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New trends in the development of combustion engines lead to changed engine operating conditions which also result in changed loads of the engine parts and functional components. The application of regenerative fuels and new exhaust after- treatment systems can for example lead to an increased input of fuel into the engine oil. Oil dilution is an issue that impacts the engine operation and life cycle and therefore gains importance during the development process of combustion engines. In order to improve oil dilution to preclude destructive amounts of fuel in the oil it is necessary to investigate and optimize the fuel in oil sorption and desorption processes. At the University of Applied Sciences Regensburg a new measurement technique has been developed that realizes the online analysis of the fuel quantity in the engine oil.

The emission reduction potential of high boost and high injection pressures was investigated on a 4-cylinder small bore diesel engine at high rates of exhaust gas recirculation. For this reason an external boosting system was built up, which allowed to generate the desired boost pressure independent from the engine's operating point. In order to simulate conditions comparable to a real turbocharged engine, also the influence of the turbine on the exhaust back pressure was considered. The whole measurement campaign was carried out at two load points (low- and mid-load), which represent characteristic engine operating points of the Urban Driving Cycle (UDC). On the one hand could be shown, that there is an enormous potential in the reduction of particulate matter (PM) up to 75 % and of carbon monoxide (CO) up to 15 % at the mid-load point by increasing the boost pressure.