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Viewing 91 to 120 of 36624
2011-09-13
Journal Article
2011-01-2272
Wolfgang Schweiger, Werner Schoefmann, Andrea Vacca
This paper presents a simulation model for the analysis of internal gear ring pumps. The model follows a multi domain simulation approach comprising sub-models for parametric geometry generation, fluid dynamic simulation, numerical calculation of characteristic geometry data and CAD/FEM integration. The sub-models are interacting in different domains and relevant design and simulation parameters are accessible in a central, easy to handle graphical user interface. The potentials of the described tool are represented by simulation results for both steady state and transient pump operating conditions and by their correlation with measured data. Although the presented approach is suitable to all applications of gear ring pumps, a particular focus is given to hydraulic actuation systems used in automotive drivetrain applications.
2011-09-13
Technical Paper
2011-01-2262
Vijay Kumar Kalia, Yogesh Pawar
The amount of software, computation and logic embedded into the vehicle systems is increasing. Testing of complex real time embedded systems using Hardware in Loop (HIL) simulations across different vehicle platforms has been a challenge. Data driven testing enables a qualitative approach to test these complex vehicle systems. It consists of a test framework wherein the test logic and data are independent of the HIL test environment. The data comprises variables used for both input values and output verification values. This data is maintained in a database or in the form of tables. Each row defines an independent test scenario. The entire test data is divided into three categories, High, Medium and Low. This feature gives the advantage of leveraging the same set of test data from Unit Level Testing phases to the Integration Test phase in the V-Cycle of software development. A data driven test approach helps the reuse of tests across vehicle platforms.
2011-09-13
Technical Paper
2011-01-2265
Christina Perdikoulias, Brad Sommerfeld
Model-Based Development (MBD) has become increasingly important in the development of embedded software for commercial vehicles. For MBD to be most effective, modeling must be a unified part of the system and software lifecycle. System and software lifecycle management processes and tools that encompass all phases of the product, from concept to end-of-life, are essential to meet today's business innovation and quality demands. In a typical MBD environment, changes to requirements, test cases, configurations, calibrations or the actual models aren't automatically and interactively linked to one another. Significant manual effort goes into tracking changes that affect engineering artifacts. The downstream effect of one seemingly small change has the potential to affect thousands of artifacts across a product's lifecycle, including model elements.
2011-09-13
Journal Article
2011-01-2264
Michael Peperhowe, Kusnadi Liem, Hagen Haupt
Real-time simulation of truck and trailer combinations can be applied to hardware-in-the-loop (HIL) systems for developing and testing electronic control units (ECUs). The large number of configuration variations in vehicle and axle types requires the simulation model to be adjustable in a wide range. This paper presents a modular multibody approach for the vehicle dynamics simulation of single track configurations and truck-and-trailer combinations. The equations of motion are expressed by a new formula which is a combination of Jourdain's principle and the articulated body algorithm. With the proposed algorithm, a robust model is achieved that is numerically stable even at handling limits. Moreover, the presented approach is suitable for modular modeling and has been successfully implemented as a basis for various system definitions. As a result, only one simulation model is needed for a large variety of track and trailer types.
2011-09-13
Journal Article
2011-01-2259
Brendan Chan, Ananda Pandy
Forward collision mitigation systems (FCMS) are becoming standard in passenger car vehicles with the current trend of safety technologies development. Currently, safety systems are on the road towards widespread acceptance in the commercial vehicle industry. Whereas the full Electronic Stability Control (ESC) system attempts to sense the states of the vehicle to assist the driver to maintain directional control of the vehicle, current FCMS attempts to sense the environment around the front of the vehicle and either warns the driver to react or intervenes by slowing down the vehicle autonomously. Some of the latest developments in FCMS for commercial vehicles will be discussed, together with an outlook of future systems. This study will also examine some of the common scenarios that forward collision mitigation systems can be beneficial in, especially for commercial vehicles. The scenarios will be investigated using Hardware-in-loop-simulation, and the results discussed.
