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Viewing 1 to 30 of 1489
2005-04-11
Technical Paper
2005-01-1937
Gerald A. Szekely, Alex C. Alkidas
This work describes an experimental investigation on the stratified combustion and engine-out emissions characteristics of a single-cylinder, spark-ignition, direct-injection, spray-guided engine employing an outward-opening injector, an optimized high-squish, bowled piston, and a variable swirl valve control. Experiments were performed using two different outward-opening injectors with 80° and 90° spray angles, each having a variable injector pintle-lift control allowing different rates of injection. The fuel consumption of the engine was found to improve with decreasing air-swirl motion, increasing spark-plug length, increasing spark energy, and decreasing effective rate of injection, but to be relatively insensitive to fuel-rail pressure in the range of 10-20 MPa. At optimal injection and ignition timings, no misfires were observed in 30,000 consecutive cycles.
2005-04-11
Technical Paper
2005-01-1936
Yiqing Yuan, Zulfikar Ali, Pradeep Attibele
An impinging-flow based methodology of enhancing the heat transfer in the grooves of a lockup clutch is proposed and studied. In order to evaluate its efficacy and reveal the mechanism, the three-dimensional flow within the groove was solved as a conjugate heat transfer problem in a rotating reference frame using the commercial CFD code FLUENT. The turbulence characteristics were predicted using k-ε model. The comparison of cooling effect was made between a simple baseline groove pattern and a typical flow-impingement based groove pattern of the same groove-to-total area ratio in terms of heat rejection ratio, maximum surface temperature, and heat transfer coefficient. It is found that more heat can be rejected with the impinging-flow based groove from the friction surface than with the baseline while the maximum surface temperature is lower in the former case.
2005-04-11
Technical Paper
2005-01-1939
Nicholas Stephen Reinholtz
Research in the field of transportation has the ability to accelerate our society and benefit the common good. Because of this, it is important that the federal government continues to fund research in this field. The United States traditionally funds research through three basic methods: grants, procurement contracts and cooperative agreements. With the recent media attention and apparent success of the privately funded Ansari X Prize, the federal government should consider sponsoring similar inducement prizes to promote research and entrepreneurship in the transportation sector. The federal government should also make sure privately funded inducement prizes are safely administered and relatively free of bureaucracy. Inducement prizes can stimulate interest and promote competition towards a goal, and doing so can showcase America's engineering excellence and pioneering spirit.
2005-04-11
Technical Paper
2005-01-1938
Mingde Su, Guy Nusholtz, Venkatesh Agaram
This paper presents a 2D model for frontal vehicle-to-vehicle crashes that can be used for fleet modeling. It presents the derivational details and a preliminary assessment of the model. The model is based on rigid-body collision principles, enhanced adequately to represent energy dissipation and lateral engagement that plays a significant role in oblique frontal vehicle-to-vehicle crashes. The model employs the restitution and the apparent friction in order to represent dissipation and engagement respectively. It employs the impulse ellipse to identify the physical character of the crash, based on the principal directions of impulse. The enhancement of the rigid body collision model with restitution and apparent friction is based on collision simulations that use very simple finite element vehicle representations.
2005-04-11
Technical Paper
2005-01-1925
Myong-Young Lee, Yeong-Ho Ha, Joon-Ho Shin, Jung-Hyang Park, Cheol-Hee Lee
This study proposes a new algorithm that can render a realistic image of an automotive rear lamp using the backward ray tracing method. To produce a realistic image similar to that perceived by the human eye, the physical transformation procedures of light energy are traced by a spectral interaction definition. The incident light energy at the eye point estimated by a ray tracing algorithm is represented by XYZ tri-stimulus values, which are then converted into RGB values considering the particular display device. A more effective form of light source modeling than the Monte-Carlo integration method is also applied for accurate simulation. Finally, comparisons of traced results and real measurements are performed in terms of the spectral distribution, image detail, and visual experiments.
2005-04-11
Technical Paper
2005-01-1927
Sangho Lee, Hyun Sung, Unkoo Lee
This paper presents the development of the active geometry control suspension(AGCS) system as the world-first, unique and patented chassis technology, which has more advantages than the conventional active chassis control systems in terms of basic concept. The control approach of the conventional systems such as active suspensions(slow active, full active) and four wheel steering(4WS) system is directly to control the same direction with acting load to stabilize vehicle behavior resulting from external inputs, but AGCS controls the cause of vehicle behaviors occurring from vehicle and thus makes the system stable because it works as mechanical system after control action. The effect of AGCS is the remarkable enhancement of avoidance performance in abrupt lane change driving by controlling the rear bump toe geometry.
