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Auswahl der wissenschaftlichen Literatur zum Thema „Multi chamber cylinder“
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Zeitschriftenartikel zum Thema "Multi chamber cylinder"
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Ho Cho, Seung, Olli Niemi-Pynttäri und Matti Linjama. „Friction characteristics of a multi-chamber cylinder for digital hydraulics“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, Nr. 5 (02.03.2015): 685–98. http://dx.doi.org/10.1177/0954406215575414.
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This paper deals with the issue of defining friction characteristics of a multi-chamber cylinder for digital hydraulics. Using a multi-chamber cylinder under a set of supply pressures, friction characteristics are experimentally investigated for a range of velocity according to load conditions. A binary digit-based pressure e.g., high pressure or low pressure has been applied to each chamber. The friction force is measured based on the equation of motion using measured values of the pressures in the chambers of the multi-chamber cylinder and the position of the piston. As a mechanism to load the multi-chamber cylinder, a 1-Degree of Freedom (DOF) boom mockup mimicking a medium-sized mobile machine boom has been constructed. Then it has been utilized to test the motion of the cylinder under different mass–load conditions. It is shown that the cylinder states do not dominantly affect the friction force of a multi-chamber cylinder, comparing the effect of other parameter such as mass load and velocity, which is expected to be useful for the secondary control of digital hydraulic systems.
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Tolou, Sedigheh, und Harold Schock. „Experiments and modeling of a dual-mode, turbulent jet ignition engine“. International Journal of Engine Research 21, Nr. 6 (30.09.2019): 966–86. http://dx.doi.org/10.1177/1468087419875880.
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The dual-mode, turbulent jet ignition system is a promising combustion technology to achieve high diesel-like thermal efficiency at medium to high loads and potentially exceed diesel efficiency at low-load operating conditions. The dual-mode, turbulent jet ignition systems to date proved a high level of improvement in thermal efficiency compared to conventional internal combustion engines. However, some questions were still unanswered. The most frequent question regarded power requirements for delivering air to the pre-chamber of a dual-mode, turbulent jet ignition system. In addition, there was no study available to predict the expected efficiency of a dual-mode, turbulent jet ignition engine in a multi-cylinder configuration. This study, for the first time, predicts the ancillary work requirement to operate the dual-mode, turbulent jet ignition system. It also presents a novel, reduced order, and physics-based model of the dual-mode, turbulent jet ignition engine with a pre-chamber valve assembly. The developed model was calibrated based on experimental data from the Prototype II dual-mode, turbulent jet ignition engine. The simulation results were in good agreement with the experimental data. The validity of the model was observed based on the standard metric of the coefficient of determination as well as comparison plots for in-cylinder pressures. Numerical predictions were compared to experiments for three metrics of main chamber combustion: gross indicated mean effective pressure, main chamber peak pressure, and main chamber phasing for the peak pressure. Predictions were within 5% of experimental data, with one exception of 6%. In addition, the absolute root mean square errors of in-cylinder pressures for both pre- and main-combustion chambers were below 0.35. The calibrated model was further studied to introduce a predictive and generalized model for dual-mode, turbulent jet ignition engines. Such a model can project engine behavior in a multi-cylinder configuration over the entire engine fuel map.
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Xing, Hui, Lei Guo und Ji Wu. „Multi-Field Coupling Modeling and Analysis for Cylinder Liner of Slow Speed Two Stroke Marine Diesel Engine“. Advanced Materials Research 1070-1072 (Dezember 2014): 1856–60. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1856.
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To predict accurately the stress and deformation of combustion chamber components of large slow speed two stroke marine diesel engines, based on AVL Fire and ANSYS Workbench software, multi-field coupling modeling and analysis technology was employed to carry out the strength analysis for combustion chamber components of crosshead type marine diesel engine. The boundary conditions, i.e., the temperature field distribution, the mean temperature and the mean heat transfer coefficient are obtained firstly. Then the strength analysis for cylinder liner of crosshead type marine diesel engine under the thermal loads, mechanical loads and thermal mechanical coupled loads was conducted. The results show that the strength meets the design requirement and the stress concentration and the deformation of the cylinder liner were mainly dependent on the thermal load.
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Schneider, Bruno, Christian Schürch, Konstantinos Boulouchos, Stefan Herzig, Marc Hangartner, David Humair, Silas Wüthrich, Christoph Gossweiler und Kai Herrmann. „The Flex-OeCoS—a Novel Optically Accessible Test Rig for the Investigation of Advanced Combustion Processes under Engine-Like Conditions“. Energies 13, Nr. 7 (08.04.2020): 1794. http://dx.doi.org/10.3390/en13071794.
