Vehicle launch using a transmission input clutch

• US 7,998,026 B2
• Filed: 01/17/2008
• Issued: 08/16/2011
• Est. Priority Date: 01/17/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hrovat, Davor D., Oldknow, Ian, Jiang, Hong, Asgari, Jahan, Fodor, Michael G.
• Primary Examiner(s): ESTREMSKY, SHERRY LYNN
• Application Number:
  US12/015,920
• Publication Number:
  US 20090186743A1
• Time in Patent Office: 1,307 Days
• Field of Search: 477/175, 701/67
• US Class Current: 477/175
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: F16D 2500/30406 Clutch slip
• CPC Class Codes: F16D 2500/30421 Torque of the output shaft
• CPC Class Codes: F16D 2500/3144 Accelerator pedal position
• CPC Class Codes: F16D 2500/50287 Torque control
• CPC Class Codes: F16D 2500/7044 Output shaft torque
• CPC Class Codes: F16D 2500/70605 Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 2500/7082 of the clutch
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure

Abstract

A method for controlling a transmission input clutch during a vehicle launch includes selecting a subject device that transmits torque between an input and an output, a providing a mathematical model of the subject device, such that the model employing only static relationships of engine speed and transmission input speed to a desired magnitude of torque produced by the subject device, using the model, the current engine speed and the current engine speed to determine the desired torque produced by the subject device, and adjusting the torque capacity of the clutch to the desired torque of the subject device determined from the model.

Claims

1. A method for controlling a clutch that transmits torque between an engine and transmission, comprising:

(a) using a model of the clutch that includes static relationships of engine speed and transmission input speed to a desired clutch torque;

(b) determining the desired clutch torque from the model using current engine speed and current transmission input speed;

(c) adjusting the torque capacity of the clutch to said desired clutch torque.

2. The method of claim 1 wherein the method further comprises the step of:

preventing an increase in the torque capacity of the clutch, if an accelerator pedal position is decreasing.

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

including in the model the relation T_desired=k(N_{eng −}

N_trans) wherein T_desired is the desired torque produced by the subject device, N_eng is engine speed, N_trans is transmission input shaft speed, and k is an adjustable proportionality constant.

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

including in the model the relations T_desired=[N_eng/R]² and R=fn[N_eng/N_trans] wherein T_desired is the desired clutch torque, N_eng is engine speed, N_trans is transmission input shaft speed, and R is a capacity factor of a device represented by the model.

5. The method of claim 1 further comprising the steps of:

providing a supervisory controller that includes a second model for producing an ideal engine speed;

determining an engine speed error by comparing the ideal engine speed and the actual engine speed;

using the engine speed error to correct the desired clutch torque produced by the first model toward an ideal clutch torque produced by the supervisory controller.

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

providing the model such that the model produces a desired clutch torque and is unresponsive to an engine speed error with respect to an engine speed target.

7. A method for controlling a clutch that transmits torque between an engine and transmission during a vehicle launch, comprising:

(a) using a model of the clutch that includes static relationships of engine speed and transmission input speed to determine a desired clutch torque;

(b) using an ideal clutch torque for said launch produced by a second model to correct the desired clutch torque;

(c) adjusting the torque capacity of the clutch to the corrected desired clutch torque.

8. The method of claim 7 wherein the method further comprises the step of:

preventing an increase in the torque capacity of the clutch, if an accelerator pedal position is decreasing.

9. The method of claim 7 wherein step (a)) further comprises:

including in the model the relation T_desired=k(N_{eng −}

N_trans) wherein T_desired is the desired torque produced by the subject device, N_eng is engine speed, N_trans is transmission input shaft speed, and k is an adjustable proportionality constant.

10. The method of claim 7 wherein step (a) further comprises:

including in the model the relations T_desired=[N_eng/R]² and R=fn[N_eng/N_trans] wherein T_desired is the desired torque produced by the subject device, N_eng is engine speed, N_trans is transmission input shaft speed, and R is a capacity factor of the selected device.

11. The method of claim 7 wherein step (b) further comprises the steps of:

providing a supervisory controller that includes the second model and produces an ideal engine speed for said launch,

determining an engine speed error by comparing the ideal engine speed and the actual engine speed; and

using said controller and the engine speed error to determine the ideal clutch torque for said launch.

12. The method of claim 7 wherein step (a) further comprises:

providing the model such that the model produces a desired clutch torque and is unresponsive to an engine speed error with respect to an engine speed target.