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Feasibility of Multiple Piston Motion Control Approaches in a Free Piston Engine Generator

West Virginia University-Mehar Bade, Nigel Clark, Parviz Famouri, PriyaankaDevi Guggilapu
  • Technical Paper
  • 2019-01-2599
To be published on 2019-10-22 by SAE International in United States
The control and design optimization of a Free Piston Engine Generator (FPEG) has been found to be difficult as each independent variable changes the piston dynamics with respect to time. These dynamics, in turn, alter the generator and engine response to other governing variables. As a result, the FPEG system requires an energy balance control algorithm such that the cumulative energy delivered by the engine is equal to the cumulative energy taken by the generator for stable operation. The main objective of this control algorithm is to match the power generated by the engine to the power demanded by the generator. In a conventional crankshaft engine, this energy balance control is similar to the use of a governor and a flywheel to control the rotational speed. In general, if the generator consumes more energy in a cycle than the engine provides, the system moves towards a stall. If the generator consumes less energy, then the effective stroke, compression ratio and maximum translator velocity must rise steadily from cycle-to-cycle until the heat transfer losses stop the…
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Engine Cylinder Head Thermal-Mechanical Fatigue Evaluation Technology and Platform Application

Jiangling Motor Company Limited, China-Xuwei Luo
Jiangling Motor Company, China-Xiaochun Zeng
  • Journal Article
  • 03-13-01-0008
Published 2019-10-14 by SAE International in United States
An in-cylinder combustion analysis and a computational fluid dynamics (CFD) coolant flow analysis were performed using AVL FIRE software, which provided the heat transfer boundary conditions (HTBCs) to the temperature field calculation of the cylinder head. Based on the measured material performance parameters such as stress-strain curve under different temperatures and E-N curve, creep, and oxidation data material performance, the cylinder head-gasket-cylinder block finite element analysis (FEA) was performed. According to the temperature field calculation results, the maximum temperature of the cylinder head is 200°C that is within the limit of ALU material. The temperature of the water is more than 21.1°C below the critical burnout point temperature. The high-cycle fatigue (HCF) and thermal-mechanical fatigue (TMF) analysis of the cylinder head were performed by FEMFAT software. The HCF safety coefficient and TMF life cycle of the cylinder head were calculated, which provided an important guidance for cylinder head structure design of a gasoline engine and diesel engine. The present article establishes a complete simulation and analysis process of cylinder head TMF. The fatigue assessment technology…
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CFD Simulation on Turbulent Forced Convection of Copper Oxide (CuO) -Water Nanofluids in a Horizontal Circular Pipe

John Deere India Pvt, Ltd.-Nitin Dewangan, Nitin Kattula
Published 2019-10-11 by SAE International in United States
The present study provides a detailed investigation on simulation of Copper oxide nanofluids in a simple horizontal circular pipe considering turbulent forced convection, with a constant heat flux boundary condition. The simulation is carried out using three different models available in fluent viz. Newtonian single phase model, Eulerian-mixture and Eulerian-Eulerian multiphase models. The Reynold number of the flow is varied along with volume concentration of nanoparticles varying form low to high. Nanofluids rheology is studied by considering standard k-ε two equation turbulence model with enhanced wall treatment considering appropriate wall y+ values. The effective temperature dependent thermo-physical properties for nanofluids were seized from the literatures. The results from the simulation clearly showed an increase in the heat transfer characteristics with the addition of nanoparticles compared to that of base fluid alone. Eulerian-Mixture model predicted the Nusselt number near to that of the experimental results from literature.
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ERRATUM

Université de Lyon-Charlotte Fossier, Christophe Changenet, Fabrice Ville
Volvo Group-Denis Barday, Vincent Berier
  • Journal Article
  • 03-11-01-0004.1
Published 2019-10-07
No Abstract Available.
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How to Improve SI Engine Performances by Means of Supercritical Water Injection

