Power off upshift control method for automatic transmission

• US 6,634,989 B2
• Filed: 12/28/2000
• Issued: 10/21/2003
• Est. Priority Date: 12/30/1999
• Status: Expired due to Fees

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Yu, Pyung-Hwan
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US09/749,559
• Publication Number:
  US 20010007844A1
• Time in Patent Office: 1,027 Days
• Field of Search: 477/143, 477/148, 477/154, 477/156, 477/158, 477/120
• US Class Current: 477/143
• CPC Class Codes: F16H 2059/385 Turbine speed
• CPC Class Codes: F16H 2059/425 Rate of change of input or turbine shaft speed
• CPC Class Codes: F16H 2061/0087 Adaptive control, e.g. the control parameters adapted by learning
• CPC Class Codes: F16H 2061/0255 Solenoid valve using PWM or duty-cycle control
• CPC Class Codes: F16H 2061/0496 for low engine torque, e.g. during coasting, sailing or engine braking
• CPC Class Codes: F16H 59/22 Idle position
• CPC Class Codes: F16H 61/0437 by using electrical signals F16H61/0403 and F16H61/061 take precedence

Abstract

A power Off upshift control method for an automatic transmission includes the steps of: a) determining if a vehicle is under conditions requiring power Off upshift control; b) starting power Off upshift duty control if the conditions are satisfied; c) calculating average turbine rpm change rate; d) measuring turbine rpm changing period and determining if the turbine rpm changing period is greater than a predetermined value; e) calculating a shift finish point if the turbine rpm changing period is greater than the predetermined value; f) determining if the turbine rpm change rate is less than a value obtained by adding a mapping value to the turbine rpm change rate; g) determining if the turbine rpm value is greater than or equal to the shift finish point, if the turbine rpm change rate is greater than the mapped value in the previous step; h) producing a shift finish point duty rate if the turbine rpm value is greater than or equal to the shift finish point; i) determining if the turbine rpm is less than a target turbine rpm; j) ending duty control if the turbine rpm is less than the target turbine rpm; k) determining if the turbine rpm is less than the a value obtained by subtracting 100 rpm from the target turbine rpm; and l) compensating duty rate and learn the duty rate if the turbine rpm is less than the subtracted value in the previous step.

Claims

1. A power Off upshift control method for an automatic transmission comprising the steps of:

a) determining if a vehicle is under conditions requiring power Off upshift control;

b) starting power Off upshift duty control if the conditions are satisfied;

c) calculating average turbine rpm change rate;

d) measuring turbine rpm changing period and determining if the turbine rpm changing period is greater than a target fill time;

e) calculating a shift finish point if the turbine rpm changing period is greater than the predetermined value;

f) determining if the turbine rpm change rate is less than a value obtained by adding a mapping value to the turbine rpm change rate;

g) determining if the turbine rpm value is greater than or equal to the shift finish point rpm, if the turbine rpm change rate is greater than the mapped value in the previous step;

h) producing a shift finish point duty rate if the turbine rpm value is greater than or equal to the shift finish point;

i) determining if the turbine rpm is less than a target turbine rpm;

j) ending duty control if the turbine rpm is less than the target turbine rpm;

k) determining if the turbine rpm is less than the a value obtained by subtracting a predetermined value from the target turbine rpm; and

l) compensating duty rate and learn the duty rate if the turbine rpm is less than the subtracted value in the previous step.

2. A power Off upshift control method of claim 1 wherein the average turbine rpm change rate in step c) is obtained by dividing an arithmetic summation of turbine rpm change rates at several points in time.

3. A power Off upshift control method of claim 1 further comprises of the steps of:

determining if the turbine rpm change rate is less than a value obtained by adding a mapping value to the turbine rpm change rate, if the condition of the turbine rpm change period in step d) is not satisfied;

compensating for a beginning fill time and learning the compensated fill time if the turbine rpm change rate is less than a value obtained by adding a mapping value to the turbine rpm change rate; and

taking into the step g) without the fill time compensation if the turbine rpm change rate is greater than or equal to the value obtained by adding a mapping value to the turbine rpm change rate in the previous step.

4. A power Off upshift control method of claim 3 wherein the beginning fill time is obtained by subtracting compensated fill time from a present fill time.

5. A power Off upshift control method of claim 4 wherein the compensated fill time is set by mapping the present value to a value calculated by a predetermined program.

6. A power Off upshift control method of claim 1 wherein the shift finish point calculation is not performed if the condition of the turbine rpm change period in step d) is not satisfied.

7. A power Off upshift control method of claim 1 wherein the shift finish point is obtained by adding a value calculated by multiplying the average turbine rpm change rate by a hydraulic response time to the target turbine rpm.

8. A power Off upshift control method of claim 1 wherein duty compensation is performed and learned as determined a tie-up occurs if the condition of the turbine rpm change rate in step f) is satisfied.

9. A power Off upshift control method of claim 8 wherein the duty compensation value is obtained by subtracting a predetermined value from a present duty value.

10. A power Off upshift control method of claim 5 wherein the shift finish point calculation is not performed during the duty compensation.

11. A power Off upshift control method of claim 1 wherein the duty compensation is performed by adding a predetermined value to the present duty.

12. A power Off upshift control method of claim 11 wherein the predetermined value is 1% of the present duty.

13. A power Off upshift control method of claim 1, wherein the learning is performed only when all the following condition are satisfied.

During the power Off upshift.

When throttle opening is equal to or less than 0.65 v and the idle switch is on.

When the oil temperature is greater than 0°

C.

14. A power Off upshift control method of claim 1 wherein the learning is stopped if among the three conditions is not satisfied.

15. A power Off upshift control method of claim 1 wherein the learning is performed when the throttle opening is greater than 0.65 v or the oil temperature is equal to or less than 0°

C., if a value obtained by subtracting the target turbine rpm from the present turbine rpm is less than −

100.