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Due to the stringent emission standards modern engine concepts require special equipment for reducing exhaust pollutants and minimizing fuel consumption. Usually all those engine functions are managed by an electronic engine control unit (ECU). A good potential for emission reduction is dependent on a well optimized set of calibration maps, tables and constants, contained in the ECU. The time to evaluate an optimum data design strongly depends on the number of these calibration parameters. With an increasing number of such parameters, there is a need for sophisticated test systems which automatically initiate parameter variations, perform necessary measurements and search for an optimized engine calibration. VEGA is an automatic optimization system that controls the whole calibration process from the first basic mapping until the final programming of the ECU.

It can be expected that the high speed DIdiesel enginewill play a major role as a drive system for passenger cars and light duty vehicles. The reason is its fuel consumption which is the lowest of all combustion engines. Of course, low exhaust emission levels expecially particulates (PM) and nitric oxides NOx are a requirement in this context. Exhaust gas recirculation (EGR) can contribute decisively to achieve acceptable emission levels with high speed DI diesel engines. On the basis of fundamental investigations into the influence of EGR on the combustion process of DI diesel engines, it will be shown how the exhaust gas should be recirculated to obtain effective emission reductions. In particular, it was found that so called “Hot EGR” which keeps the temperature of the recirculated exhaust gases at a very high level, not only helps to reduce NOx but also contributes distinctly to achieve lower hydrocarbon (HC) and PM emissions.