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In order to accurately predict the performance of a cooling module in an underhood environment, it is essential that the heat fluxes to the air from the various heat exchangers, such as radiator, condenser and charge air cooler, are modeled properly. Simulation models should therefore involve the prediction of the flow and temperature fields in both air and liquid side of heat exchangers. At Behr GmbH & Co., different simulation tools are successfully integrated in the development process to meet this goal. For underhood flow simulations, heat exchanger analysis programs are coupled directly with the flow solver. In order to verify the simulation a validation program has been set up based on the fact, that the air mass flow rate through the cooling module has a major influence on the performance of the radiator. Therefore, calculated air mass flow rates through the radiator were compared with the experimentally measured flow rates.

Engine independent AC-systems, or parking cooling systems for non-idling air conditioning are getting more and more important, because extremely uncomfortable conditions during breaks or a disproportionate amount of fuel consumption for engine idling during breaks are not longer accepted. For cost, weight and package reasons today only thermal storage systems are ready for series production of in series production. The benefits (comfort and fuel savings) and test results of such a system are shown. Future developments of fuel cells or new alternator/battery-systems will probably change this evaluation.

Laser welding is a joining process, which is comparatively new to industrial production and especially to heat exchanger manufacturing. Due to the high energy density of the laser beam, the process is characterized by faster welding speeds with deep penetration as compared to the conventional welding processes. Therefore laser welding technology is widely used in the automotive industry on a variety of different applications. This paper describes the application of laser welding as possible joining technology for exhaust gas heat exchangers made of stainless steel. The cooled exhaust gas recirculation (EGR) technology shows good potential for meeting the actual and future emission targets of diesel engines combined with acceptable fuel consumption. It will be shown that the selection of the base metal and the joining technology are extremely important for the durability of the product because of the severe operating environment the EGR cooler must endure.

Diesel engines of the “new generation” with direct fuel injection are known for their high mechanical efficiency. However, this growth in efficiency does coincide in a decrease of the available amount of heat in the coolant. At low ambient temperatures the heat dissipated by the engine is no longer sufficient to ensure a quick defrosting of the windshield and a comfortable temperature level inside the passenger compartment. Besides the familiar auxiliary heating systems such as aux. fuel heaters or the PTC heaters this problem can be solved by the use of a Visco® heater. This following article will describe the function of the Visco® heater, its integration into the vehicle as well as its effects on vehicle heat up and fuel consumption.

Aluminum has a number of features which make it superior to the other non-ferrous metals (copper and brass) normally used for radiators in the past. Apart from the low specific weight, there are additional advantages, such as outstanding heat conductivity, strength, corrosion resistance and convenient forming and processing qualities. Brazed aluminum radiators with flat tubes and louvered serpentine fins are used for high horsepower engines and/or in confined spaces, while mechanically assembled round tube or oval tube radiators are preferred for smaller engines and/or where there is sufficient space. The excellent field results with car radiators have led to the use of aluminum radiators in trucks as well. More than 10 million fluxless brazed flat tube radiators with serpentine fins have been manufactured by Behr since 1975. Serial production for trucks was started in 1988.

The Aluminum radiator has a number of features that make it very attractive for vehicle applications in general. Superior durability and reliability in conjunction with its excellent specific values for costs, performance and weight warrant a favorable solution for Heavy Duty Trucks. Behr has been supplying Aluminum radiators for trucks in Europe for over 10 years and in North America for 4 years. This paper examines the results based on this long-term experience. It reviews the field experience compared to Copper/Brass radiators, examines design and mounting features as well as the manufacturing processes. Durability, external and internal corrosion resistance are emphasized as essential characteristics. A special focus is the thermodynamics of Aluminum radiators. The paper reviews methods to simulate the thermodynamic behavior of radiators and the progress in the specific performance, based on the development of improved radiator core matrices.