资源描述
附件 2：外文原文Discussion on the engine cylinder scoring Abstract this paper pull-cylinder engine mechanism, analyze the reasons for the engine cylinder scoring and proposed measures to prevent the pull cylinder. Key words pull-cylinder engine of preventive measures In the course of the engine is often encountered in the engine cylinder scoring phenomenon, the so-called pull-cylinder, that is, engine piston rings or piston and cylinder liner surface of the work injury, nap, pull into the groove phenomenon. Pull cylinder considerable harm, pull the cylinder when the cylinder liner wear rate is high, up to several hundred times the normal, so that the piston, piston ring and cylinder liner greatly reduced life expectancy, so that the piston and cylinder liner bite, resulting in engine damage. Therefore, the master cylinder pull forming mechanism, carefully analyze the reasons for pulling cylinder to study the preventive measures to avoid pull-cylinder produces an important guiding significance for 1 The mechanism of the formation of a pull-cylinder Pull cylinder mechanism, intuitively, this means between piston or piston ring and cylinder liner locally generated heat to produce high-temperature melting ring and cylinder liner erosion adhesion between the piston and cylinder liner oil film disruption is to generate the main reason for pulling cylinder , oil film between the piston and cylinder liner, once interrupted, then the two metals to produce dry friction, high-speed relative motion due to the heat generated will exceed the melting point of metal, causing piston, piston ring and cylinder liner erosion surface of the melt adhesion, Pistons continue to exercise, the two adhesion points of the surface ablation was snapped, resulting in cylinder scoring. 2 cylinder causing the engine pulling the reasons for 2.1 Overload New machinery or just overhaul the mechanical factory there a reasonable run-in period, running-in period and can operate at full speed, speed should not exceed 80% of the speed calibration, since the run-in period, the mating surface of the most favorable working surface and lubricant film has not yet formed at this stage of large load of work, it will cause overheating and partial melting high-temperature corrosion resulting adhesion, the formation of pull-cylinder. 2.2 The gap with the piston and cylinder is too small From the sealing point of view, the piston and cylinder with the gap as small as possible, but if too small, engine work, the resulting heat to the piston, piston rings, cylinder liner thermal expansion. As the piston expansion coefficient than the piston ring, cylinder liner expansion coefficient, therefore, than the expansion of the piston cylinder after heat expansion of volume, which would undermine the oil film between the piston and cylinder liner, resulting in cylinder scoring. 2.3 engine temperature is too high As the engine temperature is too high, so that excessive expansion of the piston to eliminate with the gap, resulting in cylinder scoring. Causing the engine temperature is too high main reasons are: (1) cooling system leaks, water shortages Cylinder Head Gasket water crossings washed out or highlight the amount of wet cylinder liner does not meet the requirements, as well as wet-aging or damaged cylinder seal ring will result in leakage of cooling water. Radiator has been corrosion or damage, aging of the pipe break something, plumbing joints loose, water pump seal damage and so on, would give rise to the cooling water that leaked. In addition, the cylinder head casting itself is defective or improper use can also cause cracks leaking, causing the engine temperature is too high. (2) the use of long overload Overload the engine a long time to use, the engine will generate a lot of heat, cooling system can not disperse the excess heat, so that the engine can not maintain the normal operating temperature, so that the engine produces heat. (3) The thermostat failed, no big loop The role of thermostat is to control the water temperature in a certain range, in the water temperature is low, the thermostat off, water from the thermostat directly through the bypass pipe flow back into the cooling water pump, not through the radiator, which is the cooling water-cycle process. When the water temperature rose to a certain extent, the thermostat automatically open, the water circulating through the radiator, which is a large cycle of cooling water, if the thermostat fails, no big loop cooling water, the engine work of excess calories as heat can not be devices distributed out, the engine temperature is too high. (4) cooling water pump is damaged Forced cooling water in the engine water jacket and circulating between the radiator depends on the cooling water pump, cooling water pump is damaged, the cooling water is not circulating, the engine output also can not produce heat emitted to the atmosphere through the water cycle going, which led to the engine temperature too high. (5) watercourse or by blocking the ventilation radiator Watercourse blocked will inevitably lead to reduced water circulation, which affects the heat dissipation. Cooler air by blocking, affecting the effective thermal radiator area, effective heat dissipation area of reduced ability to decrease heat dissipation, which would make the engine caused by excess heat is not distributed the engine temperature is too high. (6) injector fuel injection advance angle is too small or too large Fuel injection advance angle is too small, so that combustion pushed back, resulting in increased complement combustion, fuel injection combustion heat generated by excessive increase in both cases will cause the engine temperature is too high. 3 oil shortage Do not check the oil quantity required, or in the work process due to loosening caused by oil leakage of oil pipes, can cause interruption of lubricating oil film, the surface loss of oil piston and cylinder, causing serious wear and tear, occurred pull cylinder, connecting rod bearings and other serious incidents burning , especially in the work process due to oil leakage, failure to make timely discovery, will have serious consequences. Caused by the surface of the piston and the cylinder fuel supply shortage of oil because there are several main areas: 3.1 Lubrication plug Lubrication System When the long-term use, there is no regular cleaning, excessive impurities will plug the oil line or oil filter, so that enough fuel cycles. 3.2 piston rings and piston scraping the edge of the oil capacity is too strong Lubricating oil capacity is too strong will scratch scratch, resulting in insufficient lubricant. 