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Axial Flow Turbine Concept for Conventional and e-Turbocharging

Brunel University-Apostolos Pesyridis
Universita di Napoli Federico II-Alessandro Cappiello, Raffaele Tuccillo, Maria Cristina Cameretti
Published 2019-09-09 by SAE International in United States
Engine downsizing has established itself as one of the most successful strategies to reduce fuel consumption and pollutant emissions in the automotive field. To this regard, a major role is played by turbocharging, which allows an increase in engine power density, so reducing engine size and weight. However, the need for turbocharging imposes some issues to be solved. In the attempt of mitigating turbo lag and poor low-end torque, many solutions have been presented in the open literature so far, such as: low inertia turbine wheels and variable geometry turbines; or even more complex concepts such as twin turbo and electrically assisted turbochargers. None of them appears as definitive, though.As a possible way of reducing turbine rotor inertia, and so the turbo lag, also the change of turbine layout has been investigated, and it revealed itself to be a viable option, leading to the use of mixed-flow turbines. Only recently, the use of axial-flow turbines, with the aim of reducing rotor inertia, has been proposed as well.The current paper documents a case study involving the…
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Integrated CFD-Experimental Methodology for the Study of a Dual Fuel Heavy Duty Diesel Engine

Brunel University London-Vinícius Pedrozo, Hua Zhao
University of Napoli Federico II-Maria Cristina Cameretti, Roberta De Robbio, Raffaele Tuccillo
  • Technical Paper
  • 2019-24-0093
Published 2019-09-09 by SAE International in United States
This paper deals with the experimental and numerical investigation of a 2.0 litre single cylinder Heavy Duty Diesel Engine fuelled by natural gas and diesel oil in Dual Fuel mode. Due to the gaseous nature of the main fuel and to the high compression ratio of the diesel engine, reduced emissions can be obtained. An experimental study has been carried out at three different load level (25%, 50% and 75% of full engine load). Basing on experimental data, the authors recreated a 45° mesh sector of the engine cylinder and performed CFD simulations for the cases at 50% and 75% load levels. Numerical simulations were carried out on the 3D code Ansys FORTE. The aim of this work is to study combustion phenomena and, in particular, the interaction between natural gas and diesel oil, respectively represented by methane and n-dodecane. A reduced kinetic scheme for methane auto-ignition was implemented while for n-dodecane two set of reactions were utilised. The first one consisting of a one-step mechanism is compared with the far more detailed second one…
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Modeling of a Spark Ignition Engine with Turbo-Generator for Energy Recovery

Istituto Motori CNR - Napoli-Luigi De Simio, Sabato Iannaccone
NETCOM Group - Napoli-Fabio Arminio
  • Technical Paper
  • 2019-24-0084
Published 2019-09-09 by SAE International in United States
Increasingly stringent regulations in the field of pollutant are forcing engine manufacturers to adopt new solutions to contain exhaust emissions, such as Hybrid Electric Vehicles (HEV) or Full Electric Vehicles (FEV).Still far from the wide diffusion of FEV limited from electrochemical storage systems together with the difficulty of creating adequate infrastructure distributed throughout the territory to recharging batteries, the HEV seems to be actually a better solution. The hybrid vehicle is already able to guarantee satisfactory autonomy and low pollution levels by combining the advantages offered by the two technologies of thermal and electric propulsion.Currently on the market there are several types of hybrid vehicles, with different degree of hybridization (electric motor power versus propulsion total power), capacity to store electricity and type of scheme constructive adopted for the integration between the thermal engine and the electric machine.A particular interest is getting the mild-hybrid (or light hybridization) and the micro-hybrid (or minimum hybridization) with 48V electrical system added to the classic 12V one.A possible solution could be the electric turbo-compounding system where a turbine coupled…
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CFD Analysis of the Combustion Process in Dual-Fuel Diesel Engine

Istituto Motori CNR-Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco
University of Napoli Federico II-Maria Cristina Cameretti, Roberta De Robbio, Raffaele Tuccillo
Published 2018-04-03 by SAE International in United States
Dual-fuel technology has the potential to offer significant improvements in the emissions of carbon dioxide from light-duty compression ignition engines. The dual-fuel (diesel/natural gas) concept represents a possible solution to reduce emissions from diesel engines by using natural gas (methane) as an alternative fuel. Methane was injected in the intake manifold while the diesel oil was injected directly into the engine.The present work describes the results of a numerical study on combustion process of a common rail diesel engine supplied with natural gas and diesel oil. In particular, the aim is to study the effect of increasing methane concentration at constant injected diesel amount on both pollutant emissions and combustion evolution.The study of dual-fuel engines that is carried out in this paper aims at the evaluation of the CFD potential, by a 3-dimensional code, to predict the main features of this technology. In fact, to better understand the phenomena that take place during the dual-fuel operation (flame propagation throughout the premixed methane-air medium activated by the early self-ignition of the diesel fuel), the fluid-dynamic calculations…
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3D CFD Analyses of Intake Duct Geometry Impact on Tumble Motion and Turbulence Production in SI Engines

