In modern ignition systems each spark plug has its individual coil, sitting right on top of it, in a so called Direct Ignition (DI) module.
Early history[]
The disruptive discharge Tesla coil [1] is an early predecessor of the "ignition coil" in the ignition system. Tesla also gained U.S. patent 609250, "Electrical Igniter for Gas Engines", on August 16, 1898. It used the principles of the ignition coil used today in automobiles. A. Atwater Kent [2], in 1921, patented the modern form of the ignition coil.