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Viewing 181 to 210 of 6706
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
2015-01-2855
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.
2015-09-29
Technical Paper
2015-01-2720
Sundarram Arunachalam, Ramprabhu Kannan, Jayaramareddy Sekar
Abstract Steering gear box function is one of the important requirements in heavy vehicles in order to reduce driver fatigue. Improper functioning of steering gear box not only increases the driver fatigue, also concerns the safety of the vehicle. In this present investigation, the engine oil mixing up with steering oil has been identified and steering gear box failure has been observed in the customer vehicle. The root cause of failure has been analyzed. Based on the investigations, in particular design of steering pump has been failed at customer end. The same design of steering pump were segregated and analyzed. Initial pressure mapping study has been conducted. The pressure mapping results revealed that the cavity pressure obstructs the flow of suction pressure. It indicates that obstacle at suction port due to the existence of internal leakage that causes back pressure in the internal cavity of steering pump which sucks engine oil.
2015-09-29
Technical Paper
2015-01-2791
Srinivas Anantharaman, Manoj Baskaran
Abstract Nozzles tip Temperature (NTT) of an injector is a critical parameter for an engine as far as reliability of engine is concerned. It is required to ensure that the injectors operate under its operational limit because higher operating temperatures would result in enlargement of the nozzle spray tip, resulting in higher through flow, producing more undesirable power. This could result in failure of other components in the engine. In this paper we identify the various parameters that are critical for NTT and thereby predict the NTT by having the known input parameters. Response surface methodology and artificial neural network are used to identify the parameters, estimate the significance of each parameter and predict the NTT. Based on this analysis, even without the use of an instrumented injector NTT can be predicted at various working conditions of the vehicle on different terrains.
2015-09-29
Technical Paper
2015-01-2730
Prasad S. Warwandkar, Naveen Sukumar, Preeti Gupta
Abstract Ever-increasing operational cost, reducing profit margins & increase in competition, it is of upmost significance for fleet owners & drivers to opt for a vehicle having maximum uptime. OEM's are under immense pressure to design & develop vehicles/subsystems which are reliable enough to minimize downtime & withstand heavy overloading plus extreme operating conditions especially tippers. Vehicle systems like Wheel end (hub, bearing, and grease) which are designed & packaged according to a very stringent envelop & operate as a closed system facing all the extremities of operating conditions. This undoubtly make them prone to no. of failure modes which are resulting in vehicle unplanned stoppages, so any failure mode related to the same must be taken care with utmost importance. In commercial vehicles the bearing outer cup is in interference fit with the hub. These bearings of wheel hub have to be maintained at the wheel end play of few microns.
2015-09-27
Journal Article
2015-01-2672
Aihong Meng, Jian Song
Abstract 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.
2015-09-22
Technical Paper
2015-36-0451
Marcos Rogério Sanches Barbetti, Aureo Jum Sibuya, Henrique Martelli, João Fernando M. Amparo
Abstract This Paper presents the “Frequency Sweep Virtual Analysis” as a tool to help to define the best powertrain mount concept in order to identify the resonance mode frequency on Powertrain System. Applying this method, we can identify proposals to reduce loads in the Powertrain system due the resonance mode and consequently minimize possibility of exceeding material strength. The “Frequency Sweep Virtual Analysis” drives the powertrain mounts design to avoid running many Road Load Data Acquisitions (RLDA) in a trial-and-error process (Cost reduction and timing savings).
2015-09-22
Technical Paper
2015-36-0557
S. F. Rigatto, C.B. Zanelato, F.A.F. Monhol
Abstract The hydrodynamic thrust bearings has been the subject of several studies in the scientific environment. In the hydrodynamic lubrication the surfaces are completely separated by the lubricating film, and therefore it is the most desirable type of lubrication. The lubricant should be chosen in order to reduce power losses by viscous dissipation. The work aims to analyze the power loss by viscous dissipation for various types of lubricating oils. It was investigated a six pivoted-pad thrust bearing in a rotation range between 1500 rpm and 3000 rpm. Eleven different types of lubricating oils were analyzed. It was possible to observe the net power loss - in function of the lubricant type - for each of the thrust bearings located in an automobile. The cost associated with this loss of potency was also obtained. The results showed that the appropriate selection of the lubricating generates an increase of 50% in power gain.
