Synchronized coast downshift control for hybrid vehicles

• US 6,019,699 A
• Filed: 01/21/1999
• Issued: 02/01/2000
• Est. Priority Date: 02/04/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Oba, Hidehiro, Hoshiya, Kazumi
• Primary Examiner(s): Ta, Khoi Q.
• Application Number:
  US09/234,375
• Time in Patent Office: 376 Days
• Field of Search: 477/3, 477/1, 477/15, 477/18, 477/20, 74/336 R
• US Class Current: 477/20
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/383 One-way clutches or freewheel devices
• 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 2240/486 Operating parameters
• 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 10/10 including control of change-speed gearings
• 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 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/1011 Input shaft speed, e.g. turbine speed
• CPC Class Codes: F16H 2059/144 characterised by change between positive and negative drive line torque, e.g. torque changes when switching between coasting and acceleration
• CPC Class Codes: F16H 2059/186 Coasting
• CPC Class Codes: F16H 2061/0422 by an electric machine, e.g. by accelerating or braking the input shaft
• CPC Class Codes: F16H 2061/044 when a freewheel device is disengaged or bridged
• CPC Class Codes: F16H 61/04 Smoothing ratio shift
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/91 : Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/913 : One way
• CPC Class Codes: Y10S 903/917 : with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A drive control system for a hybrid vehicle for preventing a delay in the application of a one-way clutch in a transmission and an application shock. In this drive control system, an electric motor and an internal combustion engine are coupled to the input side of a transmission having at least one gear stage to be set by applying a one-way clutch. The drive control system comprises: a detector for detecting a coasting state in which the one-way clutch is released in a deceleration state set with the gear stage; and an input speed raising device for driving the electric motor when the coasting state is detected, so that the input speed of the transmission may approach the synchronous speed which is the product of the gear ratio of the gear stage to be set by applying the one-way clutch and the output speed of the transmission.

Claims

1. A drive control system for a hybrid vehicle, in which an electric motor and an internal combustion engine are coupled to the input side of a transmission capable of at least one gear stage for applying a one-way clutch, comprising:

coasting state detecting means for detecting a coasting state in which said one-way clutch is released in a deceleration state set with said gear stage; and

input speed raising means for driving said electric motor when said coasting state is detected, so that the input speed of said transmission may approach the synchronous speed which is the product of the gear ratio of the gear stage to be set by applying said one-way dutch and the output speed of said transmission.

2. A hybrid vehicle drive control system according to claim 1,

wherein said input speed raising means includes means for augmenting the input speed of said transmission gradually by augmenting the speed of said electric motor by a predetermined additional speed.

3. A hybrid vehicle drive control system according to claim 1,

wherein said input speed raising means includes means for augmenting the speed of said electric motor till the input speed of said transmission comes into coincidence with said synchronous speed.

4. A hybrid vehicle drive control system according to claim 1,

wherein said input speed raising means includes means for augmenting the speed of said electric motor till the input speed of said transmission reaches an input speed smaller by a predetermined value than said synchronous speed.

5. A hybrid vehicle drive control system according to claim 1,

wherein said electric motor has an electric power generating function.

6. A hybrid vehicle drive control system according to claim 1,

wherein said internal combustion engine includes a torque synthesizing/distributing mechanism for synthesizing the torque outputted by said internal combustion engine and the torque outputted by said electric motor, to input the synthesized torque to said transmission.

7. A hybrid vehicle drive control system according to claim 6,

wherein said torque synthesizing/distributing mechanism includes a differential mechanism.

8. A hybrid vehicle drive control system according to claim 6,

wherein said torque synthesizing/distributing mechanism includes:

a set of planetary gear mechanism having a sun gear, a ring gear arranged concentrically with said sun gear, and a carrier rotatably retaining a pinion gear meshing with said sun gear and said ring gear;

an input clutch for connecting said ring gear selectively to said internal combustion engine; and

an integral clutch for connecting said carrier and said sun gear selectively,

wherein said sun gear is connected to said electric motor, and wherein said carrier is connected to said transmission.