End of fill detector for a fluid actuated clutch

• US 5,950,789 A
• Filed: 04/27/1998
• Issued: 09/14/1999
• Est. Priority Date: 04/27/1998
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Hosseini, Javad, Harrell, Kendall R., Stahl, Alan L.
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): RODRIGUEZ, SAUL
• Application Number:
  US09/066,969
• Time in Patent Office: 505 Days
• Field of Search: 192/85 R, 192/109 F, 192/103 F, 192/3.3, 192/3.31, 192/3.29, 192/3.58, 74/733.1
• US Class Current: 192/85.01
• CPC Class Codes: B60W 2050/0052 Filtering, filters
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: F16D 2500/30406 Clutch slip
• CPC Class Codes: F16D 2500/30415 Speed of the input shaft
• CPC Class Codes: F16D 2500/30426 Speed of the output shaft
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/30806 Engaged transmission ratio
• CPC Class Codes: F16D 2500/31413 Clutch pedal position
• CPC Class Codes: F16D 2500/3166 Detection of an elapsed period of time
• CPC Class Codes: F16D 2500/5014 Filling the actuator cylinder with fluid
• CPC Class Codes: F16D 2500/70668 Signal filtering
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 2061/062 for controlling filling of clutches or brake servos, e.g. fill time, fill level or pressure during filling

Abstract

In one aspect of this invention, a fluid actuated clutch is disclosed. The fluid actuated clutch is operatively connected to a control valve that is activated by an electronic controller that receives a signal from an input mechanism. The system and method includes detecting an instantaneous clutch slip and detecting when the instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor. This condition represents the end-of-fill point for the fluid actuated clutch.

Claims

1. A system for detecting an end-of-fill condition for a fluid actuated clutch comprising:

a fluid actuated clutch;

an input mechanism that generates a signal, including a value for an input speed of said fluid actuated clutch and a value of output speed for said fluid actuated clutch;

an electronic controller for detecting an instantaneous clutch slip, which is a difference between said input speed of said fluid actuated clutch and said output speed of said fluid actuated clutch and detecting when said instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor, where this condition represents the end-of-fill point for said fluid actuated clutch; and

a control valve that is activated by said electronic controller and said control valve is operatively connected to said fluid actuated clutch.

2. The system of claim 1, wherein said average of a predetermined number of cycles of instantaneous clutch slip is determined by a digital low pass filter.

3. The system of claim 1, wherein said predetermined factor is a fixed percentage of said average of a predetermined number of cycles of instantaneous clutch slip.

4. The system of claim 1, wherein said electronic controller determines if a preselected gear is engaged.

5. The system of claim 1, wherein said electronic controller determines if said speed of said engine drive exceeds a predetermined minimum value.

6. The system of claim 1, wherein said electronic controller determines if said end-of-fill point does not exceed a predetermined time period.

7. The system of claim 1, wherein said electronic controller determines if said end-of-fill point does not exceed a summation of pulse time, ramp time, hold time, and modulation times.

8. The system of claim 1, wherein said electronic controller determines if said instantaneous clutch slip does decrease over a plurality of cycles.

9. The system of claim 1, wherein said fluid actuated clutch is a lock-up clutch and said input mechanism generates a signal, including a value for speed of an engine drive and a value of output speed for a torque converter and said instantaneous clutch slip is a difference between said speed of said engine drive and said output speed of said torque converter.

10. The system of claim 9, wherein said electronic controller determines if said end-of-fill point does not exceed a predetermined time period.

11. A method for detecting an end-of-fill condition for a fluid actuated clutch, which is operatively connected to a control valve that is activated by an electronic controller that also receives a signal from an input mechanism, including a value for an input speed of said fluid actuated clutch and a value of output speed for said fluid actuated clutch, the method comprising the steps of:

detecting an instantaneous clutch slip, which is a difference between said input speed of said fluid actuated clutch and said output speed of said fluid actuated clutch; and

detecting when said instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor, where this condition represents the end-of-fill point for said fluid actuated clutch.

12. The method of claim 11, wherein said step of detecting when said instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor includes determining said average of a predetermined number of cycles of instantaneous clutch slip with a digital low pass filter.

13. The method of claim 11, wherein said step of detecting when said instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor includes determining said predetermined factor as a fixed percentage of said instantaneous clutch slip.

14. The method of claim 11, wherein said step of detecting an instantaneous clutch slip includes the step of determining if a preselected gear is engaged.

15. The method of claim 11, wherein said step of detecting an instantaneous clutch slip includes the step of determining if said speed of said engine drive exceeds a predetermined minimum value.

16. The method of claim 11, wherein said step of detecting when said instantaneous clutch slip is less than an average includes the step of determining if said end-of-fill point does not exceed a predetermined time period.

17. The method of claim 11, wherein said step of detecting when said instantaneous clutch slip is less than an average includes the step of determining if said end-of-fill point does not exceed a summation of pulse time, ramp time, hold time, and modulation times.

18. The method of claim 11, wherein said step of detecting when said instantaneous clutch slip is less than an average includes the step of determining if said instantaneous clutch slip does decrease over a plurality of cycles.

19. The method of claim 11, wherein said fluid actuated clutch is a lock-up clutch and said input mechanism generates a signal, including a value for speed of an engine drive and a value of output speed for a torque converter and said instantaneous clutch slip is a difference between said speed of said engine drive and said output speed of said torque converter.

20. The method of claim 19, wherein said step of detecting an instantaneous clutch slip includes the step of determining if said speed of said engine drive exceeds a predetermined minimum value.