Automotive turbocharger principle and advantages

Source of turbocharger

In the 1920s, ships began to be equipped with turbo diesel engines. During the Second World War, the US fighter jets also used turbos in large numbers to solve the problem of insufficient air intake by fighter planes at high altitudes. Many of them were famous fighter jets such as the B-17 air fortress and the B-24 bomber. P-38 Lightning and P-47 Lightning Fighter.

Exhaust gas energy

After the combustion of the engine, the mixed gas is called exhaust gas. However, this exhaust gas still contains a lot of energy. Exhaust temperature during normal engine full-load operation is approximately 750-900°C. Exhaust pressure depends on the operating state of the engine, but often has several times the atmospheric pressure value. At the moment when the exhaust valve is opened, the exhaust gas flow rate can reach 500-700 m/s. This kinetic energy is quite large, and it can be wasted if it is not used.

Turbocharger principle is very simple and extremely complex

Since the energy of exhaust gas is still great, it can be wasted without using it. Therefore, the engineer thought that the use of kinetic energy of exhaust gas is just like the impact force of hydropower station using water, and the exhaust gas is used to push the supercharger to produce the supercharging effect, so the exhaust gas turbocharger is named.

The core components of the turbocharger are the turbine and the compressor wheel, both of which are connected by a rotating shaft. Turbocharger work is very simple, high-pressure exhaust gas impacts the turbine to make it rotate at high speed, at the same time, it drives the impeller to rotate at high speed, and the impeller can compress air at high speed. This speed is very high, and now the turbocharged speed of the car is between 12-20 million revolutions.

The role of the turbine is to convert the kinetic energy of the exhaust gas into high-speed rotation of the rotating shaft. The role of the impeller is to compress the air, so the shapes of the two are completely different, and the direction of movement of the air flow is also completely inconsistent. As the turbine is subjected to high temperature and high pressure exhaust gas from the engine, the material requirements are extremely high.

Turbocharger advantages

The power of the turbocharger comes from high temperature and high pressure exhaust gas, so it does not consume the engine's own power. This is totally different from the case where the supercharger consumes 7% of the engine's power. In addition, the turbocharger is directly connected to the exhaust pipe and has a compact structure.
The greater the pressure, the greater the power is the true portrayal of the turbocharger. The supercharger value of the supercharger is generally below 0.5 bar, and the power consumption of the engine is also increased as the speed increases. But turbochargers have no such drawbacks at all, but they will be more powerful because of the increase in speed. Because as the engine speed increases, the exhaust pressure will increase, the impact turbine will have more force, the entire rotor speed will increase rapidly, and the compressor wheel can also rotate at high speed.