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Due to its high benefit-cost ratio, decreasing mechanical friction losses in internal combustion engines represents one of the most effective and widely applicable solutions for improved engine efficiency. Especially the piston group - consisting of piston, rings and pin - shows significant potential for friction reduction, which can be evaluated through extensive experimental parameter studies. For each investigated variant, the steady-state friction measurements are fitted to an empirical polynomial model. In order to calculate the associated fuel consumption and CO2 emissions in transient driving cycles, the steady-state friction model is used in a map-based vehicle simulation. If transient engine operation entails friction phenomena that are not included in the steady-state model, the simulation could yield erroneous fuel consumption and CO2 predictions.

The oil emission of a combustion engine has a direct influence on CO2 and particulate emissions. The focus on reducing oil emission is thus particularly growing in the context of stricter emissions limits for the automotive industry. To reach this goal requires a deeper understanding of the mechanism behind the genesis of oil emission in a combustion engine. In order to determine oil emission caused specifically by the piston group, part of the exhaust gas flow is taken and analyzed using a mass spectrometer directly downstream of the exhaust valve in the exhaust manifold. In the process, the mass spectrometer is operated in high-pass filter mode to detect long-chain hydrocarbons associated with the lubricating oil. In order to make differentiated and detailed statements about oil emission mechanisms, oil emission and blow-by in steady-state and transient engine operation are determined for specific design parameters of the piston group.