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What is good ignitability?
"Ignition performance" refers to an engine's ability to successfully and effectively, burn a wide range of air/fuel mixtures. A good spark plug can improve "Ignition performance"

There are four stages from the time the spark is generated at the gap,
to the combustion of the air/fuel mixture.
1st Stage Spark generation photo
2nd Stage Flame core established photo
3rd Stage Growth of the flame core photo
4th Stage Combustion of air/fuel mixture photo
The quenching action is where the cooler center and ground electrodes drain the energy of the flame core by way of heat transfer. If quenching is severe, the flame core can be extinguished, causing ignition to fail. Therefore, spark plugs designed to reduce the quenching effect have better "Ignition performance".
NGK offers the following types of spark plugs to improve ignitability.
  • V-Groove Spark Plugs
    The center electrode has a 90° V-groove (Refer Q9)
  • Iridium IX Spark Plugs
    Incorporate fine center electrodes. (Refer Q10)
  • Wide Gap Spark Plugs
    The wider gap reduces quenching action. (Refer Q13)
  • Projected Firing End Spark Plugs
    The spark position is closer to the center of the combustion chamber. (Refer Q13)
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