Display:

Results

Viewing 1 to 30 of 56918
2017-04-11
Journal Article
2017-01-9625
Souhir Tounsi
Abstract In this paper, we present a design and control methodology of an innovated structure of switching synchronous motor. This control strategy is based on the pulse width modulation technique imposing currents sum of a continuous value and a value having a shape varying in phase opposition with respect to the variation of the inductances. This control technology can greatly reduce vibration of the entire system due to the strong fluctuation of the torque developed by the engine, generally characterizing switching synchronous motors. A systemic design and modelling program is developed. This program is validated following the implementation and the simulation of the control model in the simulation environment Matlab-Simulink. Simulation results are with good scientific level and encourage subsequently the industrialization of the global system.
2017-04-11
Book
This is the electronic format of the Journal.
2017-03-28
Technical Paper
2017-01-0852
Sathya prasad Potham, Le Zhao, Seong-Young Lee
This paper aims to present the results of numerical modeling and simulation of evaporation of single and multiple spherical n-heptane droplets impinging on a hot wall at a temperature above the Leidenfrost temperature at atmospheric pressure. Volume of Fluid (VOF) method is chosen for tracking the liquid gas interface and an open source CFD software, OpenFOAM, is chosen for modeling and simulations. The capability of VOF method implemented in interDyMFoam solver of OpenFOAM to simulate hydrodynamics during droplet-droplet interaction and droplet-film interaction is explored. The in-built solver is used to simulate problems in isothermal conditions and the simulation results are compared qualitatively with the published results to validate the solver. A numerical method for modeling heat and mass transfer during evaporation is implemented in conjunction with the VOF.
2017-03-28
Technical Paper
2017-01-1089
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Exhaust Gas Recirculation system (EGR) has been used for years for NOx emissions control in commercial vehicle applications. Emissions limits are tighter with every regulation while durability requirements are increasing, so EGR systems manufacturers must be able to provide high performance and robust designs even with high thermal loads. Commercial vehicle market is characterized by lower production rates than passenger car programs, but same engine has multiple applications with totally different engine calibrations. In some cases it is necessary to design two or more EGR systems for an engine platform, with the consequent impact on cost and development timeline. The optimal design of and EGR system needs to take into consideration several topics related with performance and durability: efficiency and pressure drop, fouling, boiling, thermal fatigue, vibrations, pressure fatigue and corrosion among others.
2017-03-28
Technical Paper
2017-01-0843
Jose Pastor, Jose M Garcia-Oliver, Antonio Garcia, Varun Reddy NAREDDY
Recent researches have shown that the use of highly premixed dual fuel combustion reduces pollutant emissions and fuel consumption in CI engines. The most common strategy for dual fueling is to use two injection systems. Port fuel injection for low reactivity fuel and DI for high reactivity fuel. This strategy implies some severe shortcomings for its real implementation in passenger cars such as the use of two fuel tanks. In this sense, the use of a single injection system for dual fueling could solve this drawback trying to maintain pollutant and efficiency benefits. Nonetheless, when single injection system is used, the spray characteristics become an essential issue. In this work the fundamental characteristics of dual-fuel sprays with a single injection system under evaporating engine-like conditions are presented.
2017-03-28
Technical Paper
2017-01-0836
Hongjiang Li, Christopher Rutland
Large eddy simulations coupled with two uncertainty quantification (UQ) methods, latin-hypercube sampling and polynomial chaos expansion, were carried out to quantify the effects of model parameters and spray initial and boundary conditions on spray development. Evaporating, non-reacting n-dodecane and iso-octane experimental spray data under typical diesel and gasoline engine-like conditions was used to compare penetration lengths and probability contours. Five spray initial and boundary conditions were used for single-hole n-dodecane sprays. The Morris one-step-at-a-time method was used to identify parameters with the highest impacts for multi-hole iso-octane sprays. The resulting four most important parameters, including two model parameters and two spray boundary conditions, were chosen for further study. Penetration lengths and corresponding standard deviations derived from both UQ methods were found to be quite similar with experiments.
