A turbocharger or turbo, is a mechanism incorporated into an internal combustion engine, which significantly increases it’s power without increasing the weight. ‘Turbocharger’ is the short form for turbine-driven super charger. Turbochargers are a type of forced induction systems, which compresses the air flowing into an engine. The advantage of compressing the air is that it allows more air to enter the combustion cylinder. More air would mean more fuel can be forced-in, which in turn means more power output. Thus, each power-stroke of the engine would give more power compared to a naturally-aspirated engine.

A turbocharger as well as a supercharger works on this same principle. However, a turbocharger differs by the fact that the compressor system is powered by a turbine driven by the engine’s own exhaust gases. A supercharger, however, would be powered mechanically by a belt, gear, shaft, or chain connected to the engine’s crankshaft. The turbocharger is thus,  far more efficient. It usese the exhaust flow from the engine which spins a turbine, which in turn spins an air pump. The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons. The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin. Due to the high speeds in which the turbine has to spin, it is supported using a fluid bearing. Oil is constantly pumped around the shaft. This cools the shaft and some other parts and also allows the shaft to spin without much friction. Also, air when compressed would heat-up. At higher temperatures, air would expand. So, it is necessary to cool down the compressed air, and for this purpose, a cooling system is used as well.

A turbo is expected to provide a 30 to 40 percent power improvement. However, one of it’s major shortcomings is the fact that there is a considerable delay in providing the power-boost. This is because, it takes some time for the turbine to get up to speed when you step on the gas. This results in a feeling of ‘lag’ when one steps on the throttle. However, this can be reduced by reducing the inertia of the rotating parts. Reducing the weight of the turbine would help it to get rotating faster, and provide the boost earlier without any ‘lag’. Thus, a small turbocharger will provide boost quicker and at lower engine speeds, while a larger one would be able to provide lots of boost at higher engine speeds. Some engines thus have two turbos – a small one acts at lower speeds reducing lag and spinning up to sped quickly, whereas a larger one takes over at higher speeds.

At high altitudes, where the air is thinner, a normally aspirated engine would struggle as it’s air intake for each stroke is lesser in comparison. A turbocharged engine would also have reduced power, but the reduction would be les dramatic in comparison. Once a turbocharger is fitted into a car, it’s fuel-injection system normally steps-up the amount of fuel to be injected. Older cars with carburetors automatically increase the fuel-rate, whereas modern cars with fuel-injection system might sometimes have some difficulty. At times, the software programmed into the controller will not allow greater fuel-injection, or the pump and injectors are not capable of supplying more of fuel. Another disadvantage with the turbo-engines, is that it leads to increased chances of knocking. (Knocking happens because, as the air is compressed, it’s temperature might increase enough to ignite the fuel before the spark plug fires). This can be kept in check by using high-octane fuels. Whatever be the cons, turbochargers are in widespred use in the racing fraternity. Formula1, the pinnacle of motorsport, has banned turbochargers now, but F1 used the system until then.

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