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Viewing 1 to 30 of 29422
2014-11-11
Technical Paper
2014-32-0060
Giovanni Vichi, Luca Romani, Giovanni Ferrara, Luca Carmignani, Francesco Maiani
In the last years, the engineering in the automotive industry has been revolutionized by the continuous research in the reduction of consumption and pollutant emissions. On this topic there is the maximum attention both by the legislative bodies and by the costumers. The more and more severe limitations in pollutant and CO2 emissions imposed by international standards on the engine manufacturers and the increasing price of the fuel force the automotive research to more efficient and ecological engines. The standard approach for the definition of the engine parameters at the beginning of the design process is based on wide open throttle condition although, both in homologation cycles and in the real utilization, engines work mainly in partial load where the efficiency dramatically decreases. This aspect has recently become strongly relevant also for two-wheels vehicles especially for urban purpose. Within this context the authors developed an integrated numerical model, in MatLab Simulink ambient, in order to couple the engine simulation, performed by means of a 1D computer-aided engineering code, with the whole vehicle dynamic behaviour.
2014-11-11
Technical Paper
2014-32-0051
Akira Ishibashi, Muneaki Nakamura, Hitoshi Muramatsu
Fuel economy improvement has become the most important issue in automobile engine developments nowadays. For the purpose of improving fuel economy due to the higher thermal efficiency, the enhancement of compression ratio and the reduction of thermal loss through cooling have been conducted widely. Those efforts exerted in the ongoing developments to improve thermal efficiency increase the thermal load on pistons. Considering the reliability of the pistons and anti-knocking capacity of engines, it is necessary to make a better understanding of piston temperature distributions through accurate measurement under various engine operating conditions. Thus, direct and indirect measurement methods have been developed to estimate the actual piston temperature. The direct method, such as linkage-type is not typically available under higher engine speed due to the durability of linkages. The indirect method, such as material hardness-type can neither measure real-time piston temperature nor measure temperature of piston skirts which are thin-walled.    
2014-11-11
Technical Paper
2014-32-0054
Toshio Watanabe, Hiroki Sakamoto
It is well known that for high-speed planing craft with outboard motor, cavitation occurs around the lower unit(gear case) and propeller blades. There are several kinds of cavitation; (1)Tip vortex cavitation (2)Hub vortex cavitation (3)Sheet cavitation (4)Cloud cavitation (5)Root cavitation Among them ,Cloud cavitation and root cavitation lead to erosion damage on the surface of lower unit and propeller. To prevent from poor appearance or performance deterioration of outboard motor by erosion damage, It is important to simulate the occurrence of erosion in advance at the design stage. In this paper, we propose the new method of predicting the area that erosion occurs using CFD (computational fluid dynamics). In order to simulate cavitation phenomena, basically, we have implemented the CFD analysis using the barotropic model. But the area that cavitation occurs does not correspond to the position of erosion damage. Therefore, we focus on the bubble nucleus which is due to cavitation. First, we predict cavitation phenomena on the basis of single-bubble motion with Rayleigh plesset model.
2014-11-11
Technical Paper
2014-32-0006
Federico Brusiani, Gian Marco Bianchi, Cristian Catellani, Marco Ferrari, Paolo Verziagi, Dario Catanese
Abstract Still today, two-stroke engine layout is characterized by a wide share on the market thanks to its simpler construction that allows to reduce production and maintenance costs respecting the four-stroke engine. Two of the main application areas for the two-stroke engines are on small motorbikes and on handheld machines like chainsaws, brush cutters, and blowers. In both these application areas, two-stroke engines are generally equipped by a carburettor to provide the air/fuel mixture formation while the engine cooling is assured by forcing an air stream all around the engine head and cylinder surfaces. Focusing the attention on the two-stroke air-cooling system, it is not easy to assure its effectiveness all around the cylinder surface because the air flow easily separates from the cylinder walls producing local hot-spots on the cylinder itself. This problem can be bounded only by the optimization of the cylinder fin design placed externally to the cylinder surface. In the present paper the authors present a first analysis of the thermal-flow behaviour of a two stroke engine designed for brush-cutter machine applications.
