Browse Topic: Hydraulic control
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
In recent days the usage of Electro - Hydraulic Control Unit (EHCU) is increased acutely in light passenger vehicle applications apart from the passenger cars. The main advantage of using electro - Hydraulic control unit (EHCU) is operational flexibility, consistent performance customization, increase durability and lower running cost. During running, the mechanical load is converted into the electronic signal by using transmitter. The electronic devices are highly responsive when compared with mechanical devices, so, it is necessary to reduce the Noise, Vibration and Harshness (NVH) in the system. As per the recent trend, the NVH pollution should be as low as possible in the vehicle. It is necessary to maintain the NVH in minimum level in the electronic device to meet the overall performance of the system. The vibrational isolator is one of the key components used in Electro – Hydraulic Control Unit to reduce the noise and vibration implication of the system. The process of using
This SAE Aerospace Information Report presents the following factors that affect hydraulic pump life and performance: a The need to supply hydraulic fluid at the correct pressure and quality to the pump inlet port b Considerations for the pump output c Factors to be considered for the pump case drain lines d The mounting of the hydraulic pump e Hydraulic fluid properties, including cleanliness
This SAE Standard includes only those towing winches commonly used on skidders and crawler tractors. These winches are used on self-propelled machines described in SAE J1057, J1116, and J1209. Specifically excluded are those winches used for hoisting operations.
Dual Clutch Automatic Transmission (DCT) has the characteristics of light weight, fast shift speed and high transmission efficiency. Electric vehicles equipped with dual clutch transmission can effectively improve vehicle power performance and economy. Electro-hydraulic control system, as a key component of transmission, determines the quality of shift. In this paper, an electro - hydraulic control system is designed based on two - speed dry dual clutch transmission of electric vehicle. Firstly, the hydraulic components of the system were selected and calculated based on the vehicle parameters. Secondly, the electro-hydraulic control system of the dual clutch transmission was established according to the transmission control strategy and the matching hydraulic valve body assembly was designed. Then, the key components of the system were simulated to analyze their dynamic shift characteristics and response characteristics. Finally, through various tests, it is verified that the designed
In order to meet upcoming emission targets, an increasing number of ships using Liquefied Natural Gas (LNG) as fuel have been put into service. In this context, many shipowners are particularly interested in the dual-fuel (DF) large-engine technology, which enables ships to operate with both gaseous and conventional liquid fuels. The use of different combustion principles in DF engines requires a layout of the base engine with a relatively low compression ratio (CR) for the gas mode to prevent unstable combustion (knocking). However, this layout leads to disadvantages in the Diesel operation mode, which requires a higher CR for optimal fuel efficiency. Therefore, a two-stage variable compression ratio (VCR) system is a technology particularly suitable for DF engines. It allows to reduce fuel costs by approximately 5.5%. This article presents an innovative VCR connecting rod (conrod) design for modern DF engines that adapts the piston position by changing the effective conrod length
With the development of intelligent and electric vehicles, higher requirements are put forward for the active braking and regenerative braking ability of the braking system. The traditional braking system equipped with vacuum booster has difficulty meeting the demand, therefore it has gradually been replaced by the integrated braking system. In this paper, a novel Integrated Braking System (IBS) is presented, which mainly contains a pedal feel simulator, a permanent magnet synchronous motor (PMSM), a series of transmission mechanisms, and the hydraulic control unit. As an integrative system of mechanics-electronics-hydraulics, the IBS has complex nonlinear characteristics, which challenge the accurate pressure control. Furthermore, it is a completely decoupled braking system, the pedal force doesn’t participate in pressure-building, so it is necessary to precisely identify driver’s braking intention. To improve the control accuracy of the system, this paper proposed a novel pressure
