Hybrid vehicle fuel vapor canister

• US 10,156,210 B2
• Filed: 09/27/2013
• Issued: 12/18/2018
• Est. Priority Date: 09/27/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M., Yang, Dennis Seung-Man
• Primary Examiner(s): Hamaoui, David
• Assistant Examiner(s): SCHARPF, SUSAN E
• Application Number:
  US14/039,964
• Publication Number:
  US 20150090233A1
• Time in Patent Office: 1,908 Days
• Field of Search: 123520, 123518, 123519, 123521, 180314
• CPC Class Codes: F02M 2025/0881 with means to heat or cool the canister
• CPC Class Codes: F02M 25/08 adding fuel vapours drawn from engine fuel reservoir electrical control of purge system F02D41/003
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02M 25/0827 by monitoring engine running conditions
• CPC Class Codes: F02M 25/0836 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 Class Codes: F02M 25/0854 Details of the absorption canister

Abstract

Embodiments for controlling fuel vapors are provided. In one example, a method comprises initiating a purge of a fuel vapor canister responsive to a temperature profile at a vent side of the fuel vapor canister. In this way, release of fuel vapors to the atmosphere may be reduced.

Claims

1. A hybrid vehicle system, comprising:

an engine;

a fuel tank configured to supply fuel to the engine for combustion, the fuel tank coupled to a refueling line and to a conduit configured to release fuel vapor from the fuel tank;

a fuel vapor canister coupled to the conduit and configured to trap the fuel vapor released from the fuel tank;

a vent line coupling the fuel vapor canister to atmosphere;

a purge line coupling the fuel vapor canister to the engine;

a temperature sensor positioned in the fuel vapor canister near a vent port coupling the fuel vapor canister to the vent line;

a plurality of heaters embedded in the fuel vapor canister; and

a controller storing instructions for;

detecting bleed-through of fuel vapor out of the fuel vapor canister based on output of the temperature sensor indicating that a vent-side temperature of the fuel vapor canister has a temperature profile including an increase in the vent-side temperature followed by a decrease in the vent-side temperature; and

if bleed-through is detected,

opening a canister purge valve positioned in the purge line to route the trapped fuel vapor to the engine, the trapped fuel vapor forming a purge flow through the purge line;

after opening the canister purge valve and responsive to a hydrocarbon concentration of the purge flow reaching an upper threshold concentration, activating at least one heater of the plurality of heaters; and

if the hybrid vehicle is currently propelled by a motor and not the engine, starting the engine prior to opening the canister purge valve.

2. The system of claim 1, wherein the plurality of heaters comprises a first heater positioned near the vent port of the fuel vapor canister, and a second heater positioned near a purge port of the fuel vapor canister, the purge port coupling the fuel vapor canister to the purge line, the first heater positioned nearer to the vent port than the second heater, the temperature sensor positioned nearer to the vent port than the purge port, and the temperature sensor positioned between the first heater and the vent port.

3. The system of claim 2, wherein the controller stores instructions for activating the first heater prior to activating the second heater.

4. The system of claim 1, further comprising, when the hybrid vehicle is propelled by the motor and not by the engine, adjusting the plurality of heaters to maintain a temperature of the fuel vapor canister at a designated temperature, and wherein activating the at least one heater of the plurality of heaters comprises adjusting the at least one heater to increase the temperature of the fuel vapor canister above the designated temperature.

5. The system of claim 1, further comprising a canister check valve positioned in the purge line and a fuel tank isolation valve positioned in a fuel line coupling the fuel tank to the fuel vapor canister, and wherein the controller stores instructions to open the fuel tank isolation valve during a fuel tank refill event to route the fuel vapor from the fuel tank to the fuel vapor canister.

6. The system of claim 1, wherein the temperature sensor is positioned in the fuel vapor canister adjacent the vent port, the vent port spaced apart from a purge port of the fuel vapor canister, the purge port fluidly coupled to the purge line.

7. The system of claim 1, further comprising an oxygen sensor fluidically coupled to the purge line, and wherein the controller stores further instructions for determining a purge flow rate of the purge flow based on output from the oxygen sensor.

8. The system of claim 1, wherein the instructions for detecting bleed-through of fuel vapor out of the fuel vapor canister based on output of the temperature sensor comprises instructions for detecting bleed-through of fuel vapor out of the fuel vapor canister responsive to a temperature measured by the temperature sensor increasing for a duration followed by the temperature subsequently decreasing.

9. A method for managing fuel vapors in a hybrid vehicle configured to be propelled by a motor or by an engine, the method comprising:

during non-purge conditions while the engine is inactive, routing fuel vapors from a fuel tank to a fuel vapor canister and detecting fuel vapors exiting the fuel vapor canister to atmosphere based on a temperature of an atmosphere side of the fuel vapor canister reaching a peak temperature and subsequently decreasing;

if fuel vapors exiting the fuel vapor canister are detected, starting the engine and opening a canister purge valve to route fuel vapor in the fuel vapor canister to the engine for combustion, thereby forming a purge flow in a purge line coupled between the fuel vapor canister and the engine; and

activating a heater of the fuel vapor canister responsive to onset of an endothermic reaction in the fuel vapor canister as detected by a concentration of hydrocarbons in the purge flow increasing to a first threshold level.

10. The method of claim 9, wherein routing fuel vapors from the fuel tank to the fuel vapor canister comprises opening a fuel tank isolation valve when fuel tank pressure exceeds a threshold.

11. The method of claim 9, wherein the heater is a first heater of a plurality of heaters of the fuel vapor canister, and wherein activating the heater comprises activating the first heater and then activating one or more additional heaters of the plurality of heaters successively in a direction of purge flow through the fuel vapor canister.