Speed change control method for setting a gearshift position of an automatic transmission for vehicles based upon driver acceleration intention and external variables

摘要

When a vehicle is traveling on a descending slope, the gearshift position of an automatic transmission is set to a position selected in accordance with driver's intention to accelerate the vehicle based on the accelerator opening. A decision is preferably made as to whether the gearshift position should be set to a low-speed gearshift position where an engine brake can be applied, in accordance with the magnitude comparison between a threshold value and at least one value of a gradient of a road and a timedependent change in vehicle speed. The threshold value may be changed to a value that causes the low-speed gearshift position to be easily selected if the frictional resistance of the road surface is judged to be low. Further, the threshold value may be preset corresponding to the degree of gradient and/or winding of the road. Further, the threshold value is changed to a value that causes the low-speed gearshift position to be easily selected if the detected operating amount of braking exceeds a predetermined standard value.