Fuel control circuit for vehicle engines - reduces fuel flow at high revolution notes, if throttle is closed

摘要

When a motor-vehicle engine is operating at high speed, but the throttle is closed, as happens during braking, fuel is sucked into the carburettor and wasted. This circuit reduces the flow of fuel to a 'tick-over' min. when the accelerator pedal is not pressed, but the revolution rate is high. The vehicle ignition signal (2) is fed via a 0.25 second differentiator (1) to a comparator circuit (6) where the rate is compared (5) with a reference signal. If the throttle microswitch (11) is operated, i.e. no foot is on the pedal, the output amplifier (8, T1) operates a valve (9) reducing the fuel flow and lighting an LED (10) on the dashboard.