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In this paper the performance of a new EGR cooler with double efficiency capabilities is presented. This device allows for temperature modulation between the actual cooled and non-cooled EGR temperature. The cooler has a double circuit in its interior controlled by a valve. The outer dimensions of the cooler remain the same as current fixed geometry coolers. The prototype has been characterized on test flow and thermal efficiency rigs and also tested on the engine test bed. Tests show that for steady partial load conditions little benefits may be achieved in CO and HC emissions with a small increase of NOx emissions. More promising results have been obtained during engine warm-up tests in which significant reductions of HC and CO are attained with low increases of NOx emissions. This shows a potential to reduce CO and HC emissions which are mostly generated during the first stages in the emission certification test in Europe.

The increasingly restrictive legislation on pollutant emissions is involving new homologation procedures driven to be representative of real driving emissions. This context demands an update of the modelling tools leading to an accurate assessment of the engine and aftertreatment systems performance at the same time as these complex systems are understood as a single element. In addition, virtual engine models must retain the accuracy while reducing the computational effort to get closer to real-time computation. It makes them useful for pre-design and calibration but also potentially applicable to on-board diagnostics purposes. This paper responds to these requirements presenting a lumped modelling approach for the simulation of aftertreatment systems.

This paper presents an experimental analysis on the effect of thermal insulation of engine internal walls on the performance and emissions of a heavy-duty diesel engine. Some parts of the engine, like pistons, cylinder head and exhaust manifold were thermally insulated from gas contact side in order to reduce heat losses through the walls. Each component has been analyzed, independently, and in combination with others. The results have been compared with that of the original engine configuration. The analysis focuses on NOx and, smoke emissions along with brake specific fuel consumption. In order to take advantage of the engine insulation, an optimization of the air management and injection settings was finally performed, which provided the best combination for each engine configuration.