Operating load control for fuel cell power system in fuel cell vehicle

• US 7,059,436 B2
• Filed: 10/09/2001
• Issued: 06/13/2006
• Est. Priority Date: 10/31/2000
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iwasaki, Yasukazu
• Primary Examiner(s): RESTIFO, JEFFREY J
• Application Number:
  US10/069,499
• Publication Number:
  US 20020162694A1
• Time in Patent Office: 1,708 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.8, 429/23, 320/104, 701/22
• US Class Current: 429/430
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 8/04 Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A fuel cell vehicle drives a motor (9) with electric power from a fuel cell power system (100) comprising a fuel cell (4) which generates electricity using hydrogen and oxygen. A controller (10) calculates an electrical load demand required to run the vehicle. When this value is below a predetermined load, it performs constant load operation of the fuel cell power system (100), and when the predetermined load value is exceeded, it operates it under a load according to the electrical load demand. The demand for resolution and precision of the various sensors or flowrate control valves installed in the fuel cell power system and thereby suppressed, costs can be reduced, and fuel cost-performance is improved by continuing an efficient operating state.

Claims

1. A fuel cell vehicle, comprising:

a fuel cell power system which generates power using hydrogen and oxygen;

a motor for a vehicle drive which runs by receiving the power supplied from the fuel cell power system; and

a controller functioning to;

compute an electrical load demand required for running the vehicle,

operate the fuel cell power system under a constant load regardless of the electrical load demand, when the electrical load demand is smaller than a predetermined load, the predetermined load corresponding to the constant load and the constant load being larger than a load in an idle operation, and

operate the fuel cell power system under a load according to the electrical load demand, when the electrical load demand is larger than the predetermined load.

2. The fuel cell vehicle as defined in claim 1, wherein:

the electrical load demand is an instantaneous value of an electrical load required for running the vehicle.

3. The fuel cell vehicle as defined in claim 1, wherein:

the electrical load demand is a time average of an electrical load required for running the vehicle.

4. The fuel cell vehicle as defined in claim 3, wherein the time average of the electrical load demand is the average of the electrical load demand in a time interval shorter than the startup time of the fuel cell power system.

5. The fuel cell vehicle as defined in claim 1, wherein:

steady state operation under the predetermined load is included in the constant load operation.

6. The fuel cell vehicle as defined in claim 5, further comprising:

a battery which stores the power generated by the fuel cell power system and

a sensor which detects a charge state of the battery, wherein

the controller further functions to change over the operating state of the fuel cell power system from the steady state operation to the idle operation state, when the charge state of the battery reaches an predetermined upper limit.

7. The fuel cell vehicle as defined in claim 5, further comprising:

a battery which stores the power generated by the fuel cell power system, and

a sensor which detects a charge state of the battery, wherein

the controller further functions to change over the operating state of the fuel cell power system from the steady state operation to the stop state, when the charge state of the battery reaches a predetermined upper limit.

8. The fuel cell vehicle as defined in claim 1, wherein:

idle operation is included in the constant load operation.

9. The fuel cell vehicle as defined in claim 1, wherein the predetermined load is a load corresponding to the maximum efficiency operating point of the fuel cell power system.

10. The fuel cell vehicle as defined in claim 1, wherein the controller further functions to:

continuously operate the fuel cell power system so that the operating load of the fuel cell power system is the electrical load demand, when the electrical load demand is larger than the predetermined load.

11. The fuel cell vehicle as defined in claim 1, further comprising:

a battery which stores the power generated by the fuel cell power system, and

a sensor which detects a charge state of the battery, wherein the controller further functions to;

operate the fuel cell power system such that the battery is charged until the charge state of the battery reaches a predetermined upper limit, when the charge state of the battery reaches a predetermined lower limit, and

operate the fuel cell power system in the idle operation state until the charge state of the battery reaches the predetermined lower limit, when the charge state of the battery reaches the predetermined upper limit.

12. The fuel cell vehicle as defined in claim 1, further comprising:

a battery which stores the power generated by the fuel cell power system, and

a sensor which detects a charge state of the battery, wherein the controller further functions to;

operate the fuel cell power system such that the battery is charged until the charge state of the battery reaches a predetermined upper limit, when the charge state of the battery reaches a predetermined lower limit, and

stop the fuel cell power system until the charge state of the battery reaches the predetermined lower limit, when the charge state of the battery reaches the predetermined upper limit.

13. The fuel cell vehicle as defined in claim 1, further comprising:

a battery which stores the power generated by the fuel cell power system, and

a sensor which detects a charge state of the battery, wherein the controller further functions to compensate the predetermined load according to the charge state of the battery.

14. The fuel cell vehicle as defined in claim 1, wherein:

stop state is included in the constant load operation.

15. The fuel cell vehicle as defined in claim 1, further comprising:

a battery which stores the power generated by the fuel cell power system, wherein the controller further functions to;

continuously operate the fuel cell power system such that the operation load of the fuel cell power system is a value obtained by compensating the electrical load demand according to the charge state of the battery, when the electrical load demand is larger than the predetermined load.

16. A fuel cell vehicle, comprising:

a fuel cell power system which generates power using hydrogen and oxygen;

a motor for a vehicle drive which runs by receiving the power supplied from the fuel cell power system;

a battery which stores the power generated by the fuel cell power system;

a sensor which detects a charge state of the battery; and

a controller functioning to;

compute an electrical load demand required for running the vehicle,

operate the fuel cell power system under a constant load regardless of the electrical load demand, when the electrical load demand is smaller than a predetermined load,

operate the fuel cell power system under a load according to the electrical load demand, when the electrical load demand is larger than the predetermined load,

operate the fuel cell power system such that the battery is charged until the charge state of the battery reaches a predetermined upper limit, when the charge state of the battery reaches a predetermined lower limit, and

operate the fuel cell power system in the idle operation state until the charge state of the battery reaches the predetermined lower limit, when the charge state of the battery reaches the predetermined upper limit.

17. A fuel cell vehicle, comprising:

a fuel cell power system which generates power using hydrogen and oxygen;

a motor for a vehicle drive which runs by receiving the power supplied from the fuel cell power system;

a battery which stores the power generated by the fuel cell power system;

a sensor which detects a charge state of the battery, and

a controller functioning to;

compute an electrical load demand required for running the vehicle,

operate the fuel cell power system under a constant load regardless of the electrical load demand, when the electrical load demand is smaller than a predetermined load,

operate the fuel cell power system under a load according to the electrical load demand, when the electrical load demand is larger than the predetermined load,

operate the fuel cell power system such that the battery is charged until the charge state of the battery reaches a predetermined upper limit, when the charge state of the battery reaches a predetermined lower limit, and

stop the fuel cell power system until the charge state of the battery reaches the predetermined lower limit, when the charge state of the battery reaches the predetermined upper limit.