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Viewing 271 to 300 of 6706
2015-04-14
Technical Paper
2015-01-0948
Le (Emma) Zhao, Ahmed Abdul Moiz, Jeffrey Naber, Seong-Young Lee, Sam Barros, William Atkinson
Abstract High-speed spray-to-spray liquid impingement could be an effective phenomenon for the spray propagation and droplet vaporization. To achieve higher vaporization efficiency, impingement from two-hole nozzles is analyzed in this paper. This paper focuses on investigating vaporization mechanism as a function of the impingement location and the collision breakup process provided by two-hole impinging jet nozzles. CFD (Computational Fluid Dynamics) is adopted to do simulation. Lagrangian model is used to predict jet-to-jet impingement and droplet breakup conditions while KH-RT breakup and O'Rourke collision models are implemented for the simulation. The paper includes three parts: First, a single spray injected into an initially quiescent constant volume chamber using the Lagrangian approach is simulated to identify the breakup region, which will be considered as a reference to study two-hole impinging jet nozzles.
2015-04-14
Journal Article
2015-01-1377
Hiroshi Yokoyama, Atsushi Otani, Naoyuki Shirota, Takao Umezawa
Abstract As an integral element of automotive wiper systems, an automotive washer system is designed to contribute to the security and safety of automobile-based societies by providing drivers with a clear field of vision. Washer fluid is discharged from washer nozzles, typically mounted on the engine hood, to distances of more than 300 mm across the windshield. However, the fluid discharged may fail to reach targeted areas due to the effects of wind pressure when the vehicle is moving at high speed or due to the increased viscosity of methanol in the washer fluid (at concentrations of 30-60 %) at low temperatures, resulting in failure to ensure a clear field of vision. We developed a self-oscillating washer nozzle to remedy these shortcomings of conventional washer systems. Based on CFD and optimization, the flow passage is designed to generate a stable discharge of washer fluid, even under conditions of high-speed air flow or low temperature.
2015-04-14
Journal Article
2015-01-0529
Jody N. Hall, Jason Coryell, Bill Wendt, Donald Adamski
Abstract With the implementation of Advanced High Strength Steel (AHSS) becoming more common for automotive manufacturers to reduce mass and/or improve performance, special stamping considerations must be made. Certain production parts may split at trimmed edges where strain levels are well below the forming limit curve of the respective grade, which is more applicable to necking fractures/splits. Similar to the presence of hard inclusion stringers (i.e. MnS) that can cause edge fractures in high strength low alloy steels, AHSS steels most susceptible to this phenomenon typically consist of dual phase or multiphase microstructures containing both a hard phase (martensite) and a soft phase (ferrite). Specific examples of these parts will be discussed, including studies to determine the root cause of the edge fracture and to communicate the solutions for consideration in appropriate standards and specifications.
2015-04-14
Journal Article
2015-01-0601
Madhavan Manivannan, Vesselin Stoilov, Derek O. Northwood
Abstract Ferritic nitrocarburizing offers excellent wear, scuffing, corrosion and fatigue resistance by producing a thin compound layer and diffusion zone containing ε (Fe2-3(C, N)), γ′ (Fe4N), cementite (Fe3C) and various alloy carbides and nitrides on the material surface. It is a widely accepted surface treatment process that results in smaller distortion than carburizing and carbonitriding processes. However this smaller distortion has to be further reduced to prevent the performance issues, out of tolerance distortion and post grinding work hours/cost in an automotive component. A numerical model has been developed to calculate the nitrogen and carbon composition profiles of SAE 1010 torque converter pistons during nitrocarburizing treatment. The nitrogen composition profiles are modeled against the part thickness to predict distortion.
2015-04-14
Technical Paper
2015-01-0527
Pierre-Olivier Santacreu, Guillaume Badinier, Jean-Benoit Moreau, Jean-Marc Herbelin
Abstract A new Ni-free martensitic stainless steel (MSS) was developed for hot stamped automotive parts, especially in order to design lightweight chassis part. After hot stamping simulation, the material exhibited a 1.2 GPa ultimate tensile strength with a minimum of 10% total elongation, in the as-quenched condition (Q) without any tempering treatment (Q+T). Moreover the material's chemical composition was optimized to improve the ductility at low temperature and during high strain rate mechanical testing. As a result, no brittle fracture in impact testing at −40°C was observed, and a good behavior in crash was recorded. To further assess the material's performances, high cycle fatigue properties of the grade have been characterized including the effects of machining and surface treatments. Results show that the fatigue limits at 2 million cycles for a stress ratio of −1, for both bare and shot peened surface are quite high and in the range of 580 MPa to 640 MPa.
