Criteria

Text:
Sector:
Display:

Results

Viewing 1 to 30 of 1817
2011-04-12
Technical Paper
2011-01-0391
Quan Zheng, Bruce Church, Ken Defore
Electro-hydraulic actuation has been used widely in automatic transmission designs. With greater demand for premium shift quality of automatic transmissions, higher pressure control accuracy of the transmission electro-hydraulic control system has become one of the main factors for meeting this growing demand. This demand has been the driving force for the development of closed loop pressure controls technology. This paper presents the further research done based upon a previously developed closed loop system. The focus for this research is on the system requirements, such as solenoid driver selection and system latency handling. Both spin-stand and test vehicle setups are discussed in detail. Test results for various configurations are given.
2010-04-12
Technical Paper
2010-01-1200
Jyh-Shin Chen
Fully Flexible Valve Actuation (FFVA) systems provide maximum flexibility to adjust lift profiles of engine intake and exhaust valves. A research grade electro-hydraulic servo valve based FFVA system was designed to be used with an engine in a test cell to precisely follow desired lift profiles. Repetitive control was chosen as the control strategy. Crank angle instead of time is used to trigger execution to ensure repeatability. A single control is used for different engine speeds even though the period for one revolution changes with engine speeds. The paper also discusses lift profile extension, instantaneous lift profile switching capability and built-in safety features.
2004-03-08
Technical Paper
2004-01-1389
Liyun Zheng, Jeremy Plenzler
Vane type cam phasers have been widely used in internal combustion engines to vary valve timing to achieve purposes such as low emissions, greater torque, and higher horsepower. One of the primary concerns in using a vane phaser is its position holding ability when disturbances are present. Disturbances include cam torque oscillation, cam pulley speed fluctuation, oil pressure fluctuation, and engine acceleration or deceleration. Cam torque disturbance is the biggest contributor to phaser position error. This paper will first present the generic schematic of a variable cam phasing system and its challenges, followed by the characterization of the fluid dynamics of the vane phaser, with an emphasis on the effects of pressure, leakage, and oil aeration on the vane phaser fluid dynamics and its ability to reject cam torque disturbance.
2004-03-08
Technical Paper
2004-01-1031
Thomas C. Croft
A variety of factors require consideration throughout the seal selection process during the design of a hydraulic system. This work serves as a description of material and dimensional characteristics that should be utilized by design and maintenance engineers. Information is given regarding polymeric materials that are commonly used in the manufacture of sealing devices. For dimensional properties, equations and discussion are given to assist in determining the correct size and fit for seals. Practical information regarding failure analysis is presented as well.
2004-03-08
Technical Paper
2004-01-0835
J. Gholipour, M. J. Worswick, D. Oliveira
This paper examines the application of damage models in tube bending and subsequent hydroforming of AlMg3.5Mn aluminum alloy tubes. An in-house Gurson-based damage model, incorporated within LS-DYNA, has been used for the simulations. The applied damage model contains several void nucleation and growth parameters that must be determined for each material. A simpler straight tube hydroforming process was considered first to check the damage parameters and predicted ductility. Then the model was applied to a sequence of bending and hydroforming. The damage history from pre-bending was mapped to the hydroforming stage, to allow prediction of the overall ductility. The applied forming parameters in the simulation were based on data extracted during the experimental tests. Finally, the numerical results were compared to the experimental data.
2004-03-08
Technical Paper
2004-01-0847
Zi Lu, Philemon C. Chan
A test study of the sensitivity of airbag load at out-of-position (OOP) conditions was performed. The calibrated pneumatically driven Airbag Test Simulator (ATS) was used as the test platform to provide a large number of well-controlled repeat tests. Dummy responses were measured with parametric variations of dummy position, neck shield, airbag folding, airbag cover, and steering wheel effects. A selected airbag was used and tests were carried out using the Hybrid III and THOR dummies. The data were analyzed in detail to provide phenomenological understanding of the effects of some critical parameters affecting OOP loads and dummy responses. The results identify a number of critical parameters that can significantly affect dummy responses at OOP conditions.
2004-03-08
Technical Paper
2004-01-1322
A. J. Turner, K. Ramsay
With the drive toward more fuel efficient vehicles, the individual and combined efficiency of powertrain subsystems is increasingly important. Development of alternative transmission types (AMT, DCT, CVT) has brought significant benefits arising from an increase in the number of ratios, ratio span and unit efficiency. However, it is recognised that further potential lies in improving actuation technology in controlled transmissions, of all types. Since the economic benefit of further refinement of traditional hydraulic devices appears to be limited, it is suggested that alternative technology is required. This alternative would seek to further reduce parasitic energy consumption due to pumping and associated system losses and also improve poor duty cycle controllability, whilst enabling cooling of any slipping sub-elements.
