working of turbocharger in diesel engine

What is the working of turbocharger in diesel engine?

With the rapid development of modern science and technology, people's requirements for engine power are getting higher and higher. The most effective way to increase engine power is to increase the air flow into the engine and pre-compress the air entering the engine, that is, to use supercharging technology. The function of supercharging technology is to increase the density and quantity of gas entering the cylinder of the internal combustion engine, so as to increase the average effective pressure of the internal combustion engine, increase the power and improve the economy.

The use of supercharging technology is very necessary for engines used in high altitude areas. In plateau areas, the atmospheric pressure is low and the air is thin, resulting in a decrease in engine power. It is generally believed that for every 1000m increase in altitude, the power will decrease by 8% to 10%, and the fuel consumption rate will increase by 3.8% to 5.5%. After the turbocharger is installed, the power of the engine can be restored and the fuel consumption can be reduced.

The supercharging systems of internal combustion engines can generally be divided into three categories: mechanical supercharging systems, exhaust gas turbocharging systems and compound supercharging systems. The supercharging system is driven by the diesel engine through gears, belts, chains and other devices, and the compressed air enters the cylinder. The supercharger adopts a centrifugal or Roots compressor.

Due to the need to install a transmission mechanism on the internal combustion engine for mechanical supercharging, not only the structure of the engine is complicated and the volume is increased, but also a certain amount of power is consumed, which reduces the economy of the internal combustion engine. Exhaust gas turbocharging is to use the energy of the exhaust gas exhausted by the internal combustion engine to drive the turbine and then drag the compressor to increase the intake pressure and increase the intake air volume. The combination of supercharging and turbocharging constitutes a compound supercharging system. The compound supercharging method is mainly used for high supercharging engines.

Exhaust gas turbocharging systems are widely used in vehicle diesel engines and gasoline engines, especially diesel engines with exhaust gas turbocharging systems with intercoolers are very common. With the widespread use of turbochargers, it is very necessary for general users to have a preliminary grasp of the principles and functions of turbochargers and to adopt correct usage methods to prolong their service life and save costs.

The working of exhaust gas turbocharger: The exhaust gas turbocharging system is mainly composed of two parts: a turbine and a compressor. Turbocharging uses the inertial momentum of the exhaust gas discharged from the engine to drive the turbine in the turbine chamber, and the turbine drives the coaxial impeller, which presses the air sent by the air filter pipe to pressurize it into the cylinder.

When the engine speed increases, the exhaust gas discharge speed and the turbine speed also increase synchronously. The impeller compresses more air into the cylinder, and the pressure and density of the air increase to burn more fuel. By increasing the amount of fuel and adjusting the engine speed accordingly, the output power of the engine can be increased.

The temperature of the air after being supercharged by the compressor is higher than that of the naturally aspirated air, which is not conducive to increasing the air density. Therefore, many exhaust gas turbocharging systems introduce the air discharged from the compressor into the intercooler and then enter the engine intake after being cooled.
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