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Viewing 1 to 30 of 998
2013-09-24
Technical Paper
2013-01-2427
Lorenzo Serrao, Giulio Ornella, Gilberto Burgio, Ettore Cosoli
The paper illustrates the development of a hydraulic hybrid powertrain concept for off-highway vehicles, which is the result of a three-year program at Dana's advanced technology centers. Engineers have conducted extensive simulations and tests while equipping a demonstration vehicle to determine feasibility, develop advanced features, and quantify benefits of hydraulic hybridization for traction. The system concept and operation as well as its development process are illustrated, focusing the system engineering principles and on the model-based approach to system design, control, and energy analysis. Experimental results are provided.
2013-09-24
Technical Paper
2013-01-2352
Paul C. Niglas
The new RSDII (Reduced Stopping Distance, phase 2) regulation creates an increased emphasis by the heavy truck industry to ensure that brake systems are properly chosen and optimized. This regulation has led to vehicles being fitted with much more powerful brakes. However, despite the intent of these new brakes to provide larger braking forces for shorter stopping distances, the performance of vehicles is still limited by the maximum friction coefficient between the vehicle's tires and the road. In order to get the most out of these new brakes, it is essential that the entirety of the vehicle be taken into account. With the use of a hardware-in-the-loop simulation tool, this paper will present stopping data predictions from a variety of vehicles of varying brake torque and wheelbase. It will be shown how these factors change the way a vehicle behaves under panicked stopping situations.
2013-09-24
Technical Paper
2013-01-2349
Naseem A. Daher, Monika Ivantysynova
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.
2013-09-24
Technical Paper
2013-01-2347
Mikko Huova, Matti Linjama, Kalevi Huhtala
Hydraulic systems are widely used in working actions of mobile machines. They offer good power to weight ratio, robustness and relatively good controllability. However, there has been growing interest on the energy efficiency of such machines during recent years. Load sensing proportional valve control is a typical solution for multi-actuator systems leaving a significant margin for improvement of energy efficiency. Digital hydraulic valve system enables independent metering and reduces losses significantly without a need of complete redesign of the hydraulic system of such machine. Digital hydraulic valve system consists of parallel connected on/off-valves and offers deterministic operation which is crucial for successful implementation of independent metering. Four different digital hydraulic valve control approaches are analyzed in the paper: four-edge-control, four-edge control with pressurized tank line, five-edge-control and six-edge-controlled three-chamber-cylinder.
2004-10-26
Technical Paper
2004-01-2733
William P. Fornof
A coalescing filter is typically used in a compressed air system to remove liquid and oil aerosols. A coalescing filter is most efficient when located downstream of an air dryer. The air dryer removes most of the liquid oil condensed in the compressor discharge line. Measuring the percent of oil removed by a coalescing filter is useful for determining efficiency. This paper covers a laboratory method to reproduce oil aerosols much like the filter will see in an actual application. High duty cycles produce the maximum amount of oil from the compressor. The air dryer acts as pre-filter for the coalescing filter. The coalescing filter element and its associated housing should be tested as a unit since the element's inherent efficiency is effected by the design of the housing.
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.
2011-09-13
Journal Article
2011-01-2272
Wolfgang Schweiger, Werner Schoefmann, Andrea Vacca
This paper presents a simulation model for the analysis of internal gear ring pumps. The model follows a multi domain simulation approach comprising sub-models for parametric geometry generation, fluid dynamic simulation, numerical calculation of characteristic geometry data and CAD/FEM integration. The sub-models are interacting in different domains and relevant design and simulation parameters are accessible in a central, easy to handle graphical user interface. The potentials of the described tool are represented by simulation results for both steady state and transient pump operating conditions and by their correlation with measured data. Although the presented approach is suitable to all applications of gear ring pumps, a particular focus is given to hydraulic actuation systems used in automotive drivetrain applications.
1999-09-14
Technical Paper
1999-01-2811
Craig R. Eike, Guy T. Stoever
This paper will discuss the new Case MX Magnum® tractor transmission controls. They are electronically controlled, hydraulic valves that reduce transmission internal torque spikes, operator shift shock, complexity, and eliminated the need for periodic system calibration. The new system splits the controls into their simplest common denominators, and leverages commonality of parts and concepts to reduce both system and development costs. It maintains clutch pressure during low regulated pressure transients that occur during a shift, while compensating for clutch wear, to maintain the desired shift characteristics.
