Constructive особенностиa. Nissan Almera (from 1995 to 1999 of release)
Nissan Almera service from 1995 to 2000 in N15 body
1. General information
2. The general requirements to car repairs
3. Operation and car maintenance
4. Petrol engines
5. Diesel engines
5.1. General information
5.2. Block of cylinders and krivoshipnoshatunny mechanism
5.3. Gazoraspredeleniye mechanism
5.3.1. Constructive особенностиa
5.3.2. Removal and installation of a gear drive of the mechanism of a gazoraspredeleniye
5.3.3. Removal and installation of a head of the block of cylinders
5.3.4. Dismantling, check of a technical condition and repair of a head of the block of cylinders
5.3.5. Check of a hydraulic pusher
5.4. Cooling system
5.5. Greasing system
5.6. Power supply system
5.7. Control system of the CD20 engine
5.8. Control system of the CD20E engine
5.9. System of production of the fulfilled gases
6. Transmission
7. Running gear
8. Steering
9. Brake system
10. Electric equipment
11. Body
12. Appendices
13. Electric equipment schemes
 









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5.3.1. Constructive особенностиa


Fig. 3.11. Details of the mechanism of a gazoraspredeleniye and TNVD drive: I\CD20 engine; II\CD20E engine; 1 — a pulley of a cranked shaft; 2 — the lower part of a forward cover of a drive of the mechanism of a gazoraspredeleniye; 3 — laying; 4 — the pump of cooling liquid; 5 — the right arm of an engine mount; 6 — a gear pulley of a cranked shaft; 7 — the top part of a forward cover of a drive of the mechanism of a gazoraspredeleniye; 8 — a gear belt of a drive of a camshaft; 9 — a directing roller; 10 — a tension roller; 11 — a spring; 12 — a flange;
13 — a gear pulley of a camshaft; 14 — a back cover of a drive of the mechanism of a gazoraspredeleniye; 15 — an epiploon; 16 — a shponka; 17 — a camshaft; 18 — a hydraulic pusher; 19 — crackers; 20 — a plate of a spring; 21 — an external spring of the valve; 22 — an internal spring of the valve;
23 — basic washers of springs; 24 — a maslootrazhatelny cap; 25 — the valve; 26 — an internal protective cover of a gear belt of a drive of TNVD; 27 — a gear pulley of a drive of TNVD; 28 — a gear belt of a drive of TNVD; 29 — an external protective cover of a gear belt of a drive of TNVD; 30 — the vacuum pump


In the engine the klapanny distributive mechanism with hydraulic pushers and the top arrangement of the camshaft actuated by a gear belt from a pulley of a cranked shaft is applied. The tension of a driving belt is regulated by the semi-automatic roller device. Details of the mechanism are represented on fig. 3.11.

Fig. 3.12. Details of a head of the block of cylinders:
1 — a stopper of a maslonalivny mouth; 2 — a cover of a head of cylinders; 3 — laying of a cover of a head of the block of cylinders; 4 — covers of bearings of a camshaft; 5 — a head of the block of cylinders; 6 — laying of a head of the block of cylinders;
7 — the vortical chamber; 8 — saddles of valves


The head of the block of cylinders (fig. 3.12) is cast from an aluminum alloy. The saddles of valves directing plugs of valves and vortical chambers of the Recardo Comet V type are pressed in a head. Nominal height of a head of the block of cylinders 116,6 — 117,0 mm. The maximum not planeness of a surface of interface of a head with the block of cylinders of 0,1 mm. Diameter of openings under bearings of a camshaft 30,000 — 30,021 mm. Diameter of openings under directing valves: nominal 10,075 mm, repair 11,185 — 11,196 mm.
Directing plugs of valves are made of cast iron and pressed from above in a head of the block of cylinders. External diameter of plugs: nominal 11,023 — 11,034 mm, repair 11,223 — 11,234 mm. Internal diameter 7,000 — 7,015 mm.
Saddles of valves are made of steel and pressed in a head of the block of cylinders. Parameters of facets of saddles of valves are specified in tab. 3.6.

Table of 3.6  Sizes of facets of saddles of valves
Parameter
Saddle of the inlet valve
Saddle of the final valve
Width of a working facet, mm
1,91
1,71
Corner of a working facet
90 °
90 °
Corner of polishing of the bottom facet
70 °
0 °
Corner of polishing of the top facet
0 °
0 °

Each inlet and final valve has two (external and internal) springs. Springs of inlet and final valves the identical.
Characteristics of springs of valves are provided in tab. 3.7.

Table 3.7  of the Characteristic of klapanny springs
Parameter
External springs
Internal springs
Length of a spring in working condition, mm
43,2
38,2
Length of a spring under loading, mm/N
36,1/168
32,6/80
Admissible not coaxiality of rounds, mm
2,1
1,9

Pushers of valves the hydraulic. Free wheeling of pushers: nominal 0,023 — 0,059 mm, maximum permissible 0,1 mm.
Valves are made of special steel, established in one row over cylinders vertically. Are put in action by camshaft cams through hydraulic pushers therefore adjustment of gaps in a drive is not required.
Characteristics of valves are provided in tab. 3.8.