3.3 Oil metamorphic Degeneration caused by engine oil lubrication between the piston and cylinder liner deterioration in the terms, accelerated wear and tear caused pull-cylinder, resulting in deterioration of the main reasons oil are: (1) cooling water, fuel leaking into the next due to crankcase (2) mixed with too much dust under the crankcase 4 piston pin and piston assembly of tight Piston pin and piston assembly too tight, so that the piston deformation, the formation of anti-oval, changing the normal standards of space, form a partial destruction of oil film clearance is too small, causing dry friction pull cylinder overheating. 5 repair assembly error Repair assembly errors, and missed mounted piston pin snap ring or fully loaded tank, the engine piston pin sprang at work scratching caused by pulling cylinder liner. Installation, cleaning work is poor, the hard objects of metal scrap or crushed into the tank, can cause pulling cylinder. In addition, the piston rings installed wrong, install anti-, leakage may be caused by pulling cylinder installed. Of oil and gas piston ring of the sub-ring, oil ring is mainly used to scrape oil, lubricants and to evenly distributed in the inner surface of the cylinder to improve the conditions for cylinder lubrication. Gas ring main is to ensure that the sealing piston and cylinder, gas ring in general has set up one, two, three. According to the working conditions as well as the pressure difference, the Tao gas ring in the material selection and structural design is different, if the piston rings installed wrong, or omitted to install anti-loaded, are likely to result in Mifengbuyan or no role in the oil scraper , so that the inner surface of cylinder liner lubrication condition deteriorated, resulting in short of oil caused by pull-cylinder. 6 piston ring broken Broken piston ring stuck in the ring tank, will ring to lose flexibility, speed up the cylinder liner wear and tear, causing pulling cylinder. Caused by broken ring stuck due mainly to ring the opening gap is too small, the deflection piston in the cylinder, burning bad, so often in the engine running under deflagration conditions. Deflagration of the high-pressure vibrating ring impact than the material impact strength, caused by broken piston rings. Its breaking generally occurs in the first ring, followed by the second ring. Stuck piston ring is due to combustion-generated carbon deposition, particularly in channeling oil or dust, debris and other plug in between the piston and ring groove, so that piston rings stuck in the ring slot due. In addition, piston, piston rings, cylinder liner quality and materials on the pull-cylinder also has a certain impact. 7 of measures to prevent the engine cylinder scoring 7.1 and drivers to strictly observe the operational procedures Starting before they are required inspection of lubricating oil, cooling water to check for compliance, required to make up for insufficient check to determine whether the deterioration oil, lubricating oil is milky white water is generally caused by thinning and lubricating oil shows a diesel smell into the diesel oil, lubricating oil deterioration causes should be identified, removed, replace the oil. To strictly enforce the maintenance of the system, scheduled for cases of insurance, maintenance and a maintenance 2. Do not overload operation. Meng did not start after refueling door, especially in the cold winter, subject to a few minutes and then started to run low-speed operation. The event of unusual circumstances, such as low oil pressure, water temperature high, abnormal noise, etc., should be promptly removed, insisted on not sick job. 7.2 In the repair of assembly, it should be strict compliance with technical standards and technological requirements Spare parts for new ones to be used to detect one by one, to remove non-compliant spare parts to go out and can not believe that the new product is qualified product. Install cylinder, the cylinder should be flat, the pressure to the role of the middle of the cylinder, and slowly pressurized, do not use impact. After you install, testing, testing whether the cylinder and piston assembly clearance gap meet the required standards. Similarly, the detection of piston ring and groove side clearance, backlash, piston ring end gap and piston pin hole with live seat assembly clearance compliance with regulatory requirements, check whether there are cracks as well as the piston ring elastic compliance requirements, install a good Central, can be freely, without catching the phenomenon. Piston Ring Gap 3 (terminal gaps, backlash, backlash) in check is the piston rod assembly of a focus group, in particular the end-gap size is particularly important at the slightest mistake could result in pull-cylinder, ring end gap of the inspection should carried out according to process requirements, check the piston ring end gap of the process requirements are: the ring into the cylinder, the piston ring with the piston at the top of the roof into the cylinder where the top ring to the piston stroke measured at the smallest diameter, so that measurement data are correct. Carefully check the piston, connecting rod and crankshaft installation position deviation, demand technical specifications that meet standards for calibration. In the market to buy the piston, is hard to determine strengths and weaknesses, in the best pre-assembled to eliminate the stress treatment, about 60-80 degrees on the piston heating oil in 6 hours, in order to eliminate the stress, so that the piston assembly and stability before use. When installing the piston rings must be installed with a position where the Tao can not be installed wrong, loaded trans, drain installation, pay attention to directions, twist ring round incision upward, cylindrical cut down, marked side facing up, at the same time, in the loaded cylinder must be clean and processing certain lubricants, each province should be required to stagger the ring I, ring opening with the first axis of the crankshaft at 45 degrees, the remaining openings in each province by 90 degrees, 180 degrees 11 to stagger. Assembly is completed, must be approved by the thermal run-in 15 hours or so, testing run-in should be the first low-speed operation, and then medium-speed operation, should pay attention to noise, oil pressure, water temperature, etc., in determining no anomalies, and then put into production. In short, as long as we grasp the cylinder caused by pulling the reasons for the scientific management and the proper use of and strictly abide by rules to implement preventive measures, we will be able to reduce and even avoid the occurrence of pull-cylinder.
展开阅读全文