2015-04-14
Technical Paper
2015-01-0520
Takaaki Kitahara, Takuo Imai, Osamu Ishigo, Miodrag Perovic
Abstract There has been a requirement for automotive bearings materials to be free of the toxic material lead, in accordance with ELV regulations and from the perspective of environmental problems. Currently, bismuth is used as a replacement for lead in copper alloy based main journal bearings and connecting rod bearings for automotive engines. In recent years, there has been changing to lead-free materials for truck engine bearings. Compared with automotive engines, lots of contaminations in the oil and local contact between the shaft and bearings can occur in truck engines. The ability to tolerate contamination and local contact is therefore required for truck engine bearings. In this development, we find that the addition of 8 mass% bismuth and 1.5 mass% molybdenum carbide particles into copper-tin alloy is effective for improving the ability which allow the contamination and local contacts.
2015-04-14
Technical Paper
2015-01-0949
Mathis Bode, Tobias Falkenstein, Vincent Le Chenadec, Seongwon Kang, Heinz Pitsch, Toshiyuki Arima, Hiroyoshi Taniguchi
Abstract Compared to conventional injection techniques, Gasoline Direct Injection (GDI) has a lot of advantages such as increased fuel efficiency, high power output and low emission levels, which can be more accurately controlled. Therefore, this technique is an important topic of today's injection system research. Although the operating conditions of GDI injectors are simpler from a numerical point of view because of smaller Reynolds and Weber numbers compared to Diesel injection systems, accurate simulations of the breakup in the vicinity of the nozzle are very challenging. Combined with the complications of experimental techniques that could be applied inside the nozzle and at the nozzle exit, this is the reason for the lack of understanding the primary breakup behavior of current GDI injectors.
2015-04-14
Journal Article
2015-01-0779
Gerald Gentz, Bryce Thelen, Paul Litke, John Hoke, Elisa Toulson
Abstract Turbulent jet ignition is a pre-chamber ignition enhancement method that produces a distributed ignition source through the use of a chemically active turbulent jet which can replace the spark plug in a conventional spark ignition engine. In this paper combustion visualization and characterization was performed for the combustion of a premixed propane/air mixture initiated by a pre-chamber turbulent jet ignition system with no auxiliary fuel injection, in a rapid compression machine. Three different single orifice nozzles with orifice diameters of 1.5 mm, 2 mm, and 3 mm were tested for the turbulent jet igniter pre-chamber over a range of air to fuel ratios. The performance of the turbulent jet ignition system based on nozzle orifice diameter was characterized by considering both the 0-10 % and the 10-90 % burn durations of the pressure rise due to combustion.
2015-04-14
Technical Paper
2015-01-1740
Kelsie S. Richmond, Stephen Henry, Russell Richmond, David Belton
Gasket materials are utilized for various different types of high temperature testing to prevent leaking at bolted joints. In particular, the automotive test services field uses flanged-gasket bolted exhaust joints to provide a convenient method for installation & removal of exhaust components like catalytic converters for aging, performance testing, etc. Recent improvements in the catalyst aging methods require flanged-gasket joints that can withstand exhaust temperatures as high as 1200°C. Gasket materials previously used in these applications like the graphite based gasket materials have exhibited physical breakdowns, severe leakage, and general thermal failures under these extreme temperatures. In order to prevent these leaks, metal-reinforced gasket materials in a number of configurations were introduced to these extreme temperature environments to evaluate their robustness to these temperatures.
