HYBRID VEHICLE AND CONTROL FOR A CLUTCH ENGAGING EVENT

• US 20130178330A1
• Filed: 01/11/2012
• Published: 07/11/2013
• Est. Priority Date: 01/11/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Nefcy, Bernard D., Colvin, Daniel Scott, Kraska, Marvin Paul, Ortmann, Walter Joseph, Soo, Brian Thomas
• Granted Patent: US 8,834,320 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: F16D 2500/1066 Hybrid
• CPC Class Codes: F16D 2500/30406 Clutch slip
• CPC Class Codes: F16D 2500/3108 Vehicle speed
• CPC Class Codes: F16D 2500/50287 Torque control
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure

Abstract

A method for controlling a downstream clutch in a vehicle during an upstream torque disturbance includes slipping a downstream clutch by reducing the downstream clutch pressure, varying the downstream clutch pressure to a target threshold to control the slip of the downstream clutch, increasing the downstream clutch pressure to engage the downstream clutch. A vehicle includes a first prime mover, a second prime mover connected to the first prime mover using an upstream clutch, a transmission connected to the second prime mover using a downstream clutch, and a controller connected to the first and second prime movers and the upstream and downstream clutches. The controller is configured to (i) slip the downstream clutch by reducing the pressure, (ii) vary the downstream clutch pressure to a target threshold to control the slip, and (iii) increase the downstream clutch pressure to engage the clutch.

Claims

1. A method for controlling a downstream clutch in a hybrid vehicle, comprising:

slipping the downstream clutch by reducing downstream clutch pressure;

varying the downstream clutch pressure in response to a target threshold to control the slip of the downstream clutch; and

increasing the downstream clutch pressure to engage the downstream clutch.

2. The method of claim 1 wherein the upstream torque disturbance is an upstream clutch engaging event.

3. The method of claim 1 wherein the target threshold is determined from a model of torque for incipient slip.

4. The method of claim 1 wherein the target threshold varies with driver demanded and produced torque for the vehicle.

5. The method of claim 4 wherein the target threshold varies with slip speed.

6. The method of claim 1 wherein varying the downstream clutch pressure includes increasing the downstream clutch pressure to control the slip by offsetting the downstream clutch pressure above the target threshold.

7. The method of claim 1 further comprising engaging an upstream clutch while slipping the downstream clutch.

8. The method of claim 1 wherein varying the downstream clutch pressure includes maintaining the increased torque pressure at an offset above the target threshold until the slip falls below a calibrated value.

9. The method of claim 8 wherein varying the downstream clutch pressure includes reducing the downstream clutch pressure by removing the offset such that the downstream clutch pressure is approximately equal to the target threshold to decrease a rate of change of slip to land the downstream clutch.

10. The method of claim 1 wherein varying the downstream clutch pressure includes reducing the downstream clutch pressure as the slip approaches zero to land the clutch.

11. The method of claim 1 wherein slipping the downstream clutch isolates a driveline of the vehicle from disturbances.

12. The method of claim 1 wherein all of an input torque to a transmission flows through the downstream clutch.

13. A method for controlling a downstream clutch in a hybrid vehicle, the downstream clutch connecting an electric machine to a transmission, the method comprising:

decreasing downstream clutch pressure at a first rate;

decreasing the downstream clutch pressure at a second rate to initiate slip of the downstream clutch, the second rate lower than the first rate;

increasing the downstream clutch pressure to reduce the slip of the downstream clutch at a first slip rate;

decreasing the downstream clutch pressure to reduce the first slip rate to land the clutch;

increasing the downstream clutch pressure at a third rate to reduce the slip to zero; and

increasing the downstream clutch pressure at a fourth rate to a locked clutch pressure, the fourth rate higher than the third rate.

14. The method of claim 13 wherein increasing the downstream clutch pressure to reduce the slip comprises:

increasing the downstream clutch pressure to an offset above a target threshold to control the slip of the downstream clutch, the target threshold including a driver demanded and supplied torque component, and a rotational inertia component associated with upstream components rotating while the downstream clutch is slipping.

15. The method of claim 13 wherein input torque to the transmission flows through the downstream clutch.

16. A vehicle comprising:

a first prime mover;

a second prime mover connected to the first prime mover using an upstream clutch;

a transmission connected to the second prime mover using a downstream clutch; and

a controller connected to the first and second prime movers and the upstream and downstream clutches, the controller configured to (i) slip the downstream clutch by reducing the downstream clutch pressure, (ii) vary the downstream clutch pressure in response to a target threshold to control the slip of the downstream clutch, and (iii) increase the downstream clutch pressure to engage the downstream clutch.

17. The vehicle of claim 16 wherein the controller is configured to increase the downstream clutch pressure to control the slip by offsetting the downstream clutch pressure above the target threshold.

18. The vehicle of claim 17 wherein the controller is configured to reduce the downstream clutch pressure by removing the offset such that the downstream clutch pressure is approximately equal to the target threshold to decrease a rate of change of slip to land the downstream clutch.

19. The vehicle of claim 16 wherein the downstream clutch is a torque converter.

20. The vehicle of claim 16 wherein the first prime mover, the upstream clutch, the second prime mover, the downstream clutch, and the transmission are in line with one another.