Difference between 2-stroke and 4-stroke engine

2-Stroke Engines

A 2-stroke engine is an internal combustion engine that completes a power cycle in two strokes of the piston, occurring within a single revolution of the crankshaft.

The 2-Stroke Process:

1. Intake: As the piston moves downward, a mixture of fuel and air enters the cylinder through intake ports.
2. Power: The piston moves upward, compressing the mixture and igniting it. This produces a power stroke.
3. Exhaust: The exhaust gases are expelled from the cylinder through exhaust ports as the piston moves downward.

Advantages of 2-Stroke Engines:

• Lower cost
• Lower maintenance cost
• Lighter weight

Disadvantages of 2-Stroke Engines:

• Less efficient
• Requires more lubrication
• Prone to more wear and tear, friction, and emissions

Applications of 2-Stroke Engines:

• 2-wheeler motorcycles (e.g., Yamaha RX 100, Suzuki Samurai, TVS Max 100)
• 3-wheelers (e.g., auto-rickshaws, tempos)

4-Stroke Engines

A 4-stroke engine completes a power cycle in four strokes of the piston, spanning two revolutions of the crankshaft.

The 4-Stroke Process:

1. Intake: The intake valve opens as the piston moves downward, drawing in a fuel-air mixture.
2. Compression: Both valves close, and the piston moves upward, compressing the mixture.
3. Power: The spark plug ignites the compressed mixture, producing a power stroke as the piston moves downward.
4. Exhaust: The exhaust valve opens as the piston moves upward, expelling the exhaust gases.

Advantages of 4-Stroke Engines:

• More efficient
• Requires less lubrication
• Less friction, wear and tear, and emissions

Disadvantages of 4-Stroke Engines:

• Heavier weight
• Higher cost
• Higher maintenance cost

Applications of 4-Stroke Engines:

• 2-wheeler motorcycles (e.g., Bajaj Pulsar, KTM Duke, Hero Honda Splendor)
• 3-wheelers (e.g., auto-rickshaws, tempos)