An Engine is a device which transforms one form of energy into another form of Energy. An internal combustion engine is a heat engine where it undergoes different cycles of operations in a sequent manner to convert the thermal energy into useful work. In the previous articles, we have discussed the 2 stroke engine and the 4 stroke engines working principles, in this article we are going to compare the 2 stroke vs 4 stroke engine.

Working Principle of Engines

IC engines work on either Spark ignition or the Compression Ignition working principle.

Spark Ignition: Usually a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug

compression ignition: Generally the Diesel Engines, where the combustion process is caused by the elevated temperature of the air in the cylinder due to the mechanical compression.

Both the 2 stroke engines and the 4 stroke engines can work with the spark ignition and the compression ignition system. Check the classification of the heat engines here.

Comparison of 2 Stroke vs 4 Stroke Engine

The following are the major differences between the 2 stroke and the 4 stroke engines. one of the major difference between the 2 stroke engine and the 4 stroke engine is that the method of taking the charge(Air/fuel mixture) into the cylinder. And exhausting the combustion products from the cylinder.

2 Stroke Engine	4 Stroke Engine
One power stroke for one revolution of the crankshaft.	One power stroke for two revolutions of the crankshaft.
For greater output compared to the four-stroke engine. Theoretically twice the power output than the four-stroke. (But actual practice the power is increased by 30%)	Less power output than the two-stroke engine due to one power stroke for every two revolutions of the cranks shaft.
Two-stroke engines will have the ports. (Port: Fluid can be operated inward and outward direction)	Four stroke engines will have the Valves. (Valve: The fluid can be operated in one direction only)
More uniform torque can be generated than the four-stroke.	Less uniform torque can be generated than the two-stroke.
Less effective fuel usage in two-stroke petrol engines. (During scavenging, The inlet port and the exhaust port are open at the same time so that there is a chance of escaping of the fresh charge from the cylinder)	More effective fuel usage. (Due to valve operation four stroke engine have the full advantage of using the fuel efficiently)
Less thermal efficiency with high fuel consumption.	High thermal efficiency with less fuel consumption.
Consumption of the lubricating oil is high.	Consumption of the lubricating oil is low compared to Two-stroke engines.
Due to the compact design of two-stroke and the high power output, these are used in motorcycles, scooter, and outboard engines.	Four stroke engines are used in all four wheelers, trucks, heavy vehicles.
Two stroke engine Cannot be able to operate the same efficiency at all speeds.	Can be able to operate the same efficiency at all speeds.

Conclusion

These are the major differences between the 2 stroke vs 4 stroke engines. the 2 stroke engine and the 4 stroke engines are explained in detail in these articles: 2 Stroke, 4 Stroke. Please leave your thoughts in the comment section below.