JPS6415559A - Control device and returning device for coasting of automatic transmission of vehicle - Google Patents

Abstract

PURPOSE:To reduce a gear change shock at the time of down shift by providing each detecting means of whether a vehicle is in a casting condition, whether a vehicle speed is in a specific zone and whether a drive range condition is under way as well as a means of switching over a speed change map. CONSTITUTION:When the coasting condition of a vehicle and the establishment of a condition that the vehicle speed is in a specific range, etc., are detected, together with the detection, a speed change point is determined based on a vehicle speed map which is previously provided for an L-range. As a result, a second-to-first gear down-shift command is outputted at the same time the condition is established. And, based on this command, the oil pressure of a friction engaging device is drained and the gear change from the second gear stage to the first gear stage is carried out. Both at the points of time of the start and the end of this gear change period, there is little difference in rotating speed between an engine and a turbine, maintaining the coasting condition of a vehicle at both points of time. After a while, even if the driving condition of the first gear stage is started, the rotating speed of the turbine continues to be lowered as it is without repeated reverse rotation.