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:
Dec. 26, 1978
Filed:
Jun. 10, 1977
John S Ivey, Bloomfield Hills, MI (US);
Alan L Miller, Mount Prospect, IL (US);
Borg-Warner Corporation, Chicago, IL (US);
Abstract
A control system to change gear ratio in an automatic transmission through friction elements engaged by hydraulic pressure. A closed loop electrical circuit is completed between a transducer, which provides an electrical signal related to the output torque of the transmission, and a pair of control valves, to vary the pressure applied to a friction element by each control valve. A circuit for computing reaction torque is coupled between the transducer and a logic control circuit, which provides logic command signals for controlling operation of components in the closed loop circuit. The system computes an output torque ramp when a downshift is called for by the shift point computer and uses controllers which react oppositely to control engagement of a clutch and brake in response to error signals of torque output compared to a desired ramp to produce a proper shift.