Improved Design of Air Flow for A Two Stroke Internal Combustion Engine Without Scavenging Problems to Promote Cleaner Combustion

In the present work, an attempt is made to reduce scavenging problems by developing a new model of two-stroke spark-ignition engine. This model allows the flow of fresh air through intake valves positioned at the bottom of the cylinder and exit of burnt gases through exhaust ports situated at the top of the cylinder. The exhaust ports are closed by the piston as it moves towards the bottom of the cylinder following which gasoline is injected minimizing the possibility of mixing of fuel with outgoing exhaust gases. During the expansion, the piston unravels the exhaust ports and the burnt gases escape to the atmosphere due to pressure difference. Due to low density at high temperatures, the exhaust gases naturally rise against gravity, reducing the possibility of mixing with incoming fresh air. Further, the investigation on fuel distribution inside the cylinder showed a better distribution during injection against gravity, which promotes cleaner combustion. The combustion analysis was done using Diesel-RK software and flow analysis was done using ANSYS FLUENT.