The conventional car suspension system uses isolated shock absorbers that are only capable of dissipating energy in the form of heat. Each shock absorber in a hydraulic interconnected suspension is connected by hydraulic circuits, allowing the electrified hydraulic fluid to be used to counteract undesirable body motion and enhance dynamic performance as a whole. An established idea with good potential for managing body rolling and separating the warp mode from other dynamic modes is the hydraulic interconnected suspension. While certain active or semi-active suspension technologies enable the shock absorbers to compensate for the effects of the road disturbances using external power input, hydraulic linked suspension is still passive and lacks adaptivity. In order to adjust the suspension's damping properties to rapidly changing road conditions, active suspensions, like electromagnetic shock absorbers, utilize the magnetofluid's variable viscosity. In some circumstances, the energy requirement of an active suspension might amount to kilowatts, which lowers the vehicle's fuel efficiency. This research proposes a novel energy-harvesting hydraulically interconnected shock absorber (EH-HISA) system to find a balanced solution to dynamic performance and energy efficiency by incorporating energy harvesting ability to a passive hydraulically interconnected suspension. Improved energy efficiency and vehicle dynamics performance are provided by the features which combine energy harvesting with hydraulic interconnection. AMESim is used to build a single diagonal hydraulic circuit model, which is then validated in a bench test. The theoretical model's validity was established by the bench test results, and the model was then applied to estimate system performance. To verify the effectiveness of the entire system design, a full car model outfitted with EH-HISA is created. For model simulation, various dynamic input scenarios—including sinusoidal input and double lane change tests—are applied. The EH-HISA achieves average lateral acceleration improvements of 38% over traditional suspensions and 11% compared to a prior design (EHHIS proposed by Chen et al.) and average energy harvesting ability improvements of 133 % while maintaining acceptable anti-rolling dynamics in the double lane change test. The EH-HISA also improves the anti-rolling ability by 30 % as compared to traditional suspensions. The power generated is found to reach maximum of 210 W at 2 Hz and 20 mm sinusoidal input. Bench tests are performed on the EH-HISA prototype to validate the simulation results. Damping force and energy harvesting experimental data is measured and compared with the simulation results to validate the effectiveness of the system. / Master of Science / The vehicle industry has always sought improved road handling dynamics and riding comfort. The vehicle body may move in a variety of ways, including roll, pitch, and bounce; each of these motions can endanger passengers' safety and lead to passenger fatigue. Oil shock absorbers that are isolated from the rest of the vehicle's suspension system can only dissipate energy by forcing oil via dampening valves. A hydraulic interconnected suspension can connect each shock absorber using hydraulic circuits so that the energized hydraulic fluid can be used to reduce unwanted body motion and enhance the overall riding experience. A tried-and-true idea, the hydraulic interconnected suspension (HIS), has shown promising results in stabilizing the vehicle body on unsteady roads. While active suspensions, like electro-magnetic shock absorbers, can employ an external power source to compel them to adjust to rapidly changing road conditions, hydraulic linked suspension is still passive and unadaptive. In some circumstances, the energy requirement of an active suspension might amount to kilowatts, which lowers the vehicle's fuel efficiency. Additionally, there is always a chance that a system that is actively receiving power will malfunction as a result of a power outage. This research offers a new type of energy-harvesting hydraulically interconnected shock absorber (EH-HISA) system to achieve a balanced solution to dynamic performance and energy efficiency. The combined energy-harvesting and HIS system provide improved energy efficiency as well as vehicle dynamics performance. Each system is composed of two distinct diagonal hydraulic circuits which interconnect the shock absorbers of the diagonal wheels in a vehicle. AMESim is used to build a single diagonal hydraulic circuit model, which is then validated in experiments, as a starting point for investigating the effectiveness of the overall system. The theoretical model's validity was established by the outcomes of the bench tests, and the model was then utilized to predict system performance. A full car model is created based on the tested single diagonal hydraulic circuit model to assess the performance of the entire system architecture. Different road condition scenarios are used for model simulation, which includes sinusoidal input and double lane change test. The EH-HISA achieves average lateral acceleration improvements of 38% over traditional suspensions and 11% compared to a prior design (EHHIS proposed by Chen et al.) and average energy harvesting ability improvements of 133 % while maintaining acceptable anti-rolling dynamics in the double lane change test. The EH-HISA also improves the anti-rolling ability by 30 % as compared to traditional suspensions. The power generated is found to reach maximum of 210 W at 2 Hz and 20 mm sinusoidal input. Bench tests are performed on the EH-HISA prototype to validate the simulation results. Damping force and energy harvesting experimental data is measured and compared with the simulation results to validate the effectiveness of the system.