2015-09-22
Technical Paper
2015-36-0112
Fernando de Azevedo Silva, Erick Siqueira Guidi
Abstract The union of parts by using bolts is one of the most used, which combines versatility and low cost, and the failure of a single bolt can cause failure of the entire structure or machine. Several factors influence the effectiveness of these bolted joints, including the material of the washer. During the process of applying torque to the bolted joint, an elastic deformation occurs in the bolt and a plastic deformation in the washer while applying the external force. This plastic deformation which occurs in the washer causes a reduction of the elastic deformation of the bolt and, consequently, of the assembly torque, and depending on the values of external loading and deformation of the washer occurs the separation of the pieces of the joint, causing overload in the bolt and a reduction in your fatigue life. The use of numerical simulation using the finite element method makes it possible to change the model variables, such as the geometry and materials of the components.
2015-09-22
Technical Paper
2015-36-0141
Alisson Sarmento, André Luiz J. Pereira, Lincoln Lima, Luciana Rodrigues
Abstract The purpose of this paper is present a successfully application of Design For Assembly (DFA) and Design for Manufacturing (DFM) on Pickup-Box reinforcement. Those powerful quality tools are widely used during automotive design development and it might be a competitive design solution. As an introduction, a complete DFA and DFM revision is provided in order to allow methodology comprehension. Currently automakers technologies are shown as well. An introduction about product development process is presented in order to contextualize the DFA/DFM application in a real design situation. A rich and detailed revision about Pickup versions and body structure concept are covered as well. The study of case about DFA/DFM application on Mid-size Pickup-box Inner asm reinforcement generated 36-42% of mass reduction and 58-66% of cost reduction.
2015-09-22
Technical Paper
2015-36-0286
Lincoln Lima, Andre Pereira, Jose Lincoln Cavalcanti, Mauricio Kawano, Roberto Ferreira
Abstract In the vehicle development, part design has a huge influence in its mass, cost and performance. In addition, the part design can be helpful to solve some structure issues such as sheet metal cracks and boom noise, and at the same time achieving the project requirements in performance tests as crash, durability, noise and vibration (N&V) etc. Some design changes as adding reinforcements in the structure and increase the part thickness are largely used by the design engineers. On the other hand, these changes has a great potential for increase mass, cost and affect directly the fuel consumption, which are very sensitive factors for the OEM′s. In order to achieve its target some options may be considered like the use of aluminum or premium material such as Advance High Strength Steel (AHSS) or Pre Hardened Steel (PHS), which has a high cost considering the common sheet metal used in the vehicle structures.
2015-09-22
Technical Paper
2015-36-0316
Marcelo Luiz Vieira Lóss, Luciana Pisati Jansen
Abstract Costumers today are discerning, savvy, style conscious and extremely well aware of latest design trends and quite naturally, are lot more demanding than any generation before then. The growth in the application of plastic replacing natural leather, fabrics, metallic and ceramic materials, in order to increase productivity and decrease production costs, has been demanding process development to improve quality and not only mirror the appearance of the original materials, with their texture and colors but also presenting new opportunities and alternatives. The Challenge in automotive interior Design for emerging markets are the choice of materials finish, execution and harmony to guarantee customer satisfaction considering that costumers are spending more time on interior vehicles than ever.
2015-09-22
Technical Paper
2015-36-0311
Larissa Galera, Alex de Souza Rodrigues, Mark C. Malburg
Abstract In recent years, the concern about pollutants emissions has increased along with as customer requirements for more efficient internal combustion engine (ICE). To satisfy these demands, new technologies have been introduced in ICE, such as smaller engine bearings, a reduction in the number of cylinders, variable displacements, peak cylinder pressure (PCP) increases, among other things. Sliding bearings are responsible for vital function under engine operation and also friction losses, impacting on fuel consumption as well as pollutants emissions. To maximize the bearing’s performance, it is important to guarantee a hydrodynamic regime, in order to reduce wear and avoid power loss due to metal-to-metal friction, and consequently, premature failure of engine components. Material roughness indicates, with oil film, the lubrication regime as boundary, mixed or hydrodynamic.
