Belt replacement timing annunciator for belt-type automatic transmissions

A belt replacement timing annunciator for an automatic transmission mounted on a vehicle provided with an endless belt routed between a drive pulley connected to an output shaft of an engine and a driven pulley connected to an axle of a driving wheel, wherein a change gear ratio is shifted by changing radii of the endless belt according to operating conditions of the vehicle, said annunciator comprising:

• an electronic control unit;
• a pair of revolution sensors providing a number of output shaft revolutions signals and a vehicle velocity signal;
• a throttle valve opening sensor for recording a degree of throttle valve opening signal;
• a microcomputer, said microcomputer processing said signals from said sensors, recording an integrated mileage value L, calculating an actual change gear ratio and comparing said actual obtain a change gear ratio determination value;
• change gear ratio to a predetermined reference change gear ratio to
• an LED display for indicating a belt replacement signal when said actual change gear ratio differs from said predetermined reference change gear ratio;
• and
• a resetting device for clearing a belt replacement signal based upon an operator input.