Granted Patent B2

US 7,693,635 · App. 11/386,137 · Granted Apr 6, 2010

Abstract

Claims (40)

1. A method for approximating the flow rate of hydraulic fluid in an automatic transmission comprising:

estimating a flow rate value for each of a plurality of temperatures;

measuring a current transmission temperature; and

learning the flow rate corresponding to the current transmission temperature, said learning including:

identifying a presence of a predefined shift aberration;

iteratively adjusting the flow rate estimation corresponding to the current transmission temperature if the predefined shift aberration was not identified; and

altering the flow rate estimation corresponding to the current transmission temperature by one iterative step if the predefined shift aberration was identified, said altered flow rate estimation representing the learned flow rate value for the current transmission temperature.

2. The method of claim 1 , wherein said learning the flow rate is performed only after a completion of a shift from which the flow rate is to be learned.

3. The method of claim 2 , wherein said learning the flow rate is performed only if the measured transmission temperature is outside a predefined normal operating temperature range.

4. The method of claim 3 , wherein said learning the flow rate is performed only if the completed shift occurred at a normal shift point.

5. The method of claim 4 , wherein said learning the flow rate is performed only if a maximum engine speed during the shift from which the flow rate is to be learned was less than a predefined engine speed value.

6. The method of claim 4 , wherein said learning the flow rate is performed only if a transmission pump speed is adequate to regulate pressure.

7. The method of claim 4 , further comprising storing said learned flow rate value into a non-volatile memory device.

8. The method of claim 4 , further comprising decreasing the iterative step after the flow rate value has been learned.

9. A method for approximating the flow rate of hydraulic fluid in an automatic transmission comprising:

estimating a flow rate value for each of a plurality of temperatures;

measuring a current transmission temperature;

learning the flow rate corresponding to the current transmission temperature, said learning including:

identifying a presence of an engine flare condition;

iteratively increasing the flow rate estimation corresponding to the current transmission temperature if the engine flare condition was not identified; and

reducing the flow rate estimation corresponding to the current transmission temperature by one iterative step if the engine flare condition was identified, said reduced flow rate estimation representing the learned flow rate value for the current transmission temperature; and

storing the learned flow rate value for the current transmission temperature in a non-volatile memory device.

10. The method of claim 9 , wherein said learning the flow rate is performed only after a completion of an upshift from which the flow rate is to be learned.

11. The method of claim 10 , wherein said learning the flow rate is performed only if the measured transmission temperature is outside a predefined normal operating temperature range.

12. The method of claim 11 , wherein said learning the flow rate is performed only if a minimum engine throttle during a preceding upshift is greater than a predetermined amount.

13. The method of claim 12 , wherein said learning the flow rate is performed only if the preceding upshift occurred at a normal shift point.

14. The method of claim 13 , wherein said learning the flow rate is performed only if a maximum engine speed during the preceding upshift was less than a predefined engine speed value.

15. A method for approximating the flow rate of hydraulic fluid in an automatic transmission comprising:

estimating a flow rate value for each of a plurality of temperatures;

measuring a current transmission temperature;

learning the flow rate corresponding to the current transmission temperature, said learning including:

identifying a presence of an overfill condition;

iteratively decreasing the flow rate estimation corresponding to the current transmission temperature if the overfill condition was not identified; and

increasing the flow rate estimation corresponding to the current transmission temperature by one iterative step if the overfill condition was identified, said increased flow rate estimation representing the learned flow rate value for the current transmission temperature; and

storing the learned flow rate value for the current transmission temperature in a non-volatile memory device.

16. The method of claim 15 , wherein said learning the flow rate is performed only after a completion of a regulated closed-throttle downshift or a regulated garage shift.

17. The method of claim 16 , wherein said learning the flow rate is performed only if the measured transmission temperature is outside a predefined normal operating temperature range.

18. The method of claim 17 , wherein said learning the flow rate is performed only if the preceding regulated closed-throttle downshift or regulated garage shift occurred at a normal shift point.

19. The method of claim 18 , wherein said learning the flow rate is performed only if a transmission pump speed is adequate to regulate pressure.

20. The method of claim 19 , further comprising decreasing the iterative step after the flow rate value has been learned.

Assignments (13)