University of Basilicata – Potenza 85100-Antonio Cantiani, Annarita Viggiano, Vinicio Magi
Published 2019-10-07 by SAE International in United States
The efficiency of ICEs is strongly affected by exhaust gases and engine cooling system heat losses, which account for about 50% of the heat released by combustion. A promising approach is to transfer this exhaust heat to a fluid, like water, and inject it into the combustion chamber under supercritical conditions. In such a way, the recovered energy is partially converted into mechanical work, improving both engine efficiency and performance.A quasi-dimensional model has been implemented to simulate an SI engine with supercritical water injection. Specifically, a spark ignition ICE, four-stroke with Port Fuel Injection (PFI) has been considered. The model accounts for gas species properties, includes valves opening/closing, wall heat transfer, a water injection model and a combustion model. The influence of some injection parameters, i.e. Water/Fuel ratio (W/F), Start Of water Injection (SOI) and Water Injection Duration (WID), on engine performances and efficiency is discussed in details.The results show that an increase of W/F ratio has the strongest impact on the performances with respect to SOI and WID, i.e. higher W/F ratio, SOI closer…
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Performance and Emissions of an Advanced Multi-Cylinder SI Engine Operating in Ultra-Lean Conditions

Renault SA-Cédric LIBERT
University of Naples “Federico II”-Fabio Bozza, Daniela Tufano, Enrica Malfi, Luigi Teodosio, Vincenzo De Bellis
Published 2019-09-09 by SAE International in United States
In this work the performance and noxious emissions of a prototype Spark Ignition (SI) engine, working in ultra-lean conditions, are investigated. It is a four-cylinder engine, having a very high compression ratio, and an active pre-chamber. The required amount of air is provided by a low-pressure variable geometry turbocharger, coupled to a high-pressure E-compressor. The engine is equipped with a variable valve timing device on the intake camshaft.The goal of this activity is to support the development and the calibration of the described engine, and to exploit the full potential of the ultra-lean concept. To this aim, a combustion model for a pre-chamber engine, set up and validated in a previous paper for a similar single-cylinder unit, is utilized. It is coupled to additional in-house developed sub-models, employed for the prediction of the in-cylinder turbulence, heat transfer, knock and pollutant emissions.Such a complex architecture, schematized in a commercial 1D modeling framework, presents several control parameters which have to be properly selected to maximize the engine efficiency and minimize the noxious emissions over its whole operating…
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CFD Investigation of the Effects of Gas’ Methane Number on the Performance of a Heavy-Duty Natural-Gas Spark-Ignition Engine

Universita degli Studi di Perugia-Luca Ambrogi, Michele Battistoni, Lorenzo Gasbarro
West Virginia Univ.-Jinlong Liu, Cosmin Dumitrescu
Published 2019-09-09 by SAE International in United States
Natural gas (NG) is an alternative fuel for spark-ignition engines. In addition to its cleaner combustion, recent breakthroughs in drilling technologies increased its availability and lowered its cost. NG consists of mostly methane, but it also contains heavier hydrocarbons and inert diluents, the levels of which vary substantially with geographical source, time of the year and treatments applied during production or transportation. To investigate the effects of NG composition on engine performance and emissions, a 3D CFD model of a heavy-duty diesel engine retrofitted to NG spark ignition simulated lean-combustion engine operation at low speed and medium load conditions. The work investigated three NG blends with similar lower heating value (i.e., similar energy density) but different Methane Number (MN). The results indicated that a lower MN increased flame propagation speed and thus increased in-cylinder pressure and indicated mean effective pressure. In addition, a low MN increased the thermal efficiency despite the higher heat transfer to the surroundings. Also, a higher MN reduced the nitrogen-oxides emissions but increased unburned hydrocarbons (UHC) emissions. Moreover, while UHC emissions…
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Validation and Analysis of Heat Losses Prediction Using Conjugate Heat Transfer Simulation for an Internal Combustion Engine

