Controller for electric vehicle and electric vehicle using the same

• US 6,137,250 A
• Filed: 07/15/1998
• Issued: 10/24/2000
• Est. Priority Date: 07/16/1997
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kitada, Shinichirou, Kaneko, Yutarou, Asou, Takeshi, Hirano, Hiroyuki, Kikuchi, Toshio, Idoguchi, Ryuichi, Inada, Eiji
• Primary Examiner(s): Ip, Paul
• Assistant Examiner(s): Leykin, Rita
• Application Number:
  US09/115,635
• Time in Patent Office: 832 Days
• Field of Search: 318/139, 318/153, 318/140, 318/375, 318/376, 364/424.026, 180/65.2, 180/65.1-65.4, 180/65.6-65.8, 320/2, 320/5, 320/61, 701/202
• US Class Current: 318/376
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 2240/16 longitudinal
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/106 Rate of change
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor

Abstract

There is disclosed a controller for an electric vehicle that allows for securing a sufficient battery capacity and is able to substantially avoid giving an uncomfortable feeling to the crew even if an engine for power generation is started. The controller comprises a power generation control unit which makes a generator of the electric vehicle generate electric power by starting a generator-driving engine of the electric vehicle in the case that an SOC (state of charge) of a battery of the electric vehicle is equal to or less than a first value, and further makes the generator generate the electric power by starting the generator-driving engine in the case that the SOC of the battery is equal to or less than a second value larger than the first value and a predetermined condition is satisfied. Further, an electric vehicle provided with such a controller is also disclosed.

Claims

1. An electric vehicle, comprising:

an electric motor driving said electric vehicle;

a battery storing electric power to be supplied to said electric motor;

a generator to generate electric power so as to supply said electric power generated by said generator to said electric motor and/or said battery;

an engine making said generator generate said electric power;

a first sensor detecting a state of charge (SOC) of said battery;

a second sensor detecting an operative condition of said electric vehicle; and

a controller enabling said generator to generate said electric power by starting said engine when said SOC detected by said first sensor is equal to or less than a first value, and enabling said generator to generate said electric power by starting said engine when said SOC detected by said first sensor is equal to or less than a second value larger than said first value and said operative condition of said electric vehicle is detected by said second sensor, while not starting said engine to enable said generator to generate said electric power when said SOC detected by said first sensor is equal to or less than said second value but said operative condition of said electric vehicle is not detected by said second sensor,

wherein there is a region in which said controller does not start said engine to enable said generator to generate said electric power when said SOC detected by said first sensor is more than said first value and equal to or less than said second value after said controller does not start said engine to enable said generator to generate said electric power when said SOC detected by said first sensor is equal to or more than said second value but said operative condition of said electric vehicle is not detected by said second sensor.

2. An electric vehicle according to claim 1, wherein said operative condition of said electric vehicle includes said accelerator stroke length of said electric vehicle being at or above a predetermined value.

3. An electric vehicle according to claim 1, wherein said operative condition of said electric vehicle includes said accelerator stroke speed of said electric vehicle being at or above a predetermined value.

4. An electric vehicle according to claim 1, wherein said operative condition of said electric vehicle includes velocity of said electric vehicle being at or above a predetermined value.

5. An electric vehicle according to claim 1, wherein said operative condition of said electric vehicle includes an acceleration of said electric vehicle being at or above a predetermined value.

6. An electric vehicle according to claim 1, wherein said operative condition of said electric vehicle includes a high load being applied to said electric vehicle.

7. An electric vehicle according to claim 1, wherein said second value is located within a range of above a normal power generation starting SOC and below a normal power generation completion SOC by a predetermined value.

8. An electric vehicle according to claim 1, wherein said electric vehicle is a series hybrid electric vehicle.

10. An electric vehicle according to claim 1, wherein said first value is equal to 80% of SOC and wherein said second value is equal to 40% of SOC.

9. A controller for an electric vehicle, said electric vehicle being provided with an electric motor driving said electric vehicle, a battery storing electric power, a generator generating electric power so as to supply said electric power generated by said generator to said electric motor and/or said battery, and an engine capable of making said generator generate said electric power, comprising:

a power generation control means for enabling said generator to generate said electric power by starting said engine when a state of charge (SOC) of said battery is equal to or less than a first value, and enabling said generator to generate said electric power by starting said engine when said SOC is equal to or less than a second value larger than said first value and an operative condition of said electric vehicle is satisfied, while not starting said engine to enable said generator to generate said electric power when said SOC is equal to or less than said second value but said operative condition of said electric vehicle is not satisfied,

wherein there is a region in which said power generation control means does not start said engine to enable said generator to generate said electric power when said SOC is more than said first value and equal to or less than said second value after said power generation control means does not start said engine to enable said generator to generate said electric power when said SOC is equal to or more than said second value but said operative condition of said electric vehicle is not satisfied.

11. A controller for an electric vehicle according to claim 9, wherein said first value is equal to 80% of SOC and wherein said second value is equal to 40% of SOC.

12. A controller for an electric vehicle according to claim 9, wherein said first value is equal to 80% of SOC and wherein said second value is equal to 40% of SOC.

13. A controller for an electric vehicle, said electric vehicle being provided with an electric motor driving said electric vehicle, a battery storing electric power, a generator generating electric power so as to supply said electric power generated by said generator to said electric motor and/or said battery, and an engine capable of making said generator generate said electric power, comprising:

a power generation control unit enabling said generator to generate said electric power by starting said engine when a state of charge (SOC) of said battery is equal to or less than a first value, and enabling said generator to generate said electric power by starting said engine when said SOC is equal to or less than a second value larger than said first value and an operative condition of said electric vehicle is satisfied, while not starting said engine to enable said generator to generate said electric power when said SOC is equal to or less than said second value but said operative condition of said electric vehicle is not satisfied,

wherein there is a region in which said power generation control unit does not start said engine to enable said generator to generate said electric power when said SOC is more than said first value and equal to or less than said second value after said power generation control unit does not start said engine to enable said generator to generate said electric power when said SOC is equal to or more than said second value but said operative condition of said electric vehicle is not satisfied.

14. A controller according to claim 13, wherein said operative condition is detected in correspondence with velocity of said electric vehicle and determination is performed whether said velocity is equal to or more than a predetermined value or not.

15. A controller according to claim 13, wherein said operative condition is detected in correspondence with acceleration of said electric vehicle and determination is performed whether said acceleration is equal to or more than a predetermined value or not.

16. A controller according to claim 13, wherein said operative condition is detected in correspondence with a state where said electric vehicle is going up a hill and determination is performed whether said vehicle is going up said hill or not.

17. A controller according to claim 15, wherein said operative condition is detected in correspondence with an accelerator stroke length of said electric vehicle.

18. A controller according to claim 16, wherein said operative condition is detected in correspondence with an accelerator stroke length of said electric vehicle.

19. A controller according to claim 15, wherein said operative condition is detected in correspondence with an accelerator stroke speed of said electric vehicle.

20. A controller according to claim 16, wherein said operative condition is detected in correspondence with an accelerator stroke speed of said electric vehicle.

21. A controller according to claim 15, wherein said operative condition is detected in correspondence with velocity change of said electric vehicle.

22. A controller according to claim 16, wherein said operative condition is detected in correspondence with velocity change of said electric vehicle.

23. A controller according to claim 14, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.

24. A controller according to claim 15, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.

25. A controller according to claim 16, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.

26. A controller according claim 17, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.

27. A controller according to claim 18, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.

28. A controller according to claim 19, wherein said power generation control unit prohibits a start of said engine, even if said operative condition is satisfied, when said SOC of said battery is more than said second value.