2011-09-13
Technical Paper
2011-01-2261
Jace Allen, Amanjot Dhaliwal, Jeff Warra
Currently, Hardware-In-the-Loop (HIL) testing is the defacto standard for ECU verification and validation at the majority of the Commercial Vehicle OEMs and Tier1 suppliers. HIL Testing is used to shorten development and testing time for both engine and machine control systems. In order to use this process, many of these companies have to develop and maintain expertise in the area of Model-based development (MBD). This paper introduces an approach which allows for the effective use of HIL systems without having to directly work in a MBD environment. Many HIL tests can be done with stimulus and response analysis of the ECUs, given core knowledge of the expected behavior of its control software and I/O subsystems. For hardware interface and diagnostics validation, this open-loop testing of the controller may suffice. It is important to provide the tester with capabilities to easily modify these stimuli and evaluate the responses.
2011-09-13
Journal Article
2011-01-2255
Matthew Busdiecker, Benjamin Saltsman, Douglas Hughes
Architecting and integrating commercial hybrid electric vehicles (HEV) is a long and labor intensive process which is unique every time. The challenge intensifies when one attempts to create an HEV capable of engine-off operation. In this case, electrical power needs to be supplied to devices which are normally powered by the engine accessory belt. These devices are referred to as e-accessories. To address the issue of time to market and reduce vehicle integration burden, a plug-and-play architecture for connecting e-accessories has been developed. The Flexible High Voltage DC System is analogous to a USB hub on a PC and serves to provide power, control and communication to e-accessories such as electrified power steering, electrified brakes and electrified HVAC.
2011-09-13
Journal Article
2011-01-2242
Amit J Bora, Robert White, Dalsang Chaudhari
Gear rattle noise is a common issue in manual gear transmissions and is often difficult to resolve. This paper discusses a methodology involving development of a simulation model for noise prediction and subsequent design of experiments (DOE) analysis to select optimal design parameters to reduce rattle noise. A one-dimensional torsional vibration simulation model for a tractor driveline was developed and was correlated with experimental measurements. This correlated model was used to calculate the torque variation between the gear pairs based on engine excitations. The standard deviation of this mesh torque was used as a metric and was correlated to noise ratings assigned by experts during experimental evaluation. Using this metric as the response variable, a DOE was conducted to determine the contributing factors and their influence on the rattle noise. Optimal design parameters were selected to achieve target value on the rattle metric.
2011-09-13
Technical Paper
2011-01-2241
Shuming Chen, Dengfeng Wang, Jiqiang Song, Gangping Tan, Bingwu Lu
The basic theory of statistical energy analysis (SEA) is introduced, a commercial heavy duty truck cab is divided into 35 subsystems applying SEA method, and a three dimensional SEA model of the commercial heavy duty truck cab is created. Three basic parameters including modal density, damping loss factor and coupling loss factor are calculated with analytical and experimental methods. The modal density of the regular wall plate of the cab is calculated with traditional formula. The damping loss factors of the regular and complicated plates are obtained using analytical method and steady energy stream method. Meanwhile, the coupling loss factors of structure-structure, structure-sound cavity, and cavity-cavity are also calculated. Four kinds of excitations are in the SEA model, including sound radiation excitation of engine, engine mount vibration excitation, road excitation and wind excitation.
2011-09-13
Technical Paper
2011-01-2235
Rohit Kunal
This paper presents a simulation of the stiffness of the shift fork of a manual transmission using contact pattern analysis and optistrut. All the subsystem (i.e. synchronizer and the shift system component) are constrained to optimize the shift fork stiffness. A-5-speed manual transmission is used as an example to illustrate the simulation, co-relation and validation of the optimization of the gear shift fork stiffness. The shift system was modeled in the software to collate the synchronization force, shift system gap etc with the constraint on the shift fork. It is constrained by the synchronizer sleeve and the fork mounting on the gear shift rail. The synchronizer force is then applied on the gear shift fork pads which are translated to the synchronizer sleeve. It has a number of pads which come into contact at different occasion of the synchronization because of the varying stiffness of the fork.