2004-03-08
Technical Paper
2004-01-0652
Shingo Uozumi, Takao Taniguchi, Kazumasa Tsukamoto, Masahiro Hayabuchi, Tatsuya Iwatsuki, Satoru Kasuya
AISIN AW has developed a new six-speed automatic transmission TR-60SN for rear wheel drive (RWD) vehicles, for use in sports utility vehicles with high torque engines. This new TR-60SN has been developed based on the concept of improving fuel consumption and drivability while minimizing the number of component parts, and covering engine torque of 10 or 12 cylinders. To achieve this, TR-60SN utilizes component parts including gear train, torque converter, oil pump, and casing that have a completely new design. In addition, a new electric-hydraulic control unit has also been developed that offers both world class shift quality and a sporty shift feeling.
2004-03-08
Technical Paper
2004-01-0726
Patrick Tinchi Pang, David Agnew
The dynamic response time of a hydraulic brake system often comes into consideration when making decisions on system optimization or trade-offs in performance. A study of the relative importance of response time can be found in reference [1]. For the brake system engineer, it is desirable to know the impact that each of the system components contributes under varying conditions. To better describe and predict the fluid dynamics inside an automotive brake system, a model is set up to predict the pressure differential of the brake fluid through each brake component. A proposed method of testing in vehicle was used to quantify individual flow restrictions. The test results were compared to actual data for correlation. Knowing the individual flow characteristics of a brake systems components provides valuable information to the brake system engineer for the purpose of optimizing response time performance.
2004-03-08
Technical Paper
2004-01-1067
J. Z. Feng, F. Yu, Y. X. Zhao, G. Xu
In order to reduce the development time and cost of vehicle control systems, the co-simulation approach has been paid great attention recently, which combines the advantages of different software packages and provide the means of rapid iteration of control algorithm and insight into its effects on vehicle performance in design stage. This paper presents the design process of a controller for bandwidth-limited active hydro-pneumatic suspension employed by an off-road vehicle based on the co-simulation technology. First, a detailed multi-body dynamic model of the vehicle is established by using ADAMS/View software package. Second, aiming at achieving high ride quality and handling performance so as to increase the vehicle traveling speed even on rough terrain surfaces, a combined PID and fuzzy controller is designed for the bandwidth-limited active suspension system and then worked out by means of S-functions provided by Matlab/Simulink.
2004-10-25
Technical Paper
2004-01-3064
Hiroki Shimoyama, Shigeru Ikeo, Eitaro Koyabu, Ken Ichiryu, Suck-kyu Lee
In this study, we evaluate the effectiveness of the hybrid system using Constant Pressure Hydraulic System (CPS). In the city traffic, vehicles are required to start and stop frequently. Therefore, the engine often runs in its low efficiency area. So, we study the CPS hybrid vehicle. This paper shows the experimental and simulation results. The efficiency of this system depends on the performance of the hydraulic pump/motor. We investigate various methods to keep the operation of the pump/motor at the high performance point and compared the fuel economy with that of conventional vehicle.
2004-03-08
Technical Paper
2004-01-1386
J. W. G. Turner, M. D. Bassett, R. J. Pearson, G. Pitcher, K. J. Douglas
Electrohydraulic and electromechanical valve train technologies for four-stroke engines are emerging which allow much greater flexibility and control of the valve events than can be achieved using mechanically-based systems. Much of the work done on exploiting the benefits of these systems has been directed towards improving engine fuel economy and reducing emissions. In the present work a study has been made, using an engine simulation program, in to some of the possible benefits to engine performance that may be facilitated by the flexibility of fully variable valve train (FVVT) systems. The simulation study indicates that FVVT systems, limited by realistic opening and closing rates, provide sufficient range in the valve event duration and timing to enable the engine to produce very high specific outputs whilst achieving a high level of torque in the low- and mid-speed range.