2011-09-11
Technical Paper
2011-24-0073
Enrico Chiappini
In the recent years, a new interest on kinetic energy recovery (KER) of vehicles arose. In USA, car manufacturers (Ford, Sheep et al.) developed research programs on the use of hydraulic devices to realize KER system, also with economical support of government body (EPA). In 2002 Ford built a very interesting prototype (Ford Tonka) using such recovery device (named HLA, Hydraulic Launch Assist), achieving very interesting improvements of fuel economy and pollution, besides increasing of acceleration and making feasible downsizing of thermal engine. Nowadays, also D.I.M.E.G. of University of L'Aquila (Italy) is working about HLA systems and, in order to study its behaviour, a simulation model (named V&HLA-SC) particularly useful to evaluate its energetic efficiency and performance has developed.
2005-04-11
Technical Paper
2005-01-0930
Bryon J. Sohns, Jeffrey L. Stein, Loucas S. Louca
Vital to the effectiveness of simulation-based design is having a model of known quality of the system being designed. The purpose of this paper is to validate a simplified dynamic model of an FMTV (Family of Medium Tactical Vehicles) for a range of system parameters using a previously developed technique for determining model robustness and accuracy within a design space. The literature provides an algorithm called AVASIM (Accuracy and Validity Algorithm for Simulation) for assessing model validity systematically and quantitatively. AVASIM assess the validity of a model based on a specific input and set of system parameters. The literature also defines a procedure for evaluating the robustness and accuracy of a model with respect to input and system parameter variations based on the AVASIM algorithm.
2004-11-16
Technical Paper
2004-01-3252
Paulo Cesar Momisso, Marcio Capati Talavera, Wagner Matos Santos, Helcio Onusic
SUMMARY When a new commercial vehicle project begins or some changes are necessary in the current products, the development of clutch pedals has a strong dependence with the powertrain characteristics which generally affects the clutch behavior and its actuation system. Although theoretical analyses are always taken into consideration, experimental procedures in bench tests and vehicles play an important role in the determination of new configurations for the clutch actuation system. Nowadays cost reduction, unification and quality gains must be considered in the project and development process. The above considerations mean that the work in bench tests regarding clutch actuation systems must be emphasized to simulate their behavior in the vehicle.
2004-10-26
Technical Paper
2004-01-2618
M. Borghi, M. Milani, F. Paltrinieri
This paper studies the influence of the discharge chamber geometrical parameters on the steady-state characteristics behavior of a conical seat valve having compensating profile. More in details, starting from the analysis of the experimental behavior of an actual valve showing inefficient characteristic curves, the metering openings leading to the transition from under to over compensation are individuated. Then, a 3D CFD steady-state, incompressible and isothermal analysis is involved, mainly to evidence the valve discharge coefficient and flow-forces variations with operating conditions. After, two alternative valve configurations, presenting a low pressure region designed to optimize the flow-forces compensation, are characterized through the 3D CFD analysis.
2012-09-24
Technical Paper
2012-01-2038
Alexandra Doan, James Yarosz, Zoran Filipi, Albert Shih
This paper investigates the development of a deaeration device to remove nitrogen from the hydraulic fluid in hydraulic hybrid vehicles (HHVs). HHVs, which use accumulators to store and recycle energy, can significantly reduce vehicle emissions in urban delivery vehicles. In accumulators, nitrogen behind a piston cylinder or inside a bladder pressurizes an incompressible fluid. The permeation of the nitrogen through the rubber bladder into the hydraulic fluid limits the efficiency and reliability of the HHV system, since the pressure drop in the hydraulic fluid can in turn cause cavitation on pump components and excessive noise in the system. The nitrogen bubbles within the hydraulic fluid may be removed through the employment of commercial bubble eliminators if the bubbles are larger than a certain threshold. However, gas is also dissolved within the hydraulic fluid; therefore, novel design is necessary for effective deaeration in the fluid HHV circuit.
2012-09-24
Technical Paper
2012-01-2040
Gabriele Altare, Damiano Padovani, Nicola Nervegna
The paper addresses some aspects of an ongoing research on a commercial compact excavator. The interest is focused on the analysis and modelling of the whole hydraulic circuit that, beside a load sensing variable displacement pump, features a stack of nine proportional directional control valves modules of which seven are of the load sensing type. Loads being sensed are the boom swing, boom, stick and bucket, right and left track motors and work tools; instead, the blade and the turret swing users do not contribute to the load sensing signal. Of specific interest are the peculiarities that were observed in the stack. In fact, to develop an accurate AMESim modelling, the stack was dismantled and all modules analysed and represented in a CAD environment as 3D parts. The load sensing flow generation unit was replaced on the vehicle by another one whose analysis and modelling have been developed using available design and experimental data.
