Types of car ignition coils_Product knowledge

1. Closed Magnetic Circuit Ignition Coils In recent years, closed magnetic circuit ignition coils with high energy conversion efficiency have been used in electronic ignition systems of automobiles. Compared with the traditional ignition coil, its iron core is in the shape of a 'mouth' or 'saying' with a small air gap.
The magnetic flux generated by the primary winding in the iron core forms a closed magnetic circuit through the iron core, which reduces the leakage loss, so the conversion efficiency is high, up to 75%. In addition, the closed magnetic circuit ignition coil also has the advantages of small size, light weight, and little interference to the radio.
2. Open magnetic circuit ignition coil
Open magnetic circuit ignition coil adopts cylindrical iron core. The magnetic flux generated by the primary winding in the iron core forms a magnetic circuit through the magnetic conductive steel sleeve, and the upper and lower parts of the iron core The magnetic field lines passing through the air, the magnetic resistance of the magnetic circuit is large, the leakage of magnetic flux is large, and the conversion efficiency is low, generally only about 60%. According to the number of low-voltage terminals, there are two types of terminals: two-terminal type and three-terminal type.
The three-terminal ignition coil is equipped with additional resistance, and its low-voltage terminals are marked with '-There is no additional resistance in the two-terminal ignition coil, only two terminals marked with '+' and '-'. Whether it is a three-terminal or two-terminal open magnetic circuit ignition coil, the internal structure is the same. The secondary winding is wound with 11 000 to 23 000 turns of enameled wire with a diameter of 0.06 to 0.10 mm on the insulating paper tube; the primary winding is wound with 240 to 370 turns of enameled wire of 0.5 to 1.0 mm.
3. Dual-cylinder ignition coil
The simultaneous ignition of the electronically controlled dual-cylinder engine means that two cylinders share one ignition coil, that is, one ignition coil has two high-voltage output ends, which are respectively connected to the spark plug and are responsible for 2 Cylinders fire simultaneously. This ignition method requires that the working strokes of the two cylinders ignited at the same time differ by a crank angle of 360°, that is, when one cylinder is at the top dead center of the compression stroke, the other cylinder is at the top dead center of the exhaust stroke. The electronically controlled twin-cylinder simultaneous ignition system can only be applied to an engine with an even number of cylinders.
4. Independent ignition coil
Each cylinder is equipped with one independent ignition coil, which has the advantage of small energy loss, reduced heat generation, and improved service life.
A two-wire independent ignition coil, one wire is the positive pole of the power supply, and the other is the negative pole of the primary coil. The on-off of the negative pole is controlled by the triode of the ecu, so that the secondary coil induces a high voltage, and one end of the secondary coil is connected to The other end of the spark plug is connected to the positive pole of the power supply, that is to say, it shares the positive pole with the primary coil. When the primary coil is disconnected, the secondary coil forms a loop through the positive pole of the power supply - ground - spark plug - secondary coil.