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2016-10-17
Technical Paper
2016-01-2158
Jian Gao, Giacomo Cuneo
In small and compact class vehicles equipped with diesel engines, the 2-valve-per-cylinder design still holds a significant share of the market, notably for European traditional diesel-oriented OEMs. Such engines are very efficient and reasonably fun-to-drive, while being complaint to the increasingly stringent emission regulations, showing the technical and commercial potential of 2-valve engine is far from exhausted. The current work describes the numerical simulation of port-valve-cylinder flow in a 1.2L 2-valve-per-cylinder diesel engine to characterize the performance of its manifold and intake ports at rated power conditions as part of the development activities for this new diesel engine architecture. First, evaluation metrics were defined and analysis procedure was established for CFD assessment of intake manifold performance in multi-cylinder engines.
2016-10-17
Technical Paper
2016-01-2160
Alexander Bech, Paul J. Shayler, Michael McGhee
The application of cylinder deactivation technology to small, three cylinder spark ignition engines has the potential to further improve the part load fuel economy of these downsized engines. Although the technology is well established and proven for larger multi-cylinder engines, this is not the case for the class of 1.0litre, three cylinder engines produced by several OEM’s for use in small cars. Deactivating one cylinder by leaving the intake and exhaust valves closed and cutting fuelling requires the other two cylinders to produce more work output to compensate. This changes the distribution of heat rejection to the engine structure. The resulting increases in temperature gradients within the engine structure, and transient response times for thermal adjustments following deactivation or reactivation are examples of the uncertainties which the work reported addresses.
2016-10-17
Technical Paper
2016-01-2161
Gangfeng Tan
Mg2Si1-xSnx thermoelectric material is eco-friendly and of high thermoelectric performance. In this research heat transfer and power generating characteristics of the automobile exhaust heat recovery system based on Mg2Si1-xSnx material were studied. Firstly, the heat transfer model for the exhaust heat recovery system was established. Then, based on primitive characteristics of Mg2Si1-xSnx material under the different Sn/Si ratio, two-phase heat transfer of coolant was adopted and the heat transfer process was analyzed. Finally, when the saturation temperature of coolant in the two-phase zone was respectively 373K and 343K, the heat transfer and power generating characteristic were analyzed for each condition.
2016-10-17
Technical Paper
2016-01-2178
Daniela Siano, Gerardo Valentino, Fabio Bozza, Arturo Iacobacci, Luca Marchitto
In this paper, a downsized twin-cylinder turbocharged spark-ignition engine is experimentally investigated at test-bench in order to verify the potential to estimate the peak pressure value and the related crank angle position based on vibrational data acquired by an accelerometer sensor. Purpose of the activity is to provide the ECU of additional information to establish a closed-loop control of the spark timing, on a cycle-by-cycle and cylinder-by-cylinder basis. In this way, an optimal combustion phasing can be more properly accomplished in each engine operating condition. Vibrational data are also employed to have information on cycle-by-cycle variations (CCVs) of the pressure peak. More sophisticated techniques for the control of the cycle dispersion are also foreseen. To this aim, engine behavior is firstly characterized in terms of average thermodynamic and performance parameters and CCVs at high-load operation.
2016-10-17
Technical Paper
2016-01-2189
Bo WANG, Tawfik Sayed Ahmed Badawy, Yanfei Li, Hongming Xu, Xinyu Zhang, Yizhou Jiang
Atomization of fuel sprays is a key factor in control of combustion quality in direct-injection engines. In this present work, effect of injection pressure and flash boiling levels of Ethanol (ETH) on near nozzle spray patterns was investigated using an ultra-high speed imaging technique. Ethanol was injected from a single-hole piezo injector into an optically accessible constant volume chamber at injection pressures of 30 MPa, 40 MPa and 50 MPa at different back pressure and temperature. High-speed imaging was performed using a long-distance microscope coupled with an ultra-high speed camera (Shimadzu HPV-2). The results revealed a clear mushroom-like structure at the start of injection at 30 MPa injection pressure and ambient condition whereas at higher injection pressure or higher flash boiling level this mushroom shaped injection tip was not observed. Micro cone angle experienced a sudden increase during the start of spray and then dropped.
