Browse Topic: Fluid power systems

Items (3,872)
A reconfigurable experimental seat is useful for seating comfort research and allows researchers to investigate the effects of seat parameters and to propose quantitative guidelines for improving seat comfort. Since 2017, Gustave Eiffel University has such an experimental seat which allows us to carry out parametric studies on the geometric dimensions of a seat and to understand the role of the contact force, particularly that in shear force. Equipped with force and positioning sensors, all contact forces and seat position can be measured. More specifically, it is equipped on the seat with a matrix of 52 cylinders, each adjustable in height and each equipped with a three-axis force sensor. These cylinders make it possible to vary the contact surface of seat pan and measure the distribution of contact forces. More recently, a new system with a matrix of 263 hydraulic cylinders was designed and manufactured to better study the comfort of the backrest in replacement of the three-support
Wang, XuguangBeurier, Georges
Automatic transmission (AT) is a complex hydroelectromechanical system, since it consists of hydraulic, electrical and mechanical parts. On cars produced by “UzAuto Motors” mainly AT of the 6T family, 6-speed AT family GM: 6T30, 6T40, 6T45, 6T50 “Hydra-Matic” are used. Production of parts of these transmissions is carried out both at American GM plants and at GM plants in China and Korea. The differences between AT 6T30/6T40/6T45/6T50 are in the thickness of the output chain and in the planetary gear, in the sizes of some other units and the housing itself. But the differences are much more influenced by the settings of the transmission unit, which select operating modes with different engines so as not to overload the thinnest places of the automatic transmission. Automatic transmissions 6T30, 6T40, 6T45, 6T50 have the ability to manually shift gears and activate the “kickdown” mode (for quick acceleration of the car, when you sharply press the gas “all the way” it makes the automatic
Turakulov, Bakhtiyor
This study presents a control co-design method that utilizes a bi-level optimization framework for parallel electric-hydraulic hybrid powertrains, specifically targeting heavy-duty vehicles like class 8 semi-trailer trucks. The primary objective is to minimize battery energy consumption, particularly under high torque demand at low speed, thereby extending both battery lifespan and vehicle driving range. The proposed method formulates a bi-level optimization problem to ensure global optimality in hydraulic energy storage sizing and the development of a high-level energy management strategy. Two nested loops are used: the outer loop applies a Genetic Algorithm (GA) to optimize key design parameters such as accumulator volume and pre-charged pressure, while the inner loop leverages Dynamic Programming (DP) to optimize the energy control strategy in an open-loop format without predefined structural constraints. Both loops use a single objective function, i.e. battery energy consumption
Taaghi, AmirhosseinYoon, Yongsoon
This SAE Aerospace Recommended Practice (ARP) provides recommendations on cavity design, the installation of elastomer type spare seals in these cavities, and information surrounding elastomer material properties after contact with typical shock absorber hydraulic fluid(s) or grease. This ARP is primarily concerned with the use of spare seals on shock absorbers where only a single dynamic seal is fitted and in contact with the slider/shock absorber piston at any one time. These shock absorbers typically have a spare (dynamic) seal gland located on the outer diameter of the lower seal carrier. This spare seal gland is intended to house a spare elastomer contact seal. Split Polytetrafluoroethylene (PTFE) backup rings can also be installed in the spare seal cavity. During operation, if the fitted dynamic shock absorber standard seal begins to fail/leak, then the aircraft can be jacked up, allowing the lower gland nut of the shock absorber to be dropped down. The current used dynamic seal
A-5B Gears, Struts and Couplings Committee
This SAE Aerospace Standard (AS) establishes the minimum performance standards for equipment used as secondary alternating current (AC) electrical power sources in aerospace electric power systems.
AE-7B Power Management, Distribution and Storage
This material type has resistance to hot air, but generally has poor resistance to fuels and lubricants, but usage is not limited to such applications. Each application should be considered separately. This material type has a typical service temperature range of -85 to 500 °F (-65 to 260 °C). The operating temperature range of the material is a general temperature range, but the presence of particular fluids and design parameters may modify this range. Recommendations on the material selection are based on available technical data and are offered as suggestions only. Each user should make his own tests to determine the suitability for his own particular use.
