Two Stroke Engine Vs Four Stroke Engines

Difference between Two Stroke and Four Stroke Engines

Difference between Two Stroke and Four Stroke Engine is an important topic in Thermal engineering as well as Automobile Engineering.

So, Here is the key Difference between Two Stroke and Four Stroke Engines.

Difference between Two Stroke and Four Stroke Engines


First and the foremost difference that one can find physically between these two engines is valves and ports.

A two stroke engine has inlet port for the supply of fuel and an exhaust port for exhaust gas.

Whereas a four-stroke engine has inlet and exhaust/Outlet valve for supply of fuel and exhaust gases.

Two Stroke Engine


Four Stroke Engine


It has an inlet port and exhaust port

It has inlet valves and exhaust valves.

This engine has one revolution of the crankshaft for one power stroke.

Four stroke engine has two revolutions of crankshaft between one power strokes.

It gives more torque.

The torque produced by a four-stroke engine is comparatively less

Two stroke engine requires lighter flywheel.

It requires heavier flywheel.

Due to port system, the charge is partially burnt.

In a four-stroke engine, the charge is burnt completely.

Since oil is mixed with the fuel, lubrication is easy.

Lubrication is a complicated task.

Thermal efficiency is less.

Four stroke engine has more thermal efficiency.

Less engine weight.

Engine weight is more.

Produce more noise.

Produce less noise.

Since oil is burnt with fuel, It produces more smoke.

Four stroke engines generate less smoke.

Cost of the engine is less

Cost of the engine is more because of the valve and lubricating mechanism.

Two  Stroke engines are easy to manufacture.

Four stroke engines are comparatively hard to manufacture.

Due to poor lubrication more wear and tear occurs

Due to efficient lubrication, a four-stroke engine has less wear and tear
Two stroke engines are used in ships, scooters etc.

Four stroke engines are used in cars, truck, and other automobiles.

Also read : Difference between SI and CI Engines


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