Ignition system (petrol engines) — description (Peugeot 406)

On all models, the ignition system is combined with the fuel injection system and represents a unified engine management system from a single ECU unit.

On 1.6 liter engines, the ignition system consists of 2 ignition coils. Each ignition coil actually consists of 2 separate high-voltage windings that supply a spark to two cylinders each (one to cylinders #1 and 4, and the other to cylinders #2 and 3). The ignition pulse is supplied to two spark plugs at once for each engine cycle, one on the compression stroke, one on the exhaust stroke (the ignition spark on the exhaust stroke has no effect on the engine's operation and is therefore wasted). The ECU uses inputs from various sensors to calculate the required spark advance setting and the energy storage time in the ignition coil.

On 1.8 and 2.0 liter engines, the ignition system consists of 2 amplifier modules and 4 ignition coils. Each ignition amplifier module controls two ignition coils, combined with spark plug tips and mounted directly on the spark plugs, one coil per spark plug. This eliminates the use of high-voltage wires. The ECU uses inputs from various sensors to calculate the required ignition timing and the energy accumulation time in the ignition coil.