Method and apparatus for controlling the speed of an engine within a hybrid electric vehicle

• US 6,877,575 B2
• Filed: 03/31/2000
• Issued: 04/12/2005
• Est. Priority Date: 03/31/2000
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: McCarthy, James Paul
• Primary Examiner(s): Ellis, Christopher P.
• Assistant Examiner(s): AVERY, BRIDGET D
• Application Number:
  US09/539,394
• Publication Number:
  US 20030047361A1
• Time in Patent Office: 1,838 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.4, 180/65.6
• US Class Current: 180/65.235
• CPC Class Codes: B60K 17/02 characterised by arrangement, location, or kind of clutch
• 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 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/441 Speed
• 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 10/26 for electrical energy, e.g. batteries or capacitors
• 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 2710/0666 Engine torque
• CPC Class Codes: F16H 1/22 with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
• 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 3/72 with a secondary drive, e.g. regulating motor, in order to vary speed continuously
• CPC Class Codes: F16H 3/724 using external powered electric machines
• CPC Class Codes: F16H 3/727 with at least two dynamo electric machines for creating an electric power path inside the gearing, e.g. using generator and motor for a variable power torque path special adapted for a hybrid electric vehicle B60K6/20
• CPC Class Codes: H02K 51/00 Dynamo-electric gears, i.e. dynamo-electric means for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts
• 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: Y10S 903/914 : Actuated, e.g. engaged or disengaged by electrical, hydraulic or mechanical means
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A hybrid electric vehicle drive system or transaxle 10 including an internal combustion engine 12, a generator/motor 14 which is coupled to engine 12 by use of a planetary gear set 20, and an electric motor 16. Drive system 10 includes a brake or clutch assembly 34 which is operatively and selectively coupled to a generator/motor 14 and is effective to supplement the generator-produced reaction torque, thereby cooperating with the generator/motor 14 to control the speed of engine 12.

Claims

1. A vehicle drive system comprising:

an engine having an output shaft which rotates at a first speed;

a generator which is operatively coupled to said engine which selectively produces a reaction torque, effective to control said first speed;

a power transfer unit interconnecting the engine and the generator, the power transfer unit being configured to receive torque from the engine and the generator, and to deliver torque to drive the vehicle; and

a clutch assembly having a first portion coupled to said generator such that the first portion can be rotated by said generator regardless of the direction of rotation of said generator, said clutch assembly having another portion rotationally fixed, wherein said clutch assembly is selectively engageable to provide a braking torque to said generator and which is effective to selectively augment said reaction torque of said generator, thereby selectively increasing said reaction torque applied to said output shaft by said generator to control said first speed, and wherein at least a portion of the clutch assembly is disposed on a hub portion of the generator, located to allow full torque transfer between the engine and the power transfer unit when the clutch assembly is engaged.

2. The drive system of claim 1 further comprising:

a controller which is communicatively coupled to said generator, to said engine, and to said clutch assembly, said controller being effective to determine an amount of reaction torque required to control said first speed, and based upon said amount of reaction torque, to cause said generator and said clutch assembly to cooperatively provide said reaction torque.

3. The drive system of claim 1 wherein said generator is coupled to said engine by use of a planetary gear set.

4. The drive system of claim 2 wherein said clutch assembly is communicatively coupled to a source of pressurized fluid by use of a selectively actuatable valve assembly, and wherein said controller is effective to selectively actuate said valve assembly, thereby controlling said reaction torque.

5. The drive system of claim 4, wherein said valve assembly comprises a variable solenoid valve.

6. The drive system of claim 3, further comprising a motor which cooperates with said generator and said engine to power said drive system.

7. The drive system of claim 6 wherein said motor, said engine, and said generator are arranged in a power-split configuration.

8. An apparatus for use within a vehicle including an engine which operates at a first speed, said apparatus being effective to control said first speed and comprising:

a generator including a stator assembly and a rotor assembly which is operatively coupled to said engine, said generator being effective to selectively provide a first torque through said rotor assembly, said torque being effective to control said first speed;

a power transfer unit interconnecting the engine and the generator, the power transfer unit being configured to receive torque from the engine and the generator, and to deliver torque to drive the vehicle; and

a clutch assembly having at least one friction plate fixedly coupled to said vehicle and rotationally stationary, and at least one divider plate coupled to said rotor assembly such that the at least one divider plate can be rotated by said rotor assembly regardless of the direction of rotation of said rotor assembly, the at least one divider plate being selectively and frictionally engageable with said at least one friction plate effective to provide a second torque through said rotor assembly, said second torque being effective to augment said first torque, thereby further controlling said first speed, and wherein at least a portion of the clutch assembly is disposed on a hub portion of the generator, located to allow full torque transfer between the engine and the power transfer unit when the clutch assembly is engaged.

9. The apparatus of claim 8 wherein said clutch assembly includes a drum portion, a plurality of first plates which are coupled to said drum portion, a plurality of second plates which are coupled to said generator, and a piston which is effective to selectively compress said plurality of first and second plates, thereby providing said second torque.

10. The apparatus of claim 8 wherein said clutch assembly comprises a hydraulic clutch assembly.

11. The apparatus of claim 8 wherein said engine and said generator are operatively coupled by use of a planetary gear set.

12. The apparatus of claim 9 further comprising:

a sensor which measures said first speed and which generates a first signal based upon said measured first speed; and

a controller which is communicatively coupled to said sensor, to said generator and to said clutch assembly, said controller being effective to receive said first signal and, based upon said first signal, to selectively cause said generator to provide said first torque.

13. The apparatus of claim 12 wherein said controller is further effective to compare said first signal to a threshold value and if said first signal exceeds said threshold value to selectively cause said clutch assembly to provide said second torque.

14. A method for controlling the speed of an engine within a vehicle including a generator having a rotor assembly which is operatively coupled to said engine, said method comprising the steps of:

selectively activating said generator effective to produce a negative torque which lowers said speed of said engine;

providing a power transfer unit interconnecting the engine and the generator, the power transfer unit being configured to receive torque from the engine and the generator, and to deliver torque to drive the vehicle;

providing a clutch assembly having non-rotating friction plates and divider plates which are coupled to said rotor assembly, wherein said plates of said clutch assembly may be operatively engaged to create a frictional braking force, and wherein at least a portion of the clutch assembly is disposed on a hub portion of the generator, located to allow full torque transfer between the engine and the power transfer unit when the clutch assembly is engaged; and

selectively and frictionally engaging said clutch member plates to impart said created frictional braking force to said rotor assembly effective to further lower said speed of said engine.

15. The method of claim 14 further comprising the steps of:

monitoring said speed;

comparing said measured speed to a first threshold value; and

selectively activating said generator if said measured speed exceeds said threshold value effective to cause said speed to remain below said threshold value.

16. The method of claim 15 wherein said generator has a capacity, said method further comprising the steps of:

determining whether said capacity has been exceeded; and

selectively and frictionally engaging said rotor assembly if said capacity has been exceeded, thereby causing said speed to remain below said threshold value.

17. The method of claim 16 wherein said rotor assembly is selectively and frictionally engaged by use of a brake assembly.

18. The method of claim 16 wherein said rotor assembly is selectively and frictionally engaged by use of a clutch assembly.

19. The method of claim 16 wherein said engine and said rotor assembly are operatively interconnected by use of a planetary gear set.