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20 pages, 4630 KiB  
Article
A Novel Flow Characteristic Regulation Method for Two-Stage Proportional Valves Based on Variable-Gain Feedback Grooves
by Xingyu Zhao, Huaide Geng, Long Quan, Chengdu Xu, Bo Wang and Lei Ge
Machines 2025, 13(8), 648; https://doi.org/10.3390/machines13080648 - 24 Jul 2025
Viewed by 253
Abstract
The two-stage proportional valve is a key control component in heavy-duty equipment, where its signal-flow characteristics critically influence operational performance. This study proposes an innovative flow characteristic regulation method using variable-gain feedback grooves. Unlike conventional throttling notch optimization, the core mechanism actively adjusts [...] Read more.
The two-stage proportional valve is a key control component in heavy-duty equipment, where its signal-flow characteristics critically influence operational performance. This study proposes an innovative flow characteristic regulation method using variable-gain feedback grooves. Unlike conventional throttling notch optimization, the core mechanism actively adjusts pilot–main valve mapping through feedback groove shape and area gain adjustments to achieve the desired flow curves. This approach avoids complex throttling notch issues while retaining the valve’s high dynamics and flow capacity. Mathematical modeling elucidated the underlying mechanism. Subsequently, trapezoidal and composite feedback grooves are designed and investigated via simulation. Finally, composite feedback groove spools tailored to construction machinery operating conditions are developed. Comparative experiments demonstrate the following: (1) Pilot–main mapping inversely correlates with area gain; increasing gain enhances micro-motion control, while decreasing gain boosts flow gain for rapid actuation. (2) This method does not significantly increase pressure loss or energy consumption (measured loss: 0.88 MPa). (3) The composite groove provides segmented characteristics; its micro-motion flow gain (2.04 L/min/0.1 V) is 61.9% lower than conventional valves, significantly improving fine control. (4) Adjusting groove area gain and transition point flexibly modifies flow gain and micro-motion zone length. This method offers a new approach for high-performance valve flow regulation. Full article
(This article belongs to the Section Machine Design and Theory)
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37 pages, 1099 KiB  
Review
Application Advances and Prospects of Ejector Technologies in the Field of Rail Transit Driven by Energy Conservation and Energy Transition
by Yiqiao Li, Hao Huang, Shengqiang Shen, Yali Guo, Yong Yang and Siyuan Liu
Energies 2025, 18(15), 3951; https://doi.org/10.3390/en18153951 - 24 Jul 2025
Viewed by 310
Abstract
Rail transit as a high-energy consumption field urgently requires the adoption of clean energy innovations to reduce energy consumption and accelerate the transition to new energy applications. As an energy-saving fluid machinery, the ejector exhibits significant application potential and academic value within this [...] Read more.
Rail transit as a high-energy consumption field urgently requires the adoption of clean energy innovations to reduce energy consumption and accelerate the transition to new energy applications. As an energy-saving fluid machinery, the ejector exhibits significant application potential and academic value within this field. This paper reviewed the recent advances, technical challenges, research hotspots, and future development directions of ejector applications in rail transit, aiming to address gaps in existing reviews. (1) In waste heat recovery, exhaust heat is utilized for propulsion in vehicle ejector refrigeration air conditioning systems, resulting in energy consumption being reduced by 12~17%. (2) In vehicle pneumatic pressure reduction systems, the throttle valve is replaced with an ejector, leading to an output power increase of more than 13% and providing support for zero-emission new energy vehicle applications. (3) In hydrogen supply systems, hydrogen recirculation efficiency exceeding 68.5% is achieved in fuel cells using multi-nozzle ejector technology. (4) Ejector-based active flow control enables precise ± 20 N dynamic pantograph lift adjustment at 300 km/h. However, current research still faces challenges including the tendency toward subcritical mode in fixed geometry ejectors under variable operating conditions, scarcity of application data for global warming potential refrigerants, insufficient stability of hydrogen recycling under wide power output ranges, and thermodynamic irreversibility causing turbulence loss. To address these issues, future efforts should focus on developing dynamic intelligent control technology based on machine learning, designing adjustable nozzles and other structural innovations, optimizing multi-system efficiency through hybrid architectures, and investigating global warming potential refrigerants. These strategies will facilitate the evolution of ejector technology toward greater intelligence and efficiency, thereby supporting the green transformation and energy conservation objectives of rail transit. Full article
(This article belongs to the Special Issue Advanced Research on Heat Exchangers Networks and Heat Recovery)
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28 pages, 9135 KiB  
Article
Performance Analysis of a Reciprocating Refrigeration Compressor Under Variable Operating Speeds
by Willian T. F. D. da Silva, Vitor M. Braga and Cesar J. Deschamps
Machines 2025, 13(7), 609; https://doi.org/10.3390/machines13070609 - 15 Jul 2025
Viewed by 313
Abstract
Variable-speed reciprocating compressors (VSRCs) have been increasingly used in domestic refrigeration due to their ability to modulate cooling capacity and reduce energy consumption. A detailed understanding of performance-limiting factors such as volumetric and exergetic inefficiencies is essential for optimizing their operation. An experimentally [...] Read more.