2015-09-22
Technical Paper
2015-36-0477
Carmine Maria Di Sanctis, Waldyr Luiz Ribeiro Gallo
Abstract New devices and control techniques have been adopted to take advantage of variable valve timing properties to improve engine performance or load control. This paper presents a study focused on engine load control strategies associated with early intake valve closing or late intake valve closing. It can be shown that these load control modes can improve the indicated thermal efficiency of the engine as compared with the conventional throttle control. These strategies are sometime called Miller cycle or Atkinson cycle, since the real compression ratio becomes smaller than the expansion ratio. A thermodynamic spark-ignition engine simulation model was employed. The advantage of a simulation model is to conduct parametric studies without the need of complex experimental apparatus. In this way, a deep understanding of the physical phenomena can be achieved and the sole effect of the desired parameter can be shown.
2015-09-22
Technical Paper
2015-36-0267
Roberto Berlini Rodrigues da Costa, Rafael Lara Franco, Carlos Alberto Gomes, Raniro de Oliveira Alvarenga Coelho, Ramón Molina Valle
Abstract The design and development of highly efficient internal combustion engines require a thorough investigation of the fluid dynamic processes. This paper presents the experimentally determination and computational fluid dynamics simulations of the intake valves discharge coefficients of a four valve spark-ignition single cylinder research engine. The mass flow rate and air pressure were measured directly in the intake port for six different values of valve lift (4.68; 6.16; 7.48; 8.62; 9.46; and 10.49mm). The theoretical mass flow rates were obtained based on considerations of subsonic flow. Simulations were carried using the Star CCM+ commercial code. Mesh independence studies, using the velocity fields as monitors, have been made for reliability of the simulations. As a result, a methodology was successfully implemented to obtain the discharge coefficients experimentally and the simulations were validated with a maximum deviation of 6.62%.
2015-09-22
Technical Paper
2015-36-0136
Jony Javorski Eckert, Fabio Mazzariol Santiciolli, Eduardo dos Santos Costa, Ludmila Corrêa de Alkmin e Silva, Heron José Dionísio, Fernanda Cristina Corrêa, Franco Giuseppe Dedini
Abstract The gear shifting strategies strongly influence the vehicle fuel consumption because they change the powertrain inertia and the engine operation point. The literature normally presents gear shifting strategies based on the engine power and torque to improve the vehicle acceleration performance. Strategies based on fuel economy are difficult to determine due to a large number of factors that influence the engine behavior such as the available transmission ratios, required acceleration and vehicle speed. In this paper it was evaluated the influence of the addition of more gear ratios in the vehicle gearbox, which initially contains five available gear ratios. For each proposed gearbox configuration, the gear shifting strategy was optimized through an algorithm developed to improve the engine fuel consumption in the Brazilian standard urban driving cycle NBR6601.
2015-09-22
Technical Paper
2015-36-0104
Fernanda Pinheiro Martins, Rogério H. Onoda, Henedino Gutierrez
Abstract This paper deals with the study of different design configurations for intake valves and valve seats on a current production cylinder head and their effect on airflow behavior and optimization, under steady flow condition. The analysis was performed trough a Design for Six-Sigma methodology (DFSS). The cases were simulated through computational fluid dynamics (CFD) software and a prototype considering the best configuration was built and tested at flow bench. Correlation between simulation and experimental data was performed in order to validate the results for current, as well as, for future studies. The goal is to determine how geometric design variations on intake valve profiles and valve seats affect airflow on the particular cylinder head.
2015-09-22
Technical Paper
2015-36-0234
Levi N. da Silva, Kerolin F. Tessari, Mário W. Privatti, Alfons R. Wagner, Thiago Aurichio
Abstract High friction often involves high wear and power loss. The speed-temperature-dependence of grease lubricated contact ball bearings showed a variety of effects. The test apparatus is an axially-loaded angular contact ball bearing instrumented to measure the frictional torque as well as the transient temperature of the raceway. Effects of friction torque were examined at different speeds, operating temperatures and greases. Torque measurements and transient temperatures were compared for each grease, depending on the operating conditions. After experimental results, the grease formulation under different operation temperatures and different speeds showed significant influence on starting and rotating torques. Moreover the torque showed significant increase during the angular acceleration phase and decreased rapidly after the speed stabilization in all investigated greases.
