Automatic gearbox for a car

摘要

An automatic gearbox of a vehicle has the gear ratio shifted according to the movement of the throttle flap in the engine intake. There is a unit to evaluate the frequency of direction change of the flap in a given time period and the gear shifting also depends on this frequency. The sensor measuring throttle angle outputs a signal to a differentiator to measure rate of change of throttle angle, followed by a low-pass filter. This results in a signal which is passed to a fuzzy logic circuit which decides whether an "economic" or so- called "sporty" gear shift characteristic is needed.