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9Висновок.
Проведено дослщження захисту даних особи-стосп в соцiальний мережах. Запропоновано структуру децентралiзованоl мереж1, яка вiдповiдаe кри-терiям безпеки особистих даних користувачiв.
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IMPROVEMENT OF STARTING CHARACTERISTICS OF DIESELS BY OIL SPRAYING
Balgabekov T.
Ph. D., associate Professor (Nur-Sultan, Kazakh agrotechnical University. S. Seifullin);
Koshmaganbetova A.
S.-lecturer (Karaganda, Karaganda economic University);
Yembergenov G.
undergraduate group 20-713-18-14 (Nur-Sultan, Kazakh agrotechnical University S. Seifullin).
ABSTRACT
Improving the performance of diesel engines is one of the most important socio-economic goals of road transport enterprises. Measures aimed at improving the technical level of transport equipment with diesel engines are part of the development program of road transport enterprises. Transport equipment with a diesel engine must meet the operational properties, the main of which are: high mobility; constant preparation for operational work; viability under the influence of various climatic factors.; useful capacity and load capacity.
The required technical and operational properties of machines are carried out due to the known output properties of each structural element of the object in question, including the power plant and its main component-the engine. Domestic and foreign engines are developing by increasing their own capacity, improving fuel efficiency and performance of diesels. Power plants to ensure the movement of transport equipment must have the necessary operational properties: sufficient power, reception, acceptable torque characteristics.
Keywords: car, motor company, high vehicle movement, road transportation, structural elements of the vehicle, the technical condition of the car, production vehicle, capacity of vehicle, loading capacity of the vehicle.
Introduction. The problem of diesel actuation is primarily relevant at low ambient temperatures, since as a result of reducing the temperature of the compression start, increasing the air flow into the gap between the piston and the cylinder, increasing the viscosity of the oil and reducing the frequency and irregularity of rotation of the crankshaft of a cold diesel, the temperature of the working fluid decreases to values at which the fuel cannot self-ignite at the end of the compression stroke.
This work provides a way to improve the starting characteristics, which is to reduce the energy consumption of the working fluid in the compression stroke by injecting oil into the combustion chamber. At the same time, sealing the gap between the piston and the cylinder liner, the oil lubricates the rubbing surfaces of the cylindrical piston group, reduces the resistance of rotation of the crankshaft and reduces wear of parts.
Methods and means of ensuring the operation of diesel engines. Engine start - up is a necessary operation before the technological process of its operation. The start is made by rotating the crankshaft from an external power source to a certain speed. The speed required to start the engine is determined by the state of the working fluid in the combustion chamber, the processes of mixture formation and ignition [1].
Starting the engine can be divided into the following processes:
1.Preparation of the engine for start-up, including use of means of simplification of start-up and thermal readiness.
2.rotation of the crankshaft from an external power source to provide compression in the cylinder.
3.Fuel supply and mixture preparation in engine cylinders.
4.ignition of the fuel-air mixture in the cylinders and, as a consequence, an increase in the speed of the engine crankshaft. Rotation of the crankshaft from an external source of energy with excess gas pressure inside the cylinders to a value that provides overcoming the total friction resistance of the engine parts, stops and the engine begins to work spontaneously.
5. engine heating at idle and partial loads [2].
The chemistry of the front processes of the working cycle of a piston engine is characterized by a system of kinetic equations of oxidation of hydrocarbon fuel. According to the theory of "explosions of heat" AI.
The conditions of the Tolstoy fire are the fulfillment of two conditions:
- the excess of the total energy with the molecules of the reactants over the activation energy;
- exceeding the rate of heat release of exothermic reactions over the local volume of the reaction.
