Hydraulic Power Research Articles

Experimental Study of Sound Pressure Level in Hydraulic Power Unit with External Gear Pump

The article presents the results of an experimental study of the sound pressure level (SPL) caused by a hydraulic power unit with an external gear pump. The study was carried out with a specially developed laboratory experimental setup based on a common architecture used in hydraulic power units. Both the hydraulic system and the measuring equipment used are described in detail. The design of the experimental studies performed, including two main configurations with specific parameters regarding the operating modes of the system, is presented. The experimental results obtained are presented in the form of magnitude frequency responses which are compared in accordance with the experiment design. An analysis of the results obtained is performed using various quantitative indicators. For specific operating modes, parametric models were derived by approximation of the experimental data. The resulting models can serve in future work to reduce the SPL by passive or active means (e.g., frequency control of the electric motor). The quantitative analysis can serve as a basis of comparison with results obtained after adding passive (damping ring, etc.) or active means to reduce the SPL.

Fuel consumption of a wheel loader with power reflux hydraulic transmission system

The world is facing a limited supply of fossil fuel resources and stringent environmental constraints. Therefore, it is very important to develop advanced technologies to improve vehicle fuel economy, especially for construction vehicles, which have large engine displacements and poor emission characteristics. The majority of these vehicles use hydraulic mechanical transmission in the power train in order to improve maneuverability. However, a key issue on the hydraulic mechanical transmission is the low-efficiency torque converter. Focusing on this issue, we proposed the power reflux hydraulic transmission system (PRHTS), which is a new continuously variable transmission system. The PRHTS can improve the overall transmission efficiency of the power train by splitting the engine power into mechanical and hydraulic power. Therefore, the PRHTS is a valid solution to reduce the fuel consumption and subsequently decrease emissions from construction vehicles. In order to quantitatively study the effect of using the PRHTS on improving the fuel economy for construction vehicles, a wheel loader coupled with the PRHTS is modeled, and numerical simulation is conducted under the wheel loader driving condition. The simulation results show that the total fuel consumption of the wheel loader coupled with PRHTS is reduced by 3.39 % compared with that of the original wheel loader.

From concessions to competition: A journey through the evolution of the Philippine electric grid system, 1892–2021

This article traces the development of energy generation in the Philippines, tracing its origins back to 1892 and spanning through the significant reforms ushered in by the Electric Power Industry Reform Act (EPIRA) in 2001, and the subsequent two decades. The early chapters of this history witnessed the establishment of pivotal companies like Compania La Electricista and Manila Railway & Light Company (Meralco), which hinged on foreign investment and expertise. Meralco’s expansion encompassed the establishment of diverse power plants, including hydroelectric facilities, to cater to the escalating electricity demand. However, concerns surrounding foreign dominance and reliance on imported resources led to the creation of the National Power Corporation (NPC) in 1936 tasked with harnessing hydraulic power and increasing state participation in the energy sector. The post-war era witnessed the NPC’s significant role in bolstering the nation’s growing economy, especially through its expansive power development program and the nationalization of the electric power landscape. Despite progress in rural electrification, the NPC encountered challenges like financial constraints, political complexities, and the contentious Bataan Nuclear Power Plant project, which impeded its operational efficiency. The 1990 s unveiled a severe power crisis due to financial constraints and inadequate infrastructure. In response, the government sought to invigorate the sector by incorporating private sector engagement through independent power producers. To rectify inefficiencies and stimulate competition, the EPIRA was enacted in 2001 to steer the energy sector toward a comprehensive overhaul by restructuring the power industry and divesting NPC’s generation and transmission assets. This article provides insights into the historical trajectory of the Philippine energy sector, culminating in a series of reforms aimed at cultivating a more streamlined and competitive power sector, positioned to meet the nation’s ever-evolving energy needs.