2017-03-28
Technical Paper
2017-01-0638
Neerav Abani, Nishit Nagar, Rodrigo Zermeno, Michael chiang, Isaac Thomas
Heavy-duty vehicles, currently the second largest source of fuel consumption and carbon emissions are projected to be fastest growing mode in transportation sector in future. There is a clear need to increase fuel efficiency and lower emissions for these engines. The Achates Power Opposed-Piston Engine has the potential to address this growing need. In this paper, results will be presented for a 9.8L three-cylinder OP Engine that shows the potential of achieving 51%+ brake thermal efficiency (BTE), while simultaneously satisfying 4.0 g/kWhr engine out NOx and 0.01 g/kWhr engine-out soot. The OP Engine architecture can meet this performance without the use of additional technologies such as thermal barrier coatings, waste heat recovery or additional turbo-compounding.
2017-03-28
Technical Paper
2017-01-0826
Russell P. Fitzgerald, Christopher Gehrke, Kenth Svensson, Glen Martin
The performance of five positive k-factor injector tips has been assessed in this work by analyzing a comprehensive set of injected mass, momentum, and spray measurements. Using high speed shadowgraphs of the injected diesel plumes, the sensitivities of measured vapor penetration and dispersion to injection pressure (100-250MPa) and ambient density (20-52 kg/m3) have been compared with the Naber-Siebers empirical spray model to gain understanding of second order effects of orifice diameter. Varying in size from 137 to 353µm, the orifice diameters and corresponding injector tips are appropriate for a relatively wide range of engine cylinder sizes (from 0.5 to 5L). In this regime, decreasing the orifice exit diameter was found to reduce spray penetration sensitivity to differential injection pressure. The cone angle and k-factored orifice exit diameter were found to be uncorrelated.
2017-03-28
Technical Paper
2017-01-0787
Benedikt Von Imhoff, Markus Mühlthaler, Georg Wachtmeister
Improving efficiency and reducing emissions are the principal challenges in developing new generations of internal combustion engines. Different strategies are pursued like downsizing or sophisticated after-treatment of exhaust gases. Another approach gears forward to optimize the parameterization of the engine. Correct adjustments of ignition timings, waste gate position et cetera have significant influence on the combustion process. A multitude of application data is generated during the development process to predefine appropriate settings for most situations. Improvements regarding the application effort and the quality of the settings can be achieved by measuring the combustion process and optimizing the parametrization in a closed loop. However, cylinder pressure sensors that are used during the development process are too expensive for series applications.
2017-03-28
Technical Paper
2017-01-0785
Nicolo Cavina, Andrea Businaro, Matteo De Cesare, Luigi Paiano
In modern turbocharged downsized GDI engines the achievement of maximum combustion efficiency is precluded by the occurrence of knock. In-cylinder pressure sensors give the best performance in terms of abnormal combustion detection, but are affected by long term reliability issues and still constitute a considerable part of the entire engine management system cost. To overcome these problems, knock control strategies based on engine block vibrations or ionization current signals have been developed and are widely used in production control units. Furthermore, previous works have shown that engine sound emissions can be real-time processed to provide the engine management system with control-related information such as turbocharger rotational speed and knock intensity, demonstrating the possibility of using a multi-function device to replace several sensors.
2017-03-28
Technical Paper
2017-01-0786
Nicolo Cavina, Andrea Businaro, Matteo De Cesare, Federico Monti
Knock control systems based on engine block vibrations analysis are widely adopted in passenger car engines, but such approach shows its main limits at high engine speeds, since knock intensity measurement becomes less reliable due to the increased background mechanical noise. For small two wheelers engines, knock has not been historically considered a crucial issue, mainly due to small-sized combustion chambers and mixture enrichment. Due to more stringent emission regulations and in search of reduced CO2 emissions, an effective on-board knock controller acquires today greater importance also for motorcycle applications, since it could protect the engine when different fuel types are used, and it could significantly reduce fuel consumption (by avoiding lambda enrichment and/or allowing higher compression ratios to be adopted). These types of engines typically work at high rotational speeds and the reduced signal to noise ratio makes knock onset difficult to identify.
