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Inter-Laboratory Characterization of Biot Parameters of Poro-Elsastic Materials for Automotive Applications

Renault-Philippe Mordillat
Autoneum Holding AG-Francesca Ronzio, Claudio Bertolini
  • Technical Paper
  • 2020-01-1523
To be published on 2020-06-03 by SAE International in United States
Automotive suppliers provide multi-layer trims mainly made of porous materials. They have a real expertise on the characterization and the modeling of poro-elastic materials. A dozen parameters are used to characterize the acoustical and elastical behavior of such materials. The recent vibro-acoustic simulation tools enable to take into account this type of material but require the Biot parameters as input. Several characterization methods exist and the question of reproducibility and confidence in the parameters arises. A Round Robin test was conducted on three poro-elastic material with four laboratories. Compared to other Round Robin test on the characterization of acoustical and elastical parameters of porous material, this one is more specific since the four laboratories are familiar with automotive applications. Methods and results are compared and discussed in this work. Finally some guidelines are drawn to improve the confidence in the characterized parameters and to compare them under similar conditions possibly adapted to the final application.
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Optimal Yaw Rate Control for Over-Actuated Vehicles

Renault-Xavier Mouton, Didier Martinez
ENSTA Paris-Moad Kissai, Bruno Monsuez, Adriana Tapus
  • Technical Paper
  • 2020-01-1002
To be published on 2020-04-14 by SAE International in United States
As we are heading towards autonomous vehicles, additional driver assistance systems are being added. The vehicle motion is automated step by step to ensure passengers’ safety and comfort, while still preserving vehicle performance. However, simultaneous activations of concurrent systems may conflict, and non-suitable behavior may emerge. Our research work consists in proving that with the right coordination approach, simultaneous operation of different systems improve the vehicle’s performance and avoid the emergence of unwanted conflicts. To prove this, we gathered different control architectures implemented in commercial passenger cars, and we compared them with our control architecture using a unified reference vehicle model. The high-fidelity vehicle model is developed in Simcenter Amesim in a modular and extensible manner. This enables adding systems in a plug-and-play way. Not only different control architectures can be tested on the same vehicle, but also different systems combinations can be evaluated. In this research, the vehicle can steer at the front and at the rear, and each wheel can be braked independently. Each of the actuators concerned can influence the vehicle’s yaw…
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Evaluation of flow paths due to leakages of flammable liquids by the SPH method. Application to real engines.

Renault-Frederic Ravet
AVL France-Simon Ameye
  • Technical Paper
  • 2020-01-1111
To be published on 2020-04-14 by SAE International in United States
One the most important safety issues for automotive engineering is to avoid any fire due to the ignition of flammable liquids, which may result from leaks. Fire risk is a combination of hot temperature, fast vaporization and accumulation of vapor in a cavity. In IC engines, potentially flammable liquids are fuel and oil. To guarantee safety, no flammable liquids must come into contact hot parts of the engine. Consequently, shields are designed to guide the flow path of possible leakages and to take any flammable liquid out of the hot areas. Simulation is a great help to optimize the shape of the shield by investigating a large number of possible leakages rapidly. Recent breakthroughs in numerical methods make it possible to apply simulations to industrial design concepts. The approach is based on the Lagrangian Smoothed Particle Hydrodynamics (SPH) method. The SPH method is an efficient method to capture the rivulets on highly complex geometries and thus determine the relevance of the design. A new implicit algorithm was developed to make the simulations faster. Preliminary tests…
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Optimal Control of Mass-transport Time-delay Model in a Low-pressure EGR

