IMPROVING THE QUALITY OF GLANCING THE FRICTION SURFACES OF AUTOMOTOR ENGINE PARTS: PARAMETERS, METHODS, AND OPTIMAL CONDITIONS

Аннотация

The quality of smoothing the friction surfaces of engine parts is important for its long- term and efficient operation. In the current literature, the methods of grinding are insufficiently covered, and a unified system of indicators has not been developed. The quality of grinding is influenced by the physical and mechanical properties of the materials, the quality of processing, the lubricating material, and the conditions of friction. Taking these factors into account, optimizing the grinding process extends the service life of engine parts and increases operational efficiency. Keywords: engine, friction surface, grinding, physical and mechanical properties, lubrication, processing Introduction. The issue of improving the quality of friction surfaces depends on the quality of grinding the mechanism consisting of these friction parts, since as a result of grinding, the wear of engine parts ydecreases significantly even during the period of stable wear yof the engine's subsequent operation period. Despite the above, the methodology for polishing engine parts is not sufficiently covered in the current literature. At the same time, a unified system of indicators characterizing the quality and methods of grinding engine parts has not been developed. This circumstance can be explained by the difficulty of choosing grinding parameters and the lack of justification for the optimal conditionsfor itsimplementation [1]. Based on the above analysis, the following main factors affecting the grinding of engine parts can be identified: 1. Physico-mechanical properties ofmaterials onfriction surfaces; 2. Quality of machining of friction parts (purity of the surface, deviation from the geometric shape, etc.); 3. Type of machining of working surfaces of parts (thermal, chemical-thermal, electrical, chemical, etc.); 4. Qualityof assembly ofcontact surfaces (deviations from alignment and perpendicularity); 5. Quality of lubricating material (viscosity, degree of acidity or alkalinity, type and amount of additiveintheoil, presence offoreign mechanical impurities, theirtypes and sizes)[2]; http://www.internationaljournal.co.in/index.php/jasass 239 Volume15 Issue 08, August 2025 Impact factor: 2019: 4.679 2020: 5.015 2021: 5.436, 2022: 5.242, 2023: 6.995, 2024 7.75  ambient temperature (temperature offriction surfaces, coolant, lubricant, and oil pressure;  the speed of movement of friction surfaces relative to each other, their compatibility and theirchange overtime;  the amount of specific pressure (load) acting on the friction surface, the nature of their application, and theirchange overtime;  stagedness orcontinuity ofgrinding interms offriction speed and load;  Rolling stages: cold, hot inno-load mode, hot under load. Methodology.Fromtheabove,itcanbeseenthat,despitemanyyearsofexperienceofenginemanufacturers andrepairenterprises,theissueofenginegrindingisorganizedonthebasisofpracticalexperience. In recent decades, some research has been conducted on the issue of engine grinding. They are mainly devotedtotheselectionoflubricantusedforgrindingengine parts andthejustificationofthegrindingstage. A.L. Khokhlov, V.V. Varonkov used low-viscosity (industrial grade 12) oil in their research on the grinding of the Zil engine, as a result of which the grinding time was reduced from 55 minutes to 31 minutes, and the wear resistance of the friction surfaces during grinding on the stand increased bytwo timesa[3]. Research has shown that grinding engines at low speeds is not advisable, since in the initial period of grinding (5-10 minutes), the wear of friction surfaces increases hundreds of times compared to high speeds. Syrbakov A.P. emphasized that cold grinding of engines without loading is an unnecessary process. At the same time, theyshowed that during the grinding period, at a coolant temperature of 25oC, the wear in the engine is 5 times higher than at normal temperatures, and at 50oC,thewear is1.6times higher[4]. At the same time, great attention is paid to cold grinding of engines. According toS.P. Bazhenov, B.N. Kazmin, and S.V. Nosov, cold grinding of the friction surfaces of cylinder-piston group parts is of great importance for increasing their service life [14;92-b]. However, in most repair enterprises, repaired engines are not subjected to cold running-in, or even if they are, they are run-in using the oil used inoperating conditions. In cold rolling , the viscosity of such oils is tens of times higher than the viscosity of oils recommended for grinding. If we consider that cold grinding is carried out at low crankshaft speeds (100-300 rpm), then after repair in newly assembled engines, due to insufficient oil pressure and small gaps between the friction surfaces, thewear rate oftheparts yincreases. It should be noted here that cold rolling of engines often is carried out with the cylinder head removed, which is, of course, a mistake, since when the head is fixed in place after grinding, deformation of the cylinder a