Microcomputer electronic control system for automatic transmission of motor vehicle

摘要

An electronic system for controlling the drive ratio changes in an automatic transmission of a motor vehicle having solenoid valves for actuating the gear changes. A microcomputer selectively governs the solenoid valves through power amplifiers, in such a way that when the solenoid valves are not energized the highest drive ratio is engaged. The ratio of the power amplifiers to the corresponding output signals of the microcomputer is such that the solenoid valves are not energized when the supply voltage is zero or when the microcomputer voltage drops below the threshold value necessary for its proper operation.