2016-10-17
Technical Paper
2016-01-2192
Mohammadreza Anbari Attar, Tawfik Badawy, Hongming Xu
This paper presents a systematic study of multi-hole gasoline direct injector (GDI) coking effects on fuel injection and mixture preparation. Experimental works were carried out in a constant volume chamber and a single-cylinder optical GDI engine. Clean injectors were coked in a designed conditioning cycle. Droplet size and velocities were measured with a Particle Doppler Phase Analyser (PDPA) system. Spray angle, plumes’ penetration length and velocity were quantified using high-speed imaging. Planar Laser Induced Fluorescence (PLIF) technique was employed for investigation of in-cylinder charge stratification at vicinity of spark plug prior to ignition. Experimental data were used to assess differences between clean and the coked injectors to attain better understanding of coking phenomenon.
2016-10-17
Technical Paper
2016-01-2193
Gen Shibata, Hideyuki Ogawa, Fukei Sha, Kota Tashiro
The diesel particulate filter (DPF) has become widely used in diesel engines, and regular regeneration is necessary to remove particulate matter accumulating on the DPF. This may be achieved with fuel injected after the main combustion is complete, so-called post fuel injection, and supplied to the diesel oxidation catalyst (DOC) upstream of the DPF. This increases the exhaust gas temperature in the DOC and the DPF is regenerated with this high temperature gas flow. In most cases, the post fuel injection takes place at 30-90 CA ATDC, and the fuel may impinge on and adhere to the cylinder liner in some cases. The research group of Buddie and Pischinger have reported oil dilution with the post fuel injection by engine tests and simulations. Such adhering fuel is a cause of worsening fuel consumption.
2016-10-17
Technical Paper
2016-01-2191
Peter Deckelmann
This paper will focus on a powertrain injector application (PIA) solution for R&D and production. PIA is a product for triggering and analyzing current and newly developed injection valves (both piezo and solenoid). The article examines an important obstacle of injection testing, which is creating realistic environmental conditions for injectors. It shows, how PIA realizes this through high-end ECU simulation for current and new generations, creating different operating conditions. Berghof Testing combined control, performance and measuring technology into PIA. The compact, intelligent and economical device can be integrated into all existing injector test systems. In addition to the standard version the application offers enhancements such as intelligent injections, injector calibration, polarity detection and image processing for spray analyses. This excludes evaluations based on erroneous fundamentals of the injection behavior to make sure injection can in fact get cleaner.
2016-10-17
Technical Paper
2016-01-2196
Stefan Stojanovic, Andrew Tebbs, Stephen Samuel, John Durodola
With a push to continuously develop traditional engine technology efficiencies and meet stringent emissions requirements, there is a need to improve the precision of injection rate measurement used to characterise the performance of the fuel injectors. New challenges in precisely characterising injection rate present themselves to the Original Equipment Manufacturers (OEMs), with the additional requirements to measure multiple injection strategies, increased injection pressure and rate features. One commonly used method of measurement is the rate tube injection analyser; it measures the pressure wave caused by the injection within a column of stationary fluid. In a rate tube, one of the significant sources of signal distortion is a result of the injected fluid pressure waves reflected back from the tube termination.
2016-10-17
Technical Paper
2016-01-2197
Chengjun Du, Mats Andersson, Sven Andersson
Effects of nozzle geometry on diesel spray characteristics were studied in a spray chamber using three single-hole nozzles, one cylindrical and two conical, designated N1 (outlet diameter 140 µm, k-factor 0), N2 (outlet diameter 140 µm, k-factor 2) and N3 (outlet diameter 136 µm, k-factor 2). To characterize the hydraulic properties of the nozzles, impingement measurements were carried out under ambient conditions and injection pressures ranging from 800 to 1600 bar. Spray experiments were performed with each of these nozzles at two constant gas densities (15 and 30 kg/m3), one temperature 673 K, at which evaporation occurs. A light absorption scattering technique using visible and UV light was implemented, and the liquid and vapor phase distributions were imaged. The data show that effects of nozzle geometry on the vapor phase penetration and local spray cone angle differ with gas density and injection pressure.
