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2011-04-12
Technical Paper
2011-01-0266
J.Y. Wong
With growing globalization of the economy, to gain a competitive edge in world markets shortening the product development cycle is crucial. Virtual product development is, therefore, being actively pursued in the off-road vehicle industry. To implement this process successfully, the development of comprehensive and realistic computer-aided methods for performance and design evaluation of off-road vehicles is of vital importance. To be useful to the engineer in industry for the development and design of new products, the computer-aided methods should take into account all major vehicle design parameters and pertinent terrain characteristics. They should be based on the understanding of the physical nature and the mechanics of vehicle-terrain interaction. Their capabilities should be substantiated by test data.
2011-04-12
Technical Paper
2011-01-0656
Jason A. Lustbader, John P. Rugh, Brianna R. Rister, Travis S. Venson
In the United States, intercity long-haul trucks idle approximately 1,800 hrs per year primarily for sleeper cab hotel loads, consuming 838 million gallons of diesel fuel [1]. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is working on solutions to this challenge through the CoolCab project. The objective of the CoolCab project is to work closely with industry to design efficient thermal management systems for long-haul trucks that keep the cab comfortable with minimized engine idling. Truck engine idling is primarily done to heat or cool the cab/sleeper, keep the fuel warm in cold weather, and keep the engine warm for cold temperature startup. Reducing the thermal load on the cab/sleeper will decrease air conditioning system requirements, improve efficiency, and help reduce fuel use. To help assess and improve idle reduction solutions, the CoolCalc software tool was developed.
2011-04-12
Technical Paper
2011-01-0240
Saurav Talukdar, Salil Kulkarni
The planar rigid bicycle model is one of the most popular models used in vehicle dynamics. It has widely been used in studying vehicle handling characteristics and designing steering control system for vehicles. This paper analyses a modified dynamic model called the "Elastic Bicycle Model." This model improves upon the classical bicycle model by taking into account the flexibility of the vehicle frame by using concepts from the Euler beam theory. Complete set of the resulting dynamic equations of this model are presented. Non-dimensional versions of the equations are used to investigate the steady state response of the model. Finally, the results of the response study obtained by modeling a small truck with an elastic model and the classical bicycle model are presented. These include the steady state solutions as function of different parameters as well as a transient solution in response to a saw-tooth steering input and a step input. Octave® has been used for simulation purpose.
2011-04-12
Journal Article
2011-01-0178
Jeff Howell
Vehicles on the road operate in the turbulent flow field resulting from the combined effects of the natural wind and the wakes of other vehicles. While substantial data exists on the properties of the natural wind, much less information is available for the wake properties of road vehicles. The wake information available for road vehicle shapes is mainly restricted to the near wake region, but to understand the vehicle operating environment it is the wake downstream of this region which is of interest. To determine the range of this area of interest requires some knowledge of the decay of the wake properties. From wind tunnel studies using small simple bluff bodies in free stream and in ground proximity the principle wake properties, velocity deficit and peak turbulence intensity have been measured. The maximum velocity deficit is shown to approximately decay with x-2/3, where x is the distance downstream, while turbulence intensity decays at a slightly slower rate.
2011-04-12
Technical Paper
2011-01-0191
Edoardo Sabbioni, Silvia Negrini, Francesco Braghin, Stefano Melzi lng
The paper investigates the interaction between soil and tractor tires through a 2D numerical model. The tire is schematized as a rigid ring presenting a series of rigid tread bars on the external circumference. The outer profile of the tire is divided into a series of elements, each one able to exchange a normal and a tangential contact force with the ground. A 2D soil model was developed to compute the forces at the ground-tire interface: the normal force is determined on the basis of the compression of the soil generated by the sinking of the tire. The soil is modeled through a layer of springs characterized by two different stiffness for the loading (lower stiffness) and unloading (higher stiffness) condition. This scheme allows to introduce a memory effect on the soil which results stiffer and keeps a residual sinking after the passage of the tire. The normal contact force determines the maximum value of tangential force provided before the soil fails.