2015-04-14
Technical Paper
2015-01-0921
Raul Payri, Jaime Gimeno, Pedro Marti-Aldaravi, Marcos Carreres
Abstract Proper initial conditions are essential to successfully perform a simulation, especially for highly transient problems such as Diesel spray injection. Until now, no much attention has been paid to the internal nozzle flow initialization because spray simulations are usually decoupled from the nozzle. However, new homogeneous models like Eulerian Spray Atomization (ESA) model allow to simulate the internal nozzle flow and the spray seamlessly. Therefore, the behavior of the spray for the first microseconds is highly influenced by the initial conditions inside the nozzle. Furthermore, last experiments confirm the presence of gas inside the nozzle between successive injections. This work deals with the initialization procedure in a way that mass flow rate and spray penetration curves are well predicted by the model.
2015-04-14
Technical Paper
2015-01-1499
Tadatsugu Takada, Kazuki Tomioka
Abstract Honda announced an independent right and left rear toe control system (first generation) in 2013 and presented it as the world's first. As stated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has achieved a balance between an enjoyable driving experience in which handling is performed at the driver's will (“INOMAMA” handling) and stable driving performance.(1) This first generation is optimally designed to the vehicle specifications such as suspension axial force and steering gear ratio of the vehicle to which the system is applied. For more widespread application of independent rear toe control technology, a next generation system (second generation) has been developed, which achieves both cost reduction and flexible system performance which can be adapted to a variety of vehicles. The system development began by setting the required target performance with consideration for adaptation to various car models.
2015-04-14
Technical Paper
2015-01-1715
Farouq Meddahi, Alain Charlet, Yann Chamaillard, Christian Fleck
Abstract Compressor models play a major role as they define the boost pressure in the intake manifold. These models have to be suitable for real-time applications such as control and diagnosis and for that, they need to be both accurate and computationally inexpensive. However, the models available in the literature usually fulfill only one of these two competing requirements. On the one hand, physics-based models are often too complex to be evaluated on line. On the other hand, data-based models generally suffer insufficient extrapolation features. To combine the merits of these two types of models, this work presents an extended approach to compressor modeling with respect to thermo- and aerodynamic losses. In particular, the model developed by Martin et al. [1] is augmented to explicitly incorporate friction, incidence and heat transfer losses. The resulting model surpasses the extrapolation properties of data-based models and facilitates the generation of extended lookup tables.
2015-04-14
Journal Article
2015-01-1720
Vincenzo De Bellis, Fabio Bozza, Silvia Marelli, Massimo Capobianco
Downsizing is widely considered one of the main path to reduce the fuel consumption of spark ignition internal combustion engines. As known, despite the reduced size, the required torque and power targets can be attained thanks to an adequate boost level provided by a turbocharger. However, some drawbacks usually arise when the engine operates at full load and low speeds. In fact, in the above conditions, the boost pressure and the engine performance is limited since the compressor experiences close-to-surge operation. This occurrence is even greater in case of extremely downsized engines with a reduced number of cylinders and a small intake circuit volume, where the compressor works under strongly unsteady flow conditions and its instantaneous operating point most likely overcomes the steady surge margin. In the paper, both experimental and numerical approaches are followed to describe the unsteady behavior of a small in-series turbocharger compressor.
2015-04-14
Technical Paper
2015-01-1287
Silvia Marelli, Giulio Marmorato, Massimo Capobianco, Andrea Rinaldi
In the last few years, the effect of diabatic test conditions on compressor performance maps has been widely investigated leading some authors to propose different correction models. The accuracy of performance maps constitutes the basis of the turbocharger matching with the engine, for which 1D procedures are more and more adopted. The classical quasi-steady approach generally used is based on the employment of compressor and turbine characteristic maps assuming adiabatic turbocharger conditions. The aim of the paper is to investigate the effect of heat transfer phenomena on the experimental definition of turbocharger maps, focusing on compressor performance. This work was developed within a collaboration between the Polytechnic School of the University of Genoa and CRITT M2A. The compressor steady flow behavior was analyzed through tests performed on different test rigs operating at the University of Genoa and at CRITT M2A, under various heat transfer conditions.