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The aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides strong limits on component weight and size, high safety and reliability standards demand simple solutions. Hence, basic silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the-art aboard commercial aircrafts. Unfortunately, they do not meet today’s noise attenuation aims regarding passenger comfort and equipment durability. Significant attenuation performance is expected from active concepts that generate anti-phase noise. However, such concepts remain a long term approach unless related costs, e.g. due to additional power allocation and real-time control equipment can be avoided. In this paper an active fluid borne noise attenuation concept is discussed that accounts for the mentioned constraints. An aircraft hydraulic pump is considered as main noise source. The active attenuator is an in-house rotary valve design. The basic feature is a known direct shaft coupling principle of pump and rotary valve, so no speed/ frequency control of the valve and no separate power supply are required. The common-shaft principle is further simplified here and proposed as integral feature of future “smart pumps”.

The modelling of multi-phase water flow is an important modern-day design tool used by engineers to develop practical systems which are beneficial to society . Multi-phase water flow can be found in many important industrial applications such as large scale conventional and nuclear power systems, heat transfer machinery, chemical process plants, and other important examples. Because of many inherent complexities in physical two-phase flow processes, no generalised system of equations has been formulated that can accurately describe the two-phase flow of water at all flow conditions and system geometries. This has led to the development of many different models for the simulation of two-phase flow at specific conditions. These models vary greatly in complexity. The simplest model that can be used to simulate two-phase flow is termed the homogeneous equilibrium (HEM) two-phase flow model. This model has been found useful in investigations of choking and flashing flows, and as an initial investigative model used before the formulation of more complex models for specific applications. This flow model is fully de ned by three conservation equations, one each for mass, momentum and energy. To close the model, an equation of state (EOS) is required to deliver system pressure values. When solving the HEM, a general practice is to employ an equation of state that is derived from a fundamental expression of the second law of thermodynamics. This methodology has been proven to deliver accurate results for two-phase system simulations. This study focused on an alternative formulation of the equation of state which was previously developed for the time dependent modelling of HEM two-phase flow systems, termed the rate form of the equation of state (RFES). The goal of the study was not to develop a new formulation of the EOS, but rather to implement the RFES in a transient simulation model and to verify that this implementation delivers appropriate results when compared to the conventional implementation methodology. This was done by formulating a transient pipe and reservoir network model with the HEM, and closing the model using both the RFES and a benchmark EOS known to deliver accurate system property values. The results of the transient model simulations were then compared to determine whether the RFES delivered the expected results. It was found that the RFES delivered sufficiently accurate results for a variety of system transients, pressure conditions and numerical integration factors. / MIng (Nuclear Engineering), North-West University, Potchefstroom Campus, 2014

