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Viewing 1 to 30 of 121
2010-10-25
Journal Article
2010-01-2165
David Serrano, Olivier Laget, Dominique Soleri, Stephane Richard, Benoit Douailler, Frederic Ravet, Marc Moreau, Nathalie Dioc
The introduction of alternative fuels is crucial to limit greenhouse gases. CNG is regarded as one of the most promising clean fuels given its worldwide availability, its low price and its intrinsic properties (high knocking resistance, low carbon content...). One way to optimize dedicated natural gas engines is to improve the CNG slow burning velocity compared to gasoline fuel and allow lean burn combustion mode. Besides optimization of the combustion chamber design, hydrogen addition to CNG is a promising solution to boost the combustion thanks to its fast burning rate, its wide flammability limits and its low quenching gap. This paper presents an investigation of different methane/hydrogen blends between 0% and 40 vol. % hydrogen ratio for three different combustion modes: stoichiometric, lean-burn and stoichiometric with EGR.
2010-04-12
Technical Paper
2010-01-1311
Maxime Debert, Guillaume Colin, Yann Chamaillard, Michel Mensler, Ahmed Ketfi-cherif, Lino Guzzella
The energy management of a hybrid vehicle defines the vehicle power flow that minimizes fuel consumption and exhaust emissions. In a combined hybrid the complex architecture requires a multi-input control from the energy management. A classic optimal control obtained with dynamic programming shows that thanks to the high efficiency hybrid electric variable transmission, energy losses come mainly from the internal combustion engine. This paper therefore proposes a sub-optimal control based on the maximization of the engine efficiency that avoids multi-input control. This strategy achieves two aims: enhanced performances in terms of fuel economy and a reduction of computational time.
2010-05-05
Journal Article
2010-01-1537
Michael Deligant, Pierre Podevin, Georges Descombes, Fabrice Vidal, Alain Lefebvre, Thierry Lamquin
Fuel consumption in internal combustion engines and their associated CO2 emissions have become one of the major issues facing car manufacturers everyday for various reasons: the Kyoto protocol, the upcoming European regulation concerning CO2 emissions requiring emissions of less than 130g CO2/km before 2012, and customer demand. One of the most efficient solutions to reduce fuel consumption is to downsize the engine and increase its specific power and torque by using turbochargers. The engine and the turbocharger have to be chosen carefully and be finely tuned. It is essential to understand and characterise the turbocharger's behaviour precisely and on its whole operating range, especially at low engine speeds. The characteristics at low speed are not provided by manufacturers of turbochargers because compressor maps cannot be achieve on usual test bench.
2010-05-05
Journal Article
2010-01-1555
Guillaume Latouchent, PIerre Darcy, Bertrand Coulet
This study deals with a coupled experimental and modeling approach of Diesel Particulate Filter cracking. A coupled model (heat transfer, mass transfer, chemical reactions) is used to predict the temperature field inside the filter during the regeneration steps. This model consists of assembled 1D models and is calibrated using a set of laboratory bench tests. In this set of experiments, laboratory scale filters are tested in different conditions (variation of the oxygen rate and gas flow) and axial/radial thermal gradient are recorded with the use of thermocouples. This model is used to build a second set of laboratory bench tests, which is dedicated to the understanding of the phenomena of Diesel Particulate Filter cracking.
2011-04-12
Technical Paper
2011-01-0197
Jean-Louis Ligier, Laurent Dutfoy
For many years, bearing suppliers have been using the specific pressure to evaluate the fatigue risk of conrod bearings. However, modern engines have made the bearing more sensitive to various phenomena such as the thermal expansion or the elasticity of the conrod housing. These effects modify the stresses in the bearing layers and consequently fatigue risk. In this paper, we propose a new way to determine the bearing fatigue resistance. To achieve that, we analyze the elastic and plastic behavior of the bearing along the engine life. We detail and provide the analytical relationships which determine stresses in the overlay and in the substrate of the bearing in order to analyze their fatigue resistance. Various physical loads are taken into account such as the thermal load, the hydrodynamic pressure field, the fitting load, the free spread load. A good knowledge of the relationships between those physical phenomena helps to understand the mechanical behavior of the bearing.
