Valeo Thermal Systems

Port-Saint-Louis-du-Rhône, France

Valeo Thermal Systems

Port-Saint-Louis-du-Rhône, France
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Wang Z.,Ford Motor Company | Zhang Y.,Ford Motor Company | Lenormand C.,Valeo Thermal Systems | Ansari M.,Valeo Thermal Systems | Henner M.,Valeo Thermal Systems
SAE Technical Papers | Year: 2017

Radiator thermal cycle test is a test method to check out the robustness of a radiator. During the test, the radiator is going through transient cycles that include high and low temperature spikes. These spikes could lead to component failure and transient temperature map is the key to predict high thermal strain and failure locations. In this investigation, an accurate and efficient way of building a numerical model to simulate the transient thermal performance of the radiator is introduced. A good correlation with physical test result is observed on temperature values at various locations. Copyright © 2017 SAE International.


Bahrani S.A.,University Paris Diderot | Royon L.,University Paris Diderot | Abou B.,University Paris Diderot | Osipian R.,University Paris Diderot | And 2 more authors.
Journal of Applied Physics | Year: 2017

Phase Change Materials (PCMs) are widely used in thermal energy storage and thermal management systems due to their small volume for a given stored energy and their capability for maintaining nearly constant temperatures. However, their performance is limited by their low thermal conductivity and possible leaks while in the liquid phase. One solution is to imprison the PCM inside a polymer mesh to create a Polymeric Phase Change Material (PPCM). In this work, we have studied the cooling and solidification of five PPCMs with different PCMs and polymer fractions. To understand the heat transfer mechanisms involved, we have carried out micro- and macrorheological measurements in which Brownian motion of tracers embedded in PPCMs has been depicted and viscoelastic moduli have been measured, respectively. Beyond a given polymer concentration, it was shown that the Brownian motion of the tracers is limited by the polymeric chains and that the material exhibits an elastic behavior. This would suggest that heat transfer essentially occurs by conduction, instead of convection. Experiments were conducted to measure temperature variation during cooling of the five samples, and a semi-empirical model based on a phenomenological approach was proposed as a practical tool to choose and size PPCMs. © 2017 Author(s).


Beddadi Y.,Valeo Thermal Systems | Henner M.,Valeo Thermal Systems | Demory B.,Valeo Thermal Systems
11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015 | Year: 2015

Fan systems for automotive applications operate in engine compartment where temperature can reach 120°C. In addition to these severe conditions, the electrical motor that drives the fan is subjected to self heating by several mechanisms of losses such as mechanical friction, joule effect and electromagnetic fields. The higher the temperature is the lower the motor efficiency, and the lower the durability is. The purpose of following study is to develop the concept of virtual prototyping for reliability tests by using a complete representation of the fan system during simulation. To achieve this objective, the context of validation is fully modeled, including the climatic test chamber and the various physical mechanisms that influence the performances. A methodology for aero-thermal simulation, coupled with electro models is investigated: results have been post-processed in terms of temperature distribution and cooling effects of the forced air flowing through the motor. Flow rates and pressure losses are assessed through different locations of the fan system (from inlet to outlet, from the e-motor rear face to the front face, close to the brushes, and so one ...). In order to validate and to check the relevancy of the process, some prototypes have been equipped with thermal sensors and the measurements are compared to the simulation results. These correlations between simulations and experimental results are fairly good, indicating that simulation can be used to improve the fan system cooling (prevent over heating of the motor) as well as the durability of the components (less critical temperature on the components).


