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

摘要

The hydraulic pressure control valve regulates the operational pressure in response to a control force. The operational pressure is applied to the hydraulic clutch. The operational timings of the control valve is adjusted by control means in response to a detection of a condition immediately before engagement of the hydraulic clutch. The control 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.