The RADIALcvt is a traction drive continuously variable transmission (CVT) implemented in a new novel radial configuration mechanical assembly. The RADIALcvt functions as a multi-parallel power path (at least six) type of CVT, which consists of only one steel-on-steel, line contact, traction drive interface in each power path. A constant input radius on the traction drive input makes it possible to use a constant clamping force, which is provided by mechanical springs, thus eliminating the need for a hydraulic control system. The RADIALcvt has a very large radius variation on the traction drive output, which provides the ratio variation. The test and simulation results of the first RADIALcvt prototype was published in [1] and presented mechanical efficiencies above 90%. This article presents the simulation and test results of the second-generation RADIALcvt prototype, which presents mechanical efficiencies above 94% and includes measured parameters of mechanical efficiency, slip
This study aims to solve the problem of impact in a parallel hybrid electric system based on the continuously variable transmission (CVT) during switching from pure electric mode to engine-driven, power-generating mode. Taking into account the torque response characteristics of the engine and motor and the dynamic characteristics of the wet clutch hydraulic control system, the mode switching process is divided into six stages, namely, pure electric mode, wet-clutch free travel, engine start-up, engine speed synchronization, clutch combination, and engine intervention drive. A coordination control strategy is developed based on the model predictive control algorithm to ensure smooth mode switching. The effectiveness of the control algorithm is verified using Matlab/Simulink and the AMESim co-simulation platform. Results show that with the mode switching coordination control strategy, the components of the system work harmoniously. The maximum impact is reduced by 52.0% at the speed
The latest trend in transmission hydraulic controls development ise body integrated direct acting control solenoid, ted by multiple automotive OEMs. The advantages of integrated direct acting control solenoids are key enablers for OEMs to meet more and more stringent fuel economy requirement and competitive environment. In the meantime, there are unique challenges in both designing and manufacturing of such solenoids, due to the fact the solenoid armature can only push the spool valve with limited force and limited stroke. Through analytical methods, this paper explains design guidelines to overcome the challenges and quantifies the impact of design decision to critical functional objectives. Multiple valve design configurations, including both normally low and normally high functionality, are covered in the analysis. Unique manufacturing process concerns are also addressed.
SAE J1939-2 specifies the requirements for application of SAE J1939 in agricultural and forestry equipment. This document specifies the series of documents within the set of SAE J1939 documents that are applicable to agricultural and forestry equipment and provides further requirements for this industry. The SAE and ISO groups have cooperated to define agricultural and forestry networks in a manner to allow compatibility of ECUs and messaging protocols between the A&F and the T&B networks.
In the process of ABS control, the Anti-lock braking system (ABS) of the vehicle adjusts the wheel cylinder brake pressure through the hydraulic actuator so as to control the movement of the wheel. The high-speed on-off valve (HSV) is the key components of the Anti-lock braking system. HSV affects the performance of the hydraulic actuator and the valve response characteristics affects the Anti-lock braking system pressure response as well as braking effect. In this paper, the electromagnetic field theory and flow field theory of HSV are analyzed, and simulation analysis of electromagnetic field characteristics of HSV is done by ANSYS. Combined with the ANSYS analysis results, a precise physical model of HSV is constructed in AMESim. Meanwhile, the valve response characteristics are analyzed. Moreover, the influence of different wheel cylinder diameter and PWM carrier frequency on hydraulic braking force characteristics are analyzed. The open-loop control methods of hydraulic braking
This SAE Aerospace Information Report (AIR) provides design information of various contemporary aircraft fly-by-wire (FBW) flight control actuation systems that may be useful in the design of future systems for similar applications. It is primarily applicable to manned aircraft. It presents the basic characteristics, hardware descriptions, redundancy concepts, functional schematics, and discussions of the servo controls, failure monitoring, and fault tolerance. All existing FBW actuation systems are not described herein; however, those most representing the latest designs are included. While this AIR is intended as a reference source of information for aircraft actuation system designs, the exclusion or omission of any other appropriate actuation system or subsystem should not limit consideration of their use on future aircraft.
This SAE Standard includes only those towing winches commonly used on skidders and crawler tractors. These winches are used on self-propelled machines described in SAE J1057, J1116, and J1209. Specifically excluded are those winches used for hoisting operations.
