Patent Number: 8,788,159

Title: Transmission gear shift control

Abstract: A method for controlling pressure applied to a displaceable piston in a cylinder, piston displacement actuating a control element of an automatic transmission during a gearshift, includes determining whether piston displacement exceeds a free length of an isolation spring located between the piston and a friction plate of the control element; calculating the pressure using A the cross-sectional area of the piston; K a coefficient of a return spring extending between the piston and a reference position in the cylinder; x the piston displacement; F.sub.0 a pre-load of the return spring; x.sub.free the free length of the isolation spring; and K.sub.is a coefficient of the isolation spring; and applying the calculated pressure to the piston.

Inventors: Peitron; Gregory Michael (Canton, MI), Thornton; Sarah M. (Sacramento, CA), Yanakiev; Diana (Birmingham, MI), McCallum; James William Loch (Ann Arbor, MI), Annaswamy; Anuradha (W. Newton, MA)

Assignee: Ford Global Technologies, LLC

International Classification: G06F 7/00 (20060101); F16H 61/00 (20060101); G06F 17/00 (20060101); F16H 61/26 (20060101)

Expiration Date: 2022-07-22 0:00:00