2011-04-12
Journal Article
2011-01-0162
Ming Jiang, Huaizhu Wu, Kebing Tang, Minsuk Kim, Sivapalan Senthooran, Heinz Friz, Yingzhe Zhang
The engineering process in the development of commercial vehicles is facing more and more stringent emission regulations while at the same time the market demands for better performance but with lower fuel consumption. The optimization of aerodynamic performance for reduced drag is a key element for achieving related performance targets. Closely related to aerodynamics are wind noise and cabin soiling and both of them are becoming more and more important as a quality criterion in many markets. This paper describes the aerodynamic and aero-acoustic performance evaluation of a Dongfeng heavy truck using digital simulation based on a LBM approach. It includes a study for improving drag within the design of a facelift of the truck. A soiling analysis is performed for each aerodynamic result by calculating the accumulation of particles emitted form the wheels on the cabin. One of the challenges in the development process of trucks is that different cabin types have to be designed.
2011-04-12
Technical Paper
2011-01-0109
Flavio Cimolin, Michele Rabito, Andrea Menotti
A complete methodology for the thermo-mechanical analysis of optical devices for the automotive industry is presented. The objective is to predict the thermal field all over the lamp, highlighting the zones with risk of melting, and the deformations and stresses associated with it. The proposed approach is based on a Computational Fluid-Dynamic (CFD) simulation capable of capturing all the heat transfer phenomena occurring inside and outside the lamp: conduction between different components of the device, natural convection associated with density changes in air (buoyancy effects), and radiation heat transfer. The latter requires a fairly complex modeling strategy in order to provide a satisfactory (and conservative) treatment for the source of power, i.e. the filament, which can be obtained by means of a proper inclusion of transparency.
2011-04-12
Technical Paper
2011-01-0118
Daniel Le Messurier, John S. Orisich
Monte Carlo simulations are shown to be a useful tool when determining the flux output of LED arrays during the design phase. The results of Monte Carlo simulations are able to show the statistical distribution of output flux based on multi-LED arrays, thus allowing engineers to optimise their design, rather than using worst case scenario design principles.
2011-04-12
Technical Paper
2011-01-0651
Joshua Pryor, Matt Pierce, Eric Fremond, Yanick Michou
This paper presents the efforts done by Volvo 3P, through a partnership with ThermoAnalytics Inc, to develop transient thermal simulation methodologies of the under hood of a truck. The verification process for the hot spots analysis currently in use at Volvo 3P is described and the key transient situations for the hot spots analysis are identified: hot shutdown, DPF regeneration and long drive cycle, are currently only covered by physical testing late in the project, contrary to steady-state operating conditions that are already managed through simulations in the early stage of the development phase. The goal of this work is to develop simulation methodologies for these transient situations which are likely to increase the efficiency of the verification process. The key issues to be satisfied are to minimize the model development and the simulation times while achieving an acceptable accuracy level.
2013-09-24
Technical Paper
2013-01-2417
Lisa Henriksson, Erik Dahl, Peter Gullberg, Lennart Lofdahl
This paper presents results and a Computational Fluid Dynamics (CFD) method for simulation of a detailed louvered fin for a multi-louvered compact heat-exchanger. The airflow was angled at 90°, +30° and −30° relative to the heat-exchanger to evaluate changes in static pressure drop and airflow characteristics. The investigation was based on three heat-exchangers with thicknesses of 52mm and two of 19mm. One period of a detailed louvered fin was simulated for two airflows for each heat-exchanger. The pressure drop data was thereafter compared to experimental data from a full-size heat-exchanger. From the pressure drop and the airflow characteristic results recommendations were made that those kinds of simulations could be defined as steady state, and with the kω-SST turbulence model. For the same heat-exchanger angle the airflow within the core was similar, with a turbulent characteristic behind it.
2014-01-15
Journal Article
2013-01-9091
Dongfang Jiang
To get a sequence retainable rainflow cycle counting algorithm for fatigue analysis, an alternate equivalent explanation to rainflow cycle counting is introduced, based on which an iterative rainflow counting algorithm is proposed. The algorithm decomposes any given load-time history with more than one crest into three sub-histories by two troughs; each sub-history with more than one crest is iteratively decomposed into three shorter sub-histories, till each sub-history obtained contains only one single or no crest. Every sub-history that contains a single crest corresponds to a local closed (full) cycle. The mean load and alternate load component of the local cycle are calculated in parallel with the iterative procedure.
2013-09-08
Technical Paper
2013-24-0150
Georgios Fontaras, Martin Rexeis, Panagiota Dilara, Stefan Hausberger, Konstantinos Anagnostopoulos
Following its commitment to reduce CO2 emissions from road transport in Europe, the European Commission has launched the development of a new methodology for monitoring CO2 emissions from heavy-duty vehicles (HDV). Due to the diversity and particular characteristics of the HDV sector it was decided that the core of the proposed methodology will be based on a combination of component testing and vehicle simulation. A detailed methodology for the measurement of each individual vehicle component of relevance and a corresponding vehicle simulation is being elaborated in close collaboration with the European HDV manufacturers, component suppliers and other stakeholders. Similar approaches have been already adopted in other major HDV markets such as the US, Japan and China.
