Hydraulic Accumulator Research Articles

A rapid compression large-volume press with a high pressure jump above 10GPa within milliseconds.

A high pressure jump through a rapid compression within milliseconds (ms) provides an important approach for searching novel matters and investigating their physical and chemical properties. Herein, we report a unique rapid-compression large volume press with a high pressure jump above 10GPa within 20ms by introducing a Walker-type module and hydraulic accumulators. The sample pressure can be rapidly increased from 1-5GPa to 12-16GPa by different modest compression rates varying from 10-2 to 633.5 GPa/s. The rapid pressure jump on the specimen has been successfully verified through the observed rapid phase transition of ZnTe from semiconductor to metal transitions, as evidenced by the variation in its electrical conductivity. The highest pressure jump of 10.2GPa within a rise time of 16.1ms is achieved, which is significantly higher than previous results (5.8GPa within 20ms) using a Bridgman-type anvils in such an apparatus. We found that rapid compression significantly enhances the phase transformation of C70 fullerene from a disordered graphite to an amorphous phase compared to static high-pressure experiments. The high pressure jump technique developed in this study will thus have great applications in materials science, physics, chemistry, and earth science.

Определение диссипативных потерь в гидравлическом приводе газораспределительного механизма двигателя внутреннего сгорания

Controlling the opening and closing times of intake and exhaust valves can improve the efficient parameters of an internal combustion engine and reduce the toxicity of combustion products. The valves are moved by an electronically controlled hydraulic drive. The energy consumption for the operation of a hydraulic valve drive is greater than when using a traditional mechanical drive. The dissipative energy losses in the accumulator one-way hydraulic valve drive are investigated. The working fluid of the hydraulic drive is SAE 5W-30 motor oil. The oil pressure behind the pump is 8 MPa, the diameter of the hydraulic cylinder is 16 mm. The main items of energy consumption are identified, and a methodology for their determination is proposed. The assessment of the efficiency of the hydraulic drive was based on the law of conservation of energy. To determine energy costs, a hydraulic drive model was compiled in the Simulink environment. A law of valve movement similar in shape to trapezoidal was obtained. The maximum speed of valve movement during the opening process is 4 m/s, during the closing process 3.8 m/s. During the period when the valve is held near the maximum lift of 14 mm, free oscillations with an amplitude of about 1 mm are observed. The energy consumption for a single actuation of the valve, which has a progressively moving mass of 0.5 kg, amounted to 25.9 J. Of this, a little more than 70% is spent on filling the hydraulic cylinder with liquid, the rest is spent when emptying it. As a result of throttling the fluid flow in the hydraulic cylinder rod stroke limiter and hydraulic brake, 56% of the energy is lost. Large energy losses are observed between the hydraulic accumulators and the hydraulic cylinder. When the cylinder is filled, 21.1% is lost here, and when it is emptied, 10.4%. Increasing the capacity of the supply and drain lines between hydraulic accumulators and hydraulic cylinders allows you to increase the speed of opening and closing valves. The main ways to increase the energy efficiency of the drive are to shift the hydraulic accumulators to the hydraulic cylinder, increase the diameter of the connecting lines, and increase the throughput of the solenoid valves.

Development of a Hydraulic Damping Device to Protect a Centrifugal Pump

This study focuses on the utilization of hydraulic accumulators to mitigate hydraulic shock. The pressure energy within the system is converted into compressed gas energy in the accumulator. This continuous conversion between the two forms of energy allows for the absorption of hydraulic shock force, thereby ensuring system stability. The study involved the creation of experimental circuits, which were tested both with and without the inclusion of a hydraulic accumulator. The results confirmed that the accumulator has a substantial impact on reducing hydraulic shock phenomena. The study's findings demonstrate that the shocks in the hydraulic system can be efficiently managed by selecting an appropriate inflation pressure for the accumulator and utilizing various connection line data.

Ways to Protect Equipment from Hydraulic Shock

The hydraulic equipment is experiencing damage to its components and even the mechanical equipment owing to hydraulic shock induced by a sudden rise in load, resulting in a step reaction in the hydraulic system. An analysis of the hydraulic system is conducted to protect the equipment from the detrimental effects of hydraulic shock. This analysis includes examining components such as the hydraulic damper, centrifugal pump, accumulator, control valve, and others. The primary function of the power component is to mitigate hydraulic stress by altering the pump’s flow rate. The control element initiates the reversing of the valve in the hydraulic system in order to mitigate hydraulic shock. The auxiliary components primarily concentrate on enhancing the efficiency of the accumulator and maximizing the synergistic utilization of damping components. By adjusting the input value, one may regulate the flow rate and pressure of the system. The discussion revolves around finding the most efficient frequency in the shortest amount of time.

