4.1. Features of a design

On cars families Chevrolet Niva (VAZ-2123) establish 4-cylinder engines with рядным a vertical arrangement of cylinders and the top arrangement of the camshaft, equipped with system of the distributed injection of fuel.

The engine VAZ-2123 is developed on the basis of the engine VAZ-21214 which, in turn, represents the modernised engine VAZ-21213 and corresponds to norms of toxicity of Euro II. The basic difference of these engines from the predecessor in a design газораспределительного the mechanism – the single-row chain is applied to noise decrease and гидронатяжитель chains. With the same purpose hydraulic support of valves are established. Additional difference – a lug on the block of cylinders for installation of the gauge of a detonation. The engine VAZ-21213 has been equipped by system of the central injection which did not have a function of suppression of a detonation.

The engine VAZ-2123 has almost similar design with the engine VAZ-21214 of car "Field" VAZ-21214. The basic difference in the form of an inlet path and in an arrangement of forward support of the power unit – at the engine VAZ-2123 they are established precisely on a line of the centre of gravity unlike the former engines established on support консольно.

Numbering of cylinders of the engine is conducted from a pulley of a cranked shaft. On the left side of a head of the block of cylinders about its bottom plane number of each cylinder, and also an operating procedure of cylinders (1–3–4–2) is cast.

Fig. 4.1. An engine Longitudinal section: 1 – the loose leaf of the radical bearing; 2 – the loose leaf шатунного the bearing; 3 – a cranked shaft; 4 – a pulley of a cranked shaft; 5 – a nut of fastening of a pulley; 6 – an asterisk of a cranked shaft; 7 – a chain Drive газораспределительного the mechanism; 8 – a drive cover газораспределительного the mechanism; 9 – a cover lining; 10 – the piston; 11 – a persistent washer; 12 – a lock washer; 13 – a camshaft asterisk; 14 – a cover of a head of the block of cylinders; 15 – a camshaft; 16 – a lining of a cover of a head of the block of cylinders; 17 – the block of cylinders; 18 – a cover crankcase couplings; 19 – the holder of a back epiploon; 20 – external persistent Half ring of a cranked shaft; 21 – a flywheel; 22 – an internal persistent half ring of a cranked shaft; 23 – a rod; 24 – a stopper маслосливного apertures

Engine cylinders are united together with the top part crankcase in uniform pig-iron casting – the block 17 (fig. 4.1) cylinders. In the bottom part of the block of cylinders on five support the cranked shaft 3 cast from pig-iron is established. As bearings of support of a cranked shaft, and also bearings шатунных necks thin-walled bimetallic steel-aluminium loose leaves are applied. The forward and back ends of a cranked shaft are condensed самоподжимными by rubber epiploons.

In each cylinder of the engine is available on one inlet and final valve. Final valves welded from two parts: a core from хромоникелемолибденовой steels, plates from хромоникелемарганцевой steels with наплавкой a working facet a special heat resisting alloy. Inlet valves became made from хромоникелемолибденовой. Cores of all valves are nitrated, and end faces of cores are tempered by currents of high frequency.

Fig. 4.3. The mechanism of a drive of valves: 1 – a head of the block of cylinders; 2 – the valve; 3 – the drive lever The valve; 4 – a tube of a supply of oil to hydrosupport; 5 – a camshaft; 6 – a lever hydrosupport Valve drive; 7 – a nut of fastening of the case of bearings of a camshaft and a tube of a supply of oil to hydrosupport; 8 – a rack of a stage of a supply of oil to hydrosupport

Valves move in directing plugs under the influence of camshaft cams through steel levers 3 (fig. 4.3), leaning one shoulder on spherical heads of hydrosupport 6, another – on end faces of cores of valves 2. Hydrosupport are screwed in nests of a head of 1 block. Oil under pressure to hydrosupport moves on a separate tube of 4 stages from an aperture in the case of bearings of a camshaft near an average hairpin of its fastening. As backlashes in клапанном the mechanism practically are absent, applied in the engine VAZ-21213 clamping springs of levers are excluded.

Pistons 10 (fig. 4.1 see) are cast from an aluminium alloy and covered by a layer of tin for improvement прирабатываемости. Skirts of pistons have the difficult geometrical form: on height conic, with the big basis in the bottom of a skirt, and in cross-section section – oval, with большей an axis located perpendicularly of an axis of a piston finger. Axes of apertures under piston fingers are displaced from an axis of symmetry of pistons on 1,2 mm in the right party of the engine. In flutes of pistons two are established компрессионных rings and one маслосъемное. In a flute маслосъемного rings are available through drillings through which the oil collected by a ring moves in the piston for greasing of a piston finger. With shod steel rods 23 pistons are connected to the help steel цементированных piston fingers of tubular section. Piston fingers of floating type freely rotate in the top lugs of a rod and in lugs of pistons. From axial moving piston fingers are fixed by the spring rings located in проточках of lugs of pistons.

