Ignition coil type
The ignition coil is divided into two types according to the magnetic circuit: open magnetic type and closed magnetic type.
Open magnetic circuit ignition coil
The open-circuit magnetic circuit ignition coil is usually a can-shaped structure. It consists of several silicon steel sheets to form a rod-shaped iron core, and the secondary coil and primary coil are respectively wound on the outside of the iron core. The wire diameter of the secondary coil is 0. 05~1mm enameled wire, with turns of 20000~30000. The wire diameter of the primary coil is 0. 5～1。 0mm, thicker than the secondary coil, and the number of turns is only 150~300. The primary coil is wound on the outside of the secondary coil, so the magnetic flux change generated by the secondary coil is exactly the same as that of the primary coil. The winding direction of primary coil and secondary coil is the same. The starting end of the secondary coil is connected to the high-voltage output connector, one end of which is connected to the starting end of the primary coil and the "+" terminal of the housing. One end of the primary coil is connected to the "I" terminal of the housing and to the collector of the power transistor in the igniter. The igniter controls the opening and closing of its primary coil current.
Closed magnetic circuit ignition coil
The magnetic core of the closed magnetic circuit ignition coil is closed. The magnetic flux passes through the magnetic core, and the permeability of the magnetic core is about 10000 times that of air. Therefore, if the open magnetic circuit ignition coil wants to obtain the same magnetic flux as the closed magnetic circuit ignition coil, its primary coil must have a large magnetomotive force (ampere turns). Therefore, the primary coil with more turns and larger wire diameter must be used; The number of turns of the primary coil is large. If you want to obtain the same turn ratio, you need to increase the number of turns of the secondary coil. Therefore, it is impossible to miniaturize the open-circuit ignition coil. On the contrary, the closed magnetic circuit ignition coil can effectively reduce the magnetomotive force of the coil and miniaturize the ignition coil due to its small magnetic resistance. At present, the closed magnetic circuit ignition coil has been quite miniaturized and can be integrated with the igniter and even the spark plug. The combustible compressed gas in the cylinder is ignited by the spark plug. The traditional ignition coil is open-magnetic. Its iron core is made of 0.3mm silicon steel sheet, and the iron core is wrapped with secondary coil and primary coil. For the closed magnetic type, the primary coil is wound with an iron core similar to III, and the secondary coil is wound externally. The magnetic line of force is composed of iron core, forming a closed magnetic circuit. The advantages of closed field ignition coil are less magnetic leakage, small energy loss and small volume. Therefore, the closed field ignition coil has been widely used in the electronic ignition system.