2016-10-17
Technical Paper
2016-01-2194
Muhsin M. Ameen, Prithwish Kundu, Sibendu Som
In this work, a turbulent combustion model is developed for large eddy simulation (LES) using a novel flamelet tabulation technique based on the framework of the multi-flamelet representative interactive flamelet (RIF) model. The overall aim is to develop a detailed model with elaborate chemistry mechanisms, LES turbulence models and highly resolved grids leveraging the computational cost advantage of a tabulated model. A novel technique of implementing unsteady flamelet libraries without the use of progress variables is proposed. These flamelet libraries use the residence time as one of the independent variables instead of using the traditional progress variable approach. In this study, LES of n-dodecane spray flame is performed using the tabulated turbulent combustion model along with a dynamic structure subgrid model. A high-resolution mesh is employed with a cell size of 62.5 microns in the entire spray and combustion regions.
2016-10-17
Technical Paper
2016-01-2200
Tobias Knorsch, Maximilian Miller, Philipp Rogler, Wolfram Wiese
In order to satisfy future emission classes, such as the EU6c in particular, the particulate number (PN) of Direct-Injection Spark-Ignition (DISI) engines must be reduced. For these engines, different components influence the combustion process and thus also the formation of soot particles and deposits. Among other engine components, the injector nozzle influences the particulate number and deposits in both fuel spray behavior and nozzle “tip wetting”. In case of non-optimized nozzle layouts, fuel may impinge on piston and liner in an unfavorable way, which implies low-oxygen diffusive combustion by retarded vaporizing wall films. For the tip wetting, wall films are present on the actual surface of the nozzle tip, which is also caused by unadapted nozzles. For non-optimized nozzles, the latter effect can become quite dominant. This paper deals with systematic nozzle development activities towards low-deposit nozzle tips and thus decreasing PN values.
2016-10-17
Technical Paper
2016-01-2201
Meng Tang, Le Zhao, Seong-Young Lee, Jeffrey Naber
Extensive studies have addressed diesel sprays under vaporizing and combusting conditions respectively, but further insights into the mechanism by which combustion alters the global spray penetration and shape of the spray under diesel engine conditions are needed. Contradictory observations are reported in the literature regarding the combusting diesel spray penetration compared to inert conditions, and it is the objective of this study to provide further insight and analysis on the combusting spray characteristics by expanding the range of operating parameters. Parameters varied in the studies are charge gas conditions including oxygen level (0 %, 15%, 19%), charge density (22.8 & 34.8kg/m3), and charge temperature (800K, 900K & 1050K) for injection pressures of 1200, 1500, and 1800 bar with a single hole injector with a nozzle diameter of 100 μm. These represent conditions for operation of a modern fuel injection system diesel engine at high load with EGR.
2016-10-17
Technical Paper
2016-01-2198
Chikara Dodate, Sachio Mori, Masato Kawauchi, Rio Shimizu
In recent years, a lot of direct-injection gasoline engines are developed due to the high rated power, low end torque and fuel efficiency because of increased volumetric efficiency and reduced knocking. On the other hand, the measure for particular matters (PM) and the oil dilution become important. Therefore it is necessary to identify a spray behavior in cylinder with the combination of flow to design a direct injector. To identify the spray behavior, a CFD analysis has been utilized. However, before it was necessary to fit spray model constants and parameters based on measurement results including a penetration and SMD. Especially, in the case of the nozzle whose sectional area of exit is larger than that of inlet like a fan-shape spray nozzle, the fitting process is complicated, because of an inhomogeneity internal flow. In this study, new simulation method of spray is developed.
2016-10-17
Technical Paper
2016-01-2199
Alessandro Montanaro, Luigi Allocca, Maurizio Lazzaro, Giovanni Meccariello
Mixture formation is fundamental for the development of the combustion process in internal combustion engines, for the highest release of energy and lowering the formation of pollutants. Regarding the spark ignition engines, the direct injection technology is being considered as an effective mean to achieve the optimal air-to-fuel ratio distribution at each engine operating condition. That either through charge stratification around the spark plug and stoichiometric mixture under the high power requirements. The impact of a spray on the piston or on the cylinder walls causes the formation of liquid film (wall-film) and droplet secondary atomization. The wall-film may have no negligible size, especially where the mixture formation is realized under a wall guided mode. This work aims to report the effects of the fueling injection pressure and wall temperature on the macroscopic parameters of the spray impinging on the wall.
