Drive control device for hybrid vehicle

• US 7,055,636 B2
• Filed: 04/21/2004
• Issued: 06/06/2006
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iwano, Hiroshi, Komiyama, Susumu, Inoue, Hideaki, Yamaguchi, Ichiro, Negome, Taketora
• Primary Examiner(s): Ellis, Christopher P.
• Assistant Examiner(s): WALTERS, JOHN DANIEL
• Application Number:
  US10/828,288
• Publication Number:
  US 20040251065A1
• Time in Patent Office: 776 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.4
• US Class Current: 180/65.23
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• 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 10/10 including control of change-speed gearings
• 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 2510/0614 Position of fuel or air injector
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A target driving power is calculated in accordance with the operating condition, a fuel consumption rate per power unit is calculated at all the possible operating points of an engine (1) and a drive motor (5) to realize the target driving power, a target fuel consumption rate is set on the basis of the operating condition, and an operating point of the engine (1) and drive motor (5) at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is searched. When an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, the fuel consumption rate relating to driving power is corrected with only the fuel consumption rate relating to electric power for charging a battery device set at a predetermined value which is smaller than the actual fuel consumption rate, an operating point at which the fuel consumption rate relating to driving power reaches a minimum is selected, and the engine (1) and drive motor (5) are controlled to achieve the selected operating point.

Claims

1. A parallel hybrid vehicle comprising:

an engine and a drive motor capable of transmitting power to an output shaft;

a transmission interposed between the output shaft and the engine;

a battery device electrically connected to the drive motor; and

a controller configured to;

calculate a target driving power in accordance with an operating condition of the vehicle;

calculate a fuel consumption rate per power unit at all possible operating points of the engine and drive motor to realize the target driving power;

set a target fuel consumption rate on a basis of the vehicle operating condition;

search for an operating point of the engine and drive motor at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, control the engine and drive motor to achieve the operating point; and

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, correct the fuel consumption rate relating to driving power with only the fuel consumption rate relating to electric power for charging the battery device set at a predetermined value which is smaller than an actual fuel consumption rate, select an operating point at which the fuel consumption rate relating to driving power reaches a minimum, and control the engine and drive motor to achieve the selected operating point.

2. The vehicle as defined in claim 1, wherein the controller is further configured to stop the engine and drive the vehicle using the drive motor alone when the fuel consumption rate at the selected operating point is larger than the fuel consumption rate when the vehicle is run by the drive motor alone.

3. The vehicle as defined in claim 1, wherein the predetermined value is larger than the target fuel consumption rate.

4. The vehicle as defined in claim 1, wherein the predetermined value is equal to the target fuel consumption rate.

5. The vehicle as defined in claim 1, wherein the controller is further configured to reduce the target fuel consumption rate as storage amount of the battery device increases.

6. A parallel hybrid vehicle comprising:

a transmission to which an engine and a motor generator are connected;

a drive motor connected to an output shaft of the transmission or a drive shaft of the vehicle;

a battery device which is electrically connected to the drive motor and the motor generator; and

a controller configured to;

calculate a target driving power in accordance with an operating condition of the vehicle;

calculate a fuel consumption rate per power unit at all possible operating points of the engine, motor generator, and drive motor to realize the target driving power;

set a target fuel consumption rate on a basis of the vehicle operating condition;

search for an operating point of the engine, motor generator, and drive motor at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, control the engine, motor generator, and drive motor to achieve the operating point; and

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, correct the fuel consumption rate relating to driving power with only the fuel consumption rate relating to electric power for charging the battery device set at a predetermined value which is smaller than an actual fuel consumption rate, select an operating point at which the fuel consumption rate relating to driving power reaches a minimum, and control the engine, motor generator, and drive motor to achieve the selected operating point.

7. The vehicle as defined in claim 6, wherein the controller is further configured to stop the engine and drive the vehicle using the drive motor alone when the fuel consumption rate at the selected operating point is larger than the fuel consumption rate when the vehicle is run by the drive motor alone.

8. The vehicle as defined in claim 6, wherein the transmission is a planetary gear set comprising a sun gear, a carrier, and a ring gear, and

the engine, motor generator, and drive motor are connected to the sun gear, carrier, and ring gear respectively.

