Ignition System

In the case of gasoline-fueled, spark-ignition engines, the ignition system creates the high-voltage spark necessary to ignite the combustible mixture in the cylinders. An ignition distributor, synchronized to the rotating parts of the engine, delivers the spark to the right cylinder at precisely the right time. Since each cylinder has to have a spark once for every two revolutions of the crankshaft, the distributor always turns at one-half crankshaft speed. The basic system is shown schematically in Fig. 1-5. For more information, see IGNITION.

Fig. 1-5.

Schematic representation of basic spark-ignition system. Ignition coil boosts voltage, electronic control unit and distributor control timing, and distributor delivers spark to spark plugs.