Predictive model using artificial neural network to design phase change material-based ocean thermal energy harvesting systems for powering uncrewed underwater vehicles

Uncrewed underwater vehicles (UUVs) significantly benefit from phase change material (PCM)-based ocean thermal energy harvesting for long mission duration. However, this technology relies on different parameters that are critical to its efficiency. Sea trials indicated that a design using this technology has lower performance than its initial specifications. This underperformance results from different factors—mainly, the UUV's trajectory, travel time, temperature fluctuations, and biofouling on the heat exchanger due to long-term underwater operations. Therefore, there exists a need to continuously monitor the ambient energy harvesting system and predict system performance for mission planning. Two major parameters that influence the energy harvesting system include the pressure inside the hydraulic accumulator and the electrical load. This work focuses on the hydraulic-to-electric energy conversion system. A combination of numerical simulation and experimental tests is used to develop a predictive model using artificial neural network (ANN) in MATLAB. 1000 data samples from a numerical model are used to train the ANN. Compared to experimental results, the ANN model predicts the designed benchtop system's total efficiency with a maximum efficiency of 51 % and an overall relative error of less than 15 %. This work will enable energy-efficient mission planning for UUVs using PCM-based ocean thermal energy harvesting.

Modeling and Analysis of Inertial-Hydraulic Power take-off Device

This paper introduces a novel power output device that combines inertia and hydraulics, which captures vibrations caused by external forces acting on the carrier in space using the sensitive gyroscope of the inertia system. The captured random mechanical energy is then converted into hydraulic energy, rectified and regulated by the hydraulic system, and transformed into stable output energy. The influence of gyroscope angular momentum on the energy capturing capability is investigated through the development of a dynamic model. Additionally, a hydraulic power output system is designed, and the effect of hydraulic accumulator parameters on energy absorption fluctuations is analyzed. This research offers valuable insights for the design and optimization of the device.

Design and simulation of an off-grid marine current-powered seawater desalination and hydrogen production system

The use of marine current energy to provide a stable supply of energy and fresh water to islands and remote areas is a promising prospect. In this study, an integrated marine current-powered seawater desalination and hydrogen production system was proposed. For higher integration and efficiency, the generator and seawater pump were integrated into the nacelle and mechanically connected to the main shaft. Four operating modes and the corresponding start-stop and maximum power point tracking (MPPT) control strategy were designed to achieve energy distribution between the two loads. Considering the frequent start-stop caused by the sinusoidal characteristic of marine current energy, a soft start-up process was designed for the RO elements, including dual hydraulic accumulators and a smooth transition process to avoid abrupt changes in feed pressure and feed flow rate. Finally, the performance was obtained by simulation. During the 6 h of the ebb tide, the desalination system produced a total of 841.77 L of fresh water, while the electrolyzer produced 1038.5 SL of hydrogen and consumed 0.95 L of water. The average power coefficient of the turbine was 0.434, and the specific energy consumption of the desalination system was 2.03 kWh/m3, indicating good MPPT performance and high efficiency.

Information System for the Selection of Hydropneumatic Capacitive Vessels

This article describes an algorithm for the automatic selection of hydropneumatic capacitive vessels used for household and industrial purposes. The suggested informational system makes it possible to reduce the working time spent on the selection of equipment and increase the relevance of the analyzed information. The article discusses a detailed description of the design of pneumohydroaccumulators, as well as provides examples of calculations of their main characteristics. The main task we needed to solve was a multi-criteria choice, and the article provides an overview of methods for solving this problem. In addition to these methods, we analyzed information systems that allow one to select suitable equipment among various alternatives. Based on the analysis of methods and similar software solutions, the authors suggested an information system and an algorithm for automatic selection of hydraulic accumulators by searching for options that meet the parameters specified by the system user. Also, the article discusses the process of purchasing capacitive equipment. There was demonstrated a logical model of the database structure storing the technical characteristics of the equipment which reflects objects of the information system and their connections. In this article we presented and argued the software for development of a specified information system. The development of the information system was based on the "1С platform: The enterprise". The task of selecting hydropneumatic capacitive vessels was solved by a request that can be interacted with through a report in the information system. This report allows the user to search for equipment by quantitative and qualitative characteristics: volume, operating pressure, vessel material, flange material, installation type (vertical or horizontal), availability of legs, cost, manufacturer or supplier. The report options allow users to search for equipment both in accordance with the specified parameters and with a deviation from them but only if the parameter is quantitative. The results of the report are ordered by relevance to the criteria specified by the user. The operation of the report query aggregating data was reflected in the flowchart. The article presents a situation where the user solves the selection problem by using capabilities of the report. The problem of multi-criteria selection was formulated in a way to demonstrate how a clear parameter of the report becomes fuzzy, and our solution of it allows you to find more alternative options with sorting by relevance helping you to identify the most suitable pneumohydroaccumulator. This software package was registered in the state registry of computer programs.

