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Technical Paper
2014-11-11
Ludek Pohorelsky, Pavel Brynych, Jan Macek, Pascal Tribotte, Gaetano De Paola, Cyprien Ternel
The objective of this paper is to present the results of the GT Power calibration with engine test results of the air loop system technology down selection described in the SAE Paper No. 2012-01-0831.Two specific boosting systems were identified as the preferred path forward: (1) Super-turbo with two speed Roots type supercharger, (2) Super-turbo with centrifugal mechanical compressor and CVT transmission both downstream a Fixed Geometry Turbine. The initial performance validation of the boosting hardware in the gas stand and the calibration of the GT Power model developed is described. The calibration leverages data coming from the tests on 2 cylinder 2-stroke 0.73L 45kW diesel engine. The initial flow bench results suggested the need for a revision of the turbo matching due to the big gap in performance between predicted maps and real data. This activity was performed using Honeywell turbocharger solutions spacing from fixed geometry waste gate to variable nozzle turbo (VNT). New simulations results recommend VNT as it offers a higher potential to reduce BSFC with increase power and low end torque output than the original matching.
Technical Paper
2014-04-01
Renaud Deborne, Skárlet Khouri Silva, Andras Kemeny
Abstract By the action on the steering wheel, the driver has the capability to control the trajectory of its vehicle. Nevertheless, the steering wheel has also the role of information provider to the driver. In particular, the torque level at the steering wheel informs the driver about the interaction between the vehicle and the road. This information flow is natural due to the mechanical chain between the road and the steering wheel. Many studies have shown that steering wheel torque feedback is crucial to ensure the control of the vehicle. In the context of uncoupled steering (steer-by-wire vehicle or driving simulators), the torque rendering on the steering wheel is a major challenge. In addition, of the trajectory control, the quality of this torque is a key for the immersion of drivers in virtual environment such as in driving simulators. The torque-rendering loop is composed of different steps. At first, a vehicle dynamics model computes the torque level at the steering wheel regarding the vehicle state (steering wheel position, vehicle speed, etc.).
Article
2014-01-22
Software company rFactor Pro developed software for a major F1 team to overcome the problem of driver-in-the-loop simulator dynamics reaction lag (latency); now it is cascading the solution into production vehicle simulators.
Article
2013-12-10
Currently just an importer, Renault will develop and build vehicles in China under a joint venture with Dongfeng that on Dec. 5 was officially approved by the Chinese federal government. According to a very brief Renault press release on the joint venture, "With the support of both Dongfeng Motor and the Renault-Nissan Alliance, stakeholders of both sides will push forward close cooperation in every sector, notably research and development, purchasing, manufacturing, and marketing."
Article
2013-09-24
Renault unveiled the Initiale Paris concept at Frankfurt, designed as a replacement model for the Renault Espace and also to show Renault’s thinking for future high-end vehicles.
Article
2013-04-18
Leoni AG, a wiring systems supplier, describes competitiveness of aluminum wiring with enhanced corrosion protection of joints. Shows preformed harnesses that simplify assembly line installation. Describes thermal protection systems for these harnesses, and calls them production-ready.
Technical Paper
2013-04-08
Olivier Laget, Cyprien Ternel, Julien Thiriot, Sébastien Charmasson, Pascal Tribotté, Fabrice Vidal
The target of substantial CO₂ reductions in the spirit of the Kyoto Protocol as well as higher engine efficiency requirements has increased research efforts into hybridization of passenger cars. In the frame of this hybridization, there is a real need to develop small Internal Combustion Engines (ICE) with high power density. The two-stroke cycle can be a solution to reach these goals, allowing reductions of engine displacement, size and weight while maintaining good NVH, power and consumption levels. Reducing the number of cylinders, could also help reduce engine cost. Taking advantage of a strong interaction between the design office, 0D system simulations and 3D CFD computations, a specific methodology was set up in order to define a first optimized version of a two-stroke uniflow diesel engine. The main geometrical specifications (displacement, architecture) were chosen at the beginning of the study based on a bibliographic pre-study and the power target in terms. Using 3D CFD, the expansion/scavenging/compression phases were computed in order to evaluate the scavenging characteristic and the in-cylinder aerodynamics level which mainly depend on the combustion chamber geometry and on the intake and the exhaust manifolds and strategies.
