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Abstract. This paper focuses on review of modern energysaving technologies in hydraulic drives. Described main areas of energy conservation in hydraulic drive (which in turn are divided into many under the directions) and was established the popularity of them. Reviewed the comparative analysis of efficiency application of various strategies for energy saving in a hydraulic drive. Based on the review for further research a combined method of realtime control systems with energysaving algorithms and regeneration unit -selected for maxing efficiency in hydraulic drive. Scientific papers (40 papers), what introduced in review, is not older than 15 years in the databases "Sciencedirect" and "Scopus".

Reliability and maintenance analysis of transport machines hydraulic drives, basically focused to power units: pumps, cylinders etc., without taking in to account junction elements. Therefore, this paper proposes a research analysis on high-pressure hoses and junctions during technical maintenance. Comparative analysis of fluid behavior and energy efficiency inside non-repaired and repaired high-pressure hoses is presented in this research. Theoretical and experimental research results for hydraulic processes inside high-pressure hose is based on the numerical simulations using Navier–Stokes equations and experimental measurement of fluid flow pressure inside high-pressure hoses. Research of fluid flow dynamics in the hydraulic system was made with main assumptions: system flow rate in the range from 5 to 100 l/min, diameter of the hoses and repairing fitting are 3/8". The pressure drops, power losses, flow coefficients at non-repaired and after maintenance hose was obtained as a result. Simulation results were verified by running physical experiments to measure the pressure losses.

With the development of engineering materials, as well as the growing requirements for weight reduction and the reduction of energy consumption by mechanical systems, attempts have been made to utilize composite materials in the design of hydraulic cylinders. In many cases, the reduction in the weight of the actuators may lead to a reduction in the values of bending moments acting on the booms of working machines, as well as leading to a reduction in the power demand in drive systems. The use of composite materials can also increase the reliability of cylinders in corrosive environments and places with strong electromagnetic fields. This paper presents the development of hydraulic actuators made of composite materials, presenting both the achievements of research centers and commercial companies. The main research and engineering problems are presented along with the methods of solving them resulting from the literature available. The directions for further research that should be undertaken in order to increase reliability, improve efficiency, and reduce weight are also outlined.

The article presents the findings of theoretical and experimental research on hydraulic processes occurring in the hydraulic drives of transport machines. The paper analyses the influence of hydrodynamic processes on the flow characteristics of fluid considering different hydraulic fitting connections. The performed analysis is based on numerical simulations using Navier–Stokes equations for the velocity field. The dynamics of fluid flow in the hydraulic system has been investigated taking into account the main parameters like system flow rate in the range of 5 to 100 L/min, the diameter of the pipeline making 1/2” and fitting standards DKOL, ORFS, BSP and JIS. As a result, pressure drop, power losses, resistance and flow coefficients at different fitting connections have been obtained. The article compares the provided results with the findings given employing the calculation method for the standard of equivalent length fitting. To simulate fluid flow, a mesh independence study and turbulence calculations have been performed. Simulation results have been examined conducting physical experiments on measuring pressure losses. Each experimental research includes three measurements of connections bearing in mind each fitting standard.

This paper presents the concept of an expert system supporting the decision-making process of rational energy consumption by an electric car. The driving style and the average speed achieved are very important in terms of the driving range. In addition, the influence of ambient temperature on the efficiency of the electric vehicle and ultimately on energy consumption is very important. The proposed system, based on the method of multi-valued logic trees, allows minimizing the objective function, which is aimed at minimizing the energy consumption of an electric car at different ambient temperatures. The generated decisions, directed to the energy management system, can be processed in a variety of temporal and situational dimensions. The application of the system can also provide prompts to the driver on how to adjust the driving style by operating the accelerator and brake pedal. The expert system is an open system, allowing for further generalizations and modifications.

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