A SYSTEM APPROACH FOR ASSESSING PERFORMANCE IN AGRICULTURAL TRACTORS

Purpose of the study. Formation of a methodology for systematic evaluation of performance in agricultural tractors. Research methods. The methodological basis for evaluating the performance of agricultural tractors is the OECD Code 2. Code 2 of the OECD standardizes test methods. Determination of traction indicators for tractors is carried out by the method regulated by the SOU L. Pogorslyy UkrNDIPVT 71.2-37-046043090-017:2015. A measuring and registration complex is used. When evaluating the functional accuracy of the tractor, according to DSTU 7463:2013, indicators are analyzed that determine the traction class of the tractor, energy capabilities and aggregation. An analytical method and a comparative analysis with the results of experimental studies are used to form a scientific problem, determine the purpose and set the objectives of the study. The results of the study. The research results develop a methodology for a systematic approach to assessing the operational quality of agricultural tractors. Direction of research to improve the technical, economic and agro technical properties. New dependencies are proposed (they use the method of partial accelerations) for estimating the traction and energy performance of the tractor, handling and driving stability, and braking properties. A technique for estimating the dynamic properties of a tractor as part of a tillage unit in an unsteady mode of its movement on the rut is substantiated. Code 2 of the OECD standardizes the testing methodology for agricultural tractors regarding the evaluation of their performance under nominal technical condition. The results of the studies that are given in the article prove that the deviations of real functional parameters from the nominal ones significantly affect the performance of the tractor. Conclusions. According to the results of the research carried out, the classification of the performance of agricultural tractors was carried out according to their traction and agro technical properties. The research results made it possible to formulate the main theoretical and scientific-practical conclusions. A methodology for a systematic approach to assessing the performance of agricultural tractors has been formulated, based on the substantiated method of partial accelerations. Using the method of partial accelerations, the dependences of the effective power of the engine, the efficiency of the tractor, the mass and resistance of the agricultural machine aggregated with the tractor, the braking properties of the tractor, its controllability and driving stability on the rut are substantiated. Analytically proved and experimentally confirmed the instability of the traction force of the tractor, the resistance of the agricultural machine of the tillage unit, the dynamic performance of which exceeds the average values by 2.5-3.0 times. Keywords: tractor, system approach, operational properties, traction properties, controllability, braking properties.