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Reducing energy consumption and increasing operational efficiency are currently among the leading research topics in the design of hydraulic systems. In recent years, hydraulic system modeling and design techniques have rapidly expanded, especially using artificial intelligence methods. Due to the variety of algorithms, methods, and tools of artificial intelligence, it is possible to consider the prospects and directions of their further development. The analysis of the most recent publications allowed three leading technologies to be indicated, including artificial neural networks, evolutionary algorithms, and fuzzy logic. This article summarizes their current applications in the research, main advantages, and limitations, as well as expected directions for further development.

Flow control valves are designed to maintain a constant flow rate regardless of pressure changes. However, standard, two-way design may cause significant energy losses due to the need to maintain high pressure in the supply line. In contrast, the proposed three-way valve allows the required flow rate to be obtained at a supply pressure slightly above the loading pressure. This work included building mathematical and simulation models, conducting numerical simulations in Ansys/Fluent and Matlab/Simulink environments, and verifying the results by initial test bench experiments on a valve prototype. The main contribution provided by the work concerns the proposal of a new valve solution and the estimation of its operational characteristics.

This article presents a proposal and a numerical analysis of a hydraulic system consisting of one constant capacity pump supplying multiple receivers in the form of hydraulic motors, based on the example of a rail grinder. The proposed approach requires splitting the stream of the working fluid, which was achieved using 2-way flow control valves. As part of the preliminary CFD studies, the pressure and velocity distributions of the flow control valve were obtained, and the discharge coefficient of the valve nozzles was determined as a function of the valve spool position. Then, a mathematical model of the system was formulated, which was used to build a simulation model in the Matlab/Simulink environment. Next, the ability of the system to achieve the assumed operating parameters and its energy efficiency in a given load range were tested. The results indicate that the system can effectively perform the required work cycles with sufficient accuracy.

Reliability is a key feature in engineering systems and might be improved by using preventive methods, which allows for identification potential failures and establishing cause-and-effect relationships in consistent and systematic way. One of the popular quality improvement method is FMEA (Failure Modes and Effects Analysis). An application of matrix FMEA analysis method on example of flow control valve has been presented and discussed in the work. Presented example shows also a different ways of evaluating failures and theirs influence on analysis results.

This article presents results of numerical modelling, simulation and test bench experiments of a hydraulic direct-acting relief valve was used as a safety valve. The analyzed safety valve was placed in a system consisting of a fixed-speed pump, a control valve, a hydraulic cylinder as an actuator and a second pressure valve in the load line used as a payload generator for the cylinder. In the first step mathematical model of the system was formulated in the form of a system of ordinary differential equations. Next, simulation model was created in Matlab/Simulink. Simulations were carried out for different values of the actuator payload. The obtained results include time series of pressure, flow rate and displacement of the actuator piston. In order to confirm simulation results, a test bench was built and series of experiments were carried out. High compliance of simulation and laboratory results was obtained. It was confirmed that the proposed solution with the relief valve used as a safety valve fulfills its task of protecting the hydraulic system from excessive pressure increase.

The article presents a study of the flow through a tunable check valve used as a hydraulic lock in a system with an actuator. Special attention is given to energy losses of the liquid stream in the poppet gap. In the first stage of the research, CFD methods were used to determine the speed and pressure distributions for the fixed values of the input flow rate and the poppet position. The values of the jet angle and pressures determined based on the CFD results were used to build a simulation model of the entire hydraulic system in Matlab/Simulink environment. The influence of the spring parameters pressing the poppet against the valve seat on the pressure drop and thus on the amount of energy lost was investigated. In particular, the spring stiffness and initial tension were studied. The obtained results were used to develop guidelines for constructing a valve prototype. Finally, the results of simulation tests were verified based on the actual valve characteristic obtained on a test bench.

Hydraulic systems are widely used in drive and control systems of multiple devices. Various types of control valves are used to determine the appropriate direction of the working fluid movement. This article provides flow analysis of a two-way hydraulic control valve in a cartridge housing. The flow rate through the valve is controlled by a spring and an electromagnet. Design of a poppet ensures tightness in both directions in the cut-off position. Accordingly, there is no need to use additional shut-off valves. However, the fluid stream entering the valve is divided into several jets, due to the cartridge design. This makes the flow complex and difficult to be modelled. Therefore, the advanced ANSYS/Fluent software was used to carry out the analysis. The conducted tests allowed the influence of selected geometrical and physical parameters on the valve characteristics to be examined.