FCA EMEA-Agostino Iorio, Luigi Maresca
Univ. of Napoli Federico II-Maria Cristina Cameretti, Vincenzo De Bellis, Luca Romagnuolo
Published 2017-10-08 by SAE International in United States
In recent years, engine manufacturers have been continuously involved in the research of proper technical solutions to meet more and more stringent CO2 emission targets, defined by international regulations. Many strategies have been already developed, or are currently under study, to attain the above objective. A tendency is however emerging towards more innovative combustion concepts, able to efficiently burn lean or highly diluted mixtures. To this aim, the enhancement of turbulence intensity inside the combustion chamber has a significant importance, contributing to improve the burning rate, to increase the thermal efficiency, and to reduce the cyclic variability. It is well-known that turbulence production is mainly achieved during the intake stroke. Moreover, it is strictly affected by the intake port geometry and orientation.In this paper, different geometries of the intake port are analyzed by means of a 3D-CFD approach, to foresee the flow evolution and tumble motion development during intake and compression strokes. Tumble vortex collapse and turbulence production at the end of the compression stroke are analyzed in detail, since turbulence levels just before TDC…
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Performance Improvement and Emission Control of a Dual Fuel Operated Diesel Engine

University of Naples Federico II - Italy-Maria Cristina Cameretti, Roberta De Robbio, Raffaele Tuccillo
Published 2017-09-04 by SAE International in United States
The present study deals with the simulation of a Diesel engine fuelled by natural gas/diesel in dual fuel mode to optimize the engine behaviour in terms of performance and emissions. In dual fuel mode, the natural gas is introduced into the engine’s intake system. Near the end of the compression stroke, diesel fuel is injected and ignites, causing the natural gas to burn. The engine itself is virtually unaltered, but for the addition of a gas injection system. The CO2 emissions are considerably reduced because of the lower carbon content of the fuel. Furthermore, potential advantages of dual-fuel engines include diesel-like efficiency and brake mean effective pressure with much lower emissions of oxides of nitrogen and particulate matter. In previous papers, the authors have presented some CFD results obtained by two 3D codes by varying the diesel/NG ratio and the diesel pilot injection timing at different loads. The calculations have been referred to a light duty direct injection diesel engine, of which some experimental data were available, obtained both in full diesel and Dual Fuel…
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Experimental and Numerical Characterization of Diesel Injection in Single-Cylinder Research Engine with Rate Shaping Strategy

Istituto Motori CNR-Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco
Univ of Napoli Federico II-Maria Cristina Cameretti
Published 2017-09-04 by SAE International in United States
The management of multiple injections in compression ignition (CI) engines is one of the most common ways to increase engine performance by avoiding hardware modifications and after-treatment systems. Great attention is given to the profile of the injection rate since it controls the fuel delivery in the cylinder. The Injection Rate Shaping (IRS) is a technique that aims to manage the quantity of injected fuel during the injection process via a proper definition of the injection timing (injection duration and dwell time). In particular, it consists in closer and centered injection events and in a split main injection with a very small dwell time.From the experimental point of view, the performance of an IRS strategy has been studied in an optical CI engine. In particular, liquid and vapor phases of the injected fuel have been acquired via visible and infrared imaging, respectively. Injection parameters, like penetration and cone angle have been determined and analyzed. The data have been collected by running an engine condition of the homologation cycle New European Driving Cycle (NEDC) with two…
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Dual Fuel Diesel Engine at Variable Operating Conditions: A Numerical and Experimental Study

Istituto Motori CNR-Sabato Iannaccone
Univ of Napoli Federico II-Carmelina Abagnale, Maria Cristina Cameretti, Umberto Ciaravola, Raffaele Tuccillo
Published 2015-09-06 by SAE International in United States
The dual-fuel (diesel/natural gas, NG) concept represents a solution to reduce emissions from diesel engines by using natural gas as an alternative fuel. As well known, the dual-fuel technology has the potential to offer significant improvements in the emissions of carbon dioxide from light-duty compression ignition engines. A further important requirement of the DF operation in automotive engines is a satisfactory response in a wide range of load levels. In particular, the part-load levels could present more challenging conditions for an efficient combustion development, due to the poor fuel/air ratio.Basing on the above assumptions, the authors discuss in this article the results of a combined numerical and experimental study on the effect of different injection timings on performance and pollutant fractions of a common rail diesel engine supplied with natural gas and diesel oil. The study of dual-fuel engines that is carried out in this paper aims at the evaluation of the CFD capability to analyze the main phenomena that characterize this particular technology. Actually, in order to put into evidence the key processes that…
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Experimental Investigation and Numerical Modelling of an Advanced Turbocharged D.I. Diesel Engine

Università di Napoli-Fabio Bozza, Maria Cristina Cameretti, Adolfo Senatore, Raffaele Tuccillo
Published 1997-02-24 by SAE International in United States
Following their recent experiences in the fields of experimental analysis and numerical simulation of turbocharged engines, the authors present, in this paper, an integrated procedure for studying the behaviour of a light-duty turbocharged D.I. diesel engine, equipped with a variable geometry turbine, an intercooler and an EGR system for NOx control.Experimental activities consist of a complete investigation of the engine operating conditions under different rotational speeds and fuel deliveries. Experimental data provide the basis for numerical investigations.Numerical simulation is carried out through different level of approach, characterised by an increasing level of complexity. A simplified approach of the filling and emptying type is employed for a preliminary determination of matching conditions among the components. Next, a 1-D flow model allows a more correct evaluation of wave propagation phenomena through external ducts.A more detailed insight of the in-cylinder phenomena is obtained by employing a multidimensional model (i.e., the well known KIVA II code) for examining the closed-valve period. The authors employ a recently proposed methodology for matching the results of 0-D and multidimensional simulation as to…
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