A-6C2 Seals Committee
The Tractor is essential in both agriculture and construction, equipped with a variety of implements for different operational conditions. Its hydraulic system is crucial for controlling these implements during fieldwork and transport. The quadrant assembly is a key part of the tractor’s hydraulic control system, allowing the operator to manage important functions. This includes hydraulic control and draft control, enabling the farmer or operator to use the PC and DC levers to adjust the movement of implements during various tasks. Tractors are commonly used in fields and farms where the soil can be loose and muddy, particularly during wet puddling operations. In these muddy conditions, tractors can accumulate mud in critical components, such as the quadrant assembly. This can lead to functional issues, increased friction, and problems within the hydraulic system, especially affecting the controls for hydraulics and lever shifting for implement handling. As a result, operators may need
K, BheshmaPhadtare, YogeshGomes, MaxsonV, Ashok KumarPerumal, SolairajMagendran, G
Hydropneumatic Struts (HPS) are widely implemented in automobile, aerospace, and construction industries, mainly for the purpose of vibration and shock absorption. The HPS design with integrated gas–oil chamber is relatively more compact and robust, while mixing gas and oil inside the HPS generates gas–oil emulsion and more nonlinearities. This study formulated a nonlinear analytical model of the compact HPS with gas–oil emulsion, considering the real gas law and pressure-dependent LuGre friction model. The polytropic version of the van der Waals (vdW) method for real gas is applied to represent the thermodynamic behavior of nitrogen. The experimental data were collected at a near temperature of 30°C with three charging pressures under excitations in the frequency range of 0.5–6 Hz, considering two flow connection configurations between chambers as one- and two-bleed orifice. The nonlinear behavior of the gas volume fraction of the emulsion was identified based on peak strut velocity
Seifi, AbolfazlYao, YumengYin, YumingMoore, MasihRakheja, Subhash
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from the working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid.
A-6C1 Fluids and Contamination Control Committee
This specification covers requirements for the superfinishing of High Velocity Oxygen/Fuel (HVOF) applied tungsten carbide thermal spray coatings.
AMS B Finishes Processes and Fluids Committee
This SAE Aerospace Information Report (AIR) discusses the forms that air may take in aircraft hydraulic systems. Further, the effects of the various air forms on system operation are addressed. Recommended system design to prevent air effects and maintenance procedures to prevent and remove air are provided. Nitrogen leakage from accumulators is also a source of gas in hydraulic systems and may compose a portion of the “air” in the hydraulic system. The term “air” in this report does not differentiate between a gas composed strictly of normal atmospheric air or one that includes a mixture of additional nitrogen as well. The discussions of the report apply equally with any proportions of atmospheric air and nitrogen in the system.
A-6C1 Fluids and Contamination Control Committee
Autonomous vehicles for mining operations offer increased productivity, reduced total cost of ownership, decreased maintenance costs, improved reliability, and reduced operator exposure to harsh mining environments. A large flow of data exists between the remote operation and the ore haul vehicle, and part of the data becomes information for the maintenance sector which it monitors the operating conditions of various systems. One of the systems deserving attention is the suspension system, responsible for keeping the vehicle running and within a certain vibration condition to keep the asset operational and productive. Thus, this work aims to develop a digital twin-assisted system to evaluate the harmonic response of the vehicle’s body. Two representations were created based on equations of motion that modeled the oscillatory behavior of a mass-damper system. One of the representations indicates a quarter of the ore transport truck’s hydraulic system in a healthy state, called a virtual
Rosa, Leonardo OlimpioBranco, César Tadeu Nasser Medeiros
This paper aims to describe a quarter-car suspension test bench automation process to be utilized in an academic environment. The project is made up of pneumatic system modeling and control system design. An analysis of the bench’s pneumatic system is carried out. This pneumatic system is composed of a pneumatic actuator and a proportional directional control valve, which are responsible for generating the road profile. It is proposed a model to compensate the non-linearities present in the pneumatic system measurement process and the disturbances caused by the under test suspension system, as well as a control strategy for small displacements of the load through linear control approaches, which provide the necessary flexibility to directly influence the parameters affecting the dynamics of the excitation system platform’s displacement, thereby reducing the complexity of the controller design to be adopted. Furthermore, analyses are conducted on the effectiveness of the control in