2014-11-11
Technical Paper
2014-32-0052
Tatsuhiko Sato, Hirotaka Kurita, Akemi Ito, Hideyuki Iwasaki
The frictional force generated between an actual monolithic aluminum cylinder block and a piston / a piston-ring in a firing mode was measured with using a newly developed floating liner device for the first case in the world. The improvement of fuel consumption is the most important issue for engine manufactures from the viewpoint of energy and environment conservation. The piston-cylinder system plays quite important role for the reduction of the engine friction. For the improvement of the frictional behavior of the piston-cylinder system, it is beneficial to observe and analyze the frictional waveforms during an engine operation. In order to meet the above-mentioned demand, the renewed floating liner device was developed. In the newly developed floating liner device, the actual cylinder block itself was used as a test specimen, whereas a thin-walled cylindrical sleeve should be used as the test specimen in the conventional floating liner device. The measured single cylinder was an aluminum monolithic type made of hypereutectic Al-17Si alloy using a high pressure die casting process.
2014-11-11
Technical Paper
2014-32-0050
Tomokazu Nomura, Koichiro Matsushita, Yoshihiko Fujii, Hirofumi Fujiwara
To meet growing demands on the fuel economy, various studies have been made to improve thermal efficiency of engines. In spite of such efforts, approximately 30% of fuel energy is still dissipated to the atmosphere finally as cooling loss, through engine parts, coolant and oil. Therefore, if the heat dissipation from the engine is insufficient, the temperature of engine parts rises. An excessively higher engine temperature causes a degradation of engine performance and a deterioration of material strength. Especially in air-cooled engines, there are contradicting demands between the heat dissipation capacity and the light weighted compactness. Therefore, to realize the optimized design for a light and compact engine, a method of a precise temperature prediction is required in the early stage of the development. A number of studies have been made on the cooling performance and the temperature prediction of engines. In many of such studies, temperature of an engine cannot be directly estimated but heat transfer from the engine to the atmosphere and to the coolant are evaluated on the basis of heat transfer coefficients calculated by 3D-CFD.
2014-11-11
Technical Paper
2014-32-0047
Mohamed El Morsy, Gabriela Achtenova
Through PULSE platform for vibration analysis, which is developed as an advanced solution for vibration measurements was developed the robust diagnostic concept (RDC). The PULSE setup is designed to help in fault diagnosis of vehicle gearbox -the main part of vehicle powertrain-. Time Domain, Continuous Wavelet Transformation Technique (CWT), FFT and Order analysis measurements are used for detection of an artificial pitting defect in gear by tracking the gearbox response at accelerated speed and different load. The test stand is equipped with three dynamometers; the input dynamometer serves as internal combustion engine, the output dynamometers introduce the load on the flanges of output joint shafts. The pitting defect is manufactured on the tooth side of gear of the fifth speed on the intermediate shaft. Temperature effect on the vibration measurements has been also investigated to study its effect on the fault diagnosis. The presented concept has an important application in the field of mechanical fault diagnosis.
2014-11-11
Technical Paper
2014-32-0020
Patrick Falk, Christian Hubmann
Abstract Originally developed for the automotive market, a fully automatic real-time measurement tool AVL-DRIVE is commercially available for analyzing and scoring vehicle drive quality, also known as “Driveability”. This system from AVL uses its own transducers, calibrated to the sensitivity and response of the human body to measure the forces felt by the driver, such as acceleration, shock, surging, vibration, noise, etc. Simultaneously, the vehicle operating conditions are measured, (throttle grip angle, engine speed, gear, vehicle speed, temperature, etc.). Because the software is pre-programmed with the scores from a multitude of different vehicles in each vehicle class via neural networks and fuzzy logic formula, a quality score with reference to similar competitor vehicles is instantly given. This tool is already successfully implemented in the market for years to investigate such driveability parameters for passenger cars. Due to the fact that electronic systems more and more find their way into the 2-wheeler applications, motorcycle manufacturers are facing a lot of challenges and these are increasing from year to year.
