The Spark Plug
Spark plugs are nothing more than two wires close together so that a spark can jump between them. One wire is encased in ceramic to insulate it from the other; the second wire, which is connected to a ground. The function of the spark plug is to introduce the ignition energy into the engine’s combustion chamber and to initiate combustion of the compressed air-fuel mixture. It accomplishes this task by generating a spark between its electrodes, which then generates the required heat to ignite a smooth burn of the air/fuel mixture.
The spark plug is an important factor in determining optimal performance and reliable functioning of an engine. It plays a major role in fuel economy, in achieving a clean and efficient combustion, and the reliable operation of engines and catalytic converters. When they are worn out, your engine will misfire, be difficult to start, waste gasoline and degrade the performance which was designed into it.
During operation, the spark plug is subjected to both wear and to fouling and should be replaced at regular intervals. In the course of its service life, the spark plug undergoes changes that increase the required ignition voltage. When the required voltage reaches a level that can no longer be compensated for by the voltage reserve, the result is misfiring. These changes can be caused by:
- Electrode wear
- Engine wear
- Abnormal operating conditions (pre-ignition, detonation, high oil consumption)
It is therefore very important to regularly check the condition of the spark plugs. As part of normal maintenance, spark plugs should be checked, removed, cleaned, re-gapped and re-installed every 5000 to 6000 miles to maintain proper performance. This interval varies according to your driving habits and type of car.