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Viewing 1 to 30 of 170911
2004-03-08
Technical Paper
2004-01-1199
Timothy J. Reust
Many newer commercial vehicles have an event data recorder (EDR) that can record pre-event and post-event speeds. The EDR is incorporated into the engines electronic control module (ECM). In this study, the accuracy of the ECM-reported speed was tested during acceleration, gear shifting and braking at speeds between 16 and 88 km/h (10 to 55mph). The ECM-reported speed was compared to the speed measured by a calibrated optical 5th wheel. The results showed that the accuracy of the ECM-reported speed matched closely during acceleration, cycled to periods of under-reporting the speed during hard braking due to the ABS brake function, briefly under-reporting the speed after letting off the throttle for braking or gear shift and briefly over-reporting the speed near the end of a gear shift phase. This study also looked at calibration factors of the ECM and their effect on the ECM-reported speed.
2004-03-08
Technical Paper
2004-01-1158
Gholam-Reza Vossoughi, Siavash Rezazadeh
In this paper, development of a MATLAB-based computer environment for optimization of EMS calibration is presented. The objective is to eliminate the complicated and tedious calibration process on chassis dynamometer or at least reduce the time required. In this way, first a black-box model of engine is developed. Then this model is linked to ADVISOR -the renowned vehicle simulation software- to obtain an integrated engine-driveline model. This model is used in the optimization process, which includes different optimization techniques.
2004-03-08
Technical Paper
2004-01-1207
Terry D. Day
SIMON is a new 3-dimensional vehicle dynamic simulation model. The capabilities of the model include non-linear handling maneuvers and collision simulation for one or more vehicles. As a new model, SIMON must be validated by comparison against actual handling and collision experiments. This paper provided that comparison. Included in the validation were lane-change maneuvers, alternate ramp traversals, limit maneuvers with combined braking and steering, vehicle-to-vehicle crash tests and articulated vehicle handling tests. Comparison against other models were included. No metric was provided for handling test comparisons. However, statistical analysis of the collision test results revealed the average path range error was 6.2 to 14.8 percent. The average heading error was -4.7 to 0.7 percent. Delta-V error was -1.6 to 7.5 percent. VEHICLE SIMULATION has many uses in the vehicle design and safety industries.
2004-03-08
Technical Paper
2004-01-1156
Fabien Muradore, Thomas Dreher, Sophie Jan
Wipe quality of wiper systems is influenced not only by the definition of the wiper system, but also by the shape of the glass. In order to optimize the overall performance of the system, Valeo Wiper Systems has developed an optimization algorithm, which is based on geometrical criteria. The multi-criteria objective not only considers wipe quality but also constraints by glass feasibility and respect of optical standards. As the direct derivation of the objective functions is not available, a neural network approximation is used at the place of the real function. A neural network with several outputs enables the engineer to include his knowledge in the optimization loop by changing disciplinary weights.
2004-03-08
Technical Paper
2004-01-1155
Yuejun E. Lee, Derrick R. Black
Multi-piece propshaft design during a customer's request for quote (RFQ) process has proven to be a great challenge for supplier engineers. This challenge requires a good balance of design quality and fast response time in order to meet customer expectations. Failing to do so may lead to either increased development cost due to late design changes or loss of the opportunity resulting from missed deadlines or a lack of design definition. After receiving all of the customer's requirements, the iterative design process normally takes a minimum of one to two weeks. During this period, supplier engineers must perform many trade-off analyses by adjusting more than one dozen design variables to satisfy various design criteria. Typically, this is accomplished by manually adjusting design variables to search for an acceptable design using tools such as Microsoft Excel.
2004-03-08
Technical Paper
2004-01-1153
Xiaolin Hu, Zhongfan Wang, Lianying Liao
How to match various components of the Hybrid Electric Vehicle (HEV) and manage the energy distribution is critical for HEV design and control considering that there are at least two sets of energy output systems, the fuel converter (engine or fuel cell) and the energy storage system (battery stack). It is an optimization issue. Much work has been done in this field but a significant portion optimizes the component sizes and control strategy parameters separately. What's more, most work concerns single objective optimization although more than one objective is more common and natural in HEV optimization. This paper uses an advanced soft computing technique, Non-dominated Sorting Genetic Algorithm (NSGA-II), one of the most efficient Multi-Objective Evolutionary Algorithms (MOEAs), to optimize a parallel HEV's fuel economy and emissions including HC, CO, and NOx emissions simultaneously, instead of converting them into a single objective.
