Thursday, February 7, 2008

Ignition System

An Internal Combustion Engine need an ignition system for igniting the combustible mixture inside each cylinder at the proper moment. In the Diesel Engine, the air inside the cylinder is compressed enough to raise the temperature above the ignition point, so the fuel is ignited as soon as it is injected into the cylinder. This is called compression ignition. The Gasoline Engine, however, required a more complex system, called spark ignition, which uses an electric spark to ignite the mixture. The two basic automotive ignition system are the conventional breaker-point system and the newer, electronic ignition.


The automotive ignition system must deliver 10,000 volts up to 300 times per second in order to keep the engine running. 

Breaker Point Ignition System
The breaker point ignition system consist of the source of energy (the battery), the ignition coil, distributor, ignition switch, spark plug and wiring. The entire electrical system includes the ignition system as a sub-system, but contains, in addition, the Generator (or a related device called an alternator), the voltage regulator, the starter, and electric light, accessories, and gauges.

Electronic Ignition
The electronic ignition system performs the same basic function as the conventional systems but with one major difference; the battery-to-coil circuit is closed and opened electronically in the former rather than mechanically as in the breaker point system. The cam is replaced with a rotator that has metal tips on it. As the rotor turns, the tips pass by a pickup-coil assembly. Each time a tip aligns with the assembly, a magnetic pulse is generated in the coil. These pulses are used to generate the necessary high voltage surge.

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