Comparison of hydraulic, pneumatic and electric linear actuation systems

Different applications or industries use different systems for linear actuation, such as hydraulic, pneumatic or electric. Electric systems are becoming increasingly popular and are already replacing hydraulic systems in various applications. These are known to be potentially harmful to the environment, as large amounts of fluid can be released into the environment in the event of a pipe burst or other accident. This paper presents the results of a comparison between hydraulic, pneumatic and electric systems under variable conditions but with similar loads in all three systems. The common feature of all three systems is the input power, which was limited to 1.1 kW. There was no hydraulic accumulator in the hydraulic system and no pressure vessel in the pneumatic system, so no stored energy could influence the system behaviour or results. The main difference between the systems studied was the profile of displacement and power consumption. The most consistent response and lowest power consumption were obtained with the electric system, although both hydraulic and pneumatic systems can achieve consistent response with some modifications.

Rubble Sandstone Unloading and Screening Unit with Non-Volatile Auxiliary Equipment Drive

For the road industry, it is quite important to reduce costs and energy consumption, as well as energy recovery in process plants. To solve this problem at one of the stages of the industrial process, which is production of road metal, an important material for road construction, it is proposed to develop autonomous power unit based on recuperation of the kinetic energy of dump trucks, namely a unloading and screening unit of crushing and screening plant with non-volatile drive of auxiliary equipment.A non-volatile unloading and screening unit separates the feedstock at the primary stage of production in a non-volatile operating mode, using recovery of the kinetic energy of trucks been unloaded. After loading rubble sandstone into the receiving hopper, the unit activates the process of material segregation into coarse and fine fractions. The respective fractions are fed to the appropriate feeders for subsequent technological processing. The advantage of the unit is the autonomy of the vibrator and feeders’ drives, which helps to raise the efficiency of the process of unloading and separation of the rubble sandstone and reduce energy costs for production of the finished product.The evaluation of the functional capabilities of the non-volatile hydraulic drive of the unloading and screening unit was carried out for hydraulic motors of the screening and conveying equipment. The apron feeder of KM PP-2–10–60B type providing a continuous and uniform supply of feedstock was assumed as the basic equipment, and the volume of working fluid in the hydraulic accumulator supplied by hydraulic jacks was calculated. The results showed that two hydraulic jacks with the specified parameters can provide the required flow and allowed determining the amount of energy stored in the accumulator during feedstock loading. The calculated power of the hydraulic motor allows its use in the feeder. The economic efficiency of the installation with an autonomous drive is estimated considering the mode of operation, the number of shifts and the tariff for electricity.

Research on Multistate Variable Prediction of a Master‐Slave Electric‐Hydraulic Hybrid Vehicle Based on CNN‐LSTM Model with Attention Mechanism

This paper utilizes a convolutional neural network and long short‐term memory with attention mechanism (CLA) prediction model for time series forecasting. An innovative master‐slave electric‐hydraulic hybrid vehicle (MSEHV) is introduced. It simplifies the drivetrain structure by utilizing planetary gears for energy transfer and coupling to transform electrical, mechanical, and hydraulic energy. This paper conducts simulation verification using existing control strategies. It combines the velocity time series information with the hydraulic accumulator pressure time series information to create a unified time series. Some of the more popular machine learning and neural network algorithms are considered, and the mean square error, mean absolute error, and coefficient of determination evaluation metrics are calculated for validation. The research presents a developed battery state of charge regression prediction model based on genetic algorithm‐backpropagation by combining the predicted results of composite time series with the current discharge depth of the battery. The validation results indicate that the CLA time series prediction model proposed in this paper for MSEHV has higher prediction accuracy compared to other prediction models.

