Diagnostic for a fuel canister heating system

Patent metadata

Field	Value
Publication number	US-11525422-B1
Application number	US-202117373894-A
Country	US
Kind code	B1
Filing date	Jul 13, 2021
Priority date	Jul 13, 2021
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A vehicle includes a fuel tank, a canister, a first valve, a second valve, a heater, and a controller. The fuel tank is configured to store fuel. The canister is in fluid communication with the fuel tank and is configured to receive and store evaporated fuel from the fuel tank. The first valve is disposed between the fuel tank and the canister. The second valve is disposed between the canister and ambient surroundings. The heater is disposed within the canister. The controller is programmed to, periodically initiate diagnostic tests that are configured to determine if the heater is operating properly, if the heater is unable to turn off, or if the heater is unable to turn on.

First claim

What is claimed is:

1. A vehicle comprising:
a fuel tank configured to store fuel;
a canister in fluid communication with the fuel tank and configured to receive and store evaporated fuel from the fuel tank;
a first valve disposed between the fuel tank and the canister;
a second valve disposed between the canister and ambient surroundings;
a heater disposed within the canister; and
a controller programmed to,
periodically initiate a diagnostic test, the diagnostic test including, opening the first valve, closing the second valve, deactivating the heater, and sensing a vapor pressure within the fuel tank,
in response to the vapor pressure being less than a threshold during the diagnostic test, output a signal indicating that the heater is operating properly, and
in response to the vapor pressure exceeding the threshold during the diagnostic test, output a signal indicating that the heater is unable to turn off.

2. The vehicle of claim 1 , wherein the controller is programmed to,
in response to the vehicle being shutdown prior to initiating the diagnostic test, open the first and second valves, and deactivate the heater, and
in response to a predetermined period of time elapsing after the vehicle being shutdown and prior to initiating the diagnostic test, close the first valve, maintain an open condition of the second valve, maintain a deactivated condition of the heater, and observe the vapor pressure.

3. The vehicle of claim 2 , wherein the controller is programmed to,
in response to a difference between the vapor pressure and an ambient surrounding pressure being less than a second threshold, while the first valve is closed, the second valve is open, and the heater is deactivated, initiate the diagnostic test.

4. The vehicle of claim 3 , wherein the controller is programmed to,
in response to the difference between the vapor pressure and the ambient surrounding pressure being greater than the second threshold, while the first valve is closed, the second valve is open, and the heater is deactivated, forgo the diagnostic test.

5. The vehicle of claim 1 , wherein the controller is programmed to,
periodically initiate a second diagnostic test, the diagnostic test including, opening the first valve, closing the second valve, activating the heater, and sensing the vapor pressure within the fuel tank,
in response to the vapor pressure being greater than a second threshold during the second diagnostic test, output a signal indicating that the heater is operating properly, and
in response to the vapor pressure being less than the second threshold during the second diagnostic test, output a signal indicating that the heater is unable to turn on.

6. The vehicle of claim 5 , wherein the controller is programmed to,
in response to the vehicle being shutdown prior to initiating the second diagnostic test, open the first and second valves, and deactivate the heater,
in response to a predetermined period of time elapsing after the vehicle being shutdown and prior to initiating the diagnostic test, close the first valve, maintain an open condition of the second valve, maintain a deactivated condition of the heater, and sense the vapor pressure,
in response to a difference between the vapor pressure and an ambient surrounding pressure being less than a second threshold, while the first valve is closed, the second valve is open, and the heater is deactivated, initiate the second diagnostic test, and
in response to the difference between the vapor pressure and the ambient surrounding pressure being greater than the second threshold, while the first valve is closed, the second valve is open, and the heater is deactivated, forgo the second diagnostic test.

7. A vehicle comprising:
a fuel tank configured to store fuel;
a canister in fluid communication with the fuel tank and configured to receive evaporated fuel from the fuel tank, store the evaporated fuel via adsorption, and deliver the evaporated fuel to an engine via desorption;
a fuel tank vent valve disposed between the fuel tank and the canister, the fuel tank vent valve configured to facilitate fuel vapor flow from the fuel tank to the canister when open and to isolate the fuel tank from the canister when closed;
a canister vent valve disposed between the canister and ambient surroundings, the canister vent valve configured to facilitate fluid communication between the canister and the ambient surroundings when open and to isolate the canister from the ambient surroundings when closed;
a pressure sensor disposed between the canister and the fuel tank and configured to measure a pressure of the fuel vapor;
an electric heater disposed within the canister and configured to accelerate desorption; and
a controller programmed to,
periodically initiate a first diagnostic test, the first diagnostic test including,
opening the fuel tank vent valve,
closing the canister vent valve, and
activating the electric heater,

in response to the pressure sensor sensing an increase in the pressure of the fuel vapor exceeding a threshold during the first diagnostic test, output a signal indicating that the electric heater is operating properly,
in response to the pressure sensor sensing the increase in the pressure of the fuel vapor being less than the threshold during the first diagnostic test, output a signal indicating that the electric heater is unable to turn on,
periodically initiate a second diagnostic test, the second diagnostic test including,
opening the fuel tank vent valve,
closing the canister vent valve, and
deactivating the electric heater,

in response to the pressure sensor sensing the increase in the pressure of the fuel vapor being less than the second threshold during the second diagnostic test, output a signal indicating that the electric heater is operating properly, and
in response to the pressure sensor sensing the increase in the pressure of the fuel vapor exceeding a second threshold during the second diagnostic test, output a signal indicating that the electric heater is unable to turn off.

8. The vehicle of claim 7 , wherein the controller is programmed to,
in response to the vehicle being shutdown prior to initiating the first diagnostic test, open or maintain open conditions of the fuel tank vent valve and the canister vent valve, and deactivate or maintain a deactivated condition of the electric heater, and
in response to a predetermined period of time elapsing after the vehicle being shutdown and prior to initiating the first diagnostic test, close the fuel tank vent valve, maintain the open condition of the canister vent valve, maintain the deactivated condition of the electric heater, and sense the pressure of the fuel vapor via the pressure sensor.

9. The vehicle of claim 8 , wherein the controller is programmed to,
in response to the pressure sensor sensing a difference between the pressures of the fuel vapor and the ambient surroundings being less than a third threshold, while the fuel tank vent valve is closed, the canister vent valve is open, and the electric heater is deactivated, initiate the first diagnostic test.

10. The vehicle of claim 9 , wherein the controller is programmed to,
in response to the pressure sensor sensing the difference between the pressures of the fuel vapor and the ambient surroundings being greater than the third threshold, while the fuel tank vent valve is closed, the canister vent valve is open, and the electric heater is deactivated, forgo the first diagnostic test.

11. The vehicle of claim 7 , wherein the controller is programmed to, in response to initiating the first diagnostic test, activate the electric heater for a predetermined period of time p

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• F02M2025/0881

  with means to heat or cool the canister · CPC title

• F02M25/0854

  Details of the absorption canister · CPC title

• F02M25/0836 Primary

  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

• F02M25/0818 Primary

  having means for pressurising the evaporative emission space · CPC title

• F02M25/0809

  Judging failure of purge control system · CPC title