4 STROKE ENGINE

• 4 stroke engine completes 2 rotations of crankshaft after completing one cycle
• Power is produced once every 4 strokes of the piston.
• Engine design is a bit complicated due to valve mechanism which is operated through gear & chain mechanism
• Engine design is a bit complicated due to valve mechanism which is operated through gear & chain mechanism
• Mixture remains only in the combustion chamber

2 STROKE ENGINE

• 2 stroke engine completes 1 rotation of crankshaft after completing one cycle.
• Power is produced once during 2 strokes of the piston.
• 2 stroke engine has ports which makes it's design simpler.and addition of oil is required
• A bump or protuberance may be needed on top side of piston.
• Air-fuel mixture enters through inlet port & travels to combustion chamber passing through crankcase.
• 2 stroke engines are lighter and louder comparatively.

ADVANTAGES OF 4 STROKE ENGINE :-

More torque :- In general, 4 stroke engines always make extra torque than 2 stroke engine at low RPM. Although 2 stroked ones give higher torque at higher RPM but it has a lot to do with fuel efficiency.

More fuel efficiency :- 4 stroke engines have greater fuel efficiency than 2 stroke ones because fuel is consumed once every 4 strokes.

Less pollution :- As power is generated once every 4 strokes & also as no oil or lubricant is added to the fuel; 4 stroke engine produces less pollution.

More durability :- We all know that more the engine runs, quicker it wears out. 2 stroke engines are designed for high RPM. If an engine can go for 10000 rpm’s before it wears out; a 4 stroke engine with 100 rpm will run for 100 minutes than the other 2 stroke engine which has a higher rpm of 500 & will run for only 20 minutes.

No extra addition of oil :- Only the moving parts need lubrication intermediately. No extra oil or lubricant is added to fuel.

DISADVANTAGES OF 4 STROKE ENGINE :-

Complicated design :- A 4 stroke engine has complex valve mechanisms operated & controlled by gears & chain. Also there are many parts to worry about which makes it harder to troubleshoot.

Less powerful :- As power gets delivered once every 2 rotations of crankshaft(4 strokes), hence 4 stroke is less powerful.

Expensive :- A four stroke engine has much more parts than 2 stroke engine. So they often require repairs which leads to greater expense.

ADVANTAGES OF 2 STROKE ENGINE :-

Simple design & construction :- It doesn’t have valves. It simply has inlet & outlet ports which makes it simpler.

More powerful :- In 2 stroke engine, every alternate stroke is power stroke unlike 4 stroked one in which power gets delivered once every 4 strokes. This gives a significant power boost. Also, the acceleration will be higher & power delivery will be uniform due to same reason.

Position doesn’t matter :- 2 stroke engine can work in any position as lubrication is done through the means of fuel (as the fuel passes by through whole cylinder & crankcase).

DISADVANTAGES OF 2 STROKE ENGINE :-

Less fuel efficiency :- For every alternate power stroke, fuel gets consumed every alternate stroke. This makes the engine less fuel efficient although it results in uniform power delivery.

Oil addition could be expensive :- Two-stroke engines require a mix of oil in with the air-fuel mixture to lubricate the crankshaft, connecting rod and cylinder walls. These oils may empty your pockets.

More pollution :- 2 stroke engine produces a lot of pollution. The combustion of oil added in the mixture creates a lot of smoke which leads to air pollution.

Wastage of fuel :- Sometimes the fresh charge which is going to undergo combustion gets out along with the exhaust gases. This leads to wastage of fuel & also power delivery of the engine gets effected.

Improper combustion :- The exhaust gases often get trapped inside the combustion chamber. This makes the fresh charge impure. Therefore maximum power doesn’t get delivered because of improper incomplete combustion.