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Mixture formation in the combustion chamber is of paramount significance for diesel combustion processes. Particularly in inhomogeneous combustion processes with internal mixture formation, the course of combustion and composition of combustion products are heavily influenced by charge motion and material transport during the compression phase and during combustion itself. Charge motion is normally quantified in steady-state flow testing. This model-based test takes place under idealized conditions. This means that with a permanently open valve and constant pressure differential over the inlet port, a steady-state flow of air is established in the simulated cylinder. The influence of piston movement is neglected. The test delivers integral characteristic flow figures, such as swirl number, flow number and tumble number.

As more virtual product development is integrated into the mass-production development process and overall development times are shortened, efficient intake-port design requires closer cooperation between design, simulation and test engineers. Doppler Global Velocimetry (DGV) has become an important link in the overall intake-port development process as it provides 3D-vector fields of flow velocity. Hence, it can be used to make direct comparisons with 3D-CFD-simulation results. The present paper describes the hardware-assisted inlet port development process for diesel engines, the cooperation among port design, 3D-CFD-simulation with the creation of alternative geometries and DGV flow-measurement of preferred variants with their capability of checking and improving simulation results.