2005-04-11
Technical Paper
2005-01-1935
Liguang Li, Zongjie Hu, Shui Yu
Fuel films of several typical fuels were investigated by means of thermal gravity analysis (TGA). To make diesel homogeneous charge by means of film evaporation, it was concluded that to get 30%∼50% evaporation of film, the wall temperature should be set between 150°C and 180°C for diesel and 40°C∼60°C for gasoline, and to get 95% evaporation of film, the wall temperature should be set between 200°C and 250°C for diesel and 50°C∼100°C for gasoline, when the thickness of the fuel film is about 40 μ m. Based on the properties of fuels, the evaporation characteristics of diesel under 100°C should be improved.
2005-04-11
Technical Paper
2005-01-1929
Frances E. Lockwood, Z. George Zhang, T. Reg Forbus, Stephen U.S. Choi, Ying Yang, Eric A. Grulke
It has been shown that the addition of a small amount of nanoparticles into a fluid results in anomalous increase in the thermal conductivity of the mixture, and the resulting nanofluid may provide better overall thermal management and better lubrication in many applications, such as heat transfer fluids, engine oils, transmission fluids, gear oils, coolants and other similar fluids and lubricants. The potential benefits of this technology to the automotive and related industries would be more efficient engines, reduced size and weight of the cooling and propulsion systems, lowered operating temperature of the mechanical systems, and increased life of the engine and other mechanical systems. The new mechanisms for this phenomenon of anomalous thermal conductivity increase have been proposed. The heat transfer properties of a series of graphite nanofluids were presented, and the experimental results were compared with the conventional heat transfer theory for pure liquids.
2005-04-11
Technical Paper
2005-01-1945
P. Schoeggl, W. Kriegler, E. Bogner
The rapidly growing complexity and the growing cross linking of powertrain components leads to longer development times, especially in the vehicle calibration process. The number of systems which need to be fitted to each other and the number of parameters to be calibrated in the particular systems are increasing tremendously. The extensive use of simulation promises to reduce the calibration effort by providing pre-optimized parameter sets. This paper describes a new simulation methodology by the interlinking of advanced vehicle simulation and evaluation tools, in particular the AVL-tools CRUISE, VSM and DRIVE. This methodology allows to semi automatically pre-optimize powertrain and vehicle parameters before hardware is involved. So far the pre-calibration of vehicle and powertrain parameters by simulation was not satisfying because of the missing of a reliable evaluation tool for the produced simulation results.
2005-04-11
Technical Paper
2005-01-1944
Blair S. Patty, Leo Novak, Hoang Pham
Field cracking in some instrument panels (IP) manufactured with a competitive grade of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) material was observed in high temperature/high humidity geographies. OEMs and tier molders are: 1) questioning the thermal and hydrolytic stability of the various suppliers' PC/ABS resins, and 2) converting to grades with advantaged stability. A study was undertaken to compare the thermal and hydrolytic stability of two suppliers' high flow PC/ABS resins. Materials were aged at 90C/95% relative humidity up to 1000 hours. Samples were tested to compare the retention of properties. This paper will discuss the experimental procedures, resulting data, and the common factor in the PC/ABS resins showing the best stability.
2005-04-11
Technical Paper
2005-01-1947
Kouji Yamamoto, Koichi Nakahara, Hiroshi Makino, Shingo Sato, Tetsuo Hirakawa
A new LTCC (Low Temperature Co-fired Ceramics) substrate material has been developed for automotive applications used for harsh environment ECU (Electronic Control Unit). Features of the LTCC include high mechanical strength, high dimensional tolerance (+/- 0.1 %), low conductor resistance (2 mΩ / square), and Pb-free thick film resistor systems on the LTCC. These characteristics of the LTCC substrate are suitable for automotive harsh environment applications. Surface conductors are completely covered with Ni/Au plating, which provide sufficient wire bondability for both Au and Al wires. The resistor system consists of Pb-free RuO2 resistor and Pb-free over coated glass which provides protection. Low ohm resistor also consists of Pb-free Ag/Pd material. All of the resistors can be trimmed by laser with their resistances controlled within +/- 1 %. The resistors have less than 1% drift after 3,000 temperature cycles at -40 and 150 degree C condition.
