In order for the petrol engine to operate correctly and efficiently, the spark must be ignited with absolute reliability. Misfiring, for example, could result in an entire cylinder filling with the air-fuel mixture, reaching the exhaust system unburned and then only combusting once within the catalytic converter. Just a few misfires may be enough to damage the catalytic converter or even render it entirely useless.
Igniting at the right time
The spark must also ignite at exactly the right time. The ideal time is just before the piston has reached its highest point and the compression is at it greatest. An ignition which is too early or late has a negative impact on engine efficiency and leads to increased fuel consumption and an increase in exhaust emissions.
Explosion through local heating
The ignition spark does not directly ignite the fuel-air mixture in the combustion chamber. Its path through the gas mixture causes intense local heating, which ultimately leads to the explosion of the mixture. With the construction of a spark plug it is important to ensure that this valuable heat does not escape too quickly. At the same time the spark plug also plays an important role in conducting the heat to the cylinder head in order to keep the operating conditions under control.
Increasingly demanding requirements on spark plugs
The conditions in which spark plugs must operate have become increasingly more difficult and demanding over the past ten years. In addition, expectations in regard to the service life of a spark plug have become significantly higher. In order to overcome these difficulties and fulfil the increased expectations, NGK invests in research, technology and development. The results are new materials and production techniques which make the spark plugs more capable and longer-lasting than ever before.