Hybrid vehicle drive control system

• US 9,580,068 B2
• Filed: 10/31/2012
• Issued: 02/28/2017
• Est. Priority Date: 11/25/2011
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Mohri, Takanobu
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): PECHE, JORGE O
• Application Number:
  US14/356,736
• Publication Number:
  US 20150051767A1
• Time in Patent Office: 1,581 Days
• Field of Search: 701/22, 701/54, 701/67, 701/68, 701/69, 701/84, 701/101, 477/5, 477/8, 477/13, 477/39, 477/57, 477/77, 180/65.21, 180/65.245, 180/65.28, 180/278, 180/293
• US Class Current: 1/1
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• 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 2240/485 Temperature
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• 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 10/107 with endless flexible members
• 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 2710/081 Speed
• CPC Class Codes: F02N 11/0851 : characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• 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 903/93 : Conjoint control of different elements

Abstract

A hybrid vehicle drive control system is configured to start an engine irrespective of a motor rotational speed or a driving scene. In the hybrid vehicle drive control system, upon receiving an engine startup request, the engine is started by engaging a first clutch provided between the engine and a motor using the torque of the motor. A second clutch is provided between the motor and the drive wheel. The second clutch is disengaged by a second clutch control operation to reduce the motor rotation speed as a result of the motor rotational speed control by a motor rotation speed-controlling operation. The control system may thus increase the maximum motor output enable torque to ensure the start of the engine by the surplus torque irrespective of a motor rotational speed or driving scene.

Claims

1. A hybrid vehicle drive control system for a hybrid vehicle which comprises a drive system including an engine, a motor, a first clutch disposed between the engine and the motor, a second clutch disposed between the engine and a drive wheel, and operative, upon receipt of an engine start request, to engage the first clutch to thereby start the engine using a torque of the motor, the hybrid vehicle drive control system comprising:

a first controller programmed to conduct a second clutch control of the second clutch to disconnect a torque transmission path between the motor and the drive wheel upon the engine start request;

a second controller programmed to reduce a motor rotational speed through a motor rotational speed reduction control of the motor while the torque transmission path between the motor and the drive wheel is disconnected;

a third controller programmed to engage the first clutch to start the engine using the torque of the motor while the motor rotational speed is reduced, and to fully engage the second clutch after complete combustion of the engine; and

a fourth controller programmed to conclude a downshift of a transmission, during a time from starting the engine to a time of full engagement of the second clutch in the torque transmission path between the motor and the drive wheel being disconnected,

the second controller being further programmed to set a target motor rotational speed for the motor rotational speed reduction control to be equal to or greater than a lower limit amount, the lower limit amount being a value at which a discharge amount of a mechanical oil pump is at a minimum discharge amount necessary to operate the first clutch, the mechanical oil pump being operable by a rotational drive power of a motor shaft of the motor, and

the second controller being further programmed to set the target motor rotational speed for reduction to be less than or equal to an upper limit amount, the upper limit amount being a value that secures a minimum lifetime of the first clutch.

2. The hybrid vehicle drive control system as claimed in claim 1, wherein

the second controller is further programmed to conduct the motor rotational speed reduction control of the motor when a surplus torque obtained by subtracting a motor drive torque for vehicle propulsion from a maximum output enable torque of the motor is determined to be less than an engine start torque necessary for startup of the engine.