Vehicle control method and vehicle control device

• US 10,099,677 B2
• Filed: 06/15/2015
• Issued: 10/16/2018
• Est. Priority Date: 06/15/2015
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yoshioka, Youko, Ozawa, Yuuki, Andou, Takao
• Primary Examiner(s): Mawari, Redhwan K
• Application Number:
  US15/572,598
• Publication Number:
  US 20180141535A1
• Time in Patent Office: 1,219 Days
• 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 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 9/18 fed from dc supply lines
• 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 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 2520/04 Vehicle stop
• CPC Class Codes: B60W 2540/103 Accelerator thresholds, e.g. kickdown
• CPC Class Codes: B60W 2710/021 Clutch engagement state
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/085 Torque change rate
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: F16D 2500/1024 : combined with hydraulic actuation
• CPC Class Codes: F16D 2500/10412 : Transmission line of a vehicle
• CPC Class Codes: F16D 2500/1045 : Friction clutch
• CPC Class Codes: F16D 2500/3108 : Vehicle speed
• CPC Class Codes: F16D 2500/3111 : Standing still, i.e. signal detecting when the vehicle is standing still or bellow a certain limit speed
• CPC Class Codes: F16D 2500/31493 : Switches on the dashboard
• CPC Class Codes: F16D 2500/70406 : Pressure
• CPC Class Codes: F16D 2500/7041 : Position
• CPC Class Codes: F16D 2500/70454 : Engine speed
• CPC Class Codes: F16D 48/06 : Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A vehicle control device is provided with a friction clutch for engaging and disengaging a motor/generator and a drive wheel, a mechanical oil pump driven by the motor/generator to supply hydraulic oil pressure to the friction clutch, an electric oil pump driven by an electric motor to supply hydraulic oil pressure to the friction clutch, and a control unit. The control unit stops a motor/generator when a vehicle stops; maintains a release of a friction clutch when slack in the stroke is eliminated by the hydraulic oil pressure from the electric oil pump; raises a rotational speed of the motor/generator toward a target rotational speed upon a request to cancel stoppage of the motor/generator; and restricts the torque to be less than the motor generator torque at which the target rotational rate can be maintained when the rotational rate of the motor/generator is raised toward the target rotational rate.

Claims

1. A vehicle control method of controlling a vehicle, the vehicle control method comprising:

a friction clutch that is configured to switch between engagement and disengagement between a motor/generator and a drive wheel;

a mechanical oil pump that is driven by the motor/generator and supplies hydraulic oil pressure to the friction clutch; and

an electric oil pump that is driven by an electric motor and supplies hydraulic oil pressure to the friction clutch,

the motor/generator being stopped when the vehicle is stopped,

the friction clutch being kept released by the hydraulic pressure from the electric oil pump in a state in which slack in a stroke is eliminated,

a rotational speed of the motor/generator being increased toward a target rotational speed upon receiving a motor stoppage cancellation request of the motor/generator, and

when increasing the rotational speed of the motor/generator toward the target rotational speed, a torque of the motor/generator is limited to less than the torque of the motor/generator at which it is possible to maintain the target rotational speed, and if a slip of the friction clutch is detected, then limitation of the torque is canceled.

2. The vehicle control method as recited in claim 1, wherein

the limitation of the torque is for limiting a change rate of the torque such that a slip occurs in the friction clutch within a predetermined time after the motor stoppage cancellation request is made.

3. The vehicle control method as recited in claim 1, wherein

if a value indicating an acceleration request of a driver exceeds a threshold value, then the limitation of the torque is canceled.

5. The vehicle control method as recited in claim 2, wherein

if a value indicating an acceleration request of a driver exceeds a threshold value, then the limitation of the torque is canceled.

4. A vehicle control device comprising:

a friction clutch that is configured to switch between engagement and disengagement between a motor/generator and a drive wheel,

a mechanical oil pump that is driven by the motor/generator and supplies hydraulic oil pressure to the friction clutch;

an electric oil pump that is driven by an electric motor and supplies hydraulic oil pressure to the friction clutch; and

a control unit that stops the motor/generator when the vehicle is stopped, keeps the friction clutch released by the hydraulic pressure from the electric oil pump in a state in which slack in a stroke is eliminated, increases a rotational speed of the motor/generator toward a target rotational speed upon receiving a stoppage cancellation request of the motor/generator, and limits a torque of the motor/generator to less than the torque of the motor/generator at which it is possible to maintain the target rotational speed when increasing the rotational speed of the motor/generator toward the target rotational speed, and if a slip of the friction clutch is detected, then cancels limitation of the torque.