2009-06-15
Journal Article
2009-01-1904
Patrick Kirchen, Peter Obrecht, Konstantinos Boulouchos
Measurements of the soot emissions and engine operating parameters from a diesel engine during transient operation were used to investigate the influence of transient operation on the soot emissions, as well as to validate a realtime mean value soot model (MVSM, [1]) for transient operation. To maximize the temporal resolution of the soot emission and engine parameter measurements (in particular EGR), fast instruments were used and their dynamic responses characterized and corrected. During tip-in transients, an increase in the soot emissions was observed due to a short term oxygen deficit compared to steady-state operation. No significant difference was seen between steady-state and transient operation for acceleration transients. When the MVSM was provided with inputs of sufficient temporal resolution, it was capable of reproducing the qualitative and, in part, quantitative soot emission trends.
2009-06-15
Technical Paper
2009-01-1898
Tao Bo, Fabian Mauss, Linda M. Beck
This paper explains the principle and advantages of the Ignition Progress Variable Library (IPV-Library) approach and its use in predicting engine related premixed, non-premixed and compression ignited combustion events. The implementation of IPV-Library model in the engine-focused CFD code VECTIS is described. To demonstrate the application of the model in predicting various types of combustion, computational results from a 2-stroke HCCI engine, a premixed spark ignition engine and an HSDI diesel engine are presented, together with some comparisons with engine test data.
2009-06-15
Technical Paper
2009-01-1897
Hiroshi Kawanabe, Ryo Yamamoto, Takuji Ishiyama
Diesel combustion model for CFD simulation is established taking account of an auto-ignition process of non-homogeneous mixture. Authors revealed in their previous paper that the non-homogeneity of fuel-air mixture affected more on auto-ignition process such as its ignition delay or combustion duration than the turbulent mixing rate. Based on these results, novel diesel combustion model is proposed in this study. The transport calculation for local variation of fuel-air PDF is introduced and the chemical reaction rate is provided by the local non-homogeneity. Furthermore, this model is applied the RANS based CFD simulation of the spray combustion in a Diesel engine condition. The results show that the combustion process is well described for several engine operations.
2009-06-15
Technical Paper
2009-01-1882
Anup M. Kulkarni, Karla C. Stricker, Angeline Blum, Gregory M. Shaver
Premixed charge compression ignition (PCCI), an advanced mode combustion strategy, promises to simultaneously deliver the fuel efficiency of diesel combustion and the ultra-low NOx emissions that usually require advanced exhaust aftertreatment. A flexible, computationally efficient, whole engine simulation model for a 2007 6.7-liter diesel engine with exhaust gas recirculation (EGR), variable-geometry turbo-charging (VGT), and common rail fuel injection was validated after extensive experimentation. This model was used to develop strategies for highly fuel-efficient, ultra-low NOx emission PCCI. The primary aim of this modeling investigation is to determine the PCCI control authority present on a modern diesel engine outfitted with both conventional actuators (multi-pulse fuel injectors, an EGR valve, and VGT) and flexible intake valve closure modulation (IVCM) which dictates the effective compression ratio (ECR).
2009-06-15
Technical Paper
2009-01-1880
Mikael Lindström, Hans-Erik Ångström
The fuel injection process plays an important role in the combustion and emission formation processes of the DI diesel engine. One important fuel spray characteristic is the spray impulse. The most commonly used method to measure fuel spray impulse is the impingement method where the fuel spray impinges perpendicularly on the surface of a force transducer. This work deals with the theoretical background of such measurements as well as with developing and testing some different impulse measurement setups. The measured impulse is compared to measurements of the instantaneous mass flow and theoretical flow calculations. When measuring the impulse by impingement on the transducer membrane a fuel temperature related measurement error was encountered. This problem was solved by gluing a strike plate to the transducer membrane. The plate shielded the membrane from direct contact with the fuel.