2010-04-12
Technical Paper
2010-01-0844
Florence Duffour, Vincent Knop, Franck Vangraefschepe, Thomas Leone, Vincent Pascal
Among the existing concepts that help to improve the efficiency of spark-ignition engines at part load, Controlled Auto-Ignition™ (CAI™) is an effective way to lower both fuel consumption and pollutant emissions. This combustion concept is based on the auto-ignition of an air-fuel-mixture highly diluted with hot burnt gases to achieve high indicated efficiency and low pollutant emissions through low temperature combustion. To minimize the costs of conversion of a standard spark-ignition engine into a CAI engine, the present study is restricted to a Port Fuel Injection engine with a cam-profile switching system and a cam phaser on both intake and exhaust sides. In a 4-stroke engine, a large amount of burnt gases can be trapped in the cylinder via early closure of the exhaust valves. This so-called Negative Valve Overlap (NVO) strategy has a key parameter to control the amount of trapped burnt gases and consequently the combustion: the exhaust valve-lift profile.
2004-03-08
Technical Paper
2004-01-1473
Brian J. Bowers, Jian L. Zhao, Druva Dattatraya, Vincent Rizzo, Fabien Boudjemaa
Reduction of pollutants and greenhouse gas emissions is one of the main objectives of car manufacturers and innovative solutions have to be considered to achieve this goal. Electric vehicles, and in particular Fuel Cell Electric Vehicles, appear to be a promising alternative. Renault is therefore investigating the technical and economic viability of a Fuel Cell Electric Vehicle (FCEV). A basic question of this study is the choice of the fuel that will be used for this kind of vehicle. Liquid fuels such as gasoline, diesel, naphtha, and gas-to-liquid can be a bridge for the introduction of fuel cell technologies while hydrogen infrastructure and storage are investigated. Therefore, multi-fuel Fuel Processor Systems that can convert liquid fuels to hydrogen while meeting automotive constraints are desired. Renault and Nuvera have joined forces to tackle this issue in a 3-year program where the objective is to develop and to integrate a Fuel Processor System (FPS) on a vehicle.
2004-06-08
Technical Paper
2004-01-1924
Robert Edwards, Vincent Mahieu, Jean-Claude Griesemann, Jean-François Larivé, David J. Rickeard
A consortium of CONCAWE, EUCAR and the EU Commission's JRC carried out a Well-to-Wheels analysis of a wide range of automotive fuels and powertrains. The study gives an assessment of the energy consumption and greenhouse gas emissions for each pathway. It also considers macroeconomic costs and the market potential of alternative fuels.
2004-06-08
Technical Paper
2004-01-1904
Pierre Duret, Bertrand Gatellier, Luis Monteiro, Marjorie Miche, Peter Zima, Damien Maroteaux, Jacky Guezet, David Blundell, Fritz Spinnler, Hua Zhao, Matteo Perotti, Lucio Araneo
The purpose of the European « SPACE LIGHT » (Whole SPACE combustion for LIGHT duty diesel vehicles) 3-year project launched in 2001 is to research and develop an innovative Homogeneous internal mixture Charged Compression Ignition (HCCI) for passenger cars diesel engine where the combustion process can take place simultaneously in the whole SPACE of the combustion chamber while providing almost no NOx and particulates emissions. This paper presents the whole project with the main R&D tasks necessary to comply with the industrial and technical objectives of the project. The research approach adopted is briefly described. It is then followed by a detailed description of the most recent progress achieved during the tasks recently undertaken. The methodology adopted starts from the research study of the in-cylinder combustion specifications necessary to achieve HCCI combustion from experimental single cylinder engines testing in premixed charged conditions.
