Working of Turbochargers!

Hi Guys,

After a long time, I’m going to write a technical article. It is going to be a long series of articles related with Mechanical Engineering. My aim is that by reading these posts, common people should be able to learn something. So, let me write about Turbochargers today.

PC Game Freaks must have come across this word, while playing race games such as Need for Speed. Well, what is Turbocharger? Turbocharger is a device used to boost up the engine performance. It was earlier used in race cars, but these days it has become too common.

Before looking into Turbochargers, let us see the basics of a four stroke engine. It is the engine used in almost all automobiles today. It has got the name as the working consists of 4 strokes namely Intake, Compression, Power and Exhaust.

In Intake Stroke compressed air and gasoline are in taken (only compressed air in case of diesel engines). In Compression stroke, this mixture is compressed and during compression spark plug is ignited (in case of diesel engines, diesel is sucked in and the high pressure is enough for auto ignition). In Power stroke, due to the blast power is produced and the gases expand. In the Exhaust stroke, the waste gases are sent out.

Generally the efficiency of a gasoline engine is around 35-40%. One of the easy ways of increasing the efficiency is by increasing the air flow. All of us know about the candle light experiment. Burn a candle and place it inside a close container. It will blow off when there is no oxygen. Imagine a bigger container. It will glow for some more time. Similarly if there is no air, then some fuel will be left unburned. So, by increasing the air in taken or by increasing the air pressure, we can increase the efficiency.

Schematic Diagram of a Turbocharger

The technique is simple. Keep a turbine in the exhaust of the engine. So the exhaust gases hit the turbine. The turbine shaft is connected to the intake compressor shaft. So the exhaust air forces the compressor to spin faster and thus the pressure of the intake air is increased. Thus the power produced is increased. The increase in efficiency depends on lot of factors like size of turbochargers, though an increase of 30-40% can be expected.

Let us see another interesting topic next time.


Reference: 
Turbochargers - How Stuff Works
Forced Air and the Future - The Auto Rules

Happy Reading!!!