2009-06-15
Journal Article
2009-01-1881
A. A. Boretti, H. C. Watson
Direct Injection (DI) is believed to be one of the key strategies for maximizing the thermal efficiency of Spark Ignition (SI) engines and meet the ever-tightening emissions regulations. This paper explores the use of Liquefied Petroleum Gas (LPG) liquid phase fuel in a 1.5 liter SI four cylinder gasoline engine with double over head camshafts, four valves per cylinder, and centrally located DI injector. The DI injector is a high pressure, fast actuating injector enabling precise multiple injections of the finely atomized fuel sprays. With DI technology, the injection timing can be set to avoid fuel bypassing the engine during valve overlap into the exhaust system prior to combustion. The fuel vaporization associated with DI reduces combustion chamber and charge temperatures, thereby reducing the tendency for knocking. Fuel atomization quality supports an efficient combustion process.
2009-06-15
Technical Paper
2009-01-1871
Massimo Manni, Arcangelo Pedicillo
A test procedure was set up in our laboratories to evaluate the propensity of fuels and lubricating oils towards the soot accumulation in Diesel Particulate Filters. The experimental work was carried out with the use of a passenger car diesel engine, retrofitted with an aftertreatment system composed by an oxidation catalyst and a DPF. The soot propensity was evaluated by means of repeated measurements of differential exhaust backpressure gradient, during a running period at mid load and speed. The specific fuel consumption gradient was also measured to find a correlation between both the variables. After each soot loading period, a burning off period at full load was operated for the purpose of filter regeneration. A two-phase experiment was undertaken to assess repeatability and discrimination capability of the test procedure. During the first experimental phase, repeated tests were conducted on a fuel matrix containing some surrogate fuels.
2009-06-15
Journal Article
2009-01-1936
Zheng Xu, Jianwen Yi, Eric W. Curtis, Steven Wooldridge
This paper describes a CFD modeling based approach to address design challenges in GDI (gasoline direct injection) engine combustion system development. A Ford in-house developed CFD code MESIM (Multi-dimensional Engine Simulation) was applied to the study. Gasoline fuel is multi-component in nature and behaves very differently from the single component fuel representation under various operating conditions. A multi-component fuel model has been developed and is incorporated in MESIM code. To apply the model in engine simulations, a multi-component fuel recipe that represents the vaporization characteristics of gasoline is also developed using a numerical model that simulates the ASTM D86 fuel distillation experimental procedure. The effect of the multi-component model on the fuel air mixture preparations under different engine conditions is investigated. The modeling approach is applied to guide the GDI engine piston designs.
2009-06-15
Journal Article
2009-01-1937
Yusuke Imamori, Kenji Hiraoka, Shinsuke Murakami, Hiroyuki Endo, Christopher J. Rutland, Rolf D. Reitz
Two different types of mesh used for diesel combustion with the KIVA-4 code are compared. One is a well established conventional KIVA-3 type polar mesh. The other is a non-polar mesh with uniform size throughout the piston bowl so as to reduce the number of cells and to improve the quality of the cell shapes around the cylinder axis which can contain many fuel droplets that affect prediction accuracy and the computational time. This mesh is specialized for the KIVA-4 code which employs an unstructured mesh. To prevent dramatic changes in spray penetration caused by the difference in cell size between the two types of mesh, a recently developed spray model which reduces mesh dependency of the droplet behavior has been implemented. For the ignition and combustion models, the Shell model and characteristic time combustion (CTC) model are employed.
2009-06-15
Journal Article
2009-01-1939
Mehdi Abarham, John Hoard, Dennis N. Assanis, Dan Styles, Eric W. Curtis, Nitia Ramesh, C. Scott Sluder, John M. E. Storey
EGR coolers are effective to reduce NOx emissions from diesel engines due to lower intake charge temperature. EGR cooler fouling reduces heat transfer capacity of the cooler significantly and increases pressure drop across the cooler. Engine coolant provided at 40–90 C is used to cool EGR coolers. The presence of a cold surface in the cooler causes particulate soot deposition and hydrocarbon condensation. The experimental data also indicates that the fouling is mainly caused by soot and hydrocarbons. In this study, a 1-D model is extended to simulate particulate soot and hydrocarbon deposition on a concentric tube EGR cooler with a constant wall temperature. The soot deposition caused by thermophoresis phenomena is taken into account the model. Condensation of a wide range of hydrocarbon molecules are also modeled but the results show condensation of only heavy molecules at coolant temperature.