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A new test rig has been designed, built and commissioned, and is now jointly pursued to facilitate experimental investigations into advanced combustion processes (i.e., dual fuel, multi-mode) under turbulent conditions at high, engine-like temperature and pressure levels. Based on a standard diesel engine block, it offers much improved optical access to the in-cylinder processes due to its separated and rotated arrangement of the compression volume and combustion chamber, respectively. A fully variable pneumatic valve train and the appropriate preconditioning of the intake air allows it to represent a wide range of engine-like in-cylinder conditions regarding pressures, temperatures and turbulence levels. The modular design of the test rig facilitates easy optimizations of the combustion chamber/cylinder head design regarding different experimental requirements. The name of the new test rig, Flex-OeCoS, denotes its Flexibility regarding Optical engine Combustion diagnostics and/or the development of corresponding Sensing devices and applications. Measurements regarding in-cylinder gas pressures, temperatures and the flow field under typical operating conditions are presented to complete the description and assessment of the new test rig.
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Dong, Yi, Jianmin Liu, Yanbin Liu, Huaying LI, Shaoliang Zhang, Xuesong Hu und Xiaoming Zhang. „Structure optimization of gasket based on orthogonal experiment and NSGA-II“. Science Progress 104, Nr. 2 (April 2021): 003685042110113. http://dx.doi.org/10.1177/00368504211011347.
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With the aim of enhancing both reliability and fatigue life of gasket, this study combines finite element analysis, orthogonal experimental design, dynamically-guided multi-objective optimization, and the non-dominated sorting genetic algorithm with elitist strategy to optimize the geometric parameters of the cylinder gasket. The finite element method was used to analyze the temperature field, thermal-mechanical coupling stress field, and deformation of cylinder gasket. The calculation results were experimentally validated by measured temperature data, and comparison results show that the maximum error between calculated value and experiment value is 7.1%, which is acceptable in engineering problems. Based on above results and orthogonal experiment design method, the effects of five factors, including diameter of combustion chamber circle, diameter of coolant flow hole, length of the insulation zone between third and fourth cylinders, thickness of gasket, and bolt preload, on three indexes: temperature, stress, and deformation of gasket, were examined in depth. Through the variance analysis of the results, three important factors were identified to proceed later calculation. The dynamically guided multi-objective optimization strategy and the non-dominated sorting genetic algorithm were effectively used and combined to determine the optimal geometric parameters of cylinder gasket. Furthermore, calculation results suggest that temperature, stress, and deformation of the optimized cylinder gasket have been improved by 27.88 K, 16.84 MPa, and 0.0542 mm, respectively when compared with the origin object, which shows the excellent performance of gasket optimization and effectiveness of the proposed optimization strategy.
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Yuan, Ye, Guo Xiu Li, Yu Song Yu, Peng Zhao und Hong Meng Li. „Multi-Dimensional Simulation on the Matching of Combustion Chamber and Injection Pressure for a Heavy-Duty Diesel Engine“. Advanced Materials Research 516-517 (Mai 2012): 623–27. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.623.
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Multi-dimensional simulation was applied for the investigation of the combustion system of a heavy-duty diesel engine. Firstly, the matching of combustion chamber and injection pressure has been determined by simulation. Then through intermediate characteristic parameters which could quantitatively describe the properties of the mixing and combustion, the influence of the matching of chamber caliber ratios and injection pressure on each sub-process in compression and power stroke was analyzed comprehensively. The results showed that, for the model studied in this article, increasing the combustion chamber caliber ratio and injection pressure could help expanding the distribution range of the mixture in cylinder, making the mixture more uniform, increasing the proportion of the dilute mixture, thus effectively improved the power performance.
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Ghodke, Pundlik, und Jiwak Suryawanshi. „Investigation of diesel engine for low exhaust emissions with different combustion chambers“. Thermal Science 19, Nr. 6 (2015): 2013–24. http://dx.doi.org/10.2298/tsci140904176g.
