The basic principles of the electric spark ignition system have not changed in nearly a century, but the method by which the spark is created and distributed has greatly improved with advances in technology.
There are three basic types of automotive ignition systems: distributor-based, distributor-less, and coil-on-plug (COP). Early ignition systems used fully mechanical distributors to deliver the spark at the right time. Next came more reliable distributors equipped with solid-state switches and ignition control modules. These were known as distributor-based ignition systems. Then, even more reliable fully electronic ignition systems without distributors were created. These are known as distributor-less ignition systems. Finally, the most reliable electronic ignition systems to date were created. These modern systems are known as coil-on-plug (COP). Coil-on-plug fully electronic ignition systems are computer controlled. In addition to improving the accuracy of spark timing, the COP ignition systems use redesigned ignition coils capable of creating higher voltages and a hotter spark which improve the way the engine performs.
Have you ever wondered what happens when you put your key in your vehicle’s ignition, turn the key, and your engine starts and continues running? Today, I’m going to tell you. For the ignition system to operate properly, it must be capable of doing two jobs at the same time. The first job is to increase the voltage from the 12.4 volts provided by the battery to the more than 20,000 volts necessary to ignite the compressed air and fuel mixture in the combustion chamber. The second job of the ignition system is to ensure the voltage is delivered to the correct cylinder at exactly the right time. In order to do this, a mixture of air and fuel is first compressed by a piston in the combustion chamber. This mixture must then be ignited. This task is performed by the engine’s ignition system that includes components such as the battery, ignition key, ignition coil, triggering switch, spark plugs, and engine control module (ECM). The ECM controls the ignition system and distributes the electrical power to each individual cylinder. The ignition system must provide sufficient spark at the right cylinder at the precise time and do it frequently. The slightest error in timing will cause engine performance issues.
Automotive ignition systems have to generate a spark strong enough to jump across a spark plug gap. In order to do this, ignition systems use an ignition coil. The ignition coil acts as an electrical power transformer.
The ignition coil transforms the battery’s low voltage into the thousands of volts needed to create an electric spark in the spark plugs to ignite the air and fuel mixture. In order for the necessary spark to occur, the voltage to the spark plug must average between 20,000 and 50,000 volts. The ignition coil is made with two windings of copper wire wrapped around an iron core. These are known as the primary winding and the secondary winding. The goal of the ignition coil is to create an electromagnet by running battery voltage through the primary winding. When the vehicle’s ignition system triggering switch turns off the power to the ignition coil, the magnetic field collapses. As it does, the secondary winding captures the collapsing magnetic field from the primary winding and delivers this voltage to the spark plug, thus starting your vehicle’s engine.
Worn spark plugs and faulty ignition components will decrease the performance of your engine and can create a wide range of engine running problems including misfiring, lack of power, poor fuel economy, difficult starting, and possibly a check engine light. These problems can damage other critical vehicle components.
In order to keep your vehicle running smoothly and safely, regular maintenance of your ignition system is essential. A visual inspection of your vehicle’s ignition system components should be performed at least annually. All of the components of your ignition system should be inspected regularly and replaced when they begin to show signs of wear or failure. Also, be sure to inspect and replace your spark plugs at the interval recommended by your vehicle’s manufacturer. Do not wait until a problem arises to care for your vehicle. Regular maintenance is key to the life and quality of your vehicle’s engine.