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doc. Ing. Ľubomír Hujo, PhD.
Identification number: 1182
University e-mail: lubomir.hujo [at]
Chief official - Department of Transport and Handling (TF)

Final thesis
Publications     Bodies

Basic information

Basic information about a final thesis

Type of thesis:
Habilitation thesis
Thesis title:
Design of laboratory equipment for the testing of hydrostatic transducers and hydraulic fluids used in mobile energy sources
Written by (author): doc. Ing. Ľubomír Hujo, PhD.
Opponent 1:
prof. Ing. Anton Žikla, CSc.
Opponent 2:
doc. Ing. Marián Kučera, PhD.
Opponent 3:
prof. Ing. Alexej Chovanec, PhD.
Final thesis progress:
Final thesis was successfully defended.

Additional information

Additional information about the final thesis follows. Click on the language link to display the information in the desired language.

Language of final thesis:

Slovak        English

Title of the thesis:
Design of laboratory equipment for the testing of hydrostatic transducers and hydraulic fluids used in mobile energy sources
Habilitation thesis presented describes the issue of laboratory tests solution to monitor durability of hydrostatic converter at dynamic loading by operating pressure. This paper presents specialised testing device for simultaneous testing of hydrostatic converters with possibility of parallel testing of various power carriers. By implementing of this solution, we used technical characteristics loading characteristics obtained from measurement (in some cases obtained from literature), characteristics of individual hydraulic and electrohydraulic components and performed calculation. Parallel testing device of hydrostatic converters and power carriers in two hydraulic circuits is designed to measure the flow characteristics and durability of hydrostatic converters with various power carriers. The flow characteristics in two hydraulic circuits can be measured simultaneously or individually by static and dynamic loading, with possibility of repeated simulation of operating conditions. Simultaneously, except hydrostatic convertors testing in two circuits, it is possible to examine different sorts of hydraulic fluids at laboratory test bench. Examination of biodegradable fluids is preferred. That can be used for driving of hydraulic machinery operating in environmentally sensitive areas. The test bench with proportional pressure valve is able to carry out the loading of hydraulic circuit elements with operating pressures obtained from previous operating measurement, also, cyclic stress whose frequency, amplitude and increase rate. Proportional pressure valve is an active element of electrohydraulic system of the test bench which provides continuous transfer of control signal to fluid pressure. Operating of electrohydraulic proportional pressure valve is executed by electronic control unit. To monitor the impact of two different power carriers (f. e. mineral and biodegradable fluids) to durability of convertors, it was designed the test bench with interface between hydrostatic circuit with mineral fluid and hydrostatic circuit with biodegradable fluid. This interface of hydraulic circuits is formed by mechanical connection of converters, at which primary driving hydraulic circuit can work independently. The results obtained by loading of operating pressure and temperature are able to use in engineering, especially in fields using hydrostatic machinery systems, automotive industry, agriculture and forestry.
Key words:
hydraulic convertors, test bench, laboratory measurement

Parts of thesis with postponed release:

Final thesis (final thesis appendices) unlimited
Reviews for final thesis unlimited