System and method for controlling fuel cell of vehicle

Patent metadata

Field	Value
Publication number	US-10074863-B2
Application number	US-201514833940-A
Country	US
Kind code	B2
Filing date	Aug 24, 2015
Priority date	Jan 19, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A system and method for controlling a fuel cell of a vehicle are provided. The method includes sensing a time point when pressure control is necessary by sensing whether an output of the fuel cell is additionally necessary or whether the fuel cell can be in a dry-out state. In response to sensing that the pressure control is necessary, a required valve opening degree of an air outlet is derived by substituting a target air pressure for a data map. A fuel cell air outlet valve is then adjusted based the derived valve opening degree of the air outlet.

First claim

What is claimed is:

1. A method for controlling a fuel cell of a vehicle, comprising:
determining, by a controller, whether a pressure control for pressing air discharged from an air supplier is necessary based on whether an output of the fuel cell is additionally necessary or whether the fuel cell is in a dry-out state;
when determined that the pressure control is necessary, deriving, by the controller, an opening degree of a valve required for the pressure control and adjusting the valve based on the derived opening degree of the valve;
calculating, by the controller, a pressure ratio obtained by calculating:
(current opening degree−first opening degree)/(second opening degree−first opening degree); and

increasing, by the controller, a target hydrogen pressure based on an increase of the calculated pressure ratio or an increase of a flow rate of the air discharged from the air supplier,
wherein the current opening degree is a valve opening degree at the current time, the first opening degree is an opening degree that is required when an air pressure is an atmospheric pressure, and the second opening degree is an opening degree at a time when the pressure control is completed.

2. The method of claim 1 , wherein the determination includes determining that the pressure control is necessary when an operation temperature of the fuel cell is equal to or greater than a reference temperature when the output of the fuel cell is equal to or greater than a reference output or if the fuel cell is in the dry-out state.

3. The method of claim 1 , further comprising:
determining, by the controller, whether an atmospheric pressure control for changing a pressure of air discharged from the air supplier to an atmospheric pressure is necessary when flooding occurs during a pressure operation for adjusting the valve with the opening degree of the valve required for the pressure control; and
deriving, by the controller, the opening degree of the valve required for the pressure control and adjusting the valve based on the derived opening degree of the valve in response to determining that the pressure control is necessary.

4. The method of claim 1 , further comprising:
selecting, by the controller, a target air pressure; and
deriving, by the controller, a valve opening degree command to follow the selected target air pressure.

5. The method of claim 4 , wherein a flow rate of the air that is discharged from the air supplier and the target air pressure respectively have values within preset limit regions with respect to the air flow rate and air pressure.

6. The method of claim 4 , wherein the derivation of a valve opening degree command includes deriving the valve opening degree command using an opening degree map in which the target air pressure and the valve opening degree to follow the target air pressure are pre-mapped.

7. The method of claim 6 , wherein in the opening degree map, the target air pressure and the valve opening degree to follow the target air pressure are differently pre-mapped based on the flow rate of the air that is discharged from the air supplier and an operation temperature of the fuel cell.

8. The method of claim 6 , wherein the opening degree is pre-mapped in which the opening degree during the pressure control is less than the opening degree during the atmospheric pressure control.

9. The method of claim 7 , wherein the opening degree map is pre-mapped to decrease a required valve opening degree as the operation temperature of the fuel cell is increased when the target air pressure is equal to the air flow rate.

10. The method of claim 6 , wherein the target air pressure includes a first air pressure in an atmospheric pressure state and a second air pressure in a pressure state, and the opening degree map is pre-mapped to adjust a required valve opening degree to be a first opening degree when the target air pressure is the first air pressure and the required valve opening degree to be a second opening degree when the target air pressure is the second air pressure.

11. The method of claim 10 , wherein the opening degree map is pre-mapped to decrease the required valve opening degree between the first opening degree and the second opening degree when the target air pressure is in a section in which the target air pressure is increased from the first air pressure to the second air pressure.

12. The method of claim 7 , wherein the opening degree map is pre-mapped to change a required valve opening degree with a hysteresis band based on a change of the flow rate of the air.

13. The method of claim 6 , wherein the opening degree map is pre-mapped to change a required valve opening degree in process of time when a maximum slew rate is limited.

14. The method of claim 1 , further comprising:
fixing, by the controller, a maximum value of a stoichiometric ratio (SR) to a minimum value when the pressure control is completed.

15. The method of claim 3 , further comprising:
increasing, by the controller, a maximum value of a stoichiometric ratio (SR) based on an increase of the opening degree of the valve during the atmospheric pressure control.

16. The method of claim 14 , wherein the fixing comprises adjusting the maximum value of the SR to gradually decrease the maximum value of the SR before the pressure control is completed with a slope and to reach the minimum value when the pressure control is completed.

17. The method of claim 16 , wherein the determination of a pressure control completion time is based on calculation of a pressure ratio obtained by calculating:
(current opening degree−first opening degree)/(second opening degree−first opening degree),

wherein the current opening degree is a valve opening degree at the current time, the first opening degree is an opening degree that is required when an air pressure is an atmospheric pressure, and the second opening degree is an opening degree at a time when the pressure control is completed.

18. The method of claim 17 , wherein the pressure ratio has a value between 0 and 1, the maximum value of the SR is in reverse proportion to an increase of the pressure ratio, and the maximum value of the SR is equal to the minimum value of the SR if the pressure ratio is 1.

19. The method of claim 1 ,
wherein the level of the target hydrogen pressure increased based on the increase of the flow rate of the air differs based on the pressure ratio.

20. The method of claim 1 , further comprising:
comparing, by the controller, the derived opening degree of the valve with a detected actual opening degree of the valve; and
limiting, by the controller, the output of the fuel cell when the derived opening degree of the valve is greater than the actual opening degree of the valve.

21. The method of claim 1 , further comprising:
comparing, by the controller, the derived opening degree of the valve with a detected actual opening degree of the valve; and
maximally increasing, by the controller, the opening degree of the valve when the derived opening degree of the valve is greater than the actual opening degree of the valve.

22. The method of claim 1 , further comprising:
comparing, by the controller, the derived opening degree of the valve with a detected actual opening degree of the valve; and
limiting, by the controller, a maximum revolutions per minute (RPM) of the air supplier when the derived opening degree of the valve is greater than the actual opening degree of the valve.

23. The method

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Kwon Sang Uk
• Lee Heon Joong
• Lee Nam Woo

Classifications

• H01M8/04104 Primary

  Regulation of differential pressures · CPC title

• H01M8/04992

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

• H01M2250/20

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

• H01M8/04619

  of fuel cell stacks · CPC title

• H01M8/04365

  of other components of a fuel cell or fuel cell stacks · CPC title