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In this paper we discuss a method for determining heat transfer behaviour during tests in aerodynamic wind tunnels. The method involves computing the heat power evacuated by the heat exchanger as a function of the cooling airflow drag. Using dimensional analysis techniques, we define a Thermal Efficiency Coefficient (TEC). Systematic tests on three geometrically different types of vehicles show that there is a universal law governing the variation in TEC with cooling airflow drag. By associating the curve for this universal law with the characteristic curve for the heat exchanger alone, we can compute a TEC value for a measured cooling airflow drag value, and thus determine the vehicle's engine cooling performance during aerodynamic tests.

The structural design of current vehicle front units has to account for an increasing number of constraints: improvement of real-world performance in safety for occupants and others road users, perform in the various ratings and meet future regulations. Therefore the structural car design is the result of a compromise between pedestrian protection, car-to-car compatibility and self- protection. In addition to these safety considerations, reparability constraints are becoming more and more demanding and intrusive toward the other safety requirements. The need to reduce emissions through fuel consumption control requires a reduction of the overall body weight which leads usually to more difficulties to achieve a correct structural behavior. Some of these constraints lead to solutions which are in opposition and in general to unsatisfactory compromises. It is suggested to develop a more comprehensive approach in order to better take into account both safety requirements and reparability.

Accident studies conducted during the last twenty-five years clearly show that car to car head-on collision is a major impact configuration to take into account in order to improve safety on the roads. With new self protection ratings all cars offer equivalent behaviour against a fixed obstacle. So, in the future, the main progress will have to be made in car to car compatibility. Recent studies have shown the feasibility of designing compatible cars for both structure behaviour and occupant protection. However, some requirements on front unit design could make this aim more difficult to achieve. We suggest developping a more comprehensive approach in order to better take into account all the constraints.

Previous studies of in-cylinder heat transfers give numerous approaches of heat losses modelling principally compression and expansion strokes. These simulation methods are discussed showing that their accuracy during the intake stroke is neglected. Since most of the modern engines use strong structured air motion during the intake and compression strokes to both reduce consumption and reach different emissions levels targets, one may focus on in-cylinder aerodynamics and convective heat transfer coupling. The experimental velocity data acquired allow us to get an in-depth understanding of the spatial and temporal gradients of measured heat transfers in the cylinder of an internal combustion engine. Two different experimental methods have been used to investigate the in-cylinder air motion. First, near wall flow has been studied using two component local time-resolved Laser Doppler Anemometry (LDA).

In a consortium of European industrial partners and research institutes, a combination of industrial development and scientific research was organised. The objective was to improve the catalytic NOx conversion for lean burn cars and heavy-duty trucks, taking into account boundary conditions for the fuel consumption. The project lasted for three years. During this period parallel research was conducted in research areas ranging from basic research based on a theoretical approach to full scale emission system development. NOx storage catalysts became a central part of the project. Catalysts were evaluated with respect to resistance towards sulphur poisoning. It was concluded that very low sulphur fuel is a necessity for efficient use of NOx trap technology. Additionally, attempts were made to develop methods for reactivating poisoned catalysts. Methods for short distance mixing were developed for the addition of reducing agent.

Increasing design emphasis on factors such as styling, fuel reduction and soundproofing raises a number of additional problems concerning under-bonnet aerodynamics and heat exchange. Because experimental work on successive prototypes entails heavy penalties in terms of development lead-time, it is becoming more and more important to integrate simulation from the pilot study stage, as a way to minimize the number of prototypes. Fortunately, early integration of under-bonnet air-flow modelling is becoming an increasingly viable proposition, thanks to the spectacular increase in computer processing power, which stimulates the development of more efficient meshing software and facilitates the generalized implementation of CAD techniques throughout the design processes. Modelling thus emerges as a new investigatory method that enhances the design office's capabilities by enabling it to adopt a sharper design focus right from the pilot project stage.

Accident studies show that incompatibility has become the main cause of fatal injury in car-to-car accidents. There is a general agreement today that improving compatibility is one of the most effective ways to reduce the number of road accident victims. Therefore, structural car design must take into account other road users without decreasing self-protection level supplied by all new passenger cars. In addition to these safety considerations, the front unit structural design has to account for an increasing number of constraints: improvement of real-world performance in safety, fulfill current and future regulations like "CAFÉ" or pedestrian, reducing utilization costs and so on. Furthermore, European fleet is changing in mass and in size, as the world's ones, and new fashion vehicles appear different than the previous one.