12131703228 BMW Ignition Coil 0.25KG BMW 3 Series 12131748017

Ignition system ignition coil 12131748017 12131703228 for BMW 3 Series

Three types of ignition coils

Digital Electronically Controlled Ignition System (ESA) is divided into two types: distributor type and non-distributor type (DLI) according to the structure. The distributor-type electronically controlled ignition system uses only one ignition coil to generate high-voltage electricity, and then the distributor follows the ignition sequence

is ignited by the spark plugs of each cylinder in turn. Since 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 plays the role of high-voltage power distribution.

two-cylinder ignition method

Dual-cylinder ignition method refers to the combination of two cylinders with an ignition coil, so this ignition method can only be used on engines with an even number of cylinders. If on a 4-cylinder engine, when two cylinder pistons approach top dead center at the same time (one is for compression and the other is for exhaust), the two spark plugs share the same ignition coil and ignite at the same time. At this time, one is effective and the other is Ineffective ignition, the former is in the high-pressure and low-temperature mixture, and the latter is in the low-pressure and high-temperature exhaust gas. Therefore, the resistance between the spark plug electrodes of the two is completely different, and the energy generated is different, resulting in a much larger effective ignition energy. , Accounting for about 80% of the total energy.

Single ignition method

Single ignition method is to allocate an ignition coil to each cylinder, and the ignition coil is directly installed on the top of the spark plug, which also eliminates the high voltage line. This ignition method achieves precise ignition by camshaft sensors or by monitoring cylinder compression. It is suitable for engines with any number of cylinders, and is especially suitable for engines with 4 valves per cylinder. Because the spark plug ignition coil assembly can be installed in the middle of the double overhead camshaft (DOHC), the gap space is fully utilized. Due to the elimination of distributors and high-voltage lines, the energy conduction loss and leakage loss are extremely small, and there is no mechanical wear. Moreover, the ignition coil and spark plug of each cylinder are assembled together, and the outer metal is wrapped, which greatly reduces electromagnetic interference and can ensure the normal engine electronic control system.

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