Article
2013-02-25
Although German carmakers express concern over R-1234yf safety, others remain nominally committed. But work on AC6 blend (R-445A) continues, and R-744 (carbon dioxide as a refrigerant) is back in the picture. The industry also faces preparation for challenges from new EPA AC17 drive cycle that measures A/C fuel consumption for future CAFE credits.
Technical Paper
2012-06-13
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. Moreover we investigate the influence of the harmonic content of the supply current due to the regulation system, as well as the tangential forces effect on stator teeth.
Technical Paper
2012-04-16
Ashish Vashishtha, Balamurugan Rathinam, Laurent Delahaye, Frederic Ravet, Frederic Justet
In this study, different designs of intake ports for two-stroke Ultra Low Cost Gasoline Direct Injection Engine (ULC-GE) has been analyzed to conclude on best design using steady state analysis in STAR-CD. The four types of intake ports design with two cylinders, each having fourteen ports, have been studied. The basic differences in designs are horizontal inlet entry (perpendicular to cylinder axis) and vertical inlet entry (in-line with cylinder axis) having rotation of flow clockwise and anticlockwise. Each type is further differentiated in eight cases with varying distances between axis of two-cylinder as 85mm, 88mm, 91 mm, 94 mm, 97 mm, 100 mm, 105 mm and 112 mm. These designs are analyzed for four different pressure drops as 10 mbar, 50 mbar, 100 mbar and 150 mbar. The initial study for all four types of intake ports, with 85 mm distance between axis of two-cylinder has been carried out and it is found that at all the port entries, static pressure is almost homogeneously distributed for vertical entry designs as compared to horizontal entry designs.
Technical Paper
2012-04-16
Olivier Grondin, Jonathan Chauvin, Laurent Fontvieille
This paper proposes a method to detect an intake manifold leakage for a Diesel engine with a dual loop EGR system. The intake manifold leak has a strong impact on the engine performances by changing the intake manifold burned gas ratio. This fault is analyzed according to the control structure used and also according to the EGR operating mode. The paper proposes a diagnosis algorithm to detect the intake manifold leak in sequential or simultaneous use of the two EGR paths. The sensors considered are the mass air flow meter, the intake manifold pressure sensor, the exhaust equivalence ratio sensor and the differential pressure sensor (across the HP EGR valve). The diagnosis is based on a criteria that uses the redundancy between these sensors and air system models or estimators. The diagnosis threshold depends on the engine operating conditions as well as the sensor or model dispersions. The proposed algorithms is implemented online using an approximation of the diagnosis threshold computed with Monte Carlo simulations.
Technical Paper
2012-04-16
Ludek Pohorelsky, Pavel Brynych, Jan Macek, Pierre-Yves Vallaude, Jean-Charles Ricaud, Philippe Obernesser, Pascal Tribotté
This paper introduces a research work on the air loop system for a downsized two-stroke two-cylinder diesel engine conducted in framework of the European project dealing with the POWERtrain for Future Light-duty vehicles - POWERFUL. The main objective was to determine requirements on the air management including the engine intake and exhaust system, boosting devices and the EGR system and to select the best possible technical solution. With respect to the power target of 45 kW and scavenging demands of the two-cylinder two-stroke engine with a displacement of 0.73 l, a two-stage boosting architecture was required. Further, to allow engine scavenging at any operation, supercharger had to be integrated in the air loop. Various air loop system layouts and concepts were assessed based on the 1-D steady state simulation at full and part load with respect to the fuel consumption. Among the investigated boosting devices were the positive displacement and centrifugal superchargers driven from the crankshaft and placed upstream or downstream of the turbocharger with either the waste gate or variable turbine.
Technical Paper
2012-04-16
Jesus Benajes, Ricardo Novella, Daniela De Lima, Vincent Dugue, Nicolas Quechon
An innovative alternative to overcome the load limits of the early injection highly premixed combustion concept consists of taking advantage of the intrinsic characteristics of two-stroke engines, since they can attain the full load torque of a four-stroke engine as the addition of two medium load cycles, where the implementation of this combustion concept could be promising. In this frame, the main objective of this investigation focuses on evaluating the potential of the early injection HPC concept using a conventional diesel fuel combined with a two-stroke poppet valves engine architecture for pollutant control, while keeping a competitive engine efficiency. On a first stage, the HPC concept was implemented at low engine load, where the concept is expected to provide the best results, by advancing the start of injection towards the compression stroke and it was confirmed how it is possible to reduce NOX and soot emissions, but increasing HC and CO emissions. Additionally, even operating at low engine loads, combustion starts too early during the compression stroke, advancing the combustion phasing and worsening the engine efficiency.
