Turbochargers are an amazing invention that helps in increasing the power of the engine at lower than usual cost and without increasing the weight of the engine too much. As the world is developing, new technologies get introduced every day. The turbocharger was introduced to make the internal combustion engines more powerful and efficient. Turbochargers were introduced in cars back in 1962. Previously, only sports and performance cars had turbochargers. Now family sedans and hatchbacks also get turbochargers to increase fuel efficiency.
Cars in Pakistan have also started to get turbochargers like the Honda Civic. As the world is going green and renewable energies are being adopted at a faster rate than ever, petrol and diesel-powered vehicles are fitted with turbochargers to reduce emissions. This is achieved by using smaller engines that use less fuel but have the same output compared to bigger engines. This is because smaller engines come with turbochargers to boost power output.
What is a turbocharger?
A turbocharger is a device that works with a turbine that helps in entering extra air into the combustion chamber of an internal combustion engine. The power that an engine can produce depends upon how quickly it burns fuel. One way to increase power output is to add more cylinders to a car’s engine. This is the reason that performance-oriented cars have six, eight, or twelve cylinders. Another way to boost power is to attach a turbocharger to the engine. This is done by forcing more air into the combustion chamber so that the rate at which the fuel is being burnt increases. This puts out more power from the engine while maintaining the same size.
There are six types of turbochargers available in the market for cars. These are single-turbo, twin-turbo, twin-scroll turbo, variable geometry turbo, variable twin-scroll turbo, and electric turbo. This shows how much the turbocharging technology has evolved over the years since it was first introduced in 1962. Following is a detail description of each of these turbochargers:
Single turbochargers have a small RPM range in which they are effective. The response from a single turbocharger is also sluggish. However, it is the cheapest way to improve your engine’s power and efficiency, and it is fairly easy and simple to install. Large single turbochargers produce high-end power, while small single turbochargers produce low-end power. Torque can also be meddled with by changing the turbine and compressor wheel size. Ball-bearing single turbochargers are more efficient as they reduce friction; however, they cost more. There is limitless variability when it comes to single turbochargers. Single turbochargers are being used in hatchbacks and family sedans to increase fuel efficiency.
See the tip video below:
Twin turbochargers can be used in a parallel or sequential fashion. Usually, “V” engines like V6 or V8 use parallel twin turbochargers. In this way, each cylinder bank has a single turbocharger. You can also use a sequential integration in which one turbocharger is used for low RPM, and one or both are used for high RPM. The sequential setup is better than the parallel setup; the torque curve is relatively flat. This results in a good amount of low-end torque, and this torque does not fade away at high RPM. Complexity and cost are higher compared to single turbochargers. Twin-turbo chargers are more common in high-end and performance-oriented cars.
Compared to single turbochargers, twin-scroll turbos are superior in every aspect. The exhaust gases can be divided using two scrolls. Some cylinders in the engine get their air from one scroll, and some get from the other one. This is important as it prevents the working of one cylinder with that of the other cylinders. This improves the efficiency and power output of the engine. In this type of turbocharger, the effective RPM range for a boost in power is wider than the preceding two turbos discussed in the article. Moreover, these can be fitted to only some special types of engines and cost more and have higher complexity than a twin and single turbochargers. The design of the scrolls can be changed to increase the effective RPM range.
Variable geometry turbo
This type of turbocharger is unique and limited in production. It is usually fitted to diesel engines. The variable geometry turbocharger is complex to make and requires exotic materials. This makes it expensive to produce, and therefore, it is used less frequently by the auto manufacturers. The turbocharger changes the area-to-radius ratio in response to the RPM. This results in a low area-to-radius ratio for low RPMs and high area-to-radius ratio for high RPMs. This reduces the turbo lag and provides a flatter and wider band of the effective RPM range. This setup requires a single turbocharger and is smaller in size than a sequential setup. Some Porsche cars integrated this type of turbocharger in the past.
Variable twin-scroll turbo
This is a relatively new technology, and these are the future of turbochargers for gasoline/petrol engines. The variable twin-scroll turbocharger is cheaper to manufacture compared to variable geometry turbocharger. The design is more robust than a variable geometry turbocharger while keeping a similar flat torque curve. The cost is lower than a variable geometry turbocharger, and when its size is small, it can be very efficient in producing power. Due to its technology, the variable twin-scroll turbochargers were introduced in the past; they did not make it to the production lines. There are still challenges associated with this type of turbocharger.
An electric turbocharger has an electric motor that helps in overcoming all the shortcomings of a traditional turbocharger. These include having a turbo lag, a lower volume of exhaust gases, and insufficient low-end torque. This is achieved by attaching an electric motor with the compressor wheel. In this way, the electric motor provides power to spin the compressor whenever needed to pump more air into the cylinders. Wasted energy is also saved, and the whole process of turbocharging becomes more efficient.
Moreover, the effective range of RPM is also increased with this turbocharger. The electric turbocharger also helps in controlling carbon emissions by lowering the volume of exhaust gases emitted into the environment. The cost and complexity are highest amongst all the turbochargers discussed in this article. It also attaches the most amount of weight to the engine as it has an electric motor. There is also a battery pack onboard to power the electric motor when needed.
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