Hybrid drive system wherein clutch in engaged when engine speed has exceeded motor speed upon switching from motor drive mode to engine drive mode

• US 6,655,485 B1
• Filed: 10/06/2000
• Issued: 12/02/2003
• Est. Priority Date: 10/08/1999
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Endo, Hiroatsu, Oba, Hidehiro, Ito, Masatoshi, Hoshiya, Kazumi
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): Bottorff, Christopher
• Application Number:
  US09/684,422
• Time in Patent Office: 1,152 Days
• Field of Search: 180/65.2, 180/65.4, 180/65.6, 180/65.8, 701/22
• US Class Current: 180/65.6
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• 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 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 2260/26 Transition between different drive modes
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• 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 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/107 with endless flexible members
• 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 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: F16D 2500/1066 Hybrid
• CPC Class Codes: F16H 3/725 with means to change ratio in the mechanical gearing
• CPC Class Codes: F16H 61/66 specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38
• CPC Class Codes: F16H 9/18 : only one flange of each pulley being adjustable
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/905 : Combustion engine
• CPC Class Codes: Y10S 903/91 : Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/918 : Continuously variable
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A hybrid vehicle drive system including (a) an engine, (b) an electric motor, (c) a planetary gear device having a first rotary element connected to the engine, a second rotary element connected to the electric motor and connected through a first clutch to an output member connected to vehicle drive wheel, and a third rotary element connected through a second clutch to the output member, (d) a forward-motor-drive control device for engaging the first clutch and releasing the second clutch to thereby establish a forward motor drive mode in which the vehicle is driven in a forward direction by the electric motor, (e) a forward-engine-drive control device for engaging at least the second clutch to establish an engine-drive mode in which the vehicle is driven in the forward direction by the engine, and (f) a second-clutch control device operable upon switching of a vehicle drive mode from the forward motor drive mode to the forward engine drive mode, for engaging the second clutch only after the engine speed has exceeded the motor speed.

Claims

1. A hybrid drive system for an automotive vehicle, comprising:

(a) an engine operable by combustion of a fuel to generate a drive force;

(b) an electric motor;

(c) an output member operatively connected to a drive wheel of the vehicle for driving the vehicle;

(d) a planetary gear device having a first rotary element connected to said engine, a second rotary element connected to said electric motor, and a third rotary element;

(e) a first clutch through which said second rotary element is connected to said output member;

(f) a second clutch through which said third rotary element is connected to said output member;

(g) forward-motor-drive control means for engaging said first clutch and releasing said second clutch to thereby establish a forward motor drive mode in which the automotive vehicle is driven in a forward direction by operation of said electric motor while said engine is at rest;

(h) forward-engine-drive control means for engaging at least said second clutch to establish a forward engine drive mode in which the automotive vehicle is driven in the forward direction by operation of said engine; and

(i) second-clutch control means operable upon switching of a vehicle drive mode from said forward motor drive mode to said forward engine drive mode, for initiating an engagement of said second clutch only after an operating speed of said engine has exceeded an operating speed of said electric motor.

2. A hybrid drive system according to claim 1, wherein said second clutch is a hydraulically operated frictional coupling device capable of effecting a slipping engagement, and said second-clutch control means initiates a gradual increase of a hydraulic pressure to be applied to said second clutch for engaging said second clutch, when the operating speed of said engine has exceeded the operating speed of said electric motor.

3. A hybrid drive system according to claim 1, wherein said second clutch is a hydraulically operated frictional coupling device capable of effecting a slipping engagement, said hybrid drive system further comprising;

first engine-starting means for cranking said engine with a starter, and thereby starting said engine;

second engine-starting means for cranking said engine by slipping engagement of said second clutch, and thereby starting said engine; and

engine-starting means changing means for starting said engine by the control of said engine-starting means when said engine cannot be started by the control of said first engine-starting means.

4. A hybrid drive system according to claim 1, wherein said second-clutch control means is operable to initiate the engagement of said second clutch only after said engine has been completely started and after the operating speed of said engine has exceeded the operating speed of said electric motor.

5. A hybrid drive system according to claim 4, further comprising a starter motor operable to start said engine, and wherein said second-clutch control means is operable to initiate the engagement of said second clutch only after said engine has been completely started by cranking the said starter motor and after the operating speed of said engine has exceeded the operating speed of said electric motor.

6. A hybrid drive system according to claim 2, further comprising motor-torque reducing means operable when said second-clutch control means has initiated said gradual increase of the hydraulic pressure to be applied to said second clutch for engaging said second clutch, said motor-torque reducing means reducing a torque of said electric motor in response to an increase in an engaging torque of said second clutch, so that a sum of said engaging torque of said second clutch and said torque of said electric motor is equal to a drive force of the automotive vehicle desired by an operator of the automotive vehicle.

7. A hybrid drive system according to claim 2, further comprising engine-speed controlling means operable when said second-clutch control means has initiated said gradual increase of the hydraulic pressure to be applied to said second clutch for engaging said second clutch, said engine-speed controlling means controlling the operating speed of said engine according to a rate of increase of the hydraulic pressure to be applied to said second clutch, until the operating speed of said engine has become equal to the operating speed of said electric motor, with full engagement of said clutch.

8. A method for controlling a hybrid drive system for an automotive vehicle, said hybrid drive system comprising:

(a) an engine operable by combustion of a fuel to generate a drive force;

(b) an electric motor;

(c) an output member operatively connected to a drive wheel of the vehicle for driving the vehicle;

(d) a planetary gear device having a first rotary element connected to said engine, a second rotary element connected to said electric motor, and a third rotary element;

(e) a first clutch through which said second rotary element is connected to said output member; and

(f) a second clutch through which said third rotary element is connected to said output member, said method comprising the steps of;

engaging said first clutch and releasing said second clutch to thereby establish a forward motor drive mode in which the automotive vehicle is driven in a forward direction by operation of said electric motor while said engine is at rest;

engaging at least said second clutch to establish a forward engine drive mode in which the automotive vehicle is driven in the forward direction by operation of said engine; and

switching a vehicle drive mode from said forward motor drive mode to said forward engine drive mode, by initiating an engagement of said second clutch only after an operating speed of said engine has exceeded an operating speed of said electric motor.

9. A hybrid drive system for an automotive vehicle, comprising:

(a) an engine operable by combustion of a fuel to generate a drive force;

(b) an electric motor;

(c) an output member operatively connected to a drive wheel of the vehicle for driving the vehicle;

(d) a planetary gear device having a first rotary element connected to said engine, a second rotary element connected to said electric motor, and a third rotary element;

(e) a first clutch through which said second rotary element is connected to said output member;

(f) a second clutch through which said third rotary element is connected to said output member;

(g) forward-motor-drive control means for engaging said first clutch and releasing said second clutch to thereby establish a forward motor drive mode in which the automotive vehicle is driven in a forward direction by operation of said electric motor while said engine is at rest;

(h) forward-engine-drive control means for engaging at least said second clutch to establish a forward engine drive mode in which the automotive vehicle is driven in the forward direction by operation of said engine; and

(i) means operable upon switching of a vehicle drive mode from said forward motor drive mode to said forward engine drive mode,(for initiating an engagement of said second clutch only after an operating speed of said engine has exceeded an operating speed of said electric motor.