2011-04-12
Journal Article
2011-01-1307
David Marie-Luce, Damiano Di-penta, Pierre-Alexandre Bliman, Michel Sorine
Lean NOx trap (LNT) and Selective Catalytic Reduction catalysts (SCR) are two leading candidates for diesel NOx after-treatment. Each technology exhibits good properties to reduce efficiently diesel NOx emissions in order to match the forthcoming EURO 6 standards. NOx reduction in LNT is made through a two-step process. In normal (lean) mode, diesel engine exhausts NOx is stored into the NOx trap; then when necessary the engine runs rich during limited time to treat the stored NOx. This operating mode has the benefit of using onboard fuel as NOx reducer. But NOx trap solution is restrained by limited active temperature windows. On the other hand, NH₃-SCR catalysts operate in a wider range of temperature and do not contain precious metals. However, NH₃-SCR systems traditionally use urea-water solution as reducing agent, requiring thus additional infrastructure to supply the vehicles with enough reducer.
2011-04-12
Technical Paper
2011-01-1300
Damiano Di-Penta, Karim Bencherif, Pierre-Yves Le-Morvan
This paper presents an after-treatment architecture combining a close coupled NOx trap and an under floor NOx trap. Instead of simply increasing the volume of the catalyst, we propose to broaden the active temperature window by splitting the LNT along the exhaust line. In order to design this architecture, a complete 1D model of NOx trap has been developed. Validated with respect to experimental data, this model has been useful to define the two volumes of LNT, making significant savings on the test bench exploitation. However, one of the main difficulties to operate the proposed architecture is the NOx purge and sulfur poisoning management. In order to optimize the NOx and sulfur purge launches, we have developed a control strategy based on an embedded reduced LNT model. These strategies have been validated on different driving cycles, by the means of simulation and of vehicle tests using rapid prototyping tools.
2011-08-30
Journal Article
2011-01-1893
Maria Rivas, Pascal Higelin, Christian Caillol, Olivier Sename, Emmanuel Witrant, Vincent Talon
To improve the prediction of the combustion processes in spark ignition engines, a 0D flame/wall interaction submodel has been developed. A two-zones combustion model is implemented and the designed submodel for the flame/wall interaction is included. The flame/wall interaction phenomenon is conceived as a dimensionless function multiplying the burning rate equation. The submodel considers the cylinder shape and the flame surface that spreads inside the combustion chamber. The designed function represents the influence of the cylinder walls while the flame surface propagates across the cylinder. To determine the validity of the combustion model and the flame/wall interaction submodel, the system was tested using the available measurements on a 2 liter SI engine. The model was validated by comparing simulated cylinder pressure and energy release rate with measurements. A good agreement between the implemented model and the measurements was obtained.
2000-03-06
Technical Paper
2000-01-0832
Oscar Martinez Garcia, Keyvan Kargar
2000-03-06
Technical Paper
2000-01-0914
Francisco Payri, José Galindo, Vicente Bermudez, Philippe Gutierrez, Hervé Mathieu
The purpose of this paper is to present the results of a study on the exhaust junctions geometry. Twelve three-branch junctions of different geometry have been tested on a single cylinder engine. The parameters studied have been exhaust junction outlet-to-inlet diameter ratio, length, angle between inlet branches and the existence of a reed separating inlet branches. An analysis of the pressure waves amplitude (incident, reflected and transmitted) obtained from instantaneous pressure measurements in some locations around the junction has been carried out. The analysis of results shows that junction length has a low influence on its behavior. The ratio between inlet and outlet branches diameters increases both reflection and directionality (avoiding pressure wave transmission to the adjacent branch). The existence of a reed separating the inlet flows may increase directionality with moderate pressure losses if the throat area is not reduced.
1999-10-25
Technical Paper
1999-01-3655
Stéphane Ledoyen, Christophe Dumouchel, Christophe Preterre
This paper presents an investigation on the experimental determination of some characteristics of the flow issuing from a swirl injector dedicated to direct-injection spark-ignited engines. The reproducibility, from one injection to another, of the temporal evolution of the liquid flow characteristics during the opening of the injector was investigated. This was achieved by using a high-speed film camera set at 8,000 images/s. The resulting visualizations allowed us to measure the evolution of the penetration length and velocity as well as of the liquid cone angle. It was found that the spray produced is a low momentum spray whose penetration length and velocity are small. The good reproducibility of the temporal evolution of the liquid flow characteristics has been obtained, except for the liquid cone angle during the opening stage. A fast-shutter video camera was also used to make images of the early development of the issuing liquid flow.