Lissner M.,Valeo Thermal Systems | Lissner M.,IRSTEA | Tissot J.,Valeo Thermal Systems | Leducq D.,IRSTEA | And 2 more authors.
Applied Thermal Engineering | Year: 2016

This study focuses on the optimization of a phase change heat accumulator used in engine cooling loop of automotive applications. Heat transfer is mainly limited by the low PCM heat transfer rate, due to a relatively low thermal diffusivity. A significant conductivity enhancement can be achieved by adding fins, but this also leads to decrease the heat storage capacity of the accumulator by reducing the volume available for phase change materials. Thus, geometry characteristics of fins such as pitch, height and thickness play an important role in the performance and storage capacity of the heat accumulator and should be considered carefully. In order to optimize these geometric parameters, a numerical model is developed to simulate various configuration of heat accumulator. The simulation results are presented and used to define a set of optimal solutions based on heat transfer rate and heat storage capacity. The model can be easily applied to similar geometries, materials or applications. Results show that there is an optimal height of fins that provides a satisfying heat transfer rate. On the other hand, pitch and thickness of fins should be the smallest as possible to improve contact points between fins and wall and to improve temperature homogeneity. However, results show that optimal design of fins depends on flow conditions and, several optimal may be defined considering heat accumulator application. © 2016 Elsevier Ltd. All rights reserved.


Lujan J.M.,Polytechnic University of Valencia | Climent H.,Polytechnic University of Valencia | Dolz V.,Polytechnic University of Valencia | Moratal A.,Polytechnic University of Valencia | And 2 more authors.
Applied Thermal Engineering | Year: 2016

In this paper, an experimental facility is implemented with the aim of improving the performance of internal combustion engines working at low ambient temperatures. Pollutant emissions and fuel consumption are one of the major issues that automotive engineers have to face. Cold engine start and warming up analysis have become important topics for researches. In this work, an exhaust heat recovery system for a diesel engine has been proposed as a solution to cold operation negative effects. The energy obtained from the exhaust gases was used to increase the intake air temperature. The experiments were carried out in transient load conditions at three different levels of ambient temperature (up to -7. °C). Exhaust heat recovery was combined with different strategies of exhaust gas recirculation. Intake air heating results with the heat recovery system show a reduction of 65% in unburned hydrocarbons, 40% in carbon monoxide and 10% in fuel use compared to standard air-air intercooler. © 2016 Elsevier Ltd.


Saab S.,Valeo Thermal Systems | Hetet J.-F.,École Centrale Nantes | Maiboom A.,École Centrale Nantes | Charbonnelle F.,Valeo Thermal Systems
SAE Technical Papers | Year: 2013

The tightening restrictions, in terms of fuel consumption, have pushed the vehicle manufacturers and equipment suppliers into searching for innovative ways to reduce the carbon dioxide emissions. Along with the ameliorations added to the engine itself, additional systems are grafted to the engine in order to keep up with the ever-changing laws. Isolating the impact on the fuel consumption of an added system, by on board testing, is a complicated task. In this case, using simulation modeling allows the reduction of delays related to prototyping and testing. This paper presents modeling of various thermal systems in a vehicle and their interactions to evaluate the fuel consumption using AMESim software. As means to reduce the CPU cost of the model (calculation time), without decreasing its predictability, engine modeling has been done by two steps: high frequency model and mean value model. While the first model is used to characterize the engine indicated work, exhaust losses and thermal losses, the second model is integrated in a complete vehicle model where the additional thermal systems are connected. From these additional systems, the model contains: the cooling system, lubricating system, EGR (Exhaust Gas Recirculation) and charged air cooling system. Using this model helps evaluating the cost of each system in terms of fuel consumption. Comparing different cooling systems architectures is possible. Furthermore, the impact of air shutters on both the aerodynamics and the thermal stability of the engine is studied. Copyright © 2013 SAE International.


