Patent ID: 7905814
Filing Date: 2011-03-15
Classification: F16H,Y10T

Abstract:
1. A shift control method of an automatic transmission for controlling a shift from an n th shift speed, achieved by engagement of a first and a second frictional element, to an (n−3) th shift speed, achieved by engagement of a third and a fourth frictional element, the method comprising: (a) beginning a release control of the first frictional element; (b) beginning a release control of the second frictional element after step (a) and after the shift is determined to be completed; (c) beginning an engagement control of the third frictional element; and (d) beginning an engagement control of the fourth frictional element after step (c); and wherein reducing hydraulic pressure of the second frictional element to a neutral state is performed after step (b); and wherein the shift is determined to be completed when a predetermined shifting time has passed since a shift signal from the n