The energy of the reactant molecules depends on the energy of the working fluid, which in turn is determined by its pressure and temperature. The temperature of the working fluid at the end of the compression stroke Tc for ignition of the fuel-air mixture in the engine cylinder should be at least 500 K, according to Ya-suhara, and to ensure a reliable start - Tc = 575. ..600 K. Velichkin I. N., Kuperschmidt V. A. Mikulin Yu. V. [5] and others offer the possibility of starting a diesel engine at approximate prices, taking the temperature Tc =
590...620 K, it is sufficient to provide ignition of diesel fuel in diesel cylinders not separated by the combustion chamber at the fuel injection angle and cyclic feed corresponding to the rated mode.
When the ambient temperature decreases, it is difficult to create the necessary conditions for starting the diesel engine. The main reasons for this:
6.reduced speed and increased unevenness of the diesel crankshaft due to increased viscosity of the engine oil, the moment of resistance and the drop in battery capacity (for diesel with ESSP).
7.due to the deterioration of the formation process (sputtering and evaporation) of fuel impurities, increasing viscosity, reducing the air charge in the cylinder, reducing the frequency and increasing the uneven rotation of the diesel crankshaft.
Due to the small volumes of the combustion chamber, a significant part of the fuel enters its walls and only a small part is sprayed in the volume. According to [7] in operation modes, the amount of evaporated fuel for the cycle is 26...28 %, this increases the ignition delay period. In extreme cases, the concentration of fuel vapor in the combustion chamber may be below the ignition limit and the engine will not start.
8.by reducing the temperature of the air entering from ambient air in a diesel cylinder, reducing the pressure end of compression, improving the heat transfer to the cylinder wall and increase the flow of air during the compression, reduce the frequency and improve the uneven rotation of the crankshaft of the diesel engine cold the temperature is reduced and, accordingly, the energy of the working fluid at the end of the compression stroke.
The total mass consumption of the working fluid is approximately 18% at a speed of 50 min for diesel 415/18, and at 200 min " reduced to 1 5%. Simultaneously with an increase in speed from 50 to 200 minutes, " the pressure and temperature at the end of compression stroke 1 increase by 67 and 11%, respectively.
The magnitude of the mass loss of the working fluid through the clearance between the piston and the cylinder (hereinafter, this term understand the geometric characteristics of the contact piston, cylinder liner and piston rings) is determined by various factors: the design of the cylinder group and its wear, the compression ratio, the current value of the temperature of the parts constituting the combustion chamber, the temperature and pressure of the working fluid, the presence and properties of the oil in the tap of the piston and cylinder.
Reducing the wall temperature by 40 ° C leads to an increase in the ignition delay period by 0.08...0,017 MS, the offset of the start of visible combustion and, as consequence, increase of maximum combustion pressure in the first cycles, which adversely affects the wear rate of the particles of the cylindrical piston, and passive, incomplete combustion of fuel in subsequent cycles.
Table 1 shows the normal operation mode and conditions for the formation of a mixture in the combustion chamber of the diesel engine at low-temperature start-up.
Table 1
Conditions of mixture preparation in the combustion chamber of a diesel engine
Name of parameter Nominal mode Trigger mode
Piston speed, m / s 5...10 0,4...1,0
The speed of the air charge, m / s 75...200 5...16
Air charge temperature at the end of compression, C 550...700 250...420
The wall temperature of the compacting chamber 200...300 - 30
Air charge pressure at the end of compression, MPa 4...5 1,5...2,5
Average diameter of fuel droplets, microns 10...30 40...60
When starting the air start, the diesel cools the air, the walls of the combustion chamber and reduces the energy of the working bodies and the corresponding changes in the characteristics of the start. For example, the temperature of the working fluid when opening the exhaust valves of the diesel engine is about 300 ° C below the start of the electric star at the air start 12chn18 / 20.
At low temperatures, the start of the diesel engine is characterized by a sharp increase in the dynamic parameters of the fuel combustion process, especially from other modes of operation in the initial combustion period. The first maximum ignition combustion pressure is 2.5 times higher than the maximum idle combustion pressure, and the sixth combustion pressure is 1.4 times higher, resulting in increased engine wear.
