How Do Automotive Electronic Ignition Systems Work?

An electronic ignition system works by using sensors, transistors and electrical switches to deliver high voltage to the engine's spark plugs. This helps the engine generate a stronger spark, which leads to improved combustion and emissions control.

Compared to traditional ignition systems, an electronic ignition system does not need a resistor to reduce the operating voltage of the primary circuit to prolong the life of points. This means that the ignition system is operating on full battery voltage, and thus a stronger spark is possible.

Major components of an electronic ignition system include the ignition coil, ignition wires, ignition control module, camshaft sensor, crankshaft position sensor and the spark plugs. The crankshaft position sensor informs the engine computer how fast the engine is running. Likewise, the camshaft sensor tells the computer when to activate the fuel injectors and deliver fuel. The computer both accepts information and informs the ignition control module what to do based on the information it has received.

In turn, the ignition control module collapses a magnetic field built up inside each one of its ignition coils. The coils produce a high voltage as a result of this magnetic field collapse, which travels through the ignition wires and to the spark plugs. In general, an electronic ignition system is capable of sending around 50,000 volts to the spark plugs to ignite the fuel and air mixture.

Electronic ignition systems have been the standard since the 1970s, as mechanical ignition systems were phased out around the same time. A car that has been built from late 1970s onward is likely equipped with an electronic ignition system.