Automobile exhaust gas turbine system, the working principle of exhaust gas turbocharger

I'm a kind-hearted person, and I don't usually copy other people's books, so I don't write as much as others.

The turbocharging system is to exhaust the exhaust gas from the engine**, and then push the turbine blades to rotate, and then inhale the air, and then compress the air, and finally compress the compressed air into the cylinder, and at the same time, because the air intake is large, the oil intake should also increase, otherwise the temperature will be too high and burn out the engine, the principle of the turbine is similar to the air compressor of the refrigerator.

The working principle of the exhaust gas turbocharger is to introduce the exhaust gas from the engine into the turbine, and use the energy of the exhaust gas to drive the turbine to rotate, thereby driving the compressor coaxial with the turbine to achieve pressurization.

Classification of turbocharging types.

Exhaust gas turbochargers can be divided into single-stage superchargers and two-stage compound superchargers according to the number of superchargers. Ordinary models commonly use a single-stage supercharging system, that is, an exhaust gas turbocharger;

The two-stage supercharging system uses two exhaust gas turbochargers, which are mainly used for large-displacement vehicle diesel engines. According to the different connection methods of the two turbochargers, the two-stage booster mode can be divided into two systems: in-line two-stage compound pressurization and parallel two-stage compound pressurization; Depending on the turbine used, exhaust gas turbochargers are available in two types: radial and axial.

Exhaust gas turbochargers are mainly composed of turbines and compressors. The exhaust gases from the engine are introduced into the turbine, and the energy of the exhaust gases is used to drive the turbine to rotate, thereby driving a compressor coaxial with the turbine to pressurize. The turbine air intake is connected to the engine exhaust manifold, which is connected to the exhaust pipe; The compressor inlet is connected to the air cleaner, and the exhaust is connected to the intake manifold.

The turbine wheel and the compressor wheel are rigidly connected by a supercharger shaft, which is called the supercharger rotor. The supercharger rotor is fixed in the supercharger when it rotates at high speed through a floating bearing, which can ensure that the frictional resistance torque is small. When the engine is working, the exhaust gas from the exhaust gas hits the turbine impeller at a certain angle at high speed, so that the supercharger rotor rotates at high speed (up to 20104 low rotation minutes).

The high-speed rotation of the compressor impeller increases the air pressure in the engine intake duct to achieve a pressurization effect. As a result, the air is subjected to greater pressure during the intake process, which allows more and denser air to enter the cylinder. In this way, the fuel can be burned more fully and the performance of the engine can be improved to a higher level.

On May 16, 2020, today Dabao shared with you the working principle of automotive turbochargers and the matters that need to be paid attention to in daily life.

A method of using the exhaust energy of an internal combustion engine to drive an exhaust gas turbocharger to achieve internal combustion engine supercharging。The exhaust gas turbocharger (referred to as the turbocharger) is composed of two main components: the turbine (see turbine) and the compressor (see compressor), as well as the shaft and bearings, lubrication system, cooling system, seals, heat insulation, etc.

The rotational speed is different. 1. Supercharged turbine: its speed changes with the speed of the engine, and there will be no supercharging lag, and the effect is excellent when the engine is running at low speed, but it is limited by the engine speed, and the engine will be under-pressurized at high speed.

2. Exhaust gas turbine: The turbocharger has an extremely high speed, and the increased pressure is several times higher than that of the mechanical supercharger. However, due to the inertia of the turbofan and the considerable resistance of the intermediate bearing, the turbofan speed will not increase at the same time when the exhaust gas suddenly increases, which is the turbo hysteresis.

Turbocharging uses the exhaust gases from the engine to drive the exhaust gas turbine, which drives the compressor impeller on the coaxial axis, so that it can press air directly into the cylinder. Its purpose is to increase the amount of air entering the cylinder, so that the fuel combustion is more sufficient, so as to improve the output power of the engine, which can play a role in energy saving and emission reduction.

The exhaust gas turbocharging system is to use the energy of the exhaust gas discharged by the engine to compress the fresh air entering the cylinder in advance, so that the engine can obtain higher charging efficiency, because the amount of compressed air is increased, it is allowed to inject more fuel, so that the engine can produce more power and have higher combustion efficiency under the condition of the same size, and reduce fuel consumption.