2014-11-11
Technical Paper
2014-32-0059
Antonio Agresta, Francesca Di Puccio, Paola Forte, Gabriele Benigni
Abstract NVH simulations for an automotive component industry represent a convenient mean to compare different solutions and make decisions on design choices based on the predictions of the component vibro-acoustic behavior. This paper presents the vibro-acoustic characterization and comparison of two fuel rail assemblies (FRAs) by mean of simulations in Ansys Workbench & LMS Virtual.Lab. These simulations required a preliminary finite element (FE) modal analysis on the FRAs. To verify the reliability of the FE models, an experimental modal analysis was performed on one of the two fuel rails in free-free condition. The correlation between FE and test models highlighted some differences: a sensitivity study proved that the differences depend on the modeling of some brazed joints. The results of the following NVH simulations were checked by performing an acoustic impact test on the two FRAs in free-free condition inside an anechoic chamber. The comparison between the test and FE results proved that only a tuned FE model provides reliable results.
2014-11-11
Technical Paper
2014-32-0062
Jonathan Tenenbaum, Michael Shapiro, Leonid Tartakovsky
Abstract The paper presents an analytical two-dimensional model of two-phase turbulent jets with focus on fuel sprays in internal combustion engines. The developed model allows prediction of the fuel spray parameters including local fuel concentration and mixture velocity. The model proposed in this paper is based on the single-phase steady-state laminar axisymmetric jet flow field solution by Schlichting. This solution is amended to include transport of the discontinuous fuel phase in a stagnant air in the limit of a dilute fuel concentration. This two-phase jet flow model admits a closed form analytical solution for the fuel concentration distribution. This solution is then applied to turbulent jet flow as per the approach described by Schlichting and in other studies, and used to predict point-wise properties of fuel sprays in internal combustion engines. The results of model simulations are compared with the available experimental data. It was found that the analytical model predicts satisfactorily spray properties without additional assumptions or fitting coefficient.
2014-11-11
Technical Paper
2014-32-0128
Francisco Payri, José Javier Lopez, Benjamin Pla, Diana Graciano Bustamante
Abstract Direct injection compression ignited (CI) engines are today's most efficient engine technology, granting efficiencies exceeding 40% for their optimal operation point. In addition, a strong technological development has allowed the CI engine to overcome its traditional weak points: both its pollutant emissions and the gap in specific power regarding its competitor, i.e. the spark ignited (SI) engine, have been noticeably reduced. Particularly, the increase in specific power has led to the downsizing as an effective method to improve vehicle efficiency. Despite the reduction in total displacement, the cylinder displacement of current CI engines is still around 0.5 liters. For some applications (urban light duty vehicles, Range Extenders…) it may be interesting to reduce the engine displacement to address power targets around 20kW with high efficiencies. This paper assesses the thermo- and fluid-dynamic limitations which make challenging extending the application of automotive CI engines to the low power region: Firstly, space limitations for injection and combustion processes.
2014-11-11
Technical Paper
2014-32-0109
Denis Neher, Maurice Kettner, Fino Scholl, Markus Klaissle, Danny Schwarz, Blanca Gimenez
Abstract Electrical power and efficiency are decisive factors to minimise payoff time of cogeneration units and thus increase their profitability. In the case of (small-scale) cogeneration engines, low-NOx operation and high engine efficiency are frequently achieved through lean burn operation. Whereas higher diluted mixture enables future emission standards to be met, it reduces engine power. It further leads to poor combustion phasing, reducing engine efficiency. In this work, an engine concept that improves the trade-off between engine efficiency, NOx emissions and engine power, was investigated numerically. It combines individual measures such as lean burn operation, overexpanded cycle as well as a power- and efficiency-optimised intake system. Miller and Atkinson valve timings were examined using a detailed 1D model (AVL BOOST). Indicated specific fuel consumption (ISFC) was improved while maintaining effective compression ratio constant. However, brake specific fuel consumption (BSFC) rises due to lower IMEP.
2014-11-11
Technical Paper
2014-32-0023
Daniele Barbani, Niccolò Baldanzini, Marco Pierini
Abstract In the study of new solutions for motorcycle passive safety, FE models of full-scale crash tests play a strategic role. The most important issue in the development process of FE models is their reliability to reproduce real crash tests. To help the engineering in the validation phase, a sensitivity analysis of a FE model for motorcycle-car crash tests is carried-out. The aim of this study is to investigate the model response subjected to variations of specific input parameters. The DOE is performed generating a list of simulations (each one composed by a unique combination of 8 parameters) through Latin Hypercube Sampling. The outputs monitored are the Head Injury Criterion (HIC) and Neck Injury Criteria (Nij). The analysis of the results is performed using scatter plots and linear regression curves to identify the parameters that have major impact on the outputs and to assess the type of dependency (linear or non-linear).
