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Ignition турбодвигателя 1,8 l capacity of 110 kw: each cylinder has an own coil of ignition (1–4). The spark should slip in the combustion chamber in the fullness of time. Combustion of a toplivno-air mix occurs most effectively while it is compressed to the most minimum volume. This maximum compression is reached during that instant when the piston at end of a course of compression wishes to pass from progress to return movement of a working step. Before the piston passes to movement in the opposite direction, a share of an instant it is in the highest point of a trajectory of the movement. This point name «the top dead point» (ВМТ) . So, the ideal moment of ignition is that moment when the piston only begins the return movement. The compression maximum, and the piston can be wrung out with force to the engine block. Despite it, would be wrong to establish the ignition moment precisely in the top dead point. As certain time (nearby 1/3000) before its ignition and development of a total pressure of combustion is required to a toplivno-air mix. Therefore the ignition moment is established for earlier term. We speak about «an ignition advancing». Therefore the starting shot for a spark sounds even during piston movement upwards, and pressure of combustion develops right after ВМТ . The top dead point and ignition advancing With increase in number of turns of the engine the ignition spark should slip all earlier since – as it was already told – the toplivno-air mix always needs the same time for ignition. Only so combustion process precisely in due time namely when the piston again only starts to move back is carried out. Combustion of a toplivno-air mix depends also on its structure. At slightly wrung out pedal of gas (at «partial loading») a mix in combustion chambers possesses the lowered ability to ignition, therefore it burns down more slowly and for this reason ignition too should work with the big advancing. Installation of ignition with delay In other situations it is necessary to shift the ignition moment in "a delay" direction. Ignition occurs when the piston passed for a long time already the top dead point. I.e. ignition is carried out almost on an exhaust step that improves structure of the fulfilled gases, but worsens capacity of the engine.