ELECTRONIC AND HYDRAULIC CONTROL SYSTEM FOR AUTOMATIC GEAR CHANGE TRANSMISSION

摘要

A manual selector valve, whose setting is controlled by the vehicle operator, distributes flow from a fluid pump to an ON-OFF valve and to a hydraulic clutch which on being engaged disposes the transmission for forward drive. Two ON-OFF valves act as pressure distributors and enable the manual valve to overrule the operation of the automatic shift valves. The state of two solenoid-actuated valves is determined by an electrical signal received from a microprocessor that receives operational information and has stored within its memory logic that controls the signals. If the electronic control system should fail, the state of the solenoid valves is determined hydraulically and mechanically thus permitting complete functional response as the operator manually displaces the selector valve. A variable force solenoid actuates a line pressure regulator valve, which cooperates with a solenoid pressure regulator valve to reduce line pressure. A pressure modulator valve directs manual valve outlet flow to the solenoid valves, which function as shift valves.