The full name of turbofan engine is a kind of aircraft engine, which is developed from turbojet engine. Compared with turbojet, the main feature is that the area of the first-stage compressor is much larger, and it also acts as an air propeller (fan) to push back a part of the sucked air through the periphery of the jet engine. The part of the engine core through which air passes is called the internal duct, and the part outside the engine core through which only fan air passes is called the external duct. The turbofan engine is most suitable for the flight speed of 400 to 1000 km, so most aircraft engines now use turbofans as power sources.
The bypass ratio (also called bypass ratio) of turbofan engine is the ratio of the air mass that does not pass through the combustion chamber to the air mass that passes through the combustion chamber. A turbofan engine with a bypass ratio of zero is a turbojet engine. The early turbofan engines and turbofan engines used in modern fighters have low ductwork. For example, the world's first turbofan engine, Rolls-Royce Conway, has a bypass ratio of only 0.3. The bypass ratio of most modern civil aircraft engines is usually above 5. The turbofan engine with high bypass ratio consumes less fuel, but the thrust is equivalent to that of turbojet engine, and it is much quieter when running.
.. the birth of turbofan engine.
After World War II, with the passage of time and technological innovation, turbojet engines have been insufficient to meet the power demand of new aircraft. Especially the subsonic civil aircraft and large transport aircraft developed rapidly after World War II, the flight speed should reach high subsonic speed and the fuel consumption should be small, so the engine efficiency should be high. The efficiency of turbojet engine can no longer meet this demand, which shortens the range of the above aircraft. Therefore, for some time, there have been more and more large aircraft using turboprop engines. In fact, as early as 1930s, there were some rough early designs of jet engines with external bypass. In the 1940s and 1950s, early turbofan engines began to be tested. However, due to the very high requirements for the design and manufacture of fan blades. Therefore, it was not until the 1960s that people were able to manufacture fan blades that met the requirements of turbofan engines, thus opening the practical stage of turbofan engines. In 1950s, NACA (the predecessor of NASA) carried out very important scientific research on turbofan engine. 1955-56, the research results were transferred to General Electric Company (GE) for further development. GE successfully launched CJ805-23 turbofan engine at 1957, and then broke a lot of records of supersonic jet engine. But the earliest practical turbofan engine is Pratt &; Whitney JT3D turbofan engine. In fact, Pratt & Whitney started the turbofan engine development project later than GE. After learning the secret of GE's research and development of CJ805, they quickly stepped up their work and first launched the practical JT3D. 1960, rolls royce's "Conway" turbofan engine began to be adopted by Boeing 707 large long-range jet, becoming the first turbofan engine used by civil airliners. In 1960s, the large turbofan engines RB2 1 1-22B of rolls royce were adopted in Lockheed's Samsung passenger plane and Boeing's 747 Zhenbao passenger plane, which marked the full maturity of turbofan engines. Since then, turbojet engines have been quickly abandoned by the western civil aviation industry. Principle of turbofan jet engine The thrust of turboprop engine is limited, which affects the flight speed of aircraft. Therefore, it is necessary to improve the efficiency of jet engines. The efficiency of engine includes thermal efficiency and propulsion efficiency. The thermal efficiency can be improved by increasing the temperature of the gas in front of the turbine and the pressure increasing ratio of the compressor. Because high temperature, high density gas contains more energy. However, under the condition of constant flight speed, increasing the temperature in front of the turbine will naturally increase the exhaust speed. The gas with fast flow rate loses a lot of kinetic energy when it is discharged. Therefore, unilaterally increasing thermal power, that is, increasing the temperature in front of the turbine, will lead to a decline in propulsion efficiency. To improve engine efficiency in an all-round way, it is necessary to solve the contradiction between thermal efficiency and propulsion efficiency. The beauty of turbofan engine lies in increasing the temperature in front of the turbine without increasing the exhaust speed. The structure of turbofan engine is actually to add several stages of turbines in front of turbojet engine, and these turbines drive a certain number of fans. Like a common jet engine, a part of the airflow inhaled by the fan is sent to the compressor (the term is called "inner duct"), and the other part is directly discharged from the periphery of the turbojet engine casing ("outer duct"). Therefore, the gas energy of turbofan engine is divided into two kinds of exhaust streams generated by fan and combustion chamber respectively. At this time, in order to improve the thermal efficiency and increase the temperature before the turbine, more gas energy can be transferred to the external pipeline through the fan by appropriate turbine structure and increasing the diameter of the fan, thus avoiding a significant increase in exhaust speed. In this way, thermal efficiency and propulsion efficiency are balanced, and the efficiency of the engine is greatly improved. High efficiency means low fuel consumption and longer range.