2004-03-08
Technical Paper
2004-01-1638
Hiroshi Tsutsui, Takayuki Hisano, Akitomo Suzuki, Makoto Hijikata, Masatoshi Taguchi, Koichi Kojima
Recently, 5-speed automatic transmissions have become mainstream through the world, and 6-speed automatic transmissions have also been introduced in the market. Consequently, the issue of shift control is gaining importance, and a trend toward increasing number of gears in automatic transmissions has become apparent. On the other hand, weight saving and downsizing of the transmission, including the hydraulic control unit, are strongly required in order to promote fuel efficiency. To meet these requirements, an electro-hydraulic control unit offering sophisticated functionality desired in order to provide excellent shift quality. As an answer to these requirements AISIN AW developed two types of new 6-speed automatic transmissions in 2002: “TR-60SN” for RWD vehicles and “TF-60SN” for FWD vehicles. Both TR-60SN and TF-60SN have the same structural characteristics.
2004-03-08
Technical Paper
2004-01-1635
Hideaki Takahara, Hideki Yasue, Ryoji Habuchi, Tadashi Ishihara, Shigeo Tsuzuki, Jiro Maeda
As requirements for protecting the global environment are being heightened on a worldwide scale in recent years, the development of low fuel consumption technologies in order to inhibit the discharge of CO2 is an important issue for the automotive industry. Recently, Toyota has developed a Super CVT for the 1.3-to 1.5-liter class vehicles to further improve their fuel economy. This CVT has been adopted on vehicles equipped with the ‘idling stop system’. The ‘idling stop system’ automatically stops the engine when the vehicle is stopped and the transmission shift lever is in the ‘D’ position (e.g. when the vehicle is at a stoplight). This improves the fuel economy of the vehicle by eliminating fuel consumption while the vehicle is stopped. The conventional CVT poses unique conditions such as startoff time lag or shock after the engine is restarted. These conditions occur because the CVT oil pump cannot generate hydraulic pressure while the engine is stopped.
2004-03-08
Technical Paper
2004-01-1639
Cheolwan Kim, Chin-Yuan Perng, Dengfu Zhang
In this paper we describe the application of a CFD methodology to characterize the orifice flows over a wide range of flow conditions with various geometrical features commonly found in hydraulic control systems. There are three objectives in carrying out this study. First, apply CFD analyses to provide physical insight into the orifice flow physics and clarify the use of relevant engineering parameters critical to hydraulic control applications. Second, quantify orifice discharge coefficient with respect to orifice diameter ratio, cross-sectional shape, plate thickness, orifice entrance and exit geometries. Third, support physical test and establish building block elements for hydraulic system modeling. The results obtained from CFD calculations agree very well with available data published in professional handbooks and fluid mechanics related textbooks, especially in the high Reynolds number flow regime.
2013-01-09
Technical Paper
2013-26-0042
N. Prabhakar, P. Sripathy, S. E. Bharathiraja, K. Ayyappan
Leveling valves are typical pneumatic flow control valves which are fitted in the vehicle chassis to supply or deplete air pressure in the bellows so as to maintain the chassis always in a horizontal position, under the loaded or unloaded condition of vehicle or trailer. Therefore it is necessary to study the flow rate of air for different operating angles of leveling valve corresponding to the vehicle load. Filters are provided, one at the upstream and two at the downstream in order to prevent dust from entering into the valve and bellows. All flow control valves have an inherent flow characteristic that defines the relationship between ‘valve opening’ and flow rate under constant pressure conditions. Hence Computational Fluid Dynamics (CFD) can be utilized as a useful design tool to optimize the flow area of leveling valve and also to study the difference in pressure between upstream and downstream of a filter in order to push the fluid through the filters.
2013-01-09
Technical Paper
2013-26-0111
Parul Goyal, Gaurav Chaudhary, Nirmal N
A two-stage spool valve system is common in the hydraulic system of an off-road vehicle and used as hydraulics control element for controlling the hydraulic cylinder. Off-road vehicle industries mostly use a fixed-gain PID based controller for the flow control of the two-stage spool valve system. A hydraulic spool valve system exhibits highly nonlinear behavior, which makes it challenging to design a PID based controller to control its dynamics. This paper presents a method for the dynamic system model development of the two-stage spool valve system. This model will be useful to study the impact on the valve dynamics due to lubricating oil properties variation to avoid the potential system hazards and machine failure scenarios. An alternative control system design approach is also proposed based on the gain-scheduled control technique, wherein the non-linear dynamics of the valve system is linearized at different equilibrium points and PID gains are scheduled at these points.
