Ignition system — general description (Audi 100 C3)

Audi 100 vehicles use two types of ignition systems: a contactless transistor system on vehicles without turbocharging and an electronic system on vehicles with turbocharging.

The transistor system consists of an ignition distributor, ignition coil, ignition control unit, spark plugs and high and low voltage wires.

The ignition distributor pulse sensor operates on the Hall effect principle.

The ignition system has two electrical circuits: high and low voltage.

The high-voltage circuit consists of the high-voltage winding of the ignition coil, the distributor cap with the contact carbon, the distributor rotor, the spark plugs and the high-voltage wires, the low-voltage circuit consists of the ignition switch, the primary winding of the ignition coil and the pulse unit of the distributor, which generates signals for the control unit. The pulse unit, or Hall sensor, consists of a winding, a permanent magnet and a signal-generating microcircuit. The control unit is located in the engine compartment and is an electronic switch that, receiving signals from the pulse unit, controls the current in the primary winding of the ignition coil.

The ignition distributor has a centrifugal and vacuum regulator to adjust the ignition timing depending on the engine crankshaft speed and load.

Electronic ignition includes an ignition coil, distributor, control unit, spark plugs, sensors, high and low voltage wires.

The distributor pulse sensor also operates on the Hall effect principle. The electronic control unit receives information from various sensors about engine load, crankshaft speed, etc. and calculates the most effective ignition advance angle. In addition, the unit constantly monitors the operation of the entire system and warns the driver of serious system malfunctions if they occur using a warning lamp.