Edit the advantages and disadvantages of this turbofan engine.
As mentioned above, the turbofan engine has high efficiency, low fuel consumption and long flight range.
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turbojet
This is a turbine engine. It is characterized by completely relying on airflow to generate thrust. Usually used as power for high-speed aircraft. Fuel consumption is higher than that of turbofan engine. There are two types of turbojet engines: centrifugal and axial. Centrifugal type was patented by British Sir Frank Whittle in 1930, but it was not until 194 1 that an airplane equipped with this engine went to heaven for the first time. It did not participate in World War II, but was born in Germany, and participated in 1945 as the first practical jet fighter Me-262. Compared with centrifugal turbojet engine, axial flow has the advantages of small cross section and high compression ratio. Today's turbojet engines are all axial flow.
Principle and working mode of. ...
Turbojet engine adopts jet propulsion, which avoids the inherent weakness of rocket and ramjet engine. Because the turbine-driven compressor is used, the engine also has enough pressure to generate strong thrust at low speed. The turbojet engine works according to the "duty cycle". It sucks air from the atmosphere, and after compression and heating, the air with energy and momentum is discharged from the propulsion nozzle at a speed as high as 2000 ft/s (6 10 m/s) or about 1400 mph (2253 km/h). When the high-speed jet flows out of the engine, it drives the compressor and turbine to continue to rotate at the same time, maintaining the "working cycle". The mechanical layout of turbine engine is relatively simple, because it only contains two main rotating parts, namely compressor and turbine, and one or several combustion chambers. However, not all aspects of this engine have this simplicity, because thermal and aerodynamic problems are more complicated. These problems are caused by the high working temperature of the combustion chamber and turbine, the changing airflow through the compressor and turbine blades, and the design of the exhaust system that exhausts the gas and forms a propulsion jet.
When the aircraft speed is lower than about 450 mph (724 km/h), the efficiency of pure jet engine is lower than that of propeller engine, because its propulsion efficiency depends largely on its flight speed; Therefore, pure turbojet engine is most suitable for higher flight speed. However, due to the airflow disturbance caused by the high tip speed of the propeller, the efficiency of the propeller drops rapidly above 350 mph (563 km/h). These characteristics make some medium-speed aircraft use a combination of propeller and gas turbine engine-turboprop engine, rather than a simple turbojet device.
The advantages of propeller/turbine combination are replaced by the introduction of internal and external ducted engines, ducted fan engines and propeller fan engines to some extent. These engines have larger flow and lower jet speed than pure jet engines, so their propulsion efficiency is equivalent to that of turboprop engines and exceeds that of pure jet engines.
Turbojet/ramjet engine is a combination of turbojet engine (usually used at various speeds below Mach 3) and ramjet engine, which has good performance at high Mach number. The engine is surrounded by a duct with an adjustable air inlet at the front end and an afterburner with an adjustable nozzle at the rear end. When taking off and accelerating, and under the flight condition of Mach number 3, the engine adopts the working mode of conventional turbojet engine; When the aircraft accelerates above Mach number 3, its turbojet mechanism is closed, and the air in the air passage bypasses the compressor with the help of guide vanes and directly flows into the afterburner, which becomes the combustion chamber of the ramjet. This engine is suitable for aircraft that require high-speed flight and maintain high Mach number cruise. Under these conditions, the engine works as a ramjet engine.
Turbine/rocket engine is similar to turbine/ramjet engine in structure, and an important difference is that it has its own oxygen for combustion. This engine has a low-pressure compressor driven by a multi-stage turbine, and the power to drive the turbine is generated by burning fuel and liquid oxygen in the rocket combustion chamber. Because the gas temperature can be as high as 3500 degrees, it is necessary to inject additional fuel into the combustion chamber for cooling before the gas enters the turbine. Then, this oil-rich mixture (gas) is diluted by air from the compressor, and the remaining fuel is burned in the conventional afterburner system. Although this engine is smaller and lighter than the turbo/ramjet engine, it consumes more fuel. This trend makes it more suitable for interceptors or spacecraft launch vehicles. These aircraft require high-altitude and high-speed performance, usually require high acceleration performance, and do not need long battery life.