2013-10-07
Technical Paper
2013-36-0498
Eduardo Sala Polati, Jan Vatavuk, Luiz A. Bloem da Silveira, Emerson Bertaglia de Paula
A damper and a gas spring being a thermo engine which vibrational energy absorption occurs over heat transformation, requires very specific properties of thermo chemical stability from the hydraulic fluid as well as shear strength by heat and pressure effect. It competes to the hydraulic fluid the task of this transformation vehicle. The absorption performance of a damper depends on variation of physical-chemical properties of the hydraulic fluid under heat effect and the maintenance of this performance depends on conservation of those properties during time. The traditional hydraulic fluids for this application, despite its thermo-chemical stability, suffer a deterioration process of those properties under severe operating conditions and consequently reflect in the damper component lifetime.
2011-05-17
Technical Paper
2011-01-1533
Nicholas Earnhart, Kenneth Marek, Kenneth Cunefare
Hydraulic systems pose a particular problem for noise control. Due to the high speed of sound in hydraulic fluids, components typically designed to reduce fluid-borne noise can easily exceed practical size constraints. This paper presents novel solutions to creating compact and effective noise control devices for fluid power systems. A hydraulic silencer is presented that utilizes a voided polymer lining in lieu of a pressurized bladder. Theoretical modeling is developed which predicts device performance and can assist in future design work. Experimental results are presented to demonstrate the performance of the device. Both voided and non-voided liners are tested to show the effect of the voiding on the performance. In addition, theoretical modeling and experimental results are presented for a prototype Helmholtz resonator that is two orders of magnitude smaller than previously developed devices.
2010-10-17
Technical Paper
2010-36-0507
Ricardo E. Musafir
Aeroacoustics aims at describing the generation of sound by fluid flow, a task which requires, in general, a somewhat arbitrary decision on what part of the flow is responsible for the sound generation process, which refers to propagation. Starting with Lighthill's analogy in the early 1950's, a number of models have been developed since. This paper reviews the modeling basics, with emphasis on the physics of the fluid dynamics/acoustic processes, discussing different acoustic analogies as well as its limitations. The discussion proceeds by comparing different models and solutions, notably, Ligthill's orginal formulation, Lilley's equation and its recent extension by Goldstein. Howe's analogy is also briefly commented. The context in which each model should be used is discussed, as is the question of the sensitivity of results to details of the modeling.
1999-09-28
Technical Paper
1999-01-3319
Takaaki Tsukui, Koji Tsutsumizaki, Mutsuo Nakajima
New valve control system (HYPER VTEC:Variable Valve Timing and Lift Electronic Control System) having valve inactive mechanism which engine power is made to be united to the environment conservation was developed for motorcycle engines of sport type having higher engine speed. Mass increase in the valve operating system of this system is kept to a minimum with a compact, simple mechanism. The system enables high engine speed up to 13,500 rpm without abnormal motion of valves, having high reliability and durability. In addition, the valve control system has the enhancement of fuel economy and the effect of decreasing the intake and exhaust system sound during 2-valve operation. The switching mechanism part of the operating valve number was manufactured by cold forging, and has decreased costs. This system has been adopted to the sport type motorcycle CB400SF for domestic model in 1999.
1999-10-25
Technical Paper
1999-01-3554
Jian Rong Qin, S. T. John Yu, Ming-Chia Lai
In this paper, we report direct calculations of cavitating pipe flows by the method of Space-Time Conservation Element and Solution Element, or the CE/SE method for short. The tenet of the CE/SE method is treating space and time as one entity, and the calculation of flow properties is based on the local and global space-time flux conservation. As a contrast to the modern upwind schemes, no Riemann solver is used, thus the logic of the present scheme for cavitating flows is much simpler. Two numerical examples are reported in this paper: (1) a hydraulic shock problem, and (2) a cavitating pipe flow. For the hydraulic shock problem, we demonstrate the capability of the CE/SE method for capturing contact discontinuities in cavitating fluids. For the pipe flows, a two-phase homogeneous equilibrium cavitation model is employed. In both cases, numerical results compared favorably with the experimental data and analytical solution.
2000-03-06
Technical Paper
2000-01-0822
Werner Harter, Wolfgang Pfeiffer, Peter Dominke, Gerhard Ruck, Peter Blessing
Additional future requirements for automobiles such as improved vehicle dynamics control, enhanced comfort, increased safety and compact packaging are met by modern electrical steering systems. Based on these requirements the new functionality is realized by various additional electrical components for measuring, signal processing and actuator control. However, the reliability of these new systems has to meet the standard of today's automotive steering products. To achieve the demands of the respective components (e.g. sensors, bus systems, electronic control units, power units, actuators) the systems have to be fault-tolerant and/or fail-silent. The realization of the derived safety structures requires both expertise and experience in design and mass production of safety relevant electrical systems. Beside system safety and system availability the redundant electrical systems also have to meet economic and market requirements.