2016-10-17
Technical Paper
2016-01-2202
Naoya Ochiai, Jun Ishimoto, Akira Arioka, Nobuhiko Yamaguchi, Yuzuru Sasaki, Nobuyuki Furukawa
The advanced development and optimization of fuel atomization in port and direct injection systems for automobile engine is desired for the improvement of fuel combustion performance and thermal efficiency of the engine. Computational prediction and design of injector nozzle spray flow is an effective method for that. However, a practical simulation method of the continuous primary, secondary spray breakups and the spraying behavior have not been developed yet. In this study, we have developed the integrated computational method of the total fuel atomization process of the injector nozzle. This new computational approach is taking into account the nozzle internal flow to form the primary breakup using Volume of Fluid (VOF) method in connection with the spray flow characteristics to the engine cylinder using Discrete Droplet Model (DDM).
2016-10-17
Technical Paper
2016-01-2203
Lan Wang, Guoxiu Li, Zuoyu SUN, Jie Wang, Jie Wang, Shuangyi He
The electromagnetic valve driving mechanism is the significant equipment, which plays a vital role in the unit pump injection system; therefore, the performance of the electromagnetic valve directly influences the function of the control system. Based on the operation conditions of the unit pump injection system, a steady electromagnetic valve model was modified to study the influence factors of electromagnetic force and the best combination to get the maximum electromagnetic force. The validation model was verified by experiment. The effects of some crucial parameters upon the electromagnetic force were investigated in the present paper, (including working airspace, magnetic pole’s cross-sectional area, coil position, coil turn, the armature thickness). The result shows that the electromagnetic force of the solenoid valve enhanced with the increasing driving current and reduced with the decreasing of working condition.
2016-10-17
Technical Paper
2016-01-2228
Mithilesh Kumar Sahu, Tushar Choudhary, Sanjay Y
Global energy scenario requires thermal systems with high thermal efficiency and low capital and operating cost. The paper deals with the thermoeconomic analysis of the gas turbine cycles with possible application as marine gas turbines. A thermoeconomic analysis is a combined study of thermodynamic and economic parameters of proposed energy conversion cycle. In present paper gas turbine of suitable configuration has been analysed. Different configurations of gas turbine have been analysed using thermo-economic methodology keeping the gas turbine output fixed. The approach used for solution of this is thermoeconomic optimization by considering appropriate objective function in a form of decision variables. This objective function combines the expenditure of financial resources (economics) and thermodynamic equations.
2016-10-17
Technical Paper
2016-01-2227
Nik Muhammad Hafiz, Mohd Radzi Abu Mansor, Wan Mohd Faizal Wan Mahmood, Masahiro Shioji
Hydrogen as a fuel in internal combustion engines has been studied extensively by researchers nowadays. Among the advantages of hydrogen are it is sustainable renewable energy, and the emission from combustions is environmentally friendly compared with other conventional fuel, which complies with a stringent policy from international energy agency. Moreover, emission from hydrogen fuel will meet the new regulation set by Malaysia National Automotive Policy (NAP). In order to enhance power output and volumetric efficiency, at the same time encounter the pre-ignition and knock problems, the hydrogen fuel compression ignition internal combustion engine in the noble gas atmosphere (argon) is selected as one of a solution by some researchers. However, the obtained data for this kind of research is still at the initial stage.
2016-10-17
Technical Paper
2016-01-2230
Vincenzo De Bellis, Fabio Bozza, Daniela Siano, Gerardo Valentino
In this paper, the results of an extensive experimental analysis regarding a twin-cylinder spark-ignition turbocharged engine are employed to build up an advanced 1D model, which includes the effects of cycle-by-cycle variations (CCVs) on the combustion process. Objective of the activity is to numerically estimate the CCV impact primarily on fuel consumption and knock behavior. To this aim, the engine is experimentally characterized in terms of average performance parameters and CCVs at high and low load operation. In particular, both a spark advance and an air-to-fuel ratio () sweep are actuated. Acquired pressure signals are processed to estimate the rate of heat release and the main combustion events. Moreover, the Coefficient of Variation of IMEP (CoVIMEP) and of in-cylinder peak pressure (CoVpmax) are evaluated to quantify the cyclic dispersion and identify its dependency on peak pressure position.