Proportional control valves are characterized by smooth opening of flow channels by means of the spool control. At the initial stage of opening, the flow gap is of a small cross-section which then gradually expands. This enables smoother start-up of a device as well as more precise control of the working motion compared to conventional control valves. Among the electromagnetically controlled proportional control valves, some complex solutions equipped with spool displacement transducers, compensating valves, advanced electronics, etc. can be distinguished. This allows compensation for the harmful effects of flow-related forces.

Flow control valves are commonly used in fluid power systems. Controlled by proportional solenoid allows to control flow rate irrespective of pressure on inlet or outlet of the valve. Simulation of such valve is complex task due to the usage of throttle and compensating valves inside one housing. This work presents an attempt of using CFD simulation with implemented Fluid Structure Interaction for simulation of flow control valve under changeable working conditions.

The main objective of this article was to analyse flow forces acting on a spool of a proportional control valve in the initial phase of the spool gap opening. Accordingly, modification of the spool geometry has been proposed in order to reduce flow force values. The modification consisted in making small circular undercuts at the apex of main triangular grooves, which were made on the spool. The undercuts were made in order to improve flow characteristics, for the gap width less or equal to 0.40 mm. Two arrangements of undercuts were tested. In the first version the undercut was made only on one groove, while in the second version two undercuts were located symmetrically on both sides of the spool. Simulations were carried out by the means of CFD methods and allowed both axial and radial flow forces to be determined. The simulation results showed that the use of a single undercut allowed the valve to operate at a very low flow. However, a significant radial force asymmetry appeared. The use of symmetric undercuts reduced the unevenness of radial forces, with a relatively small increase in flow rate and axial force. The obtained axial force values were next verified experimentally on a test bench.

The main objective of this article is to analyse flow coefficient of a proportional directional valve with integrated spool position controller. The valve geometry has been modified by creating additional undercuts on the spool, which provide improved flow characteristics, especially at low flow rates. The analysis consisted of two phases, including computer simulations and test bench experiments. At first, flow through the valve was simulated by the means of CFD method in ANSYS/Fluent software, assuming the fixed spool positions. Based on the results, flow coefficient values were determined. The results showed, that in the examined gap width range, the coefficient value is mainly related to the spool position, and to a lesser extent to the volumetric flow rate. Hence, a proposal to formulate the flow coefficient value as a function of spool position or spool position and flow rate was made. Three approximating functions were determined in Matlab system on the basis of the obtained CFD results: a linear curve μ = f ( x g ) , as well as a linear polynomial surface and a quadratic polynomial surface μ = f ( x g , Q ) . Next, the results were verified by experiments conducted at a test bench. The best fit flow coefficient function was then used in the subsequent simulations on a multi-actuator system comprising three parallel-connected valves supplied by a single pump. In this case, each valve was set a different fixed spool position, which resulted in a different throttle gap width. Analysis of the system was carried out using an own-developed computer software for solving the analytical equations. Finally, the results were compared to those obtained by means of a CFD method, and a satisfactory compliance was achieved.

The main objective of this article is to analyse the flow characteristics of a proportional flow control valve and to improve its characteristics by means of geometrical modifications of the valve spool. As the first step, a geometrical model of the valve was built in a CAD system and flow analyses were carried out using CFD methods. Two types of openings in the spool were tested: a round and a triangular one. Simulations were conducted with various values of throttle gap width, flow rate and input pressure. Based on the obtained results, the jet angle was determined as a function of throttle gap width for both types of openings. Then, a mathematical model of the valve was formulated. Based on the mathematical model, a simulation model was built in Matlab/Simulink. The results of the simulation results showed that the use of triangular openings in a throttle valve spool instead of standard round openings increased the proportional operating range of the valve by approximately 40%. The obtained simulation results were verified experimentally on a test bench.

The article presents an analysis of flow through a differential switching valve installed inside a throttle-check valve block. The valve is mounted in a sandwich type arrangement together with a control valve according to ISO 4401 standard. This type of block arrangement is popular and commonly used in hydraulic drive systems. The development of a typical throttle-check valve using a differential switching valve makes it possible to add a secondary fluid stream and thus increase the inflow rate to an actuator, which is particularly important in fixed-delivery pump systems. Due to the limited range of valve dimensions and the need to adapt flow paths to connection ports, channels of complex geometry are made inside the valve block. Therefore, the main aim of the work was to properly profile geometry of the differential switching valve spool in order to obtain a smooth opening in the entire displacement range. A 3D model of flow paths was built and CFD analysis was carried out. The obtained results of numerical simulations have been confirmed experimentally on a test bench. The CFD analysis allowed values of velocity and pressure profiles as well as axial flow force acting on the spool to be determined. The proposed new shapes of the spool head geometry significantly increase the spool head operating range. Although flow rate in the initial phase of switching valve opening was reduced, the amplitude of fluid flow fluctuations also decreased.

