The increasingly stringent CO₂ emissions standards require innovative solutions in the vehicle development process. One possibility to reduce CO₂ emissions is the electrification of powertrains. The resulting increased complexity, as well as the increased competition and time pressure make the use of simulation software and test benches indispensable in the early development phases. This publication therefore presents a methodology for test bench coupling to enable early testing of electrified powertrains. For this purpose, an internal combustion engine test bench and an electric motor test bench are virtually interconnected. By applying and extending the Distributed Co-Simulation Protocol Standard for the presented hybrid electric powertrain use case, real-time-capable communication between the two test benches is achieved. Insights into the test bench setups, and the communication between the test benches and the protocol extension, especially with regard to temperature measurements, enable the extension to be applied to other powertrain or test bench configurations. The shown results from coupled test bench operations emphasize the applicability. The discussed experiences from the test bench coupling experiments complete the insights.

The particle size distribution (PSD) of submicron exhaust engine-out soot, is typically determined using a method based on the electrical mobility is used. This measurement procedure is subjected to uncertainty mainly due to inaccurate dilution of the sampled aerosol, unknown flow conditions at the probe inlet and the limited measurement accuracy of the device itself. In order to determine the measurement uncertainty, two different aerosol spectrometers, a TSI EEPS 3090 and a Cambustion DMS500 were installed and operated simultaneously at a single-cylinder heavy-duty diesel engine at the Institute of Internal Combustion Engines of the Karlsruhe Institute of Technology (KIT).The engine was operated at various operating points to evaluate the ability of the spectrometers to correctly determine the PSD and the total particle number concentration (TPNC) at different boundary conditions. Variations of the position and geometry of the probe systems were performed, to evaluate the influence of the flow conditions at the probe inlet. The dilution systems of both measuring devices were verified by varying the dilution factor in three steps. Both particle sizers show good agreement in the TPNC. It could be confirmed that the probe geometry and its positioning had a negligible effect on the properties of the exhaust gas sample. A slight shift in PSD between the EEPS and the DMS was observed at the engine test bed. For a detailed evaluation, a device comparison with monodisperse polystyrene (PSL) particles with a SMPS as reference was performed at the Institute of Mechanical Process Engineering and Mechanics (KIT).