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This paper focuses on the hydraulic losses of the low-pressure diesel fuel path and the impact of these losses on the fuel consumption and therefore CO2 emissions of internal combustion engines. In this context, a 1D (one-dimensional) simulation model with implemented fluid flow physics was developed. A 3D CFD model for considering complex geometries of several fuel path components further enhances the 1D approach. Experimental data from a test bench, carrying the complete fuel pressure system, were used for validations and continuous developments of the simulation models. The results show a substantial potential of the low-pressure system regarding a reduction of CO2 emissions, depending on the control strategy of the electric fuel pump and the geometrical properties of the fuel pipes and couplings. Within the New European Driving Cycle, a potential of up to 1.1 g CO2/km was observed.

This paper presents an innovative method for the calibration of internal combustion engines. While common calibration strategies and optimizations are usually based on stationary operation points, this new method uses quasi-stationary engine experiments. On the one hand, the time necessary for establishing a steady state of the engine can thus be omitted. Consequently, the duration of calibration runs can be reduced. On the other hand, an enhanced approach generates validated data from the transient or quasi-stationary test runs in order to complete the various engine maps. First validations of the method using a numeric engine model were carried out. Compared to a conventional steady state calibration and depending on the optimization parameter, the duration could be decreased by up to 74% from 350 hours to approximately 91 hours with constant quality of the measurement data.