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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.

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.

A high efficiency lightweight heat exchanger has been developed for water jacket cooling of engine oil in heavy commercial vehicles. This heat exchanger is comprised of aluminum construction, and utilizes recent developments in heat exchanger technology to obtain high heat rejection, low parasitic loss, and superior strength. This new development offers significant advantages over today's stainless steel oil cooler technology. Specifically, a 15-20% increase in performance is typical, while a minimum of 50% weight savings is expected. This innovation has been released for high volume production, and represents a major benefit for our customers.