1999-09-28
Technical Paper
1999-01-3169
E. DiPasquale, J.-L. Duval, F. El Khaldi
This paper presents the application of the different approaches available for the analysis of the sheet metal forming process on an industrial part (RENAULT KANGOO front fender). It is nowadays accepted in the engineering community that inverse, simplified direct and incremental direct approach are complementary and should be used in the development of a stamped part. The paper shows the formability analysis of the TWINGO door and hatchback at different stages of the part and process design, identifies the optimal approach at different stages and gives indication as to the relative speed, accuracy and quality of the different simulation solutions.
2000-03-06
Technical Paper
2000-01-0292
Andrei K. da Silva, Michel Lebrun, Sébastien Samuel
In the analysis of a cooling network, Computational Fluid Dynamics methods show an unquestionable usefulness. Nevertheless, this approach is largely limited for simulating the behavior of multidisciplinary components connected in a system. The lumped parameter approach suits these systems simulation. This awareness has led to the development of methods for structuring these kinds of problems. Applying the multiport method, the Thermal, Thermal-hydraulic and Cooling system libraries were created. These libraries comprise a set of basic and specific components from which it is easy to model large thermal-hydraulic and engine cooling networks. These basic and specific elements facilitate the study of phenomena whose knowledge is indispensable for the analysis of a whole system. An application of these libraries to a RENAULT car is presented.
2000-03-06
Technical Paper
2000-01-0293
Michel Lebrun, Renaud Meillier, Lionel Broglia Patron, Sébastien Samuel
The modeling of thermal phenomena in transient state in a vehicle, typically the studies of heat exchanges in the engine or the heat exchange in the exhaust line leads to the use of nodal methods or lumped parameters in systems approach. This lumped parameters vision has led to important formalization studies these past years leading to two important concepts: the multiport concept of which bond-graphs constitute the theoretical framework, and the polymorphic modeling concept leading to the definition of a minimum of basic elements allowing to build a maximum of situations. This article proposes to demonstrate how these concepts have been used to bring about the development of a library of basic elements. Its application is demonstrated by the modeling of the different modules composing the engine (lubrication, cooling, exhaust and metal masses).
2011-06-09
Technical Paper
2011-37-0029
Sergio Hoyas, Jose M. Pastor, Dung Khuong-Anh, Juan Manuel Mompó-Laborda, Frederic Ravet
During the last fifteen years, Computational Fluid Dynamics (CFD) has become one of the most important tools to both understand and improve the diesel spray development in Internal Combustion Engine (ICE). Most of the approaches and models used pure Eulerian or Lagrangian descriptions to simulate the spray behavior. However, each one of them has both advantages and disadvantages in different regions of the spray, it can be the dense zone or the downstream dilute zone. One of the most promising techniques, which has been in development since ten years ago, is the Eulerian-Lagrangian Spray Atomization (ELSA) model. This is an integrated model for capturing the whole spray evolution, including primary break-up and secondary atomization. In this paper, the ELSA numerical modeling of diesel sprays implementation in Star-CD (2010) is studied, and simulated in comparison with the diesel spray which has been experimentally studied in our institute, CMT-Motores Térmicos.
2005-04-11
Technical Paper
2005-01-0220
P.-A. Beau, M. Funk, R. Lebas, F.-X. Demoulin
Atomizing systems must be able to form sprays with predetermined characteristics. There are affected by the shape of the injector as well as external conditions. Thus, in order to avoid numerous experiments, this is necessary to develop predictive atomization models able to deal with the complete atomization process. This can be done using a Eulerian model for primary break-up. This approach describes the flow continuously from inside the injector to the dispersed spray region. In this paper the Eulerian multiphase approach and the Eulerian single-phase approach are compared and the results lead to an intermediate quasi-multiphase approach for describing the spray core. Finally a transition zone permits to represent the diluted spray region by using the classical Lagrangian approach to benefit of the experience accumulated on this method, in particular for the vaporization and the combustion.
