfilling, prolonging the lifetime of fuel vapor storage canisters, and reducing undesired evaporative emissions.

Claims

1. A method comprising:

storing pressure in a vessel external to a fuel tank that supplies fuel to a vehicle engine; and

selectively coupling the vessel to the fuel tank to pressurize the fuel tank to a predetermined pressure threshold responsive to an indication that a fuel level in the fuel tank has reached a predetermined fuel fill level during a refueling event.

2. The method of claim 1, wherein the predetermined pressure threshold induces an automatic shutoff of a refueling dispenser, the refueling dispenser supplying fuel to the fuel tank during the refueling event.

3. The method of claim 1, wherein the stored pressure in the vessel is atmospheric air, the atmospheric air supplied to the vessel via an onboard pump means.

4. The method of claim 1, further comprising:

capturing and storing fuel tank vapors in a fuel vapor canister coupled to the fuel tank; and

wherein coupling the vessel to the fuel tank to pressurize the fuel tank further couples the vessel to the fuel vapor canister.

5. The method of claim 4, further comprising:

desorbing fuel tank vapors from the fuel vapor canister during coupling the vessel to the fuel tank to pressurize the fuel tank; and

wherein

pressurizing the fuel tank routes the desorbed fuel vapors to the fuel tank.

6. The method of claim 1, further comprising:

uncoupling the vessel from the fuel tank responsive to pressure in the fuel tank reaching the predetermined pressure threshold.

7. The method of claim 6, wherein uncoupling the vessel from the fuel tank further comprises:

indicating a decrease in fuel tank pressure subsequent to the fuel tank reaching the predetermined pressure threshold.

8. The method of claim 6, further comprising:

recoupling the vessel to the fuel tank to pressurize the fuel tank to the predetermined pressure threshold responsive to an indication of fuel being added to the fuel tank subsequent to the predetermined fuel fill level being reached.

9. The method of claim 8, wherein the indication of fuel being added to the tank subsequent to the predetermined fuel fill level being reached comprises a fuel tank pressure increase.

10. The method of claim 2, wherein coupling the vessel to the fuel tank to pressurize the fuel tank to a predetermined pressure threshold reduces a time constant between an indication to pressurize the fuel tank, and when the fuel tank pressure reaches the predetermined pressure threshold as compared to other means such as a fill limit vent valve designed to close and seal the fuel tank responsive to fuel level reaching the predetermined fuel fill level.

11. A system for a vehicle, comprising:

a fuel tank in a vehicle fuel system coupled to a fuel vapor canister in a vehicle evaporative emissions control system via a vapor recovery line;

a fuel tank isolation valve positioned in the vapor recovery line between the fuel tank and the fuel vapor canister;

an onboard pump positioned in a vent line between the fuel vapor canister and atmosphere, the onboard pump a component of an evaporative level check monitor (ELCM) and wherein the ELCM additionally includes a changeover valve (COV) configurable in a first position and a second position;

a pressure vessel coupled to the vent line via a vessel line between the onboard pump and the fuel vapor canister;

a vessel valve positioned in the vessel conduit between the pressure vessel and the vent line;

a canister purge valve positioned in a purge line between the fuel vapor canister and an intake manifold of a vehicle engine;

an evaporative emissions control system pressure sensor; and

a controller, storing instructions in non-transitory memory, that when executed, cause the controller to;

command or maintain closed the fuel tank isolation valve and the canister purge valve;

command open the vessel valve;

configure the COV in the second position and activate the onboard pump to pressurize the evaporative emissions control system and pressure vessel;

command closed the vessel valve responsive to pressure in the evaporative emissions control system reaching a predetermined pressure threshold to store the pressure; and

control the vessel valve responsive to a fuel tank refueling event.

12. The system of claim 11, wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:

indicate an absence of undesired evaporative emissions in the evaporative emissions system and pressure vessel responsive to pressure in the evaporative emissions control system reaching the predetermined pressure threshold during pressurizing the evaporative emissions control system and pressure vessel.