2014-11-11
Technical Paper
2014-32-0042
Bernard Alsteens
Abstract Composite materials can bring significant weight saving in the design of a new component. These materials are one of the solutions offered to designers to achieve new fuel efficiency regulation. New challenge arises in term of design optimization and manufacturing. Shifting from a metal to composite paradigm requires a dedicated tool for composite design in order to take into account the specific composite behavior. Material performance varies widely over the entire part mainly due to the manufacturing process and the corresponding microstructure. Classical design tools are not able to describe accurately the local composite material behavior, leading to the introduction of safety factors and lack of confidence in the design. Accurate modelling of composites require the use of a multi-scale approach. The composite is not seen as a homogeneous material anymore but as a heterogeneous material made of several constituents. The mechanical performance of this composite depends on the performance of each constituent and on its microstructure.
2014-11-11
Technical Paper
2014-32-0018
Kenichi Morimoto, Kenichi Tanaka
Abstract There have been a number of attempts to clarify the relationship between motorcycle specifications and shimmy phenomenon. Some of such efforts are based on equations of motion. The methods used in those efforts are suitable for analyzing motions in a fundamental structure. However, when the degree of freedom is large, it is extremely difficult to deliver an equation of motion. Therefore, a practical method cannot be found generally when applying the methods employing equations of motion. We also conducted the analysis of shimmy using multi-body dynamics simulation. The yielded results were useful only for clarifying the differences in shimmy levels among motorcycles. However, they were not helpful to understand the relationships between specifications and shimmy phenomenon. In this study, we focused clarifying these relationships and we took four study steps shown below: 1 Narrowing down the motorcycle specifications affecting shimmy2 Determining physical parameters influential to shimmy3 Investigating how a change of physical parameters affects shimmy using simplified model4 Analyzing how the changes of motorcycle specifications affect the shimmy Following these steps, we clarified the relationships between motorcycle's specifications and shimmy by using only three physical parameters.
2014-10-13
Technical Paper
2014-01-2559
Christopher Bannister
Abstract When evaluating the performance of new boosting hardware, it is a challenge to isolate the heat transfer effects inherent within measured turbine and compressor efficiencies. This work documents the construction of a lumped mass turbocharger model in the MatLab Simulink environment capable of predicting turbine and compressor metal and gas outlet temperatures based on measured or simulated inlet conditions. A production turbocharger from a representative 2.2L common rail diesel engine was instrumented to enable accurate gas and wall temperature measurements to be recorded under a variety of engine operating conditions. Initially steady-state testing was undertaken across the engine speed and load range in order that empirical Reynolds-Nusselt heat transfer relationships could be derived and incorporated into the model. Steady state model predictions were validated against further experimental data. Model predictions for compressor wall temperature show very good correlation with measured data (average 0.4% error, standard deviation 1.27%) and turbine housing temperatures also demonstrate good agreement (average 2.7% error, standard deviation 3.58%).
2014-10-13
Technical Paper
2014-01-2558
Qiyou Deng, Richard Burke
Abstract Current turbocharger models are based on characteristic maps derived from experimental measurements taken under steady conditions on dedicated gas stand facility. Under these conditions heat transfer is ignored and consequently the predictive performances of the models are compromised, particularly under the part load and dynamic operating conditions that are representative of real powertrain operations. This paper proposes to apply a dynamic mathematical model that uses a polynomial structure, the Volterra Series, for the modelling of the turbocharger system. The model is calculated directly from measured performance data using an extended least squares regression. In this way, both compressor and turbine are modelled together based on data from dynamic experiments rather than steady flow data from a gas stand. The modelling approach has been applied to dynamic data taken from a physics based model, acting as a virtual test cell. Varying frequency sinusoidal signals were applied to the compressor and turbine pressure ratios and turbine inlet temperature to drive the physic model.
