Ignition coil classification
The classification of the ignition coil is the basic component that converts the low-voltage electricity of the power supply into high-voltage electricity. Commonly used ignition coils are divided into two types: open magnetic ignition coil and closed magnetic ignition coil.
(1) Open magnetic circuit ignition coil
The open circuit ignition coil is made using the principle of electromagnetic mutual inductance. The structure is mainly composed of a primary coil and a secondary coil on a core of a silicon steel sheet, an outer resistance of the casing and the like. The open circuit ignition coil has two terminals and three terminals.
(2) Closed magnetic circuit ignition coil
The closed magnetic circuit ignition coil winds both the primary winding and the secondary winding on a square or a zigzag core. The magnetic flux generated by the primary winding in the iron core constitutes a closed magnetic circuit through the iron core.
The advantage of the closed magnetic circuit ignition coil is that the magnetic leakage is small, the magnetic resistance of the magnetic circuit is small, and the energy loss is small, and the energy conversion rate is high, up to 75% (only 60% of the open magnetic ignition coil). The closed magnetic ignition coil adopts thermosetting resin as the insulating filler, and the outer casing is injection molded by hot melt plastic, and its insulation and sealing performance are superior to the open magnetic ignition coil. The small size can be directly mounted on the distributor cover, which not only has a compact structure, but also eliminates the high-voltage wire between the ignition coil and the distributor, and can reduce the secondary capacitance, so it has been widely used in the electronic ignition system.