13. The system of claim 12, further comprising:

a fuel level sensor;

a fuel tank pressure sensor; and

wherein

the controller is further configured with instructions stored in non-transitory memory, that when executed cause the controller to;

responsive to a request for refueling, command open the fuel tank isolation valve, command the COV in the ELCM to the first position to couple the fuel vapor canister to atmosphere via the vent line, command or maintain closed the canister purge valve; and

responsive to an indication that a fuel fill level in the fuel tank has reached a predetermined fuel fill level during refueling;

command open the vessel valve, configure the COV in the second position and activate the onboard pump to pressurize the evaporative emissions system and fuel system; and

responsive to an indication that pressure in the fuel tank has reached a first predetermined fuel tank pressure threshold, where the first predetermined fuel tank pressure threshold comprises a pressure sufficient to induce an automatic shutoff of a refueling dispenser pump;

command closed the vessel valve, deactivate the onboard pump, and configure the ELCM COV in the first position to couple the fuel tank and fuel vapor canister to atmosphere.

14. The system of claim 13, wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:

monitor fuel tank pressure subsequent to pressure in the tank reaching the first predetermined threshold and responsive to the vessel valve being commanded closed and the onboard pump being deactivated; and

responsive to a subsequent pressure increase in the fuel tank and/or an indication of fuel level increasing;

pressurize the fuel tank by again commanding open the vessel valve, configuring the ELCM COV in the second position, and activating the onboard pump until the first predetermined fuel tank pressure threshold is reached, and then command closed the vessel valve, deactivate the onboard pump, and configure the ELCM COV in the first position;

where the subsequent pressure increase may occur any number of times.

15. The system of claim 13, further comprising:

a temperature sensor positioned in the fuel vapor canister close-coupled to the vapor recovery line; and

wherein

the controller is further configured with instructions stored in non-transitory memory, that when executed cause the controller to;

responsive to a temperature decrease greater than a predetermined threshold temperature decrease during pressurizing the fuel tank;

command closed the vessel valve, configure the ELCM COV in the first position, deactivate the onboard pump; and

command closed the fuel tank isolation valve to increase pressure in the fuel tank to the first predetermined fuel tank pressure threshold.

16. The system of claim 13, wherein the controller is further configured with instructions stored in non-transitory memory, that when executed cause the controller to:

responsive to an indication of the presence of undesired evaporative emissions in the evaporative emissions system and/or the pressure vessel during pressurizing the evaporative emissions system and pressure vessel;

maintain the vessel valve closed, the onboard pump off, and the ELCM COV in the first position responsive to an indication that the fuel fill level in the fuel tank has reached the predetermined fuel fill level during refueling; and

command closed the fuel tank isolation valve to increase pressure in the fuel tank to the first predetermined fuel tank pressure threshold.

17. A method for a vehicle comprising:

inducing an automatic shutoff of a refueling dispenser that supplies fuel to a vehicle fuel tank during a refueling event by directing a pressure wave from an evaporative emissions control system of the vehicle to the fuel tank responsive to a fuel fill level in the fuel tank reaching a predetermined fuel fill level;

where the automatic shutoff is induced via pressure in the fuel tank reaching a predetermined fuel tank pressure threshold.

18. The method of claim 17, wherein the fuel vapors are stored in a vapor canister positioned in the evaporative control system, and the pressure wave passes through the canister desorbing vapors stored therein and routing the desorbed vapors into the fuel tank.

19. The method of claim 17, wherein the pressure wave originates from a pressure vessel, the pressure vessel selectively pressurized with atmospheric air actively pumped into the pressure vessel via an onboard pump positioned in the evaporative emissions system.

20. The method of claim 17, wherein the pressure wave induces the automatic shutoff of the refueling dispenser with a time constant that is faster than inducing an automatic shutoff via a mechanical or electrical valve configured to close and seal the fuel tank responsive to fuel level reaching the predetermined fuel fill level.