Ignition System theory

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Old 08-25-20, 02:33 PM
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Ignition System theory

I was studying an article on how a 12 volt battery can generate more voltage than 12 volts to fire a spark plug in an engine. The name Michael Faraday came up. (inventor of the electric motor 1861) He figured out that adding a power source to two coils of wire (like an ignition coil in a car) adding a switching mechanism (breaker points) and a capacitor vis a vis a condenser to absorb the collapse of the magnetic field charge. Do any of you know how anyone figured out how many coils of wire were needed to generate the power needed to fire a spark plug?
 
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Old 08-25-20, 03:48 PM
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Many of the famous scientists/inventors had staff performing countless experiments. I think sometimes working with a hypothesis and other times they just did stuff to see what would happen (I picture a underpaid lab assistant asking a coworker to lick the blue spark to see what would happen. The predecessor to "hold my beer".) At that point some of electromagnetism's magic had already been discovered so they just kept taking baby steps further and further in their experimentation. One thing that comes to mind is the filament for light bulbs. It was known for a long time that passing enough current through something could make it glow but it took hundreds or thousands of experiments to find the magic combination of a tungsten alloy filament in an inert gas to create what became the light bulb.
 
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Old 08-25-20, 08:06 PM
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I'm sure the exact turns amount was experimental.

I don't think they even invented the spark coil at first. The first experiments were applying a voltage to a single coil of wire and receiving an EMF jolt when it was disconnected. Further experimenting yielded multi coil units.
 
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Old 08-26-20, 04:52 AM
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As Edison said about trial and error vis-a-vis his light bulb: I have not failed. Ive just found 10,000 ways that wont work.
 
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Old 08-26-20, 05:01 AM
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An ignition coil is a step up transformer with the output voltage being a function of the primary/secondary turns ratio and the primary coil voltage. The primary coil voltage is a function of the primary coils inductance (related to the number of turns) and the rate of change of the primary current. So the faster the primary current changes, the less number of turns needed to generate the same output voltage.
 
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Old 08-26-20, 06:58 PM
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No arguments with any of the above statements. It would just be cool to know who, when and where, somebody put all this induction and transformer stuff into a design for an internal combustion engine spark voltage, which is a lot more than 12 volts.
 
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Old 08-27-20, 05:45 AM
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The first ignition systems were magneto based. Suggest you start there.
https://en.wikipedia.org/wiki/Ignition_magneto
 
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Old 08-27-20, 06:44 AM
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Magneto Based ignition

THISOLDMAN that Wikipedia article was GREAT! I have a tractor with a Kohler k241 S that is set up like the combination system described in the article. It has a battery, points and condenser, a coil like a car, and a Magneto system under the flywheel. Always wondered why they did that! (gives the battery back just enough juice to keep it charged up)

Thanks

WML13



















 
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Old 08-27-20, 08:00 AM
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I learned early on when holding an aircraft magneto you have to be careful if you turn the shaft. You hear the snap of the impulse coupling a second after the shock hits you.
 
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