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Upcoming stringent Euro-6 emission regulations for passenger vehicle better fuel economy, low cost are the key challenges for engine development. In this paper, 2.2L, multi cylinder diesel engine have been tested for four different piston bowls designed for compression ratio of CR 15.5 to improve in cylinder performance and reduce emissions. These combustion chambers were verified in CFD at two full load points. 14 mode points have been derived using vehicle model run in AVL CRUISE software as per NEDC cycle based on time weightage factor. Base engine with compression ratio CR16.5 for full load performance and 14-mode points on Engine test bench was taken as reference for comparison. The bowl with flat face on bottom corner has shown reduction 25% and 12 % NOx emissions at 1500 and 3750 rpm full load points at same level of Soot emissions. Three piston bowls were tested for full load performance and 14 mode points on engine test bench and combustion chamber ?C? has shown improvement in thermal efficiency by 0.8%. Combinations of cooled EGR and combustion chamber ?C? with geometrical changes in engine have reduced exhaust NOx, soot and CO emissions by 22%, 9 % and 64 % as compared to base engine at 14 mode points on engine test bench.
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Chen, S., T. L. Chan, C. W. Leung, M. A. Liu, K. Y. Pan und L. B. Zhou. „Multidimensional numerical simulation of heat radiation in direct injection diesel engines“. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 214, Nr. 4 (01.04.2000): 453–66. http://dx.doi.org/10.1243/0954407001527754.
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A multidimensional theoretical model of radiation heat transfer in the cylinder of a direct injection (DI) diesel engine has been developed, which includes submodels of heat release, geometrical description, radiation temperature, soot formation and oxidation, the absorption coefficient and the Monte Carlo method for total exchange areas. In this code, the cylinder is divided into 10 surface zones and four gas zones. The Monte Carlo method integrated with a smoothing technique considering reciprocity and conservation is used to calculate the radiation total exchange areas directly for both the absorbing—emitting media and the complex structure of the cylinder. Using the multi—dimensional approach, the variation in radiant heat transfer with crank angle can be obtained across the whole combustion chamber. The computed results are analysed and discussed in the present study, and they are found to be in agreement with the experimental results.
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Chiou, J.-S., M.-S. Chiang und C.-K. Chen. „Numerical Simulation Method Applied to the Multi-Expansion Exhaust System of a Two-Stroke Engine“. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 208, Nr. 4 (Oktober 1994): 281–88. http://dx.doi.org/10.1243/pime_proc_1994_208_195_02.
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A numerical method is presented to simulate the pressure wave in the multi-expansion exhaust system of a two-stroke engine. In the simulated processes, the inlet pipe, scavenge pipe and exhaust pipe of the two-stroke engine are simplifed by the pipe model, while the engine cylinder, crankcase and the expansion chamber are treated as the vessel model. The cubic-interpolated pseudo-particle (CIP) method combined with the method of characteristics (MOC) is used to solve the hyperbolic equations. The results from simulation compare reasonably well with the experimental data.
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Chen, Guo Jin, Zhong Min Liu, Ting Ting Liu, Shao Hui Su, Guang Jie Yuan und Yi Jiang Cao. „Analysis for Combustion Process in Cylinder of 5S60 Diesel Engine“. Advanced Materials Research 430-432 (Januar 2012): 1742–46. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1742.
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The optimization and matching question for the low-speed diesel engine’s combustion process determines its power, efficiency and emission. But the optimization and matching of the combustion process is related with the fuel injection rule, the intake swirl control, the valve timing adjustment, the combustion chamber structure, the operating condition parameter and so on. This paper takes the 5S60 marine low-speed diesel engine as the study object. The whole running phase oriented model based on the unified multi-domain has established, and the analysis for the diesel engine’s combustion process in cylinder has carried on. The analysis result provides the technical support for the economical, safe and reliable operation of the diesel engine. Thus the combustion process in cylinder is improved, the diesel engine’s performance is enhanced, and the pollutant discharge is reduced.
Dissertationen zum Thema "Multi chamber cylinder"
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Berglund, David, und Niklas Larsson. „Controlling a Hydraulic System using Reinforcement Learning : Implementation and validation of a DQN-agent on a hydraulic Multi-Chamber cylinder system“. Thesis, Linköpings universitet, Fluida och mekatroniska system, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-177216.
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One of the largest energy losses in an excavator is the compensation loss. In a hydraulic load sensing system where one pump supplies multiple actuators, these compensation losses are inevitable. To minimize the compensation losses the use of a multi chamber cylinder can be used, which can control the load pressure by activate its chambers in different combinations and in turn minimize the compensation losses. For this proposed architecture, the control of the multi chamber cylinder systems is not trivial. The possible states of the system, due to the number of combinations, makes conventional control, like a rule based strategy, unfeasible. Therefore, is the reinforcement learning a promising approach to find an optimal control. A hydraulic system was modeled and validated against a physical one, as a base for the reinforcement learning to learn in simulation environment. A satisfactory model was achieved, accurately modeled the static behavior of the system but lacks some dynamics. A Deep Q-Network agent was used which successfully managed to select optimal combinations for given loads when implemented in the physical test rig, even though the simulation model was not perfect.