9. The vehicle as defined in claim 6, wherein the predetermined value is larger than the target fuel consumption rate.

10. The vehicle as defined in claim 6, wherein the predetermined value is equal to the target fuel consumption rate.

11. The vehicle as defined in claim 6, wherein the controller is further configured to reduce the target fuel consumption rate as storage amount of the battery device increases.

12. A parallel hybrid vehicle comprising:

a motor generator connected to an engine;

a battery device for storing electric power generated by the motor generator; and

a controller configured to;

calculate a fuel consumption rate per charging power unit at all possible operating points of the engine and motor generator when the vehicle is stationary;

set a target fuel consumption rate on a basis of an operating condition of the vehicle;

search for an operating point of the engine and motor generator at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, control the engine and motor generator to achieve the operating point; and

when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, determine a fuel consumption rate for realizing each operating point with the fuel consumption rate relating to the charging power at each operating point set at a predetermined value which is smaller than an actual fuel consumption rate, select an operating point at which the fuel consumption rate reaches a minimum, and control the engine and motor generator to achieve the selected operating point.

13. The vehicle as defined in claim 12, wherein the predetermined value is larger than the target fuel consumption rate.

14. The vehicle as defined in claim 12, wherein the predetermined value is equal to the target fuel consumption rate.

15. The vehicle as defined in claim 12, wherein the controller is further configured to reduce the target fuel consumption rate as storage amount of the battery device increases.

16. A parallel hybrid vehicle comprising:

an engine and a drive motor capable of transmitting power to an output shaft;

a transmission interposed between the output shaft and the engine;

a battery device electrically connected to the drive motor;

means for calculating a target driving power in accordance with an operating condition of the vehicle;

means for calculating a fuel consumption rate per power unit at all possible operating points of the engine and drive motor to realize the target driving power;

means for setting a target fuel consumption rate on a basis of the vehicle operating condition;

means for searching for an operating point of the engine and drive motor at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, controlling the engine and drive motor to achieve the operating point; and

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, correcting the fuel consumption rate relating to driving power with only the fuel consumption rate relating to electric power for charging the battery device set at a predetermined value which is smaller than an actual fuel consumption rate, selecting an operating point at which the fuel consumption rate relating to driving power reaches a minimum, and controlling the engine and drive motor to achieve the selected operating point.

17. A parallel hybrid vehicle comprising:

a transmission to which an engine and a motor generator are connected;

a drive motor connected to an output shaft of the transmission or a drive shaft of the vehicle;

a battery device which is electrically connected to the drive motor and the motor generator;

means for calculating a target driving power in accordance with an operating condition of the vehicle;

means for calculating a fuel consumption rate per power unit at all possible operating points of the engine, motor generator, and drive motor to realize the target driving power;

means for setting a target fuel consumption rate on a basis of the vehicle operating condition;

means for searching for an operating point of the engine, motor generator, and drive motor at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, controlling the engine, motor generator, and drive motor to achieve the operating point; and

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, correcting the fuel consumption rate relating to driving power with only the fuel consumption rate relating to electric power for charging the battery device set at a predetermined value which is smaller than an actual fuel consumption rate, selecting an operating point at which the fuel consumption rate relating to driving power reaches a minimum, and controlling the engine, motor generator, and drive motor to achieve the selected operating point.

18. A parallel hybrid vehicle comprising:

a motor generator connected to an engine;

a battery device for storing electric power generated by the motor generator;

means for calculating a fuel consumption rate per charging power unit at all possible operating points of the engine and motor generator when the vehicle is stationary;

means for setting a target fuel consumption rate on a basis of an operating condition of the vehicle;

means for searching for an operating point of the engine and motor generator at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized;

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized has been found, controlling the engine and motor generator to achieve the operating point; and

means for, when an operating point at which a fuel consumption rate that is equal to the target fuel consumption rate can be realized is not found, determining a fuel consumption rate for realizing each operating point with the fuel consumption rate relating to the charging power at each operating point set at a predetermined value which is smaller than an actual fuel consumption rate, selecting an operating point at which the fuel consumption rate reaches a minimum, and controlling the engine and motor generator to achieve the selected operating point.