The main aim of this work was to create a model and carry out simulation tests of a hydraulic system for generating a pressure pulse with strictly defined time parameters. Obtaining a proper pressure course is a key condition for correctness of a long-term testing of hydraulic components durability, including e.g. new types of hoses. The requirements regarding the shape of the impulse were formulated on the basis of the ISO 6803:2008 standard which concerns hydraulic pressure testing of rubber hoses and hose assemblies without flexing. In the first step, a mathematical model of the system was built using equations describing the system geometry, flow equations and flow balances formulated for the separated volumes. Next, a simulation model of the hydraulic system was created in Matlab-Simulink. After obtaining flow characteristics, a model of a required pressure signal generator was built, followed by a fuzzy logic controller created in the Anfis editor of the Fuzzy Logic Toolbox. During the iterative tuning process, parameters of the fuzzy controller were adjusted. Then, the curves of the obtained and the required pressure for different values of the flow rate of the working medium were compared. As arises from the comparison results, the fuzzy logic controller fulfills the requirements and thus may be an advantageous option for generating the pressure signal.

The main subject of this article is pressure compensation in a multi-section proportional directional control valve. The undertaken compensation task was carried out without the use of neither additional compensating valves nor other correcting elements, such as sensors in a feedback control system. The proposed method consists in the appropriate adjustment of forces acting on the valve spool. It requires knowledge of the electromagnet force characteristics and the appropriately matched stiffness and initial tension of the valve spring. In order to achieve the assumed objective, a number of CFD simulations was performed on a 3-D fluid model. The CFD analysis allowed determination of the values of flow resistance through the valve and the axial component of the flow force acting on the spool. The values calculated for various spool positions and flow velocities were approximated using analytical equations. Next, the mathematical model was built and simulations in Matlab/Simulink system were carried out. In the first stage of the research, flow characteristics of a single valve section were determined. The obtained results were then verified on the test bench. In the second stage, the simulation model was used to examine the possibility of pressure compensation in a three-section control valve. In this case, the individual valve sections were loaded unevenly by applying pressure in a wide range of values. It has been demonstrated, that the appropriate shaping of the spool geometry allows usage of the flow forces for pressure compensation in multi-section proportional directional control valves.

This article presents a new control method for a pneumatic cushion for transporting heavy payloads. Pneumatic cushions are particularly useful for moving structural or non-structural components over hard, smooth floors. They can be put directly under load, lifted to a small height by applying air pressure and moved. A thin, friction-reducing air film is formed under the cushion during lifting. Currently, pressure is usually controlled manually, which causes difficulty in establishing an appropriate pressure value, especially when the load is distributed unevenly between multiple cushions. In practice, the pressure is often set higher than is necessary to move the load. Excessive pressure does not reduce friction, but increases air consumption. Hence, in this article an effort is described to obtain the minimum allowable pressure. The first part of the article includes the theoretical background, detailed models of the proposed automatic controllers and the parameters of a test bench. Experiments were carried out with a typical manual control system and two automatic controllers, with PID and fuzzy logic algorithms. The results indicate that automation of the control system significantly reduces air consumption and shortens the time needed to obtain the correct pressure. Moreover, it improves the stability of the load by allowing more accurate vertical positioning of individual cushions.

The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.

The main purpose of the work which was carried out and is presented in this paper was to examine the possibility of using fuzzy logic inference for conducting a risk analysis with the help of a sheet-based Failure Mode and Effects Analysis method (FMEA). At the beginning, the main features of the analysed method were presented, with particular emphasis put on the Risk, Priority and Number parameters. Then, a proposal has been made which suggests using Matlab Fuzzy Logic Toolbox package in order to convert the factors into the form of fuzzy sets and to define rules for fuzzy inference process has been made. Finally, the created fuzzy logic model was used to present an example analysis of a turbocharger failure in the fuzzified form.

This paper presents an analysis of potential failures of hydraulic components on the example of a hydraulic gear pump with the use of instruments of quality management. The “five why” method was implemented to evaluate failures as well as the bases for the causes which have an influence on pumps failures. The causes are connected with operation condition of gear pumps and the quality of working fluid. In the next step, by using a systematic diagram, appropriate improvement actions for the identified causes were determined.