2015-04-14
Technical Paper
2015-01-1289
Fabian Herbst, Peter Eilts
Abstract A key technology for further improving the efficiency of gasoline engines lies in downsizing in combination with turbocharging. Decreasing the engine displacement greatly increases the demands on the turbocharging system. The charging of the engine with a single-stage turbocharger leads to a compromise to fulfill the requirements of the nominal power of the engine and the low-end torque. To avoid the use of complex two-stage boosting systems, it is necessary to increase the pressure ratio and the air flow rate at the same time. The wide speed and airflow range of gasoline engines intensify this trade-off. The use of a variable geometry turbine (VGT), additionally equipped with a wastegate bypass, offers great potential to meet the requirements on the turbine side. The range of stable operation of the compressor is limited by choke at high mass flow rates and surge at low mass flow rates.
2015-04-14
Technical Paper
2015-01-1280
Ahsanul Karim, Keith Miazgowicz, Brian Lizotte
The stable operation of turbocharger compressor at low flow rates is important to provide low end engine torque for turbocharged automotive engines. Therefore, it is important to be able to predict the lowest flow rates at different turbocharger speeds at which the surge phenomenon occurs. For this purpose, three-dimensional Computational Fluid Dynamics (CFD) simulations were performed on the turbocharger compressor including the entire compressor wheel and volute. The wheel consisted of six main and six splitter blades. Historically, flow bench and engine testing has been used to detect surge phenomenon. However a complete 3D CFD analysis can be performed upfront in the design to calculate low end compressor surge performance. The analyses will help understand the fundamental mechanisms of stalled flow, the surge phenomenon, and impact of compressor inlet conditions on surge.
2015-04-14
Technical Paper
2015-01-0139
Harish Kumar Gangwar, Ankur Sharma, Dipak Dabhole, Ambekar Prasad
Abstract Today urban buses are equipped with more air consuming devices for an example pneumatic doors, exhaust brake, air suspension and in SCR system to name a few. This has resulted in higher air demand leading to high compressor duty cycles which cause conditions (such as higher compressor head temperatures) that may adversely affect air brake charging system performance. These conditions may require additional maintenance due to a higher amount of oil vapor droplets being passed along into the air brake system. Factors that add to the duty cycle are air suspension, additional air accessories, use of an undersized compressor, frequent stops, excessive air leakage from fittings, connections, lines, chambers or valves, etc. This paper discussed about methodology used to reduce air consumption of air consuming devices used in urban bus application. Performance assessment of air consuming devices with minimum available air pressure was conducted and found satisfactory.
2015-04-14
Technical Paper
2015-01-0212
Mohamed El Morsy, Gabriela Achtenova
Abstract An efficient condition monitoring system provides early warning of faults by predicting them at an early stage. When a localized fault occurs in gears, the vibration signals always exhibit non-stationary behavior. The periodic impulsive feature of the vibration signal appears in the time domain and the corresponding gear mesh frequency (GMF) emerges in the frequency domain. However, one limitation of frequency-domain analysis is its inability to handle non-stationary waveform signals, which are very common when machinery faults occur. Particularly at the early stage of gear failure, the GMF contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations. An effective signal processing method would be necessary to remove such corrupting noise and interference. In this paper, a new hybrid method based on optimal Morlet wavelet filter and autocorrelation enhancement is presented.
2015-04-14
Technical Paper
2015-01-0228
Francesco Braghin, Francesco Salis
Abstract The objective of this study is to demonstrate the design and construction of an innovative active gear-shift and clutch for racecars, applied to a Formula Student car, based on the use of DC gear-motors. Racecars require extremely quick gear-shifts and every system to be as light as possible. The proposed solution is designed to reduce energy consumption, weight and improve gear-shift precision compared to traditionally employed electro-hydraulic solutions, although maintaining state of the art performances.
2015-04-14
Technical Paper
2015-01-0494
Sulki Seong, Wangoo Kim, Daesung Bae, Seungpyo Lee, Younggeol Cho, Kyeongdeok Yang
Abstract A rotating bearing must have an excellent durability life. Various studies have been conducted for a long time to predict the bearing durability life. However, the bearing durability life has been predicted by an analytic formula in terms of the raceway and ball. A finite element structural analysis has been carried out for a flange, commonly with an assumption of a static load. So it is difficult to consider the dynamic effects (Centrifugal force, Gyroscope effect) of the bearing, which is very important due to its high speed operation. In order to predict the accurate bearing durability life, the dynamic effects must be considered. This paper proposes a method for bearing durability life prediction, considering dynamic effects. Contact between the raceway and ball is one of the important factors to take into account for the dynamic effects of the bearing.
