Internal combustion engines will be the drive system used in a great amount of cars over the next decades, despite the increasing investments in the electrification of the transport sector. The research on the combustion process in internal combustion engines focuses on the reduction of emissions, especially on the reduction of CO¬2, NOx, soot and particle emissions.
Low emissions are already achieved in stationary engine operation, whereas transient engine operations are a main cause of high emissions of modern spark ignited engines. The understanding of the effect of engine transients on the mixture formation, on the combustion process and further on the emissions is essentially for engine development.
Method and Theory
A thermodynamic single cylinder DISI engine is equipped with minimally invasive optical accesses. The mixture formation can be investigated over a wide range of transient engine operations and their impact on soot and particle emissions. The methods used to measure the vector fields and the soot emissions are particle image velocimetry and two-color thermometry, respectively.