Alimova Z.X., Bakhytzhan K.Sh.
Tashkent State Transport University, Uzbekistan M. Auezov South-Kazakhstan University, Doctor of Technical Sciences, Professor

Abstract. Recently, much attention has been paid to the study of the influence of climatic conditions on the performance of mining transport equipment in quarries. Studies of motor oils operating in engines of heavily loaded mining transport equipment during operation in hot climates (air temperature in summer exceeds +50 C) and high dust levels show that motor oils are intensively contaminated with mechanical impurities. The Muruntau quarry is a unique mountain site. Its depth today is more than 620m. The width is more than 2.9 km and the length is more than 3.2 km. The length of quarry roads is 65-70 km. Due to rarefied air, the power of diesel engines is reduced by 20-25%; the insulation on the engines quickly ages and fails. The purpose of this work is operational research of the quality of motor oils of dump trucks operating mining transport equipment. For this purpose, the characteristics of working motor oils SAE15W-40, API CI-4/SL selected from the engine of CAT-789D dump trucks were determined.

Keywords: motor oil, oxidation, contamination, deposits, durability, dustiness

Introduction: 
    The development of the global industrial complex and, in particular, the branches of mechanical engineering, constantly requires an increase in the production of metallurgical products, which, in turn, is accompanied by an increase in the production of relevant minerals. Special technological processes of extraction and processing of significant volumes of soils have been developed. Special equipment and techniques have been developed to implement these technologies. In particular, heavy-duty vehicles with a lifting capacity of over 120-150 tons or more are used to transport the extracted materials.
    Recently, much attention has been paid to studying the influence of climatic conditions on the operation of mining equipment in quarries. Muruntau quarry is a unique mining facility. Its depth today is more than 620 meters. The width is more than 2.9 km and the length is more than 3.2 km. The length of the quarry roads is 65-70 km, the amount of dust increases to 10-50 g/m3. The experience of developing the Muruntau high-altitude quarry shows that rarefied air, low oxygen levels, low atmospheric pressure, air ionization and solar radiation negatively affect the performance of engine oils in dump trucks. Due to the thin air, the power of diesel engines is reduced by 20-25%, productivity is reduced by 20-25%, and engine insulation fails. When directly exposed to low atmospheric pressure, the sealing conditions deteriorate and the sealing performance of bearings and other parts with liquid lubricants decreases.
    Low and high air temperatures, together with the corresponding humidity, affect the resistance to the destruction of the air gap at a given air pressure. Studies of lubricating oils used in engines of highly loaded mining equipment, when operating in hot climates (summer air temperature exceeds +50°C) and high dust levels show that lubricants are intensively contaminated with mechanical impurities, water, fuel and organic products, which leads to premature aging of the oil. The high thermal load on the parts of the forced engines, with which the engine oil has to come into contact, and the interaction with gases entering the crankcase from the combustion chambers dramatically worsen their operating conditions. Today, the analysis of operational lubricants is one of the most effective modern methods for diagnosing the condition of mining machinery components and aggregates and their degree of wear. The purpose of this work is to study changes in the performance of motor oils of dump trucks operating mining and transport equipment.
    For this purpose, the characteristics of SAE15W-40 and API CI-4/SL working engine oils selected for CAT-789 D dump truck engines were determined. The Cat 789 mining dump trucks have the lowest cost of transporting a ton of equipment in their class. The dump truck is equipped with a powerful engine of its own design, the Cat 3500 series (3516C EUI). It has 16 cylinders and an increased piston stroke, which ensures more complete combustion of fuel.
    The engine is designed for heavy loads and develops high power at low RPM. Taking into account the above features, the operating conditions of oils in dump truck engines are defined as more severe than in passenger car engines. This requires strict adherence to the oil and oil filter change intervals specified in the manufacturer's specifications. The engines of mining dump trucks operate in very difficult conditions - in places with extremely low or high temperatures. Therefore, the oils for this equipment must contain components that maintain the performance characteristics of the oil for a long time, despite difficult operating conditions. For this method, it is necessary to use special oils with high dispersing properties.