2015-04-14
Technical Paper
2015-01-0669
Nagarjun Jawahar, Saharash Khare
Abstract Automotive OEM's are looking for innovative solutions to capture the possible failure due to warpage and shrinkage of an insert molded part through virtual simulations with help of FEA tools, thereby saving the mold cost, material cost and time. This work demonstrates an approach to study and simulate the failure of an insert molded part which happened after few days of the part molding under idle condition. To simulate the above failure, an innovative approach coupling Moldflow and Abaqus software was derived. First, a flow simulation including phase change of plastic material was carried out with derived parameters, results of which were exported as input to the Abaqus structural solver. Secondly, a thermo-mechanical analysis of the model was then carried out considering the thermal and moisture effect on material property. A good correlation was achieved between the actual failure location and max stress location as predicted by said coupled approach.
2015-04-14
Technical Paper
2015-01-0323
Jörn Getzlaff, Tobias Dost, Thomas Lambert, Erik Lenk
Abstract The global development of oil prices and ongoing discussions with regard to meet future CO2-emission commitments necessitate new technologies and concepts in individual motor car traffic. While hybridization and electrification become more and more important on a small scale, the improvement in efficiency of conventional drive, especially in respect of SI engines, currently offers the highest potential in reducing fuel consumption and exhaust emissions. Thereby valve trains play a key role in the optimization of SI engines e. g. in connection with technologies and processes such as in-cylinder air-fuel mixing, combustion, HCCI, gas exchange, lean operation etc. Modern valve train systems entering mass production are despite of the fact of being called fully variable, yet cam-actuated systems. Thus variability and application are limited compared to direct (non-cam-actuated) engine control systems.
2015-04-14
Technical Paper
2015-01-0596
Oliver Scholz, Nikolas Doerfler, Lars Seifert, Uwe Zöller
Abstract Polymer seals are used throughout the automobile for a variety of purposes, and the consequences of a failure of such a seal can range from annoying in case of an A/C component to catastrophic in the case of brake components. With the constantly increasing demands for these components regarding e.g. pressure, tighter tolerances or new refrigerants come more stringent requirements for ensuring surface properties according to the specification for the specific application. While automatic inspection systems are available for a variety of defects, the area of seal inspection is still dominated by manual labor, partly because handling of these small, inexpensive parts is difficult and partly because visual coverage of the entire sealing surface poses a problem. It is also difficult for a human inspector to objectively assess whether or not a surface defect is critical, especially given that inspection of each seal must be completed within a few seconds.
2015-04-14
Journal Article
2015-01-0605
Guoyu Yang, Scott Kish
Strength and fatigue life prediction is very difficult for stamped structural steel parts because the manufacturing process alters the localized material properties. Traditional tensile tests cannot be used to obtain material properties due to size limitations. Because of this, FEA predictions are most often “directional” at best. In this paper an improved prediction methodology is suggested. With a material library developed from standard homogenous test specimens, or even textbook material property tables, localized strength and plastic strain numbers can be inferred from localized hardness tests(1). The new method, using standard ABAQUS static analysis (not commercial fatigue analysis software with many unknowns), is shown to be very accurate. This paper compares the new process FEA strength and fatigue life predictions to laboratory test results using statistical confidence intervals.
2015-04-14
Journal Article
2015-01-0662
Weiguo Zhang, Mac Lynch, Robert Reynolds
Abstract A turbocharger is currently widely used to boost performance of an internal combustion engine. Generally, a turbocharger consists of a compressor which typically is driven by an exhaust turbine. The compressor will influence how the low frequency engine pulsation propagates in the intake system. The compressor will also produce broad-band flow induced sound due to the turbulence flow and high frequency narrowband tonal sound which is associated with rotating blade pressures. In this paper, a practical simulation procedure based on a computational fluid dynamics (CFD) approach is developed to predict the flow induced sound of a turbocharger compressor. In the CFD model of turbocharger compressor, the unsteady, moving wheel, detached eddy simulation (DES) approach are utilized. In this manner, both the broad-band and narrow-band flow induced sound are directly resolved in the CFD computation.