This study provides for the use as a means of facilitating the start of oil injection into the combustion chamber of the engine. The oil enters the gap between the piston and the sleeve, reducing the leakage of air charge and compacting it. Thus, the real compression ratio increases, the maximum temperature and pressure of the working fluid in the combustion chamber increases. In addition, the oil film on the surfaces forming
the combustion chamber reduces the loss of the working fluid by heat exchange and reduces the friction consumption in contact "piston-cylindrical sleeve". The disadvantages of this method is to simplify the start: the increase in operating costs for the fat, difficulty and higher, launch system structures, some deterioration of environmental characteristics associated with exhaust gases oil products combustion of oil. Currently, in domestic practice, the oil injection system is used serially only for diesel engines of type 6td. The oil injection device has the following components (figure 1):
- dispenser with a capacity of 250 cm3 4, mounted on the engine and designed to ensure the injection of the required amount of oil from the engine lubrication system into the cylinder;
2 air reducer with filter to reduce the pressure of compressed air from the air system from 15 to 2.5 MPa;
- electro-pneumatic valve allowing remote control of oil injection;
- The pipelines connecting 2 reducers, 3 electro-pneumklapana, 4 batchers and 5 air distributors of engines with systems of greasing and air supply.
On a Board of control devices of the mechanic-driver two working positions-the electric drive "suction of oil from KP" and "oil spraying"are established.
Figure 1-oil injection device: 1-cylinder; 2-reducer; 3-electro-pneumatic valve; 4-dispenser; 5-air distributor
During the operation of the oil transfer pump, the oil enters the cavity of the dispensers 4 and fills it. In this case, only the necessary proportion of oil remains in the dispenser, and excess oil is poured into the crank-case of the engine. After installation of the electric drive in position "oil spraying" the electropneu-moclapan 3 providing receipt of compressed air from air system through 2 reducers and 4 batchers joins.
Compressed air from the dispensers removes the oil portion in the drainage circuit of the engine air distributor. The inclusion of drainage holes of the air separator by a common annular cavity ensures simultaneous oil supply to all cylinders of the engine both when rotating the crankshaft and without rotation.
These engines are two-stroke, so their experience in developing an oil injection system is less suitable for
b-2 diesels, especially when applied to computational mathematical models of the duty cycle.
A diesel test of type 2B (size 15/16) showed that an engine with an oil injection device in gasoline reliably operates at an ambient temperature of -3 °C, and without an oil injection device, it does not operate At o °C...0, Zmpa. - a significant increase in pressure from the oil injection with respect to the start-up without oil injection of the device begins at the end of the 1st second, at the beginning of the 2nd second and continues
The oil spray device works as follows. The oil is fed through a hole in the housing into 2 tanks. When the air supply system is not working, the piston is compressed under the action of the spring 4 without passing to the bottom of the tank in 6 diffusers. When compressed air is supplied under pressure, 4 pistons rise to 2 heights...6. then through a valve 7 compressed air is supplied to the tank 2, and outputs the butter in a 6 dif-fusers. The amount of oil supplied is regulated by the tension of 7 valve springs.
The engine ran on fuel grade " A " according to GOST 305. It was carried out by a regular oil pump into the filling system, as well as into the oil injection tank. Before the tests, the characteristics of the fuel and oil were determined in order to confirm compliance with the requirements of regulatory documents. Visco-tem-perature characteristics of waste oils are shown in figure 3.
until the end of the rotation. At a positive ambient temperature, the difference in the compression pressure is 0.4...0.5 MPa. At 10 °C, the cylinder contains a flash of oil mixture (even without fuel supply).
Methods and results of the experimental study. The object of the experimental study was the engine V-84M (12CHN15 / 18), equipped with oil injection, PVV system and air launch system, including 2-object air cylinder, electro-pneumatic valve. A brief description of the diesel is given in table 2.