2016-10-17
Technical Paper
2016-01-2229
Alessio Dulbecco, Stephane Richard, Olivier Laget, Philippe Aubret
Turbulence is a crucial topic to account for when dealing with Spark Ignition (SI) engines. In fact, it is well known that combustion in SI engines strongly depends on in-cylinder turbulence characteristics. By definition turbulence presents three-dimensional features; accordingly, three dimensional approaches are mainly used to investigate the in-cylinder flow and assist the engine design process over a large range of operating conditions. However, SI engine architectures are becoming more and more complex and the generalization of technologies such as Variable Valve Timing (VVT) and Direct Injection (DI) considerably increase the number of degrees of freedom to account for. In this context, the resources demanded by 3D CFD codes hugely increase and car manufacturers privilege system simulation approaches, commonly based on models adopting 0D / 1D formalisms.
2016-10-17
Technical Paper
2016-01-2233
Matthew C. Robinson, Nigel Clark
The free piston engine combined with a linear electric alternator has the potential to be a highly efficient converter from fossil fuel energy to electrical power. With only a single moving part (the translating rod) mechanical friction is reduced compared to conventional crankshaft technology. Instead of crankshaft linkages, the motion of the translator is driven primarily by the force balance between the engine cylinder, alternator, damping losses, and springs. Focusing primarily on mechanical springs, this paper explores the use of springs to increase engine speed and reduce cyclic variance. A numeric model has been constructed in MATLAB®/Simulink to represent the various subsystems, including the engine, alternator, and springs. Within the simulation is a controller that tries to force the engine to operate at a fixed compression ratio by affecting the alternator load.
2016-10-17
Technical Paper
2016-01-2231
Aras Mirfendreski, Andreas Schmid, Michael Grill, Michael Bargende
Longitudinal models are used to evaluate different vehicle-engine concepts with respect to driving behavior and emissions. The engine is generally map-based. An explicit calculation of both fluid dynamics inside the engine air path and cylinder combustion is not considered due to long computing times. Particularly for dynamic certification cycles (WLTC, US06 etc.), dynamic engine effects severely influence the quality of results. Hence, an evaluation of transient engine behavior with map-based engine models is restricted to a certain extent. The coupling of detailed 1D-engine models is an alternative, which rapidly increases the model computation time to approximately 300 times higher than that of real time In many technical areas, the Fourier Transformation (FT) method is applied, which makes it possible to represent superimposed oscillations by their sinusoidal harmonic oscillations of different orders.
2016-10-17
Technical Paper
2016-01-2234
Ahmed F. Khan, Alexey Burluka, Jens Neumeister, Dave OudeNijewem, Paul Freeland
A holistic modelling approach has been employed to predict combustion, cyclic variability and knock propensity of a turbocharged downsized SI engine fuelled with gasoline. A quasi-dimensional, thermodynamic combustion modelling approach has been coupled with chemical kinetics modelling of autoignition using reduced mechanisms for realistic gasoline surrogates. The quasi-dimensional approach allows a fast and appreciably accurate prediction of the effects of operating conditions on the burn-rate and makes it possible to evaluate engine performance. It has also provided an insight into the nature of the turbulent flame as the boost pressure and speed is varied. In order to assess the sensitivity of the end-gas chemical kinetics to cyclic variability, the in-cylinder turbulence and charge composition were perturbed according to a Gaussian distribution.
2016-10-17
Technical Paper
2016-01-2232
Yves Compera, Bernhard Penkert, Georg Wachtmeister
This paper presents a phenomenological and semi-empirical simulation model to predict the injection rate of a diesel solenoid valve injector based on few injection-quantity measurements and indications (EMI). The approached injection rate will be used as the input data for a subsequent model which simulates the rate of heat release (ROHR). The injection rate model encompasses algebraic relations and differential equations deviated of the equations of motion and conservation, which describe in modular sub models the characteristic processes in the injector. The process and its assumptions are explained step by step for each sub model. Additionally the injection rate predictions are presented and compared with experimental results for a selected reference solenoid valve injector.
