HYDRAULIC PRESSURE CONTROL SYSTEM OF AUTOMATIC TRANSMISSION FOR CAR

摘要

PURPOSE: A hydraulic pressure control system of an automatic transmission for a car is provided to effectively prevent damage and breakage of a power train due to simultaneous operation of a second clutch and a first brake. CONSTITUTION: A hydraulic pressure control system of an automatic transmission for a car includes a switch valve. The switch valve holds one control pressure in common when an engine brake friction element for stopping a function of a one-way clutch and another friction element are controlled. During a forward traveling, the system connects control pressure to the engine brake friction element only when conditions of engine brake signal pressure and solenoid pressure according to a position change of a manual valve are satisfied. If not, the system connects control pressure to the other friction element. In another traveling condition excepting the forward traveling, the system connects control pressure to the engine brake friction element.