According to your description, the exhaust gas turbocharging system is to increase the amount of air intake to the engine.

Hello, the role of the exhaust gas turbocharging system is to increase the air intake of the engine.

It mainly uses the exhaust gas energy of the engine to drive the turbocharger turbine, and drives the compressor impeller on the coaxial to rotate, compressing the air and feeding it into the engine cylinder. Since the exhaust gas turbocharger is driven by exhaust energy, there is no mechanical transmission connection between it and the engine, which makes it mechanically efficient.

Better. At the same time, it does not require a complex transmission mechanism, and through continuous technology accumulation, the turbo hysteresis of traditional exhaust gas turbochargers has been well controlled. Therefore, it has become the most widely used engine supercharging device at present.

The disadvantage of exhaust gas turbochargers is that the power output of the engine before it is supercharged is higher than that of a naturally aspirated engine of the same displacement.

Poor, and the high temperature exhaust gas will subject the turbine and the casing to quite high temperatures.

The power output of the engine before it is not supercharged is worse than that of a naturally aspirated engine of the same displacement, and the high exhaust gases subject the turbine and the casing to quite high temperatures.

Hello, the characteristics are to increase the engine power by increasing the engine intake pressure, using the exhaust to drive the turbo increaser impeller, compressing the intake air pressure pump I hope you can, thank you.

1.The supercharger is only connected to the engine by gas lines and has no mechanical transmission, so the supercharger method has a simple structure and does not need to consume power. 2.

With a small increase in engine weight and volume, the engine structure can easily increase the power by 20%-50% without major changes. 3.Due to the exhaust gas turbocharging ** part of the energy, so the supercharged engine economy has also been significantly improved, coupled with the relative reduction of mechanical loss and heat dissipation loss, improve the mechanical efficiency and thermal efficiency of the engine, so that the engine turbocharged fuel consumption rate can be reduced by 5%-10%.

4.Turbocharged engines have a strong ability to adapt to altitude changes, so a car with exhaust gas turbocharging has a clear advantage in the highland area.

The technology is mature. In contrast to supercharged turbocharging, exhaust gas turbocharging does not consume engine kinetic energy.

Exhaust gas turbocharging currently generally uses small inertia turbos, and many brands can intervene at about 1500 rpm.

It has a cost advantage over mechanical pressurization.

Hope you can, thanks.

The so-called exhaust gas turbocharging is to use the exhaust gas discharged from the diesel engine to achieve the purpose of supercharging. The supercharger has no mechanical connection to the diesel engine, which is driven by a turbine driven by the exhaust gases of the diesel engine.

Under normal circumstances, the boost pressure (PK) can reach, and the boost pressure of the high-boost diesel engine can reach about it, and such a high boost pressure will also greatly increase the gas temperature, therefore, the higher pressurized diesel engine needs to add an air intercooler to cool the high-temperature compressed air.

According to the current corporate finance, according to the accrual system, the income of 1 million should be recognized if 1 million is worked, and the 400,000 yuan that is not received is recorded as accounts receivable.

If the cash basis is followed, only 600,000 yuan will be recognized if the income of 600,000 yuan is received.

Therefore, whether the 400,000 yuan that has not yet received is included in the income depends on whether you are treated on a cash basis or on an accrual basis.

Exhaust gas turbocharging system exhaust gas consists of exhaust gas turbocharger, internal combustion engine intake and exhaust system. The working principle is that the combustion gas of the internal combustion engine cannot fully expand to atmospheric pressure in the cylinder due to the limitation of the structural size. The exhaust gas turbocharging system efficiently transfers the exhaust energy to the turbine, so that the turbine can obtain high efficiency and at the same time facilitate the scavenging of the internal combustion engine cylinder.

According to the pressure condition in the exhaust pipe and the utilization of the energy carried by the exhaust letter rock, the exhaust gas turbocharging system is generally divided into two types: constant pressure boosting system and pulse boosting system.

1. Constant pressure booster system.

The exhaust from all cylinders of the internal combustion engine is fed through a thick exhaust manifold and then into the turbine. The exhaust main actually acts as a pressure regulator so that the gas pressure inside the main is basically constant. In this way, the turbine works under a steady air flow, so the turbine is more efficient.