Variable-speed reciprocating compressors (VSRCs) have been increasingly used in domestic refrigeration due to their ability to modulate cooling capacity and reduce energy consumption. A detailed understanding of performance-limiting factors such as volumetric and exergetic inefficiencies is essential for optimizing their operation. An experimentally validated simulation model was developed using GT-SUITE to analyze a VSRC operating with R-600a across speeds from 1800 to 6300 rpm. Volumetric inefficiencies were quantified using a stratification methodology, while an exergy-based approach was adopted to assess the main sources of thermodynamic inefficiency in the compressor. Unlike traditional energy analysis, exergy analysis reveals where and why irreversibilities occur, linking them directly to power consumption and providing a framework for optimizing design. Results reveal that neither volumetric nor exergy efficiency varies monotonically with compressor speed. At low speeds, exergetic losses are dominated by the electrical motor (up to 19% of input power) and heat transfer (up to 13.5%). Conversely, at high speeds, irreversibilities from fluid dynamics become critical, with losses from discharge valve throttling reaching 5.8% and bearing friction increasing to 6.5%. Additionally, key volumetric inefficiencies arise from piston–cylinder leakage, which causes up to a 4.5% loss at low speeds, and discharge valve backflow, causing over a 5% loss at certain resonant speeds. The results reveal complex speed-dependent interactions between dynamic and thermodynamic loss mechanisms in VSRCs. The integrated modeling approach offers a robust framework for diagnosing inefficiencies and supports the development of more energy-efficient compressor designs. Full article
(This article belongs to the Special Issue Theoretical and Experimental Study on Compressor Performance)
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35 pages, 5144 KiB  
Systematic Review
A Systematic Review of Two-Phase Expansion Losses: Challenges, Optimization Opportunities, and Future Research Directions
by Muhammad Syaukani, Szymon Lech, Sindu Daniarta and Piotr Kolasiński
Energies 2025, 18(13), 3504; https://doi.org/10.3390/en18133504 - 2 Jul 2025
Cited by 1 | Viewed by 351
Abstract
Two-phase expansion processes have emerged as a promising technology for enhancing energy efficiency in power generation, refrigeration, waste heat recovery systems (for example, partially evaporated organic Rankine cycle, organic flash cycle, and trilateral flash cycle), oil and gas, and other applications. However, despite [...] Read more.
