Експериментальне дослідження можливості використання силікатної пасти для підвищення довговічності деталей автомобільних двигунів

Abstract

The study of the possibility of using silicate abrasive paste to increase the durability of car parts is considered on the example of the "valve-seat" connection of the gas distribution mechanism of the internal combustion engine. The service life of the gas distribution mechanism is mainly determined by the wear of its links, therefore, to increase its durability, it is necessary to ensure high wear resistance of its parts (valve and seat). As a result of wear and tear of parts, technical and economic indicators of the engine deteriorate. A drop in engine power occurs because of a loose fitting of the valve in the seat and gas breakthrough. Therefore, the operating conditions of the connected friction pairs of the gas distribution mechanism depend on the quality of the friction surfaces, on the changes that occur on the surfaces in contact, in the friction process in the presence or absence of lubricant, and on the nature of wear. When restoring the "valve-seat" connection, the final treatment for eliminating defects is rubbing with abrasive pastes. The paper presents the results of an experimental study of the possibility of using silicate paste to increase the durability of parts during their restoration. To determine the durability of parts whose surfaces were treated with abrasive pastes, a study of the wear resistance of such surfaces was conducted. For this purpose, the anti-friction properties and load capacity of surfaces treated with silicate paste and existing compositions (abrasive with oil and "CT") were determined. For the processing of friction surfaces, a laboratory installation was used, which is mounted on the bed of a universal machine designed for lapping the valves of auto tractor engines. Research on determining the antifriction properties and load capacity of surfaces treated with abrasive pastes was carried out on a special face friction unit. The conducted research confirms that in the process of treatment with a silicate abrasive composition, a surface close to optimal is formed, which causes a low coefficient of friction, temperature, and intensity of wear and this occurs due to the formation of amorphous silica (SiO2). It has been proven that the best anti-friction properties have a friction pair that is treated with an abrasive silicate composition, and this will increase the durability of car engine parts by 15-20%. It was established that the friction pair, which is treated with an abrasive silicate composition, withstands the load before seizing 1.8-2 times more than the friction pairs, which are treated with existing compositions.