2009-06-15
Journal Article
2009-01-1944
Michael Boye, Marcus Döring, Frank Van der Staay, Jorge Raposo, Chava Jucker, Miguel Morales, Sjoerd Hermens
One reliable way to measure the research activity in the field of engine technology is through the number of patent applications that are submitted to different patent offices in the world. This paper offers a thorough statistical analysis of the innovation trends related to downsizing in Europe, USA, Japan, China and Korea in the field of internal combustion engines during the last 10 years, as seen by the European Patent Office. It demonstrates which technical fields (e.g. super- and turbocharging, direct fuel injection systems, hybrid technology, variable valve actuation, exhaust gas recirculation, etc.) are the most active, who are the most important players and which country attracts the highest number of applications. Subfields of certain technical fields are also analyzed. The technical fields discussed are chosen according to the International Patent Classification (IPC) scheme.
2009-06-15
Technical Paper
2009-01-1943
F. Brusiani, G. M. Bianchi, M. Costa, R. Squarcini, M. Gasperini
This paper deals with a CFD three-dimensional multiphase simulation of rotary vane pump. The paper presents a suitable methodology for the investigation of the cavitation effects and/or incondensable gases. All the 3D simulations were performed by using Fluent v12 (Beta version). A moving mesh methodology was defined to reproduce the change-in-time shape of the internal pump volumes. In particular, the pump analysis was focused on the generation, and evolution of the cavitation phenomena inside the machine to identify the locations where this phenomena could occur. Moreover, the influence of incondensable gas dissolved inside the operator fluid on both pump performance and cavitation evolution was evaluated. Significant results were obtained about the analysis of incondensable gas influence on the cavitation evolution showing that, today, CFD analysis can provide detailed information on such harmful phenomena which can not be achieved by experiments.
2009-06-15
Technical Paper
2009-01-1917
Eric Doran, Heinz Pitsch, David J. Cook
A general model framework for investigating various injection strategies in compression ignition engines with both mixture and thermal inhomogeneities is presented using an extended representative interactive flamelet model. The equations describing evolution of chemistry are written for a scalar phase space of either one or two dimensions and an approach for modeling multiple injections is given. The combustion model is solved interactively with the turbulent flow field by coupling with a Reynolds-Averaged Navier-Stokes (RANS) solver. The model is applied in the simulation of a split-injection diesel engine and results are compared to experimental data obtained from a single cylinder research engine.
2009-06-15
Technical Paper
2009-01-1918
M. Cagri Cevik, Stefan Pischinger, Martin Rebbert, Franz Maassen
This paper introduces different modeling approaches of crankshafts, compares the refinement levels and discusses the difference between the results of the crankshaft durability calculation methodologies. A V6 crankshaft is considered for the comparison of the refinement levels depending on the deviation between the signals such as main bearing forces and deflection angle. Although a good correlation is observed between the results in low speed range, the deviation is evident through the mid to high speed ranges. The deviation amplitude differs depending on the signal being observed and model being used. An inline 4 crankshaft is considered for the comparison of the durability results. The analysis results show that the durability potential is underestimated with a classical crankshaft calculation approach which leads to a limitation of maximum speed of 5500 rpm.
2009-06-15
Technical Paper
2009-01-1924
S. Zanforlin, R. Gentili
A low-pressure hydrogen direct-injection solution is presented that allows some typical benefits of direct injection, such as high specific power and backfire prevention, plus low residual storage pressure, that improves vehicle range and is a typical advantage of external mixture formation. Since the injection must end early enough to allow good charge homogeneity and, in any case, before in-cylinder pressure rise constraints hydrogen admission, especially at heavy loads hydrogen flow to the cylinder is higher than present electro-injectors allow. The injection is realised in two steps: hydrogen flow rate is simply controlled by a conventional CNG electro-injector that feeds a small intermediate chamber. From this chamber hydrogen next enters the cylinder in a short crank angle period by means of a mechanically-actuated valve that opens at the intake valve closure to avoid backfire.
