5. Ignition System
The Ignition System of a Engine is a important part in the work of the engine. without the ignition system the engine cannot work. There will be no ignition. Ignition system consists of several parts which make a complete workout. Those parts are
- Switch
- Battery
- Ignition Coil
- Spark Plug
- Contact Breaker
5.1 Parts
5.1.1 Switch
This acts in turning on and off the whole ignition system. Without a switch in place, a Ignition system cannot be controlled as per expectations.
5.1.2 Battery
The battery powers the ignition system for a cold start. The battery provides the base voltage of 12V which is later converted to high voltages and used in igniting fuel.
5.1.3 Ignition Coil
The ignition coil converts the power from battery to high voltage. The ignition coil consists of two coils namely, Primary Coil and Secondary Coil. The converted voltage ranges from 20,000V to 40,000V.
5.1.4 Spark Plug
The spark plug fires the fuel inside the combustion chamber. The spark gap is set to be 0.8mm to 1.8mm depending on the produced voltage. The electrode openings are made of Nickel to sustain high temperatures and provide a resistant to preheat the fuel.
5.1.5 Contact Breaker
A Contact breaker is placed in between the distributor and the secondary coil to terminate the power according to a timing. without a contact breaker in place, the secondary coil will not produce any power.
5.2 Operation
A switch is placed in action to stop and start the engine when required. Whenever the switch is turned on, it makes magnetic flux in the Primary Coil of the Ignition Coil. It also creates magnetic flux in the secondary coil where as the wheel fixed on the circuit breaker makes a connection. The connection is breaked when the piston reaches TDC during a compression stroke. Thus making the fuel ignite through the spark on the Spark Plug’s ends. The operation of the Ignition Coil is similar to the transformer.
5.3 Ignition Timing
5.3.1 Centrifugal Advance Mechanism
This mechanism involves use of Mechanical components to function. The distributor is powered by the power of the engine and the distributer contains two discs attached to each other. One disc is carved for allowing space of a movable part attached to the other disc. The flyweight attached in the other disc forces the second disc to move ahead of the cycle while both discs are spinning at a high speed. Thus reducing the time taken to fire the sequence.
The advancement of the second disc varies according to the speed of the engine.
5.3.2 Vacuum Advance Mechanism
This mechanism works on the principle of Engine load. When the engine receives a heavy load, the timing shortens accordingly. It produces a high fuel efficiency rate and increases engine life. The advancement in the vacuum advance mechanisms allow greater savings.
5.3.3 Computer-controlled Ignition
Newer engines typically use computerized ignition systems. The computer has a timing map (lookup table) with spark advance values for all combinations of engine speed and engine load. The computer will send a signal to the ignition coil at the indicated time in the timing map in order to fire the spark plug. Most computers from original equipment manufacturers (OEM) cannot be modified so changing the timing advance curve is not possible. Overall timing changes are still possible, depending on the engine design. Aftermarket engine control units allow the tuner to make changes to the timing map. This allows the timing to be advanced or retarded based on various engine applications.
#Transmission System