A spark ignition system is a critical component in many engines, primarily responsible for initiating the combustion process that generates power. Its function is to create a precisely timed electrical spark inside the engine's cylinders.
The Core Ignition Process
The fundamental operation of a spark ignition system involves generating a very high voltage and delivering it to the spark plug. This high voltage is necessary to overcome the resistance of the air gap at the tip of the spark plug.
Generating and Delivering the Spark
The system, which includes components like an ignition coil, distributor (in older systems) or ignition modules, and high-tension (HT) leads, builds up electrical voltage to an extremely high level. This voltage is then sent to the spark plug in each cylinder at the correct moment in the engine cycle.
According to the provided information: "When the ignition system sends a voltage down the HT lead to the spark plug, the high voltage causes a spark to jump between the spark plug centre electrode and the earth electrode(s)." This moment is when the electrical energy bridges the gap, creating a visible, hot spark.
Igniting the Fuel Mixture
The purpose of this spark is to ignite the compressed mixture of fuel and air that has been drawn into the engine cylinder. This mixture is highly combustible, and the intense heat from the spark provides the energy needed to start the reaction.
As the reference further explains: "The spark ignites the explosive air/fuel mixture, which expands, pushing the piston down the cylinder." This rapid expansion of burning gases creates the force that drives the piston downwards, performing work and powering the engine.
In summary, a spark ignition system works by generating high voltage to create a spark at the spark plug, which in turn ignites the fuel-air mixture in the cylinder, leading to combustion and engine power.
