Question

The ascending order of strokes in four stroke engine is
(A) Suction stroke - Expansion stroke - Compression stroke - Exhaust stroke
(B) Suction stroke - Compression stroke – Expansion stroke -Exhaust stroke
(C) Suction stroke – Expansion stroke Exhaust stroke Compression stroke
(D) Suction stroke Compression stroke - Exhaust stroke - Expansion stroke

Answer 1

Hint: In this question we will understand about What is Four Stroke Engine is. Intake Stroke, Combustion stroke, power stroke, exhaust stroke and application of stroke engine.

Complete answer:
Four stroke engine: A four stroke engine has four sequential steps starting from intake, compression, power, to exhaust. Each equates to one full stroke of the piston. Therefore, it supplies one power stroke for every two cycles of the piston (or four piston strokes) and a complete cycle requires two revolutions of the crankshaft.
The 4 stroke engine has four steps that are described below
Stroke 1: Intake Stroke
It draws an air-fuel mixture into the combustion chamber. The piston descends in the cylinder bore to empty the combustion chamber. When the inlet valve opens, atmospheric pressure pushes the air-fuel charge into the evacuated chamber.
Stroke 2: Combustion Stroke
The cylinder is completely filled with the maximum mixture and the intake valve seals the mixture and the piston moves upward.
The compression occurs between the piston and the cylinder head.
Stroke 3: Power Stroke
After the completion of the compression stroke, the spark ignites the air-fuel mixture and forces the piston back down the cylinder bore to generate torque in the crankshaft.
The pressure on the piston determines the amount of torque generated.
Stroke 4: Exhaust Stroke
The exhaust stroke occurs when residual gases expelled from the combustion chamber are liberated into the atmosphere. The exhaust stroke is the concluding stroke and takes place when the exhaust valve is open and the intake valve is closed. Piston movement liberates exhaust gases into the atmosphere.

Applications of 4 Stroke Engine:
The four-stroke engine is the most commonly used engine at present, especially the one that specifically uses gasoline as fuel. Vehicles like cars, trucks, and some motorcycles have four stroke engines. Other applications are small propeller aircraft, formula one, small motor-powered boats, auto-rickshaw, water spray systems, etc. they all have a four-stroke engine.

Note:
Four-stroke engines have several benefits over two stroke engines. They have better fuel efficiency, durability, give more power and hence more torque and cleaner emissions. But these are more expensive and complicated to make and they need valves for intake and exhaust of gases.