Table of 3.8  Sizes of valves
Parameter
Inlet valves
Final valves
Diameter of a plate of the valve, mm
39,0-39,2
32,0-32,2
Diameter of a core of the valve, mm
6,965-6,980
6,945-6,960
Total length of the valve, mm
100,53-100,97
100,38-100,82

Laying of a head of the block of cylinders is produced from synthetic materials with metal inserts round cylinders. At laying installation the label of "TOP" should be turned to a head of the block of cylinders.
Laying of four sizes on thickness depending on a vystupaniye of pistons in relation to a surface of the block of cylinders is issued. The thickness is marked by cuts on an edge of laying (tab. 3.9).

Table 3.9  Thickness of laying of a head of the block of cylinders
Vystupaniye of pistons, mm
Thickness of laying of a head of the block of cylinders, mm
Final valves
Less than 0,505
1,1+0,03
0
1,15+0,03
1
0,505-0,555
1,20+0,05
2
More than 0,555
1,25+50,05
3


The camshaft is cast from cast iron, has eight cams and rotates in five bearings formed by a head of cylinders and demountable covers. An admissible axial gap of a camshaft 0,115 — 0,188 mm. Height of cams of a camshaft: inlet valves of 49,20 mm, final valves of 49,15 mm. Maximum permissible wear of 0,2 mm. Diameter of necks of a camshaft 29,0935 — 29,955 mm.
Gap between necks of a camshaft and openings of support: nominal 0,045 — 0,086 mm, maximum permissible 0,1 mm. Maximum permissible palpation of 0,05 mm.
The belt of a drive of a camshaft of the Nissan brand stretches a semi-automatic tension roller.
The drive of valves is carried out by camshaft cams through plunzher of the hydraulic pushers established directly in a head of the block of cylinders.

Fig. 3.13. Hydraulic pusher: 1 — the return valve; 2 — a camshaft cam; 3 — a pusher; 4 — the cylinder; 5 — a spring of compensation of gaps; 6 — a valve core;
And — the chamber of a high pressure; the B — suited supply of oil to a pusher; In — the accumulative chamber


The hydraulic pusher consists of two main mobile parts: actually the pusher 3 (fig. 3.13) serving at the same time in the course of work as a plunzher, and the cylinder 4. Under the pressure of a spring 5 plunzher and the cylinder are removed from each other thanks to what the gap between a cam of a camshaft and an end face of a core of the valve gets out. Filling and locking of the chamber A of a high pressure is provided with the return valve 1.

Fig. 3.14. Action of a hydraulic pusher: I\beginning of lifting of the valve; II\maximum lifting of the valve; III\gap compensation between a cam and a pusher; IV\channels in a hydraulic pusher: And — a ventilating opening; the B — suited supply of oil to a pusher;
V\the channel of a supply of oil from the oil pump


At the moment of the beginning of lifting of the valve (fig. 3.14, I), i.e. at the moment of a nabeganiye of a cam of a camshaft on a pusher end face, the return valve locks the chamber and pressure in it increases. The increase in pressure does not lead to reduction of the volume occupied by oil in the chamber of a high pressure. The pusher, thus, works as a firm body. At the moment of the maximum lifting of the valve (see fig. 3.14, II) the camshaft cam with force presses on a pusher that leads to significant increase in pressure in a pusher cavity. A small amount of oil jumps out through thinnesses between the cylinder and a plunzher that leads to compression of a hydraulic pusher as much as possible on 0,10 mm. Such compression is structurally necessary for extra earnings of pushers at distance reduction between a cam of a camshaft and a pusher end face.
Gap compensation between a cam and a pusher (fig. 3.14, III) occurs as follows. The cam of a camshaft does not press on a pusher, and pressure in the chamber of a high pressure falls. The spring plants a plunzher and the cylinder, choosing as that a gap between a cam and an end face of a core of the valve. During this moment the return valve opens, a quantity of oil arrives from the accumulative chamber in the chamber of a high pressure. This quantity depends on size of a chosen gap.
The raised shumnost of work of a drive of the klapanny mechanism after start-up of the engine is not a malfunction sign. Emergence of noise is connected with that at an engine stop the part of oil follows from a cavity of pushers. From the beginning of operation of the engine the chamber of a high pressure is filled again and noise stops. Filling of the chamber of a high pressure proceeds until the engine will not get warm to working temperature. The design of a lubricant contour of a head of the block of cylinders excludes complete removal of oil from channels after an engine stop. It provides supply of oil in pushers right after start-up of the engine and the fastest termination of noise in a drive of the klapanny mechanism.
After an engine stop from the channels going from the oil pump, oil flows down, and channels of a supply of oil to pushers remain filled with oil. In order that at the moment of engine start-up air did not arrive under the influence of pressure of oil in a pusher cavity, in channels of supply of oil to pushers there are the ventilating openings providing an automatic purge of a cavity of pushers. Besides, ventilating openings allow to reduce pressure of the oil arriving in pushers (fig. 3.14, IV and 3.14, V).
Phases of a gazoraspredeleniye of the CD20E engine are given in tab. 3.10.

Table 3.10  of the Phase of a gazoraspredeleniye of the CD20E engine
Parameter
Value, hail
The beginning of opening of the inlet valve to VMT of a step of release
14
Closing of the inlet valve after NMT of a step of compression
38
The beginning of opening of the final valve to NMT of a working course
56
Closing of the final valve after VMT of a step of release
12

Periodicity of replacement of a driving belt — through each 90 000 km of run. The shooters put on a belt, should correspond to the rotation direction.

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5.3.2. Removal and installation of a gear drive of the mechanism of a gazoraspredeleniye