A 4-stroke petrol engine is like a mini-explosion machine that converts fuel energy into mechanical energy, turning your car's wheels. Here's how it works in four steps:
1. Intake Stroke:
* The piston moves down, creating a vacuum in the cylinder.
* The intake valve opens, allowing a mix of air and fuel (petrol) to enter the cylinder.
2. Compression Stroke:
* The piston moves up, compressing the air-fuel mixture.
* This compression increases the mixture's temperature and pressure, getting it ready to burn.
3. Power Stroke:
* A spark plug ignites the compressed fuel-air mixture, causing a rapid explosion.
* This explosion pushes the piston down, creating power that is transferred to the crankshaft.
* This power turns the wheels of your car.
4. Exhaust Stroke:
* The piston moves up again, pushing the burnt gases out of the cylinder through the open exhaust valve.
* The cycle repeats, with each stroke taking about 1/2 of a revolution of the crankshaft.
Key Components:
* Piston: A moving part that slides up and down inside the cylinder, converting energy from the explosion.
* Connecting Rod: Connects the piston to the crankshaft, transferring power.
* Crankshaft: Rotates, converting the piston's linear motion into rotational energy.
* Valves: Control the flow of air, fuel, and exhaust gases.
* Spark Plug: Ignites the air-fuel mixture.
The Cycle in Action:
Imagine the engine as a constantly repeating cycle of breathing, compressing, exploding, and exhaling. Each cycle produces power, and multiple cycles working in sequence create smooth motion.
Key Points to Remember:
* Fuel: Petrol engines use gasoline as fuel.
* Ignition: The spark plug is crucial for initiating combustion.
* Cooling: Engines need to be cooled to prevent overheating.
* Lubrication: Oil lubricates moving parts, reducing friction and wear.
Simplified Analogy:
Think of it like a bicycle pump. You push the piston down (intake), compress the air (compression), release the air with force (power), and then push the piston back up to remove the air (exhaust).
Important Note: This is a simplified explanation. The actual process involves many intricate details and components, but this overview provides a basic understanding of how a 4-stroke petrol engine works.