Siqueira, Matheus AmaralGomes, Pedro CarvalhoTeixeira, Evandro Leonardo SilvaFortaleza, Eugênio Libório FeitosaMorais, Marcus Vinicius Girão
The traditional braking system has been unable to meet the redundant safety requirements of the intelligent vehicle for the braking system. At the same time, under the change of electrification and intelligence, the braking system needs to have the functions of braking boost, braking energy recovery, braking redundancy and so on. Therefore, it is necessary to study the redundant braking boost control of the integrated electro-hydraulic braking system. Based on the brake boost failure problem of the integrated electro-hydraulic brake system, this paper proposes a redundant brake boost control strategy based on the Integrated Brake Control system plus the Redundant Brake Unit configuration, which mainly includes fault diagnosis of Integrated Brake Control brake boost failure, recognition of driver braking intention based on pedal force, pressure control strategy of Integrated Brake Control brake boost and pressure control strategy of Redundant Brake Unit brake boost. The designed control
Dexing, LaoLuping, YanQinghai, SuiLong, CaoShang, GaoZhigang, ChenMingxing, RenZhicheng, Chen
This specification covers the design and installation requirements for Type I and II military aircraft hydraulic systems.
A-6A2 Military Aircraft Committee
Caterpillar has released a cavalcade of new compact track loaders and skid steer loaders. The new CTL models include the 275, 275 XE, 285 and 285 XE. These models join the lineup alongside the 255 and 265, which were introduced last year (www.sae.org/news/2024/02/cat-compact-loaders). The 285 and 285 XE are the largest CTLs Caterpillar has ever produced and reportedly feature greater lift height and lift and tilt breakout forces. “We are excited to launch the next-generation design for our skid steer loader line and expand the performance capabilities to more compact track loader models,” said Trevor Chase, senior product consultant and new product introduction lead for Caterpillar. “Their increased power, lift height, breakout forces, rated operating capacity (ROC) and multiple high-flow auxiliary hydraulic system options give customers a flexible, high-performance machine to get the job done.”
Wolfe, Matt
This SAE Information Report is primarily to familiarize the designer of hydraulic powered machinery with the necessity for oil filtration in the hydraulic power circuit, the degree of system cleanliness required, types of filtration and filters available, and their location and maintenance in the hydraulic circuit.
CTTC C1, Hydraulic Systems
To describe laboratory methods for determining and reporting the contaminant level of the wetted portion of hydraulic fluid power components, parts, subsystems and systems, and of fill fluids. For each type of item, it provides a method of obtaining the liquid sample and the contamination level thereof. It also includes procedures for establishing a sampling plan and guidelines for establishing levels of acceptance, but does not set those levels.
CTTC C1, Hydraulic Systems
This test code describes tests for determining characteristics of hydraulic positive displacement motors as used on off-road self-propelled work machines as referenced in SAE J1116.
CTTC C1, Hydraulic Systems
Air suspension systems are increasingly in demand in high-end cars due to their ability to vary ride height based on vehicle loads, road conditions, and speeds. This trend has driven manufacturers to enhance the performance of these systems. Predicting and optimizing the performance of the air spring system for various vehicle loads and conditions has become essential. The performance of an air suspension system is typically measured by its ability to suspend the vehicle within a specified target time. Therefore, it is necessary to model the air spring system—including the air spring, compressor, pneumatic lines, and valves—and integrate it with the vehicle. This modeling helps in predicting performance and optimizing the system. Additionally, a validated system model enables other important calculations, such as sizing the valves, pneumatic hoses, and compressors. In this study, a complete air spring system model has been developed alongside a 15-degrees-of-freedom car chassis to
Ahmed, Saad AnwarHupfeld, JanRajput, Brijesh
This SAE Aerospace Recommended Practice (ARP) provides an overview of the various types of polytetrafluoroethylene (PTFE) backup rings for hydraulic and pneumatic fluid power applications, including their advantages and disadvantages.
