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In the present paper the impact of three different geometrical layouts of the discharge nozzle of a high-pressure diesel injector designed is examined for a common rail second generation direct injection system. The paper presents a comparative study of the spray behavior of the three different nozzle layouts connected to a 150 MPa rail-pressure when mounted on a 1.6 liter European passenger car engine. To evaluate experimentally the differences in the fundamental physical spray parameters several specially developed optical visualization techniques are used, which enable phase-Doppler, Laser-sheet and high-speed recordings of dense high pressure sprays. The change in basic spray parameters (time-resolved droplet distribution and spray momentum) caused by the nozzle geometry variation is examined. The impact on the in-cylinder penetration and mixing characteristics is studied with a 3D-numerical simulation code NCF-3D.

For compliance with future LEV/ULEV emission standards in United States and Euro 2000/Euro 2005 standards in European Community, catalytic converter performance has to be remarkably improved. The development of simulation codes allows to investigate a high range of possible exhaust system configurations and engine operating parameters. In the present study an hybrid Lattice BGK-finite volume technique will be described, able to determine the mass transfer rates of the chemical species to the catalyzed wall of the monolith channels. The BGK code solves the fluid motion governing equations in a reduced form obtained by discretizing the continuum in a fixed number of particles. Each of them will be moved by a set of discrete velocities and collide with the neighbour particles according to a fixed pattern of particle-interaction.