2016-10-17
Technical Paper
2016-01-2237
Christopher Kim Blomberg, Lucas Zeugin, Sushant S. Pandurangi, Michele Bolla, Konstantinos Boulouchos, Yuri M. Wright
This study investigates n-dodecane split injections of “Spray A” from the Engine Combustion Network (ECN) using two different turbulence treatments (RANS and LES) in conjunction with a Conditional Moment Closure combustion model (CMC). The two Modeling approaches are first assessed in terms of vapor spray penetration evolutions of non-reacting split injections showing a clearly superior performance of the LES compared to RANS: while the former successfully reproduces the experimental results for both first and second injection events, the slipstream effect in the wake of the first injection jet is not accurately captured by RANS leading to an over-predicted spray tip penetration of the second pulse. In a second step, two reactive operating conditions with the same ambient density were investigated, namely one at a diesel-like condition (900K, 60bar) and one at a lower temperature (750K, 50bar).
2016-10-17
Technical Paper
2016-01-2235
Prithwish Kundu, Riccardo Scarcelli, Sibendu Som, Andrew Ickes, Yan Wang, John Kiedaisch, M Rajkumar
Heat loss through wall boundaries play a dominant role in the overall performance and efficiency of internal combustion engines. Typical engine simulations use constant temperature wall boundary conditions. These boundary conditions cannot be estimated accurately from experiments due to the complexities involved with engine combustion. As a result they introduce a large uncertainty in engine simulations and serve as a tuning parameter. Modeling the process of heat transfer through the solid walls in an unsteady engine CFD simulation can lead to the development of higher fidelity engine simulation models. These models can be used to study the impact of heat loss on engine efficiency and explore new design methodologies that can reduce heat losses. In this work a single cylinder diesel engine is modeled along with the solid piston coupled to the fluid domain.
2016-10-17
Technical Paper
2016-01-2236
Jann Koch, Guoqing XU, Yuri M. Wright, Konstantinos Boulouchos, Michele Schiliro
Three dimensional reactive CFD plays a crucial role in IC engine development tasks complementing experimental efforts by providing improved understanding of the combustion process. A widely adopted combustion model in the engine community for (partially) premixed combustion is the G-Equation where the flame front is represented by an iso-level of an arbitrary scalar G. A convective-reactive equation for this iso-surface is solved, for which the turbulent flame speed ST must be provided. In this study, the commonly used and well-established Damköhler correlation is compared to a novel, physically sound closure derived from an algebraic closure for the scalar dissipation of reaction progress as proposed by Kolla et al. [1].
2016-10-17
Technical Paper
2016-01-2280
Emilio Xuereb, Mario Farrugia
Diesel particulate filters (DPF) regeneration is required to remove accumulated particulate matter in DPF. High pressure drop across DPF triggers an active regeneration by the ECU to burn off the accumulated soot. In city driving such as in a small island as Malta, exhaust gas temperatures are not high enough for passive regenerations, and ECU active regeneration might fail due to short trips. The particulate loading quantity in DPF is beneficial information as it provides an estimate of the remaining mileage expectancy of the DPF. Many vehicles provide information on particulate filter loading quantity in the OBD data. However, since this parameter is not on the mandatory list, different manufacturers provide this loading parameter in different forms, e.g. : grams; percentage (%); remaining mileage; etc. Thus comparison of the loading quantity across different manufacturers is not straightforward.
2016-10-17
Technical Paper
2016-01-2281
Simon Dosda, David Berthout, Gilles Mauviot, Adeline Nogre
With the upcoming Euro 6c emission regulations, the performance of Diesel exhaust lines needs to be improved to meet the NOX and soot emission targets. A promising exhaust line architecture to meet these requirements is the association of a Diesel Oxidation Catalyst (DOC), a Selective Catalytic Reduction coated on a particulate filter (SCR-F) and a Selective Catalytic Reduction (SCR) catalyst. To develop this system, the car manufacturers have to face several challenges. One of the first is the design of the exhaust line volumes, which has a strong impact on the light-off temperatures of the catalysts and so on system performance. Then, urea injection has to be optimized with an adapted control system to maximize NOx reduction while keeping low tailpipe ammonia emission. Moreover, performance degradation of catalysts due to harsh exhaust conditions during vehicle life time have to be detected by OBD system.
Viewing 1 to 30 of 31327