The oil emission of an internal combustion engine has a direct impact on CO2 and particle emission. Thereby reducing the oil emission, especially in the context of stricter emission requirements in the automotive industry, is becoming a center of attention. To achieve this goal, a deeper understanding of the mechanisms of the formation of the oil emission in the internal combustion engine is necessary. In order to determine the oil emission caused by the piston group, the exhaust is sampled and analyzed via a mass spectrometer in the exhaust manifold directly after the exhaust valve. For the detection of the lubricating oil, which contains long-chain hydrocarbons, the mass spectrometer is operated in the high-pass filter mode. The oil emission is evaluated in stationary and transient operation of the engine for assessing specifically selected design parameters of the piston group, in order to make differentiated and detailed statements about the oil emission mechanisms. For the studies in the transient engine operation a specially developed high dynamic engine running program is used. Characteristic figures for the dynamic oil emission can be calculated using a standardized and fully automated evaluation tool. These figures indicate the influence of different design measures of a piston and ring variant on the oil emission. This publication describes the measuring system, the specially developed test procedure and the impact of design measures on the piston, such as the number of oil drain holes in the area of the oil control ring, on the oil emission. With a better understanding of the oil emission mechanisms oil emission and thereby CO2 emissions can be minimized effectively.