Development of a Testing System for High-efficiency Power Recovery Bag Accumulators

Currently, most of the bladder-type accumulator test benches used have problems such as large installed capacity, severe energy loss, and incomplete testing functions. This article focuses on the research of the testing requirements and power recovery issues of bladder-type accumulators. A new type of hydraulic schematic and electrical control system for power recovery bladder type accumulator testing based on mechanical compensation with dual output shaft motor transmission, differential charging and discharging of dual accumulators, and parallel addition of oil replenishing accumulators has been designed. A measurement and control software based on the LabVIEW platform has been developed. The experimental results show that the system’s power recovery efficiency can reach 60.5% by adopting a scheme of mechanical compensation type power recovery, differential charging and discharging of energy accumulator group, and parallel addition of oil replenishing energy accumulator. The testing system can accurately, efficiently, and conveniently complete various performance tests of hydraulic bladder accumulators.

Sensitivity analysis of levelized cost of hydro-pneumatic electricity storage for grid support applications

The first sensitivity analysis of hydro-pneumatic levelized cost of electricity storage for a set of twelve power system applications, ranging from primary response to seasonal storage, is done, using as parameters the specific power and energy investment costs and round-trip efficiency. The electric-to-electric round-trip efficiency for hydro-pneumatic energy storage systems is discussed, using a lab-scale hydro-pneumatic energy storage system that was built using commercially available bladder hydraulic accumulators. In general, the results show that hydro-pneumatic energy storage can be very competitive whenever the number of annual cycles is sufficiently high, as happens in the case of primary response application but, even for applications with a low number of annual cycles, it can be competitive for applications with a high ratio power/capacity. A comparison with the dominant technologies, pumped hydro and Li-Ion, shows that, for the highest hydro-pneumatic energy storage investment costs considered, this technology will only be competitive for primary response, but, for the lowest investment costs considered, hydro-pneumatic energy storage is more cost-effective than Li-Ion for all applications, and can even be more cost-effective than pumped hydro in four of the twelve applications. The main challenges to the development of hydro-pneumatic energy storage systems are discussed.

Hardware-in-the-loop testing framework for active accumulator wave energy converters

The hardware-in-the-loop technique is a hybrid co-simulation approach that joins real physical and virtual components. The real components may be the power take-off while the virtual ones the numerical models of sea wave and wave energy converter hydrodynamics. This simulation approach has been published with some regularity, however a review of the state-of-the-art has not been found, in particular in the research field dedicated to wave energy converters. Thus, the objective of this paper is to provide the ongoing results of such review, such as the generic testing framework and taxonomy, and their articulation on the simulation of a new oil-hydraulic power take-off concept. In this new concept, different power take-off nominal pressures may be regulated according to different sea states, by changing the hydraulic accumulator charging characteristics. Therefore, this active accumulator is intended to allow an increase on the range of possible Power Take-Off damping forces, thus, better wave energy harvesting performance. The paper results are also intended to support novice and advanced researchers to design simulation approaches in a clear and appropriate manner.

Research on energy saving system of hydraulic excavator based on three-chamber accumulator

As the boom of a hydraulic excavator drops, the potential energy accumulated during the lifting process is converted into thermal energy and dissipated through the throttling action of the hydraulic valve, leading to excessive fuel consumption and serious energy waste. In order to address these issues, a hydraulic excavator energy saving system based on a three-chamber accumulator is proposed. Firstly, the conventional piston-type hydraulic accumulator is integrated with the hydraulic cylinder to form a three-chamber accumulator, which has a pressurizing function during energy storage. Then, a hydraulic excavator energy saving system based on three-chamber accumulator is proposed, which can store and reuse the energy loss from throttling and overflow of the hydraulic system without changing the hydraulic system of the excavator. The potential energy of the boom during drop is converted into hydraulic energy and stored in the three-chamber accumulator, which is then released to drive the boom lift, and the original system of the excavator does not work in both situations. The proposed boom speed control system ensures the operability of the excavator. The energy saving system was tested on a 21.5-ton hydraulic excavator, and the results showed that the energy consumption of the boom lifting hydraulic circuit was reduced by 47.99 %, and the engine fuel consumption was reduced by 11.42 %. This system can also be applied to other hydraulic equipment with frequent changes in potential energy of the working mechanism.