2014-10-13
Technical Paper
2014-01-2565
Harun Mohamed Ismail, Hoon Kiat Ng, Suyin Gan, Tommaso Lucchini
Abstract Modeling the combustion process of a diesel-biodiesel fuel spray in a 3-dimensional (3D) computational fluid dynamics (CFD) domain remains challenging and time-consuming despite the recent advancement in computing technologies. Accurate representation of the in-cylinder processes is essential for CFD studies to provide invaluable insights into these events, which are typically limited when using conventional experimental measurement techniques. This is especially true for emerging new fuels such as biodiesels since fundamental understanding of these fuels under combusting environment is still largely unknown. The reported work here is dedicated to evaluating the Adaptive Local Mesh Refinement (ALMR) approach in OpenFOAM® for improved simulation of reacting biodiesel fuel spray. An in-house model for thermo-physical and transport properties is integrated to the code, along with a chemical mechanism comprising 113 species and 399 reactions. Simulation results are compared against data from the Chalmers High-Pressure-High-Temperature Constant-Volume Combustion Chamber (HPHT-CVCC) experimental test-bed studies in terms of liquid-droplet penetration length, vapour penetration length and spray temporal distribution.
2014-10-13
Technical Paper
2014-01-2564
Andrew Smallbone, Amit Bhave, Peter Man
Abstract This paper demonstrates how the validation and verification phase of prototype development can be simplified through the application of the Model Development Suite (MoDS) software by integrating advanced statistical and numerical techniques. The authors have developed and present new numerical and software integration methods to support a) automated model parameter estimation (model calibration) with respect to experimental data and, b) automated global sensitivity analysis through using a High Dimensional Model Representation (HDMR). These methods are demonstrated at 1) a component level by performing systematic parameter estimation of various friction models for heavy-duty IC engine applications, 2) at a sub-component level by performing a parameter estimation for an engine performance model, and 3) at a system level for evaluating fuel efficiency losses (and CO2 sources) in a vehicle model over 160 ‘real-world’ and legislated drive cycles.
2014-10-13
Technical Paper
2014-01-2549
Mohd Farid Muhamad Said, Azhar Bin Abdul Aziz, Zulkanain Abdul Latiff, Amin Mahmoudzadeh Andwari, Shahril Nizam Mohamed Soid
Abstract Many efforts have been invested to improve the fuel efficiency of vehicles mainly for the local consumers. One of the main techniques to have better fuel efficiency is cylinder deactivation system. In this paper, the main research area is focus on the investigation of cylinder deactivation (CDA) technology on common engine part load conditions within common Malaysian driving condition. CDA mostly being applied on multi cylinders engines. It has the advantage in improving fuel consumption by reducing pumping losses at part load engine conditions. Here, the application of CDA on 1.6 liter four cylinders gasoline engine is studied. One-dimensional (1-D) engine modeling is performed to investigate the effect of intake and exhaust valve strategy on engine performance with CDA. The 1-D engine model is constructed starts from the air-box cleaner up to exhaust system according to the 1.6 liter actual engine geometries. The model is simulated at various engine speeds with full load condition.
2014-10-13
Technical Paper
2014-01-2548
Pawel Magryta, Miroslaw Wendeker, Adam Majczak, Michal Bialy, Ksenia Siadkowska
Abstract The paper presents the simulation of engine model that was made in AVL Boost Software. The model assumption was the indirect additive supplying hydrogen to the SI engine. The simulation test model of a spark ignition engine, have been developed in the AVL Boost software. The model is based on a real four-cylinder engine, codenamed A14XER that meets the Euro 5 emission standard. This engine is used in passenger vehicles Opel Corsa. In order to most accurate reflection of real engine, the model was developed based on data provided by the engine manufacturer. In the simulation studies two-zone combustion model Vibe (Vibe 2 zone) was used. A General Species Transportation model was also defined, which allowed to use the fuel as a blend of gasoline and hydrogen to supply the engine. Calculations were performed for a full load for different values of rotational speed of the engine crankshaft (from 1000 rpm to 6400 rpm). Simulation studies were performed for the original fuel (gasoline) and hydrogen additives 5, 10, 15 and 20%.