Renault-Sandra Malik Hamze
GIPSA-lab-Emmanuel Witrant
  • Technical Paper
  • 2020-01-0251
To be published on 2020-04-14 by SAE International in United States
This paper presents the control-oriented model and control design of the burned gas ratio(BGR) transport phenomenon, witnessed in the intake path of an internal combustion engine, due to the redirection of burned gases to the intake path by the low-pressure EGR. Based on a nonlinear AMESim model of the engine, the BGR in the intake manifold is modeled as a state-space output time-delay model, or alternatively as an ODE-PDE coupled system, that take into account the time delay between the moment at which the combusted gases leave the exhaust manifold and that at which they are readmitted in the intake manifold. In addition to their mass transport delay, the BGRs in the intake path are also subject to inequality constraints because they are positive percentages lying between 0 and 100. The objective of the control problem is to track a reference output profile of the BGR in the intake manifold, taking into account the transport delay and the state(output) and input constraints of the system. In this aim, two indirect optimal control approaches are implemented…
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Calculation Process with Lattice Boltzmann and Finite Element Methods to Choose the Best Exterior Design for Wind Noise

Renault-Guillaume Baudet, Cecile Dutrion, Remi Lorenzi, Felix Gendre, Shanshan Geng
Published 2019-06-05 by SAE International in United States
Wind noise in automobile is becoming more and more important as the customer expectations increase. On the other hand, great progress has been made on engine and road noises, especially for electric and hybrid vehicles. Thus, the wind noise is now by far the major acoustic source during road and motorway driving.As for other noises, automobile manufacturers must be able, for a new car project, to specify, calculate and measure each step of the acoustic cascading:SourceTransfers, both solid and air borneIn the case of the automotive wind noise, the excitation source is the dynamic pressure on the vehicle’s panels. This part of the cascading is the one influenced by the exterior design. Even if many others components (panels, seals, cabin trims) have a big influence, the exterior design is a major issue for the wind noise. The wind noise level in the cabin may change significantly with only a small modification of the exterior design.This paper addresses the problem of doing the good choice of exterior design in the early phases of a new vehicle’…
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Influence of the Micro- and Macro-Structural Parameters on the Dynamic Behavior of Structures Made of Polymers Reinforced with Short Glass Fibers

Renault-Mehdi Zerrad, Benjamin Eller
INSA-Lyon / LVA-Nicolas Totaro
Published 2018-06-13 by SAE International in United States
In order to design vehicles with diminished gCO2/km emissions level, car manufacturers aim at reducing the weight of their vehicles. One of the solutions advocated by the automotive industry consists in the replacement of metallic parts by lighter systems made of polymer reinforced composites. Unfortunately, the numerical simulations set to evaluate the vibratory and acoustic performances of systems made of this kind of materials are often not sufficiently effective and robust so that convincing test/simulation correlations are rarely met. Indeed, for polymer-based materials, numerous parameters affect the vibroacoustic behavior. On the one hand, it is well known that the viscoelastic properties (Storage -Young- and dissipative moduli) of polymers depend on the temperature, loading frequency and sometimes the humidity content. On the other hand, when focusing of short-fiber composites, the injection molding process leads to an inhomogeneous spatial distribution (density and orientation) of the reinforcing fibers. For instance, through-thickness heterogeneity (orientation and volume fraction) is largely reported. More precisely, near the mid-surface, the volume fraction of fibers is increased and they are mostly oriented perpendicularly to…
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Simulation Strategy for Structure Borne Noise Sources: Use of Super Elements and Blocked Forces Tensors between Suppliers and OEMs to Validate Components at Early Design Stage

Renault-Céline ROUSSET, Guillaume Baudet
Valeo Systemes Thermiques-Laurent Legot
Published 2018-06-13 by SAE International in United States
This paper is a case study from the TESSA project (French funded research program “Transfert des Efforts des Sources Solidiennes Actives”). The general frame of the work was to assess a collaborative design process between a car manufacturer and a major supplier using FE modelling and condensation of structure borne noise sources as an alternative to classic specification method for structure borne sources.Super elements from different FE commercial softwares have been used to assess the reliability of the method, the compatibility of the softwares and, most important, the relevance of applying a blocked force tensor to the component super element to predict the interior contribution of a component which is the originality of this work.The case study is an internal combustion engine cooling module (fan + shroud + exchangers) from VALEO including all assembly details (clips, decoupling elements) modelled under ABAQUS and its integration in a RENAULT Espace under NASTRAN. The force tensor is the rotating forces generated by the fan unbalance and propagating through the sub-component of the cooling pack to the car-body. The…
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Robust Design of Acoustic Treatments for Powertrain Noise Radiation