Two-phase expansion processes have emerged as a promising technology for enhancing energy efficiency in power generation, refrigeration, waste heat recovery systems (for example, partially evaporated organic Rankine cycle, organic flash cycle, and trilateral flash cycle), oil and gas, and other applications. However, despite their potential, widespread adoption is hindered by inherent challenges, particularly energy losses that reduce operational efficiency. This review systematically evaluates the current state of two-phase expansion technologies, focusing on the root causes, impacts, and mitigation strategies for expansion losses. This work used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Using the PRISMA framework, 52 relevant publications were identified from Scopus and Web of Science to conduct the systematic review. A preliminary co-occurrence analysis of keywords was also conducted using VOSviewer version 1.6.20. Three clusters were observed in this co-occurrence analysis. However, the results may not be significant. Therefore, the extended work was done through a comprehensive analysis of experimental and simulation studies from the literature. This study identifies critical loss mechanisms in key components of two-phase expanders, such as the nozzle, diffuser, rotor, working chamber, and vaneless space. Also, losses arising from wetness, such as droplet formation, interfacial friction, and non-equilibrium phase transitions, are examined. These phenomena degrade performance by disrupting flow stability, increasing entropy generation, and causing mechanical erosion. Several losses in the turbine and volumetric expanders operating in two-phase conditions are reported. Ejectors, throttling valves, and flashing flow systems that exhibit similar challenges of losses are also discussed. This review discusses the mitigation and the strategy to minimize the two-phase expansion losses. The geometry of the inlet of the two-phase expanders plays an important role, which also needs improvement to minimize losses. The review highlights recent advancements in addressing these challenges and shows optimization opportunities for further research. Full article
(This article belongs to the Special Issue Design and Experimental Study of Organic Rankine Cycle System)
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18 pages, 4291 KiB  
Article
Parametric Effects of Mixing Channel Geometry on Entrainment Characteristics of Ejector in R410A Heat Pump Systems
by Yuying Wang, Zhengdao Zhou, Meiyuan Yang, Li Chang, Yang Li and Zhenying Zhang
Processes 2025, 13(6), 1933; https://doi.org/10.3390/pr13061933 - 18 Jun 2025
Viewed by 367
Abstract
The two-phase ejector has gained prominence in heat pump systems as a device that effectively mitigates throttling losses through expansion work recovery. This investigation employs three-dimensional computational fluid dynamics (CFD) simulations to analyze the parametric effects of the mixing channel geometry on the [...] Read more.
The two-phase ejector has gained prominence in heat pump systems as a device that effectively mitigates throttling losses through expansion work recovery. This investigation employs three-dimensional computational fluid dynamics (CFD) simulations to analyze the parametric effects of the mixing channel geometry on the entrainment characteristics in an R410A ejector. After validating the model according to the experimental data, the parameter analysis was carried out, and four key geometric parameters were changed within a certain range: the nozzle exit position (NXP = 13–19 mm), the pre-mixing channel convergent angle (CA = 20–60°), the diameter ratio (DDR = 5.0–7.1), and the length-to-diameter ratio (LDR = 8.9–12.4). Multi-variable optimization studies revealed optimal geometric configurations at NXP = 17 mm (about 3.5Dmix), CA = 30°, DR = 6.4, and LDR = 11.1, yielding an optimized mass entrainment ratio enhancement of 23.6% compared to baseline designs. This research provides actionable guidelines for the design of high-efficiency ejector components for heat pump applications. Full article
(This article belongs to the Section Process Control and Monitoring)
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22 pages, 9118 KiB  
Article
Fault-Tolerant Dynamic Allocation Strategies for Launcher Systems
by Diego Navarro-Tapia, Pedro Simplício and Andrés Marcos
Aerospace 2025, 12(5), 393; https://doi.org/10.3390/aerospace12050393 - 30 Apr 2025
Viewed by 605
Abstract
This article presents fault-tolerant dynamic allocation strategies designed to mitigate propulsion and actuation failures in launch vehicles using a clustered engine configuration. In particular, it addresses engine thrust loss and thrust vector control (TVC) jamming faults during the atmospheric ascent flight of a [...] Read more.
This article presents fault-tolerant dynamic allocation strategies designed to mitigate propulsion and actuation failures in launch vehicles using a clustered engine configuration. In particular, it addresses engine thrust loss and thrust vector control (TVC) jamming faults during the atmospheric ascent flight of a five-engine launch vehicle. Three different strategies are introduced: a fault-tolerant pseudo-inverse solution, a convex optimization-based approach, and a constrained nonlinear optimization one. These approaches are analyzed and compared at a linear design point and further evaluated using a nonlinear simulator of the launcher. The results demonstrate that these three dynamic allocation techniques are able to provide successful recovery from engine thrust loss failures (up to a certain level depending on the engine throttling capability), TVC actuator jamming failures, and simultaneous engine and actuator failures. Full article
(This article belongs to the Special Issue Modeling, Simulation, and Control of Launch Vehicles)
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25 pages, 5908 KiB  
Article
A Modelica-Based Model for Pneumatic Circuits with a Focus on Energy Efficiency
by Gustavo Koury Costa
J. Exp. Theor. Anal. 2025, 3(2), 11; https://doi.org/10.3390/jeta3020011 - 8 Apr 2025
Viewed by 527
Abstract
This paper presents a new computational library for pneumatic circuits, written in the specialized circuit-oriented language “Modelica”, and executed within an open-source IDE, “OpenModelica”, freely available for downloading on the Internet. The library focuses on the problem of energy efficiency and energy savings [...] Read more.
