Hybrid electric powertrain including a two-mode electrically variable transmission

• US 6,478,705 B1
• Filed: 07/19/2001
• Issued: 11/12/2002
• Est. Priority Date: 07/19/2001
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Holmes, Alan G., Schmidt, Michael Roland
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US09/907,827
• Time in Patent Office: 481 Days
• Field of Search: 475/2, 475/5
• US Class Current: 475/5
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• 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 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• 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 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 2520/10 Longitudinal speed
• CPC Class Codes: B60W 30/18036 : Reversing
• CPC Class Codes: F16H 2037/0866 : Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: F16H 2037/102 : the input or output shaft of the transmission is connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/104 : Power split variators with one end of the CVT connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• 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 903/91 : Orbital, e.g. planetary gears
• 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
• CPC Class Codes: Y10S 903/951 : Assembly or relative location of components

Abstract

A hybrid electric powertrain includes an electrically variable transmission having two differential gearsets coupled to an engine and first and second electrical machines, wherein the gearsets are configurable in input-split and compound-split modes, and wherein shifting between the input-split and compound-split modes occurs at a zero speed point of one of the electric machines for synchronous clutch engagement. The input-split mode provides reverse and low forward ranges, with the first machine operated as a motor and the second as a generator. The compound-split mode provides a high forward range, with the machines selectively operated in motoring or generating modes depending on the speed of the vehicle. Shifting between the input-split and compound-split modes occurs synchronously, and at a zero speed of the first machine, contributing to an exceptionally smooth shift.

Claims

1. A hybrid electric powertrain for driving an output member, the powertrain including an engine, first and second coupled and coaxially aligned gearsets, and first and second electric machines co-axially aligned with the gearsets, the improvement wherein:

the output member is coupled to a gear element of each of the first and second gearsets;

the engine and first electric machine are differentially coupled to the first gearset;

the second electric machine is coupled to a gear element of the second gearset; and

a clutching mechanism selectively couples a gear element of the second gearset (1) to ground to define an input-split mode of operation, and (2) to the first electric machine to define a compound-split mode of operation.

2. The powertrain of claim 1, wherein shifting between the first and second modes of operation occurs when a speed of the first electric machine is substantially zero.

3. The powertrain of claim 2, wherein:

the input-split mode of operation provides reverse and lower forward speed ranges; and

the compound-split mode of operation provides an upper forward speed range.

4. The powertrain of claim 1, wherein:

the clutching mechanism selectively couples the gear element of the second gearset and the first electric machine to ground to define a third mode of operation.

5. An electrically variable transmission having an input and an output, comprising:

first and second co-axially aligned gearsets;

the first gearset having gear elements coupled to the input, the output, and a first electric machine;

the second gearset having gear elements coupled to the output and a second electric machine;

a first clutch mechanism for selectively grounding a mode-changing gear element of the second gearset to define a first mode of operation; and

a second clutch mechanism for selectively coupling the mode-changing gear element of the second gearset to the first electric machine to define a second mode of operation.

6. The transmission of claim 5, wherein the first clutch mechanism is disengaged and the second clutch mechanism engaged to effect a shift from the first mode of operation to the second mode of operation when a speed of the first electric machine is substantially zero.

7. The transmission of claim 5, wherein the first and second gearsets are planetary gearsets, and the output is coupled to a planet carrier of the first gearset and a planet carrier of the second gearset.

8. The transmission of claim 5, wherein the first and second gearsets each have a sun gear, a ring gear and a planet carrier, wherein:

the first machine is coupled to the sun gear of the first gearset;

the second machine is coupled to the sun gear of the second gearset;

the input is coupled to the ring gear of the first gearset; and

the output is coupled to the planet carriers of the first and second gearsets.

9. The transmission of claim 8, wherein the mode-changing gear element is the ring gear of the second gearset.