25 Differences between Two Stroke and Four Stroke Engine

Are you looking to know the Difference between two-stroke and four-stroke engine?

Then your search ends here. Before you jump into the mainstream of the article, Let’s start with the basics by knowing an overview of two-stroke and four-stroke engines.

So, without further delays, Let’s dig in-

What is Two-stroke Engine?

One of the well-known types of Internal combustion engine is a two-stroke engine. This engine is widely used in motorcycles before the four-stroke engines.

Here combustion is the basic principle of any engine where combustion occurs using-

  • Fuel
  • Oxygen
  • Fire

Basically, a 2-stroke engine works in a two-step process- Step one is intake and compression and step two is Combustion and exhaust.

  • Intake & Compression
  • Combustion & Exhaust

What is a Four-stroke Engine?

From all types of engines, four-stroke engines are widely used especially in motorcycles.

Four-stroke engine means A engine that has four stages in one cycle. Internal combustion occurs in a closed cylinder and the result of the combustion is heat and expansion power. Further expansion power pushes the piston down and this cycle repeats.

This was the basic Overview of the two-stroke and four-stroke engines. Now, Let’s move into the mainstream of the article where we will discuss two-stroke and four-stroke engine differences.

Difference between Two Stroke and Four stroke Engine-

Two Stroke EngineFour Stroke Engine
It has one power stroke for each revolution of the crankshaft.It has one power stroke for every two revolutions of the crankshaft.
A lighter flywheel is required and the engine runs balanced because the turning moment is more even due to one power stroke for each revolution of the crankshaft.A heavy flywheel is required and the engine runs unbalanced because the turning moment on the crankshaft is not even due to one power stroke for every two revolutions of the crankshaft.
The engine is light.Engine is Heavy
Engine design is simple due to the absence of a valve mechanism.Engine design is complicated due to the valve mechanism.
Less cost than a Four-stroke engine.Costly
More mechanical efficiency due to less friction on a few parts.Less mechanical efficiency due to more friction on many parts.
Less output due to missing fresh charge with the hot burnt gases.More output due to full fresh charge intake and full burnt gases exhaust.
Engine runs Hotter.The engine runs cooler.
Air-cooled EngineWater-cooled Engine
More fuel consumption and the fresh charge are mixed with exhaust gases.Less fuel consumption and complete burning of fuel.
The engine requires less space.The engine requires more space.
Less noise is created by the engine.More noise is created by the engine.
Simple lubricating system.Complicated lubricating system.
The engine consists of inlet and exhaust ports.The engine consists of an inlet and exhaust valve.
Less thermal efficiency.Higher thermal efficiency.
It consumes more lubricating oil.It consumes less lubricating oil.
Lubricating oil is mixed with petrol and then admitted into the engine.It has a separate lubrication system.
More wear and tear of moving parts.Less wear and tear of moving parts.
The cycle is complete in a two-stroke piston.The cycle is completed in four-stroke of the piston
Power is developed in every revolution of the crankshaft.Power is developed in every alternate revolution of the crankshaft.
No. of the power stroke(n)=NNo. of the power stroke(n)=N/2
High torqueLess Torque
More smokeLess smoke
Light in overall weightHeavy in overall weight
Used for low power applications like scooters, motorcycles, auto-rickshaw etc.Used for high power applications like buses, trucks, tractors etc.

This was the basic difference between 2 stroke and 4-stroke engine. Now here is a burning question that is asked frequently-

Which is better 2-stroke and 4-stroke engine?

2 stroke engine is better due to its high RPM, more powerful than 4 stroke, simpler design, easy fixing, 


Wrapping Up-

That’s it for now. I hope, you liked the Differences between Two Stroke and Four Stroke Engine. If so, share with your near and dear ones and Bookmark Engineers Rail for further convenient readings.

Here are some more Differences, You may like to explore further


Difference Between Gear Drive and Belt Drive

Statics vs Dynamics- What’s the Difference

What’s the Difference between condenser coil and evaporator coil

What’s the Difference between condenser and Evaporator?

Difference Between Conventional and Non-Conventional Machining Processes

Thank you for being with me. I hope to see you in the next session.

Leave a comment