2013-09-08
Journal Article
2013-24-0016
Daniele Farrace, Michele Bolla, Yuri M. Wright, Konstantinos Boulouchos
Numerical simulations of in-cylinder soot evolution in the optically accessible heavy-duty diesel engine of Sandia National Laboratories have been performed with the multidimensional conditional moment closure (CMC) model using a reduced n-heptane chemical mechanism coupled with a two-equation soot model. Simulation results are compared to the high-fidelity experimental data by means of pressure traces, apparent heat release rate (AHRR) and time-resolved in-cylinder soot mass derived from optical soot luminosity and multiple wavelength pyrometry in conjunction with high speed soot cloud imaging. In addition, spatial distributions of soot relevant quantities are given for several operating conditions.
2013-09-24
Technical Paper
2013-01-2398
Mahendra Muli, Jace Allen
The Model-Based Development (MBD) process has been the key enabler of technical advancement. MBD helps manage complexity, while making product development faster by bringing clarity and transparency to the entire product development process, specifically software components. Developing software using MBD has required extensive, sophisticated toolchains, like the ones provided by dSPACE, that allow for efficient rapid controls prototyping, automatic code generation, and advanced validation and verification techniques with hardware-in-the-loop (HIL) test systems. MBD is an efficient iterative process that allows engineers to improve quality and deliver on demanding needs of product variants in the current competitive environment. However, the MBD process described commonly using the ‘V-Cycle’ diagram leads to the generation of large volumes of data artifacts and work products. The iterative process, variants and versions of these artifacts lead to even larger amounts of data.
2013-09-24
Technical Paper
2013-01-2404
Mahendra Muli, Joe Cassar
It is not news anymore when somebody talks about increasing software content in today's vehicles, transportation systems and machinery. The software content and complexity has grown so tremendously and rapidly that even the most advanced product/software development techniques leave more to desire in view of evolving product life-cycles, feature content and need for development efficiency. Model-Based Design (MBD) techniques and V-Cycle based development processes address the significant need for managing complexity, and to some extent, efficiency in product development. Further efficiency in the development process can be achieved by enabling virtual validation of software components. The virtual validation environment for software not only has the ability to run the software component as a standalone unit for performance validation, but is also extended to the validation of the performance of the entire embedded software of an ECU, multiple ECUs and the entire system.
2013-09-24
Technical Paper
2013-01-2381
Shannon K. Sweeney
This paper presents a simple method of estimating steady-state diesel engine disturbance amplitudes that can be used in rigid-body, low frequency vibration modeling to predict the performance of an engine's isolation suspension and its components. The internal disturbances occurring at each cylinder and crank throw are determined and combined to provide the net disturbances for several common four-stroke diesel engine configurations. The method utilizes a simplified Fourier decomposition of diesel combustion and the predominant inertia disturbances from within the engine. With a few pieces of information from the engine maker, actual disturbance amplitudes and phases can be estimated. Conditions and simplifying assumptions are discussed. The estimated disturbance amplitudes can also be used in torsional vibration modeling of the drivetrain.
2013-09-24
Technical Paper
2013-01-2368
Harish Harinarayanan
Commercial vehicle payload depends on the client for which the vehicle fleet owner is operating. Load carriers like flatbed trailer offer the flexibility to be loaded with a large number of light payloads or a few numbers of massive payloads. Such load carriers have to be evaluated for various possibilities of loading patterns that could happen in the market. The objective of this work is to evaluate flatbed trailer for its structural strength for different customer application cases, using computer simulation. Structural load cases due to payloads like containers, steel coils and cement bags are arrived at. Static structural analysis using MSC Nastran is performed to evaluate for the worst customer loading pattern from structural stress point of view. This paper also describes a simplified method for simulating the effect of trailer suspension, tractor suspension and the fifth-wheel coupling in the analysis whose detailed modeling is not possible at the concept level.
