Drive state shift control apparatus and method for vehicle

• US 20070278022A1
• Filed: 04/30/2007
• Published: 12/06/2007
• Est. Priority Date: 05/02/2006
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tanishima, Kaori
• Granted Patent: US 7,954,581 B2
• Time in Patent Office: Days
• US Class Current: 180/65.285
• CPC Class Codes: B60K 6/383 One-way clutches or freewheel devices
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/115 with planetary gears
• 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 20/40 : Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2510/0241 : Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2510/0638 : Engine speed
• CPC Class Codes: B60W 2510/081 : Speed
• CPC Class Codes: B60W 2510/1015 : Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 : Output speed
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 30/19 : Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• 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 903/913 : One way
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A drive state shift control apparatus and method switches a hybrid drive (HEV) mode to an electric drive (EV) mode without engine stoppage shock or eliminates gearshifting shock in an electric vehicle. In response to a decrease in accelerator opening APO, a request for fourth-to-fifth upshift is issued, then request for HEV-to-EV mode shift is issued. At the time of the upshift, a direct clutch D/C is disengaged. At a first time interval after the mode shift is issued, a first clutch is disengaged. At a second time interval after the mode shift is issued, the engine begins to stop and the rotational speed of the motor-generator is controlled so that the speed falls to a predetermined rotational speed close to an after-gearshift rotational speed within a target shifting time interval. When the rotational speed reaches the predetermined rotational speed, a front brake Fr/B is engaged to perform a fourth-to-fifth upshift, and the torque of the motor is controlled so as to engage the one-way clutch smoothly.

Claims

1. A drive state shift control apparatus for a vehicle, comprising:

a motor-generator;

a unidirectional engagement element disposed between the motor-generator and the driving wheel configured for automatic engagement in response to driving torque in one direction; and

a controller operable to;

control a rotational speed of the motor-generator so that a rotational speed of an upstream side of the unidirectional engagement element in a direction of driving power transmission substantially conforms to a rotational speed of a downstream side thereof when the unidirectional engagement element is engaged in response to a shift in a driving power transmission path.

2. The apparatus according to claim 1, further comprising:

a clutch disposed between the motor-generator and a driving wheel for engagement and disengagement; and

wherein the controller is further operable to;

shift the clutch into a disengaged state from an engaged state transmitting a driving torque; and

control the rotational speed of the motor-generator so that the rotational speed of the upstream side of the unidirectional engagement element in the direction of driving power transmission substantially conforms to the rotational speed of a downstream side thereof when the unidirectional engagement element is engaged in response to the shift in a driving power transmission path after the clutch is shifted into the disengaged state.

3. The apparatus according to claim 2 wherein the controller is further operable to shift the clutch into the disengaged state from the engaged state responsive to an upshift at a time of a release of an accelerator pedal.

4. The apparatus according to claim 1 wherein the unidirectional engagement element is a one-way clutch.

5. The apparatus according to claim 1 wherein the rotational speed of the upstream side of the unidirectional engagement element in the direction of driving power transmission substantially conforms to the rotational speed of the downstream side thereof when a difference between the rotational speeds is ±

α

wherein a is a predetermined number greater than zero; and

wherein the controller is further operable to;

gradually control the difference toward zero.

6. The apparatus according to claim 5 wherein the controller is further operable to gradually control the difference toward zero by controlling an output torque of the motor-generator to conform to a requested vehicle driving force according to a vehicle operating state.

7. The apparatus according to claim 5 wherein the controller is further operable to gradually control the difference toward zero by using a rotational speed control to control the difference to change to zero at a predetermined gradient.

8. The apparatus according to claim 5, further comprising:

an engine; and

a transmission in tandem with the engine and the motor-generator; and

a first clutch between the engine and the motor-generator, wherein the shift in driving power transmission path is a shift from a hybrid drive in which the first clutch is engaged to an electric drive in which the first clutch is disengaged.

9. The apparatus according to claim 5 wherein the driving torque in the one direction is a driving torque in a direction to rotate the motor-generator by the driving wheel.

10. The apparatus according to claim 5, further comprising:

an engine; and

a transmission in tandem with the engine and the motor-generator; and

wherein the unidirectional engagement element is located within the transmission.

11. The apparatus according to claim 10, further comprising:

a first clutch between the engine and the motor-generator, wherein the shift in driving power transmission path is a shift from a hybrid drive in which the first clutch is engaged to an electric drive in which the first clutch is disengaged.

12. The apparatus according to claim 10 wherein the driving torque in the one direction is a driving torque in a direction to rotate the motor-generator by the driving wheel.

13. The apparatus according to claim 1, further comprising:

an engine; and

a transmission in tandem with the engine and the motor-generator; and

a first clutch between the engine and the motor-generator, wherein the shift in driving power transmission path is a shift from a hybrid drive in which the first clutch is engaged to an electric drive in which the first clutch is disengaged.

14. The apparatus according to claim 13 wherein the unidirectional engagement element is within the transmission.

15. The apparatus according to claim 13 wherein the driving torque in the one direction is a driving torque in a direction to rotate the motor-generator by the driving wheel.

16. The apparatus according to claim 13, further comprising:

a second clutch disposed between the motor-generator and the driving wheel; and

wherein the controller is further operable to;

initiate disengagement of the second clutch after receiving an up-shift command;

initiate disengagement of the first clutch after receiving an engine stop command;

carry out the engine stop command in a first time interval while starting the control of the rotational speed of the motor-generator and completing disengagement of second clutch; and

begin control of a motor torque of the motor-generator once a difference between the rotational speed of the upstream side of the unidirectional engagement element in the direction of driving power transmission and the rotational speed of the downstream side thereof is ±

α

wherein α

is a predetermined number greater than zero to compensate for an estimated engine torque after the first clutch begins to slip and to compensate for torque capacity of the first clutch until the first clutch is disengaged.

17. The apparatus according to claim 16 wherein the engine stop command is due to a cut in a fuel supply.

18. A controller for a drive state shift control apparatus for a vehicle, the vehicle including a motor-generator and a unidirectional engagement element disposed between the motor-generator and the driving wheel configured for automatic engagement in response to driving torque in one direction, the controller comprising:

means for shifting a driving power transmission path; and

means for controlling a rotational speed of the motor-generator so that a rotational speed of an upstream side of the unidirectional engagement element in a direction of driving power transmission substantially conforms to a rotational speed of a downstream side thereof when the unidirectional engagement element is engaged in response to the shift in the driving power transmission path.

19. A drive state shift control method for a vehicle, the vehicle including a motor-generator and a unidirectional engagement element disposed between the motor-generator and the driving wheel configured for automatic engagement in response to driving torque in one direction, the method comprising:

shifting a driving power transmission path; and

controlling a rotational speed of the motor-generator so that a rotational speed of an upstream side of the unidirectional engagement element in a direction of driving power transmission substantially conforms to a rotational speed of a downstream side thereof when the unidirectional engagement element is engaged in response to shifting the driving power transmission path.

20. The method according to claim 19 wherein the rotational speed of the upstream side of the unidirectional engagement element in the direction of driving power transmission substantially conforms to the rotational speed of the downstream side thereof when a difference between the rotational speeds is ±

α

wherein α

is a predetermined number greater than zero; and

further comprising;

gradually controlling the difference toward zero.

21. The method according to claim 20 wherein gradually controlling the difference toward zero further comprises controlling an output torque of the motor-generator to conform to a requested vehicle driving force according to a vehicle operating state.