Controlling Torque in a Flywheel Powertrain

• US 20110071000A1
• Filed: 09/18/2009
• Published: 03/24/2011
• Est. Priority Date: 09/18/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ortmann, Walter J.
• Granted Patent: US 8,142,329 B2
• Time in Patent Office: Days
• US Class Current: 477/39
• CPC Class Codes: B60K 6/105 the accumulator being a flywheel
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/107 with endless flexible members
• CPC Class Codes: B60W 2050/0012 Feedforward or open loop systems
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method for controlling a powertrain for an automotive vehicle includes determining a desired flywheel torque, determining, with reference to the desired flywheel torque, a desired torque capacity torque of a clutch through which torque is transmitted between the flywheel and wheels of the vehicle, operating the clutch to produce the desired clutch torque capacity, determining a slip error across the clutch, and changing a gear ratio of a continuously variable transmission located in a drive path between the clutch and said wheels to a gear ratio that reduces the slip error.

Claims

1. A method for controlling an automotive vehicle powertrain, comprising the steps of:

(a) producing a desired torque capacity in a clutch through which torque is transmitted between a flywheel and vehicle wheels; and

(b) reducing a slip error across the clutch by adjusting a gear ratio of a continuously variable transmission located in a drive path between the clutch and the wheels.

2. The method of claim 1, wherein step (a) further comprises:

using a driver demanded wheel torque to determine a desired flywheel torque; and

using the desired flywheel torque to determine the desired torque capacity of the clutch.

3. The method of claim 2, wherein step (a) further comprises using displacement of one of an accelerator pedal and an engine throttle to determine the desired flywheel torque.

4. The method of claim 1, wherein step (a) further comprises using a current gear ratio produced by the transmission and a desired flywheel output torque to determine the desired torque capacity of the clutch.

5. The method of claim 1, wherein step (a) further comprises:

changing the clutch torque capacity to the desired clutch torque capacity; and

transmitting torque through the clutch.

6. The method of claim 1, wherein step b) further comprises:

determining a desired clutch slip;

determining a current clutch slip; and

determining the slip error across the clutch as the difference between the desired clutch slip and the current clutch slip.

7. The method of claim 1, wherein step (b) further comprises:

using a controller to determine from the slip error a change in gear ratio produced by the transmission that reduces the slip error.

8. A method for controlling an automotive vehicle powertrain, comprising the steps of:

(a) producing a desired torque capacity in a clutch through which torque is transmitted between the flywheel and wheels of the vehicle at a magnitude corresponding to a desired flywheel torque;

(b) determining a slip error across the clutch; and

(c) using a continuously variable transmission located in a drive path between the clutch and said wheels to reduce the slip error.

9. The method of claim 8, wherein step (a) further comprises using a driver demanded wheel torque to determine the desired flywheel torque.

10. The method of claim 8, wherein step (a) further comprises using a current gear ratio produced by the transmission and a desired flywheel output torque to determine the desired torque capacity of the clutch.

11. The method of claim 8, wherein step (a) further comprises:

changing the clutch torque capacity to the desired clutch torque capacity; and

transmitting torque through the clutch.

12. The method of claim 8, wherein step (b) further comprises:

determining a desired clutch slip;

determining a current clutch slip; and

determining the slip error across the clutch as the difference between the desired clutch slip and the current clutch slip.

13. The method of claim 8, wherein step (c) further comprises:

using a controller to determine from the slip error said change in gear ratio produced by the transmission.

14. A system for transmitting power in a powertrain for an automotive vehicle, comprising:

a flywheel;

vehicle wheels;

a clutch through which torque is transmitted between the flywheel and said wheels;

a continuously variable transmission located in a drive path between the clutch and said wheels;

a final drive mechanism located in series relation with said transmission in a drive path between said transmission and said wheels.

15. The system of claim 14, further comprising:

a first gear driveably connected to the transmission; and

a first pinion meshing with the first gear and driveably connected to the final drive mechanism.

16. The system of claim 14, further comprising:

a planetary gearset including a sun gear secured to the flywheel, a ring gear fixed against rotation, a carrier, and planet pinions supported on the carrier and meshing with the sun gear and ring gear, the carrier being driveably connected to the clutch.

17. The system of claim 16, further comprising:

a second gear driveably connected to the carrier; and

a second pinion meshing with the second gear and driveably connected to the clutch.