2009-06-15
Journal Article
2009-01-1909
S. Liebsch, O. Dingel, J. Maass, M. Günther, M. Kratzsch, S. Zwahr
The startability of SI engines, especially of DISI engines, is the greatest challenge when using ethanol blended fuels. The development of a suitable injection strategy is therefore the main engineering target when developing an ethanol engine with direct injection. In order to limit the test efforts of such a program, a vaporization model has been created that provides the quantity of vaporized fuel depending on pressure and on start and end, respectively number and split relation of injections. This model takes account of the most relevant fuel properties such as density, surface tension and viscosity. It also considers the interaction of the spray with cylinder liner, cylinder head and piston. A comparison with test results shows the current status and the need for action of this simulation model.
2009-06-15
Technical Paper
2009-01-1911
Wanhua Su, Yingying Lu, Wenbin Yu, Changqing Wang, Yiqiang Pei, Yongliang Sun, Yunqiang Li, Zhongfu Yu, Jinfeng Wang
A concept of high density-low temperature combustion (HD-LTC) is put forward in this paper, showing potential of its high thermal efficiency and very low engine-out emissions by engine experimental and CFD modeling study. A single cylinder test engine has been built-up equipped with mechanisms of variable boost pressure and intake valve closing timing (IVCT). By delaying IVCT and raising boost pressure to certain values according to engine loads, the in-cylinder charge density is regulated much higher than in conventional engines. It is found that the high charge density can play the role of rising of heat capacity as exhaust gas recirculation (EGR) does. Thereby low temperature combustion is realized with less EGR (about 18~19% oxygen concentration) to achieve very low NOx and soot emissions, which is extremely important at high and full loads.
2009-06-15
Technical Paper
2009-01-1915
M. Costa, B. Iorio, U. Sorge, S. Alfuso
Results of an experimental campaign conducted on a multi-hole gasoline injector are used to assess a numerical model for the spray dynamics suitable to be employed for the prediction of a GDI engine pressure cycle. The considered injector generates a spray with a hollow-ellipsoid footprint structure on a plane perpendicular to the spray axis. Spray penetration lengths and cone angles are measured at different injection pressures and total injected masses in an optically accessible vessel containing nitrogen at controlled conditions of temperature and pressure. Injected mass flow rate is measured on a Bosch tube. The numerical simulation is performed within the AVL Fire™ code environment. As a first step, the gasoline is considered as entering a constant volume environment containing nitrogen, in order to reproduce the effected experiments. Measured injection flow rates and cone angles are used as input variables for the model.
2009-06-15
Journal Article
2009-01-1916
Claudia O. Iyer, Jianwen Yi
A systematic methodology has been employed to develop the Duratec 3.5L EcoBoost combustion system, with focus on the optimization of the combustion system including injector spray pattern, intake port design, piston geometry, cylinder head geometry. The development methodology was led by CFD (Computational Fluid Dynamics) modeling together with a testing program that uses optical, single-cylinder, and multi-cylinder engines. The current study shows the effect of several spray patterns on air-fuel mixing, in-cylinder flow development, surface wetting, and turbulence intensity. A few sets of injector spray patterns are studied; some that have a wide total cone angle, some that have a narrow cone angle and a couple of optimized injector spray patterns. The effect of the spray pattern at part load, full load and cold start operation was investigated and the methodology for choosing an optimized injector is presented.
2009-06-15
Journal Article
2009-01-1978
Shu Gequn, Li Min, Wei Haiqiao
The simulation of main bearing load plays an important role in engine multi-body dynamics simulation, seemingly influencing the simulation of strength, vibration and acoustics. It is necessary to conduct engine bench test to validate the result of simulation. More attention has been paid to the flexibility of engine blocks and crankshafts, but not on the installing conditions of engine test bench, such as the stiffness of mounts, the presence of the connecting flange and the elasticity of shaft coupling, which are easy to ignore. The work presented here focuses on the influence of bench installation conditions on the multi-body dynamics simulation of an engine. A flexible multi-body dynamics model of a 4100QB diesel engine is built by employing the modal synthesis technique in the software ADAMS. By comparing the simulation results of different models, the effects of the connecting flange, the stiffness of mounts and the elasticity of shaft coupling are discussed.
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