Spark plugs with auxiliary gauge: for engines that generate much charcoal
Developed for engines and modes of driving that they generate much charcoal, with auxiliary gauge spark plugs have a box next to the insulator. Thus, if the tip of the insulator is tiznada and starting the engine, the ignition voltage flows up to the height box.
Since the jump to box represents one less than the output resistance through the insulator, produced a spark to the box jump lighting so the air / fuel mixture.
Spark plug reaches the self-cleaning, 450 ° C temperature, soot deposits are burned and the spark can be channelled through the ground electrode.