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jerromyjon
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- Automotive gasoline engine ignition voltage polarity inversion
I've recently had a discussion with fellow technicians in the automotive industry about spark plugs and some systems having "opposite polarity" on the ignition coils. (specifically the secondary coil which sends the high voltage pulse to the plug which sparks the fuel)
Common sense tells me that since the base of the plug which contains the electrode is grounded through the engine to the negative terminal of the battery, the high voltage that comes from the coil to the tip of the plug down through the insulator to the other electrode has to be positive polarity.
The evidence they claim is that the "arm" (ground electrode) will wear on one plug and the "center" (spark electrode) will wear on the other, in such systems that use a reversed polarity spark. Also some referred to the "waste spark" coils which have 2 terminals for cylinders which spark on opposite cycles, claiming they also spark in opposite polarity, but they all use the same typical plugs which all ground though the base.
Can anyone make any sense of this?
Common sense tells me that since the base of the plug which contains the electrode is grounded through the engine to the negative terminal of the battery, the high voltage that comes from the coil to the tip of the plug down through the insulator to the other electrode has to be positive polarity.
The evidence they claim is that the "arm" (ground electrode) will wear on one plug and the "center" (spark electrode) will wear on the other, in such systems that use a reversed polarity spark. Also some referred to the "waste spark" coils which have 2 terminals for cylinders which spark on opposite cycles, claiming they also spark in opposite polarity, but they all use the same typical plugs which all ground though the base.
Can anyone make any sense of this?
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