2017-03-28
Technical Paper
2017-01-0784
Nicolo Cavina, Nahuel Rojo, Luca Poggio, Lucio Calogero, Ruggero Cevolani
Pre-ignition combustions are extremely harmful and undesired, but the recent search for extremely efficient spark-ignition engines has implied a great increase of the in-cylinder pressure and temperature levels, forcing engine operation to conditions that may trigger this type of anomalous combustion much more frequently. For this reason, an accurate on-board diagnosis system is required to adopt protective measures, preventing engine damage. Ion current signal provides relevant information about the combustion process, and it results in a good compromise between cost, durability and information quality (signal to noise ratio levels). The GDI turbocharged engine used for this study was equipped with a production ion current sensing system, while in-cylinder pressure sensors were installed for research purposes, to better understand the pre-ignition phenomenon characteristics, and to support the development of an on-board diagnostic system solely based on ion current measurements.
2017-03-28
Technical Paper
2017-01-0789
Tobias Johansson, Ola Stenlaas
Typically the combustion in an internal combustion engine is open-loop controlled. The introduction of a cylinder pressure sensor opens the possibility to introduce a virtual combustion sensor. This virtual sensor is a possible enabler for closed-loop combustion control and thus the possibility to counteract effects as engine part to part variation, component ageing and fuel quality diversity. The extent to which these effects can be counteracted is determined by the detection limits of the virtual combustion sensor. To determine the limitation of the virtual combustion sensor a virtual combustion sensor system was implemented based on a one-zone heat-release analysis, including signal processing of the pressure sensor input. Typical error sources in a heavy-duty engine were identified and quantified. The virtual combustion sensor system was presented with flawed signals and the sensors sensitivities to the errors were quantified.
2017-03-28
Technical Paper
2017-01-0790
Valentin Soloiu, Remi Gaubert, Martin Muinos, Jose Moncada, Thomas Beyerl, Gustavo Molina
A diesel common rail fuel injection system for an experimental research engine has been designed and developed through testing the hydraulic, electrical, mechanical subcomponents, and the controls strategies. This study presents the process taken based on the verification and validation model of design and development for a fuel injection system incorporating hardware-in-the-loop (HIL) testing prior to engine operation and engine testing. Software verification was completed through signal converting circuits to confirm precise injection timing and to test the system in a mean effective model to incorporate a PID speed controller along with consistent rail pressure. Initial operation of the common rail system integrated on the direct injected single-cylinder medium duty engine resulted in flexible combustion schemes with various injection timings and split patterns at a constant speed of 1500 RPM and 4.2 IMEP.
2017-03-28
Technical Paper
2017-01-0620
Chandrakant Parmar, Sethuramalingam Tyagarajan, Sashikant Tiwari, Ravindra Thonge, S Arun Paul
The engine compartment of passenger car application contain various source which radiates the produced heat and raises the temperature level of the compartment. The rise in compartment temperature increases the individual component body temperature. The rise in body temperature of critical components can endanger the life or functionality of the specific component or a system in which it operates. The aim of this paper is to strategise thermal protection of the rear mounted engine and it's components of a vehicle having radiator and cooling fan mounted in front. An additional ventilation fan with speed sensor is fitted alongside rear mounted engine and a unique monitoring technique framed in the EMS ECU to protect critical components like HT cables, alternators, ECU, wiring harness etc. from thermal damage. The EMS continuously monitors the engine speed, vehicle speed and the PWM signal of ventilation fan to ensure the intended operation of the ventilation fan.
2017-03-28
Technical Paper
2017-01-0628
Rahul Fageria, Satvik Jain
Turbochargers have become an inevitable part of modern engines for their ability to improve an engine's efficiency and power output through forced induction using the exhaust gas energy which otherwise would have been wasted. And with their use, there is always some unwanted heat as a by-product. For that, turbo intercoolers are employed, they reduce the temperature of the forced air before reaching the engine and improve their volumetric efficiency by increasing intake air charge density through an isobaric cooling. The forced air produced by the turbocharger is routed through the intercooler where its temperature is reduced before reaching the engine. Intercoolers also eliminate the need for using the wasteful method of lowering intake charge temperature by the injection of excess fuel into the cylinders' air induction chambers, to cool the intake air charge, prior to its flowing into the cylinders.This has made modern heavy duty diesel vehicles far more efficient.
