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Product Description
In the high-speed gasoline engine of modern automobile, the ignition system controlled by microprocessor has been adopted, which is also called digital electronic control ignition system. This ignition system consists of microcomputer, various sensors and ignition actuator.
In fact, in modern engines, the two subsystems of gasoline injection and ignition are controlled by the same ECU and share a set of sensors. The sensors are basically the same as those in the electronically controlled gasoline injection system, such as crankshaft position sensor, camshaft position sensor, throttle position sensor, intake manifold pressure sensor, knock sensor and so on. Among them, the deflagration sensor is a very important sensor for electronic control ignition (especially for the engine with exhaust gas turbocharger). It can monitor whether the engine deflagrates and the degree of deflagration, and as a feedback signal, make the ECU command to realize the ignition advance, so that the engine can achieve high combustion efficiency without deflagration.
Digital electronic control ignition system (ESA) can be divided into distributor type and distributor-free type (DLI) according to the structure. Distributor-type electronic control ignition system only uses one ignition coil to generate high-voltage electricity, and then the distributor ignites the spark plugs of each cylinder in turn according to the ignition sequence. Because the on-off work of the primary coil of the ignition coil is undertaken by the electronic ignition circuit, the distributor has cancelled the breaker device and only played the role of high-voltage electricity distribution.
Double cylinder ignition
Dual-cylinder ignition mode means that two cylinders share one ignition coil, so this ignition mode can only be used in engines with even number of cylinders. If, on a 4-cylinder engine, when the pistons of two cylinders are approaching the top dead center at the same time (one is compressing and the other is exhausting), two spark plugs share the same ignition coil and ignite at the same time, at this time, one is effective ignition and the other is ineffective ignition. The former is in the mixture of high pressure and low temperature, and the latter is in the exhaust gas of low pressure and high temperature, so the resistance between the two spark plug electrodes is completely different, and the energy generated is also different, which leads to much more effective ignition, accounting for about the total energy.
Separate ignition
The independent ignition method is that each cylinder is assigned an ignition coil, which is directly installed on the top of the spark plug, thus eliminating the high-voltage line. This ignition method can realize accurate ignition by camshaft sensor or by monitoring cylinder compression. It is suitable for engines with any number of cylinders, especially for engines with 4 valves per cylinder. Because the ignition coil combination of spark plug can be installed in the middle of DOHC, the clearance space is fully utilized. Because the distributor and high-voltage line are cancelled, the energy conduction loss and leakage loss are very small, and there is no mechanical wear. Moreover, the ignition coils and spark plugs of each cylinder are assembled together and wrapped with metal, which greatly reduces the electromagnetic interference and can ensure the normal work of the engine electronic control system.