2014-10-13
Technical Paper
2014-01-2557
Mohamadamin Shamsderakhshan, Shahaboddin Kharazmi
The aim of this paper is to choose the convenient turbocharger for the OM355 naturally aspirated diesel engine and turn it to a turbocharged one. For this, 1D1 computer simulation code is used and simulation results are validated with experimental measurements. Finally, by selecting a proper turbocharger, engine power increases about 50% and specific fuel consumption decreases about 4%. Moreover, effects of exhaust manifold geometry and ambient condition on performance parameters of the turbocharged diesel engine are investigated.
2014-10-13
Technical Paper
2014-01-2556
Hiroshi Tashima, Daisuke Tsuru
Abstract The discrete multi-component model for residual heavy fuel oil (HFO), developed in the mid-2000s, proved to be a simple but practical approximation in reproduction of the combustion process of HFO sprays on a couple of CFD simulation codes. The model succeeded in providing qualitative explanation about the spray and flame progression of HFO inside constant-volume chambers (CVC), but its practical use is still underway because of its higher calculation costs. Two-component HFO model, which was introduced relatively recently, separates every spray droplet virtually into two smaller droplets of each component to calculate their evaporation process separately. The model showed good agreement with the observation results on the various HFO spray behaviors in some visualized CVCs (VCVCs). However, all the above examinations were done only qualitatively not quantitatively since the heat releases measured in the visualizing-oriented chambers of large internal volume were difficult to detect accurately.
2014-10-13
Technical Paper
2014-01-2555
Lyes Tarabet, Mohand Said Lounici, Khaled Loubar, Mohand Tazerout
Abstract Numerical simulation is a useful and a cost-effective tool for engine cycle prediction. In the present study, a dual Wiebe function is used to approximate the heat release rate in a DI, naturally aspirated diesel engine fuelled with eucalyptus biodiesel/diesel fuel blends and operated at various engine loads. This correlation is fitted to the experimental heat release rate at various operating conditions (fuel nature and engine load) using a least squares regression to find the unknown parameters. The main objective of this study is to propose a model to predict the Wiebe function parameters for more general operating conditions, not only those experimentally tested. For this purpose, an artificial neural network (ANN) is developed on the basis of the experimental data. Engine load and eucalyptus biodiesel/diesel fuel blend are the input layer, while the six parameters of the dual Wiebe function are the output layer. Levenberge-Marquardt (LM) learning algorithm is found to be the best learning algorithm with a minimum number of neurons in the hidden layer.
2014-10-13
Technical Paper
2014-01-2554
Fabio Bozza, Vincenzo De Bellis, Daniela Siano
Abstract Control of knock phenomenon is becoming more and more important in modern SI engine, due to the tendency to develop high boosted turbocharged engines (downsizing). To this aim, improved modeling and experimental techniques are required to precisely define the maximum allowable spark advance. On the experimental side, the knock limit is identified based on some indices derived by the analysis of the in-cylinder pressure traces or of the cylinder block vibrations. The threshold levels of the knock indices are usually defined following an heuristic approach. On the modeling side, in the 1D codes, the knock is usually described by simple correlation of the auto-ignition time of the unburned gas zone within the cylinders. In addition, the latter methodology commonly refers to ensemble-averaged pressure cycles and, for this reason, does not take into account the cycle-by-cycle variations. In this work, an experimental activity is carried out to characterize the effects of cyclic dispersion on knock phenomena for different engine speeds, at full load operations and referring to a spark advance of borderline knock.
2014-10-13
Technical Paper
2014-01-2577
Arash Hamzehloo, Pavlos Aleiferis
Abstract International obligations to reduce carbon dioxide emissions and requirements to strengthen security of fuel supply, indicate a need to diversify towards the use of cleaner and more sustainable fuels. Hydrogen has been recommended as an encouraging gaseous fuel for future road transportation since with reasonable modifications it can be burned in conventional internal combustion engines without producing carbon-based tailpipe emissions. Direct injection of hydrogen into the combustion chamber can be more preferable than port fuel injection since it offers advantages of higher volumetric efficiency and can eliminate abnormal combustion phenomena such as backfiring. The current work applied a fully implicit computational methodology along with the Reynolds-Averaged Navier-Stokes (RANS) approach to study the mixture formation and combustion in a direct-injection spark-ignition engine with hydrogen fuelling. Hydrogen was issued into the combustion chamber by a six-hole side-mounted injector.