2004-03-08
Technical Paper
2004-01-1163
Shinji Fujii, Takayuki Sunakawa, Akiko Abe, Masanobu Fukushima, Kenji Kawaguchi, Shigeru Ogawa
This paper clarifies aggressivity reduction approach for MPV, Multi-Purpose Vehicles, derived from large passenger vehicles toward small passenger vehicles. The effects of aggressivity-reducing approach were measured through full-frontal rigid barrier crash simulations with TRL aluminum honeycomb by Finite Element Method. The front-end structures of large vehicles studied in this paper based on this aggressivity reduction approach show good front-end homogeneity and low average height of force. The structures were also found to effectively reduce aggressivity toward small vehicles by car-to-car simulation. However, there are some cases where the effect was influenced by overlap ratios. From this result, overlap ratio is considered to be one of the important factors to improve compatibility performance.
2004-03-08
Technical Paper
2004-01-1162
Satoshi Takizawa, Eisei Higuchi, Tatsuo Iwabe, Tomiji Sugimoto, Takayuki Kisai, Takayuki Suzuki
This paper investigates test procedures for vehicle frontal crash compatibility. Both Full Width Deformable Barrier (FWDB) tests and Moving Deformable Barrier (MDB) tests were studied to assess relevant factors of compatibility issues. The FWDB test with load cells was examined to evaluate the stiffness and interaction areas of vehicles (sometimes referred to as the “aggressivity” of vehicles). Compatibility metrics were computed using barrier load cell data and the output from the FWDB test was compared with that from the Full Width Rigid Barrier (FWRB) test. Since the results obtained from these two full width tests were considerably different, a full frontal vehicle-to-vehicle test was carried out to identify structural deformation modes. The results indicated that similar deformation modes were observed between the vehicle-to-vehicle test and the FWDB test.
2004-03-08
Technical Paper
2004-01-1161
Edmond L. Toy
Crashes involving two passenger vehicles account for 25% of all traffic fatalities in the United States. Large differences in the weight of the crash-involved vehicles can have a strong influence on injury and fatality risks in both vehicles. A simple, spreadsheet-based model is developed to examine empirically the distribution of mass in the on-road fleet of passenger vehicles from 1975 to 2001. The model relies on publicly available data to compute an index of mass variance. The results indicate that mass variance decreased substantially beginning in 1975, during the start of a period of significant downweighting of new cars. The variance reached a minimum in 1996 and has been increasing since then. Simulations were conducted to examine the frequency of hypothetical crashes involving large disparities in vehicle mass. The fraction of crashes in which the mass ratio (heavier vehicle to lighter vehicle) was 1.75 or greater was 6% in 1975, 1% in 1996, and 2% in 2001.
2004-03-08
Technical Paper
2004-01-1160
Deng Xiaolong, Zhang Zongjie, Zhao Xinze
The result of rib stiffening is the redistribution of natural frequencies and mode shapes of the plate, which can significantly alter its noise and vibration character. In this paper, genetic algorithms are used as a promising tool for sound radiation minimization problems. The objective of the study is to determine effective, general design methods for determining the optimal dimensions of the stamped rib in a plate to minimize the total radiated acoustic power. Acoustic response under broad-band excitation is considered. Radiated sound power is calculated using a boundary element method, in conjunction with a finite element solver for the solution of the structural problem.
2004-03-08
Technical Paper
2004-01-1168
Guy S. Nusholtz, Lan Xu, Yibing Shi, Laura Di Domenico
The effects of vehicle “stiffness” and mass on the occupant response during a crash may be determined by evaluation of accident data. However, “stiffness” and mass may be correlated, making it difficult to separate their effects. In addition, a single-valued “stiffness”, although well defined for linear case, is not well defined for non-linear systems, such as in vehicle crash, making the separation task even more difficult. One approach to addressing the lack of a clear definition of stiffness is to use multiple definitions. Each stiffness definition can then be correlated with mass to look for trends. In this study, such an approach was taken, and the different stiffness definitions were given and their values were obtained from rigid barrier crash test data. No clear relationship between mass and stiffness appears to exist. All the stiffness measures reviewed show, at best, only a weak correlation with mass. A stiffness analysis among different vehicle types was also carried out.