Konferenzberichte zum Thema "Multi chamber cylinder"
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Niemi-Pynttäri, Olli, Matti Linjama, Arto Laamanen und Kalevi Huhtala. „Parallel Pump-Controlled Multi-Chamber Cylinder“. In ASME/BATH 2014 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fpmc2014-7820.
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This study focused on the use of fixed displacement pumps in parallel connection to control the velocity of a multi-chamber cylinder piston. The system’s basic principle was to combine the discrete flow supply control of parallel pumps with the discrete effective area control of a multi-chamber cylinder to produce a speed control resolution high enough for accurate velocity tracking and positioning. Some throttling was used in the return line to control the system with overrunning loads. The properties of the system were tested with a 1-DOF boom mockup mimicking a medium-sized mobile machine boom. The test system revealed a feature that caused load acceleration to drop when the effective cylinder area was reduced during movement. Additionally, some delay was observed in accelerating the piston against the load force. These two system properties along with the discrete control method resulted in mediocre speed and position tracking in the system when movement was directed against the load force. The system was able to control restricting and overrunning loads as well as a large inertia mass with a low load force. The system’s energy losses were low considering that no pressure accumulators were used, but the throttling losses in the return line and the lack of energy recuperation leave room for improvement.
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Hansen, Anders Hedegaard, und Henrik C. Pedersen. „Reducing Fatigue Loading due to Pressure Shift in Discrete Fluid Power Force Systems“. In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1506.
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Discrete Fluid Power Force Systems is one of the topologies gaining focus in the pursuit of lowering energy losses in fluid power transmission systems. The cylinder based Fluid Power Force System considered in this article is constructed with a multi-chamber cylinder, a number of constant pressure lines and a valve manifold. The valve manifold is used to control the connections between the cylinder chambers and the pressure lines and hereby the resulting force form the cylinder. The valve manifold is equipped with fast on/off valves. However, shifting between pressure lines may yield pressure oscillations in the cylinder chamber, especially for systems with long connections between the cylinder and the valve manifold. Hose pressure oscillations will induce oscillations in the produced piston force. Hence, pressure oscillations may increase the fatigue loading on systems employing a discrete fluid power force system. The current paper investigates the correlation between pressure oscillations in the cylinder chambers and valve flow in the manifold. Furthermore, the correlation between the pressure shifting time and the pressure overshoot is investigated. The study therefore focus on how to shape the valve flow in the manifold to reduce the added fatigue loads. A simple transmission line model is developed for the analysis. Two inputs are given in the Laplace domain and the time domain solution of the cylinder pressure to the given inputs are derived through inverse Laplace transformation. Based on the time domain solutions the pressure overshoot for various pressure shifting times is investigated. With the two input functions defined by the pressure shifting time, T, the main results of the current paper show the correlation between the minimum shifting time and the pressure overshoot in a given cylinder chamber with a given line connection.
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Kolks, Giacomo, und Jürgen Weber. „Symmetric Single Rod Cylinders With Variable Piston Area? A Comprehensive Approach to the Right Solution“. In BATH/ASME 2018 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fpmc2018-8810.
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In contrast to rotational hydraulic displacement units, such as pumps or motors, conventional hydraulic cylinder actuators do not allow a continuous variation of their displacement quantity: the piston area is regarded constant. In order to adapt to varying load and velocity requirements in a load cycle under torque restrictions of the driving motor, cylinder drives often implement pumps with variable displacement. In this paper, cylinders with discretely variable effective piston area by means of variable circuitry of multi-chamber cylinders are discussed. Hydraulic symmetry or constant asymmetry of the hydraulic cylinder are traits of the cylinder that are required to fit the cylinder to pump structures for closed-circuit displacement control, as given in electro-hydrostatic compact drives (ECD). A methodology to generate all possible solutions of variable area cylinders under the constraint of ECD requirements is proposed. A comprehensive description of the solution space is given, based on combinatorics and solution of equation systems. The methodology dealing with abstract cylinder areas is backed up by a general approach to describe the mechanical cylinder design space to combine multiple cylinder areas in one structural unit. Examples for design of three and four area cylinders are given and results are discussed. The paper concludes with the development of a demonstrator design to allow experimental validation in a subsequent step.