The modelling of multi-phase water flow is an important modern-day design tool used by engineers to develop practical systems which are beneficial to society . Multi-phase water flow can be found in many important industrial applications such as large scale conventional and nuclear power systems, heat transfer machinery, chemical process plants, and other important examples. Because of many inherent complexities in physical two-phase flow processes, no generalised system of equations has been formulated that can accurately describe the two-phase flow of water at all flow conditions and system geometries. This has led to the development of many different models for the simulation of two-phase flow at specific conditions. These models vary greatly in complexity. The simplest model that can be used to simulate two-phase flow is termed the homogeneous equilibrium (HEM) two-phase flow model. This model has been found useful in investigations of choking and flashing flows, and as an initial investigative model used before the formulation of more complex models for specific applications. This flow model is fully de ned by three conservation equations, one each for mass, momentum and energy. To close the model, an equation of state (EOS) is required to deliver system pressure values. When solving the HEM, a general practice is to employ an equation of state that is derived from a fundamental expression of the second law of thermodynamics. This methodology has been proven to deliver accurate results for two-phase system simulations. This study focused on an alternative formulation of the equation of state which was previously developed for the time dependent modelling of HEM two-phase flow systems, termed the rate form of the equation of state (RFES). The goal of the study was not to develop a new formulation of the EOS, but rather to implement the RFES in a transient simulation model and to verify that this implementation delivers appropriate results when compared to the conventional implementation methodology. This was done by formulating a transient pipe and reservoir network model with the HEM, and closing the model using both the RFES and a benchmark EOS known to deliver accurate system property values. The results of the transient model simulations were then compared to determine whether the RFES delivered the expected results. It was found that the RFES delivered sufficiently accurate results for a variety of system transients, pressure conditions and numerical integration factors. / MIng (Nuclear Engineering), North-West University, Potchefstroom Campus, 2014

With the development of the transport, the traffic is more and more crowed. And another reason which is the price of the vehicle is cheaper. So much more people can buy the cars, thus, the road is more crowd, people should park their cars which need a lot of area, so we can see lots of parking lots in the city, but the classical parking system cannot reach the requirements nowadays. So, we should a new parking system. So, in this report, we will introduce a new parking lot and system, which includes the modelling, programming, material stress analysis and motors. At first, we reference the classical parking lots and some new parking lots. We find some problem about them which have not enough area and non-automated. Thus, we design a dimensional parking lot with programming. Which can realize automatic. Secondly, we use the inventor 2017 to build the model and analysis about stress concentration. We also use inventor to simulation the action about our parking lot. In the model, we use the hydraulic system to drive the lift, which can up and down to park the cars, and we create a new system to fix the wheels to make sure the cars cannot move in the movement procedure. Finally, our parking lot is an automatic and dimensional project. We will show you much more detail about our project, we hope our project will improve the parking lots to make people’s life better and convenient.

The automotive industry has been in a marathon of advancement over the past decades. This is partly due to global environmental concerns about increasing amount of air pollutants such as NOx (oxides of nitrogen), CO (carbon monoxide) and particulate matters (PM) and decreasing fossil fuel resources. Recently due to stringent emission regulations such as US EPA (Environmental Protection Agency) and CARB (California Air Resource Board), improvement in fuel economy and reduction in the exhaust gas emissions have become the two major challenges for engine manufacturers. To fulfill the requirements of these regulations, the IC engines including gasoline and diesel engines have experienced significant modifications during the past decades. Incorporating the fully flexible valvetrains in production IC engines is one of the several ways to improve the performance of these engines. The ultimate goal of this PhD thesis is to conduct feasibility study on development of a reliable fully flexible hydraulic valvetrain for automotive engines. Camless valvetrains such as electro-hydraulic, electro-mechanical and electro-pneumatic valve actuators have been developed and extensively studied by several engine component manufacturers and researchers. Unlike conventional camshaft driven systems and cam-based variable valve timing (VVT) techniques, these systems offer valve timings and lift control that are fully independent of crankshaft position and engine speed. These systems are key technical enablers for HCCI, 2/4 stroke-switching gasoline and air hybrid technologies, each of which is a high fuel efficiency technology. Although the flexibility of the camless valvetrains is limitless, they are generally more complex and expensive than cam-based systems and require more study on areas of reliability, fail safety, durability, repeatability and robustness. On the contrary, the cam-based variable valve timing systems are more reliable, durable, repeatable and robust but much less flexible and much more complex in design. In this research work, a new hydraulic variable valve actuation system (VVA) is proposed, designed, prototyped and tested. The proposed system consists of a two rotary spool valves each of which actuated either by a combination of engine crankshaft and a phase shifter or by a variable speed servo-motor. The proposed actuation system offers the same level of flexibility as camless valvetrains while its reliability, repeatability and robustness are comparable with cam driven systems. In this system, the engine valve opening and closing events can be advanced or retarded without any constraint as well as the final valve lift. Transition from regenerative braking or air motor mode to conventional mode in air hybrid engines can be easily realized using the proposed valvetrain. The proposed VVA system, as a stand-alone unit, is modeled, designed, prototyped and successfully tested. The mathematical model of the system is verified by the experimental data and used as a numerical test bench for evaluating the performance of the designed control systems. The system test setup is equipped with valve timing and lift controllers and it is tested to measure repeatability, flexibility and control precision of the valve actuation system. For fast and accurate engine valve lift control, a simplified dynamic model of the system (average model) is derived based on the energy and mass conservation principles. A discrete time sliding mode controller is designed based on the system average model and it is implemented and tested on the experimental setup. To improve the energy efficiency and robustness of the proposed valve actuator, the system design parameters are subjected to an optimization using the genetic algorithm method. Finally, an energy recovery system is proposed, designed and tested to reduce the hydraulic valvetrain power consumption. The presented study is only a small portion of the growing research in this area, and it is hoped that the results obtained here will lead to the realization of a more reliable, repeatable, and flexible engine valve system.