2005-04-11
Technical Paper
2005-01-1941
Peter H. Dugdale, Roger J. Rademacher, Bruce R. Price, Jay W. Subhedar, Roger L. Duguay
General Motors adds a larger displacement more powerful variant to its global 4-cylinder engine family. The new Ecotec 2.4L VVT, being introduced in the 2006 Pontiac Solstice is the latest variant within the Ecotec engine family. This new engine is built on the heritage and excellent reputation of the Ecotec 2.2L(1), the global 4-cylinder engine introduced for the North American market in the 2000 model year Saturn L-series. Ecotec engines are now offered in many additional GM platforms in North America as well as in Europe. The Ecotec 2.4L VVT shares many parts with the Ecotec 2.2L(1), with addition of cam phaser technology to enable variable valve timing (VVT) along with several structural enhancements. The Ecotec 2.4L VVT produces 25% more power, impressive torque at lower engine speeds and offers a number of other advantages.
2005-04-11
Technical Paper
2005-01-1940
Caroline A. Cochran
The economic benefits and market expansions enabled by the regional expansion of automobile standards have reached a natural limit due to an international clash of different standards systems. The automobile industry and market are now truly global, however, standards remain a regional and national issue. Until these standards are harmonized, they will act as a barrier to trade. Industry, standards developing organizations (SDOs), and governments worldwide have recognized the value in harmonizing global standards by the creation of global technical regulations (GTRs), but each approach the issue with their own agenda. This paper evaluates the differing goals of industry, U.S. government and U.S.-domiciled SDOs, obtained by interview with experts from each, while providing a comprehensive overview of the implications of standards harmonization, and finally, recommendations for the advancement of GTRs.
2005-04-11
Technical Paper
2005-01-1943
Tom Froling, Tadge Juechter
This paper is intended to give a general overview of the key aerodynamic developments for the 2006 Chevrolet Corvette C6 Z06. Significant computational and wind tunnel time were used to develop the 2006 Z06 to provide it with improved high speed stability, increased cooling capability and equivalent drag compared to the 2004 Chevrolet Corvette C5 Z06.
2005-04-11
Technical Paper
2005-01-1942
Spencer C. Sorenson, Elbert Hendricks, Sigurjon Magnusson, Allan Bertelsen
With the current trend towards engine downsizing, the use of turbochargers to obtain extra engine power has become common. A great difficulty in the use of turbochargers is in the modelling of the compressor map. In general this is done by inserting the compressor map directly into the engine ECU (Engine Control Unit) as a table. This method uses a great deal of memory space and often requires on-line interpolation and thus a large amount of CPU time. In this paper a more compact, accurate and rapid method of dealing with the compressor modelling problem is presented. This method is physically based and is applicable to all turbochargers with radial compressors for either Spark Ignition (SI) or diesel engines.
2005-04-11
Technical Paper
2005-01-1913
Won-Joo Roh, Sok-Hyun Cho, Jae In Park
Noise from automotive fuel tanks is generated by sloshing flow of fuel. Flow inside fuel tanks is incompressible, turbulent and free surface problem which is analyzed by Marker and Cell (MAC) algorithm. The simulation result of gross sloshing flow pattern is compared and verified by experiments with transparent fuel tanks. Characteristics of impact pressure on the tank wall are analyzed to find noise source on the wall. It is influenced by both the inertia of fuel mass and the dynamic motion of sloshing flow. In addition, a parametric study has been done to decrease impact pressure by changing its dimensions and shape.
2005-04-11
Technical Paper
2005-01-1914
Darko Filipi, Ales Alajbegovic, Anthony B. Christie
Cavitation induced cylinder liner erosion can be a significant durability problem in high power density diesel engines. It is typically discovered in the field, thus causing costly redesigns. The application of a predictive simulation to analyze the liner cavitation process upfront could identify the problem early on and enable significant savings. Hence, this work investigates the ability of the computational fluid dynamics (CFD) multiphase flow simulation tool to handle vibration induced cavitation. A flow of liquid through a U-shaped duct is analyzed, where a middle segment of the duct is set to vibrate in a manner resembling vibration of the cooling jacket walls in an internal combustion engine. Velocity, pressure and vapor concentration fields are tracked for two cases, distinguished by different frequencies of duct wall vibration.
2005-04-11
Technical Paper
2005-01-1909
Scott A. Miers, Carl L. Anderson, Jason R. Blough, M. Koray Inal
The objective of this investigation was to identify the impingement event on a diesel piston surface. Eight fast-response, surface thermocouples were installed in one of the pistons of a 2.0 liter, four-cylinder, turbo-charged diesel engine (97 kW @ 3800 rpm). Piston temperatures were transmitted from the engine using wireless microwave telemetry. An impingement signal was identified on the piston bowl lip. A simple parameter for characterizing the impingement event is proposed. The results show an impingement signature at one of the bowl lip thermocouples, under specific operating conditions.
