Secondary Ignition System - Get an online auto repair estimate
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The ignition system is divided in to two sections, the primary ignition system and the secondary ignition system. The secondary ignition system originates inside the ignition coil with the secondary coil windings. The secondary ignition system creates and delivers the high voltage needed to bridge the spark plug gap and ignite the compressed air to fuel mixture inside the individual cylinders. This high voltage is created inside the secondary windings of the ignition coil. The purpose of the spark is to mimic a small, tightly controlled, flame source that initializes a predictable flame front that burns across the top of the piston, thereby creating a rapidly expanding gas that pushes down on the top of the piston.
The ignition coil secondary windings absorb and transform the electrical energy that has been stored or 'waiting' inside the ignition coil primary windings. When the electricity 'jumps' from the primary windings it is transformed from a 12-volt system voltage to a very high voltage spark that can be as high as 80,000 volts direct current (DC). This high voltage, high pressure (voltage is electrical pressure) condition is urgently seeking a path to ground so it travels out of the ignition coil high voltage, secondary terminal that looks somewhat like the connectors on top of the large transformers inside power stations.
On distributed ignition systems a separate ignition coil wire connects the output of the ignition coil to the coil terminal of the distributor. The distributor is a component that distributes the coil spark to each individual cylinder by turning device called an ignition rotor in the distributor cap. The distributor cap, sometimes referred to as the ignition cap, is usually a round device that looks somewhat like a hat or 'cap'. The cap has a center coil terminal surrounded by individual cylinder terminals that connect to each spark plug by way of dedicated spark plug wires.
The ignition rotor is mounted on a rotating shaft inside the distributor and usually connects to the camshaft via a gear mechanism. As the camshaft rotates it turns the ignition rotor whose center touches the coil terminal. The rotating outer end of the ignition rotor passes very closely by each individual distributor cylinder terminal in the engine's firing order. When the rotor is pointing its outer end to an individual cylinder, the coil is 'fired' by the ignition module. This sends a high voltage spark out of the distributor and in to the spark plug wire that ultimately 'fires' the spark plug.
There is an individual spark plug wire for each cylinder. This is a high tension, and high voltage capable, rubber insulated cable that has a carbon core embedded in nylon. It is not like a typical electrical wire or cable that has a copper core. The carbon core can withstand the constant firing of the high voltage needed to energize the spark plugs without overheating or melting.