Cathode humidification unit adapting degradation factor

Patent metadata

Field	Value
Publication number	US-9502726-B2
Application number	US-201313939578-A
Country	US
Kind code	B2
Filing date	Jul 11, 2013
Priority date	Mar 14, 2013
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A method and an apparatus to adapt the performance of a cathode humidification unit as a membrane in a fuel cell stack degrades over time. An algorithm compares a sensed humidity profile of the fuel cell stack and model humidity profile of a cathode humidification unit model to calculate a new degradation factor. The cathode humidification unit model uses the degradation factor in the performance of the cathode humidification unit.

First claim

What is claimed is:

1. An apparatus for maintaining performance of a cathode humidification unit (CHU) within a fuel cell system, the fuel cell system comprising the CHU fluidly coupled to at least one valve and a fuel cell stack, the apparatus comprising:
a sensor coupled to the CHU; and
a controller electrically coupled to the sensor and the at least one valve, the controller comprising a processor and a computer readable medium containing computer readable and executable instructions which, when executed by the processor, cause the controller to automatically:
check if at least one enablement criteria is met,
determine if the sensor is functioning and valid based on a status of the fuel cell system,
sense a humidity of the CHU with the sensor,
determine a sensed humidity profile of the CHU using the sensed humidity from the sensor,
calculate a model humidity profile,
calculate an error value as a difference of the model humidity profile and the sensed humidity profile,
adjust a degradation factor using the error value if the at least one enablement criteria is met, and
adjust the at least one valve based on the degradation factor.

2. The apparatus of claim 1 , wherein the computer readable and executable instructions are executed by the processor to cause the controller to automatically calculate an average error value from an average of a plurality of error values stored in the computer readable medium and adjust the degradation factor using the average error value.

3. The apparatus of claim 2 , wherein the computer readable and executable instructions are executed by the processor to cause the controller to automatically calculate the error value only during an adaptation period.

4. The apparatus of claim 3 , wherein the adaptation period is a period of time the at least one enablement criteria is met.

5. The apparatus of claim 3 , wherein the error value is calculated only when a data accumulation timer is running.

6. The apparatus of claim 1 , wherein the computer readable and executable instructions are executed by the processor to cause the controller to automatically initialize the degradation factor to an initial set value in the computer-readable medium if the cathode humidification unit is new.

7. The apparatus of claim 1 , wherein the computer readable and executable instructions are executed by the processor to cause the controller to automatically indicate a need for service of the CHU when the error value is above an upper threshold or when the error value is below a lower threshold.

8. The apparatus of claim 1 , wherein the sensor is a relative humidity sensor or a high frequency resistance measurement.

9. A system for maintaining performance of a cathode humidification unit (CHU), the system comprising:
a fuel cell stack fluidly coupled to the CHU;
at least one valve configured to, when actuated, adjust a relative humidity of the CHU and the fuel cell stack;
a sensor coupled to the fuel cell stack, the CHU, or both, the sensor configured to sense humidity within the CHU; and
a controller electrically coupled to the sensor and the at least one valve, the controller comprising a processor and a computer-readable medium, the computer-readable medium containing computer readable and computer executable instructions that, when executed by the processor, cause the controller to automatically:
determine whether an enablement criteria is met,
determine whether the sensor is functioning and valid based on a status of the fuel cell stack,
sense, using the sensor, an amount of humidity within the fuel cell stack, the CHU, or both,
determine, using the amount of humidity, a sensed humidity profile of the CHU,
calculate, using a CHU model, a model humidity profile,
calculate, using a difference between the model humidity profile and the sensed humidity profile, an error value,
store, using the computer-readable medium, the error value to produce at least one stored error value,
adjust, using the at least one stored error value and if the enablement criteria is met, a degradation factor, and
actuate, based on the degradation factor, the at least one valve to adjust a relative humidity of the CHU and the fuel cell stack.

10. The system of claim 9 , wherein determination of the sensed humidity profile of the CHU, calculation of the model humidity profile, calculation of the difference between the model humidity profile and the sensed humidity profile, and storage of the error value occur a plurality of times prior to adjustment of the degradation factor, and wherein using the at least one stored error value includes averaging the at least one stored error value.

11. The system of claim 9 , wherein calculation of the error value and storage of the error value occur only during an adaptation period.

12. The system of claim 11 , wherein the adaptation period is a period of time when the enablement criteria is met.

13. The system of claim 11 , wherein calculation of the error value occurs only during a period when a data accumulation timer is running.

14. The system of claim 9 , wherein the computer readable and computer executable instructions, when executed by the processor, further cause the controller to automatically:
initialize, in response to the CHU being generally new, the degradation factor to an set value, the initialization occurring prior to the adjustment of the degradation factor.

15. The system of claim 9 , wherein the computer readable and computer executable instructions, when executed by the processor, further cause the controller to automatically:
indicate, in response to the error value being outside of a lower threshold and an upper threshold, a need for service of the CHU.

16. The system of claim 9 , wherein the sensor is one of a relative humidity sensor and a high-frequency resistance measurement sensor.

17. The system of claim 9 , wherein the computer readable and computer executable instructions, when executed by the processor, further cause the controller to automatically:
reset, in response to the error value being outside of a lower threshold and an upper threshold, the degradation factor.

18. The system of claim 9 , wherein the enablement criteria include a temperature of the fuel cell system, a specified mode, a diagnostic being active, a bleed event, or combinations thereof.

19. The system of claim 9 , wherein the computer readable and computer executable instructions, when executed by the processor, further cause the controller to automatically:
discard, in response to the error value being above an upper threshold, the error value such that adjustment of the degradation factor does not include using error values above the upper threshold.

20. The system of claim 9 , wherein the computer readable and computer executable instructions, when executed by the processor, further cause the controller to automatically:
discard, in response to the error value being below a lower threshold, the error value such that adjustment of the degradation factor does not include using error values below the lower threshold.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Nolan John P
• Folmsbee Daniel T
• Lebzelter Derek R
• Zhang Yan

Classifications

• H01M8/04507

  of cathode reactants at the inlet or inside the fuel cell · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M8/0432

  Temperature; Ambient temperature · CPC title

• H01M8/04126

  Humidifying · CPC title

• H01M8/04992 Primary

  characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence · CPC title