Patent ID: 6285942
Filing Date: 2001-09-04
Classification: F16H,Y10T

Abstract:
A control method for an automatic transmission including an on-coming clutch having an apply chamber that is filled with hydraulic fluid in a preparation phase of shifting, a pump for providing hydraulic fluid at a regulated pressure, and a controller for supplying hydraulic fluid at a commanded pressure to the on-coming clutch during the preparation phase, the method comprising the steps of:setting the commanded pressure to a determined fill pressure at an onset of the preparation phase;estimating a flow rate of the hydraulic fluid supplied to said on-coming clutch based on the determined fill pressure, a temperature of the fluid and a speed of the pump;integrating the estimated flow rate during the preparation phase to determine a cumulative volume of fluid supplied to said on-coming clutch; andsetting the commanded pressure to a determined post-fill pressure when the determined computed volume reaches a reference volume which is less than a volume of said apply chamber.