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:
Sep. 09, 2014
Filed:
Jul. 27, 2012
Todd J. Thor, Byron, MI (US);
Todd J. Thor, Byron, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A method of learning the return spring pressure of a clutch in a vehicle having an engine and an automatic transmission includes selecting a clutch for analysis from a plurality of clutches of the transmission when the vehicle coasts for a predetermined duration. The method includes ramping down clutch pressure to the selected clutch until engine speed reaches idle and measuring the clutch pressure for the selected clutch after engine speed has remained at idle for a calibrated duration. An actual return spring pressure may be calculated as a function of the preliminary return spring pressure. The actual return spring pressure may be used thereafter to control a subsequent shift event of the transmission. A vehicle includes an engine, transmission, and controller configured to detect a predetermined coasting condition, and to execute code using a processor to thereby execute the above method. A system includes the transmission and controller.