Table 2
Tasks of the experimental part of the study:
- indicator diagrams of compression pressure during rotation of the diesel crankshaft;
- the minimum amount of oil removed from the oil injection device into the engine cylinders required to seal the cylinder-piston hole at an ambient temperature of -20 °C and start the engine (including PVV) ;
- within reduction of pressure in cylinders with initial number from 15 to 7 MPa necessary for oil extraction and start (rotation) of the engine at ambient temperature -20 °C;
- time of receipt of oil in the tank of oil injection at work of the main oil pump after start-up of the engine and filling of the tank;
- the duration of filling the volume of the oil spray device;
- oil injection stability;
- The ability to extract oil from the MV at a temperature of 25 °C-30 °C.
brief description of diesel
Parameter Value
View diesel liquid with four-cycle, u-shaped, 12-cylinder multi-grain cooling engine with combined purge from centrifugal supercharger and inertial
Engine power without input and output resistance, kW (HP) 618 (840)
Rotation frequency, min"1 2000
Torque reserve, % 18
Weight, kg 1020
Volume of works, l 38,88
Minimum temperature for reliable engine start without preheating - 20 ^
Operating conditions (ambient temperature) от - 40 ^ pp +50 ^
Figure 2-oil-flame scheme (UMV ): 1-rod; 2-oil reservoir; 3-spring; 4-piston; 5-o-ring; 6-diffuser
The coolant temperature in the cylinder head and the diesel and oil crankcases prior to the test does not differ from the ambient air temperature by 2 °C prior to the test.
At each rotation not less than 8 full revolutions of a crankshaft shall be provided. The rotation speed was measured between 10 and 15 seconds after each rotation start. The duration of exposure between rotations at each set temperature-at least 15 minutes.
The Surat 3-milardi Tyr-temperatural siyathemba: 1-M12v2rk, 2-MTZ-10K
The minimum start temperature is determined by a series of consecutive starts (at least three) with the thermal state of the diesel engine below minus 8 with an interval of not more than 5 °C before each start. The minimum start temperature is confirmed by at least three consecutive starts. After each start, the engine is cooled to its initial state before the next start. After
switching off the supply of compressed air and the output of the diesel engine to the minimum stable idle speed, the diesel engine must operate at least 30 s, while the oil pressure must correspond to those specified in the technical conditions.
44_Sciences of Europe # 46, (2019)
3,2 ! _
2,2 --
50 60 70 80 90 100 110 120 130
п, мин"'
Figure 4-dependence of the maximum compression pressure on the rotational speed (- 20 °C. M12 B2rk oil): 1 -oil injection (Rv = 13.0 MPa, = 5 s); 2 - oil injection (RV=15.0 MPa, = 5 s); 3 - oil injection (Rv = 15.0 MPa, Tpr = 5 s); 4 - oil injection T = 5 s); 4 - oil injection (RV = 13.0 MPa, Tw = 20 C); non-greasy, after STARTING action (oil injection poured 260 g, release 145 g,
Rv = 15.0 MPa, Tjr = 5 s)
Table 3
Pressure change during engine rotation V-84M_
Ta^ipnöe maprrapbi Characteristic
Rotation frequency, min "1 Compression pressure, MPa
Low-fat butter spray device, Rv = 15 Mna 92 28,5
80 28,1
70 26,8
58 24,1
Oil in the spray unit is filled with 135 g of oil, output 65 g, Tpr = 5 s, 1st torque 96 29,5
83 28,8
72 27,5
Oil injection device without oil addition, output 10 g, Tpr = 5 s, 2nd screw, Rv = 9 MPa 50 23,5
43 21,5
Oil injection device without including oils, output 6510 g Tpr = 5 s, 3rd harness, Rv = 15 MPa 86 28,8
81 28,1
71 26,8
62 26,1
53 24,8
May burku kurylgysyna 260 g may kosyldy, 145 g shygaru, Tpr = 10 s, Rv = 15 MPa 84 30,1
77 29,5
70 28,5
64 27,1
54 26,1
Oil injection device, Rv = 15 MPa 120 30,0
110 29,6
100 28,5
75 26,1
67 23,4
A run is considered successful if it is not performed for two actions. The duration of the launch is determined by the operating time of the launcher.