Saab S.,Valeo Thermal Systems | Hetet J.-F.,École Centrale Nantes | Maiboom A.,École Centrale Nantes | Charbonnelle F.,Valeo Thermal Systems
SAE Technical Papers | Year: 2013

The impact of the drag coefficient of a vehicle on its fuel consumption is very important. This paper will treat a proposition to reduce the drag coefficient via a reduction of the underhood opening area. The coastdown technique is adopted to find the drag coefficient. Three post-processing methods are then compared. Although, reducing the underhood opening ameliorates the drag coefficient, it influences as well the thermal performance of the cooling system, causing a possible overheating of the engine. For this reason, the impact of the underhood opening area on the cooling air speed is studied in detail as well. The purpose of these tests is to draw some variation laws that govern the response of a vehicle to a reduction in the underhood opening. Copyright © 2013 SAE International.


Pasquet L.,Valeo Thermal Systems | Berges D.,Valeo Thermal Systems | Da Silva P.,Valeo Thermal Systems | Demarcq C.,Valeo Thermal Systems
SAE Technical Papers | Year: 2013

To assess the ability of a material to create filler metal flow and fill the brazing joint areas during the brazing process, we adapted a method which is called aluminum Flow Factor test. The target is to take benefit of this test in order to reach an optimum level of heat exchanger performance from project development steps. This paper studies similar aluminum clad material compositions coming from different suppliers. After brazing process, significant differences were noticed in the filler metal flow results. This study highlighted the impact of brazing peak temperature to create more or less flow of filler metal. The Flow Factor is promoted by the increase of brazing peak temperature. It also showed that regardless the material gage, at a low peak temperature of 591°C, Flow Factor are quite similar around 0,18. Even if the silicon particle size was not especially studied, compared to others papers, this study didn't show a main impact on Flow Factor results compared to other factors. Copyright © 2013 SAE International.


Saab S.,Valeo Thermal Systems | Charbonnelle F.,Valeo Thermal Systems | Hetet J.-F.,École Centrale Nantes | Maiboom A.,École Centrale Nantes
Proceedings of the 26th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2013 | Year: 2013

The international laws aim more and more to reduce the carbon dioxide emissions, especially in the ground transportation field. To keep up with these constantly restraining regulations, the automotive industry searches to better understand the impact of each subsystem in the vehicle on the global fuel consumption. Nevertheless, until now, almost no studies have been done on the impact of the cooling system performances and its design on the fuel consumption of an internal combustion engine. This paper aims to present a new approach for a complete vehicle modeling while taking into consideration the major interactions between the cooling system and its surroundings. Thus, along with the engine and the cooling system, the air admission system (charged air cooler and exhaust gas recirculation cooler), the lubricating system, the thermal inertias and the electric components are modeled. In order to have highly predictive and accurate results while keeping a reasonable calculation time, the engine model used is developed in two steps: starting with a high frequency engine model, various operating points are calculated. Then, using these results, a mean value engine model (MVEM) is built. This second model uses the concept of efficiencies maps to find the operating point, heat dissipation and fuel consumption. The results given by the model are compared to tests done on a vehicle with a similar engine displacement. The comparison is even made in transient motion. Such model will help comparing, energy wise, different cooling system architectures for a traditional vehicle. The next step will be using this model for hybrid electric vehicles and study the possibilities of energy recuperation for the cabin thermal management.


Benouali J.,Climate Control, Inc. | Petitjean C.,Valeo Thermal Systems | Citti I.,Valeo Thermal Systems | Beauvis R.,Valeo Thermal Systems | Delaforge L.,Valeo Thermal Systems
SAE Technical Papers | Year: 2014

The development of Electrical and Hybrid cars led to the introduction of reversible heat pump systems in order to reduce the energy consumption and increase the car autonomy during the Zero Emission Mode. One of the most important components in the heat pump system, is the evaporator condenser that "pumps the heat" from the ambient air. Moreover, this heat exchanger has to work in both modes: A/C (condenser mode) and heat pump (evaporator mode). This paper will explain the main steps of the development of this heat exchanger: circuiting (refrigerant side) in order to improve the homogeneity and the performancesfins (air side) in order to reduce icing impact. We will also present system tests results that illustrate the impact of those evolutions on loop performances (heating capacity and COP). Copyright © 2014 SAE International.

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