2004-03-08
Technical Paper
2004-01-1167
Dietmar Haenchen, Thomas Schwarz, Gareth Thomas, Robert Zobel
Compatibility has been a research issue for many years now. It has gained more importance recently due to significant improvements in primary and secondary safety. Using a rigorous approach, combining accident research and theoretical scientific considerations, measures to improve vehicle-vehicle compatibility, with an emphasis on feasibility, were discussed. German accident research statistics showed that frontal impacts are of higher statistical significance than side impacts. Based on this and the high potential for improvement due high available deformation energy, the frontal impact configuration was identified as the most appropriate collision mode for addressing the compatibility issue. In side impacts, accident avoidance was identified as the most feasible and sensible measure. For frontal vehicle-vehicle impacts, both trucks and passenger cars were identified as opponents of high statistical significance.
2004-03-08
Technical Paper
2004-01-1166
Brian O'Neill, Sergey Y. Kyrychenko
2004-03-08
Technical Paper
2004-01-1165
M. K. Verma, R. Nagappala, Y. J. Tung, M. R. Zimmerman, M. Murugan, T. A. Bernstein
The concept of height of force has been suggested by some researchers as one possible parameter defining the structural interaction probability between vehicles of different sizes. This proposed parameter was defined as the vertical centroid of forces exerted on a flat barrier surface when a vehicle crashes into the barrier. It is therefore measured as a function of elapsed time since crash. In this paper, the height of force is obtained from theoretical calculations and also measured in crash tests at 56 km/h against barriers instrumented with an array of load cells. It is observed that the measured values of height of force have significant errors which are dependent on factors other than the crash conditions and the properties of the vehicle's structure and geometry. These factors need to be taken into account in future discussions of using the height of force or the average height of force as an indicator of vehicle compatibility.
2004-03-08
Technical Paper
2004-01-1173
Hui Wang, Zheng-Dong Ma, Noboru Kikuchi, Christophe Pierre, Basavaraju Raju
A multi-domain and multi-step topology optimization approach has been developed to address a wide range of structural design problems with manufacturability and other application concerns. The potential applications have been demonstrated in our previous work [1,2]. In this paper, we try to extend this method for vehicle crash design problem. The design process will be explained and examples will be provided to illustrate the potential application of this method for complicated crash design problems.
2004-03-08
Technical Paper
2004-01-1172
Leonard Evans
About the most firmly established vehicle-safety effect is that the heavier the vehicle, the lower are the risks to its occupants. Empirically data show that the additional mass of a passenger reduces driver fatality risk by 7%. While occupants of heavier vehicles enjoy increased safety, there are two important negatives associated with heavier vehicles. First, they increase risk to occupants of other vehicles into which they crash. Second, they consume more fuel. The size, or length, of a vehicle also affects safety. All other factors, including mass, being equal, a larger vehicle reduces fatality risk to its occupants. But unlike mass, it also reduces risk to occupants in vehicles into which it crashes. A quantitative relationship expressing fatality risk as a function of the mass and size of both cars involved in a two-car crash was derived in Causal influence of car mass and size on driver fatality risk, Am J Pub Health. 91:1076-81;2001.
2004-03-08
Technical Paper
2004-01-1171
Pascal Delannoy, Jacques Faure, Donat Coulombier, Richard Zeitouni, Tiphaine Martin
After a lot of researches in the field of compatibility through testing and accident analysis, the current knowledge allows us to propose a new test protocol able to control the two issues of compatibility: partner and self protection. In other words, the procedure would be able to assess the most relevant parameters: structural interaction (geometry / stiffness) and compartment strength (stiffness). The most effective way to meet this target is to control both of them at the same time, thus avoiding many test regulations. The new final protocol will be a mix of two very well known test configurations: current frontal regulation in Europe (ECE 94) to assess compartment strength and structural integrity through vehicle and dummy criteria Progressive Deformable Barrier test (PDB) to assess and control force distribution through barrier deformation.
2004-03-08
Technical Paper
2004-01-1134
Jae Su Kim
In the analysis of the converter canning process, there have been a lot of progresses in stress prediction for the converter shell and mat pressure. However, stress prediction for the substrate, which is the most critical for the converter durability, has been less studied in the finite element analysis approach. Substrate is made of a lot of cell structure with thin walls. Ideally, it is preferred to mesh the every single wall with solid elements to have a better analysis prediction. However, due to the limited computer resources, it is difficult to create it with detail model because it needs a lot of elements. In this paper, the stress in the substrate during the canning process for the clamshell and tourniquet type is predicted based on the equivalent orthotropic solid element. A detailed cell for ceramic substrate and coating is modeled with enough solid elements to represent coating fillet radius.