A Study on Modeling and Experiment of a Wave Energy Converter Using Mechanical Coupled with Hydraulic Power Take-off

A Study on Modeling and Experiment of a Wave Energy Converter Using Mechanical Coupled with Hydraulic Power Take-off

On the Efficiency of Mobile Hydraulic Power Packs Operating with New and Aged Eco-Friendly Fluids

With the increasing environmental awareness, in many applications, ranging from agriculture to industry and logistics, a wider and wider use of eco-friendly fluids is desirable. Although the chemical and biological aspects related to environmental compatibility have been extensively investigated by industries and researchers for obvious environmental reasons, not much literature is available on the performance of hydraulic components and systems operating with eco-friendly fluids, especially on the possible degradation of performance due to fluid aging. This work is aimed at studying the influence of eco-friendly fluids on the performance of external gear pumps for compact mobile hydraulic power units, which are among the most widespread hydraulic devices in the world, for their cost-effective and flexible construction. Once the experimental set-up is implemented to be well representative of the hydraulic power packs’ typical arrangement, pump performance is investigated. Pump energy performance is obtained in terms of volumetric efficiency and torque efficiency. Alongside the traditional fluid, two types of eco-friendly fluid available in the market are tested. Once the comparison is complete, the investigations are devoted to highlighting the impact of fluid aging on the pump performance. The fluids were aged through 2000 h operation under heavy-duty thermo-mechanical stress on a separate set-up and, afterwards, the pump performance was tested again with aged fluids. The results allow the assessment of the influence of different fluids on pump performance and a comparison of the impact of new versus aged eco-friendly fluids. The eco-friendly fluids exert a significant effect on the pump energy profile. The pump overall efficiency increases, marking an up to 5% improvement, depending on the cases. Fluid aging is found to reduce the pump’s overall performance. This paper addresses the key points defining the pump performance and provides new information on the topic. The results are original and represent a fundamental contribution to define the best practices for energy and maintenance management of hydraulic systems and to foster the deployment of further studies on models and simulation tools to catch the effect of the fluid condition.

Perancangan Automatic Sprinkler System Pada Gudang Batu Bara Perusahaan Produksi Susu

Fire is a condition that occurs due to the oxidation of three elements (fuel, oxygen and heat) which can cause property losses, injury to death. One of the places that is prone to fire is a coal storage warehouse, considering the characteristics of the materials stored in it. In order to reduce losses due to fires, an automatic sprinkler system is needed in the coal warehouse of a dairy production company to help extinguish the fire as soon as possible when a fire occurs. Based on these problems, this research will determine the number of sprinklers needed as an automatic extinguishing system as well as the volume of water, pump power, and groundwater tanks. This type of research is quantitative research by direct observation of the object under study, then the researcher measures the coal warehouse space using a building meter. From the results of calculations by taking a sample of the coal warehouse room of a dairy production company, the required number of sprinklers is 111, the required water volume is 399.6 ????3, the required pump power and ground water tank are, pump hydraulic power (HHP) 1.2910128 kW, pump shaft power (BHP) 1.7213504 kW, pump electric power (P) 3 kW, diesel pump (PpD) 2 HP, jocky pump (PJk) 0.3 kW, GWT capacity (QGWT) 17 m3.

Design Optimization of Electrical Structure Parameters of Induction Asynchronous Mechanical–Electric–Hydraulic Power Coupler

In response to the problems of considerable size, loose structure, and low energy conversion efficiency of multi-energy power coupling devices, this paper makes improvements based on the mechanical–electric–hydraulic power coupler proposed by our research group. We propose a new asynchronous mechanical–electric–hydraulic power coupler (IA-MEHPC). This mechanism integrates a traditional three-phase asynchronous motor with a swashplate axial piston pump/motor to realize the mutual conversion of electrical, mechanical, and hydraulic energy. Compactness, efficiency, and adaptability are the distinguishing features of the complex. This paper builds a three-dimensional model of the IA-MEHPC and a two-dimensional theoretical model of the electrical structure (motor part). Moreover, the electrical structure parameters of the IA-MEHPC are optimized using an approximate response surface-based optimization method. The maximum motor peak torque and minimum torque fluctuation are identified as optimization objectives, and we obtain the optimal combination of parameters. The simulation results show that, compared to the pre-optimized structure, the peak motor torque of the optimized IA-MEHPC is increased by 5.78%, and the torque pulsation coefficient is reduced by 15.83%, in line with engineering practice expectations. This paper innovatively proposes and optimizes IA-MEHPC, which is significant for developing hybrid mechanical devices and subsequent research.