CMT- Universitat Politècnica de València-Alberto Broatch, Xandra Margot, Jorge Garcia-Tiscar, Johan Escalona
  • Technical Paper
  • 2019-24-0091
Published 2019-09-09 by SAE International in United States
New technologies are required to improve engine thermal efficiency. For this it is necessary to use all the tools available nowadays, in particular computational tools, which allow testing the viability of different solutions at reduced cost. In addition, numerical simulations often provide more detailed information than experimental tests. Such is the case for the study of the heat transfer through the walls of an engine. Conjugate Heat Transfer (CHT) simulations permit precise calculations of the heat transfer from gas to walls throughout the whole engine cycle, and thus it is possible to know such details as the instantaneous heat losses and wall temperature distribution on the walls, which no experiment can give. Nevertheless, it is important to validate CHT calculations, either with some experimental measurements or with some other reliable tool, such as 0D-1D modelling known to work well.The proposed work is based on the CHT simulation of the heat transfer to the walls of an engine piston during an entire cycle to determine the parameters that permit obtaining good results. This will be ascertained…
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Design of a Hybrid Power Unit for Formula SAE Application: Packaging Optimization and Thermomechanical Design of the Electric Motor Case

University of Modena and Reggio Emilia-Valerio Mangeruga, Matteo Giacopini, Saverio Giulio Barbieri, Fabio Berni, Enrico Mattarelli, Carlo Rinaldini
Published 2019-09-09 by SAE International in United States
This paper presents the development of a parallel hybrid power unit for Formula SAE application. In particular, the system is made up of a brand new, single-cylinder 480 cc internal combustion engine developed on the basis of the Ducati “959 Superquadro” V90 2-cylinders engine. The thermal engine is assisted by a custom electric motor (30 kW), powered by a Li-Ion battery pack. The performance of the ICE has been optimized through CFD-1D simulation (a review of this activity is reported in a parallel paper). The main design goal is to get the maximum amount of mechanical energy from the fuel, considering the car typical usage: racing on a windy track. The Ducati “959 Superquadro” engine is chosen because of its high power-to-weight ratio, as well as for its V90 2-cylinder layout. In fact, the vertical engine head is removed and it is subsequently replaced by the electric motor directly engaged to the crankshaft using the original valvetrain transmission chain, thus achieving a very compact package. The mechanical behaviour of the original chain is investigated for…
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Optical Diagnostics Investigation on the Effect of Fuel Injection Timing on Partially Premixed Combustion Stratification and Soot Formation in a Single-Cylinder Optical Compression Ignition Engine

Imperial College London-Dimitrios P. Touloupis, George Vourliotakis, Christos Keramiotis, Kumara Gurubaran Ramaswamy, Yannis Hardalupas, Alexander Taylor
  • Technical Paper
  • 2019-24-0028
Published 2019-09-09 by SAE International in United States
The present work investigates the effect of fuel injection timing on combustion stratification and soot formation in an optically accessible, single cylinder light duty diesel engine. The engine operated under low load and low engine speed conditions, employing a single injection scheme. The conducted experiments considered three different injection timings, which promoted Partially Premixed Combustion (PPC) operation. The fuel quantity of the main injection was adjusted to maintain the same Indicated Mean Effective Pressure (IMEP) value among all cases considered. Findings were analysed via means of pressure trace and apparent heat transfer rate (AHTR) analyses, as well as a series of optical diagnostics techniques, namely flame natural luminosity, CH* and C2* chemiluminescence high-speed imaging, as well as planar Laser Induced Incandescence (pLII). For the chemiluminescence high-speed imaging a novel methodology was developed to acquire the net spatially resolved chemiluminescence signal, using combustion spectroscopy to remove the background chemiluminescence and thermal radiation signal. The analysis suggests that when the injection timing advanced, the stratification of the combustion became weaker, as indicated by the natural luminosity signal,…
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