This paper presents the evaluation of a newly developing synthetic-based hydraulic fluid MOL Farm UTTO Synt, developed by MOL Group, Hungary. The fluid was subjected to a laboratory test by using a gear hydrostatic pump UD 25, which is used in the latest Zetor Fortera tractors. During the test, flow values were statistically evaluated and graphically displayed in the form of flow characteristics and the loss of flow efficiency. On the basis of laboratory test results, it can be concluded that the newly developing fluid meets the specified requirements and it is possible to continue in testing under operating conditions. Keywords: flow efficiency, hydrostatic pump, synthetic-based hydraulic fluid Abstrakt Príspevok je zameraný na hodnotenie novovyvíjanej hydraulickej syntetickej kvapaliny MOL Farm UTTO Synt, vyvíjanej spoločnosťou MOL Group, Maďarsko. Kvapalina bola podrobená laboratórnemu testu za použitia zubového hydrogenerátora UD 25, ktorý sa používa v najnovších traktoroch Zetor Forterra. Počas skúšky boli hodnoty získaných prietokov štatistický spracované a následne graficky vyhodnotené vo forme prietokových charakteristík a poklesu prietokovej účinnosti hydrogenerátora. Na základe výsledkov laboratórnej skúšky je možné konštatovať, že novovývíjaná kvapalina vyhovuje stanoveným požiadavkám a je možné pokračovať v skúškach v prevádzkových podmienkach.

Hujo Ľ., Tkáč Z., Tulík J., Kosiba J., Uhrinová D., Jánošová M. (2016): Monitoring of operation loading of three-point linkage during ploughing. Res. Agr. Eng., 62: 24-29.The research was focused on operational measurements of tractor plough tools and their subsequent utilisation and simulation under laboratory conditions by a hydrostatic simulator. In this field, theoretical and experimental works were focused on tractors, whereby the proposal of laboratory test arose out of the loading characteristics of the three-point linkage of the tractor. These characteristics were obtained from the agricultural tractor's operation in plough aggregation. Measurements were performed with the following tools: tractor with carrier-mounted four-mouldboard plough PH1-435 and tractor with Kuhn plough manufactured by. The subject of these measurements was to obtain the time courses of forces and pressures in the hydraulic system of the three-point linkage during ploughing with carrier-mounted and semi-mounted ploughs. For objective comparison of the obtained results during experimental measurements, we determined the characteristics of measurement conditions focused on physical and mechanical properties of the soil -bulk density, moisture, penetrometer resistance and slide strength of the soil.

The designed laboratory device will solve the issue of test methods of tractor hydraulics, monitoring the lifetime of hydraulic components, and testing of various oil types. The results of experimental measurements of forces and pressures in the three-point hydraulic hitch of tractor with plough allow implementing the design and simulation of operational loads of the dynamic system of tractor three-point hitch (TPH) under laboratory conditions. Theoretical and experimental works were focused on tractors. The design of test device is based on load characteristics obtained from the operation of tractor with plough. Research was focused on the use of results obtained from operational measurements of the tractor with plough and their simulation by a hydrostatic simulator under laboratory conditions. The laboratory device will enable the TPH life tests while loading with forces in the horizontal and vertical direction so that it corresponds to a practical loading process

Majdan R., Kosiba J., Tulík J., Kročková D., Šinský V., 2011. The comparison of biodegradable hydraulic fluid with mineral oil on the basis of selected parameters. Res. Agr. Eng., 57 (Special Issue): S43-S49.The paper presents a comparison of two fluids quality. The first one was mineral oil type UTTO which is commonly used in the transmission and hydraulic systems of agricultural tractors. The second one tested was biodegradable hydraulic fluid type ERTTO which could replace the toxic mineral oil. Both fluids were tested under the same test conditions using a special test device. The selected parameters of the hydrostatic pump were evaluated. The tests were evaluated according to the parameters describing the technical state of the hydrostatic pump as follows: flow efficiency, decrease of flow efficiency and cleanliness level of the fluid tested. This additional measurement verifies the test results. On the basis of the results achieved, we can state that the biodegradable hydraulic fluid exerts no harmful influence on the technical state of the hydrostatic pump. Therefore, the biodegradable fluid tested can be applied to the agricultural tractor. Has been demonstrated that the selected parameters are suitable for the evaluation of hydraulic fluid during its working performance. Therefore, these parameters will be used in the next examination of the fluid under operational conditions of an agricultural tractor.

This paper deals with the pollution evaluation of a biodegradable fluid, which was used as a working medium during the laboratory durability test of a hydrostatic pump. There was used a new synthetic biodegradable fluid MOL Farm UTTO Synt., developed and produced by MOL Group, Hungary. The fluid should have been practically used as a universal, common gear-hydraulic filling in agricultural machines. During the test, the pollution of used fluid was evaluated on the basis of cleanliness code, filtration of solid particles and ferrography. Based on results of cleanliness code, we could monitor the course of hydrostatic pump wear. After test completion, the fluid was subjected to filtration of solid particles and ferrography, where clusters of small particles and larger particles were detected. On the basis of their surface and shape, they were included in particles of adhesive wear. By the comparison method it was found that they are bronze particles located in the bearings of the hydrostatic pump used.