Spark Plugs Electrical Properties

 

The fouling of insulator tip surface with combustion deposits reduces electrical insulation resistance . If the insulation resistance drops, there also occurs a drop in electrical voltage supplied to the spark plug from the ignition system. If, as a result of heavy fouling of the insulator tip, the insulation resistance decreases down to the value when the electrical voltage supplied from the ignition system is lower than the voltage required by the spark plug, there will be misfire of spark between the spark plug electrodes and a failure of the engine function.

Reduction of the insulation resistance from electric energy leakage on the insulator tip surface 

 

• voltage required by the spark plug
• voltage supplied by the ignition system

Voltage required by the spark plug and voltage supplied by the ignition system. In order that a discharge can occur between the spark plug electrodes, it is necessary that the ignition system can supply voltage of a certain value.

If the spark plug requirement concerning the voltage supplied by the ignition system exceeds its possibilities, there will not occur any spark jump across the spark gap. It generally applies that the spark plug voltage requirement increases if the electrode gap rises and during acceleration. The voltage supplied by the ignition system decreases at starting, low ambient temperatures and at a high speed of the engine.

 

Relation between voltage supplied by the ignition system and the spark plug requirement 

A. voltage required by the spark plug (new) 
A1. voltage required by the spark plug (used) 
B. voltage supplied by the ignition system 
C. insufficient voltage supplied by the ignition system

 

 

 

 

Relation between electrode gap and voltage requirement of the spark plug

 

 

Relation between the spark plug wear and spark plug voltage requirement

 

 Electrical  Conductivity comparison between precious metals used in Spark Plug technology. Electrical Conductivity plays a vital role in spark plug performance. The more efficient the conductivity the less strain that is put on your ignition system. This allows for a more potent / strong spark which is crucial for force induction, nitrous, high compression and hard to ignite alternative fuels.

 

 

Thermal  Conductivity comparison between precious metals used in Spark Plug technology. Thermal conductivity is vital to prevent pre-ignition detonation, aka "grenading", an engine and builders worst nightmare. The more efficiently a spark plug is able to dissipate the heat being accumulated, the less likely you are to occur pre-ignition detonation which can cause substantial damage to your high performance and racing engines.