Fig. 4.2. An engine Cross-section: 1 – oil картер; 2 – a nut шатунного a bolt; 3 – a bolt of fastening of a head of the block of cylinders; 4 – a tube of a supply of oil to hydrosupport; 5 – the lever of a drive of the valve; 6 – a hydrosupport; 7 – a cover of a head of the block of cylinders; 8 – a head of the block of cylinders; 9 – a lining of a head of the block of cylinders; 10 – an arm of fastening of the module of ignition; 11 – заглушка; 12 – a gear wheel of a drive of the oil pump; 13 – oil The filter; 14 – a lining oil crankcase; 15 – the oil pump

The camshaft 15 (fig. 4.1) pig-iron, cast, with the bleached rubbing surfaces of cams, is established in the demountable aluminium case fixed on the top plane of a head of the block of cylinders 8 (fig. 4.2 see), cast of an aluminium alloy. It is resulted in rotation from a cranked shaft by a single-row roller chain 7 (fig. 4.1 see). The Same chain results in rotation a shaft of a drive of the oil pump. The number of teeths of an asterisk of a shaft of a drive of the oil pump is reduced in comparison with the engine VAZ-21213 with 38 to 30 for the purpose of increase of giving of the oil pump.

Fig. 4.4. Натяжитель chains of a drive of a camshaft: 1 – the case; 2 – клапанный knot; 3 – a ball of the return valve; 4 – a restrictive pin; 5 – плунжер натяжителя; 6 – the volume terminator; 7 – a spring плунжера; In – the worker Cavity; With – an adjusting groove; Д – submitting from верстие; Е – a reserve cavity

The chain in the tense condition is supported pruzhinno-hydraulic натяжителем through the plastic boot, which sizes in comparison with a boot of the engine VAZ-21213 are considerably increased. Before engine start-up the preliminary tension of a chain is provided with a spring 7 (fig. 4.4), and after start-up – pressure of the oil submitted on a steel tube from an adapter under the gauge of emergency pressure drop of oil.

Oil from greasing system on a tube 4 (fig. 4.3 see) under pressure arrives in a cavity «Е» (fig. 4.4) натяжителя, further through an aperture «Д» see and клапанный the knot 2 gets to a cavity "In" where influences on плунжер 5. In the case 1 натяжителя the drainage aperture in diameter of 1 mm for release of air from a cavity «Е» is executed.

Chain fluctuations are extinguished успокоителем, as well as a boot натяжителя, made of wearproof plastic.

The head of the block of cylinders is attached to the block by eleven bolts and centered on it by two plugs. Between a head and the block the lining of disposable application made from безусадочного of a material is established. From above the block head is closed by a steel stamped cover 14 (fig. 4.1 see) under which the sealing lining from резинопробковой mixes is established.

To the bottom part of the block of cylinders through резинопробковую a lining it is attached oil картер 1 (fig. 4.2 see), closing a block cavity from below and carrying out function of the tank for oil.

Greasing system the combined: under pressure both разбрызгиванием. Radical and connecting rod bearings, support of a drive of a camshaft and the shaft of a drive of the oil pump, cams of a camshaft and the plug of a gear wheel of a drive of the oil pump are greased under pressure. The oil following from backlashes and sprayed by moving details, greases walls of cylinders, pistons with piston rings, piston fingers, a drive chain газораспределительного the mechanism, spherical heads of hydrosupport of a drive of valves, and also cores of valves and their directing plugs. The system consists from oil crankcase 1, шестеренчатого the oil pump 15 with built in редукционным the valve and маслоприемником, having the mesh filter of rough clearing of oil, полнопоточного the filter 13 thin clearings of oil with перепускным and противодренажным valves, the gauge of a control lamp of insufficient pressure of oil and oil channels.

Fig. 4.5. The scheme of system of ventilation crankcase (at the left – the top view): 1 – дрос сельный knot; 2 – a hose of the first contour; 3 – a hose of the second contour; 4 – воздухо Bringing branch pipe; 5 – a cover сапу On; 6 – an oil separator 3 – a ball of the return valve; 4 – a restrictive pin; 5 – плунжер натяжителя; 6 – the volume terminator; 7 – a spring плунжера; In – the worker Cavity; With – an adjusting groove; Д – submitting from верстие; Е – a reserve cavity

Ventilation system crankcase closed, with tap картерных gases through an oil separator 6 (fig. 4.5) in an inlet pipe. Further картерные gases go to engine cylinders where burn down. At engine work on an idling mode картерные gases arrive on a hose 2 first contours through the calibrated aperture (jet) in the case of throttle knot. On this mode in an inlet pipe high depression is created and картерные gases are effectively sucked away in задроссельное space. The jet limits volume of sucked away gases that engine work idling was not broken. At engine work under loading when throttle заслонка partially or it is completely open, the basic volume of gases passes on a hose 3 second contours in воздухоподводящий a branch pipe 4 before throttle knot and further in an inlet pipe and combustion chambers.

The system of cooling of the engine consists of the shirt of cooling executed in moulding and surrounding cylinders in the block, the chamber of combustion and gas channels in a head of the block of cylinders and an inlet pipe. Compulsory circulation of a liquid in system is provided with the centrifugal water pump with a drive from a cranked shaft with the help клинового a belt simultaneously serving by a drive of the generator. For maintenance of normal working temperature of a cooling liquid in cooling system establish the thermostat blocking the big circle of system at not heated-up engine and low temperature of the cooling liquid.

The engine power supply system consists of the electric fuel pump established in a fuel tank, throttle knot, the filter of thin clearing of fuel, a regulator of pressure of fuel, atomizers and fuel hoses. The ignition system consists of the module of the ignition established on a special arm on the block of cylinders, spark plugs and high voltage wires. The electronic block of engine management (ЭБУ) operates ignition system.