Two Stroke Engine
In the two stroke engine, instead of valves ports are given, these are opened and closed by moving piston. Through inlet port, the mixture of air and fuel is taken into crank case of engine cylinder and through the transfer port the mixture enters engine cylinder from crank case. The exhaust ports fulfill the purpose of exhausting the gases from the engine cylinder. These ports are over one in number and are arranged in a circumferential pattern.
A mixture of air fuel enters cylinder through the transfer ports and drives the burnt gases from the earlier stroke before it. As the piston begins to move upwards charge passes into the engine cylinder. For the rest of upward stroke the charge taken in the engine cylinder is compressed after the piston has covered the transfer and exhaust ports. At the same time the same time mixture of air and fuel is taken into the crank case. When piston reaches the end of its stroke, charge is ignited, which exerts pressure on top of the piston. Throughout this period, first of all exhaust ports are uncovered by the piston and so the exhaust gases leave from the cylinder. The downward movement of piston causes the compression of charge taken into the crank case of the cylinder. When piston reaches the terminal of the downward stroke. The cycle repeats.