Fuel economy regulations have forced the automotive industry to implement transmissions with an increased number of gears and reduced parasitic losses. The objective of this research is to develop a high fidelity and a computationally efficient model of an automatic transmission, this model should be suitable for controller development purposes. The transmission under investigation features a combination of positive clutches (interlocking dog clutches) and conventional wet clutches. Simulation models for the torque converter, lock-up clutch, transmission gear train, interlocking dog clutches, wet clutches, hydraulic control valves and circuits were developed and integrated with a 1-D vehicle road load model. The integrated powertrain system model was calibrated using measurements from real-world driving conditions. Unknown model parameters, such as clutch pack clearances, compliances, hydraulic orifice diameters and clutch preloads were estimated and calibrated. Simulation results
Tractor hitch control system is used for attaching and operating various Agricultural Implements and for operating tipping trailer. The system has also got provision to attach additional Aux valves for rear and front mounted attachments. The rear mounted implements are coupled to the tractor using Three Point Linkage (3PL) System. The hitch hydraulics system consists of hydraulic pump, filter, piping’s, fittings and hydraulics lift unit. Hydraulics lift unit consists of a proportional control valve, cylinder, piston and power linkages. Conventional control valve is hydro mechanical part operated by mechanical linkages. The control valve and linkages plays major role in performance of hydraulics system. Hydraulics is required to operate in extreme conditions of soils such as very soft like sand to very hard like black cotton sand. These two extreme conditions makes linkage and control valve optimization work very challenging and very difficult to get single solution for soft and hard
The use of hybrid, fuel cell electric, and pure electric vehicles is on the increase as part of measures to help reduce exhaust gas emissions and to help resolve energy issues. These vehicles use regenerative-friction brake coordination technology, which requires a braking system that can accurately control the hydraulic brakes in response to small changes in regenerative braking. At the same time, the spread of collision avoidance support technology is progressing at a rapid pace along with a growing awareness of vehicle safety. This technology requires braking systems that can apply a large braking force in a short time. Although brake systems that have both accurate hydraulic control and large braking force have been developed in the past, simplification is required to promote further adoption. This paper describes the following three items: (1) an examination of the brake system functions that realize the regenerative-friction brake coordination and collision avoidance support
With the development of vehicle electrification, electronic hydraulic brake system is gradually applied. Many companies have introduced products related to integrated electronic hydraulic brake system (I-EHB). In this paper, an I-EHB system is introduced, which uses the motor to drive the reduction mechanism as a power source for braking. The reduction mechanism is composed of a turbine, a worm, a gear and a rack. A control method based on command feed-forward is proposed to improve the hydraulic pressure control of I-EHB. Based on previous research, we simplify the system to first order system, and the theoretical design of the command feed-forward compensator is carried out. The feed-forward controller is applied, including the velocity feed-forward and the acceleration feed-forward, to improve the response speed and tracking effect of the system. Then, related experiments were carried out on test bench to track three different types of target signal (different amplitude and
With the electrification and intelligentialization of vehicle, requirements on more intelligent and integrated brake system are put forward. A novel integrated-electro-hydraulic brake system (I-EHB) for automotive is presented to fulfill these requirements. I-EHB is consisted of active power source (APS), pedal feel emulator (PFE), electro control unit (ECU) and hydraulic control unit (HCU). The system characteristics of I-EHB are tested through test rig. According to characteristics experiments, friction and non-linear phenomena in hydraulic pressure control are found. In order to overcome these phenomena in control of I-EHB, chatter-compensation is adopted based on experiment analysis. Algorithm are tested and optimized through test rig. As a result, through chatter-compensation the hydraulic pressure is controlled accurately and chatter-compensation is optimized for different working conditions.