Electrohydraulic Power Switching Control for Mechatronics–Electrohydraulic Power Coupling Electric Vehicles Considering Optimal Speed Thresholds

Switching between different working modes customarily brings sudden changes in torque and speed, leading to energy wastage for mechatronics‐electro‐hydraulic power coupling electric vehicles. Investigating the effect of vehicle speed thresholds on operating mode switching when working in concert with compound energy sources is timely. Thus, under the constraint of a known reference path, the optimal threshold is determined by weighing the path tracking accuracy and economic performance with the vehicle speed and the accumulator pressure as control variables. Wherein the constraint relationship between the factors is fully elucidated by combining various typical and actual road conditions. The validation results indicate a positive correlation between the starting acceleration capacity and the threshold value for a certain accumulator volume. The optimal speed thresholds under new European driving cycle, China light‐duty vehicle test cycle‐passenger, and actual routes are 4.1, 3.81, and 3.66 m s−1, with state of charge consumption rates of 6.30%, 8.56%, and 4.25%, respectively. More frequent speed switching may lead to excessive hydraulic power wastage, thereby increasing dependence on electrical power. Appropriate threshold setting can effectively enhance path tracking accuracy and hydraulic utilization under unpredictable road conditions. This research may in the future provide theoretical support for the rational control and interconstraint mechanism of energy utilization in hybrid vehicles.

Design methodology for an integrated axial piston-type electrohydraulic unit

This paper proposes a design methodology for power-dense and high-efficient electrohydraulic units (EHUs) that can be used to select design specifications for the electric machine (EM) for a given hydraulic machine (HM) architecture. The proposed method evaluates EHU performance considering both electric and hydraulic power losses. The compactness of the EHU is achieved by integrating an axial piston unit as HM inside a permanent magnet EM. The paper provides a sensitivity analysis for important EHU design specifications and discusses the best choices for reducing total mass and energy loss. The study finds that greater aspect ratios promote power-to-weight ratio, while high voltage promotes energy efficiency. The paper also discusses the choice of fixed versus variable displacement HMs, with the finding that a variable displacement unit helps address low efficiency limits of low-speed operation, particularly for low voltage electric machines. Additionally, variable displacement can also be used to reduce EM losses when meeting a flow-pressure demand. The proposed methodology has applications in fields such as off-road vehicles.

Stability of mass oscillations in hydropower plants with brook intakes

The need for more energy storage in the transition to a renewable energy system leads to increasing interest in upgrading existing hydropower plants to pumped storage plants. Such upgrades result in stronger hydraulic transients in the tunnel system, including increased mass oscillation amplitudes. In this study, a generalized tunnel system with multiple brook intakes/surge tanks is analysed to assess the influence of the brook intakes on the mass oscillation stability. The variables that are assessed are the number of brook intakes, cross section area, the amount of inflow, and throttling of the brook intakes/surge tanks. The study is carried out using frequency-response analysis, where the excitation is the oscillation of the guide vane position, and the response is the product of the measured head and discharge (equivalent to the hydraulic power). The results show that brook intakes are generally beneficial for the stability of the mass oscillations. Existing hydropower plants with brook intakes may have sufficient stability margins to allow upgrade and reconstruction without the need for upgrading of the surge tank with regard to mass oscillation stability.

An Efficient and Effective WEC Power Take-Off System

A numerical model for a hydraulic wave energy converter power take-off is developed in this study. The system architecture is described and the mathematical model for each component is presented. The accumulators are not used as energy storage devices. Instead, they are used to reduce the stiffness of the system, increase the response time, and improve the controllability. The numerical model was implemented using MATLAB/Simulink. The design variables selected for this study are the maximum displacement in the hydraulic motors, and the shaft inertia. The effect of these design variables on system performance is studied using latin-hypercube sampling to generate the cases to be simulated. The displacement in the hydraulic devices is used as a control input to adjust the pressure in the hydraulic cylinder and then change the force acting on the floating body. The desired force is calculated by a high level controller that estimates the force value to achieve impedance matching in the WEC. The torque in the electric generator is used to control the shaft speed. The system was designed to actively use reactive power flow to maximize the electric power output in the generator. The model developed in this study is a complete wave-to-wire model based on a co-design approach that considers the effect of all the different subsystems on the dynamic behavior of the whole WEC system. Twelve different wave conditions were tested. The most critical metric for this study is the electric power in the generator, which is the objective function of the optimization that was performed for all the wave conditions defined as case study. The wave-to-wire efficiency, which includes the complete wave energy to electrical energy conversion chain, is also calculated in this work.