2005-04-11
Technical Paper
2005-01-1910
Yang Yang, William W. Liou
Three-dimensional numerical simulations using FLUENT [1] were performed to model the airflow over the Sunseeker, an award-winning solar car that was designed and built at Western Michigan University. Converged numerical solutions on three different grids are reported and compared with the available experimental data, which include the lift and the drag coefficients. Also reported are the results obtained by using the second-order upwinding discretization on one of the grids. The comparison shows that the computed lift coefficients agree well with the experimental data for all the three grids and the different orders of numerical methods, indicating that the pressure field is well captured. The agreement with the data for drag coefficient varies, which appears to suggest a higher degree of dependency on the grid distributions than that for the lift coefficient. These results are discussed in terms of their implications for the simulations of similar low-drag vehicles.
2005-04-11
Technical Paper
2005-01-1908
K. S. Choi, J. Pan, S. Ho
In this paper, the effects of roller geometry on contact pressure and residual stress in crankshaft fillet rolling are investigated by a two-dimensional finite element analysis. The fillet rolling process is first introduced to review some characteristics of the rolling tools. A two-dimensional plane strain finite element analysis is then employed to qualitatively investigate the influence of the roller geometry. Computations have been conducted for eight different contact geometries between the primary roller and the secondary roller to investigate the geometry effect on the contact pressure distribution on the edge of the primary roller. Fatigue parameters of the primary rollers are also estimated based on the Findley fatigue theory. Then, computations have been conducted for three different contact geometries between the primary roller and the crankshaft fillet to investigate the geometry effect on the residual stress distribution near the crankshaft fillet.
2005-04-11
Technical Paper
2005-01-1906
Paul V. Spiteri, Yung-Li Lee, Ray Segar
This report explores the relationship of different failure criteria - specifically, surface cracks, stiffness changes, and two-piece failures - on rolled, ductile, cast-iron crankshafts. Crankshaft samples were closely monitored throughout resonant bending fatigue testing and were taken to near complete fracture. By monitoring resonance shifts of the samples during testing, stiffness changes and cracks were monitored. These data showed that an accelerating frequency shift was sufficient to indicate imminent two-piece failure and that this condition can be used as a failure criterion. Fatigue studies on two different crankshafts using this failure criterion were compared to those using a surface crack failure criterion. This comparison showed that using the surface crack failure criterion erroneously decreased the apparent fatigue life of the crankshaft significantly.
2005-04-11
Technical Paper
2005-01-1905
Timothy C. Scott, Larry K. McDonald
Advanced design of modern engine cooling and vehicle HVAC components involves sophisticated simulation. In particular, front end air flow models must be able to cover the complete range of conditions from idle to high road speeds involving multiple fans of varying types both powered and unpowered. This paper presents a model for electric radiator cooling fans which covers the complete range of powered and unpowered (freewheel) operation. The model applies equally well to mechanical drive fans.
2005-04-11
Technical Paper
2005-01-1904
Kumar Srinivasan, George Woronowycz, Michael Zabat, John Tripp
Vehicle thermal protection is an important aspect of the overall vehicle development process. It involves optimizing the exhaust system routing and designing heat shields to protect various components that are in near proximity to the exhaust system. Reduced time to market necessitates an efficient process for thermal protection development. A robust procedure that utilizes state of the art CFD simulation techniques proactively during the design phase is described. Simulation allows for early detection of thermal issues and development of countermeasures several months before prototype vehicles are built. Physical testing is only used to verify the thermal protection package rather than to develop heat shields. The new procedure reduces the number of physical tests and results in a robust, efficient methodology.
2005-04-11
Technical Paper
2005-01-1923
G. Fabbri, F. Piraccini, R. Rossi, S. Di Piazza, A. Ferraresi
A numerical multi-scale method for the analysis of heat exchangers is presented. In the present work this methodology has been used to analyze the heat exchangers of the Ducati 999 motorbike cooling system. In order to compute the flowfield around the vehicle and to obtain the velocity distribution inside heat exchangers volume, a finite volume model has been adopted. A distributed model is then used to analyze the heat exchange process that takes place into the heat exchanger for different velocity distributions and for a constant liquid inlet temperature. The results of the finite volume analysis are described with particular emphasis on the airflow distribution across the thermal devices. Finally, a comparison of the results obtained by means of the distributed-parameters model for the uniform airflow case and those obtained with the computed airflow distributions is presented.
