67 Analysis of Mixture Conditions in a Small Two Stroke Engine Using a Gas Sampling Valve

The quality of mixture formation and the combustion process is of significant importance for reducing the hydrocarbon emissions of small two stroke engines. The scope of this work was to investigate the mixture conditions after the exhaust closes and after the end of combustion depending on various engine operating points. For this experimental investigation a Gas Sampling Valve (GSV) was combined with a flame ionisation detector (FID) and a CO₂-analyser. Using this technique, it was possible to measure the hydrocarbon concentration after end of combustion. Furthermore the local residual gas concentration after exhaust closes was determined.

To allow for a comparison of the experimental results with calculations with CFD codes, in cylinder pressure measurement and exhaust gas measurements are done additionally.