The new Euro 6 emission limits represent a major challenge to the development of internal combustion engines. One way to achieve this goal is to enhance the 1D engine process simulation of supercharged engines. In contrast to the widely-used 1D-modelling of pipe flow, turbochargers are generally modelled using maps of mass flow and efficiency. The turbines of turbochargers are usually mapped with constant back pressure and constant inlet temperature on special test beds. Standard non-dimensional values for flow and impeller speed should allow the turbine operating point to be recalculated depending on its boundary conditions. This procedure does not work sufficiently for operating conditions that, e.g. occur in two stage turbocharging or at high temperature offsets to the mapping conditions. This especially concerns the turbine efficiency. Methods like varying the turbine inlet temperature and the turbine back pressure expand the information of the turbine characteristic map. Both methods, used as additional boundary conditions, improve the precision of 1D simulation. The effects of the adjustments will be demonstrated using the example of a 1D engine process simulation of a turbocharged engine.

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