A-6C2 Seals Committee
This Aerospace Information Report (AIR) is limited in scope to the general consideration of environmental control system noise and its effect on occupant comfort. Additional information on the control of environmental control system noise may be found in 2.3 and in the documents referenced throughout the text. This document does not contain sufficient direction and detail to accomplish effective and complete acoustic designs.
AC-9 Aircraft Environmental Systems Committee
This SAE Aerospace Recommended Practice (ARP) describes a method of conducting an endurance test using contaminated air when the applicable specification requires non-recirculation of the contaminants. The objective of the test is to determine the resistance of the engine mounted components to wear or damage caused by the contaminated air. The method described herein calls for non-recirculation of the contaminants and is intended to provide a uniform distribution of the contaminant at the inlet to the Unit Under Test (UUT). The UUT may require the use of a hydraulic fluid for actuation of components within the test unit. Contamination of the test hydraulic fluid is not part of this recommended practice. If contaminated hydraulic fluid is required by the applicable test specification, refer to MAP749.
AC-9 Aircraft Environmental Systems Committee
A well-designed cooling system is crucial in construction machines for efficient heat dissipation from vital components, including the Radiator(RAD), Oil Cooler (OC) and Intercooler (IC). The radiator ensures optimal engine performance and longevity by maintaining a stable operating temperature. Oil Coolers preserve hydraulic system efficiency. Inter Coolers optimize engine performance through denser intake air. The robust cooling system enhances system reliability, reduces downtime, avoid overdesigned system, and increases operator safety in demanding construction environments. The size and location of heat exchangers are critical in cooling system design. Using 1D simulation tool KULI for cooling system design offers the benefits of comprehensive system simulation, optimization of thermal management, reduced development time and costs, enhanced system reliability, improved integration with other systems, and real-world testing and validation. The tool enables time and cost-effective
Dewangan, NitinKattula, NitinGoklani, Mohit
To provide a method by which to assess the cleanliness of new hydraulic fluids. The method is applicable to new mineral and synthetic hydraulic fluids - regardless of packaging. This SAE Standard is not intended as a procedure for operating equipment.
CTTC C1, Hydraulic Systems
This SAE Standard covers specifications and performance requirements for 37-degree and 45-degree single and double flares for tube ends intended for use with SAE J512, SAE J513, SAE J514, and ISO 8434-2 connectors. The flares described in this document are intended for use with SAE metallic tube materials. Considerations such as the effects of wall thickness selection for specific working pressures, identifying the appropriate length of thread engagements for specific applications with mating connectors, and other associated criteria shall be the responsibility of the user. For applicable nominal reference working pressures for hydraulic tubing, refer to SAE J1065 and ISO 10763. In an effort to standardize within a global marketplace and ensure that companies can remain competitive in an international market, it is the intent of this document to promote the use of metric tube and connector sizes, which will: Lead to one global system. Guide users to a preferred system. Reduce
Hydraulic Tube Fittings Committee
This SAE Aerospace Information Report (AIR) describes the aspects of hydraulic system design and installation to minimize the effects of lightning. Techniques for effective electrical bonding, hydraulic system lightning protection, and lightning protection verification techniques are discussed.
A-6A1 Commercial Aircraft Committee
This specification establishes the design, performance, and test requirements for hydraulic quantity measuring fuses intended to be used for hydraulic circuit protection.
A-6C5 Components Committee
Hydraulic systems in aircraft largely comprise of metallic components with high strength to weight ratios. Some examples of such material include Aluminum and Titanium alloys which are typically chosen for low and high-pressure applications respectively. For aircraft fluid conveyance products, hydraulic conduits are fabricated by axisymmetric turning to support flow conditions. The hydraulic conduits can have grooved interfaced design within for placement of elastomeric sealing components. This article presents a systematic study carried out on common loads experienced by fluid carrying conduits and the failure modes induced. Firstly, a static structural analysis was carried out on each of the geometries of the test articles to identify the locations having areas of high stress concentration. Test articles of various wall thicknesses and internal diameters were pressure impulse tested at different conditions of side loads to identify cycle numbers till failure and failure locations. On
Paidimarri, VishalJacob, KrupaHarish, UppuHovis, David
Electrification isn't just a matter of switching out the diesel engine for an electric motor. It requires a thorough review of connected systems - particularly the hydraulic system. Using the same components in electric machines as those used in conventional machines often requires more battery power or a larger electric motor. For this reason, OEMs have discovered the need to rethink efficiency and productivity when electrifying machines. MPG Makine Prodüksiyon Grubu learned this firsthand when designing a truck-mounted electric crane for one of its Netherlands-based customers. The Konya, Turkey-based OEM produces truck-mounted hydraulic cranes with folding and telescopic booms as well as aerial work platforms and tree trans-planter machines.
