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Engine details
The block of cylinders of the engine: here all rotating and shaking elements krivoshipno-shatunnogo the mechanism and system of oil maintenance are collected. In the periphery the starter and ignition system bears as well auxiliary units, such as the generator, сервонасос. Blocks of cylinders of engines Duratec are cast from aluminium, grey pig-iron in honour at DuraTorg DI.
Head of the block of cylinders: in modern engines as a whole it is made today of alloys of easy metals. The head of the block of cylinders closes from above the engine block, in it there are inlet and final channels, water channels, oil channels, plug-in rings of saddles of valves, клапанные directing, installation sites of bearings of camshafts and other drives of valves, combustion chambers, and also an aperture for spark plugs and atomizers. From the oil, a cooling liquid and "extraneous" air from within and outside герметизирует a lining of a head of the block of cylinders of the engine, had between the block of cylinders and a head of the block of cylinders of the engine.
The cylinder: in it the piston between the bottom dead point (UT) and the top dead point moves (FROM): working surfaces of cylinders on the diameter are strictly co-ordinated with diameter of pistons and in addition surfaces are in special way processed. They are cooled indirectly through cooling channels or, at wet sleeves of cylinders, directly washed by a cooling liquid.
The piston: moves in the cylinder and transfers energy of combustion by means of a rod to a cranked shaft. Pistons consist of especially easy and heat resisting alloys from easy metals. Their basic components are: the bottoms, ring zones with piston rings, apertures for a piston finger and a directing part. The piston finger connects the piston to a rod. The top piston ring (a sealing ring) condenses the combustion chamber almost gas-tightly from krivoshipno-shatunnogo the mechanism. The bottom ring (scraper маслосъемное a piston ring) takes away superfluous lubricant oil from cylinder walls to the collection for the fulfilled oil (oil картер).
Rod: connects the piston to cranked shaft. It consists from: rod heads (conducts a piston finger), core, the basis of a core of a rod and a basis cover (the basis and a cover surround шатунные necks of a cranked shaft with loose leaves of bearings).
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The krivoshipno-shatunnyj mechanism: |
Cranked shaft: by means of «a binding element of a rod» will transform kinetic energy (movement of the piston from ВМТ to НМТ) to rotary energy (rotary motion). The modern cranked shaft consists of a shod core which rotates in radical loose leaves of bearings of the block of cylinders. Depending on quantity of cylinders with strictly certain shift (angular degrees) two cheeks of a crank conduct each time to шатунным to necks (to the locations шатунных bearings).
Four-cylinder cranked shaft Mondeo possess five radical bearings and four, экцентрично located under corners 90 ° шатунными bearings. Replaceable three-componental bearings of sliding "are inserted" into all locations of bearings. V6 it is enough to have 4 radical bearings, here places шатунных bearings settle down экцентрично with corners 60 °.
Valves: in the four-clock engine are intended for management of gas exchange (всасывание, compression, combustion, pushing out). In engines Mondeo valves "hang" V-shapedly at an angle 42 ° under camshafts. All moving details in a head of the block of cylinders complete a drive of valves.
Camshaft: opens and closes valves – depending on frequency of rotation of the engine and position of pistons – in strictly set time sequence.
The basic concepts of technics of engines
Four-cycle principle:
Admission (1st step): the piston slides from the top dead point (ВМТ) to the bottom dead point (НМТ). The inlet valve opens, топливовоздушная the mix directs in the cylinder.
Compression (2nd step): the piston slides from ВМТ to НМТ and at the moving compresses the let in fresh fuel mix. The inlet valve and the final valve are closed.
Combustion (3rd step): already in the beginning ВМТ the compressed fresh fuel mix ignites from igniting sparks of spark plugs: the mix burns down взрывообразно, owing to increase of pressure the piston is displaced in НМТ. The rod transfers energy further to a cranked shaft and results it in rotation.
Release (4th step): the rotating weight of a flywheel moves the piston from position НМТ again to position ВМТ. The final valve is already opened, so the burnt down gas (the fulfilled gas) leaves in an exhaust system. In aggregate these four steps in the four-cycle engine form a gas exchange cycle.
As a whole the diesel engine functions on the same principle. However on a step of an admission it soaks up only pure air, compresses it much more strongly so that injected in the end of a step of compression fuel (diesel fuel) in hot air without compulsory ignition (igniting sparks) could ignite independently. Other cycle of gas exchange is identical with the carburettor engine.
Working volume: space which takes place the piston at the movement from НМТ to ВМТ. The combustion chamber is not connected in any way with working volume. The working volume and the combustion chamber together form cylinder volume.
Compression degree: the parametre defining, the soaked up fresh gas mixture in the combustion chamber is how much compressed. The size of the chamber of combustion has direct influence on compression degree. Compression degree specifies in what volume of a fuel mix at 100 %-s' filling (throttle заслонка it is completely open) by the time of ignition should be in the combustion chamber. At engines DuraTorg compression degree makes 19,0. Engines Duratec-HE work with compression degree 10,8:1, and V6 compresses a fresh fuel mix in the relation 9,8:1 (ST220 10,25:1).
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The working volume 2 is stretched from top 1 to the bottom dead point 3. Between ВМТ which in the right cylinder is limited directly to the piston bottom, and the deflection of a head of the block of cylinders 5 forms the chamber of combustion 4. |
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