Operation principles

Diagram of air circulation in the turbocharger


1- air intake
2- side-on channel of the compressor
3- side-on channel of the compressor
4-The intake manifold - air supply
5- exhaust manifold - exhaust outlet
6- side-on section of the turbine - fumes hit the rotor blades of the turbine – they drive it
7- discharge of exhaust gas from turbocharger to the exhaust system

How do the turbocharges work?

Although once turbochargers were used only in sports cars , today we find them every day in all kinds of vehicles - both diesel and gasoline .

Boost is one of the easiest ways to increase engine power. It consists of air pumped into the cylinders. The turbocharger is the most popular type of this kind of device. Mostly it is combined with the diesel engine.

Combustion of the fuel in the engine - the mechanism

To could look closer to the principle of fuel combustion it is worth to take as an example four-stroke engines that are today the most commonly used. Their duty cycle consists of four strokes. The first – choke - occurs when the piston reaches out and air sucks (in the diesel engine) or when a mixture occurs (on gasoline). Then, the compression occurs, after that there is expansion. This is how it comes to ignition of the mixture of fuel and air. The last phase is the removal of exhaust gases.

Thanks to the simplicity of this principle is possible to increase the engine power by using different techniques.

One of them is an increase in cubic capacity.

This mechanism works in such way that the more the combustion chamber is increased , the more fuel will be able to be burnt. To achieve this it is necessary to enlarge the volume of each separate cylinder or to increase their number. The engine of greater weight and size allows for a slight increase in capacity, if we do not take into account fuel consumption and emissions.

Another method is to increase the pivotal speed.

It means that in one unit of time there is more strokes taken. Unfortunately, it is very limited method and it has some drawbacks. In fact it may cause the increase of friction and thus the gradual reduction of engine efficiency.

In engines having a turbo boost, air used in the combustion is compressed before it is in the combustion chamber, contrary to the above-described cases in which gases escape from the engine in a natural way and the air - necessary to ensure that - is sucked by the intake valve directly into the cylinder. The increased pressure enables to get into the combustion chamber more air, although it is sucked to the same cylinder volume. As a result, we have more fuel to burn, and thus more powerful engine, resulting in spite of the same pivotal speed and cubic capacity. While compressing the air reaches the heat up to about 180 degrees Celsius. Then, while being cooled in intercooler, it becomes denser, raising even more engine power.

One of the methods that has a positive impact on engine power is to lower the air temperature. It helps to reduce fuel consumption and exhaust gas, and thus - harmful nitrogen oxides by receiving a lower air inlet temperature and ignition. Mechanical and turbocharging chargings differ from each other.

Mechanical boost: to compress the air that is necessary for combustion, the engine driven compressor is used. However, to operate it needs energy, which loss affects the relatively small increase in power. Possible to achieve increase in capacity is on average 10-15%, and its size depends e.g. on the dimensions of the engine. Such solution, a mechanical supercharger - compared to non-supercharged engine of such power - affects the increase in fuel consumption.

Turbocharging boost :in this case we use the exhaust energy that is consumed to drive a turbine, located on the same shaft as the compressor. The task of the compressor is to intake and compress the air and passing it on to the engine. The connection between the engine and turbocharger is not mechanical, their cooperation is possible through the bond of gas.