Avci, Gökhan
This specification covers an acrylonitrile-butadiene (NBR) elastomer that can be used to manufacture product in the form of sheet, strip, tubing, extrusions, and molded shapes. For molded rings, compression seals, O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications, use the AMS-P-83461 specification or the MIL-PRF-25732 specification.
AMS CE Elastomers Committee
This SAE Aerospace Information Report (AIR) lists military and industry specifications, standards, recommended practices, and information reports applicable to aerospace hydraulic and pneumatic systems and components.
A-6 Aerospace Actuation, Control and Fluid Power Systems
The automatic transmission of a specialized vehicle encountered challenges in achieving stable oil filling time due to the considerable variability of related parameters and the non-linear trends in the variation of individual product parameters over time. To investigate the underlying causes of this phenomenon and enhance the oil filling efficiency, a detailed model of the clutch oil filling process during gear shifting was established in this paper, which included dynamic models of the key components such as the hydraulic system, clutch, proportional valve, and oil passages. Physical experiments were performed on the test bench to compare with the simulation results. The results showed that the correlation between the simulation model and the test bench was well, which verified the effectiveness of the simulation model. Based on analyzing the clutch filling process, the effects of parameters such as orifice diameter, piston cavity clearance, clutch gap, and oil injection pressure on
Guo, JunFeng, GuangjunWu, JinglaiZhang, Yunqing
Positive displacement pumps are key components in automotive and hydraulic fluid systems, often serving as the primary power source and a major source of noise in both on-highway and off-highway vehicles. Specifically, gerotor pumps are widely utilized in vehicle coolant, lubricating, and other fluid systems for both conventional and electric powertrains. This study introduces a novel method for predicting noise in gerotor pumps by combining a Computational Acoustics (CA) approach with a 3D Computational Fluid Dynamics (CFD) approach, both implemented in the Simerics–MP+ code. The CFD simulation includes the detailed transient motion of the rotors (including related mesh motion) and models the intricate cavitation/air release phenomena at varying pump speeds. The acoustic simulation employs a Ffowcs–Williams Hawkings (FW–H) integral formulation to predict sound generation and propagation based on the detailed flow field predictions from the CFD model. Simulations of two different
Taghizadeh, SalarNg, Kok ChianHoren, JezrahDhar, Sujan
A semi-active suspension system provides superior safety, ride, and handling performance for a vehicle by continuously varying the damping based on vehicle motions, where semi-active hydraulic damper (SAHD) is the most critical component. Today, SAHD’s are standard in most of the premium segments of vehicles and optional extras in mid-size and compact vehicle segments. Electric vehicles require larger sized SAHD’s to meet heavier vehicle loads and meet ride and handling requirements. The aim of this paper is to highlight the design and development methodology of a base valve for larger bore-size for semi-active hydraulic damper. The workflow follows to present a process for base valve design to meet structural strength and, the key steps of design calculations of the hydraulic performance. The design of the base valve and suction disks architecture was engineered with the aid of Computer Aided simulations. The structural performance was analyzed using the Finite Element Analysis (FEA
Chintala, ParameshPatwa, AakashSankaran, Shivanand
This paper details testing for torque converter clutch (TCC) characterization during steady state and dynamic operation under controlled slip conditions on a dynamometer setup. The subject torque converter under test is a twin plate clutch with a dual stage turbine damper without a centrifugal pendulum absorber. An overview is provided of the dynamometer setup, hydraulic system and control techniques for regulating the apply pressure to the torque converter and clutch. To quantify the performance of the clutch in terms of control stability, pressure to torque relationship and the dynamic behavior during apply and release, a matrix of oil temperatures, output speeds, input torques, and clutch apply pressures were imposed upon the torque converter. The torque capacity of the clutch is estimated with the dimensions of the friction surfaces and pressure plate and an enhanced lookup data of K-factor obtained through testing of the hydrodynamics at input torques from 10 to 200 Nm over a
