The purpose of the ignition system is to create a spark that will ignite the fuel-air mixture in the cylinder of an engine. The tip of each spark plug contains a gap that the voltage must jump across in order to reach ground. That is where the spark occurs. The job of the ignition system is to produce that high voltage from a 12 volt source and get it to each cylinder in a specific order, at exactly the right time. The ignition system has two tasks to perform. First, it must create a voltage high enough (20,000+) to arc across the gap of a spark plug, thus creating a spark strong enough to ignite the air/fuel mixture for combustion.
Second, it must control the timing of that the spark so it occurs at the exact right time and send it to the correct cylinder (Bergwall, 1973, pp.9). The ignition system is divided into two sections, the primary circuit and the secondary circuit. The low voltage primary circuit operates at battery voltage (12 to 14.5 volts) and is responsible for generating the signal to fire the spark plug at the exact right time and sending that signal to the ignition coil. The ignition coil is the component that converts the 12 volt signal into the high 20,000+ volt charge. Once the voltage is stepped up, it goes to the secondary circuit which then directs the charge to the correct spark plug at the right time (Schwaner, 1992, pp.5)
The basic principle of the electrical spark ignition system has not changed for over 75 years. Currently, there are three distinct types of ignition systems: The Mechanical Ignition System; this was used prior to 1975. It was mechanical and electrical and used no electronics.
The Electronic Ignition System; started finding its way to production vehicles during the early '70s and became popular when better control and improved reliability became important with the advent of emission controls. The distributor less; it became available in the mid '80s. This system was always computer controlled and contained no moving parts, so reliability was greatly improved. Most of these systems required no maintenance except replacing the spark plugs at intervals from 60,000 to over 100,000 miles (Spazio, 1989, pp.33)
The distributor; is the bravado hub of the ignition of mechanical system and has two responsibilities to serve. First, it is accountable for activating the ignition coil to produce a spark at the accurate time that it is essential. Second, the distributor duty is direct that spark to the appropriate cylinder. The circuit that commands the ignition system is easy as well as straight forward as shown on the above diagram. Ignition switch; when key is inserted in it and turned to the Run position, it sends current from the battery via a wire straight to the positive (+) elevation of the ignition coil. Ignition coil; in the interior of the coil is a chain of windings copper that loop about the coil in excess of a hundred times prior to depart out the negative (-) area of the coil.
Commencing there, a wire seize this current above to the distributor and is linked to a particular on/off switch, called the points; When the points are clogged, this current moves openly to ground. When current streams from the ignition switch, throughout the windings in the coil, then to ground, it creates a tough field of magnetic within the coil. The variable point; traverses on a 4, 6, or 8 lobe cam that is accumulated on a revolving shaft in the distributor. As it turns around, the cam shoves the points open also closed. Each time the points open, the stream of current is broken up via the coil, thus breaking up the magnetic field and discharge an elevated voltage flow in the course of the second coil windings. These voltage surges go out the apex of the coil through the high-tension coil cable. The coil wire; goes straight to the core of the distributor cap. Under the cap is a rotor; which is accumulated on top of the revolving shaft. The rotor has a metal ribbon on the top that is in regular contact with the hub mortal of the distributor cap.
In conclusion, (Kaisha 1980) concluded that ignition system uses a condenser; which is an uncomplicated capacitor that can save a diminutive quantity of current as well as operate like a conduit to ground. By the time the condenser is drenched, the points are moreover extreme apart for the little total of voltage to leap diagonally the ample point gap. While the arcing transverse the breaching points is removed, the points stay longer thus no static on the data lines as of point arcing.