..... structure
admitting port
The main structure of axial-flow turbojet engine is shown in the figure. Air enters the inlet first, because the flight state of the aircraft is changing, and the inlet needs to ensure that the air can finally enter the next structure smoothly: the compressor. The main function of the air inlet is to adjust the air to the state that the engine can run normally before entering the compressor. When flying at supersonic speed, both the nose and the inlet will produce shock waves, and the air pressure will increase after passing through the shock waves, so the inlet can play a certain role in precompression, but the improper position of the shock waves will cause uneven local pressure and even damage the compressor. Therefore, there is a shock wave adjusting cone at the inlet of supersonic aircraft, and the position of shock wave is adjusted according to airspeed.
Aircraft with air intake on both sides or belly will be affected by the boundary layer (or boundary layer) of the fuselage because the inlet is close to the fuselage, and a boundary layer adjustment device will be installed. The so-called boundary layer refers to a layer of air flowing close to the surface of the fuselage. Its velocity is much lower than the surrounding air, but its static pressure is higher than the surrounding air, forming a pressure gradient. Because of its low energy, it is not suitable for entering the engine and needs to be eliminated. When the aircraft has a certain angle of attack (AOA), due to the change of pressure gradient, boundary layer separation will occur at the part where the pressure gradient increases (such as leeward side), that is, the boundary layer that was originally close to the fuselage will suddenly separate at a certain point and form turbulence. Turbulence is relative to laminar flow, which is simply an irregular moving fluid. Strictly speaking, all flows are turbulent. At present, the mechanism and simulation of turbulence are not clear. But that doesn't mean turbulence is not good. In many parts of the engine, such as the combustion process, we should make full use of turbulence.
compressor
The compressor consists of stator blades and rotor blades. A pair of stator blades and rotor blades is called the first stage. The stator is fixed on the engine frame, and the rotor is connected with the turbine through the rotor shaft. The active turbojet engine is generally an 8- 12 compressor. The more stages, the greater the pressure. When the fighter suddenly performs a high-g maneuver, the air pressure flowing into the front stage of the compressor will drop sharply, and the pressure in the rear stage will be very high. At this time, the high-pressure air in the rear stage will expand reversely, and the engine is extremely unstable, which is called "surge" in engineering. This is the most fatal accident of the engine, which is likely to cause shutdown or even structural damage. There are several ways to prevent "surge" Experience shows that surge mostly occurs between the 5th and 6th stages of the compressor, and a bleed ring is set in the second interval to release the pressure in time when the pressure is abnormal, so as to avoid surge. Or the rotor shaft is made into two concentric hollow cylinders, which are respectively connected with the front-stage low-pressure compressor and the turbine, and the rear-stage high-pressure compressor and the other turbine. The two rotor groups are independent of each other, so the speed can be automatically adjusted when the pressure is abnormal, and surge can also be avoided.
Combustion chamber and turbine
Air enters the combustion chamber after being compressed by the compressor, and is mixed with kerosene for combustion, and expands to do work; And then flows through the turbine to drive the turbine to rotate at high speed. Because the turbine and the compressor rotor are connected on the same shaft, the rotation speed of the compressor and the turbine is the same. Finally, the high-temperature and high-speed gas is ejected through the nozzle, and the power is provided through the reaction. At first, the combustion chamber was several small cylindrical combustion chambers, which were juxtaposed in a ring around the rotor shaft. Each cylinder is not sealed, but a hole is opened in a proper place, so that the whole combustion chamber is connected. Later, it developed into a compact annular combustion chamber, but the overall fluid environment was not as good as that of a cylindrical combustion chamber, and a combined combustion chamber combining the advantages of the two appeared.
Steam turbines always work under extreme conditions, and there are extremely strict requirements for their materials and manufacturing technology. At present, powder metallurgy hollow blades are mostly cast in one piece, that is, all blades and disks are cast at one time. Compared with the early days, each blade and disc were cast separately and then connected by tenon, which saved a lot of connection quality. The manufacturing materials are mostly high temperature resistant alloy materials, and the hollow blades can be cooled by cold air. The new engine developed for the fourth generation fighter will be equipped with ceramic powder metallurgy blades with more outstanding high temperature performance. These measures are aimed at improving one of the most important parameters of turbojet engine: the pre-turbine temperature. High pre-swirl temperature means high efficiency and high power.