Article
2011-11-11
Both refrigerants are blends, normally not favored by the automotive industry. But both are likely to cost much less than R-1234yf, the current industry choice for a low-global-warming refrigerant. And one, AC-6, is far less flammable.
Technical Paper
2011-08-30
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.
Technical Paper
2011-06-09
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. Since many of the most important characteristics of the spray development, as the penetration or the axial velocity, can be captured using 2D simulations, in this preliminary validation of ELSA model only two-dimensional simulations have been performed.
Article
2011-06-02
In what it claims is the largest such installation in the automotive industry, Renault will build enough solar roof panels at its France assembly plants to provide a year's worth of electrical power for a town of 15,000 people.
Technical Paper
2011-04-12
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. In particular it allows demonstrating that plastic flow occurs in the substrate and in the overlay during the first combustion cycles and the first thermal cycles.
Technical Paper
2011-04-12
Benoit Douailler, Frederic Ravet, Vivien Delpech, Dominique Soleri, Benjamin Reveille, Rajesh Kumar
CNG is one of the most promising alternate fuels for passenger car applications. CNG is affordable, is available worldwide and has good intrinsic properties including high knock resistance and low carbon content. Usually, CNG engines are developed by integrating CNG injectors in the intake manifold of a baseline gasoline engine, thereby remaining gasoline compliant. However, this does not lead to a bi-fuel engine but instead to a compromised solution for both Gasoline and CNG operation. The aim of the study was to evaluate the potential of a direct injection spark ignition engine derived from a diesel engine core and dedicated to CNG combustion. The main modification was the new design of the cylinder head and the piston crown to optimize the combustion velocity thanks to a high tumble level and good mixing. This work was done through computations. First, a 3D model was developed for the CFD simulation of CNG direct injection. Numerical tests were carried out on the injection test bench configuration in order to achieve good correlations between calculations and experiments.
Technical Paper
2011-04-12
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. Finally, the architecture has reached the target of 70% NOx efficiency on NEDC cycle while respecting the specifications on the penalty associated with NOx purge (fuel consumption, oil change interval and acoustics constraints).
Technical Paper
2011-04-12
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. These pros and cons are quite restrictive in classical LNT or NH₃-SCR architecture.
Article
2011-03-16
A consortium coordinated by Better Place and including Renault, Continental, Ernst & Young, TÜV Rheinland, KEMA, and five leading European institutions announced on March 2 formal approval from the European Commission of an R&D program on battery swapping.
Technical Paper
2010-10-25
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. The main objectives are to identify the complex mechanisms involved in the combustion process and to define the optimal hydrogen ratio for each combustion mode.
Article
2010-10-22
The Townpod concept from Nissan shares its electric-drivetrain architecture with the forthcoming production Leaf and, therefore, has many similarities with Renault’s electric vehicles and concepts shown at the 2010 Paris Motor Show.
Article
2010-10-22
Electric cars were central to the Renault booth at the Paris Show, with the Zoe Preview and DeZir Preview concepts unveiled by Renault CEO Carlos Ghosn.
Article
2010-05-10
Alongside a new version of its Megané convertible, Renault debuted the Wind two-seat roadster at the 2010 Geneva Motor Show. The car signals a new market segment for the French car manufacturer and also features an innovative Webasto roof system that shares much in common with a Ferrari model, according to the car’s product director, Pascal Cohen.
Technical Paper
2010-05-05
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. In the present model, the rate of heat release by combustion for the premixed phase is related to the mean reaction rate of fuel which is evaluated by an approach based on tabulated local reaction rate of fuel and on the determination of the Probability Density Function (PDF) of the mixture fraction (Z), in order to take into consideration the local variations of the fuel-air ratio.
Technical Paper
2010-05-05
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.
Technical Paper
2010-05-05
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. Experiments conducted in our laboratory on a special test rig equipped with a high-precision torquemeter, demonstrate that compressor performances in this area cannot be deduced from adiabatic assumption.
Technical Paper
2010-05-05
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. This paper describes how the CIGAL™ (Concomitant Injection of Gas And Liquid fuels) concept can generate a synergy effect between both fuels, which allows combustion efficiency to be increased significantly on turbocharged SI engines.
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