Traditional Ignition System

- May 05, 2019-

Traditional ignition system

The power source is a battery, and its voltage is 12V or 24V. The ignition coil and the breaker are combined to generate a high voltage of 10000V or more. Divided into primary and secondary circuits. The ignition coil is actually a transformer consisting mainly of a primary winding, a secondary winding and an iron core. The breaker is a cam operated switch. The breaker cam is driven by the engine valve cam and rotates at the same speed, that is, the crankshaft gear rotates two times per revolution, and the camshaft rotates one turn. In order to ensure that the crankshaft rotates twice in each cylinder, the number of flanges of the breaker cam Generally equal to the number of cylinders of the engine, the contacts of the breaker are connected in series with the primary winding of the ignition coil to cut or switch the circuit of the primary winding.

When the contact is closed, the primary circuit is energized, and the primary current flows from the positive pole of the battery through the ignition switch, the primary winding of the ignition coil, the contact arm of the breaker, the contact, and the ground current flows back to the negative pole of the battery, which is a low voltage circuit. When the contact is opened, a magnetic field is generated around the primary winding when it is energized, and is strengthened by the action of the iron core. When the breaker cam opens the contact, the primary circuit is cut off, the primary circuit drops rapidly to zero, and the magnetic flux in the core is rapidly attenuated and disappears, thus being induced in the secondary winding of the wire with a large number of turns. The high voltage causes the gap between the two poles of the spark plug to be broken down, creating a spark.

The higher the current drop in the primary winding, the greater the change in flux in the core and the higher the induced voltage in the secondary winding. The primary circuit is a low voltage circuit and the secondary circuit is a high voltage circuit.

At the moment when the breaker contacts are separated, the sub-pole circuit is just aligned with the side electrode, and the secondary current flows from the secondary winding of the ignition coil, through the battery positive electrode, the battery, the grounding electrode, the spark plug side electrode, the spark plug center electrode, and the high voltage. The wire and the distributor flow back to the secondary winding.