2005-04-11
Technical Paper
2005-01-0190
Stéphane Raux, Laurent Forti, S. Barbusse, G. Plassat, L. Pierron, R. Monier, J. C. Momique, C. Pain, B. Dionnet, E. Zervas, P. Rouveirolles, P. Dorlhene
An extensive research program involving the French passenger car and heavy-duty (HD) vehicles manufacturers, sponsored by ADEME and realized by IFP, aimed to characterize in terms of size and composition the particulate emitted by the different engine technologies currently or soon available. The impact of engine settings and fuel composition was also studied. Numerous information was collected in this HD study revealing that fuel composition and particularly non-conventional fuels and engine settings strongly impact the particulate concentration and size distribution. Nucleation is likely to occur when there is less adsorption matter, for instance when post-injection is used or EGR is removed. Particulate composition, particularly PAH and sulfates content, is weakly bound to the size. Mineral elements distribution depends on their origin, lubrication oil or engine wear.
2010-05-05
Journal Article
2010-01-1513
Vivien Delpech, Jerome Obiols, Dominique Soleri, Laurent Mispreuve, Eric Magere, Sebastien Kermarrec
In order to address the CO₂ emissions issue and to diversify the energy for transportation, CNG (Compressed Natural Gas) is considered as one of the most promising alternative fuels given its high octane number. However, gaseous injection decreases volumetric efficiency, impacting directly the maximal torque through a reduction of the cylinder fill-up. To overcome this drawback, both independent natural gas and gasoline indirect injection systems with dedicated engine control were fitted on a RENAULT 2.0L turbocharged SI (Spark Ignition) engine and were adapted for simultaneous operation. The main objective of this innovative combination of gas and liquid fuel injections is to increase the volumetric efficiency without losing the high knocking resistance of methane.
2010-05-05
Technical Paper
2010-01-1493
Nicolas Bordet, Christian Caillol, Pascal Higelin, Vincent Talon
This paper presents a new 0D phenomenological approach to predict the combustion process in diesel engines operated under various running conditions. The aim of this work is to develop a physical approach in order to improve the prediction of in-cylinder pressure and heat release. The main contribution of this study is the modeling of the premixed part of the diesel combustion with a further extension of the model for multi-injection strategies. In phenomenological diesel combustion models, the premixed combustion phase is usually modeled by the propagation of a turbulent flame front. However, experimental studies have shown that this phase of diesel combustion is actually a rapid combustion of part of the fuel injected and mixed with the surrounding gas. This mixture burns quasi instantaneously when favorable thermodynamic conditions are locally reached. A chemical process then controls this combustion.
2012-06-13
Journal Article
2012-01-1523
Louis HUMBERT, P. Pellerey, S. Cristaudo
RENAULT aims to become the first full-line manufacturer putting to market zero-emission affordable electrical vehicles and is therefore developing 100 % electric powertrains. NVH problems related to electric machine design have nothing in common with those of gasoline or diesel engines: electric whistling is a high frequency harmonic phenomenon, easily detectable due to the low background noise of a non-thermal vehicle and mainly perceived as very unpleasant by the customer. Therefore we have developed a coupled numerical simulation between electromagnetic and structural models, making it possible to understand the influence of magnetic parts design on noise and vibration level. Impact of the spatial and time coherence between magnetic pressures and vibration modes of the motor will be explained. The novelty of our approach is to already take into account the whole powertrain structure radiation, including reducer and power supply boxes.
2016-04-05
Technical Paper
2016-01-0554
José Galindo, Andrés Tiseira, Roberto Navarro, Daniel Tarí, Hadi Tartoussi, Stéphane Guilain
Abstract 0D-1D codes allow researchers to obtain a prediction of the behavior of internal combustion engines with little computational effort. One of the submodels of such codes is devoted to the centrifugal compressor. This model is often based on the compressor performance maps, therefore requiring the extrapolation of the maps so that all possible operating conditions are covered. Particularly, a suitable extrapolation of isentropic efficiency map is sought. This work first examines different available methods for compressor efficiency extrapolation into off-design conditions. No method is found to provide satisfactory results at all extrapolated regions: low and high compressor speeds and low compression ratio at measured speeds. Hence, a new method is proposed and its accuracy is assessed with the aid of compressor off-design measurements.
