NA (Naturally Aspirated) Engine

The naturally aspirated engines are the engines that pull air through normal pressure. Many old cars and modern new cars use this engine for its simple design and durability. These engines are reliable and easy to maintain.

How does the NA engine work?
The NA engine has four-stroke cycles to create the power that is needed to drive the vehicle.

1. In-Take Stroke – When the vehicle is started and the accelerator is stepped on, the throttle valve opens, pulling air from the atmosphere. At the same time, the piston moves downwards, developing a vacuum. This vacuum pulls the air that enters into the intake manifold. The fuel injectors spray the fuel, which forms the air-fuel mixture.
2. Compression Stroke – Once the intake stroke is completed, the intake valve closes and the piston inside the cylinder moves upwards which compresses the air-fuel mixture. This increases the temperature of the air-fuel mixture and makes it thick.
3. Power Stroke – When the piston reaches the top of the cylinder, along with the mixture, the spark plug ignites, and the compressed air-fuel mixture is burned. This burning mixture produces high gas pressure, and this pressure moves the piston downwards, which produces the mechanical energy, and this energy(motion) is transmitted to the crankshaft, which converts the piston’s linear up-down motion into circular motion. This motion is transmitted into the gearbox and finally into the differential, which rotates the wheels and moves the vehicle forward.
4. Exhaust Stroke – Now the exhaust valve opens up and the piston moves upwards, which squeezes out the exhaust gas (waste gas) from the cylinder. Finally, the waste gas leaves the cylinder via the exhaust manifold and is directed to the atmosphere via the exhaust chamber.

Advantages of the NA Engine:

1. Simple design and easy to repair.
2. Linear and predictable power delivery.
3. More reliable compared to a Turbo engine.
4. Costs less to buy and maintain
5. Fuel efficient.

Disadvantages of the NA Engine:

1. Less power of size – Smaller displacement engines make less power.
2. Engine Modifications is complex.
3. High engine revs consume more fuel.
4. Performance is very linear.