Gasoline-fueled piston engines require an ignition source to set off the explosion that converts the chemical potential energy of the air-fuel mixture into thermal energy which the engine can convert into mechanical energy. Each type of ignition source has advantages and disadvantages (which we’ll get to soon), but all have the same basic objective, which is to efficiently set off a quick explosion that burns all the fuel in the cylinder. There are four ignition systems commonly used in 4-stroke, 2-stroke, and rotary engines, along with an oddball only used in small 2-strokes.
Secondary Ignition: The Art Of Spark by Scott Weaver This article describes the components of a conventional distributor ignition system, and how they produce a spark. Scott also shows what a (secondary coil) ignition waveform looks like, and describes its different parts. Read Article at Tomorrow’s Technician Maintaining Engine Spark by Mac Vandenbrink An explanation …
The short answer is that it’s our modern take on an old type of tool. The long answer is… longer.
One of the questions we hear most often is ‘what is a wasted spark?’. Wasted sparks are also known by many other names, including ‘waste sparks’, ‘exhaust sparks’, which adds to the confusion.