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In order to further reduce NOx emissions in increasing HP EGR cooler performance, several OEMs have decided to use a secondary cooling loop dedicated to bring cold water (around 35°C) to the HP EGR heat exchanger. Nevertheless, strongly cooled EGR gases can condensate in the cooler-producing acidic liquids which can corrode some parts in the loop. It is therefore necessary to define EGR components compatible with such kind of environment and constraints. Testing was performed on a 2.0-liter EU4 diesel engine, using a large panel of current fuels including neat biodiesels from soybean, rapeseed or palm, as well as low and high sulfur petroleum-based diesels. In order to cover all existing cycle conditions, the HP EGR is cooled from 20°C to 90°C independently from the engine coolant circuit.

Testing was performed on a 2.0 liter diesel engine with high pressure (HP) and low pressure (LP) EGR, using standard European low sulfur diesel as well as fatty acid methyl ester (FAME) biodiesel fuels produced from soy, rapeseed and palm feedstock, both neat and blended with 50% standard diesel. In the HP EGR configuration, fuel injection, air flow and EGR rate were adapted to achieve the same engine load and NOx emissions for all fuels at the selected test points. Higher brake specific fuel consumption and lower smoke emissions were observed for the biodiesels compared to the standard diesel. In the LP EGR configuration, large reductions in NOx and smoke were observed for all fuels compared to HP EGR. In addition, water condensed in the charge air cooler at coolant temperatures below 30°C. This condensate was collected and analyzed, finding similar volumes and acidity for condensates from all the diesel and biodiesel fuels.

Cooled exhaust gas recirculation is emerging as a promising technology to address the increasing demand for fuel economy without compromising performance in turbocharged spark injection engines. There are a number of different possible architectures, each with its specific characteristics. The objectives of this study are to quantify the increase in knock resistance and to decrease the enrichment at full load in order to target stoichiometric operation over the full operating range, and to define a vehicle compatible cooling system to meet the demanding heat rejection requirements. Based on our knowledge in EGR and air loops, the benefits and risks of various cooled EGR turbocharged systems were evaluated and compared in a preliminary phase. Two architectures, one with high pressure EGR and the other with low pressure EGR, were selected and tested on a 2L turbocharged gasoline engine on a stationary test bench and the performance was compared to the serial production engine.

The current market uses Nylon66 or PA66 based compounds for radiator end tank applications. This study will focus on investigating the feasibility of using Polypropylene based compound material for radiator tank application. Interest in Polypropylene (PP) exists due to various material property advantages as well as cost and weight reduction opportunities. Study will involve 3 different grades of Polypropylene (PP). The Finite Element (FE) simulations and corresponding product testing will investigate the feasibility range for such compounds in radiator tank applications. Validated Finite Element (FE) model will be used to compute the Stress, Strain and Deflection magnitudes in the radiator using specific grade of Polypropylene. Various iterations will be computed to fully understand the effect of temperature on specific grades and its impact on the feasible application range.

Water-cooled charge air cooling is being considered as part of various technology solutions in response to 2007 US, 2010 US, EU4 and EU5 emissions standards. As manufacturers determine appropriate engine and vehicle solutions to meet the upcoming emissions standards, charge air cooling requirements are increasing due to higher turbocharger outlet temperatures and pressures, higher EGR rates, and requests for intake manifold temperature control to manage combustion and exhaust temperatures. Valeo and EMP have collaborated on the development and testing of a water cooled charge air cooler (WCCAC), controlled by a 12 volt brushless motor coolant pump. The system design addresses material temperature limitations of air-air aluminum CAC's and has the potential to simplify the packaging of the air induction system.

This study describes the influence of fan system electric power on the heat performance of engine cooling module versus vehicle speeds, from idle to maximum speed. Depending on the fan system electric power from 60 to 800 watts, for example, and even if the fan is switched on, their behaviors are different versus vehicle speeds. The 70 watts fan has its influence on the heat performance of engine cooling module until medium vehicle speeds but the high electric fan system power has its influence up to maximum speed. This study will focus on this phenomena, particularly, the difference between fan on and off is function of vehicle speeds. A simple simulation model [1] and [2] will be used to explain this phenomena. Also presented in this paper is the heat performance of cooling radiator and cooling module on the several vehicles tested in the climatic wind tunnel according to the cooling specifications.

This study is the continuation of our study published in reference 1 concerning the cooling radiator performance on the vehicle. In addition to the last paper, two main parameters will be shown: the air velocity through the A/C condenser and its heat performance. They will be studied and presented, particularly,: The influence of the cooling radiator (geometry and performance), The influence of size and position of A/C condenser to the cooling radiator, The influence of the electric fan (size, power and performance, fan on or fan off), The influence of fan shroud (without fan shroud, with full fan shroud or with partial fan shroud), The influence of vehicle (pressure coefficient, grill, size of air inlet, under-hood, size of under-hood air outlet, etc).

The previous study presented during the last VTMS 4 showed the following results, for all engine cooling system and depending on the vehicles: Cost reduction by - 10 to -15%, Weight reduction by -15 to - 21%, Coolant volume reduction by -25% Fuel consumption by -3%, Thermal comfort improvement. Despite of these good results, most of car manufacturers hesitated to use this new concept due to this technological breakthrough of engine cooling system because of expensive durability studies. In this paper the electric fan has been simply suppressed and replaced by the heating blower allowing to cool the engine at idle and at low vehicle speed. By suppressing the electric cooling fan, the advantages of this new economical engine cooling system become: cost reduction up to - 30%, weight reduction up to - 30%.

