Control of gear shifting in automatic transmission

• US 5,131,295 A
• Filed: 05/21/1991
• Issued: 07/21/1992
• Est. Priority Date: 05/22/1990
• Status: Expired due to Fees

• Current Assignee: JATCO Corp (Nissan Motor Co., Ltd.)
• Original Assignee: JATCO Corp (Nissan Motor Co., Ltd.)
• Inventors: Kodama, Mikio
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US07/703,788
• Time in Patent Office: 427 Days
• Field of Search: 74/862, 74/866
• US Class Current: 477/155
• CPC Class Codes: F16H 2059/6807 Status of gear-change operation, e.g. clutch fully engaged
• CPC Class Codes: F16H 2061/0096 using a parameter map
• CPC Class Codes: F16H 59/16 Dynamometric measurement of torque
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 61/08 Timing control

Abstract

In an automatic transmission of a motor vehicle, a torque of a transmission output member is detected, after the detected torque has dropped at a rate greater than a predetermined value after generation of a gear shifting command signal, a length of time elapsed thereafter is measured, a pressurized hydraulic fluid is modified as a predetermined function of the length of time measured, and a hydraulically actuable coupling is actuated by the modified pressurized hydraulic fluid.

Claims

1. A method of controlling an automatic transmission of a motor vehicle, wherein the automatic transmission has an output member, and effects a gear shifting by a hydraulically actuatable coupling by a pressurized hydraulic fluid, the method comprising the steps of:

detecting a torque of the output member and generating an output torque indicative signal indicative of said torque detected;

measuring a length of time elapsed after a rate of change of said output torque indicative signal has met a predetermined relationship with a predetermined value after generation of a gear shifting command signal and generating a time indicative signal indicative of said length of time elapsed;

modifying the pressurized hydraulic fluid as a predetermined function of said time indicative signal; and

actuating the hydraulically actuable coupling by said modified pressurized hydraulic fluid.

2. A method as claimed in claim 1, wherein said step of modifying the pressurized hydraulic fluid terminates upon an elapse of a predetermined length of time after an actual gear ratio has become substantially equal to a gear ratio to be established after the gear shifting.

3. A method as claimed in claim 1, wherein said step of modifying the pressurized hydraulic fluid terminates when said rate of change of said output torque indicative signal meets a predetermined relationship with a second predetermined value after a gear ratio has become substantially equal to a gear ratio to be established after the gear shifting.

4. A method as claimed in claim 1, wherein said step of measuring said length of time includes a step of determining said rate of change of said output torque indicative signal and a step of comparing said determined rate of change with said predetermined value.

5. A method as claimed in claim 1, wherein said step of modifying the pressurized hydraulic fluid includes a step of generating a correction signal as a function of said time indicative signal.

6. A system for controlling an automatic transmission of a motor vehicle, wherein the automatic transmission has an output member, and effects a gear shifting by a hydraulically actuatable coupling by a pressurized hydraulic fluid, the system comprising:

a torque sensor means for detecting a torque of the output member and generating an output torque indicative signal indicative of said torque detected; and

a control unit including,

means for measuring a length of time elapsed after a rate of change of said output torque indicative signal has met a predetermined relationship with a predetermined value after generation of a gear shifting command signal and generating a time indicative signal indicative of said length of time elapsed, and

means for generating a correction signal as a predetermined function of said time indicative signal;

means for modifying the pressurized hydraulic fluid in response to said correction signal; and

means for actuating the hydraulically actuable coupling by said modified pressurized hydraulic fluid.