Patent ID: 6029107
Filing Date: 2000-02-22
Classification: F16H,Y10S,Y10T

Abstract:
A control apparatus for an automatic transmission of a vehicle, in which a gear ratio of the automatic transmission is controlled by changing a speed ratio between an input-side rotating member to which the driving force from an engine is transmitted and an output-side rotating member through which the driving force is transmitted to driven wheels, comprising:a vehicle speed detecting part for detecting the speed of the vehicle,road gradient estimating part for estimating a gradient of a road on which the vehicle is running,a road gradient determining part for determining if the road gradient estimated by a road gradient estimating part is beyond a predetermined threshold value,a vehicle speed determining part for determining a target vehicle speed based on vehicle speed detected by said vehicle speed detecting part, when it is determined by said gradient determining part that the road gradient is beyond the predetermined threshold value, anda control part for controlling the gear ratio so that the vehicle speed substantially matches the target vehicle speed determined by said vehicle speed determining part, when it is determined by said gradient determining part that the road gradient is beyond the predetermined threshold value,wherein said road gradient estimating part further comprises:a vehicle driving-torque calculating part for calculating the vehicle driving-torque to drive the driven wheels, output from the output-side rotating member,a running resistance calculating part for obtaining a running resistance torque based on the vehicle speed detected by said vehicle speed detecting part,an acceleration torque calculating part for obtaining acceleration of the vehicle, and calculating acceleration torque based on the obtained acceleration, anda gradient calculating part for obtaining a gradient torque, and calculating the road gradient based on the gradient torque obtained by subtracting the running resistance torque calculated by said running resistance calculating part and the acceleration torque calculated by said acceleration torque calculating part from the vehicle driving torque calculated by said vehicle driving-torque calculating part.