HYBRID VEHICLE ENGINE START CONTROL DEVICE

• US 20130297128A1
• Filed: 10/03/2011
• Published: 11/07/2013
• Est. Priority Date: 10/21/2010
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Takamura, Yutaka, Yamamura, Yoshinori, Ashizawa, Hiroyuki, Amemiya, Jun
• Granted Patent: US 9,267,481 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• 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 2240/507 Operating parameters
• 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: B60W 10/02 including control of driveline clutches
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/20 Control strategies involving selection of hybrid configuration, e.g. selection between series or parallel configuration
• 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 2710/021 Clutch engagement state
• CPC Class Codes: B60W 2710/027 Clutch torque
• CPC Class Codes: B60W 30/192 : Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: F02N 11/0814 : comprising means for controlling automatic idle-start-stop
• CPC Class Codes: Y02T 10/40 : Engine management systems
• 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 903/902 : Prime movers comprising electrical and internal combustion motors

Abstract

When there is a requirement on switching from the electrically driven drive mode to the hybrid drive mode by changing an accelerator position opening, the torque capacity is generated for the first clutch to start the engine. However, as torque capacity is at β1, the engine rotational speed is quickly increased to the high-speed region free of the influence of the compressive reactive force of the engine; once the engine rotational speed becomes the high-speed region, the engine rotational speed is decreased as torque capacity and is at β2. Consequently, it is possible to quickly pass through the low engine rotational speed region as the engine rotational speed torque is increased under the influence of the compressive reactive force, and avoiding the poor acceleration, as can be seen from the smooth variation of the time sequence increase of the transmission output rotational speed as indicated by β3, is possible.

Claims

1. An engine start control system of a hybrid vehicle, the hybrid vehicle comprising an engine and an electrically driven motor as power sources, a first clutch is provided between the engine and the electrically driven motor for changing transmission torque capacity, and a second clutch is provided between the electrically driven motor and the drive wheels for a change in the transmission torque capacity;

at least one controller programmed to select an electrically driven running mode by shutting down the engine, releasing the first clutch and, at the same time, engaging the second clutch, so that only power from the electrically driven motor is being used, and to select the hybrid running mode is possible by engaging both the first clutch and the second clutch, so that the power from the engine and the electrically driven motor are used for driving the vehicle; and

the at least one controller being programmed to control the first clutch and the engine as follows;

when a mode switch is carried out from the electrically driven running mode to the hybrid running mode, as the engine is started with progressive engagement of the first clutch, the torque capacity of the first clutch is increased so that an engine rotational speed is increased within a prescribed time to a high-speed region wherein the increase in the engine rotational speed increasing torque caused by the compressive reactive force of the engine can be ignored, and, at the time when the engine rotational speed reaches high-speed region, the torque capacity of the first clutch is decreased.

3. The engine start control system of the according to claim 1, wherein

the at least one controller is further programmed to issue a first clutch torque capacity command for increasing the torque capacity of the first clutch, which decreasing the compressive reactive force is reflected in the target transmission torque of the first clutch adopted in calculating an engagement hydraulic pressure command;

however, the first clutch torque capacity command is not reflected in the torque for increasing the engine rotational speed or the target transmission torque determining a rotational speed profile of the first clutch that determines the time sequence variation in the rotational speed.

4. The engine start control system according to claim 1, wherein

the at least one controller is further programmed to control an increase in the torque capacity of the first clutch starts corresponding to the state of the hydraulic pressure or the stroke of the first clutch.

5. The engine start control system according to claim 4, wherein

in addition to the increase in the engine rotational speed, the at least one controller is further programmed to taken as a condition for not increasing torque capacity of the first clutch whether a slip rotational speed of the second clutch is lower than a prescribed level increase in the first clutch torque capacity.

6. The engine start control system according to claim 4, wherein

in addition to the increase in the engine rotational speed, the at least one controller is further programmed to taken as a condition for not increasing torque capacity of the first clutch whether a difference obtained by subtracting an electrically driven motor torque from the upper limit to the electrically driven motor torque during the slipping of the second clutch is lower than a prescribed level.

7. The engine start control system according to claim 4, wherein

in addition to the increase in the engine rotational speed, the at least one controller is further programmed to taken as a condition for not increasing torque capacity of the first clutch whether a prescribed time has lapsed the fact that the time from the start of the engagement of the first clutch.

