linsheng said that the function of the ignition system is to compress the mixture of air and fuel in the combustion chamber of the engine. It largely determines engine reliability, fuel economy and emissions.
linsheng analytical ignition system consists of five parts: current interruption, high voltage generation, ignition timing control, power distribution and spark plug.
High voltage generating part
It uses the circuit transition process caused by the current interrupted part, and uses the battery and the generator or the magnetoelectric as the low-voltage power source to convert the energy stored in the primary winding of the ignition coil into a high-voltage electric device with a secondary winding output of 15 to 35 kV. The current interrupted part can be divided into contact type and non-contact type. The contact type consists of a breaker circuit that turns the ignition coil on and off. The contactless type consists of a Darlington tube that turns the ignition coil on and off the primary current loop. The former has to maintain the breaker in the process of use, while the latter has high reliability and is now widely used.
Ignition control section
According to the parameters such as the starting speed and the crankshaft position, the intake pipe vacuum degree and the cooling water temperature, the time at which the spark plug is fired (ignition timing) is automatically set at the optimum time. According to the structural characteristics, it can be divided into two types: mechanical ignition advance mode and electronic ignition advance mode. The former consists of a centrifugal advance mechanism and a vacuum advance mechanism installed in the distributor. The latter consists of a sensor and an electronic control module that converts the crankshaft speed and position, intake manifold vacuum, and cooling water temperature into electrical signals and delivers them to the electronic control module. The electronic control module consists of an ignition sequence group and an ignition control group. The ignition sequence group calculates the ignition timing, and the ignition control group controls the conduction of the transistor according to the calculated ignition timing to adjust the ignition advance angle.
Power distribution section
It is a device that connects the high voltage output from the ignition coil to the spark plug of the corresponding cylinder as little as possible in the order of ignition.
The current distribution methods are mechanical and electronic. The mechanical distribution method is done using a distributor. Electronic devices are distributed using devices such as transistors, which are also referred to as distributorless ignition systems.
The electronic power distribution system can be divided into two types: simultaneous ignition mode and independent ignition mode. At the same time, the ignition mode has a transistor with half the number of cylinders of the engine and an ignition coil. The high voltage generated by the ignition coil is connected to the corresponding spark plug by the high voltage line, so that the spark gap between the compression stroke and the exhaust stroke cylinder simultaneously jumps. The disadvantage of this method is that the spark plug exhaust stroke also needs to jump fire. When the spark is fired, the spark plug side electrode is in a negative polarity, so the spark plug electrode is easily ablated. The advantage is that the number of components used is small and the price is relatively low.
The independent ignition mode has the same number of ignition coils and transistors as the number of engine cylinders. The high voltage generated by the ignition coil is directly connected to the designated spark plug to cause the spark plug gap on the compression stroke to jump. The advantage of this method is that the system is easy to electronically control, which can reduce ignition energy loss and reduce radio interference. The disadvantage is that the number of transistors and ignition coils used is increased and the price is relatively
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