TEST METHODOLOGY FOR ASSESSING THE OPERATING AND EXCONIC QUALITIES OF AGRICULTURAL TRACTORS PURSUANT TO OECD CODE 2

Abstract

Purpose of the study is new provisions for testing agricultural tractors, evaluating their performance, which implement the OECD Code 2 Research methods. The testing of the tractor and its main elements is based on the method of partial accelerations, the basis of which is the solution of the inverse task of the dynamics: the acting forces are estimated from the acceleration. The method and means of measurement (developed in the L. Pogorilyy UkrNDIPVT Kharkiv branch) are effectively used in testing tractors and its main elements. The results of the study. The proposed express methods make it possible to reduce the time for testing and timely identify shortcomings in the operation of the systems being tested. The proposed express test method for the cylinder-piston group provides the ability to timely identify shortcomings in the operation of engines. It has been established that the most efficient operation of the tested unit is when the tractor is not fully loaded. The stability of the movement of the transport-technological unit is interconnected with its controllability, which is determined by the technical condition of the steering. The relationship between the investigated values of the angular accelerations of the steering wheel of the tractor and the aggregated machine is provided with a reliability of 95 %. To determine the braking properties, an indicator is proposed that characterizes the growth rate of the tractor deceleration during braking. To evaluate the quality of functioning of the hydraulic drive of the tractor mounted system in the case of unstable technical condition of its elements, it is necessary to start with the evaluation of the fluid flow in the hydraulic cylinder and end with the analysis of the flow in the bypass valve. Conclusions. Code 2 of the OECD normalizes the methodology for operational testing of agricultural tractors, on the basis of which in L. Pogorilyy UkrNDIPVT Kharkiv branch developed industry standards for assessing the traction and energy performance of tractors. It has been theoretically and experimentally proved that in the performance tests of tractors and its main elements, the method of partial accelerations is effective, which is based on the reverse transition from the vector sum in the space of forces that act on the tractor to the vector sum in the space of accelerations. This method allows you quickly assess the performance of tractors when coupled with mounted and trailed agricultural machines, as well as the technical condition of the main elements of the tractor design. Keywords: tractor, tests, OECD Code 2, main elements, malfunctions, express methods