2014-10-13
Technical Paper
2014-01-2578
Konrad Pietrykowski
Abstract The article presents the simulation results of the combustion process made based on a 3D-CFD mathematical model of the aircraft radial engine. The object of research was the 9-cylinder aircraft engine ASZ-62IR. The model comprised of the internal geometry of the cylinder and pipes in the cylinder head together with the inlet pipe. The model has been verified on the base of the pressure characteristics in the inlet pipe obtained from the experiment. In order to reproduce the same process of mixture formation as in the real engine, the model involved the process of induction, compression and combustion. The conducted research was aimed at verifying the influence of switching off one of the spark plugs on the combustion process. The simulation was done for three versions of ignition, for two spark plugs at the same time, only the front spark plug, only the rear spark plug. The research has been conducted in the conditions of maximum constant power of engine that is 686 kW. As a result of the conducted research, the reaction progress variables in the combustion chamber representing the spread of flame and rate of heat release have been obtained.
2014-10-13
Technical Paper
2014-01-2575
Michal Bialy, Miroslaw Wendeker, Pawel Magryta, Zbigniew Czyz, Rafal Sochaczewski
Abstract The article presents results of the 3D-CFD modeling of mixture creation process in the cylinder of diesel engine. The simulation was performed using the AVL Fire software. Based on the geometry of the ADCR engine, produced by Andoria-Mot Company, a 3D-CFD model of combustion chamber, channels in the engine head and CNG injector nozzle were created. This model prevented the simulation of the filling, compression and mixture creation process. Specially prepared CNG injector has been placed in the socket of the glow plug, to minimize interference with the structure of the engine. With this solution full functionality of the original fuel supply system was retained with the ability to work with one or two fuels. During studies the location of the gas injector nozzle was changed. The results of simulation are presented for three variants of CNG injector locations. Simulation studies prevented the determination of the degree of stratification and the distribution of fuel in the cylinder of the engine.
2014-10-13
Technical Paper
2014-01-2581
Mohammed Reza Kianifar, Felician Campean, David Richardson
This paper presents a calibration optimization study for a Gasoline Direct Injection engine based on a multidisciplinary design optimization (MDO) framework. The paper presents the experimental framework used for the GDI engine mapping, followed by an analysis of the calibration optimization problem. The merits of the MDO approach to calibration optimization are discussed in comparison with a conventional two-stage approach based on local trade-off optimization analysis, focused on a representative emissions drive cycle (NEDC) and limited part load engine operation. The benefits from using the MDO optimisation framework are further illustrated with a study of relative effectiveness of different camshaft timing control strategies (twin independent Versus fixed timing, exhaust only, inlet only and fixed overlap / dual equal) for the reference GDI engine based on the part load test data. The main conclusion is that the MDO structure offers an effective framework for the GDI steady state calibration optimization analysis.
2014-10-13
Technical Paper
2014-01-2579
Martin Söder, Lisa Prahl Wittberg, Bjorn Lindgren, Laszlo Fuchs
Abstract In this work, the effect of swirl to tumble ratio on homogeneity, turbulence and mixing in a generic heavy duty Diesel engine during compression, is investigated using Large-Eddy Simulations. The main conclusion is that the relative importance of dilatation (relative volume change) increases whereas the effect of tumble breakdown decreases with the swirl to tumble ratio. In detail, we show that an increase in tumble raises the peak turbulence level and shifts the peak to earlier crank angles, which in turn leads to higher dissipation. Moreover, maximum turbulence level at top dead center is obtained for a combination of swirl and tumble rather than for pure tumble. Furthermore, it is observed that the peak turbulent kinetic energy displays levels three times greater than the initial kinetic energy of the tumble motion. Thus, energy is added to the flow (turbulence) by the piston through generation of vorticity by vorticity-dilatation interaction. Also, the intermediate swirl/tumble ratios are found to introduce large non-uniformity in the flow field, leading to a non-solid body like rotation.
Viewing 1 to 30 of 29422