Systems and methods for preventing fuel tank overfilling

Patent metadata

Field	Value
Publication number	US-10288013-B2
Application number	US-201615095634-A
Country	US
Kind code	B2
Filing date	Apr 11, 2016
Priority date	Apr 11, 2016
Publication date	May 14, 2019
Grant date	May 14, 2019

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.

First claim

The invention claimed is:

1. A method comprising:
pressurizing a vessel external to a fuel tank that supplies fuel to a vehicle engine; and
while a fuel level in the fuel tank is increasing during a refueling event, selectively coupling the vessel to the fuel tank to pressurize the fuel tank to a predetermined pressure threshold responsive to an indication that the fuel level in the fuel tank has reached a capacity of the fuel tank, where the pressurizing the fuel tank desorbs fuel vapors stored in a fuel vapor storage canister to the fuel tank.

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 pressurizing the vessel further comprises pressurizing the vessel via pumping atmospheric air to the vessel via an onboard pump means.

4. 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.

5. The method of claim 4 , 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.

6. The method of claim 4 , 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 uncoupling the vessel from the fuel tank responsive to the pressure in the fuel tank reaching the predetermined pressure threshold.

7. The method of claim 6 , wherein the indication of fuel being added to the fuel tank subsequent to the uncoupling the vessel from the fuel tank comprises a fuel tank pressure increase.

8. The method of claim 2 , wherein coupling the vessel to the fuel tank to pressurize the fuel tank to the predetermined pressure threshold prevents trickle-filling of the fuel tank.

9. 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 line 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 the pressure vessel;
command closed the vessel valve responsive to a 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.

10. The system of claim 9 , 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 control system and the pressure vessel responsive to the pressure in the evaporative emissions control system reaching the predetermined pressure threshold during pressurizing the evaporative emissions control system and the pressure vessel.

11. The system of claim 10 , further comprising:
a fuel level sensor; and
a fuel tank pressure sensor;
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, and command or maintain closed the canister purge valve;
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 control system and the vehicle 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 COV in the first position to couple the fuel tank and the fuel vapor canister to atmosphere.

12. The system of claim 11 , wherein the controller further stores instructions in non-transitory memory that, when executed, cause the controller to:
monitor fuel tank pressure subsequent to the pressure in the fuel tank reaching the first predetermined fuel tank pressure 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 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 COV in the first position;
where the subsequent pressure increase may occur any number of times.

13. The system of claim 11 , further comprising:
a temperature sensor positioned in the fuel vapor canister close-coupled to the vapor recovery line;
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 COV in the first position, and deactivate the onboard pump; and
command closed the fuel tank isolation valve to increase the pressure in the fuel tank to the first predetermined fuel tank pressure threshold.

14. The system of claim 11 , 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 a presence of undesired evaporative emissions in the evaporative emissions control system and/or the pressure vessel during pressurizing the evaporative emissions system and the pressure vessel:
maintain the vessel valve closed, the onboard pump off, and the 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 fue

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• F02M25/089 Primary

  Layout of the fuel vapour installation · CPC title

• B60K15/03504

  adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems · CPC title

• B60K15/03519

  Valve arrangements in the vent line · CPC title

• B60K2015/03514

  with vapor recovery means · CPC title

• B60K2015/03585

  by gas pressure · CPC title