2015-04-14
Technical Paper
2015-01-0666
Chenguang Li, Fue-Sang Lien, Eugene Yee, Mike Dong
Abstract A deeper understanding of the complex phenomenology associated with the multiphase flow-induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve. More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized to facilitate the modeling of this complicated two-phase fluid-structure interaction problem. For a two-phase flow through the valve, our simulations showed that the deformation and breakup of gas bubbles in the gap between the poppet and the valve seat generates a vibration that arises primarily from the force imbalance between the spring and the two-phase fluid flow induced forces on the poppet.
2015-04-14
Technical Paper
2015-01-0458
Subrata Sarkar, Sudarshan Kumar, Atul Singhal, Surbhi Kohli, Kailash Golecha, Jubin George
Abstract The objective of this paper is to provide a robust design solution for a Jet pump which is used for fuel removal from an Active Drain Liquid Trap (ADLT). This jet pump can work for both Gasoline and Diesel based automobiles. The major focus area of this paper, is improvement in the robustness of Jet pump performance parameters, such as motive flow and induced flow. A design study for such a two fuel application was first initiated using Taguchi's robust design approach. In order to reduce the inventory complexity and cost, a common design possibility was then addressed. Two approaches for robust design have been discussed, namely the Taguchi Methodology (Orthogonal Cross Array based design) and the Dual RSM (Response Surface Methodology) Technique. Results show that the Dual RSM provides improved performance with reduced variation, as compared to Taguchi's approach.
2015-04-14
Technical Paper
2015-01-0864
Bronson Patychuk, Ning Wu, Gordon McTaggart-Cowan, Philip Hill, Sandeep Munshi
Abstract Natural gas high pressure direct injection (HPDI) engines represent a technology with the potential for lower engine-out emissions and reduced fuel costs over a diesel engine. This combustion process uses a direct injection of natural gas, into the combustion chamber of a high compression ratio engine, to maintain diesel engine performance. As natural gas will not auto-ignite at typical engine conditions, a small quantity of diesel pilot fuel is used to initiate the combustion event. One potential technique to improve engine performance is the optimization of the intake and exhaust valve timings. To experimentally investigate these effects, tests were performed on a single cylinder engine based on Westport Innovation's 15L HD engine. The intake valve closing time was varied both before and after the standard closing (EIVC and LIVC). Early closing of the exhaust valve was also tested (EEVC).
2015-04-14
Technical Paper
2015-01-0923
Mohamed Chouak, Alexandre Mousseau, Damien Reveillon, Louis Dufresne, Patrice Seers
Abstract The transient characteristics of the internal flow dominate all the ensuing processes: spray, fuel-air mixture formation as well as combustion and pollutants formation. Therefore, it is crucial to understand the dynamics of the injectors' internal flow. The objective of this work is to study all transient effects that may impact the internal flow of a single hole injector under different conditions. Since the numerical investigation of such a complex flow is hampered by several factors for the real operating conditions-namely the turbulence, the cavitation and the needle motion-this work is divided into two parts. In the first part, only the effects of turbulence and cavitation are considered through the study of the effects of the fuel properties as well as the injection conditions at the fully open needle position. The impact of these effects is studied by means of the Reynolds and the cavitation number.
2015-04-14
Technical Paper
2015-01-0944
Maryam Moulai, Ronald Grover, Scott Parrish, David Schmidt
Abstract A computational and experimental study was performed to characterize the flow within a gasoline injector and the ensuing sprays. The computations included the effects of turbulence, cavitation, flash-boiling, compressibility, and the presence of non-condensible gases. The flow domain corresponded to the Engine Combustion Network's Spray G, an eight-hole counterbore injector operating in a variety of conditions. First, a rate tube method was used to measure the rate of injection, which was then used to define inlet boundary conditions for simulation. Correspondingly, injection under submerged conditions was simulated for direct comparison with experimental measurements of discharge coefficient. Next, the internal flow and external spray into pressurized nitrogen were simulated under the base spray G conditions. Finally, injection under flashing conditions was simulated, where the ambient pressure was below the vapor pressure of the fuel.
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