Static (without distributor) ignition system (DIS)
Although the ignition system is referred to as a static ignition system, its basic functions are the same as on models equipped with a conventional non-contact ignition system. In static (without distributor) ignition system (DIS) or the so-called «idle spark system» two ignition coils are used to create a spark discharge on two spark plugs at the same time. One cylinder creates a spark discharge on the compression stroke, and a paired cylinder - on the exhaust stroke, where the spark does not perform any useful function, i.e. is «idle».
Therefore, two pairs of ignition coils are required for a 4-cylinder engine. Approximately 3 kV is still needed to create «idle spark». Each ignition coil receives voltage from the ignition switch. In addition, separate connectors for each ignition coil are made between the electronic control unit and the amplifier. In fact, the electronic control unit and amplifier consists of two separate circuits, so that each ignition coil can be turned on individually and in turn.
Direct ignition (DI)
Unlike a static ignition system that sparks two spark plugs at the same time, some models use two amplifiers and four ignition coils to spark each spark plug in cylinder order as the piston approaches TDC on the compression stroke.
This is the sequence: signals from the crankshaft angle sensor (CAS) come to the electronic control unit when the piston of cylinder No. 1 or No. 4 is set to the TDC position, and also to identify the piston of cylinder No. 1, the crankshaft angle sensor sends a signal to the electronic control unit. Having received these signals, the electronic control unit activates the corresponding amplifier and thus the corresponding ignition coil gives a spark at the right time.