Analysis of Total and Individual Hydrocarbon Components in the Exhaust and Inside the Cylinder of a Two-Stroke Engine 920728

Analysis and evaluation of total and individual hydrocarbon components during the scavenging process is desirable for possible improvements in fuel consumptions and emissions for small two stroke gasoline engines.

Experiments were carried out to analyse and understand the history of hydrocarbons near the exhaust port using a high speed electromagnetic gas sampling valve and the gas chromatography technique. The analysis showed that during the scavenging process initially the hydrocarbon concentration decreases, goes to a minimum level around bottom dead centre and increases again to its maximum level. The analysis of the composition of the individual hydrocarbons (C1 to C6) was carried out near the exhaust port and inside the cylinder. The composition of gases near the exhaust port predominantly consists of hydrocarbons having higher carbon numbers (C5 and above). The in-cylinder gases (during expansion) contain a higher proportion of hydrocarbons with lower carbon numbers.