2013-09-24
Technical Paper
2013-01-2352
Paul C. Niglas
The new RSDII (Reduced Stopping Distance, phase 2) regulation creates an increased emphasis by the heavy truck industry to ensure that brake systems are properly chosen and optimized. This regulation has led to vehicles being fitted with much more powerful brakes. However, despite the intent of these new brakes to provide larger braking forces for shorter stopping distances, the performance of vehicles is still limited by the maximum friction coefficient between the vehicle's tires and the road. In order to get the most out of these new brakes, it is essential that the entirety of the vehicle be taken into account. With the use of a hardware-in-the-loop simulation tool, this paper will present stopping data predictions from a variety of vehicles of varying brake torque and wheelbase. It will be shown how these factors change the way a vehicle behaves under panicked stopping situations.
2004-03-08
Technical Paper
2004-01-1588
Adam B. Cooper, Michael Kokkolaras, Panos Y. Papalambros
Developing a new technology requires decision-makers to understand the technology's implications on an organization's objectives, which depend on user needs targeted by the technology. If these needs are common between two organizations, collaboration could result in more efficient technology development. For hybrid truck design, both commercial manufacturers and the military have similar performance needs. As the new technology penetrates the truck market, the commercial enterprise must quantify how the hybrid's superior fuel efficiency will impact consumer purchasing and, thus, future enterprise profits. The Army is also interested in hybrid technology as it continues its transformation to a more fuel-efficient force. Despite having different objectives, maximizing profit and battlefield performance, respectively, the commercial enterprise and Army can take advantage of their mutual needs.
2004-03-08
Technical Paper
2004-01-1690
Michael Temkin, David Santi, Lawrence Black, James Tindall
During the initial vehicle design phase and as the first prototypes are built, extensive on-board instrumentation and data acquisition is required at the proving grounds (PG). The data is used for various types of testing and analysis. During this phase of development very few parts and assembly components are available for physical test. The objective is to develop a component test for the truck box. This test can be run without suspension parts during the early stages of the vehicle development. A further objective is to correlate the test to FEA models and actual Proving Ground full vehicle test results.
2004-03-08
Technical Paper
2004-01-1222
Scott Kimbrough
Monte Carlo simulation is used to determine the likelihoods of competing scenarios offered by opposing parties involved in a motor vehicle accident. A case study is presented in which there is a dispute among the parties about who passed who first. It is shown that even though both scenarios are possible, one of the scenarios has a much greater likelihood. Besides demonstrating how Monte Carlo simulation provides probability information that can be used to weigh the likelihood of competing scenarios, the case study also provides another example of how Monte Carlo simulation can dig information out of the evidence surrounding an accident that cannot be obtained by other methods.
2004-03-08
Technical Paper
2004-01-1191
Marcus Hiemer, Sebastian Lehr, Uwe Kiencke, Takanori Matsunaga
The reproduction of the vehicle motion is a crucial element of accident reconstruction. Apart from the position of the center of gravity in an inertial coordinate system, the vehicle heading plays an important role. The heading is the sum of the yaw angle and the vehicle body side slip angle. In standard vehicles, the yaw angle can be determined using the yaw rate sensor and the wheel speeds. However, the yaw rate sensor is often subject to temperature drift. The wheel speed signals are forged at low speeds or due to slip. These errors result in significant deviations of reconstructed and real vehicle heading. Therefore, an intelligent combination of these signals is required. This paper describes a fuzzy system which is capable to increase the accuracy of yaw angle calculation by means of fuzzy logic. Before the data is applied to the fuzzy system, it is preprocessed to ensure the accuracy of the fuzzy system inputs.
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
2004-01-0923
E. G. Pariotis, D. T. Hountalas
This work is a part of an extended investigation conducted by the authors to validate and improve a newly developed quasi-dimensional combustion model. The model has been initially applied on an old technology, naturally aspirated HSDI Diesel engine and the results were satisfying as far as performance and pollutant emissions (Soot and NO) are concerned. But since obviously further and more extended validation is required, in the present study the model is applied on a new technology, heavy-duty turbocharged DI Diesel engine equipped with a high pressure PLN fuel injection system. The main feature of the model is that it describes the air-fuel mixing mechanism in a more fundamental way compared to existing multi-zone phenomenological combustion models, while being less time consuming and complicated compared to the more accurate CFD models. The finite volume method is used to solve the conservation equations of mass, energy and species concentration.
