Working principle turbocharger
A turbocharger serves to increase the performance of an internal combustion engine by providing it with additional fresh air with the help of waste gas pouring out. One calls that "loading" with fresh air, therefore an engine with a turbocharger is called "loaded engine". In contrast to this the so-called naturally aspirated engines are supplied with fresh air only by negative pressure. The fresh air is vacuumed into the top-hat, the negative pressure that is needed arises from the downward movement of the piston in the so-called induction stroke, one of the four operation cycles of an engine.
The turbocharger means a clear improvement of the supply with fresh air. In principle, it consists of two different wheels in different chambers but are connected with each other by a wave. The turbine wheel is directly at the exhaust manifold in the waste gas room of the engine and is started moving by the hot waste gases that are pouring out there - with up to 300.000 revolutions per minute.
This energy is transferred from the wave to the second wheel, the so-called turbine or compressor wheel. Its rotation draws in additional fresh air is, which is condensed in the compressor housig and led into the top-hat by means of excess pressure. So, the turbocharger makes compressed air with a higher oxygen content per volume unit reach the top-hat. At the same time, more fuel can be injected, which further increases the engine performance.
Since the turbocharger warms the charge air with the compression, in most cases also a charge air cooler is a part of the turbocharger. On the one hand, it reduces the heat stress for the engine, on the other hand it serves the efficiency increase as gasses extend at increasing temperature so that the air output is reduced in the combustion chamber. An unwanted effect which decreases the engine performance. If the warmth arisen at the compression is, however, derived by a charge air cooler, the air throughput and thus also the degree of effectiveness of the engine is higher.
Therefore, a turbocharger, particularly in combination with a charge air cooler makes a higher performance gain than a conventional naturally aspirated engine possible. In particular, it prevents the performance from levelling if at high rotational speeds. Another effect is that a car with a loaded engine reacts faster to orders of the driver. So, the turbocharger makes not only a higher engine performance possible, but also has many advantages when it comes to safety issues.
Furthermore, the turbocharger causes a more complete burning of the fuel by delivering more air into the combustion chamber than a naturally aspirated engine. A modern turbo diesel engine emits 50 percent less nitric oxides and carbon dioxide than at a comparable naturally aspirated engine.