Nozzle and afterburner
The shape and structure of the nozzle (or nozzle) determine the airflow state that is finally eliminated. Early low-speed engines used simple convergent nozzles to improve speed. According to Newton's third law, the greater the ejection velocity of gas, the greater the reaction force the aircraft will get. However, the growth rate of this method is limited, because the final airflow speed will reach the speed of sound, and then there will be a shock wave to stop the increase of gas speed. Supersonic jets can be obtained by using convergent-divergent nozzles (also known as Laval nozzles). The maneuverability of the aircraft mainly comes from the aerodynamic force provided by the wing surface. When the maneuverability is high, the thrust of the jet can be directly used. There are two schemes in history, that is, installing gas control surface at the nozzle or directly using deflectable nozzle (also known as thrust vector nozzle or vector thrust nozzle), and the latter has entered the practical application stage. The superb maneuverability of the famous Russian Su -30 and Su -37 fighters benefited from the AL-3 1 thrust vector engine of Rurika Design Bureau. The representative of the rudder is the American X-3 1 technical verification machine.
After the high-temperature gas passes through the turbine, it still contains some oxygen that is not consumed in time. If kerosene is continuously injected into this gas, it can still burn and generate additional thrust. Therefore, some high-performance fighter engines add afterburner (or afterburner) behind the turbine to achieve the purpose of greatly improving the engine thrust in a short time. Generally speaking, afterburner can increase the maximum thrust by 50% in a short time, but the fuel consumption is amazing. Generally, afterburner is only used for take-off or fierce air combat, and cannot be used for long-term supersonic cruise.
..... use
Turbojet engines are suitable for a wide range of navigation, from low-altitude subsonic to high-altitude supersonic aircraft. MiG -25 is a legendary fighter in the former Soviet Union. It used the turbojet engine of Liurika Design Bureau as the power, and once set a fighter speed record of Mach 3.3 and a ceiling record of 37,250 meters. This record is unlikely to be broken for some time.
Compared with turbofan engine, turbojet engine has poor fuel economy, but its high-speed performance is better than turbofan engine, especially at high altitude and high speed.
turbine engine
1. What is turbocharging?
First, let's figure out what turbocharging is. The English name of turbocharging is Turbo. Generally speaking, if we see Turbo or T at the rear of a car, it means that the engine used in this car is a turbocharged engine. I believe you have seen many such models on the road, such as Audi A6 1.8T, Passat 1.8T, Bora 1.8T and so on.
Turbocharging kit
The main function of turbocharging is to increase the air intake of the engine, thus improving the power and torque of the engine and making the car more dynamic. After the engine is equipped with turbocharger, its maximum power can be increased by 40% or even higher than that without turbocharger. This means that the same engine can generate more power after being supercharged. Take our most common 1.8T turbocharged engine as an example. After supercharging, the power can reach the level of 2.4L engine, but the fuel consumption is not much higher than that of 1.8 engine. Another level is to improve fuel economy and reduce exhaust emissions.
However, after supercharging, the pressure and temperature of the engine increase greatly, so the life of the engine will be shorter than that of the engine with the same displacement and without supercharging, and the mechanical properties and lubrication performance will be affected, which also limits the application of turbocharging technology in the engine to some extent.
Second, the principle of turbocharging
The earliest turbochargers were used in sports cars or formula racing cars, which made the engine gain more power in those racing competitions with limited engine displacement.
Red is high-temperature waste gas, and blue is fresh air.
As we all know, the engine generates electricity by burning the fuel in the cylinder. Because the fuel input is limited by the amount of air sucked into the cylinder, the power generated by the engine is also limited. If the running performance of the engine is in the best state, increasing the output power can only increase the fuel quantity by compressing more air into the cylinder, thus improving the combustion function. Therefore, under the current technical conditions, the turbocharger is the only mechanical device that can increase the output power of the engine without changing the working efficiency.
The turbocharging device we usually talk about is actually an air compressor, which increases the air intake of the engine by compressing air. Generally speaking, turbocharging is to use the inertia impulse of the exhaust gas discharged by the engine to drive the turbine in the turbine room, and the turbine drives the coaxial impeller to pressurize the air sent by the air cleaner pipeline into the cylinder. When the engine speed increases, the exhaust gas discharge speed increases synchronously with the turbine speed, and the impeller compresses more air into the cylinder. With the increase of air pressure and density, more fuel can be burned. The output power of the engine can be increased by increasing the fuel quantity and adjusting the engine speed accordingly.
You may think that the turbocharger is complicated, but it is not. Turbocharging device is mainly composed of turbine chamber and supercharger. First, the air inlet of the turbine chamber is connected with the exhaust manifold of the engine, and the air outlet is connected with the exhaust pipe. Then the air inlet of the supercharger is connected with the air cleaner pipeline, and the air outlet is connected with the air inlet manifold. Finally, the turbine and the impeller are respectively installed in the turbine chamber and the supercharger, and are coaxially and rigidly connected. Such an integrated turbocharging device is completed, and your engine is "overclocked" like a computer CPU.
