25.25.
Electronic Transmission Control
The potential of electronics for enhanced control of semi and fully automatic transmissions has long been realized. Many transmission manufacturers, including AP (in the UK). ZF (in Germany), and Renault (in France) and, naturally, the US car makers, were experimenting with electrohydraulic transmission controls as early as the mid 1960s. These early analogue systems had no processing power but simply used transistors to switch current to solenoid valves and actuators on the transmission casing. The first such system to enter series production was available on a 1968 model Renault, Toyota and Nissan soon followed with their own version in 1970. Since they were expensive and offered only few advantages to the driver they failed to gain popularity.
The arrival of microcomputers enabled much more sophisticated control of automatic transmissions and Toyota introduced one of the first computer controlled automatic gearboxes on their 1982 model cars. In 1983 the evolution of power train electronic control system was continued in Europe when Bosch announced their Motronic system, which incorporates both engine and transmission control in one unit.
Today, sophisticated microprocessor control is a standard feature of almost all passenger car automatic transmission, including those using CVTs. Additionally the first truly driver-friendly semi-automatic transmission have now been made possible.