Renault-Philippe Mordillat, Cécile Dutrion
Free Field Technologies-Barthélémy Petit, Eveline Rosseel, Benoit Van den Nieuwenhof
Published 2018-06-13 by SAE International in United States
The reduction of the emitted noise from vehicles is a primary issue for automotive OEM’s due to the constant evolution of the noise regulations. As the noise generated by the powertrain remains one of the major noise sources at low/mid vehicle velocities, focus is set on efficient methods to control this source. Acoustic treatments and covers, made of multi-layered trimmed panels, are frequently selected to control the radiated sound and its directivity. In this context, numerical acoustic simulation is an attractive approach as efficient methodologies are available to study the acoustic radiation of powertrain units in working conditions (up to 6500 RPM nd frequencies up to 4 kHz). Moreover, handling acoustically-treated covers in such simulations has a low impact on the computational cost. Nevertheless, the robust design of treatments (optimization and variability analysis) is more challenging as it implies multiple acoustic radiation analyses, leading to impracticable computational times in industrial conditions. This paper presents a framework for the efficient solution of acoustic radiation models where only a localized part of the model is subjected to design…
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Analysis of Systematic Calibration of Heat Transfer Models on a Turbocharged GDI Engine Operating Map

Renault-Simon Le Guen, Sabre Bougrine
Ecole Centrale De Nantes-Alain Maiboom, Xavier Tauzia
Published 2018-04-03 by SAE International in United States
In order to simulate the working process, an accurate description of heat transfer occurring between in-cylinder gases and combustion chamber walls is required, especially regarding thermal efficiency, combustion and emissions, or cooling strategies.Combustion chamber wall heat transfer models are dominated by zero-dimensional semi-empirical models due to their good compromise between accuracy, complexity and computational efficiency. Classic models such as those from Woschni, Annand or Hohenberg are still widely used, despite having been developed on rather ancient engines. While numerous authors have worked on this topic in the past decades, little information can be found concerning the systematic calibration process of heat transfer models.In this paper, a systematic calibration method based on experimental data processing is tested on the complete operating map of a turbocharged GDI engine. This method mainly relies on heat release rate calculations using in-cylinder pressure during the compression stroke or/and after the end of the combustion. Practical sub-models have been chosen for wall temperatures, trapped mass and residual gas fractions estimations. The described method is tested by calibrating two simple wall heat…
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Experimental and Numerical Analysis of Diluted Combustion in a Direct Injection CNG Engine Featuring Post- Euro-VI Fuel Consumption Targets

Renault-Frederic Ravet, Panagiotis Christou
IFP Energies Nouvelles-Betrand Lecointe, Loic Rouleau
Published 2018-04-03 by SAE International in United States
The present paper is concerned with part of the work performed by Renault, IFPEN and Politecnico di Torino within a research project founded by the European Commission. The project has been focused on the development of a dedicated CNG engine featuring a 25% decrease in fuel consumption with respect to an equivalent Diesel engine with the same performance targets. To that end, different technologies were implemented and optimized in the engine, namely, direct injection, variable valve timing, LP EGR with advanced turbocharging, and diluted combustion. With specific reference to diluted combustion, it is rather well established for gasoline engines whereas it still poses several critical issues for CNG ones, mainly due to the lower exhaust temperatures. Moreover, dilution is accompanied by a decrease in the laminar burning speed of the unburned mixture and this generally leads to a detriment in combustion efficiency and stability. The optimization of in-cylinder turbulence plays a fundamental role in compensating this trend.The present paper is specifically focused on the characterization of the diluted combustion in the direct injection engine. The…
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