2012-09-24
Technical Paper
2012-01-2042
Paolo Casoli, Alvin Anthony, Luca Ricco
This paper describes the results of a study focused on the mathematical modeling of an excavator hydraulic system. From the viewpoint of designing and tuning an efficient control system, the excavator is a very complex nonlinear plant. To design and tune such a complex control system an extremely good nonlinear model of the plant is necessary. The problem of modeling an excavator is considered in this paper; a nonlinear mathematical model of an excavator has been developed using the AMESim® modeling environment to replicate actual operating conditions. The excavator model is described by detailed models of the main pump, valve block and kinematic model. The objective of this research is to develop a complete simulation model of an excavator with the capability of reproducing the actual characteristics of the system. The model could then be used as a platform to facilitate the study of alternate control strategies towards energy efficient systems and new controller designs for HIL.
2016-09-27
Technical Paper
2016-01-8085
Yanjun Ren, Gangfeng Tan, Kangping Ji, Li Zhou, Ruobing Zhan
Abstract The hydraulic retarder is an auxiliary braking device generally equipped on commercial vehicles. Its oil temperature change influences the brake performance of hydraulic retarder. The Organic Rankine Cycle (ORC) is a good means to recover exhausted heat. Moreover, it can cool oil and stably control oil temperature with the help of heat absorption related with evaporation. Comprehensively considering the heat-producing characteristics of hydraulic retarder and the temperature control demand, the aimed boundary conditions are determined. Also the changing rules about the working medium flow rate are obtained. In this work, the heat-producing properties of hydraulic retarder under different conditions and the oil external circulating performance is firstly analyzed. By researching the system’s adaptation to the limiting conditions, the aimed temperature to control is prescribed.
2017-01-10
Technical Paper
2017-26-0373
Jatinkumar Janshali, G R M Rao
Abstract Close loop motion control implementation for electro hydraulic system with multistage telescopic cylinder aimed to articulate heavy load to desired angle while keeping acceleration, velocity of load and time to reach the desired angle within acceptable limit possesses stringent control system strategies. Conventional PID (Proportional-Integral-Derivative) control algorithm cannot be applied directly to control the system as these algorithms are also required to meet various other criteria apart from just to stabilize the system around the set point. In case of fail to meet these criteria can cause the damage to the components of subjected system and lead to disaster in worst case scenario. This paper describes the model based design approach to implement smooth motion control for heavy duty systems.
2017-01-10
Technical Paper
2017-26-0235
Vinaykumar Dhangar, Solairaj Perumal, Abhay Kumar, Dinesh Redkar, Arun Mahajan, Abhirup Chakraborty, T Ganesan
Abstract A tractor is vehicle specifically designed to deliver a high tractive effort at slow speeds for carrying out various agriculture operations like ploughing, rotavation etc. using implement. Hydraulic system is a key feature which connects these implements with the tractor. It controls the position and draft of the implement depending upon the type of crop, farming stage, implement type and soil conditions. These variations induces extreme range of load on the hydraulic system, thus making it challenging to design these components. Bell crank assembly is one of the main components of hydraulic system which controls the draft (thus, the loads experienced by tractor) through load sensing mechanism. Often bell crank assembly failures are reported from field due to uneven soil hardness and presence of rocks. This paper studies one of such bell crank assembly failures in the field. The failure was reported after half life cycle of usage during agriculture Operation.
2015-04-14
Technical Paper
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
Abstract The hydraulic retarder is an important auxiliary braking device for the heavy vehicle, which has some characteristics, such as the big brake torque and long duration braking, when the vehicle is traveling in braking state. However, the transmission power loss will be produced when the vehicle is traveling in non-braking state. This transmission power loss is called Air-friction. Firstly, the air flow distribution characteristics of retarder cavity are studied by computational fluid mechanics, and the Air-friction characteristic in different conditions is analyzed. Then, according to the Air-friction characteristics for the condition of different filling density, a set of vacuum air loss reduction system is designed. Meanwhile, the test bench for retarder Air-friction is set up, the test data of the revolution speed, pressure in cavity and air loss resistance is obtained according to the test bench for hydraulic retarder.