The theoretical stability analysis of mold level control system for slab continuous casting machine is presented in this thesis. In the procedure of analyzing the stability of the mold level control system, the PLC program written for the control system is studied first in order to obtain the mathematical model of a PID controller. Then the mathematical models of servo-amplifier, servo-valve, electro hydraulic system to the output of mold level are established. A simulative control system using Matlab software is constructed in accordance with these mathematical models so that not only the results of stability analysis can be verified but also the dynamic response of controlled system can be studied. Finally, the effects of some potential disturbance on system¡¦s dynamics, stability, and control accuracy are also analyzed.

Darbo apimtis yra 51 puslapių, jame yra 23 paveikslėliai. Literatūros aprašą sudaro 36 literatūros šaltiniai. Pagrindinis tiriamojo darbo tikslas – išanalizuoti hidraulinio cilindro stūmoklio greičio charakteristikų priklausomybę, keičiant hidraulinio cilindro apkrovą bei esant pastoviam siurblio slėgiui. Magistrantūros baigiamąjį darbą sudaro trys dalys: literatūros apžvalga, teoriniai tyrimai ir eksperimentiniai tyrimai. Literatūros apžvalgoje pateikiama droselinės hidraulinių sistemų reguliavimo sistemos, automatizuotos sistemos bei jų sandara. Teoriniuose tyrimuose yra išnagrinėtas droselinis valdymas ir reguliavimas, jo veikimo principai, naudingumo koeficientai bei galios balansas. Eksperimentiniuose tyrimuose yra išnagrinėta hidraulinio cilindro stūmoklio greičio charakteristikų priklausomybė nuo hidraulinio cilindro stūmoklio judėjimo greičio bei apkrovos. Sumontavus specialią hidraulinę sistemą atlikti hidraulinio cilindro stūmoklio greičio charakteristikų tyrimai. / Volume of work is 51 pages and contains 23 pictures. References inventory consists of 36 literary sources. The main aim of the investigation - to analyze the hydraulic cylinder shaft speed characteristics of dependency, changing the working pressure of hydraulic system and droseliavimo character. Master's thesis consists of three parts: an overview of sources of information, an overview of theoretical studies and experimental studies. Review of information sources describe butterfly hydraulic systems framework, addresses the butterfly speed control characteristics. The work purpose – to find out features of throttle adjustment of speed of movement the piston of hydraulic system of the big capacity. Experimental researches have been carried out with earlier described device. In the hydraulic cylinder design changes have been executed, the sizes and throttle place by means of theoretical throttle characteristic ADR = f(h) are changed. For reduction of turn time of a working platform it was necessary to increase pressure in hydraulic systems with 60 to 70 bar. Pressure increase has allowed piston to increase speed of movement. These changes have specified on a smooth stop of a working platform a problem. Time of turn of a working platform has decreased till 1,31 seconds. The piston pressure in the braking chamber is equal in last phase of work 48 bar, it tells about prevention of blow the piston about the hydraulic cylinder.