2005-04-11
Technical Paper
2005-01-1924
Hrishikesh V. Deo, Nam P. Suh
In this paper, we have presented a novel design for a customizable automotive suspension system with independent control of stiffness, damping and ride-height; and demonstrated the concept through a suspension prototype. The major motivation for this design is to avoid the trade-offs, involved in suspension design, which arise from the conflicting requirements of comfort and handling. The objective of this paper is to explore the possible applications of variable stiffness and variable ride-height suspension system to achieve improved vehicle dynamics. The capability of achieving the desired performance depending on user preference, vehicle speed, road conditions and maneuvering inputs using the proposed system is demonstrated. The application of variable stiffness to achieve real-time alteration of pitch and bounce motion centers, and real time alteration of anti-pitch and anti-dive characteristics is discussed.
2005-04-11
Technical Paper
2005-01-1921
Peter Fischer
A thermal analysis of an automotive fog lamp is performed using the commercial computational fluid dynamics package CFX-4. The three-dimensional, steady-state analysis accounts for convection and radiation within the fluid domain and conduction and radiation within the solid domain. Radiation is modelled using a multi-band ray-tracing approach. The geometry is meshed in detail including bulb and filament. Results show a temperature distribution characterised by a hot spot on the lens. It is mainly caused by radiation which is specular reflected at the reflector and partly absorbed by the lens. The housing temperature field shows warmer areas on top and colder areas at the bottom induced by convective heat redistribution due to the air flow inside the fog lamp housing. The calculation is experimentally verified. The good agreement between measured and calculated temperatures approves the simulation method.
2005-04-11
Technical Paper
2005-01-1922
David Tweddell, Clayton Sloss, Thomas Werner
A strategy for performing transient computational fluid dynamics simulations of systems consisting of exhaust manifolds and close-coupled catalytic converters is described. The motivation for performing such a simulation is discussed, with reference to the literature, and a description of the modelling approach is given. The differences between steady-state and transient figures of merit for catalyst utilization and sensor positioning are discussed, including the development of a novel figure of merit for sensor positioning which is suitable for implementation in a transient simulation. A comparison between steady-state and transient simulation results for a typical simulation case is shown. Other simulation features for future development are discussed briefly.
2005-04-11
Technical Paper
2005-01-1917
Santosh Kini, Nick Mapara, Richard Thoms, Peter Chang, Michal Nemec
Understanding how pump leakage can be predicted and minimized is an important aspect of pump design for subsequent improvements in pump performance. The Gerotor pump can have leakage rates that significantly affect performance and overall efficiency. Simulations were conducted on a Gerotor pump incorporating 1) a CFD code, CFD-ACE+ with a proven cavitation model and 2) a coupled structural solver to determine deflection of the cover plate in the pump assembly due to variation in internal pressure profiles during operation. The computed results (pressure, cavitation and deflection) show trends similar to that seen in experiments and a quantitative comparison is presented.
2005-04-11
Technical Paper
2005-01-1918
L. Allocca, M. Auriemma, F. E. Corcione, G. Valentino, S. Fontanesi, V. Gagliardi, S. Malaguti, G. Riganti
The paper aims at providing information about the spray structure and its evolution within the combustion chamber of a heavy duty direct injection (HDDI) diesel engine. The spray penetration is investigated, firstly under quiescent conditions, injecting the fuel in a vessel under ambient temperature and controlled back pressure by both numerical and experimental analyses using the STAR-CD code and the imaging technique, respectively. Experimental results of fuel injection rate, fuel penetration, and spray cone angle are used as initial conditions to the code and for the comparison of predictions. The experimental investigation is carried out using a mechanical injection pump equipped by the heavy duty eight cylinder engine. Only one of its plungers has been activated and the fuel is discharged through a seven holes mechanical injector, 0.40 mm in diameter.
2005-04-11
Technical Paper
2005-01-1915
P. Ding, A. J. Buijk, W. A. van der Veen
The Adaptive Multiple Euler Domains technology in MSC.Dytran has been extended for the Multi-material Euler Solver. This paper demonstrates the application of this new method to the dynamics of fuel tank filling. The interest in applicability of MSC.Dytran to fuel tank filling originated from a major car manufacturer. The model includes both the fuel and the air inside the tank. The simulation process starts with properly initializing the fuel and air inside the tank under gravity loading. The fuel filling process will then be demonstrated, including the venting of air through a venting tube. The simulation is performed with MSC.Dytran.
Viewing 1 to 30 of 1489

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