The piston assembly is a crucial system to internal combustion engines. It is a highly complex tribological system formed by the piston, multiple piston rings and the liner. Furthermore, the lubricating oil and gases inside the combustion chamber and the crank case need to be considered. The piston assembly has big influence on the engines behaviour regarding frictional losses, oil emissions, wear, blow-by and acoustics. Even though a lot of research has been performed on these topics, especially the fuel and oil flow (often carried by combustion chamber or crank case gas) is not fully understood yet.

This CORNET project “Fuel/Oil Flow Measurement” addresses this lack of knowledge by developing and enhancing new measurement techniques to determine the oil film thickness, fuel and oil flow within the piston assembly and the oil emissions. In order to do so, engines with a glass window inside the cylinder liner are developed and used. Both, SI and CI engines types are investigated. In order to visualize oil film thickness and the oil flow through the piston assembly, two different measurement techniques will be installed: laser induced fluorescence (LIF) and photochromism (PC). By combining both methods we will be able to use the advantages of both techniques to dramatically increase the value of measurement data received. In addition to measurement of oil film thickness as well as fuel and oil flow, oil emissions will be measured. This unique combination and enhancement of new and established measurement techniques will lead to a deeper understanding of tribological phenomena within the piston assembly.

The outcomes will help to enhance optical measurement techniques, not only in the area of internal combustion engines. Deeper understanding of fuel and oil flow inside the piston assembly will directly support the development of new, both ecological and economical enhanced engines. The research data generated will be helpful in order to develop powerful simulation tools in order to support engine development in the future. This will lead to a decrease of global CO2 emissions due to higher mechanical efficiency of the engines and reduced oil consumption. Considering the large number of engines sold worldwide every year even small improvements will have a meaningful impact on the environment, leading towards the age of environmentally sustainable mobility.

The project consortium consists of two research associations - AICE and FVV - and four research and technology (RTD) performers from Germany and Japan: Tokai University, Tokyo City University, Institute for Analytical Measurement Technology Hamburg (IAM) and Technical University of Munich - Chair of Internal Combustion Engines (LKV)