Controlling the operating states of a torque converter clutch in an automatic transmission

• US 20080254941A1
• Filed: 04/11/2007
• Published: 10/16/2008
• Est. Priority Date: 04/11/2007
• Status: Abandoned Application

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Cecil, Douglas R., Scott, Jeffery, Gallo, Joseph J.
• Application Number:
  US11/786,296
• Publication Number:
  US 20080254941A1
• Time in Patent Office: Days
• US Class Current: 477/169
• CPC Class Codes: F16H 59/58 dependent on signals from the steering
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/143 using electric control means

Abstract

A method for controlling a torque converter clutch in an automatic transmission of a vehicle that includes an engine, an accelerator pedal and wheels, the converter clutch alternately connecting and disconnecting the engine and transmission when the clutch is engaged and disengaged. The method includes determining that the vehicle is either ascending a grade or operating in a loaded condition, determining that the clutch is engaged, determining whether the vehicle is operating in a curve, preventing disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and the vehicle is operating in a curve, and allowing disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition.

Claims

1. A method for controlling a torque converter clutch in an automatic transmission of a vehicle that includes an engine, an accelerator pedal and wheels, the converter clutch alternately connecting and disconnecting the engine and transmission when the clutch is engaged and disengaged, the method comprising the steps of:

(a) determining that the vehicle is either ascending a grade or operating in a loaded condition;

(b) determining that the clutch is engaged;

(c) determining whether the vehicle is operating in a curve;

(d) preventing disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and the vehicle is operating in a curve;

(e) allowing disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition.

2. The method of claim 1, further comprising:

(f) monitoring movement of the accelerator pedal to determine the occurrence of a closed accelerator pedal; and

wherein step (d) further comprises preventing disengagement of the clutch if the accelerator pedal is closed.

3. The method of claim 1, further comprising:

(f) monitoring movement of accelerator pedal to determine the occurrence of a closed accelerator pedal; and

determining the length of a predetermined period that begins upon engaging the clutch; and

wherein step (e) further comprises allowing disengagement of the clutch if the accelerator pedal is closed and the predetermined period has expired.

4. The method of claim 1, wherein:

step (c) further comprises using a speed of the wheels at opposite lateral sides of an axle to determining a current vehicle lateral acceleration; and

step (d) further comprises;

determining a reference vehicle lateral acceleration; and

preventing disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and if the vehicle lateral acceleration is greater than the reference vehicle lateral acceleration.

5. The method of claim 1, wherein:

step (c) further comprises determining a current vehicle lateral acceleration from

${\left(\mathrm{VS}\right)}^2<br><br>\frac{\left(2\right)}{\left(T\right)}<br><br>\frac{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A-\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A+\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}$

wherein VS is a speed of the vehicle, wheel speed A is a speed of a wheel at a first side of an axle, wheel speed B is a speed of a wheel at a second side of an axle opposite the first side, and T is a dimension of a track of the axle;

step (d) further comprises;

determining a reference vehicle lateral acceleration; and

preventing disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and if the current vehicle lateral acceleration is greater than the reference vehicle lateral acceleration.

6. The method of claim 1, wherein:

step (c) further comprises using a speed of the wheels at opposite lateral sides of an axle to determining a current vehicle lateral acceleration; and

step (e) further comprises;

determining a reference vehicle lateral acceleration; and

allowing disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition and if the vehicle lateral acceleration is less than the reference lateral acceleration.

7. The method of claim 1, wherein:

step (c) further comprises determining a current vehicle lateral acceleration from

${\left(\mathrm{VS}\right)}^2<br><br>\frac{\left(2\right)}{\left(T\right)}<br><br>\frac{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A-\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A+\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}$

wherein VS is a speed of the vehicle, wheel speed A is a speed of a wheel at a first side of an axle, wheel speed B is a speed of a wheel at a second side of an axle opposite the first side, and T is a dimension of a track of the axle;

step (e) further comprises;

determining a reference vehicle lateral acceleration; and

allowing disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition and if the vehicle lateral acceleration is less than the reference lateral acceleration.