2004-03-08
Technical Paper
2004-01-1169
James W. Saunders, Shashi Kuppa, Aloke Prasad
The National Highway Traffic Safety Administration (NHTSA) is conducting a research program to investigate the use of the 40 percent offset deformable barrier (ODB) crash test procedure to reduce death and injury, in particular debilitating lower extremity injuries in frontal offset collisions. This paper presents the results of 22 ODB crash tests conducted with 50th percentile male and 5th percentile female Hybrid III (HIII) dummies fitted with advanced lower legs, Thor-Lx/HIIIr and Thor-FLx/HIIIr, to assess the potential for debilitating and costly lower limb injuries. This paper also begins to investigate the implications that the ODB test procedure may have for fleet compatibility by evaluating the results from vehicle-to-vehicle crash tests.
2004-03-08
Technical Paper
2004-01-1135
S. T. Gulati, S. Widjaja, W. Xu, D. R. Treacy, J. A. Yorio
This paper provides elastic analysis of compressive stresses in the matrix and skin regions of automotive substrates during 3D- and 2D-isostatic strength testing. The matrix region is treated as transversely isotropic material and the skin region as isotropic material, each with their independent elastic properties. Such a solution helps quantify load sharing by the matrix and skin regions which, in turn, affect compressive stresses in each region. The analysis shows that the tangential compressive stresses in the skin and matrix differ significantly at the interface due to high stiffness ratio of skin versus matrix. The resulting strain in the skin is more severe for thin and ultrathin wall substrates and may lead to localized bending of interfacial cells thereby inducing premature failure. Methods to reduce compressive strain in both the matrix and skin without affecting performance-related advantages are discussed.
2004-03-08
Technical Paper
2004-01-1132
Bernhard J. Peters, Roland J. Wanker, Andreas Münzer, Johann C. Wurzenberger
Abstract Future limits on emissions for both gasoline and Diesel engines require adequate and advanced systems for the after-treatment of the exhaust gas. Computer models as a complementary tool to experimental investigations are an indispensable part to design reliable after-treatment devices such as catalytic converters and Diesel particulate filters including their influence on the power-train. Therefore, the objective of this contribution is to present an integrated 1D to 3D simulation workflow of of catalytic converters and Diesel particulate filters. The novelty of this approach is that parameters or set of parameters, obtained by a fast and efficient 1D-gas exchange and cycle simulation code for power-trains (AVL (2002a)), are readily transferable onto a 3D general purpose simulation code (AVL (2002b)). Thus, detailed aspects such as spatial distribution of temperatures or heat losses are investigated with only a single effort to estimate parameters.
2004-03-08
Technical Paper
2004-01-1133
Athanasios G. Konstandopoulos, Evdoxia Kladopoulou
A major challenge in the development of diesel filter systems is the selection of the appropriate filter medium in terms of its geometric configuration (cell density, wall thickness) and its physical properties (porosity, pore size). This selection aims to achieve minimization of the filter pressure drop as well as more efficient filter regeneration. The aim of the present work is to provide engineering criteria to support the design and selection of suitably sized wall-flow monolithic filters for diesel particulate control.
2004-03-08
Technical Paper
2004-01-1140
Zhihuang Dai, Michael J. Scott, Zissimos P. Mourelatos
Robust design is a methodology for improving the quality of a product or process by minimizing the effect of variations in the inputs without eliminating the causes of those variations. In robust design, the putative best design is obtained by solving a multi-criteria optimization problem, trading off the nominal performance against the minimization of the variation of the performance measure. Because some existing methods combine the two criteria with a weighted sum or another fixed aggregation strategy, which are known to miss Pareto points, they may fail to obtain a desired design. To overcome this inadequacy, a more comprehensive preference aggregation method is implemented here into robust design. Three examples -- one simple mathematical example, one multi-criteria structure design example, and one automotive example -- are presented to illustrate the effectiveness of the proposed method.
2004-03-08
Technical Paper
2004-01-1141
Zhihuang Dai, Michael J. Scott, Zissimos P. Mourelatos
There are two sorts of uncertainty inherent in engineering design, the random and the epistemic. Random, or stochastic, uncertainty deals with the randomness or predictability of an event. It is well understood, easily modeled using classical probability, and ideal for such uncertainties as variations in manufacturing processes or material properties. Epistemic uncertainty deals with our lack of knowledge, our lack of information, and our own and others' subjectivity concerning design parameters. Epistemic uncertainty plays a particularly important role in the early stages of engineering design, when a lack of information about nominal values of parameters is much more important than potential variations in those parameters. Design reuse, or the design of product platforms, is an example in which epistemic uncertainty can play a crucial role in early design.
