Car Engines – Naturally Aspirated vs Turbocharged : AutoGyan

This is another edition of our weekly AutoGyan where we explain the basic mechanisms of your vehicle in the most simple way possible. This week we are going to explain the basic functioning of a car engine. After that, the basic differences between naturally aspirated engines and turbocharged engine. Naturally Aspirated vs Turbocharged has something to do with the air flow inside the engine. So let us start with basic functioning of an engine.

How does the engine create power?

The power generation process of an engine involves a number of processes. A basic car engine involves intake, compression, power generation and exhaust. We will go on by one on each one. In the intake step the air and fuel flows into the cylinder. An engine has a number of cylinders. Each cylinder has one piston in it. Coming back to the intake of air and fuel. The fuel comes from injectors and the air from the intakes. When this mixture of air and fuel enter the cylinder, the piston is lowered down. Once the mixture enters the cylinder, the piston comes up.

This will lead to the compression of the gases. At this point of time, the sparkplug adds a spark to the mixture leading to a minor explosion in the chamber. This exerts pressure on the piston and it goes down. The piston is connected to a crank shaft. So this up and down movement of the piston causes the crankshaft to generate power.

The process of how power is sent to the wheels via transmission is explained in this article. Now, what happens to the gases in the cylinder? They are let out through the exhaust. This is how the engine generates power. For today’s article we are concerned with the air inflow.

What is Naturally Aspirated engine?

Naturally Aspirated or N/A engines are those which suck air into the cylinder by the vaccum created while compression. In simple words, N/A engine gets air into the cylinder by natural method without using any external force. This naturally pulled air is then pushed into the cylinders for compression as mentioned above.

What does a turbo do? and How?

The turbocharged engines use the turbo to pull in more air. This extra air helps in burning more fuel and hence more power. The turbo has two turbines in it. One of which is rotated by the hot exhaust gases and other the turbine pulls more external air from the intake and sends it to the cylinders. The exhaust gases created by a turbocharged engine enters a turbine after coming out of the cylinder. These gases spin the turbine which is connected to the other turbine. When the other turbine spins, it sucks external air. This air is then pushed into the cylinders for more combustion. But, this external air is hot and needs to be cooled down or else the engine will start heating up. This problem can be solved by using an intercooler. The air before entering the cylinder passes through an intercooler which cools it down.

Naturally Aspirated vs Turbocharged  –

The turbo charged engines were evolved due to the increasing size of the N/A engines. If you want to increase power in an N/A engine you need to increase the cylinders and size of the engine at the same times. These bigger engines are too heavy and burns a lot of fuel. The turbocharged engines are more efficient in these terms. The smaller engines can be used to create more power by the extra air pulled by the turbo which in turn burns more fuel. This creates more power. But wait a minute, if it burns more fuel, how can it be more efficient? Because the extra air is sucked only when it is needed. So, the engines can return to their original character at low speeds. This makes them more fuel efficient. The turbocharged engines too have some disadvantages like turbo lag, etc. So both the negines have their merits and demerits. The main thing, enthusiasts miss on the turbocharged engines is the sound and rev range. The turbos are more efficient but the naturally aspirated engines are more fun to drive.

Hope you learnt a bit about your car from this article. Don’t forget to share it. Happy Motoring!

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