Current ignition system design:

Since engine performance relies heavily on accurate ignition timing:

Engineers look carefully at how to eliminate more moving parts from the ignition system

This led to the elimination of the distributor in a design named:

Distributorless Ignition System(DIS)

Why do DIS Systems use on ignition coil to operate two spark plugs?

So a V8 engine would require four separate coils instead of one

The increase in the number of coils allows:

Each coil more time to build up its electric charge and, therefore, deliver a more powerful spark when the time comes to discharge

However, this system still utilizes spark plug wires, which:

Degrade time and eventually need replacement for the DIS system to function properly

The most recent ignition system designs:

Have eliminated spark plug wires together

These systems are known as:

Coil on plug ignitions

Individual ignition coils are mounted directly:

Onto spark plugs

The distribution of the coils is controlled by:

The vehicle computer system

While the incorporation of computer control has increased control of spark timing:

The elimination of moving and high maintenance components has led to very accurate control of spark timing, which is critical for optimum engine efficiency and emissions, as well as increased reliability of ignition systems