This paper presents a new computational library for pneumatic circuits, written in the specialized circuit-oriented language “Modelica”, and executed within an open-source IDE, “OpenModelica”, freely available for downloading on the Internet. The library focuses on the problem of energy efficiency and energy savings (two different concepts, that we intend to clarify in the text). The idea is to use the Modelica scripts to simulate typical circuits, known by their energy-efficient designs. We reason that air throttling within valves is one of the great challenges when it comes to energy losses. Also, we argue that compressed air reuse can be seen as a means of increasing efficiency, basically through replacing air throttling with counter-pressure velocity control. A simplified version of the developed Modelica library is made available to the reader in the Appendix A, to be used with new scripts and adapted to different realities. In our view, in many situations, open-code Modelica programs may constitute an alternative to proprietary software, where the mathematical models of components are mostly hidden from the end user. Theoretical experiments are carried out, focusing on energy management. The results show that the Modelica library hereby presented is solid, with great prospects of future development. They also show that energy efficiency in pneumatic circuits, at times, comes with the cost of poorly controlled velocity and pressure at the actuator, which requires a careful analysis by the designer, before an actual implementation. Full article
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29 pages, 13959 KiB  
Article
Structural Optimization and Fluid–Structure Interaction Analysis of a Novel High-Speed Switching Control Valve
by Hexi Ji, Jiazhen Han, Yong Wang, Yongkang Liu, Yudong Xie, Sen Yang, Derui Shi and Yilong Song
Actuators 2025, 14(4), 163; https://doi.org/10.3390/act14040163 - 24 Mar 2025
Viewed by 538
Abstract
Laver fluffy is an indispensable link in the processing of laver products. After fluffing, the laver acquires an appealing color, which is conducive to better marketability. During the primary mechanical processing of laver, a valve capable of rapid opening and closing is required [...] Read more.
Laver fluffy is an indispensable link in the processing of laver products. After fluffing, the laver acquires an appealing color, which is conducive to better marketability. During the primary mechanical processing of laver, a valve capable of rapid opening and closing is required to ensure that the laver’s surface becomes fluffy and lustrous post-processing. However, valve products that can meet the specific requirements of laver fluffing are scarce. This study proposes a novel principle for a high-speed switching control valve. This valve can quickly turn on or cut off the high-pressure gas path during laver processing while also taking into account the response speed and service life. The structure and principle of the new control valve were introduced. Different flow field models in the valve were designed, and their flow characteristics and flow field performance under various schemes were compared and discussed by using Fluent. Subsequently, an optimized control valve structure model was proposed. Based on this, a strength analysis of the control valve was conducted via fluid–structure interaction, revealing the response characteristics of the valve under the working state. The results indicate that, when different cone angles and bell shapes were selected for the upper chamber inlet of the control valve, the number and intensity of vortices in the upper chamber can be reduced. The height of the upper chamber affected the formation of the throttle between the top and bottom surfaces of the upper chamber. When the height of the upper chamber was 32 mm, the energy loss in the upper chamber remains basically stable. Simultaneously changing the inlet shape and height of the upper chamber can effectively prevent the throttle formed by the height of the upper chamber, which was conducive to increasing the valve outlet flow rate. Through the analysis of the flow field with different valve chamber structures, the improved control valve adopted the bell-shaped inlet, with an upper chamber height of 32 mm and curved transition for the internal flow channel. Compared to the original fluid domain, when the opening was 100%, the outlet flow rate of the 10° conical tube and bell-shaped inlet increased by 12.77% and 12.59%, respectively. The outlet flow rate at the curved transition position rose by 15.35%, and the outlet flow of the improved control valve increased by 32.70%. When the control valve was operating under a preload pressure of 1 MPa, at 20% opening, the maximum equivalent stress of the valve body was 52.51 MPa, and the total deformation was 12.56 microns. When the preload pressure exceeded 1.5 MPa, the equivalent stress and total deformation of the control valve body and T-shaped valve stem exhibited an upward trend with further increases in the preload pressure. Full article
(This article belongs to the Special Issue Design, Hydrodynamics, and Control of Valve Systems)
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20 pages, 3776 KiB  
Article
Energy-Efficient Hydraulic System for Hexapod Robot Based on Two-Level Pressure System for Oil Supply
by Junkui Dong, Bo Jin, Ziqi Liu and Lei Chen
Biomimetics 2025, 10(3), 151; https://doi.org/10.3390/biomimetics10030151 - 1 Mar 2025
Cited by 1 | Viewed by 691
Abstract
This article proposes a two-level pressure system (TPS) inspired by mammalian energy supply mechanisms to enhance the energy efficiency of hydraulic hexapod robots (HHRs), In contrast to traditional one-level pressure systems (OPSs), the TPS contains both high-pressure and low-pressure oil supplies, which can [...] Read more.