2015-09-29
Technical Paper
2015-01-2851
Aleksandar Egelja, Darren Allan Blum, Kalpesh N. Patel
Abstract Many off-highway machines, including hydraulic excavators, perform cyclical motion in their everyday activities where there is significant acceleration, deceleration, load lifting and hydraulic implement lowering. During that time in conventional off-highway machinery, most of the potential or kinetic energy is dissipated as heat instead of being captured and reused. When these opportunities are well understood and consequently machine systems are designed and integrated properly, fuel efficiency improvements could reach double digit values. It should be noted that the mentioned machine efficiency improvements will still vary depending on the machine size, its application and the characteristics of machine system(s) being applied. An approach for excavator energy flow analysis, coupled with rapid machine control design changes directed to minimization of energy losses is discussed.
2015-04-14
Technical Paper
2015-01-1373
Yulong Lei, Hui Tang, Xingjun Hu, Ge Lin, Bin Song
Abstract With the continuous improvement of the road condition, commercial vehicles get to be faster and more overloaded than before, which puts higher pressure on the vehicle braking system. Conventional friction braking has been difficult to meet the needs of high-power commercial vehicle. The auxiliary braking equipment will become the future trend for commercial vehicle. Hydraulic retarder is superior to secondary braking equipment. Previously hydraulic retarder research mainly focus on flow field analysis, the braking torque calculation, cascade system optimization and control methods for hydraulic retarder. The gas-liquid two-phase flow in working chamber is less researched. Based on this, this article discusses on the hydraulic retarder from two aspects. Firstly, this paper presents a block modeling method for hydraulic retarder system.
2015-09-29
Technical Paper
2015-01-2725
Amine Nhila, Daniel E. Williams
Abstract Today's hydraulic steering systems suffer from poor efficiency due to their use of throttling valves to build pressure inside the steering gear. In this work, we propose a novel way to build and control pressure by controlling the flow from the pump and without throttling. As a result, such a system will be more energy efficient. Moreover, the ability to control pressure inside a steering gear, and thus assistance torque, allows the steering system to become an active closed-loop system rather than a passive open-loop system. Specifically, by controlling pressure, one can closely control the hand wheel torque the operator feels. Consequently, the new pressure control concept has the potential to not only significantly improve the efficiency of steering systems, but also offers the numerous benefits of torque overlay without the use of an electric motor.
2015-09-29
Technical Paper
2015-01-2761
Boris Belousov, Tatiana I. Ksenevich, Sergei Naumov, Vitalii Stepnov, Anna Klimachkova
An electro-hydraulic servo system makes the basis for a mechatronic locomotion module (LM) and for a complex comprising an LM and an undercarriage of a vehicle. The servo system of the wheel module/LM complex is a combination of the information and power channels of the electro-hydraulic wheel drive within the steering system. A combination of the servo systems makes up a complex of servo systems of the steering system of the multi axis wheel mover of the vehicle. Theoretical and experimental studies of the functioning all-wheel steering were aimed on substantiation the rational algorithmic maintenance of the automatic control system. The results of the study allowed formulating the basic principles of designing and calculating the functionality algorithms for the steering system of the complex of mechatronic modules of the multi-axis vehicle.
2015-09-29
Technical Paper
2015-01-2872
Massimiliano Ruggeri, Andrea Cervesato, Carlo Ferraresi
Abstract Performance requests and machine automation, in conjunction with new regulations for commercial and heavy duty vehicles, represent a difficult challenge for machine design. Machine control systems complexity and functional safety regulation, are complex requirements to deal with in new machines design. The paper describes a steering system design, of a 6 wheeled agricultural front articulated self-propelled machine, that must comply with new regulations in terms of functional safety. The vehicle steering is driven by an electro-hydraulic system, totally controlled using electronics; the rear wheels are independently steered and controlled. This architecture requires a highly functional safety performance level. The safety analysis of the system lead to a required performance level whose compliance is a challenging task, due to the software quality required, and to the cost of a fully redundant hardware, on both electronics and hydraulics side.
2015-09-29
Technical Paper
2015-01-2854
Timothy Opperwall, Andrea Vacca
Abstract This work contributes to the overall goal of identifying and reducing noise sources and propagation in hydraulic systems. This is a general problem and a primary design concern for all fluid power applications. The need for new methods for identification of noise sources and transmission is evident in order to direct future modeling and experimental efforts aimed at reducing noise emissions of current fluid power machines. In this paper, this goal is accomplished through the formulation of noise functions used to identify contributions and transfer paths from different components of the system. An experimental method for noise transfer path analysis was developed and tested on a simple hydraulic system composed of a reference external gear pump, attached lines, and loading valve. Pressure oscillations in the working fluid are measured at the outlet of the pump. Surface vibrations are measured at multiple locations on the pump and connected system.
