System and methods for preventing premature refueling shutoff

Patent metadata

Field	Value
Publication number	US-9732685-B2
Application number	US-201514938565-A
Country	US
Kind code	B2
Filing date	Nov 11, 2015
Priority date	Nov 11, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Methods and systems are provided for conducting a refueling operation. In one example, during the refueling event, fuel vapors may be routed from a fuel tank to a first fuel vapor canister, and upon indication that the first fuel vapor canister is saturated with hydrocarbons, fuel vapors may be routed from the fuel tank to a second fuel vapor canister thus bypassing the first fuel vapor canister, without input from a powertrain control module. In this way, during refueling, saturated fuel vapor canisters are bypassed such that resistance to fuel vapor flow may be decreased, thus reducing the likelihood of premature shutoffs of a refueling dispenser.

First claim

The invention claimed is:

1. A method comprising:
during refueling a fuel tank which supplies fuel to an engine, venting the fuel tank to atmosphere through a vapor storage system comprising first and second fuel vapor canisters in series;
routing vapors from the fuel tank to the first fuel vapor canister; and
responsive to a temperature of the first fuel vapor canister above a predetermined threshold:
routing vapors from the fuel tank around the first fuel vapor canister to the second fuel vapor canister.

2. The method of claim 1 , further comprising:
monitoring the first fuel vapor canister temperature via a first thermistor positioned at a first vent port of the first fuel vapor canister, where the routing includes routing vapors directly from the fuel tank completely around the first fuel vapor canister and directly to the second fuel vapor canister; and
wherein the temperature of the first fuel vapor canister above the predetermined threshold indicates that the first fuel vapor canister is saturated with fuel vapor.

3. The method of claim 2 , further comprising:
powering a circuit that includes the first thermistor via an on-board power source; and
completing the circuit responsive to the first fuel vapor canister temperature above the predetermined threshold, wherein the engine is an engine of a road vehicle.

4. The method of claim 3 , wherein completing the circuit is based on a temperature dependent change in a resistance of the circuit.

5. The method of claim 3 , further comprising:
coupling and uncoupling the fuel tank to the second fuel vapor canister via a first bypass valve, the first bypass valve housed within a first bypass conduit running parallel to the first fuel vapor canister; and
wherein routing vapors from the fuel tank around the first fuel vapor canister to the second fuel vapor canister further comprises opening the first bypass valve.

6. The method of claim 5 , wherein the first bypass valve is opened responsive to completing the circuit when the first fuel vapor canister temperature is above the predetermined threshold; and
wherein the first bypass valve is maintained open responsive to the first fuel vapor canister temperature above the predetermined threshold being maintained, and maintained closed responsive to the first fuel vapor canister temperature below the predetermined threshold.

7. The method of claim 2 , further comprising:
indicating one or more automatic shut-offs of a refueling dispenser during the refueling the fuel tank.

8. The method of claim 7 , further comprising:
indicating a tank fill level via a fuel level indicator housed within the fuel tank;
indicating whether the tank fill level is at capacity responsive to one or more automatic shutoffs of the refueling dispenser during refueling; and
responsive to determining that the tank fill level is at capacity, indicating an absence of restrictions in the vapor storage system.

9. The method of claim 8 , wherein responsive to an indication that one or more automatic shutoffs occurred during the refueling, and further responsive to an indication that the fuel tank is not full and that fuel vapors were not routed from the fuel tank around the first fuel vapor canister to the second fuel vapor canister:
indicating a restriction in the vapor storage system responsive to the first fuel vapor canister temperature below the predetermined threshold during refueling; and
indicating malfunction in one or more of the first thermistor and/or a first bypass valve responsive to the first fuel vapor canister temperature above the predetermined threshold during refueling.

10. The method of claim 1 , wherein routing vapors from the fuel tank around the first fuel vapor canister to the second fuel vapor canister and routing vapors from the fuel tank to the first fuel vapor canister is achieved passively without powertrain control module input.

11. The method of claim 2 , further comprising:
monitoring a second fuel vapor canister temperature via a second thermistor positioned at a second vent port of the second fuel vapor canister, wherein monitoring the first fuel vapor canister temperature and the second fuel vapor canister temperature includes indicating a first fuel vapor canister loading state and a second fuel vapor canister loading state; and
responsive to completion of refueling:
updating the first fuel vapor canister loading state and the second fuel vapor canister loading state to indicate an updated loading state of the first fuel vapor canister and the second fuel vapor canister.

12. The method of claim 11 , further comprising:
selectively coupling a first purge port of the first fuel vapor canister and a second load port of the second fuel vapor canister to an intake manifold of the engine through a canister purge valve;
selectively coupling the first vent port of the first fuel vapor canister and a second vent port of the second fuel vapor canister to atmosphere through a canister vent valve; and
purging fuel vapors stored in a vapor adsorbent, which is housed in each of the first fuel vapor canister and the second fuel vapor canister, into the intake manifold of the engine under predetermined engine operating conditions;
purging fuel vapors further comprising: commanding open the canister purge valve and commanding open or maintaining open the canister vent valve to direct air through the vapor storage system to the intake manifold of the engine to purge the vapor storage system and fuel vapor canister of hydrocarbons.

13. The method of claim 12 , further comprising:
adjusting one or more fuel vapor purging parameters based on the updated loading state of the first fuel vapor canister and the second fuel vapor canister.

14. A method comprising:
during refueling a fuel tank which supplies fuel to an engine, venting the fuel tank to atmosphere through a vapor storage system comprising a first fuel vapor canister and a second fuel vapor canister arranged in series, each comprising a load port, a vent port, and a purge port;
routing vapors from the fuel tank to the load port of the first fuel vapor canister;
monitoring a first fuel vapor canister temperature via a first thermistor positioned at the vent port of the first fuel vapor canister and monitoring a second fuel vapor canister temperature via a second thermistor positioned at the vent port of the second fuel vapor canister; and
responsive to an indication that the first fuel vapor canister temperature is above a predetermined threshold:
routing vapors from the fuel tank around the first fuel vapor canister to the load port of the second fuel vapor canister.

15. The method of claim 14 ,
wherein adsorption of fuel tank vapors by the first fuel vapor canister and the second fuel vapor canister results in an increase in temperature, whereby a first fuel vapor canister loading state and a second fuel vapor canister loading state may be indicated based on the first fuel vapor canister temperature and the second fuel vapor canister temperature indicated during refueling; and
wherein the first fuel vapor canister loading state and the second fuel vapor canister loading state is updated after completion of refueling to indicate an updated first fuel vapor canister loading state and second fuel vapor canister loading state.

16. The method of claim 15 , further comprising:
purging fuel vapors stored in a vapor adsorbent, which is housed in each of the first fuel vapor canister and the second fuel vapor canister into the engine to be used as fuel under predetermined engine operating conditions; and
adjusting a fuel

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• F02M25/0836

  Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold · CPC title

• F02M25/08 Primary

  adding fuel vapours drawn from engine fuel reservoir {(electrical control of purge system F02D41/003)} · CPC title

• F02D41/0032 Primary

  Controlling the purging of the canister as a function of the engine operating conditions · CPC title

• B60K15/035

  characterised by venting means · CPC title

• F02D41/003

  Adding fuel vapours, e.g. drawn from engine fuel reservoir · CPC title