This article proposes a two-level pressure system (TPS) inspired by mammalian energy supply mechanisms to enhance the energy efficiency of hydraulic hexapod robots (HHRs), In contrast to traditional one-level pressure systems (OPSs), the TPS contains both high-pressure and low-pressure oil supplies, which can switch the oil supply pressure according to the actuator load to reduce throttling loss and improve energy efficiency. Additionally, the TPS adopts a separate-meter-in and separate-meter-out (SMISMO) method to manage flow and pressure switching for the actuators. This article also analyzes the energy transfer process of an HHR and establishes kinematic and hydraulic system models. The energy-saving and control performance of the TPS is verified through simulations and experiments. The results show that compared to the OPS, the TPS achieves a 28.8% reduction in energy consumption while imposing higher demands on control performance. Full article
(This article belongs to the Special Issue Optimal Design Approaches of Bioinspired Robots)
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20 pages, 9340 KiB  
Article
Research on Pressure Control of Hydraulic System for Pump Controlled Anchor Drilling Machine Based on Variable Universe Fuzzy PID Algorithm
by Zheng Yan, Guangwei Tang and Youshan Gao
Machines 2025, 13(3), 199; https://doi.org/10.3390/machines13030199 - 28 Feb 2025
Cited by 1 | Viewed by 695
Abstract
To address significant pressure fluctuations in anchor drilling machine systems during the drilling and anchoring support of complex coal roadway surrounding rock, a variable universe fuzzy PID control strategy was proposed to regulate the speed of the servo motor. Additionally, a pump-controlled pressure [...] Read more.
To address significant pressure fluctuations in anchor drilling machine systems during the drilling and anchoring support of complex coal roadway surrounding rock, a variable universe fuzzy PID control strategy was proposed to regulate the speed of the servo motor. Additionally, a pump-controlled pressure approach was introduced to further reduce throttling losses and energy consumption. To validate the proposed algorithm, disturbances were simulated by adjusting the opening size of a three-position four-way proportional directional valve. A co-simulation model was first established using AMESIM 2020.1 and SIMULINK R2022a software, followed by experimental verification and comparison with conventional PID control. The experimental results demonstrated that when the system pressure signal was set to a constant value, the proposed algorithm reduced the pressure error by approximately 36.5% compared to PID control. For step pressure inputs, the algorithm decreased the response time and overshoot by 6.8–8.2% and 10.3–16.2%, respectively, under different valve openings. Furthermore, when the system pressure followed various sinusoidal signals, the proposed algorithm exhibited lower pressure error and faster response times than PID control. This study provides theoretical and experimental references for maintaining stable pressure during the operation of anchor drilling machines, offering an efficient and reliable control solution for complex drilling environments. Full article
(This article belongs to the Section Electrical Machines and Drives)
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24 pages, 4240 KiB  
Article
Digital Hydraulic Transformer Concepts for Energy-Efficient Motion Control
by Helmut Kogler
Actuators 2025, 14(2), 54; https://doi.org/10.3390/act14020054 - 25 Jan 2025
Cited by 1 | Viewed by 951
Abstract
Hydraulic linear drive systems with conventional proportional valves result in poor energy efficiency due to resistance control. In systems with multiple actuators connected to one common pressure supply, a load-sensing strategy is often used to reduce these throttling losses. However, like conventional cylinder [...] Read more.
