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. 10, 1991
Filed:
Dec. 26, 1989
Carl A Lentz, Mooresville, IN (US);
Jeffrey K Runde, Indianapolis, IN (US);
Joseph H Hunter, Carmel, IN (US);
Christopher R Wiles, Indianapolis, IN (US);
General Motors Corporation, Detroit, MI (US);
Abstract
In an automatic transmission upshifting is controlled by ramping down the pressure in an off-going clutch associated with a high speed ratio and increasing the pressure in an on-coming clutch associated with a lower speed ratio. The on-coming clutch has commanded pressure at a maximum value for an initial fill time, a lower increasing ramp value during the ramp of the off-going clutch until the on-coming clutch starts to engage, and then a closed-loop control until the clutch reaches a synchronous speed. The closed-loop control parameter is on-coming clutch slip which is controlled to a calculated slip speed profile. Parameters for controlling the quality of a shift such as on-coming clutch initial pressure, off-going clutch initial pressure and on-coming clutch fill time are automatically adjustable during vehicle use to correct shift aberrations which degrade shift quality. A fast adjustment mode is in effect initially to calibrate the transmission control for the engine and vehicle. After a smooth shift is obtained only small adjustments are allowed.