2004-10-26
Technical Paper
2004-01-2673
Jean-Claude Ossyra, Monika Ivantysynova
A new control concept was developed to minimize the power losses of a hydrostatic drive line for off-road vehicles. The drive line control concept is based on two separate closed loop controls, one for the hydrostatic transmission and another for the combustion engine. The command values for both control loops are calculated under consideration of the characteristic curves of the combustion engine and the losses within the hydrostatic transmission, using an on-line optimization procedure. This paper discusses the benefits of this control concept based on a comparison of typical realistic driving manoeuvres. Objective of the investigations for different output powers is the potential of fuel savings under different operating conditions. A hardware-in-the-loop test rig for the investigated hydrostatic propel drive is used for the experimental validation.
2004-10-26
Technical Paper
2004-01-2714
Katrin Strandemar, Boris Thorvald
This paper presents the ride diagram, a new way of evaluating and presenting ride comfort Furthermore, a simplified methodology is suggested to test and correlate objective measures of vehicle ride with subjective driver impressions. The ride diagram is calculated from measured cab accelerations resulting from increased levels of excitation. The basic idea is to graphically visualize how ride comfort changes with excitation. Test drivers are then asked to pair the set of tested vehicles with corresponding curves in the ride diagram. This step assures that the selected measure captures how drivers apprehend changes in vehicle ride. The suggested methodology is illustrated on trucks with different cab suspension settings. For a given test track increased vehicle speed is used to increase the excitation level. The trucks are also placed in a road simulator to enable easy variation of both excitation type and level.
2004-10-26
Technical Paper
2004-01-2688
Dogan San, Ergun Guraslan, Omer Rustu Ergen, Korhan Kanar
FORD OTOSAN has developed a new heavy-duty diesel engine, ECOTORQ, for the new Ford Cargo Trucks whose production started in September 2003. The engine is 7.3 liters, 6-cylinder in-line, with common rail fuel injection system and overhead camshaft design having 4 valves per cylinder. The engine meets the Euro-III exhaust emissions limits, which were in effect when it was introduced, and the engine incorporates the potential to meet Euro-IV. Modern computation and simulation methods were used and extensive experimental studies were made during the design and development stages, which helped reach the targets of compactness, modular structure, low fuel consumption, low noise level and low emissions.
2004-10-26
Technical Paper
2004-01-2694
Stefano J. Cassara, David C. Anderson, J. Magnus Olofsson
The accurate prediction of commercial-vehicle ride and handling performance with computer simulation tools is dependent on the level of correlation between the computer model and experimental data. Correlating vehicle attributes to physical test data is often challenging due to the large number of degrees of freedom - and, correspondingly, the large number of tunable parameters - typically required to accurately model vehicle behavior. A high level of interaction between input parameters and vehicle attributes further complicates the task. As a result, this type of correlation is a multi-objective optimization exercise in which the judicious planning of supporting test activity is critical to achieving the right level of model accuracy with an acceptable amount of resource investment. This paper discusses the methodology implemented in the validation of a tractor-semitrailer ADAMS model for both ride and handling simulations and presents the results obtained.
2004-10-26
Technical Paper
2004-01-2667
Timothy J. Milburn
Product development and manufacturing organizations are moving from the traditional, multiple and serial design-build-test cycle approach to an integrated, concurrent task and systems engineering paradigm, led by upfront planning, analysis and simulation, supported by credible product test data. This “paradigm shift” includes a move from a predominance of physical testing for product prototype validation to simulation-led problem solving and performance validation, using Computer Aided Engineering, and Design (CAE and CAD) tools. Supported by use of Computer Aided Testing (CAT), physical testing capabilities have comparably grown in accuracy and application range. The role of testing is moving from mostly pre-production validation to include support of product design decisions throughout the development process, including upfront planning.
2004-10-26
Technical Paper
2004-01-2658
William Wangard, Aleksandra Egelja, Hossam Metwally
A transient, 3-dimensional, continuum CFD model of soot loading and regeneration has been developed for a single channel unit in a diesel particulate filter. The detailed model is used to predict the soot loading, velocity, temperature, and species distributions in both the air channels and porous walls of the filter. The simulation is performed in two phases: loading and regeneration. In the loading phase, soot profiles are estimated for a clean filter using a steady-state simulation. In the second phase, transient regeneration is modeled using a single-step, irreversible heterogeneous mechanism is used to predict the formation of carbon monoxide and carbon dioxide products during the regeneration process, incorporating a fractionization scheme. Reaction rates are predicted via an Arrhenius rate law, but may be tempered due to diffusion-limiting conditions in the porous reaction zone. Simulations are performed with a commercial CFD package and user-defined functions.
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