Ignition Systems

On a spark-ignition engine (gasoline engine), the combustion process is initiated by an externally supplied ignition. The ignition is responsible for igniting the compressed air/fuel mixture at the right moment. This is done by producing an electric spark between the electrodes of a spark plug in the combustion chamber. Consistent, reliable ignition under all conditions is essential to ensure fault-free engine operation; a misfire can lead to damage of the catalytic converter, poorer emissions, higher fuel consumption and lower engine performance.

The ignition system has to work in perfect concert with the rest of the engine. The goal is to ignite the fuel/air mixture at exactly the right time so that the expanding gases can do the maximum amount of work. If the ignition system fires at the wrong time, power will fall and gas consumption and emissions can increase. When the fuel/air mixture in the cylinder burns, the temperature rises and the fuel is converted to exhaust gas. This transformation causes the pressure in the cylinder to increase dramatically and forces the piston down.