Engine idling speed control signal generator

摘要

The idle speed of an engine is controlled in response to a control signal derived from the voltage across a thermistor responsive to the temperature of the engine cooling water. The thermistor voltage level varies exponentially with temperature changes. An engine idle speed control signal generator circuit includes a network of resistors, diodes and a transistor which produces an output control signal whose maximum level is limited to a value corresponding to a desired maximum idle speed, and whose minimum level is maintained above a value corresponding to the minimum desired idling speed. The circuit also adjusts the level of the output control signal to compensate for varying engine loads and faults in the circuit.