2016-04-05
Technical Paper
2016-01-0562
Hassan Karaky, Gilles Mauviot, Xavier Tauzia, Alain Maiboom
Abstract Due to its harmful effect on both human health and environment, soot emission is considered as one of the most important diesel engine pollutants. In the last decades, the industrial engine manufacturers have been able to strongly reduce its engine-out value by many different techniques, in order to respect the stricter emission norms. Simulation modeling has played and continues to play a key role for this purpose in the engine control system development. In this context, this paper proposes a new soot emission model for a direct injection diesel engine. This soot model is based on a zero-dimensional semi-physical approach coupled with a crank-angle resolved combustion model and a thermodynamic calculation of the burned gas products temperature. Furthermore, a multi linear regression model has been used to estimate the soot emissions as function of significant physical combustion parameters.
2015-04-14
Journal Article
2015-01-1746
Hassan Karaky, Gilles Mauviot, Xavier Tauzia, Alain Maiboom
Abstract Reducing NOx tailpipe emissions is one of the major challenges when developing automotive Diesel engines which must simultaneously face stricter emission norms and reduce their fuel consumption/CO2 emission. In fact, the engine control system has to manage at the same time the multiple advanced combustion technologies such as high EGR rates, new injection strategies, complex after-treatment devices and sophisticated turbocharging systems implemented in recent diesel engines. In order to limit both the cost and duration of engine control system development, a virtual engine simulator has been developed in the last few years. The platform of this simulator is based on a 0D/1D approach, chosen for its low computational time. The existing simulation tools lead to satisfactory results concerning the combustion phase as well as the air supply system. In this context, the current paper describes the development of a new NOx emission model which is coupled with the combustion model.
2015-04-14
Technical Paper
2015-01-1698
Balamurugan Rathinam, Frederic Ravet, Cedric Servant, Laurent Delahaye, Upendra Naithani
This paper is focused on the experimental and numerical investigation of tumble motion on a single cylinder optical engine on three important parameters like engine load conditions, engine speed and level of tumble. Experiments are conducted in an optical engine and the velocity fields are measured with the aid of advanced particle image velocimetry (PIV) measurement technique. For simulation, multiple cases were considered to develop the numerical process for transient in-cylinder aerodynamics to capture the tumble motion and turbulence level in a Spark Ignited (SI) engine. The simulation results, velocity fields of each case were directly compared with the corresponding test results for different crank positions of the engine. On comparison, a good agreement between the measurement and the simulation is obtained for different configurations.
2015-04-14
Journal Article
2015-01-0830
Jesus Benajes, Ricardo Novella, Daniela De Lima, Pascal Tribotte
Abstract Partially Premixed Combustion (PPC) of fuels in the gasoline octane range has proven its potential to achieve simultaneous reduction in soot and NOX emissions, combined with high indicated efficiencies; while still retaining proper control over combustion phasing with the injection event, contrary to fully premixed strategies. However, gasoline fuels with high octane number as the commonly available for the public provide a challenge to ensure reliable ignition especially in the low load range, while fuel blends with lower octane numbers present problems for extending the ignition delay in the high load range and avoid the onset of knocking-like combustion. Thus, choosing an appropriate fuel and injection strategy is critical to solve these issues, assuring successful PPC operation in the full engine map.
2016-02-01
Technical Paper
2016-28-0007
R V Manikanta Chari Kancherla, Balamurugan Rathinam, Benoit Douailler, Upendra Naithani, Vincent Dugue, Francois Vaxelaire
Abstract This state of art investigation report explains the limitations of Rosin-Rammler approach in comparison with breakup approach. The injection phenomenon of a commercial injector is simulated at various injection pressures, with Heptane (C7H16) in a spray bomb. It is observed that Breakup approach is better suitable in terms of correlation for spray modelling than the Rosin-Rammler approach when the injection pressures are 10 and 20 MPa, the SMD correlation shows also a good correlation at these pressures. At 4 MPa, correlation is a bit poorer, which is coherent as break-up models are best suited to high injection pressures configurations. Also, in each approach the primary dependent parameters are fine-tuned and their effects are discussed.
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