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.
Patent No.:
Date of Patent:
Aug. 29, 1995
Filed:
Aug. 12, 1993
Kenjiro Fujita, Kusatsu, JP;
Katsutoshi Usuki, Kyoto, JP;
Mitsubishi Jidosha Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A speed change control method and apparatus for a vehicular automatic transmission having a first-speed clutch for establishing a first speed and a second-speed clutch for establishing a second speed, includes subjection of at least a duty ratio Dr of a second-speed solenoid valve for supplying oil pressure to the second-speed clutch to feedback control, so that the first-speed clutch is engaged while disengaging the second-speed clutch. This thereby increases a turbine rotational speed Nt toward the first-speed synchronous rotational speed. Further, an upper limit value Dmax of the duty ratio Dr is set, and the duty ratio Dr is subject to feedback control within a resultant duty ratio range. This thereby prevents the duty ratio Dr from being set at an excessive value caused by a delay in the rise of the oil pressure. As a result, even if a depression of an accelerator pedal is suddenly increased during a downshifting process, an interlock problem can be prevented, thereby ensuring smooth speed change.