However, when this system is adopted, the acceleration performance and low-load performance of the internal combustion engine are poor, so the constant pressure boosting system is only suitable for occasions with high pressurization and few changes in working conditions.

2. Pulse pressurization system.

This system is characterized by creating the greatest possible pressure pulsation in the exhaust pipe. For this purpose, the exhaust manifold was made thin and short, and the turbine was placed as close as possible to the cylinders of the combustion engine. The exhaust branches of several cylinders (usually two or three cylinders) that do not interfere with each other are connected to a single exhaust pipe, so that two slip or three continuous exhaust pulse waves are formed in each exhaust pipe.

The nozzle rings of the turbine are grouped by the number of exhaust pipes, so that they do not interfere with each other. The pulse boosting system can make full use of the exhaust energy and improve the performance of variable working conditions; However, the turbine works in a pulsating air flow state, so the turbine efficiency is low. In order to overcome the shortcomings of the two systems, pulse conversion systems and multi-pulse systems have been developed.

They are mostly used in diesel engines where the number of cylinders is not 3 times.

Photo by Zhang Guiye) @2019

The exhaust gas turbocharging system uses the power of the exhaust gas of the aging engine to boost the intake air and improve the charging efficiency of the engine. The turbocharging system compresses the intake air, increases the gas density, increases the amount of air entering the combustion chamber per intake stroke, and increases the base fuel supply, thereby improving combustion efficiency and fuel economy.

Schematic diagram of the exhaust gas turbocharging system.

Exhaust gas turbochargers are usually mounted on the intake manifold.

Exhaust gas turbocharger mounting location.

A turbocharger is mainly composed of a volute, a turbine, compressor blades, and a booster regulator.

The inlet of the volute is connected to the exhaust port of the engine, and the outlet is connected to the exhaust manipulator. The inlet of the compressor is connected to the inlet pipe behind the air filter, and the outlet is connected to the intake manifold or intake intercooler. The exhaust gases discharged from the engine drive the turbine to rotate, and the turbine drives the compressor blades to rotate, pressurize the intake air, and press it into the engine.

Turbocharger exterior.

Turbocharger profile.

The function of the turbine waste gas valve is to control the exhaust gas volume of the turbine impeller in the Sunzhen section, after the engine is turned off, the impeller is no longer needed to work at this time, and the opening of the wastegas bypass valve is conducive to the exhaust gas discharge in the engine.

The opening of the wastegate is controlled by the amount of vacuum in the turbocharger actuator, which works with the vacuum regulator according to the ECU signal. The wastegate opens in the following situations.

It should be easy to understand that the wastegate opens when the engine is turned off, and the purpose of the wastegate is to control the amount of exhaust gas passing through the turbine wheel. After the engine is turned off, the impeller is no longer required to work at this time, and opening the wastegate valve is conducive to the exhaust gas discharge in the engine.

Open the engine when it has just started and has not warmed up, as mentioned above, the wastegate valve is opened after the engine is turned off, which is conducive to exhaust emissions. In the same way, the reason why the engine speed of this car is so high is that the low engine temperature is not conducive to the combustion of the fuel mixture, and the three-way catalytic converter is not yet at the operating temperature, which is not conducive to monitoring fuel injection. At this time, increasing the engine speed can quickly increase the engine temperature.

The three-way catalytic converter is installed behind the turbocharger, and the wastegate valve is opened to increase the exhaust gas flow, which can reduce the warm-up time of the three-way catalytic converter.

At low loads, the wastegate valve is opened, and now the turbocharger produces exhaust gases only when the engine is running, which is already working. It's just that because the engine speed is not high, the energy that can be generated by its exhaust gas is relatively small. What's more, because there is no need for higher power output at low loads, if the wastegate valve is turned off, it means that the exhaust gas flow is blocked.

We know that the engine can draw in air because the negative pressure generated by the exhaust process of the combustion chamber is sucked into the air outside the engine compartment. However, if the exhaust gas is blocked, the exhaust gas is not discharged quickly, and back pressure will be generated, which will increase the pumping loss of the engine.

The common wastegate valve failure is the abnormal sound caused by loose wear, and the "bell" sound can only be heard at the moment of cold driving. This can only replace the turbocharged assembly, and this wastegate is not replaced separately.

Photo by Pacific Automobile Network Q&A).