Control method for fuel cell system to prevent freezing in air exhaust system

Patent metadata

Field	Value
Publication number	US-11289723-B2
Application number	US-201916405604-A
Country	US
Kind code	B2
Filing date	May 7, 2019
Priority date	Dec 12, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

A control method for a fuel cell system is provided to prevent freezing in an air exhaust system of the fuel cell system. The method prevents freezing in the exhaust system by specifying a vehicle condition in which possibility of freezing is high and operating the fuel cell system based on different vehicle-specific standards. The performs air supercharging control based on an ambient temperature and a temperature of cooling water, air supercharging control by applying weights based on inclinations of a vehicle, and a forced heating logic using a COD heater.

First claim

What is claimed is:

1. A control method for a fuel cell system, the fuel cell system comprising an air supply unit including an air blower and an air inlet shut-off valve which are disposed on a front end of an air electrode of a fuel cell stack, an air outlet shut-off valve and an air pressure control valve which are disposed sequentially on a rear end of the air electrode to discharge air, the control method comprising:
performing, by a controller having a processor and a memory, air supercharging control to increase a flow rate of air entering a fuel cell stack through the air blower and the air inlet shut-off valve, when an ambient temperature is less than a predetermined reference temperature and a temperature of cooling water of a fuel cell stack at an outlet of the fuel cell stack is within a predetermined range of temperature of supercharged air in a state in which the fuel cell stack is in a power generation state,
wherein the air supercharging control includes supplying an amount of air greater than a predetermined minimum flow rate of air to prevent freezing in an air exhaust system, and the predetermined minimum flow rate of air indicates a lowest limit at which produced water in the fuel cell stack is discharged.

2. The control method according to claim 1 , wherein, in the air supercharging control, an amount of supercharged air is determined based on the ambient temperature and the temperature of cooling water of the fuel cell stack leaving the outlet of the fuel cell stack.

3. The control method according to claim 1 , wherein the air supercharging control is performed when the ambient temperature is less than about 0° C.

4. The control method according to claim 1 , wherein the air supercharging control increases the flow rate of air entering the fuel cell stack by increasing a number of revolutions of an air blower.

5. The control method according to claim 1 , further comprising:
determining, by the controller, an inclination of the vehicle; and
determining, by the controller, an amount of supercharged air by applying a weight based on the inclination of the vehicle when the inclination of the vehicle is greater than an inclination threshold value.

6. The control method according to claim 1 , further comprising:
operating, by the controller, a cathode oxygen depletion heater when a state, in which an amount of power consumed by air conditioning for controlling a temperature of a passenger compartment of the vehicle is less than a predetermined reference value, the ambient temperature is less than a predetermined first temperature, and the temperature of cooling water of the fuel cell stack is less than a predetermined second temperature, is maintained for a predetermined first period of time.

7. The control method according to claim 6 , wherein operating the cathode oxygen depletion heater includes:
operating, by the controller, a cooling water pump at a predetermined reference number of revolutions or greater; and
operating, by the controller, a cooling water bypass valve within a predetermined opening degree.

8. The control method according to claim 7 , wherein the opening degree of the cooling water bypass valve is adjusted to be within a range from about 40° to 50°.

9. The control method according to claim 6 , further comprising:
turning off, by the controller, the cathode oxygen depletion heater, when the temperature of cooling water of the fuel cell stack at the outlet of the fuel cell stack is maintained at a temperature greater than a predetermined third temperature for a predetermined second period of time.

10. The control method according to claim 6 , further comprising:
turning off, by the controller, the cathode oxygen depletion heater when current output from the fuel cell stack is equal to or greater than predetermined reference current.

11. The control method according to claim 6 , further comprising:
turning off, by the controller, the cathode oxygen depletion heater when the cathode oxygen depletion heater is determined to be overheated as a result of measurement of a temperature within the cathode oxygen depletion heater.

12. The control method according to claim 6 , further comprising:
turning off, by the controller, the cathode oxygen depletion heater when the temperature of cooling water of the fuel cell stack is equal to or greater than a predetermined fourth temperature or a stack cell voltage difference is equal to or greater than a predetermined cell difference threshold value.

13. The control method according to claim 1 , further comprising:
shutting down, by the controller, the fuel cell system when the ambient temperature is less than a predetermined fifth temperature, when abnormality in the flow rate of air or the opening degree of the air pressure control value occurs and a reverse voltage state of the fuel cell stack continues for a predetermined third period of time or longer, to prevent the fuel cell stack from being damaged.

14. The control method according to claim 1 , wherein the fifth temperature is about 0° C., and generation of a reverse voltage is determined based on whether a minimum value of stack cell voltages is less than 0.

15. The control method of claim 1 , wherein the air supercharging control is performed when the vehicle is in an idling state after being started.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Jeon Kang Sik
• Jang Jae Hun
• Yang Sung Ho
• Cho Sung Mun

Classifications

• Y02T10/72

  Electric energy management in electromobility · CPC title

• H01M8/04228

  during shut-down · CPC title

• B60L1/003

  to auxiliary motors, e.g. for pumps, compressors · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• Y02T90/16

  Information or communication technologies improving the operation of electric vehicles · CPC title