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

determining a current position of the accelerator pedal;

determining a current vehicle acceleration;

determining a reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal;

comparing the current vehicle acceleration to the reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal; and

determining that the vehicle is either ascending a grade or operating in a loaded condition if the current vehicle acceleration is less than the reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal.

9. A system for controlling a torque converter in an automatic transmission of a vehicle that includes an engine and transmission, the system comprising:

a torque converter clutch alternately connecting and disconnecting the engine and transmission when the clutch is engaged and disengaged, respectively;

an accelerator pedal for at least partially controlling operation of the engine;

an accelerator pedal sensor producing a signal representing a position of the accelerator pedal;

a controller in communication with the transmission, the engine, the clutch, and the accelerator pedal sensor, the controller being configured to determine that the vehicle is either ascending a grade or operating in a loaded condition, determine that the clutch is engaged, determine whether the vehicle is operating in a curve, prevent disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and the vehicle is operating in a curve, and allow disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition.

10. The system of claim 9, wherein the controller is further configured to monitor the signal produced by the accelerator pedal sensor to determine the occurrence of a closed accelerator pedal, and to prevent disengagement of the clutch if the accelerator pedal is closed.

11. The system of claim 9, further comprising:

a timer for measuring the length of a predetermined period that begins upon engaging of the clutch; and

wherein the controller is further configured to monitor the signal produced by the accelerator pedal sensor to determine the occurrence of a closed accelerator pedal, determine whether the timer is expired, and allow disengagement of the clutch if the accelerator pedal is closed and the timer is expired.

12. The system of claim 9, further comprising:

first and second wheels, each wheel located at an opposite lateral side of an axle; and

wherein the controller is further configured to use a speed of the first and second wheels to determine a current vehicle lateral acceleration, determine a reference vehicle lateral acceleration, and prevent disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and if the vehicle lateral acceleration is greater than the reference vehicle lateral acceleration.

13. The system of claim 9, further comprising:

first and second wheels, each wheel located at an opposite lateral side of an axle; and

wherein the controller is further configured to determine a current vehicle lateral acceleration from

${\left(\mathrm{VS}\right)}^2<br><br>\frac{\left(2\right)}{\left(T\right)}<br><br>\frac{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A-\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A+\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}$

wherein VS is a speed of the vehicle, wheel speed A is a speed of the first wheel, wheel speed B is a speed of the second wheel, and T is a dimension of a track of the axle, determine a reference vehicle lateral acceleration, and prevent disengagement of the clutch if the vehicle is either ascending a grade or operating in a loaded condition and if the current vehicle lateral acceleration is greater than the reference vehicle lateral acceleration.

14. The system of claim 9, further comprising:

first and second wheels, each wheel located at an opposite lateral side of an axle; and

wherein the controller is further configured to determine a current vehicle lateral acceleration from

${\left(\mathrm{VS}\right)}^2<br><br>\frac{\left(2\right)}{\left(T\right)}<br><br>\frac{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A-\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}{\left(\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>A+\mathrm{wheel}<br><br><br><br>\mathrm{speed}<br><br><br><br>B\right)}$

wherein VS is a speed of the vehicle, wheel speed A is a speed of the first wheel, wheel speed B is a speed of the second wheel, and T is a dimension of a track of the axle, determine a reference vehicle lateral acceleration, and allowing disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition and if the vehicle lateral acceleration is less than the reference lateral acceleration.

15. The system of claim 9, further comprising:

first and second wheels, each wheel located at an opposite lateral side of an axle; and

wherein the controller is further configured to use a speed of the first and second wheels to determine a reference vehicle lateral acceleration, and allow disengagement of the clutch if the vehicle is neither ascending a grade nor operating in a loaded condition and if the vehicle lateral acceleration is less than the reference lateral acceleration.

16. The system of claim 9, wherein the controller is further configured to determine a current position of the accelerator pedal, determine a current vehicle acceleration, determine a reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal, compare the current vehicle acceleration to the reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal, and determine that the vehicle is either ascending a grade or operating in a loaded condition if the current vehicle acceleration is less than the reference magnitude of vehicle acceleration that corresponds to the current position of the accelerator pedal.