2017-03-28
Technical Paper
2017-01-0636
Vijai Shankar Bhavani Shankar, Nhut Lam, Arne Andersson, Bengt Johansson
The concept of double compression, and double expansion stages (DCEE) for improving the efficiency of piston reciprocating engines was introduced in SAE Paper 2015-01-1260. This engine configuration separates high, and low pressure units thereby effectively reducing friction losses. The presence of an additional expander stage also allows an extra degree of freedom to manipulate the combustion heat release rate so as to achieve better optimum between heat transfer, and friction losses. This paper presents a 1-D modeling study of the engine concept in GT-Power for assessing the sensitivity of engine losses to heat release rate at a given speed-load point. The simulations were constrained by limiting the range of maximum motoring pressures from 200 bar to 300 bar, and the maximum pressure during combustion to 300 bar. The maximum motor pressure was varied by constraining the compression ratio of the high pressure unit and adapting the low pressure unit accordingly.
2017-03-28
Technical Paper
2017-01-0637
Yan Zhang, Ziyu Wang, Honglin Bai PhD, Chao Guo, Jinlong liu, Yufeng Li
Mechanical load and thermal load are the two main barriers limiting the engine power output of the HD diesel engines. Usually, the peak cylinder pressure could be reduced by retarding combustion phasing while introducing the drawback of higher thermal load and exhaust temperature. In this paper, Miller cycle with late intake valve closing was investigated at high speed high load condition on a single cylinder HD diesel engine. The results showed the simultaneous reduction of mechanical and thermal loads. In the meanwhile, higher boosting pressure was required to compensate the Miller loss of the intake charge during intake and compression process. The combustion temperature, cylinder pressure, exhaust temperature, NOx emission and smoke number were reduced significantly with Miller cycle at the operating condition. Furthermore, the combustion process and thermodynamic efficiencies were analysed.
2017-03-28
Technical Paper
2017-01-0644
Michael Pontoppidan, Adm José baeta
Vehicle emissions significantly increase the atmospheric air pollution and the green house gas (GHG) effect. This fact together with a fast global vehicle fleet growth requires a scientific technological solution, which introduces a significant reduction of vehicle fleet fuel consumption and emission to comply with future legislation. As a response to this requirement a prototype engine equipped with a torch ignition system and designed for stratified mixture conditions was made. The design is based on a commercial baseline engine layout. In this system, the combustion starts in a pre-chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The combustion jet flames have high thermal and kinetic energy being able to promote a stable lean combustion process through enhanced mixture stratification.
2017-03-28
Technical Paper
2017-01-0715
Peter Luning Prak, Len Hamilton, Dianne Luning-Prak, Jim Cowart
Primary diesel and gasoline reference fuels, along with secondary reference diesel fuels across a very broad cetane range were tested in an Ignition Quality Tester (IQT) rig. Additionally, numerous pure component fuels across a range of hydrocarbon size and structure were evaluated. Various methods were used to determine the Ignition Delay (IGD) of the various fuels. All of this testing followed the ASTM D6890 protocol. The reference fuels’ IGD followed expected trends, however, the diesel PRF fuels in the low cetane range produced DCNs (Derived Cetane Numbers) that were moderately higher than their cetane reference values. From the perspective of fuel size, IGD shows a significant ‘shortening’ – faster nature with increased fuel carbon number. For a given carbon number fuel molecule, normal alkanes were provided the ‘fastest’ IGD, with alkenes and branched aromatics leading to moderately longer IGDs. Cyclo-paraffins show the ‘slowest’ – longest IGDs.
2017-03-28
Technical Paper
2017-01-0710
Yilong Zhang, Renlin Zhang, Lingzhe Rao, Sanghoon Kook
Soot particles emitted from modern diesel engines, despite significantly lower total mass, show higher reactivity and toxicity than black-smoking old engines, which cause serious health and environmental issues. Soot nanostructure, i.e. the internal structure of soot particles composed of nanoscale carbon fringes, can provide useful information to the investigation of the particle reactivity and its oxidation status. This study presents the nanostructure details of soot particles sampled directly from diesel flames in a working diesel engine as well as from exhaust gases to compare the internal structure of soot particles in the high formation stage and after in-cylinder oxidation. Thermophoretic soot sampling was conducted using an in-house-designed probe with a lacy transmission electron microscope (TEM) grid stored at the tip.