Today the worldwide convergence towards stricter fuel consumption and emission regulations is pushing carmakers and suppliers into new fields of innovation. Valeo Engine Cooling, VEC, is contributing towards these goals by applying its thermal management system expertise in order to reduce fuel consumption and emissions by using an advanced engine cooling system that incorporated variable speed PWM fans, an electric water pump and an electric water control valve. The paper discusses the benefits in terms of engine cooling, fuel economy and emissions over the FTP drive cycle. The paper gives some examples of advanced engine cooling strategies based on a virtual, predictive metal temperature sensor that is used to actuate the electrical water pump at the desired flow rate. The electrical balance between the 42V pump and fans has also been optimized to reduce the vehicle electrical power consumption and to keep the coolant temperature close to 110°C.

The main objectives of new technologies for internal-combustion engine are lower consumption, pollutant reduction and comfort passenger increase. To reach these objectives, we have adopted for engine thermal management two strategies: quicker rise temperature during the cold start and higher engine temperature for part load. To satisfy these criteria, we have modified the classic cooling loop. An electric water pump, an electric water valve and variable speed fan system are the new actuators automatically controlled by electronic calculator. This concept allows to obtain a warm-up time reduced by 50% and 2 to 3% fuel economy on the European cycle.

The exhaust heat exchange coefficient in a pipe of internal combustion engine has been measured with a specific exhaust-air heat exchanger. It''s installed on the exhaust line of IC engine. The Nusselt-Reyonlds correlation has been developed and compared to the steady-state conditions known as Colburn''s correlation. The Convective Augmentation Factor (CAF) is approximately 2 at low Reynolds number and 1 at high Reynolds number. The technology of EGR cooler and the exhaust-coolant heat exchanger for improving the thermal comfort have been shown. A vehicle equipped with a direct-injection turbo diesel engine has been tested in the climatic wind tunnel. The heat performance in the passenger compartment will be presented.

Euro4 and EPA/02 emission regulations for the European and North American Heavy Duty truck market will require development of high efficiency, low pollution diesel engines. Informations received from main engine, truck manufacturers and literature surveys performed during the past two years shows that several technical solutions are being evaluated in order to reach the required emission levels. These technical solutions can be divided into 3 main groups: 1 Further optimization of fuel combustion including: increase of air to fuel ratio, further retardation of fuel injection timing. 2 Cooled EGR including: high recycled exhaust gas ratios, short EGR loop, compressed and aftercooled EGR. 3 Exhaust gas aftertreatment including: de-NOx catalysts, particle traps, particle afterburning. Different technical solutions will have different impacts on the heat rejection requirements and consequently on the layout and costs of the future cooling systems.

The objective of this paper is to present a methodology for the cooling system optimization based on experimental and numerical studies. Experimental measurements of fan performance for several truck fans have been carried out in order to determine the representative fan curves. These fan curves have been used to numerically simulate the performance of a truck cooling module consisting of heat exchangers and fan. The cooling module performance optimization has been carried out considering different fans, fan pumping power and fan overdrive ratios. The fan shroud has great influence on the cooling air flow distribution across the exchangers. The test bench has potentials to test a charge air cooler and a radiator at the same time simulating different truck operating conditions. In order to investigate the influence of different shrouds on the performance, experimental measurements and numerical study have been done for several module configurations.

A simulation approach is developed to define the control strategies of a new ‘intelligent’ component of the engine cooling system: the variable speed fan system. The paper describes the way each component of the cooling loop is characterized by geometric data or test results to create a one dimensional network of the cooling circuit. Then, comparison with experimental confirms the relevance of the models and their limits. At last, several types of control strategies are evaluated on a simplified driving cycle. This study finally determines the necessary tests to obtain a correct model, able to adapt control strategies for any vehicle.

For Valeo Engine Cooling, CFD now plays a key role as a design tool in the optimization of its fans as shown in [13] [6]. The next challenge has been to address installation effects found in the engine block compartment on the fan performances. A first step towards this goal has been to consider the interaction of the fan with the struts or the stators of its support. The potential gains of a stage configuration are first addressed by a dimensional analysis and a simplified radial equilibrium approach. The first CFD results achieved during the optimization of the rotor-stator system implemented on the new fan range are then presented. These are two-dimensional and three-dimensional Navier-Stokes predictions of steady state rotor-stator interaction with or without pitch change. Parametric studies on the stator stagger angle and shape have been performed.

Cutting down fan system development costs, improving quality, and increasing fan efficiency is a challenge that is now being addressed by the engine cooling engineers. In order to attain such a compelling goal, a Virtual Prototyping approach has been adopted, mainly based on Computational Fluid Dynamics (CFD)[7]. For the development of the fans used in the engine cooling systems, CFD now plays a key role as a design tool as well as an optimization tool. Until recently, both complex geometries and low-speed aerodynamics inherent to latter systems have prevented numerical simulations to be part of the design or reblading processes. Since the advent of general purpose CFD softwares capable of adressing the issues pertinent to the engine cooling system fans, a CFD based development of a new standard fan range was initiated. This paper presents the CFD strategy adopted and the results obtained on the new fans.

This paper describes a PC based computer program, NSYSDES (new system design), that will rate a vehicle cooling module including up to five fluid to air components, a fan with shroud and vehicle ram air. It is intended for use by sales and applications engineers who need quick yet reliable ratings of proposed systems to respond to a sales quotation. Given complete package and component geometry specifications, component dimensionless surface friction and heat transfer characteristics and inlet conditions, this program will yield outlet temperatures and system air side pressure drop as primary results. Stressed are user entries and program options rather than in-depth technical descriptions.

This paper is an introduction to the basic concepts of failure induced by thermal expansion in materials of construction for Charge Air Coolers. Presented here are some of the design considerations and validation techniques employed to deal with this problem on a broad application basis.