During the vehicle braking, the Regenerative braking system (RBS) transforms the kinetic energy into electric power, storing it in the power sources. To secure the baking process, it is required to use hydraulic braking pressure to coordinately compensate the regenerative braking pressure. The traditional hydraulic pressure control algorithm which is used in regenerative braking system coordinated control has obvious laddering effect in braking. Unit control cycle pressure deviations seriously affect the comfort and the braking feeling on the vehicle. In order to ensure the accurate implementation of the brake pressure on the wheel cylinder, according to the hardware configuration of regenerative braking system, this paper analyzes the active pressurization state of RBS during braking, acquires the overflow characteristics of the switch valve in ESP hydraulic control unit by designing of high frequency characteristic test experiment, the control range of valve core displacement in the
High speed on-off valve is applied widely in vehicle control systems. When high speed on-off valve is controlled by Pulse Width Modulation (PWM) of high frequency, the valve core can float at a certain position which is adjusted by changing the duty ratio within a certain effective range. Then the high speed on-off valve can control the flow and pressure linearly like proportional valve. Thus it is essential to extend the effective range of duty ratio to improve the linear control performance of high speed on-off valve. In this paper, the high speed on-off valve of the automotive Electronic Stability Program (ESP) is the focus, and its flow force is analyzed in detail to get the effects of hydraulic parameters on the valve performance. The mathematic model of the high speed on-off valve is derived. Then the valve structural parameters are optimized according to the Genetic Algorithm(GA), offering the theoretical references for extending the effective duty ratio of PWM. Besides, the
The permanent-magnet DC motor, which is directly connected to the hydraulic pump, is a significant component of hydraulic control unit (HCU) in an anti-lock braking system (ABS). It drives the pump to dump the brake fluid from the low-pressure accumulator back to master cylinder and makes sure the pressure decreases of wheel cylinder in ABS control. Obviously, the motor should run fast enough to provide sufficient power and prevent the low-pressure accumulator from fully charging. However, the pump don't need always run at full speed for the consideration of energy conservation and noise reduction. Therefore, it is necessary to accurately regulate the speed of the DC motor in order to improve quality of ABS control. In this paper, an accurate speed control algorithm was developed for the permanent-magnet DC motor of the ABS to implement the performance of the system, reduce the noise and save the energy in the meanwhile. Firstly, the hydraulic brake system and the DC motor models of
This SAE Aerospace Information Report (AIR) has been prepared to provide information regarding options for optical control of fluid power actuation devices. It is not intended to establish standards for optical fluid power control, but rather is intended to provide a baseline or foundation from which standards can be developed. It presents and discusses approaches for command and communication with the actuation device via electro-optic means. The development of standards will require industry wide participation and cooperation to ensure interface commonality, reliability, and early reduction to practice. To facilitate such participation, this document provides potential users of the technology a balanced consensus on its present state of development, the prospects for demonstration of production readiness, and a discussion of problem areas within this technology. The intent is to inform the user/designer of the options available for interfacing photonics (optics) to hydraulic power
This SAE Aerospace Recommended Practice (ARP) provides guidance for the design and installation of a commercial aircraft hydraulic system to meet the applicable requirements, including the applicable airworthiness regulations that affect the hydraulic system design. This ARP also provides information and guidelines on the many factors that arise in the design process to provide cost effectiveness, reliability, maintainability and accepted design and installation practices.
Modern on-road vehicles have been making steady strides when it comes to employing technological advances featuring active safety systems. However, off-highway machines are lagging in this area and are in dire need for modernization. One chassis system that has been receiving much attention in the automotive field is the steering system, where several electric and electrohydraulic steering architectures have been implemented and steer-by-wire technologies are under current research and development activities. On the other hand, off-highway articulated steering vehicles have not adequately evolved to meet the needs of Original Equipment Manufacturers (OEM) as well as their end customers. Present-day hydrostatic steering systems are plagued with poor energy efficiency due to valve throttling losses and are considered passive systems relative to safety, adjustability, and comfort. This paper introduces a novel scheme of an electro-hydraulic power steering system that utilizes a proven
This SAE Standard sets forth the instrumentation and procedure to be used in measuring sound pressure levels at the operator position for self-propelled off-road work machines as defined in SAE J1116. This document does not address the operation of safety devices such as backup alarms, horns, or accessories. This SAE document is applicable to machines that have operator stations where the operator can either stand or sit and will be either transported by, or walk with the machine during its operation. The sound levels obtained using this procedure are repeatable and representative of the higher range of sound levels generated by machines under actual field operating conditions. Due to variability of field operating conditions, this data is not intended to be used for operator noise exposure evaluations.
This SAE Standard sets forth the instrumentation and procedure to be used in measuring the exterior sound pressure levels for self-propelled off-road work machines as defined in sections 1, 3, 5 and 6 of SAE J1116. This document does not address the operation of safety devices such as backup alarms, horns, or accessories. The sound levels obtained by using the test procedures set forth in this document are repeatable and are representative of the higher range of sound levels generated by machines under actual field operating conditions. Due to the variability of field operating conditions, this data is not intended to be used for construction site boundary noise evaluations.
This SAE Recommended Practice provides the designer with guidance for the selection of directional control valves for use in the hydraulic systems of surface ships and submersibles. This guidance includes use of standard valves and interfaces, minimum envelopes that should be reserved to permit interchangeability, environmental considerations, and general technical requirements.
Items per page:
50
1 – 50 of 187