Stress-Strain Analysis of Turbine Blocks with Steel-Lined Reinforced Concrete Spiral Case of High-Head Hydraulic Power Plants

Stress-Strain Analysis of Turbine Blocks with Steel-Lined Reinforced Concrete Spiral Case of High-Head Hydraulic Power Plants

Analyzing the possibility of using hiqhtorque hydraulic motors for rotation of the drums of automatic concrete mixers

Goal. The goal is conducting an analysis of the use of hydraulic fluid power for rotating the drums of concrete mixers, in particular, evaluating the possibility of using high-torque low-speed radial-piston hydraulic motors instead of axial-piston motors with planetary gearboxes. The technical level of such hydraulic drives is assessed based on the use of mass to torque and power ratios. The nomenclature, technical characteristics and design features of high-torque hydraulic motors are considered. In particular, compared to previous studies, the nomenclature of the considered hydraulic motors is widespread. Method. The methods of comparative analysis of designs and technical characteristics of axial-piston with planetary gearboxes and high-torque hydraulic motors according to the main technical parameters, in particular, the developing pressure, torque, rotation frequency and power depending on the specific indicators of the mass ratio to the absolute values of these parameters were used. Design features of high-torque hydraulic motors were also considered. Originality. For the first time in the domestic literature, a comparative analysis of the performed high -motion hydraulic motors of the MCR model was carried out. Results and practical usefulness. It is recognized that the modern technical level of high-torque hydraulic motors allows to compete with axial-piston gear hydraulic drives for rotating drums with a concrete mixture of auto-concrete mixers. The given materials will be useful in the educational process for machine-building specialists who study hydraulic fluid power as a means of improving the technical level of various machines and mechanisms.

Application of electric traction drive for the modernization of locomotives with hydraulic power transmission

The issue of updating the locomotive fleet of industrial enterprises by modernizing outdated diesel locomotives with hydraulic power transmission was considered. The analysis of existing modernizations shows the possibility of using traction electric drive while preserving the original group drive of wheel pairs. This approach is used by manufacturers when updating outdated and creating new diesel locomotives and traction modules for rolling stock. A possible option is the use of single-motor carts. Previous studies on the choice of the type of wheel pairs drive were analyzed and it was established that the use of a group drive of wheel pairs provides the possibility of realizing high traction forces without additional devices, and the drive itself has a lower cost. This determines the expediency of using a group drive of wheel pairs when modernizing diesel locomotives with hydraulic power transmission. To realize these advantages, it is necessary to use a traction electric drive based on electromechanical alternating current converters. This approach was implemented by Mykolaiv Locomotive Repair Plant LLC during the modernization of TGM6 diesel locomotives. The diesel locomotive is intended for shunting and hauling operations, as a result of which it was assumed during the design that the traction force when moving is equal to 320 kN, the continuous traction force is 300 kN, and the maximum speed is 50 km/h. The power plant consists of a modern Cummins diesel engine and a synchronous generator. A frequency-controlled asynchronous traction electric motor is used to drive the wheel pairs. Power and control of the electric motor is carried out using a voltage inverter. Diesel locomotives use a controlled electric drive of cooling motor-fans, and semiconductor converters are used to power auxiliary systems. The locomotive and its systems are controlled by a microprocessor control system. The application of the traction electric drive based on the asynchronous electric motor provided the estimated efficiency of the diesel locomotive and the efficiency of the diesel power at the nominal power and the estimated speed of the long-term mode, equal to 6 km/h, are 0.312 relative units and 0.69 relative units, respectively. The analysis of ways to improve the traction electric drive to reduce the consumption of fuel and energy resources was carried out. It was determined that the use of a power plant with energy storage and the use of two traction electric motors for the group drive of wheel pairs may be expedient

Study of the Transformation of Water Flow Rate and Depth in the Diversion Canal of a Hydraulic Power Plant with Daily Runoff Control

Study of the Transformation of Water Flow Rate and Depth in the Diversion Canal of a Hydraulic Power Plant with Daily Runoff Control

Optimisation of Control Strategies for Power Shift Gearboxes

This study is based on the influence of power shift control on the smoothness of cotton picker shifts and proposes an optimization method for the smoothness of power shifts with different control strategies for the gearbox. Through the structural design of the power shift mechanism control module, the hydraulic power distribution of the hydraulic system of the hydraulic travel module and its control mode are analyzed, and a regional cooperative shift control strategy is proposed in conjunction with control theory. A model of cotton picker dynamics was built using AMESim simulation software. In addition, the traditional control strategy was simulated and compared with the Statement component automatic control strategy to analyze and discuss the control deficiencies in power shift smoothness. Then, a particle swarm genetic algorithm (PSGA) was constructed by integrating the PSO algorithm and the genetic algorithm to verify the effectiveness of the algorithm in improving the dynamic performance and shift smoothness of the gearbox. The algorithm was verified using bench tests, and the algorithm improved the harvesting quality and efficiency of the cotton picker.