Hydraulic accumulators in energy efficient circuits

Hydraulic accumulators have long been used in hydraulic circuits. Applications vary from keeping the pressure within a circuit branch to saving load energy. Among these applications, storing and releasing energy has gained attention in recent years due to the need for efficient circuits. In this sense, accumulators are the hydraulic counterparts of batteries and capacitors in electrical circuits. From hydraulic hybrid vehicles to complex agricultural machinery, accumulators have been successfully implemented, and significant energetic gains have been reported. This article reviews typical applications where accumulators can be used to this end and discusses the challenges that still have to be overcome in each situation.

The Effect of Hydraulic Accumulator on the Performance of Hydraulic System

The purpose of this paper is to depict the effect of adding a hydraulic accumulator to a hydraulic system. The experimental work includes using measuring devices with interface to measure the pressure and the vibration of the system directly by computer so as to show the effect of accumulator graphically for real conditions, also the effects of hydraulic accumulator for different applicationshave been tested. A simulation analysis of the hydraulic control system using MATLAB.R2010b to study was made to study the stability of the system depending on the transfer function, to estimate the effect of adding the accumulator on stability of the system. A physical simulation test was made for the hydraulic system using MATLAB to show the effect of the accumulator when it's connected to the system for different parameters and compare it with a PID controller. The hydraulic system has been simulated and tested using Automation Studio (AS) to measure different data such as the linear speed of hydraulic cylinder and the effect of connecting the accumulator to the system. All the results showed that the hydraulic accumulator has a great benefits and a large enhancement to the hydraulic system.

Research on electro-hydraulic composite drive winch and energy recovery system for mobile crane

Owing to the high power consumption and limited control precision of traditional hydraulic drive winch systems, this study proposes hydraulic and electric-type energy recovery systems. The accumulator used in the hydraulic type has low energy density, which makes it difficult to store a large amount of energy. Meanwhile, the electric motor/generator used in the electric type cannot solve the secondary slip because of oil leakage, which leads to low controllability and high-power consumption under near-zero speed and high torque conditions. Thus, based on electric construction machinery with high-pressure, energy-dense electric energy storage units, this study proposes an electro-hydraulic composite drive winch and energy recovery system and control strategy for mobile cranes. Considering the good control characteristics of the electric motor/generator and the high-power density of the hydraulic accumulator, this hydroelectric composite drive and energy recovery system may solve the secondary sliding challenge and ensure large torque output at near-zero speed. A simulation model of the mobile crane is established to verify the feasibility of the proposed system and control strategy. The research results showed that the system is more efficient at recovering energy when the weight is lowered by a greater distance.

Hybrid drivetrain with dual energy regeneration and collaborative control of driving and lifting for construction machinery

The push for a more sustainable logistics industry has been driving heavy machinery manufacturers to develop electric construction machinery (ECM). To improve energy efficiency of ECM, we propose a multistage parallel hybrid drivetrain (MPHD) that combines a parallel hybrid lifting system (PHLS) with an electrohydraulic driving system. The proposed MPHD can recover both gravitational and braking energy through a network of hydraulic accumulators. To optimize power distribution of MPHD under various conditions, an energy management strategy with an adjustable degree of hybridization (DOH) is developed to collaboratively control lifting and driving systems. In addition, experiments and simulations are conducted to verify the feasibility and energy efficiency of MPHD. Taking a MPHD-equipped 2.5-t electric forklift as example, a co-simulation platform is built to demonstrate its performance in a designed cycle based on Chinese standard JB/T3300–2010. Compared with electric forklifts without energy recovery, the MPHD-equipped 2.5-t forklift displays an energy consumption reduction of 28%–35% and a dual energy regeneration efficiency of 73%–76%.

The impact of the driving conditions on stress of load-bearing structure of self-propelled electric mining machine

The paper presents the results of surface-based experimental investigations conducted on a self-propelled electric mining machine powered by a battery pack. The aim of the research was to determine the values of dynamic surpluses occurring during operations and assess the effectiveness of the hydraulic accumulator in the lifting actuator of the operating system. The measurements were performed using three methods: strain gauges, accelerometers, and pressure transducers. Understanding the values of dynamic loads is particularly important as they have a decisive impact on the fatigue durability of the chassis and working system. Typically, pressure is measured in the lifting system (measurement conducted at the hydraulic accumulator). However, the authors have demonstrated that the measurement conducted using the existing pressure transducers on the machine is insufficient and underestimates the values of dynamic loads.