The following oil change was performed during the test:
- heating the diesel up to operating temperature;
- fuelling of diesel engines and systems;
- filling the system with new brand oil;
- heating the diesel up to operating temperature;
- drain hot oil from Diesel and system, filter cleaning from oil residues;
- filling the system with new brand oil, start and operation of diesel 5...7 minutes, oil sampling for analysis.
The oil flow from the oil injection tank depends on the rotation time (Fig. 4). Output at -20 ° C is 65...This leads to an increase of pressure in the cylinder is 0.1 MPa. Oil extraction 100... Figure 2.7 shows that when
the air temperature is from 0 to 0 ° C, temperature from 0 to 0 ° C, temperature from 0 ° C. Upon increasing the duration of rotation to 20 with the maximum compression pressure does not increase. In addition, the compression pressure increases due to the increase in temperature and air pressure in the exhaust manifold, the increase in the temperature of the exhaust gases (including exhaust gases through the exhaust valves from the exhaust manifold).
As a result of the experiment, it was found that the removal of oil from the tank and its spraying into the diesel cylinder significantly affects the viscosity of the oil. At an ambient temperature of -25 ° C oil M-12v2rk becomes so viscous, the cylinders are almost not released. When filling the tank 150g of oil injection MTZ-10P according to GOST 25770, the combustion of the diesel crankshaft at a temperature of -25 °C is accompanied by the registration of the maximum compression pressure in the cylinder of 0.15 MPa above the non-spraying of oil. This confirms the release of oil from the MMS to the diesel cylinder.
The minimum amount of oil required to lubricate and seal the Cylinder-piston bore was determined indirectly by the pressure of the working fluid in the diesel cylinder. It is in the range of 10... 15 g. to the cylinder at the same time the maximum value of oil-as it is specified above 100. .. In this regard, it is recommended that the minimum amount of oil required to reduce the volume of the oil injection tank to 170 cm3 from the injection cases.
Summary.
Analysis of experimental data of diesel engine with air supply system and oil spraying in cylinder:
1.the supply of M12v2rk oil to the diesel cylinder at a temperature of -20 °C contributes to the sealing of the piston-cylinder hole when started with the help of an oil injection device. An increase in oil consumption for every 50 g results in an increase in the maximum compression pressure by 0.2 MPa.
2.oil discharge from the oil injection tank at -20 °C is 65...70g 5s scrolling crankshaft diesel results in an increase in cylinder pressure of 0.1 MPa. Oil extraction 100... 140 g of crankshaft rotation is provided for 10 s, with the pressure in the diesel cylinder increasing by 0.2... 0.25 MPa.
3.The maximum compression pressure is reached at 100 oil dredging... 120g (10... 12 g/cyl), further increase in the amount of spraying oil is impractical. The minimum amount of oil required it is recommended to reduce the volume of the oil injection tank from the injection conditions to 170 cm3.
4.spraying oil into the cylinder increases the maximum compression temperature by 18...The minimum starting frequency as a result of 22°C can be the rotation
of the crankshaft (at = -20 °C and other equal conditions)... 10 min " 1.
5.in oil M-12V2RK is used at a temperature of 6 M-12v2rk...7 °C, and oil injectors without application-2 °C.
6.removing the oil from the tank and spraying it into the diesel cylinder has a significant effect on the viscosity of the oil. At ambient temperatures below -25 ° C oil M-12vgrk becomes so viscous that the cylinders are almost not released.
7.in the case of supply at -20 °C, the filling of the oil injection tank through the valve is performed 30oC late after the pressure of 0.4 MPa GMM. The increase in the diameter of the jet from 3 to 4.5 mm and the valve stroke from 2 to 6 mm led to overtaking the volumetric oil by 8... 10 GMM refers to the time of formation of oil pressure 0.4 MPa.
8.the regularities linking the maximum temperature of the working fluid in the compression chamber with the number of sprayed oil in the cylinder, rotational speed and ambient temperature and number of spraying oil and the rotation frequency of diesel crankshaft with the value "is equivalent to" holes between the piston and the cylinder.
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