Ignition coil
An
ignition coil (also called a
spark coil) is an
induction coil in a
automobile's
ignition system which
transforms a
storage battery's 12
volts to the thousands of volts needed to spark the
spark plugs.
This specific form of the
autotransformer, together with the
contact breaker, converts low voltage from a battery into the
high voltage required by spark plugs in an
internal combustion engine.
In modern ignition systems, the ignition distributor is omitted and ignition is instead electronically controlled. Firing voltage is achieved either by using individual coils placed on top of the spark plug
(coil-on-plug or
Direct Ignition), or through a "waste spark" system, in which two spark plugs share the same coil, causing both to fire simultaneously - the fuel in the cylinder that is nearing the end of its compression stroke is ignited, whereas the spark in its companion that is nearing the end of its exhaust stroke has no effect. The waste spark system is more reliable than a single coil system with a distributor, and cheaper than coil-on-plug.
The disruptive discharge
Tesla coil is an early predecessor of the "ignition coil" in the ignition system. Tesla also gained ,
"Electrical Igniter for Gas Engines", on August 16, 1898. It used the principles of the ignition coil used today in automobiles.
A. Atwater Kent, in 1921, patented the modern form of the ignition coil.
* An
Oudin coil is a
disruptive discharge coil.
* -
Induction coil structure - Arthur Atwater Kent - 1921
* -
Induction coil - Arthur Atwater Kent - 1923
* -
Induction coil - Arthur Atwater Kent - 1923
* -
Ignition coil - Arthur Atwater Kent - 1926
* -
Ignition system -
Ernst Alexanderson - 1929
*
Ignition Coil Driver circuit
