Ignition question
#2
10-12-2008 | 04:28 AM
Member
Joined: Jan 2005
Posts: 25
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From: GARDEN GROVE, CA
The ignition coil creates the high voltage for the plug, in a three part process. The first part occurs during dwell, where the primary of the coil stores energy, in the form of a magnetic field. At spark time, the magnetic field is allowed to collapse, creating a 400v pulse at the coil negative. The coil is also a step up transformer, so the 400v pulse is converted into a 40,000v pulse to fire the plug.
The 40,000 and 60,000 volt claims by coil manufacturers are meaningless, since they are measured with no spark plug. Connect a plug in free air, and all you will see is about 2000v, since that's all it takes to jump the gap. Cylinder pressure and condition of the electrodes requires a higher voltage to jump the gap. If it only takes 20,000 v to fire the plug under load, that's all you'll measure.
The 40,000 and 60,000 volt claims by coil manufacturers are meaningless, since they are measured with no spark plug. Connect a plug in free air, and all you will see is about 2000v, since that's all it takes to jump the gap. Cylinder pressure and condition of the electrodes requires a higher voltage to jump the gap. If it only takes 20,000 v to fire the plug under load, that's all you'll measure.