Analysis of the Thermal–Mechanical–Hydraulic Coordination Mechanism of a Constrained Piston Hydraulic Engine

By effectively integrating traditional engines with reciprocating plunger pumps, the constrained piston hydraulic engine can simultaneously output hydraulic energy and rotational mechanical energy, which effectively solves the problems of the complex structure, long power transmission chain, and low energy conversion efficiency of traditional power sources. Based on a certain single-cylinder diesel engine, a single-cylinder axial constrained piston hydraulic engine was designed, and its thermal–mechanical–liquid coordination mechanism was studied and analyzed in-depth. A mathematical model of the thermal–mechanical–liquid coupling working process of the single-cylinder axial hydraulic engine was established, and the conversion mechanism and output of the three types of energy, thermal, mechanical, and liquid, were simulated and analyzed. The results show that under the premise of improving the overall efficiency, the constrained piston hydraulic engine can effectively output mechanical–hydraulic dual-element power, and its combustion characteristics and output power performance indicators meet the expected design requirements. The maximum amplitude difference of the output hydraulic oil flow rate reaches 248 L/min, and the flow rate fluctuates greatly, so it is necessary to adopt methods to suppress the flow rate pulsation to ensure the reliability of the output flow rate.

ANALYSIS OF TECHNICAL CHARACTERISTICS OF HIGH TORQUE HYDROMOTORS WITH LIMITATIONS BASED ON DYNAMIC CALCULATIONS

The goal is to study the technical characteristics of the world's largest modern high-torque multi-acting hydraulic motor from the point of view of ensuring reliable operation by the manufacturer at elevated pressures, speeds and depending on the type of working fluid used. Analysis of the influence of dynamic loads on fluctuations in pressure and speed of the hydraulic motor in the modes of starting and braking, taking into account changes in the pump flow rate and inertial loads. Method. Dynamic calculation of a hydraulic fluid power with a high-torque hydraulic motor based on studies of external loads, changes in the pump feed time, providing the maximum speed. To solve nonlinear differential equations when calculating the pressure in the hydraulic drive and the rotational speed of the hydraulic motor, the VisSim application software package was used. The modes of change in the operation of the hydraulic motor over time in terms of rotational speed, pressure in the hydraulic fluid power, output power and hydromechanical efficiency, depending on the external load and pump flow, are presented on the corresponding oscillograms. The mathematical model of the hydraulic fluid power includes simulation modules for controlling the supply of an axial piston pump and changing the moment of resistance on the hydraulic motor. Results. Calculations of the dynamics of a hydraulic fluid power with a high-torque multi-acting radial piston hydraulic motor showed the need for preliminary modeling of its operation modes, taking into account the nature of the external loading, the moment of inertia and the intensity of the pump flow. Conclusion. The conducted studies can be used in the development of hydraulic fluid power with high-torque hydraulic motors to clarify the technological processes of work during the operation of a hydraulic machine.

Hydraulic Power System Control using State Feedback Controller (SFC)

In an electrical network, generators work and provide power to the loads. When the load on the generator increases, the speed of the generator decreases then resulting in a reduction in the frequency of the network. This paper was designed within the state feedback controller (SFC) to improve the hydraulic power system performance. The performance of the proposed controller is compared with simple feedback controller (FC) in the simulation environment. The load variation was tested which is 5%, 10%, and 20% variation. The testing results show that in terms of steady state error (SSE) and overshoot, the SFC is superior. In terms of settling time, the FC method is faster. Since it quickly reaches steady event not getting into set-point. The overall, it can be concluded that SFC can give better performance than FC in the frequency control of a hydraulic power system.

Anomaly Detection for Hydraulic Power Units—A Case Study

This article aims to present the real-world implementation of an anomaly detection system of a hydraulic power unit. Implementation involved the Internet of Things approach. A detailed description of the system architecture is provided. The complete path from sensors through PLC and the edge computer to the cloud is presented. Some technical information about hydraulic power units is also given. This article involves the description of several model-at-scale deployment techniques. In addition, the approach to the synthesis of anomaly and novelty detection models was described. Anomaly detection of data acquired from the hydraulic power unit was carried out using two approaches, statistical and black-box, involving the One Class SVM model. The costs of cloud resources and services that were generated in the project are presented. Since the article describes a commercial implementation, the results have been presented as far as the formal and business conditions allow.