Hydraulic linear drive systems with conventional proportional valves result in poor energy efficiency due to resistance control. In systems with multiple actuators connected to one common pressure supply, a load-sensing strategy is often used to reduce these throttling losses. However, like conventional cylinder actuators, common load-sensing systems are also not able to recuperate the energy, which is actually released when a dead load is lowered. In order to overcome these drawbacks, in this paper, new concepts of a digital hydraulic smart actuator and a load-sensitive pressure supply unit are presented, which are qualified to reduce throttling losses and, furthermore, to harvest energy from the load. According to previous research, the basic concepts used in this contribution promise energy savings in the range of 30% for certain applications, which is one of the main motivations for this study. The operating principles are based on a parallel arrangement of multiple hydraulic switching converters, representing so-called digital hydraulic transformers. Furthermore, the storage module of the presented load-sensitive pressure supply unit is able to boost the hydraulic power in the common pressure rail beyond the maximum power of the primary motor. For exemplary operating cycles of the smart actuator and the pressure supply unit, a significant reduction in the energy consumption could be shown by simulation experiments, which offers a new perspective for energy-efficient motion control. Full article
(This article belongs to the Special Issue Actuation and Control in Digital Fluid Power)
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19 pages, 7637 KiB  
Article
Design of Ejectors for High-Temperature Heat Pumps Using Numerical Simulations
by Julian Unterluggauer, Adam Buruzs, Manuel Schieder, Verena Sulzgruber, Michael Lauermann and Christoph Reichl
Processes 2025, 13(1), 285; https://doi.org/10.3390/pr13010285 - 20 Jan 2025
Cited by 1 | Viewed by 1346
Abstract
Decarbonization of industrial processes by using high-temperature heat pumps is one of the most important pillars towards sustainable energy goals. Most heat pumps are based on the standard Carnot cycle which includes an expansion valve leading to irreversible dissipation and energetic losses. Especially [...] Read more.
Decarbonization of industrial processes by using high-temperature heat pumps is one of the most important pillars towards sustainable energy goals. Most heat pumps are based on the standard Carnot cycle which includes an expansion valve leading to irreversible dissipation and energetic losses. Especially for high-temperature applications, these losses increase significantly, and a replacement of the conventional throttle valve with an ejector, which is an alternative expansion device, for partial recovery of some of the pressure lost during the expansion, is investigated in this paper. However, designing such a device is complicated as the flow inside is subject to multiphase and supersonic conditions. Therefore, this paper aims to streamline an approach for designing ejectors for high-temperature heat pumps using numerical simulations. To showcase the application of the design procedure, an ejector, which is used to upgrade a standard cycle high-temperature heat pump with the synthetic refrigerant R1233zdE, is developed. To design the ejector heat pump, an interaction between a fast 1D design tool, a 1D heat pump cycle simulation, and a 2D CFD simulation is proposed. An ejector is designed for a sink temperature of 130 °C, which can potentially increase the COP of the heat pump by around 20%. Preliminary measurements at off-design conditions at 100 °C sink temperature are used to validate the design procedure. The pressure distribution inside the ejector is well captured, with relative errors around 4%. However, the motive nozzle mass flow was underpredicted by around 30%. To summarize, the presented approach can be used for designing ejectors of high-temperature heat pumps, although the numerical modeling has to be further developed by validation with experiments to improve the prediction of the motive mass flow. Full article
(This article belongs to the Special Issue Heat and Mass Transfer Phenomena in Energy Systems)
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20 pages, 7542 KiB  
Article
An Investigation of Energy Consumption Characteristics of the Pump-Control System for Electric Excavator Arms
by Aihuan He, Liejiang Wei, Quanfeng Lu and Pengfei He
Appl. Sci. 2024, 14(23), 10791; https://doi.org/10.3390/app142310791 - 21 Nov 2024
Viewed by 879
Abstract
The conventional hydraulic system of excavators suffers from significant valve throttling losses and inadequate matching between the hydraulic power source and the load, which substantially impact the system’s overall energy consumption and severely impede the trend toward electrification and energy efficiency in construction [...] Read more.