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Van Dam, Noah, und Christopher Rutland. „Understanding In-Cylinder Flow Variability Using Large-Eddy Simulations“. In ASME 2015 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/icef2015-1103.
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Multi-cycle Large-eddy simulations (LES) of motored flow in an optical engine housed at the University of Michigan have been performed. The simulated flow field is compared against particle image velocimetry (PIV) data in several cutting planes. Circular statistical methods have been sued to isolate the contributions to overall turbulent fluctuations from changes in flow direction or magnitude. High levels of turbulence, as indicated by high velocity root-mean square (RMS) values, exist in relatively large regions of the combustion chamber. But, the circular standard deviation, a measure of the variability in flow direction independent of velocity magnitude, is much more limited to specific regions or points, indicating much of the turbulence is from variable flow magnitude rather than variable flow direction. Using the circular standard deviation is also a promising method to identify critical points, such as vortex centers or stagnation points, within the flow, which may prove useful for future engine designers.
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Ludu, Andrei, Torsten Baufeld, Harald Philipp und Carolus Gru¨nig. „Open Chamber Spark Ignited Combustion System Development for High Power Density and Low Emissions“. In ASME 2003 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ices2003-0677.
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High power density and thermal efficiency combined with very low NOx exhaust emissions are main challenges in today’s gas engine development programmes. Until recently open chamber combustion systems using traditional spark ignition were considered to be limited by knock and misfire in their potential to achieve the above mentioned goals. The main task of the work reported here was to achieve a stable, knock-free combustion using a knock-prone gas fuel of 70 methane number for a specific power density of 25 kW/L at 250 mg/m3N NOx emission according to the TA Luft. The combustion system development was carried out on a single cylinder engine (SCE), thus, a special aspect of the work was to ensure transferability of the single cylinder engine combustion system development results to the targeted V12 multi-cylinder engine. Prior to engine testing, intensive simulation work was undertaken to specify the most promising engine hardware configurations. The main emphasis was on the 3D CFD analysis of the in-cylinder charge motion and its interaction with carefully chosen combustion chamber geometry variants. The ultimate scope was to generate high local turbulence levels during combustion, enabling a short combustion duration with low variation coefficients. The experimental phase included engine tests for several combustion relevant parameters and the detailed combustion analysis with respect to flame propagation and knock centre location using the optical combustion diagnosis system AVL VISIOLUTION. This paper describes the overall work procedure as well as the analytical and experimental methods and tools employed in the combustion system development programme. It also gives information on engine test results, the value and contribution of combustion visualisation, as well as on the engine performance which could be finally reached.
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Yadollahi, Bijan, und Masoud Boroomand. „A Numerical Investigation of Combustion Chamber Geometry Effects on Natural Gas Direct Injection Properties in a SI Engine With Centrally Mounted Multi-Hole Injector“. In ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81153.
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Due to the vast resources of natural gas (NG), it has emerged as an alternative fuel for SI internal combustion engines in recent years. The need to have better fuel economy and less emission especially that of greenhouse gases has resulted in development of NG fueled engines. Direct injection of natural gas into the cylinder of SI internal combustion engines has shown great potential for improvement of performance and reduction of engine emissions especially CO2 and PM. Direct injection of NG into the cylinder of SI engines is rather new thus the flow field phenomena and suitable configuration of injector and combustion chamber geometry has not been investigated completely. In this study a numerical model has been developed in AVL FIRE software to perform investigation of direct natural gas injection into the cylinder of spark ignition internal combustion engines. In this regard, two main parts have been taken into consideration aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multidimensional numerical simulation of transient injection process, mixing and flow field have been performed via different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability, the validated model has been applied to methane injection into the cylinder of a direct injection engine. Five different piston head shapes have been taken into consideration in investigations. An inwardly opening multi-hole injector has been adapted to all cases. The injector location has been set to be centrally mounted. The effects of combustion chamber geometry have been studied on mixing of air-fuel inside cylinder via quantitative and qualitative representation of results. Based on the results, suitable geometrical configuration for a NG DI engine has been discussed.
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Men, Yifan, und Guoming G. Zhu. „A Multi-Zone Reaction-Based Diesel Combustion Model for Model-Based Control“. In ASME 2017 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dscc2017-5074.