2015-09-22
Technical Paper
2015-36-0172
George C. Ballardie, Rafael C. Martinez
Abstract Involute splines are widely used in the industry and in the automotive area. Some automotive driveline applications require involute splined couplings with an interference fit (zero backlash). Current methods of production of splines result in relative big dimensional and form deviations, which are increased when parts are heat treated. Grinding process of the spline’s teeth has a high cost and is not suitable for high volume production. There are three methods to achieve an interference fit: 1) Sorting parts with internal spline by using a tapered gage and producing the parts with external spline accordingly;2) Make the external spline with tapered teeth along the spline length;3) Make the external spline with a small helix angle (in the order of minutes of degree) along the spline length. This paper will approach the helix angle method and the process to find the best helix angle value for the interference fit.
2015-09-15
Technical Paper
2015-01-2423
Samarth Jain, Soumya Roy, Dhruv Gupta, Vasu Kumar, Naveen Kumar
Abstract The art and science of thrust vectoring technology has seen a gradual shift towards fluidic thrust vectoring techniques owing to the potential they have to greatly influence the aircraft propulsion systems. The prime motive of developing a fluidic thrust vectoring system has been to reduce the weight of the mechanical thrust vectoring system and to further simplify the configuration. Aircrafts using vectored thrust rely to a lesser extent on aerodynamic control surfaces such as ailerons or elevator to perform various maneuvers and turns than conventional-engine aircrafts and thus have a greater advantage in combat situations. Fluidic thrust vectoring systems manipulate the primary exhaust flow with a secondary air stream which is typically bled from the engine compressor or fan. This causes the compressor operating curve to shift from the optimum condition, allowing the optimization of engine performance. These systems make both pitch and yaw vectoring possible.
2015-09-15
Technical Paper
2015-01-2468
Rebecca Margetts, Chris Bingham, Tim Smith
Abstract Nonlinear Dynamic Inversion (NDI) has been previously reported for application to unmanned aircraft systems, due to the inherent attributes of allowing global co-ordinates to be used directly as control inputs. Here, the paper describes a model implementation of an ACHEON propulsion/thrust vectoring system that can be applied to a range of aircraft, with specific emphasis to thrust vectoring of a UAV. Results from the studies show the overall performance is shown to provide improved stability and dynamic characteristics when augmented with additional classical (PI based) control schemes.
2015-09-15
Technical Paper
2015-01-2464
Anna Suñol Jiménez, Tao Yang, Dean Vucinic
Abstract Thrust vectoring is an interesting propulsion solution in aeronautic applications due to its fast response, improving aircraft's performance for take-off, landing and flight, and enabling Short/Vertical Take-Off and Landing (S/VTOL). In this context, an attempt to design a radically new concept of thrust vectoring nozzle is in current development. This novel nozzle, called ACHEON, bases the jet deviation control on the interaction of two primary jets of different velocities, where the one with higher velocity entrains the one with lower velocity. Two cylindrical walls are positioned after the two air jets mixing. If the inlet conditions are not symmetric, the Coanda effect on the walls forces the resulting air jet to divert from the symmetry axis. This paper shows the experimental pressure distribution along the Coanda wall for different inlet.
2015-09-15
Technical Paper
2015-01-2592
Joao Pedro Malere, Wlamir Olivares Loesch Vianna
Abstract This paper presents a method to determine the root cause of an aircraft component failure by means of the aircraft fault messages history. The k-Nearest Neighbors (k-NN) and the Tree-Augmented naive Bayes (TAN) methods were used in order to classify the failure causes as a function of the fault messages (predictors). The contribution of this work is to show how well the fault messages of aircraft systems can classify specific components failure modes. The training set contained the messages history from a fleet and the root causes of a butterfly valve reported by the maintenance stations. A cross-validation was performed in order to check the loss function value and to compare both methods performance. It is possible to see that the use of just fault messages for the valve failure classification provides results that close to 2/3 and could be used for faster troubleshooting procedures.
2015-09-15
Technical Paper
2015-01-2600
Gustavo Franco Barbosa, Elton Candia Cordeiro, Fábio Rodrigues Costa
Abstract This paper presents a full automated solution that uses robots for manufacturing business jets primary parts. The purpose of this technological innovation is to increase productivity, improve the quality of final product, reduce costs with maintenance and consumable materials, in addition to meeting the requirements of ergonomics, occupational health and safety. So, better results have been sought in terms of process efficiency and technological innovation aligned to competitive market requirements related to industrial automation. The aim is to improve the manufacturing processes of the furniture parts, striving for excellence in every step by further adding value and reducing wastes in order to reduce manufacturing costs and enable greater customer satisfaction.