The conventional hydraulic system of excavators suffers from significant valve throttling losses and inadequate matching between the hydraulic power source and the load, which substantially impact the system’s overall energy consumption and severely impede the trend toward electrification and energy efficiency in construction machinery. To address this issue, a pump-controlled hydraulic cylinder system has been implemented to replace the original valve-controlled hydraulic system that utilizes a single pump with multiple actuators. The influence of energy conversion efficiency and the speed between the motor and the hydraulic pump under varying load-power conditions has been determined through experimental investigations. Based on these findings, a compound-control strategy is proposed that adjusts the displacement of the hydraulic pump to achieve precise control over the position of the hydraulic cylinder and facilitates both the speed and displacement coordination while ensuring optimal motor speed matching with the load power. This strategy is implemented in the boom pump’s hydraulic cylinder control system. The research findings indicate that this combined-control approach enhances efficiency by approximately 18.9% compared with traditional variable-speed pump-controlled hydraulic cylinder systems. Furthermore, energy consumption is reduced by about 39% compared with the conventional valve-controlled hydraulic system. Full article
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6 pages, 1156 KiB  
Proceeding Paper
Personal Watercraft Remote Control Communication Fault Detection
by Ádám Titrik
Eng. Proc. 2024, 79(1), 8; https://doi.org/10.3390/engproc2024079008 - 29 Oct 2024
Viewed by 499
Abstract
Hydroflight is a watersport where the user utilizes a waterjet-propelled backpack to fly over water. These backpacks are usually powered by purpose-built equipment but can also be propelled by personal watercraft. To have full control over movement during hydroflight, the user needs to [...] Read more.
Hydroflight is a watersport where the user utilizes a waterjet-propelled backpack to fly over water. These backpacks are usually powered by purpose-built equipment but can also be propelled by personal watercraft. To have full control over movement during hydroflight, the user needs to adjust the throttle of the watercraft, which is commonly performed by converting the system to remote-controlled operation. However, care should be taken during conversion to ensure safe operation and avoid harm to the user. This paper presents a failure analysis of sudden safety mode activation on a personal watercraft converted to remote control for hydroflight applications, as well as actions taken to avoid full shutdown in the case of communication loss, without compromising user safety. Full article
(This article belongs to the Proceedings of The Sustainable Mobility and Transportation Symposium 2024)
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21 pages, 9299 KiB  
Article
Implementing PSO-LSTM-GRU Hybrid Neural Networks for Enhanced Control and Energy Efficiency of Excavator Cylinder Displacement
by Van-Hien Nguyen, Tri Cuong Do and Kyoung-Kwan Ahn
Mathematics 2024, 12(20), 3185; https://doi.org/10.3390/math12203185 - 11 Oct 2024
Cited by 4 | Viewed by 1425
Abstract
In recent years, increasing attention has been given to reducing energy consumption in hydraulic excavators, resulting in extensive research in this field. One promising solution has been the integration of hydrostatic transmission (HST) and hydraulic pump/motor (HPM) configurations in parallel systems. However, these [...] Read more.
In recent years, increasing attention has been given to reducing energy consumption in hydraulic excavators, resulting in extensive research in this field. One promising solution has been the integration of hydrostatic transmission (HST) and hydraulic pump/motor (HPM) configurations in parallel systems. However, these systems face challenges such as noise, throttling losses, and leakage, which can negatively impact both tracking accuracy and energy efficiency. To address these issues, this paper introduces an intelligent real-time prediction framework for system positioning, incorporating particle swarm optimization (PSO), long short-term memory (LSTM), a gated recurrent unit (GRU), and proportional–integral–derivative (PID) control. The process begins by analyzing real-time system data using Pearson correlation to identify hyperparameters with medium to strong correlations to the positioning parameters. These selected hyperparameters are then used as inputs for forecasting models. Independent LSTM and GRU models are subsequently developed to predict the system’s position, with PSO optimizing four key hyperparameters of these models. In the final stage, the PSO-optimized LSTM-GRU models are employed to perform real-time intelligent predictions of motion trajectories within the system. Simulation and experimental results show that the model achieves a prediction deviation of less than 3 mm, ensuring precise real-time predictions and providing reliable data for system operators. Compared to traditional PID and LSTM-GRU-PID controllers, the proposed controller demonstrated superior tracking accuracy while also reducing energy consumption, achieving energy savings of up to 10.89% and 2.82% in experimental tests, respectively. Full article
(This article belongs to the Special Issue Multi-Objective Optimization and Applications)
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