2015-09-29
Technical Paper
2015-01-2852
Daniel Ribeiro, Rodrigo Chaves, Rogerio Curty Dias, Gian Marques
Abstract In order to evaluate the opportunities to use hybrid concepts for heavy commercial vehicles for emerging markets, MAN Latin America has developed a VW refuse truck with 23t GVW using the hybrid hydraulic technology. The in site vehicle tests measurements has indicated a fuel savings up to 25%, which means a reduction around 4.08 liters of diesel/hour or 20 tones CO2/year [1]. Thus, a collaborative cooperation with Rio de Janeiro Sanitation Department (Comlurb) was set for a truck evaluation on a real operation. This 3-month evaluation used one VW 24.280 6×2 hybrid hydraulic refuse truck and other VW refuse truck similar standard diesel. A random dispatch system ensures the vehicles were used in a similar manner. Global positioning system logging, fueling, and maintenance records were used to evaluate the performance of this hybrid hydraulic refuse truck.
2015-09-29
Technical Paper
2015-01-2856
Hongbin Wang, Ojas Patil, QingHui Yuan, Aaron Hertzel Jagoda
EXTENDED ABSTRACT Fuel economy of both highway and off-highway vehicles is a major driver for new technology development. One of the technologies to meet this driver is a digital valve based hydraulic system. Digital Hydraulics technology employs high speed on/off valves to achieve the same functionality with no throttling loss. Furthermore, by forming various architecture by using digital valves, it provides the system level capability and flexibility for energy saving and productivity improvement. There are many challenges in fully realizing the full efficiency benefits of the system in an actual application. These challenges include packaging, durability, a change in the operator's perception of the vehicle as well as hydraulic system performances during operation. One significant issue is the noise, vibration and harshness (NVH) of the system. Due to the nature of the digital valve operation, there are severe transient dynamics in the fluid system.
2015-09-29
Technical Paper
2015-01-2855
Massimiliano Ruggeri, Giorgio Massarotti, Pietro Marani, Carlo Ferraresi
Abstract Losses reduction and oil flow optimization management in construction machines and, in general, in heavy duty vehicles are two of the most challenging missions of today fluid power research. One of the most promising ideas is to implement multiple hydraulic power sources but this requires a flexible pump switch system; in fact, depending on flow request and machine mode, one or more pumps can be switched to serve each actuator. To put into practice these concepts it is necessary to in-depth design the distribution system, through which hydrostatic transmissions supply the different loads. The new component here presented realizes the pump switch management, creating a matrix framework of the hydraulic flow connections. Putting this concept it into practice the new architecture is able to connect alternatively a pump to one actuator at a time providing also for cross connections, enabling different sources flow summation.
2016-09-27
Technical Paper
2016-01-8079
Zhiwei Zhang, Gangfeng Tan, Mengying Yang, Zhongjie Yang, Mengzuo Han
Abstract The hydraulic retarder is an important auxiliary braking device. With merits such as its high braking torque, smooth braking, low noise, long service life and small size, it is widely used on modern commercial vehicles. Transmission fluid of traditional hydraulic retarder is cooled by engine cooling system, which exhausts the heat directly and need additional energy consumption for the thermal management component. On account of the working characteristics of hydraulic retarder, this study designs a set of waste heat recovery system based on the Organic Rankine Cycle (ORC). Under the premise of ensuring stable performance of hydraulic retarder, waste heat energy in transmission fluid is recycled to supplement energy requirements for cooling system. First of all, a principle model, which is scaled down according to D300 retarder`s thermal power generation ration of 1:100, is established.
2016-09-27
Technical Paper
2016-01-8119
Jun Sun, Xiaofei Pei, Xuexun Guo, Yanqiang Zhao
Abstract In order to overcome hysteresis and dead zone problems caused by friction for the proportional solenoid valve, and improve rapidity and stability of the pneumatic system on hydraulic retarder, a closed-loop control strategy based on valve coil current was proposed. The high-frequency low-amplitude dither signal was introduced into the proportional solenoid valve. With the proper dither signal, the stick-slip motion of the valve core was transformed into a steady one, and its dynamic performance was improved. Consequently, response time of retarder was reduced during gear changing. The proportional valve coil current was measured as a feedback for a closed-loop control strategy. Combining with the closed-loop strategy, the PI control algorithm was adopted to make sure that valve current was in accordance with the target value. Pulse Width Modulation (PWM) signal was used for the driving of proportional solenoid valve.
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