2017-03-28
Technical Paper
2017-01-0706
Gen Shibata, Hideyuki Ogawa, Yuki Okamoto, Yasumasa Amanuma, Yoshimitsu Kobashi
The premixed diesel combustion is effective for the high thermal efficiency and the reduction of NOx and PM emissions, but the reduction of combustion noise is necessary at medium-high load operation. The control of the fuel injection becomes more accurate than previous because of the technical progress of the common rail fuel injection systems, and the target heat release phase, calculated by computation, can be achieved by the controls of EGR, boosting, injection timing, and injection quantity of multiple fuel injections. In this paper, the reduction of premixed diesel combustion noise with keeping high thermal efficiency has been investigated by the control of multiple fuel injections. The research was approached from both the engine simulations and the experiments.
2017-03-28
Technical Paper
2017-01-0701
Aaron M. Bertram, Song-Charng Kong
The objective of this work was to identify methods of reliably predicting optimum operating conditions in an experimental compression ignition engine using multiple injections. Abstract modeling offered an efficient way to predict large volumes data, when compared with simulation, although the initial cost of constructing such models can be large. This work aims to reduce that initial cost by adding knowledge about the favorable network structures and training rules which are discovered. The data were gathered from a high pressure common rail direct injection turbocharged compression ignition engine utilizing a high EGR configuration. The range of design parameters were relatively large; 100MPa - 240 MPa for fuel pressure, up to 62% EGR while the pilot timing, main timing, and pilot ratio were free within the safe operating window for the engine.
2017-03-28
Technical Paper
2017-01-0660
Arturo Iacobacci, Luca Marchitto, Gerardo Valentino
Despite the continuous advancement of spark ignition engine technology, further solutions are under investigation to improve fuel efficiency and meet worldwide CO2 emissions regulation. Currently, engine manufacturers have focused on engine downsizing to improve efficiency of fuel combustion with the introduction of turbocharger or higher compression ratio engines that have the drawback to run the engine at delayed spark advance or richer mixture due to the knock occurrence. In this paper, the water injection technology was examined with the aim to reduce the air-fuel charge temperature to enhance the knock limit. The potential benefits of this technology were investigated on a downsized PFI twin-cylinder turbocharged spark ignition engine, by installing an additional port fuel injection system. The engine was run at high load condition (~15.5 bar IMEP) within the engine speed range from 3500 to 4500rpm.
2017-03-28
Technical Paper
2017-01-0663
Jeremy Worm, Jeffrey Naber, Joel Duncan, Sam Barros, William Atkinson
In a Spark-Ignited engine, there will come a point, as load is increased, where the unburned air-fuel mixture undergoes auto-ignition (knock). The onset of knock represents the upper limit of engine output, and limits the extent of engine downsizing / boosting that can be implemented for a given application. Although effective at mitigating knock, requiring high octane fuel is not an option for most markets. Retarding spark timing can extend the high load limit incrementally, but is still bounded by limits for exhaust gas temperature, and spark retard results in a notable loss of efficiency. Likewise, enriching the air-fuel mixture also decreases efficiency, and has profound negative impacts on engine out emissions. In this current work, a Direct-Injected, Boosted, Spark-Ignited engine with Variable Valve Timing was tested under steady state high load operation. Comparisons were made among three fuels; an 87 AKI, a 91 AKI, and a 110 AKI off-road only race fuel.
2017-03-28
Technical Paper
2017-01-0657
Lewis Gene Clark, Sanghoon Kook, Qing Nian Chan, Evatt R. Hawkes
This study investigates the effect of injection timing on the high-load combustion performance of a split-injection strategy in a spark-ignition direct-injection (SIDI) engine. Performance parameters derived from in-cylinder pressure data are analysed alongside high-speed natural flame luminosity images in order to obtain relationships between engine output and flame propagation behaviour. Trends in parameters such as indicated mean effective pressure (IMEP) and total heat release are found to be multimodal; as early injections aid the mixture formation process whereas late injections may lead to an increase in turbulence intensity at the point of ignition. Analysis of the high-speed images provides a further explanation of the observed results through investigating flame propagation speed and global eccentricity (i.e. non-circularity).
Viewing 1 to 30 of 56918

Filter