No abstract

The basis of automotive equipment used in agricultural enterprises are tractors, cars and self-propelled combines. They are equipped with internal combustion engines, the design feature of which is the presence of replaceable, so-called “wet” cylinder liners. Nevertheless, engines with an integral cylinder block design have also found applications at the enterprises of the agriculture-industrial complex. It is important to develop a mathematical model that allows calculating the force of pressing the sleeve into the block, while designing the technological process of cylinder block linings for such engines. Regarding this, the Department of energy resources and technical services in Vologda State Dairy Academy Named after N. V. Vereshchagin conducted an experiment, which is based on force measurement for press fitting the sleeve into the engine block and comparison of the measurement results with the results of theoretical calculations according to Lamet formulas. Relying on the results of the experiment, the method (Lamet formula) is deemed to be applicable to determine the force of pressing the sleeve into the engine cylinder block with optimal tension, which is valid for thick-walled cylinders.

Nowadays, a case-by case approach to optimizing and rationalizing the machine usage parameters is relevant. One of the ways to improve the efficiency of the machine and tractor fleet operation with regard to individual reliability indicators is to assess the rational tractor service life. According to the proposed model, the tractor is to be decommissioned when it ceases making a profit. Aiming to test the proposed model, ten 3 kN class tractors, operated in agricultural enterprises in the Vologda district of the Vologda region, have been under research for five years. As a result, it has been found out that all the tractors under study have different reliability and, consequently, different rational service life periods.