Criteria

Text:
Display:

Results

Viewing 241 to 270 of 6755
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
2015-36-0136
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
2015-36-0112
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
2015-36-0477
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
2015-36-0557
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
2015-36-0267
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
2015-36-0286
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
2015-36-0311
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
2015-36-0316
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
2015-36-0451
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
2015-36-0141
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
2015-36-0234
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
2015-01-2453
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
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
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
2015-01-2416
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.
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
2015-01-2592
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
Journal Article
2015-01-2610
Patrick Land, Richard Crossley, David Branson, Svetan Ratchev
Abstract There is a growing demand for composites to be utilised in the production of large-scale components within the aerospace industry. In particular the demand to increase production rates indicates that traditional manual methods are no longer sufficient, and automated solutions must be sought. This typically leads to automated forming processes where there are a limited number of effective options. The need for forming typically arises from the inability of layup methods to produce complex geometries of structural components. This paper reviews the current state of the art in automated forming processes, their limitations and variables that affect performance in the production of large scale components. In particular the paper will focus on the application of force and heat within secondary forming processes. It will then review the effects of these variables against the structure of the required composite component and identify viability of the technology.
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
2015-01-2468
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
2015-01-2512
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
2015-09-06
Technical Paper
2015-24-2526
Borislav Klarin, Thomas Resch, Chiara Sessarego, Giorgio Spanu, Gianni Lamonaca
This paper presents a methodology for numerical investigation of a full flexible balancer drive together with engine and crank train under realistic operating conditions where shaft dynamics, gear contact and rattle impacts, gear root stresses and friction losses in bearings and gear interaction are taken into account and can be balanced against each other to achieve the design criteria. Gear rattle is driven by the speed fluctuation of the crank train, the resistance torque (mainly friction), shaft inertia and the backlash in the gears. The actual trend to engine downsizing and up-torqueing increases the severity to rattle as engines are running on higher combustion pressures. This increases torque and speed fluctuation, which makes the detailed investigation in this torque transfer even more demanding. A common method to reduce gear rattle is the usage of so-called scissors gears.
2015-09-06
Technical Paper
2015-24-2524
José Lujan, José V. Pastor, Héctor Climent, Manuel Rivas
Abstract On actual gasoline turbocharged engines it is common to use a compressor by-pass valve in order to solve the compressor surge problem when the throttle pedal position is released and closes rapidly. The paper deals with a methodology based on experiments to measure the discharge coefficient of an integrated compressor by-pass valve, to understand the possible difference between the steady flow test bench and turbocharger test bench discharge coefficient measurements. To determine if there is some compressor outlet flow field influence due to compressor blades rotation that could modify the discharge coefficient measurement, compared to the steady flow test bench measurements, a fully instrumented turbocharger was used to measure the difference between steady flow test bench and turbocharger test bench discharge coefficients results.
2015-09-06
Technical Paper
2015-24-2467
Alessandro Ferrari, Federica Paolicelli
Abstract A challenging task that is required to modern injection systems is represented by the enhanced control of the injected quantities, especially when small injections are considered, such as, pilot and main shots in the context of multiple injections. The propagation of the pressure waves triggered by the nozzle opening and closure events through the high-pressure hydraulic circuit can influence and alter the performance of the injection apparatus. For this reason, an investigation of the injection system fluid dynamics in the frequency domain has been proposed. A complete lumped parameter model of the high-pressure hydraulic circuit has been applied to perform a modal analysis. The visualization of the main vibration modes of the apparatus allows a detailed and deep comprehension of the system dynamics. Furthermore, the possible resonances, which are induced by the action of the external forcing terms, have been identified.
2015-09-06
Technical Paper
2015-24-2470
Daniel Pearce, Yannis Hardalupas, A.M.K.P Taylor
The measurement of the rate of fuel injection using a constant volume, fluid filled chamber and measuring the pressure change as a function of time due to the injected fluid (the so called “Zeuch” method) is an industry standard due to its simple theoretical underpinnings. Such a measurement device is useful to determine key timing and quantity parameters for injection system improvements to meet the evolving requirements of emissions, power and economy. This study aims to further the understanding of the nature of cavitation which could occur in the near nozzle region under these specific conditions of liquid into liquid injection using high pressure diesel injectors for heavy duty engines. The motivation for this work is to better understand the temporal signature of the pressure signals that arise in a typical injection cycle.
2015-09-06
Journal Article
2015-24-2472
Nikolaos Papadopoulos, Pavlos Aleiferis
The design of a Diesel injector is a key factor in achieving higher engine efficiency. The injector's fuel atomisation characteristics are also critical for minimising toxic emissions such as unburnt Hydrocarbons (HC). However, when developing injection systems, the small dimensions of the nozzle render optical experimental investigations very challenging under realistic engine conditions. Therefore, Computational Fluid Dynamics (CFD) can be used instead. For the present work, transient, Volume Of Fluid (VOF), multiphase simulations of the flow inside and immediately downstream of a real-size multi-hole nozzle were performed, during and after the injection event with a small air chamber coupled to the injector downstream of the nozzle exit. A Reynolds Averaged Navier-Stokes (RANS) approach was used to account for turbulence. Grid dependency studies were performed with 200k-1.5M cells.
2015-09-06
Journal Article
2015-24-2462
Fabio Auriemma, Heiki Tiikoja
The acoustic impedance exhibited by a new type of element for noise control, the Micro-Grooved Elements (MGEs), has been widely investigated in this paper. The MGEs are typically composed of two overlying layers presenting macroscopic slots and a number of micro-grooves on one of the contact surfaces. The micro-grooves result in micro-channels as the layers are assembled to form the element. Similarly to Micro-Perforated Elements (MPEs), the MGEs have been proved to provide effective dissipation of acoustic energy by the means of viscous losses taking place in the micro-channels. However, in contrast to the MPEs, the MGEs use the grooves, instead of the holes, in which the air is forced to pass through. It results in more cost effective elements, which have been found to represent an adequate alternative for fibrous materials, typically present in silencer units.
Viewing 241 to 270 of 6755

Filter

Subtopics