Patent ID: 6736757
Filing Date: 2004-05-18
Classification: F16H,Y10S,Y10T

Abstract:
A speed shift control apparatus for an automatic transmission, comprising an input shaft which receives power from an engine output shaft, an output shaft operatively connected to a wheel, a plurality of friction engagement elements selectively engaged to change a power transfer path between the input shaft and the output shaft; and hydraulic servos that engage and disengage the friction engagement elements, said control apparatus comprising:a controller that receives input signals from sensors based on vehicle running conditions and that outputs oil pressure control signals, said controller comprising: control means for controlling the oil pressure to the hydraulic servos operating friction engagement elements for a downshift to a predetermined speed stage, responsive to a downshift command; and downshift type determining means for determining whether the downshift should be a downshift type oriented toward minimum shock or a response-critical downshift type oriented toward responsiveness, based on a detected degree of throttle opening and a detected speed of accelerator pedal depression, a memory containing a map correlating pressure release gradients with degree of throttle opening and detected speed of accelerator depression and wherein said downshift type determining means determines the type of downshift by applying the detected degree of throttle opening and detected speed of accelerator pedal depression to said map, and wherein the control means controls the oil pressure of the hydraulic servos for the friction engagement elements based on the downshift type determined by the downshift type determining means.