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:
May. 30, 1989
Filed:
Mar. 06, 1987
Keiichi Yamamoto, Okazaki, JP;
Kazuo Ishikawa, Hoi, JP;
Aisin Seiki Kabushiki Kaisha, Aichi, JP;
Abstract
An automatic transmission includes a torque converter with a directly coupled clutch. A plurality of rotational speed sensors are used in the control of a lockup and a shifting operation. The invention provides an arrangement to detect any abnormality associated with such sensors. Under the lockup condition of the torque converter, a speed Ve detected by an engine rotational speed sensor, and speeds Vsp1 and Vsp2 detected by a first and a second vehicle speed sensor and a speed ratio K.sub.1 of a change gearing are used to detect any abnormality associated with the three sensors. All of the sensors are determined to be properly functioning when the equalities Ve=K.sub.1 .multidot.Vsp1 and Ve=K.sub.1 .multidot.Vsp2 apply. The first vehicle speed sensor is determined to be faulty when the former equation applies while the latter equation does not apply, and the second vehicle speed sensor is determined to be faulty when the former equality applies while the latter does not apply. When the both equalities do not hold, the engine rotational speed sensor is determined to be faulty.