Robinette, DarrellBlough, JasonJurmu, LukeReynolds, CraigScheich, Andrew
DHT hybrid transmission assembly control system discussed in this paper includes hydraulic control, hybrid mode switching control, shift control, dual motor control, clutch and motor thermal management. The hybrid mode is divided into four modes: the EV mode, the serial mode, the parallel mode and the launch mode. Hydraulic control includes torque-pressure conversion, clutch pressure kiss point adaption, clutch oil filling time adaption. Shift control includes shift type decision, shift sequence control, shift inertia process based on motor intervention. Thermal management includes clutch flow and motor flow distribution. Motor control include the current control, mode control and boost strategy of permanent magnet synchronous motor in dual hybrid system, which has good stability and robustness. Motor mode includes initialization mode, normal mode, fault mode, active discharge mode, power off mode. The boost strategy of the hybrid system is based on boost mode management, boost target
Jing, JunchaoZhang, JunzhiLiu, YiqiangWang, ZhentaoXue, Tianjian
This document defines the requirements for weld fittings and machine weldments using an orbiting welding head suitable for use on cold worked 3AL-2.5V titanium, 21Cr-6Ni-9Mn CRES, and 718 nickel alloy tubing. Fitting standards covered by this specification include non-separable welded elbow, tee, and reducer fittings, and reconnectable 24-degree cone fittings, such as sleeves and unions.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Throughout the automobile industry, the electronic brake boost technologies have been widely applied to support the expansion of the using range of the driver assist technologies. The electronic brake booster (EBB) supports to precisely operate the brakes as necessary via building up the brake pressure faster than the vacuum brake booster. Therefore, in this article a novel control strategy for the EBB based on fuzzy logic control (FLC) is developed and studied. The configuration of the EBB is established and the system model including the permanent magnet synchronous motor (PMSM), a two-stage reduction transmission (gears and a ball screw), a servo body, reaction disk, and the hydraulic load are modeled by MATLAB/Simulink. The load-dependent friction has been compensated by using Karnopp friction model. Due to the strong nonlinearity on the EBB components and the load-dependent friction, FLC has been used for the control algorithm. The control concept focused on transforming the
Soliman, Amr M.E.Kaldas, Mina M.Soliman, Aref M.A.Huzayyin, A.S.
Active suspension systems employ sophisticated control algorithms to deliver superior comfort in vehicles. However, the capabilities of these algorithms are limited by the physical constraints of actuators. Many vehicles use hydraulic actuators in their active suspension system, which use fluid movement to control suspension motion. These systems inherently have slower response times due to the nature of fluid flow and the time required to build up or release pressure within the hydraulic system. Typically, hydraulic systems operate in a low bandwidth of 0-5 Hz. This limits their capability to only meeting vehicle’s primary ride targets which typically lie below 5 Hz. Although they can be tuned to operate at a slightly higher frequency range (up to 10 Hz), they perform poorly in attenuating the secondary ride vibration, i.e., 5 – 25 Hz. This paper focuses on investigating the possible hardware and subsequently control capabilities that can allow us to affect the vehicle ride well
Agrawal, AyushNegi, AyushJoshi, Divyanshu
This paper presents a virtual analysis method for pressure spike estimation and optimization of hydraulic system architecture for off-highway applications with hydraulically actuated clutch. This pressure spike leads to a very high torque spike in driveline components during clutch pop-up conditions in puddling operations. These torque spikes lead to potential failure of driveline components i.e., gear, shaft, bearing and torsional damper during sudden engagement events. To assess the hydraulic system performance during clutch pop-up cornering conditions is very challenging and leads to compromise on operator safety in the paddy field. It is essential to develop a simulation methodology in a virtual environment to understand the system behavior during clutch pop-up condition and impact of various hydraulic system parameters. This paper describes a Model Based System Design (MBSD) approach for understanding hydraulic system pressure spike phenomenon and dynamic response. Pressure spike
Memane, NileshKumar, SuneelVeerkar, Vikrant
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