8. The engine start control system according to claim 4, wherein

the at least one controller is further programmed such that when the torque capacity of the first clutch cannot be increased so that the prescribed increase in the engine rotational speed can be realized, the torque for increasing the engine rotational speed or the time sequence variation rotational speed is switched.

9. The engine start control system according to claim 1, wherein

the at least one controller is further programmed such that when the torque capacity of the first clutch is increased so that the engine rotational speed is increased within a prescribed time to the high-speed region where the influence of the compressive reactive force of the engine can be ignored, if the influence of the compressive reactive force is significant and the electrically driven motor torque is insufficient due to an unstable engine shutdown position or a short time from the engine shutdown, the torque for increasing the engine rotational speed or the time sequence variation rotational speed profile is switched.

10. The engine start control system according to claim 1, wherein

in the high engine rotational speed region where the increase in the engine rotational speed increasing torque caused by the compressive reactive force of the engine can be ignored, the at least one controller is further programmed such that the torque capacity of the first clutch is determined corresponding to the required load and the vehicle speed.

11. The engine start control system according to claim 1, wherein

when the engine is started by progressive engagement of the first clutch, the at least one controller is further programmed such that the rotational speed of the electrically driven motor is determined corresponding to the increase in the torque capacity of the first clutch.

12. The engine start control system according to claim 3, wherein

the at least one controller is further programmed such that when the torque capacity of the first clutch is increased so that the engine rotational speed is increased within a prescribed time to the high-speed region where the influence of the compressive reactive force of the engine can be ignored, if the influence of the compressive reactive force is significant and the electrically driven motor torque is insufficient due to an unstable engine shutdown position or a short time from the engine shutdown, the torque for increasing the engine rotational speed or the time sequence variation rotational speed is switched.

13. The engine start control system according to claim 3, wherein

in the high engine rotational speed region where the increase in the engine rotational speed increasing torque caused by the compressive reactive force of the engine can be ignored, the at least one controller is further programmed such that the torque capacity of the first clutch is determined corresponding to the required load and the vehicle speed.

14. The engine start control system according to claim 3, wherein

when the engine is started by progressive engagement of the first clutch, the at least one controller is further programmed such that the rotational speed of the electrically driven motor is determined corresponding to the increase in the torque capacity of the first clutch.

15. The engine start control system according to claim 4, wherein

the at least one controller is further programmed such that when the torque capacity of the first clutch is increased so that the engine rotational speed is increased within a prescribed time to the high-speed region where the influence of the compressive reactive force of the engine can be ignored, if the influence of the compressive reactive force is significant and the electrically driven motor torque is insufficient due to an unstable engine shutdown position or a short time from the engine shutdown, the torque for increasing the engine rotational speed or the time sequence variation rotational speed pre-file is switched.

16. The engine start control system according to claim 4, wherein

in the high engine rotational speed region where the increase in the engine rotational speed increasing torque caused by the compressive reactive force of the engine can be ignored, the at least one controller is further programmed such that the torque capacity of the first clutch is determined corresponding to the required load and the vehicle speed.

17. The engine start control system according to claim 4, wherein

when the engine is started by progressive engagement of the first clutch, the at least one controller is further programmed such that the rotational speed of the electrically driven motor is determined corresponding to the increase in the torque capacity of the first clutch.

18. The engine start control system according to claim 5, wherein

the at least one controller is further programmed such that when the torque capacity of the first clutch is increased so that the engine rotational speed is increased within a prescribed time to the high-speed region where the influence of the compressive reactive force of the engine can be ignored, if the influence of the compressive reactive force is significant and the electrically driven motor torque is insufficient due to an unstable engine shutdown position or a short time from the engine shutdown, the torque for increasing the engine rotational speed or the time sequence variation rotational speed profile is switched.

19. The engine start control system according to claim 5, wherein

in the high engine rotational speed region where the increase in the engine rotational speed increasing torque caused by the compressive reactive force of the engine can be ignored, the at least one controller is further programmed such that the torque capacity of the first clutch is determined corresponding to the required load and the vehicle speed.

20. The engine start control system according to claim 5, wherein

when the engine is started by progressive engagement of the first clutch, the at least one controller is further programmed such that the rotational speed of the electrically driven motor is determined corresponding to the increase in the torque capacity of the first clutch.

2. (canceled)