2015-09-15
Technical Paper
2015-01-2512
Mark W. Sydenham, Tim Brown
Abstract Electroimpact has developed an automated solution for installing OSI-Bolts on the HStab for Boeing's 787-9 aircraft. This solution utilizes Electroimpact's existing accurate robotic system together with new hardware designed specifically for OSI-Bolts. In addition to automated drilling and fastener installation, this system performs numerous quality checks to insure the installed fastener meets engineering requirements. Before installing the fastener, the system measures actual stack thickness and the length of the fastener to ensure that the proper grip is installed. Torque and angle feedback are recorded during installation which can be used determine if the fastener was installed correctly. The system will also automatically shave the small protuberance on the fastener head left by the broken off fastener stem, which is inherent to the OSI-Bolt. Figure 1 Cell Overview
2015-09-15
Technical Paper
2015-01-2453
Danilo Andreoli, Mario Cassaro, Manuela Battipede, Goodarz Ahmadi, Piergiovanni Marzocca
Abstract Flow control over aerodynamic shapes in order to achieve performance enhancements has been a lively research area for last two decades. Synthetic Jet Actuators (SJAs) are devices able to interact actively with the flow around their hosting structure by providing ejection and suction of fluid from the enclosed cavity containing a piezo-electric oscillating membrane through dedicated orifices. The research presented in this paper concerns the implementation of zero-net-mass-flux SJAs airflow control system on a NACA0015, low aspect ratio wing section prototype. Two arrays with each 10 custom-made SJAs, installed at 10% and 65% of the chord length, make up the actuation system. The sensing system consists of eleven acoustic pressure transducers distributed in the wing upper surface and on the flap, an accelerometer placed in proximity of the wing c.g. and a six-axis force balance for integral load measurement.
2015-09-15
Technical Paper
2015-01-2497
George Nicholas Bullen
Abstract The introduction of composite materials onto air vehicles has complicated the traditional hole/countersink assessment criteria due its finished-part thickness variability; softer and dissimilar properties than the metallic substructure where it is mounted and attached; and the increased attention to other acceptance criteria such as fiber tear, fiber pull, and moisture propagation in the hole that degrades fastener capability. The addition of composite materials further complicates the assembly process by adding a boundary layer of liquid shim or sealant between the composite piece (usually a skin) and the substructure. Current hole inspection systems are absent the ability to assess the interior condition of the composite hole such as fiber tear, damage to the liquid shim, and debris or burrs between the multiple stacks of dissimilar material.
2015-09-15
Journal Article
2015-01-2491
Paul Haworth, Donald Peterson, Curtis Hayes
Abstract A new high speed forming process for fatigue rated index head rivets used in wing panel assembly using ball-screw based servo squeeze actuation has been developed. The new process is achieved using a combination of force and position control and is capable of forming to 40,000 lbs at rates of up to 200,000 lbs/second whilst holding the part location to within +/− 10 thousandths of an inch. Multi-axis riveting machines often have positioning axes that are also used for fastener upset. It is often the case that while a CNC is used for positioning control, another secondary controller is used to perform the fastener upset. In the new process, it has been possible to combine the control of the upset process with the machine CNC, thus eliminating any separate controllers. The fastener upset force profile is controlled throughout the forming of the rivet by using a closed loop force control system that has a load cell mounted directly behind the stringer side forming tool.
2015-09-15
Journal Article
2015-01-2416
Charles E. Oberly, Michelle Bash, Benjamin R. Razidlo, Travis E. Michalak, Fernando Rodriguez
Abstract An IPTMS hardware facility has been established in the laboratories of the Aerospace Systems Directorate of the Air Force Research Laboratory (AFRL) at Wright-Paterson Air Force Base (WPAFB). This hardware capability was established to analyze the transient behavior of a high power Electrical Power System (EPS) coupled virtually to a Thermal Management System (TMS) under fast dynamic loading conditions. The system incorporates the use of dynamic electrical load, engine emulation, energy storage, and emulated thermal loads operated to investigate dynamics under step load conditions. Hardware architecture and control options for the IPTMS are discussed. This paper summarizes the IPTMS laboratory demonstration system, its capabilities, and preliminary test results.
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