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:
Apr. 09, 1996
Filed:
Jul. 08, 1994
Takeshi Inuzuka, Anjo, JP;
Masashi Hattori, Anjo, JP;
Yasuo Hojo, Nagoya, JP;
Kunihiro Iwatsuki, Toyota, JP;
Shinji Kasuga, Anjo, JP;
Aisin Aw Co., Ltd., , JP;
Abstract
A lockup clutch of an automatic transmission is controlled so that no shock is produced while the vehicle is running within a predetermined gear stage. The automatic transmission includes a fluid coupling; a lockup clutch provided in the fluid coupling; a shift selector for selecting a range; a vehicle speed sensor for detecting vehicle speed, and a throttle opening sensor for detecting throttle opening. A control unit determines a gear stage in accordance with the selected range, the vehicle speed and the throttle opening, decides a shift, produces a shifting output signal, decides ON or OFF for the lockup clutch in accordance with the selected range, the vehicle speed and the throttle opening, and produces a lockup ON/OFF output signal. An oil pressure circuit actuates solenoid valves in response to the shifting output signal and the lockup ON/OFF output signal of the control unit. The solenoid valves, in turn, control engagement and release of frictional engagement elements to achieve the decided gear stage and control engagement and release of the lockup clutch. The control unit includes, stored in memory, a lockup diagram set with an ON/OFF hysteresis area; a comparator for deciding whether or not the vehicle speed and the throttle opening, at the time of a shifting output signal is produced, are within the ON/OFF hysteresis area of the lockup diagram; and a lockup output signal generator for turning the lockup output ON if the vehicle speed and the throttle opening are within the ON/OFF hysteresis area when the shifting output signal is produced.