2000-03-06
Technical Paper
2000-01-0811
Mohamad Qatu, David Llewellyn, Russell Edwards
Higher demands from automotive customers for quieter vehicles and the reduction of noise and vibration levels from major sources like the engine necessitate better performance of other sources of noise and vibrations in a vehicle. One of these sources that Original Equipment Manufacturers (OEM) demand making quieter is the power steering system. The pressure ripple generated by the power steering pump transfers to the fluid lines where it can generate objectionable noise and vibrations. This can become an excitation force to the structure of a vehicle or the steering gear and can become a source of discomfort to the vehicle occupants. Attenuation of the pressure ripple within the hose assembly can result in significant reduction in noise inside the vehicle. The NVH research team at the Fluid System Products of Dana Corporation has developed “Dana's Virtual Test Rig (DVTR™),” - a hydraulic system simulation software.
2000-03-06
Technical Paper
2000-01-0124
Andrew T. Bay
In the field of Electro-Hydraulic Automatic Control Valves, precise output pressure control is vital for proper shift performance of the automatic transmission. With smaller operating tolerances becoming more prevalent in the industry, test stand capability becomes vital to determining product improvements, yields, and performance. With the use of Computer Aided Engineering(CAE) simulation software, a test system can be simulated mathematically and capability can be studied and quantified.
1999-12-01
Technical Paper
1999-01-3068
Luiz Carlos Casado, Marli La Selva, José Roberto Lourenço, Roberto Antonio Moita, Agnaldo L. da Silva, Antonio Carlos V. Vaqueiro
1999-09-28
Technical Paper
1999-01-3158
K. Siegert, A. Schwager, R. Rieger, M. Häussermann
In cooperation with industrial companies at the Institute for Metal Forming Technology (IFU) of the University of Stuttgart, Germany, a new press concept specially for hydroforming tubes and extrusions was developed. The press has a capacity of 3500 tons closing force and a press table size of 2500 mm × 900 mm. A great reduction in costs can be achieved by integrating spacers between the frame of the press and the ram. This paper introduces this new press.
1999-08-17
Technical Paper
1999-01-2936
T. Fuseya, T. Nishimura, Y. Sato, H. Tanaka
A dynamic and hydraulic analysis on common-rail injectors using Bond Graph Simulation Program (BGSP) was made. BGSP is based on the Bond Graph method of hydraulic system modeling, which has an advantage in handling multi-energy domains such as common-rail fuel injection system. After the verification of BGSP, analysis was made on a few concepts of common-rail injectors. Pressure traces of the control chamber for each injector concept was obtained. Through these analysis, the key phenomena were identified. Although the optimization has not been done yet, compatibility between initial injection rate shaping and rapid closing on a common-rail fuel injector was discussed. As a result, common-rail injectors with a “variable inlet orifice” concept have better compatibility.
2000-03-06
Technical Paper
2000-01-0104
F. Gay, N. Coudert, I. Rifqi, Ph. de Larminat
This paper aims to present a control law for active suspension. The goal of active suspension system is to control the vehicle's body and more precisely to control heave, pitch and roll despite driver's and road perturbation. Nevertheless, a control law should also integrate other demanding such as robustness and capacity to filter road irregularities. The structure of the proposed control law suits these constraints and is based on a cooperation between feedforward and feedback. Feedforward design is based on the vehicle physics. The feedback law is synthesized with a new methodological approach, the Standard State Control (2SC) which enables the designer to focus on the crucial trade-off between performance and robustness even for multivariable law.
2000-03-06
Technical Paper
2000-01-0284
Felix Klingebiel, Uwe Kahlstorf
This paper describes the use of 1-D Fluid Flow Simulation Software Models of different complexity to model different aspects of Internal Combustion Engine Lubrication Systems. It shows how such models may differ in order to achieve the analysis objectives and reliable results for the different aspects of the system. It also shows how sub models can be used to compose system models which reflect the interaction of the engine's fluid systems.
Viewing 1 to 30 of 1817

Filter

  • Range:
    to:
  • Year: