METHOD OF CONTROLLING SPEED RANGE SHIFTING IN AN AUTOMATIC TRANSMISSION

摘要

In a method of controlling speed range shifting, an input-output speed ratio (= output speed/input speed) in a shifting means by which a power transmitting route for the pre-shift speed range is selected is detected when a shift signal to shift from a speed range in which engine brake is available to another speed range in which engine brake is also available is transmitted. An intermediate power transmitting route in which engine brake is not available is selected after the transmission of a shift signal as long as the change of the speed ratio is within a specified range. Then, a power transmitting route for the post-shift speed range is selected based on the shift signal when the change in the speed ratio becomes bigger than the specified range.