2004-03-08
Technical Paper
2004-01-1136
Joyce Smith Cooper
This paper presents an analysis of the recyclability of fuel cell power trains based on material flows for three PEM fuel cell stack designs. The analysis considers the compatibility of materials in recycling, the separability of recyclable materials, and the fraction of material that can be recycled cost effectively. The fuel cells are designed with graphite, stainless steel, and composite bipolar plates and the stacks, batteries, transmission, and supporting equipment are sized to replace an example IC power train. Recyclable material flows are estimated on the basis of material intensities for the fuel cell power trains and are compared to the flows for the IC vehicle.
2004-03-08
Technical Paper
2004-01-1144
Walter W. Olson, David He
Traditionally, reliability and risk analysis rested on the principles of probability theory as designers and engineers needed to know how often certain events would occur. However, there are events that must not occur, as occurrence would cause catastrophic loss. In this situation, probability theory under-predicts the possibility of failure. This paper addresses a method for analyzing designs for the possibility of events occurring which incorporates evidence theory.
2004-03-08
Technical Paper
2004-01-1145
F. Browand, M. Hammache
We demonstrate the interaction of two truck shapes in tandem. Both trucks experience a decreased drag coefficient from the interaction. The degree of drag saving depends strongly upon the drag coefficients of the model trucks in isolation, and upon how the two trucks are arranged. For the two simplest shapes-parallelepipeds with or without partial leading-edge rounding-the total drag saving can range from 10 percent to 40% at a spacing of 2√A (approximately 18 feet at full scale) depending upon whether the lead or the trail parallelepiped has rounding. These two shapes-blunt and rounded-have drag coefficients in isolation of 0.94 and 0.51 respectively, and probably bracket the savings to be obtained for all real truck geometries. Our realistic model trucks (with wheels and a gap between tractor and trailer serving to distribute the source of drag along the length of the truck) have drag coefficients in the range CD = 0.5-0.7, and the total drag saving is a more modest 15-20% at 2√A.
2004-03-08
Technical Paper
2004-01-1142
Jin Wang, Nickolas Vlahopoulos, David J. Gorsich
This paper presents the utilization of alternative correlation functions in the Kriging method for generating surrogate models (metamodels) for the performance of the bearings in an internal combustion engine. Originally, in the Kriging method an anisotropic exponential covariance function is developed by selecting optimal correlation parameters through optimization. In this paper an alternative nonparametric isotropic covariance approach is employed instead for generating the correlation functions. In this manner the covariance for spatial data is evaluated in a more straightforward manner. The metamodels are developed based on results from a simulation solver computed at a limited number of sample points, which sample the design space.
2004-03-08
Technical Paper
2004-01-1148
Emilia Bratschitsch, Günter Bischof, Anton Haas, Albert Kaltenhauser
A significant reduction of the aerodynamic drag can be achieved by the refinement of the vehicle underside. But the investigation of the aerodynamic effectiveness of underfloor panels in wind tunnels turns out to be a challenging task. For this reason on-road methods like coastdown analysis are frequently employed. Most of these advanced coastdown methods determine the coefficients of the total drag by fitting a mathematical model to the measured velocity data. This requires separate time consuming tests in the laboratory to measure the wheel and transmission losses. The objective of the presented work was the development of an analysis method, which enables a simpler and more practicable on-road determination of aerodynamic improvements. In this method the rolling resistance can be factored out by employing the conservation of energy as basic approach for the investigation of air drag differences.
2004-03-08
Technical Paper
2004-01-1143
Jin Wang, Nickolas Vlahopoulos, Zissimos P. Mourelatos, Omidreza Ebrat, Kumar Vaidyanathan
This paper presents the development of surrogate models (metamodels) for evaluating the bearing performance in an internal combustion engine. The metamodels are employed for performing probabilistic analyses for the engine bearings. The metamodels are developed based on results from a simulation solver computed at a limited number of sample points, which sample the design space. An integrated system-level engine simulation model, consisting of a flexible crankshaft dynamics model and a flexible engine block model connected by a detailed hydrodynamic lubrication model, is employed in this paper for generating information necessary to construct the metamodels. An optimal symmetric latin hypercube algorithm is utilized for identifying the sampling points based on the number and the range of the variables that are considered to vary in the design space.
Viewing 1 to 30 of 170911

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