The core components of diesel turbocharger are the turbine and the compressor impeller, which are connected with the help of a shaft. The operation of engine turbocharger is very simple, that is, high-pressure exhaust turbine makes engine turbocharger to do the high-speed rotation, at the same time, it also drives the impeller to do the high-speed rotating, the impeller thus can high-speed compress the air. The rotation is very high, and now, the car-used turbo speed is between 12-20 million rotations.
The turbine is used to transfer the kinetic energy of the exhaust into high-speed rotating of the shaft, and the function of the impeller is to compress the air, therefore, the shapes of these two components are totally different, and the air-flow movement directions of these two parts are also thoroughly inconsistent. As the turbine has to bear the high-temperature and high-pressure exhaust transferred from the
turbocharger, so it has quite high requirement for the material.
The power of the diesel turbocharger is from high-temperature and high-pressure exhaust gas, and hence it will not consume the efficiency of the engine, which is different from the case that the mechanical turbocharger will consume 7% of engine efficiency. Besides that, engine turbocharger is directly connected with the exhaust pipe, so its structure is compact.
The greater the pressure is, the greater the power is, and it is the true portrayal of the engine turbocharger. The engine turbocharger would be more powerful with the increase of speed. With the increase of the engine speed, the discharged pressure will become bigger and bigger, and the power of the impact turbine is greater, the speed of the whole rotor will be rapidly increased, the compressor impeller is thus high-speed rotated. The pressure-increased value of the general non-performance household cars is far below 1, which is generally between 0.3 and 0.5, so it can balance the performance and the fuel consumption as well as the service life of the engine.
The
diesel turbocharger has simple structure, and engine turbocharger will not consume the efficiency of engine, the pressure-increased value is also high, all of these factors make engine turbocharger own powerful advantages. However, such turbo principle of engine turbocharger lets it have one biggest potential threat, namely, high temperature. The high-temperature sources are from the following three aspects. The first is the temperature of exhaust gas. Second, the connected turbine and the shaft of the impeller are doing the tens of thousands of high-speed rotation, the friction between the shaft and bearing will thus result in plenty of heat. Finally, the inhaled impeller continues to inhale air, to compress air, its temperature will thus increase. Because of this potential threat, the turbo has not yet entered the civilian-used field.
