TWO STROKE ENGINE

A two-stroke engine is a type of internal combustion engine that completes a power cycle with only two strokes(movements) of the piston and one complete revolution of the crankshaft,combining the four functions of intake,compression,power,and exhaust.This design results in a high power-to-weight ratio and mechanical simplicity. 

Unlike a four-stroke engine, which uses separate strokes and valves for each function, the two-stroke engine uses ports in the cylinder walls and the piston itself to manage the flow of the air-fuel mixture and exhaust. The cycle is completed in two strokes: 

The Upward Stroke (Intake & Compression) takes place when the piston moves from Bottom Dead Center (BDC) to Top Dead Center (TDC).

Above the piston, the air-fuel mixture (or air in a diesel engine) is compressed.

Simultaneously, the upward movement of the piston creates a vacuum in the crankcase, which opens the inlet port and draws a fresh charge of air-fuel mixture into the crankcase.

The Downward Stroke (Power & Exhaust) is when the compressed mixture is ignited by a spark plug (in a gasoline engine), forcing the piston down.This downward motion produces the engine's power.

As the piston moves down, it uncovers the exhaust port, allowing the spent gases to leave the cylinder.

Further downward movement uncovers the transfer port, and the fresh, slightly compressed charge in the crankcase flows into the cylinder, helping to push out the remaining exhaust gases (scavenging). 

Due to their simple design, light weight, and high power-to-weight ratio, two-stroke engines are suited for specific applications like Power tools, Lightweight  Vehicles, Marine and industrial applications and recreational equipments.