Vehicle fuel cell purging system

Patent metadata

Field	Value
Publication number	US-2019081337-A1
Application number	US-201715701970-A
Country	US
Kind code	A1
Filing date	Sep 12, 2017
Priority date	Sep 12, 2017
Publication date	Mar 14, 2019
Grant date	—

Abstract

A vehicle includes a fuel cell having a stack for generating power and a controller. The controller is programmed to, in response to a fuel cell temperature decreasing to less than a temperature threshold after a shutdown, initiate a primary purge of the stack and terminate the primary purge at a predetermined anode pressure.

First claim

What is claimed is:

1 . A vehicle comprising:
a fuel cell having a stack for generating power; and a controller programmed to, in response to a fuel cell temperature decreasing to less than a temperature threshold after a shutdown, initiate a primary purge of the stack and terminate the primary purge at a predetermined anode pressure.

2 . The vehicle of claim 1 , wherein the primary purge includes flowing hydrogen gas through an anode of the fuel cell and flowing air through a cathode of the fuel cell.

3 . The vehicle of claim 1 , wherein the controller is programmed to, in response to a cross-pressure between an anode of fuel cell and a cathode of the fuel cell decreasing to less than a pressure threshold after termination of the primary purge, initiate a secondary purge of the stack.

4 . The vehicle of claim 3 , wherein the secondary purge includes flowing hydrogen gas through the anode and flowing air through the cathode.

5 . The vehicle of claim 3 , wherein the secondary purge includes flowing air through the cathode alone.

6 . The vehicle of claim 5 , wherein the anode is open to atmosphere during the secondary purge.

7 . The vehicle of claim 5 , wherein the anode is closed to atmosphere during the secondary purge.

8 . The vehicle of claim 5 , wherein the controller is programmed to, in response to termination of the secondary purge, initiate a tertiary purge of the stack.

9 . The vehicle of claim 8 , wherein the tertiary purge includes flowing hydrogen gas through the anode and flowing air through the cathode.

10 . The vehicle of claim 3 , wherein the secondary purge includes flowing hydrogen gas through the anode alone.

11 . The vehicle of claim 3 , wherein the secondary purge includes flowing air through the anode and the cathode.

12 . A vehicle comprising:
a fuel cell having a stack; and a controller programmed to,
responsive to a fuel cell temperature decreasing to less than a temperature threshold after a shutdown, initiate a primary purge of the stack, and
responsive to a cross-pressure between an anode and a cathode of the stack decreasing to less than a pressure threshold after termination of the primary purge, initiate a secondary purge of the stack.

13 . The vehicle of claim 12 , wherein the primary purge includes flowing air through the cathode alone.

14 . The vehicle of claim 13 , wherein the anode is open to atmosphere during the primary purge.

15 . The vehicle of claim 13 , wherein the secondary purge includes flowing hydrogen gas through the anode and flowing air through the cathode.

16 . A fuel cell purging method comprising:
purging a fuel cell stack after a shutdown in response to,
a difference between anode and cathode pressures of the stack decreasing to a pressure threshold, or
a fuel cell temperature decreasing to an above-freezing threshold while the anode pressure is less than the cathode pressure and the difference is greater than the pressure threshold.

17 . The method of claim 16 further comprising:
purging the stack in response to the fuel cell temperature decreasing to freezing while the anode pressure is less than the cathode pressure, and terminating the purge when the difference has obtained a predetermined value where the anode pressure is greater than cathode pressure.

18 . The method of claim 16 , wherein the purge includes flowing hydrogen gas through an anode of the fuel cell and flowing air through a cathode of the fuel cell at initial rates.

19 . The method of claim 18 further comprising:
in response to an elapse of time during the purge,
maintaining the initial flow rate of hydrogen through the anode,
decreasing airflow through the cathode to less than the initial flow rate, and
applying an electric load to the fuel cell.

20 . The method of claim 16 , wherein the purge includes flowing hydrogen gas through an anode of the fuel cell alone.

Assignees

• Ford Global Tech Llc

Inventors

• Riley Matthew
• Mathie Craig Michael
• Wujcik Kevin
• Sanderson Jr William Frederick

Classifications

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/04303 Primary

  applied during shut-down · CPC title

• H01M8/04701

  Temperature · CPC title

• H01M8/04231

  Purging of the reactants · CPC title