The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Apr. 12, 1994

Filed:

Feb. 11, 1993
Applicant:
Inventors:

Yuichi Tanaka, West Bloom Field, MI (US);

Yasuhiro Nakajima, Kyoto, JP;

Toshitaka Naruse, Kyoto, JP;

Katsuhiro Hatta, Kyoto, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16H / ;
U.S. Cl.
CPC ...
74866 ;
Abstract

A shift control method for an automatic transmission of an automotive vehicle comprises a preliminary stage which is executed for eliminating the play in mechanism of a low/reverse brake of the automatic transmission at a shifting, particularly at a shifting of the transmission from the neutral position to a running position when the vehicle is at rest, and an engagement stage which is executed subsequently to the preliminary stage for operating the brake substantially. In the preliminary and engagement stages, the fluid pressure supplied to the brake is controlled in accordance with the precontrol pattern and the main control pattern, respectively. The shift control method further comprises a step of correcting a factor defining the precontrol pattern such that the time required from the start of the engagement stage to the start of a substantial shifting of the automatic transmission coincides with an ideal reference time, and a step of correcting the initial value of the fluid pressure supplied to the engaging element at the start of the main control pattern such that the rate of change in the rotational speed of the input shaft of the transmission during the period from the start of the substantial shifting to the end of same coincides with an ideal reference rate.


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