Control apparatus for hybrid vehicle

• US 8,452,469 B2
• Filed: 02/23/2009
• Issued: 05/28/2013
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Otokawa, Kayo
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Hilgendorf, Dale W
• Application Number:
  US12/811,490
• Publication Number:
  US 20100286858A1
• Time in Patent Office: 1,555 Days
• Field of Search: 701/22, 701/36, 701/51, 701/52, 701/53, 701/54, 701/58, 701/60, 701/61, 701/62, 701/64, 701/67, 701/68, 701/69, 701/99, 701/111, 180/65.2, 180/65.25, 180/65.26, 180/65.265, 180/65.27, 180/65.275, 180/65.28, 180/305, 477/3, 477/4, 477/5, 903/902, 903/903, 903/914
• US Class Current: 701/22
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• 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 2240/445 Temperature
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/525 Temperature of converter or components thereof
• CPC Class Codes: B60L 2240/80 Time limits
• 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 10/115 with planetary gears
• CPC Class Codes: B60W 2510/0275 Clutch torque
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/1005 : Transmission ratio engaged
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2520/28 : Wheel speed
• CPC Class Codes: B60W 2540/06 : Ignition switch
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2710/027 : Clutch torque
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/1061 : Output power
• 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: F02D 29/02 : peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/042 : for stopping the engine
• CPC Class Codes: G06G 7/70 : for vehicles, e.g. to determine permissible loading of ships , centre of gravity, necessary fuel
• 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

Abstract

A hybrid vehicle control apparatus is provided with an engine, an electric motor, a holding element, an automatic transmission, a range position detecting device and a controller. The holding element is arranged between the engine and the electric motor to selectively connect and disconnect the engine and the electric motor to and from each other. The automatic transmission is arranged between the electric motor and a drive wheel. The range position detecting device detects a range position of the automatic transmission selected by a driver. The controller executes a control operation serving to stop the engine while also executing a slip control serving to lower a torque transfer capacity of the holding element upon a determination that a request to stop the engine has occurred while the engine is operating, the holding element is engaged, and the automatic transmission is detected in a non-driving range.

Claims

1. A hybrid vehicle control apparatus comprising:

an engine;

an electric motor;

a holding element arranged between the engine and the electric motor to selectively connect and disconnect the engine and the electric motor to and from each other;

an automatic transmission arranged between the electric motor and a drive wheel;

a range position detecting device arranged to detect a range position of the automatic transmission selected by a driver;

an engine rotational speed detecting device arranged to detect a rotational speed of the engine;

an electric motor rotational speed control detecting device arranged to detect a rotational speed of the electric motor; and

a controller configured to execute a control operation serving to stop the engine while also executing a slip control serving to lower a torque transfer capacity of the holding element upon a determination that a request to stop the engine has occurred while the engine is operating, the holding element is engaged, and the range position detecting device detects the automatic transmission in a non-driving range, the controller being further configured to control the electric motor such that the rotational speed of the electric motor remains below the rotational speed of the engine until the rotational speed of the engine decreases to a rotational speed that is lower than a prescribed resonance band rotational speed region, and the controller being further configured to control the electric motor such that the rotational speed of the electric motor is higher than the rotational speed of the engine after the rotational speed of the engine has decreased to the rotational speed that is lower than the prescribed resonance band rotational speed region and while the engine is still rotating.

2. The hybrid vehicle control apparatus of claim 1, wherein

the controller is further configured to execute the slip control of the holding element after a fuel supply to the engine has been stopped upon establishing that the determination that the request to stop the engine has occurred.

3. The hybrid vehicle control apparatus of claim 1, wherein

the controller is further configured to control the electric motor such that the rotational speed of the electric motor is substantially equal to a rotational speed target value of the electric motor;

and

the controller is further configured to lower a torque transfer capacity of the holding element, then rapidly lower the rotational speed target value of the electric motor at a first rate, and then gradually lower the rotational speed target value of the electric motor at a second rate that is smaller than the first rate.

4. The hybrid vehicle control apparatus of claim 1, wherein

the controller is further configured to engage the holding element completely when a difference between the rotational speed of the electric motor and the rotational speed of the engine becomes equal to or smaller than a prescribed rotational speed after the rotational speed of the engine has decreased to a rotational speed below the prescribed resonance band rotational speed region.

5. The hybrid vehicle control apparatus of claim 1, wherein

the holding element is a normally-closed clutch arranged to be closed by an engagement force exerted by a force producing mechanism when at least one of a control oil flow rate and a control oil pressure is zero.

6. The hybrid vehicle control apparatus of claim 1, wherein

the controller is further configured to maintain the torque transfer capacity of the holding element to a prescribed value during the slip control.

8. The hybrid vehicle control apparatus of claim 6, wherein

the controller is further configured to temporarily lower the torque transfer capacity of the holding element, and subsequently raise the torque transfer capacity of the holding element to the prescribed value prior to maintaining the torque transfer capacity of the holding element to the prescribed value during the slip control.

7. A hybrid vehicle control method comprising:

detecting a range position of an automatic transmission selected by a driver in which the automatic transmission is coupled between an electric motor and a drive wheel;

detecting a rotational speed of the engine;

detect a rotational speed of the electric motor; and

executing a control operation serving to stop an engine that is selectively coupled to the electric motor by a holding element that selectively connects and disconnects the engine to and from the electric motor while also executing a slip control serving to lower a torque transfer capacity of the holding element upon a determination that a request to stop the engine has occurred while the engine is operating, the holding element is engaged, and the automatic transmission is detected in a non-driving range, to control the electric motor such that the rotational speed of the electric motor remains below the rotational speed of the engine until the rotational speed of the engine decreases to a rotational speed that is lower than a prescribed resonance band rotational speed region, and to control the electric motor such that the rotational seed of the electric motor is higher than the rotational seed of the engine after the rotational speed of the engine has decreased to the rotational speed that is lower than the prescribed resonance band rotational speed region and while the engine is still rotating.