How Turbochargers Work in Cars

Government regulations surrounding fuel efficiency in new vehicles are becoming more stringent, causing automakers to turn their backs on the once-beloved V8 engine. In order to meet the power desired by buyers and government efficiency standards, manufacturers are making turbochargers the new norm.

We previously discussed how an internal combustion engine (ICE) works in modern vehicles. A turbocharger enhances the power of an ICE by forcing extra air into the combustion chamber. By increasing the amount of air available for combustion, turbochargers give efficient four-cylinders a power boost without sacrificing fuel economy. Here’s an in-depth look at how turbochargers work.

Basic Principle of Turbochargers

The basic principle behind a turbocharger is to use the engine’s exhaust gases to drive a turbine, which in turn powers a compressor. This compressor forces more air into the engine’s cylinders than would naturally be available, improving the engine’s efficiency and power output.

Components of a Turbocharger

1. Turbine: The turbine is set in the exhaust stream. As the exhaust gases leave the engine, they pass through the turbine, forcing it to spin.
2. Compressor: Connected to the turbine by a shaft, the compressor sits in the intake stream. As the turbine spins, it drives the compressor, which draws in and compresses air before forcing it into the engine’s intake manifold.
3. Intercooler: The compressed air from the compressor is hot and can reduce engine efficiency, the opposite of what turbochargers should do. The intercooler cools this compressed air before it enters the engine, making the entire combustion process more efficient.
4. Wastegate: This component controls the boost pressure by releasing some of the exhaust gases away from the turbine when the maximum pressure is reached, preventing over-boosting that could damage the engine.

How a Turbocharger Works

1. As the engine runs, it produces exhaust gases. These gases are directed to the turbocharger’s turbine housing.
2. The high-pressure exhaust gases force the turbine to spin. Since the turbine is connected to the compressor via a shaft, this also causes the compressor to spin.
3. The spinning compressor draws in extra air, compresses it, and sends it to the intercooler.
4. The intercooler cools the compressed air, making it denser and more oxygen-rich.
5. The cooled, compressed air is then forced into the engine’s intake manifold, then into the combustion chamber where it mixes with fuel.
6. With more air available in the combustion chamber, more fuel can be burned, resulting in a more powerful explosion and more power being produced by the engine.
7. To prevent the turbo from entering dangerous levels, the wastegate opens to release excess exhaust gases away from the turbine.

Benefits of Turbochargers

1. Increased Power: Turbochargers can significantly increase an engine’s power output without needing to increase its size. For example, the 2025 Honda Civic Si features a 1.5-liter turbocharged four-cylinder engine that generates 200 hp.
2. Improved Efficiency: By making more efficient use of exhaust gases and improving the air-fuel mixture, turbocharged engines can achieve better fuel efficiency.
3. Reduced Emissions: More complete combustion means fewer pollutants are released into the atmosphere.

How Turbochargers Work

Turbochargers are a highly effective way to boost an engine’s power and efficiency by utilizing exhaust gases that would otherwise go to waste. Through careful design and engineering, modern turbocharged engines deliver impressive performance, making them a popular choice in everything from trucks to muscle cars to compact sedans.