APPARATUS FOR AND METHOD OF CONTROLLING HYDRAULIC CLUTCH OPERATION IN AN AUTOMATIC TRANSMISSION

摘要

A hydraulic pressure control valve (56) regulates the operational pressure in response to a valve operating force. The operational pressure is applied to the hydraulic clutch (12c, 13c, 14c). The operational timing of the control valve is adjusted by control means (80,82.84) in response to a detection of a condition immediately before engagement of the hydraulic clutch. The operating force is set to maximum at first during shifting. It is reduced to a low value when the above condition is detected so that the operational hydraulic pressure is reduced to a pressure a little lower than engagement starting pressure at which the hydraulic clutch is kept in a condition immediately before engagement. Then, it is increased to a specified value when an input to output speed ratio becomes approximately 1.0 so that the operational hydraulic pressure is increased to a specified pressure at which the hydraulic clutch is engaged.