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A physics-based control-oriented combustion model is developed to accurately predict in-cylinder pressure and temperature of a diesel engine. The model is under the assumption that the combustion chamber consists of three zones: a liquid fuel zone, a reaction zone, and an unmixed zone. These zones are formulated to account for three key events in diesel combustion: fuel evaporation, chemical reaction, and fuel-air mixing, respectively. The liquid fuel zone is assumed to be of spherical shape. The evaporation of fuel is governed by Fick’s first law of diffusion. The reaction zone is modeled as a reactive system consisting of six species and two reaction steps. The burn rate is calculated based on species concentrations and reaction zone temperature. The unmixed zone contains only air and inert gas. The results of simulations are compared to the test data from a GM 6.7 L 8-cylinder Duramax diesel engine. The multi-zone model is shown to be capable of predicting in-cylinder pressure accurately with more degree of freedoms, compared to the singlezone reaction-based model.
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Kim, Joohan, Riccardo Scarcelli, Sibendu Som, Ashish Shah, Munidhar S. Biruduganti und Douglas E. Longman. „Assessment of Turbulent Combustion Models for Simulating Pre-Chamber Ignition in a Natural Gas Engine“. In ASME 2019 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/icef2019-7278.
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Abstract Lean combustion in an internal combustion engine is a promising strategy to increase thermal efficiency by leveraging a more favorable specific heat ratio of the fresh mixture and simultaneously suppressing the heat losses to the cylinder wall. However, unstable ignition events and slow flame propagation at fuel-lean condition lead to high cycle-to-cycle variability and hence limit the high-efficiency engine operating range. Pre-chamber ignition is considered an effective concept to extend the lean operating limit, by providing spatially distributed ignition with multiple turbulent flame-jets and enabling faster combustion rate compared to the conventional spark ignition approach. From a numerical modeling perspective, to date, still the science base and available simulation tools are inadequate for understanding and predicting the combustion processes in pre-chamber ignited engines. In this paper, conceptually different RANS combustion models widely adopted in the engine modeling community were used to simulate the ignition and combustion processes in a medium-duty natural gas engine with a pre-chamber spark-ignition system. A flamelet-based turbulent combustion model, i.e., G-equation, and a multi-zone well-stirred reactor model were employed for the multi-dimensional study. Simulation results were compared with experimental data in terms of in-cylinder pressure and heat release rate. Finally, the analysis of the performance of the two models is carried out to highlight the strengths and limitations of the two formulations respectively.
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Cantore, Giuseppe, Carlo Arturo De Marco, Luca Montorsi, Fabrizio Paltrinieri und Carlo Alberto Rinaldini. „Analysis of a HSDI Diesel Engine Intake System by Means of Multi-Dimensional Numerical Simulations: Influence of Non Uniform EGR Distribution“. In ASME 2006 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ices2006-1359.
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In order to comply with stringent pollutant emissions regulations a detailed analysis of the overall engine is required, assessing the mutual influence of its main operating parameters. The present study is focused on the investigation of the intake system under actual working conditions by means of 1D and 3D numerical simulations. Particularly, the effect of EGR distribution on engine performance and pollutants formation has been calculated for a production 6 cylinder HSDI Diesel engine in a EUDC operating point. Firstly a coupled 1D/3D simulation of the entire engine geometry has been carried out to estimate the EGR rate delivered to every cylinder; subsequently the in-cylinder flow field has been evaluated by simulating the intake and compression strokes. Finally the spray and combustion processes have been studied accounting for the real combustion chamber geometry and particularly the pollutants formation has been determined by using a detailed kinetic mechanism combustion model. The 1D/3D analysis highlighted a significant cylinder to cylinder EGR percentage variation affecting remarkably the pollutant emissions formation, as evaluated by the combustion process simulations. A combined use of commercial and in-house modified codes has been adopted.
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Chiatti, Giancarlo, und Ornella Chiavola. „Performance Characteristics of a Diesel Engine Fueled With Avio-Kerosene“. In ASME 2003 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ices2003-0556.
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A comparative series of experimental tests has been performed on a 4-stroke multi cylinder indirect injection diesel engine fueled with diesel oil, pure gas-turbine fuel and gas-turbine fuel with additives. The engine has been equipped aimed at monitoring both the overall performances and the variation with time of the pressure in the pre-combustion chamber. Some key parameters have been investigated at different engine speeds and loads (ignition delay, pressure rise in the pre-combustion chamber, power output, specific fuel consumption, exhaust gas temperature) and discussed results are presented.