Third, the types of engine pressurization
1. Mechanical supercharging system: This device is installed on the engine and connected with the crankshaft of the engine through a belt. It gets power from the output shaft of the engine and drives the rotor of the supercharger to rotate, thus blowing the supercharged air into the intake manifold. Its advantage is that the turbine speed is the same as the engine speed, so there is no lag phenomenon and the power output is very smooth. But because it is installed in the rotating shaft of the engine, it still consumes some power, and the effect of supercharging is not high.
2. Air wave pressurization system: air is compressed by pulse air wave of high-pressure waste gas. This system has good supercharging performance and acceleration performance, but the whole device is huge and not suitable for installation in small cars.
3. Exhaust gas turbocharging system: This is the most common turbocharging device in our daily life. The turbocharger has no mechanical connection with the engine, but is actually an air compressor, which increases the intake air by compressing air. It uses the inertia impulse of the exhaust gas discharged by the engine to push the turbine in the turbine chamber, and the turbine drives the coaxial impeller, which pressurizes the air sent by the air cleaner pipeline and sends it to the cylinder. When the engine speed increases, the exhaust speed and the wheel speed also increase synchronously, and the impeller compresses more air into the cylinder. With the increase of air pressure and density, more fuel can be burned, and accordingly, the output power of the engine can be increased by increasing the fuel quantity. Generally speaking, after installing the exhaust gas turbocharger, the engine power and torque will be increased by 20%-30%. However, exhaust gas turbocharging technology also has its own points that must be paid attention to, that is, the pump wheel and turbine are connected by a shaft, that is, the rotor. The exhaust gas from the engine drives the pump wheel, which drives the turbine to rotate, and the turbine rotates to pressurize the air intake system. The supercharger is installed on the exhaust side of the engine, so the working temperature of the supercharger is very high, and the rotating speed of the supercharger rotor is very high, which can reach hundreds of thousands of revolutions per minute. Such a high speed and temperature make the ordinary mechanical needle roller or ball bearing unable to work for the rotor, so the turbocharger generally adopts full floating bearing, which is lubricated by oil and cooled by coolant.
4. Compound supercharging system: that is, exhaust gas turbocharging and mechanical supercharging are used together. This device is widely used in high-power diesel engines, with high engine output power, low fuel consumption rate and low noise, but its structure is too complicated, its technical content is high, and it is difficult to maintain and popularize.
Fourth, the shortcomings of turbocharged engines
It is true that turbocharging can improve the engine power, but it also has many shortcomings, the most obvious of which is the lag of power output response. Let's take a look at the working principle of turbocharging, that is, due to the inertia of the impeller, the reaction to the sudden change of the throttle is slow, that is to say, there is a time difference between your big foot stepping on the throttle and the rotation of the impeller, and more air is pushed into the engine to gain greater power, which is not short. Generally speaking, improved turbocharging also takes at least 2 seconds to increase or decrease the power output of the engine. If you want to accelerate suddenly, you will feel that you can't accelerate instantly.
With the development of technology, although various manufacturers who use turbochargers are improving the technology of turbochargers, because of the design principle, driving a turbocharger car is still a little surprising compared with driving a large-displacement car. For example, if we buy a 1.8T turbocharged car, the acceleration in actual driving is definitely not as good as 2.4L, but as long as we wait for the waiting period, the power of 1.8T will come up, so if you pursue the feeling of driving, the turbocharged engine is not suitable for you. Turbocharging will be especially useful if you are running at high speed or something.
If your car often drives in the city, you really need to consider whether it needs turbocharging, because the turbine is not always started. In fact, in daily driving, turbocharging is rarely started or even used, which has an impact on the daily performance of turbocharged engines. Take the turbocharging of Subaru (Fuji) impreza as an example. Its starting time is about 3500 rpm, and the most obvious power output point is about 4000 rpm. At this time, there will be a feeling of secondary acceleration, which lasts until 6000 rpm or even higher. Generally speaking, when we are driving in urban areas, the shift is only between 2000 and 3000, and the estimated speed of the fifth gear is 120, which means that unless you deliberately stay in the low gear, the turbocharging with the speed not exceeding 120 km/h cannot be started at all. Without the start of turbocharging, your 1.8T is actually just a car with 1.8 power, and the power of 2.4 can only be your psychological function.
In addition, turbocharging has maintenance problems. Take Bora's 1.8T as an example, the turbine will be replaced about 60,000 kilometers. Although the frequency is not too much, after all, it invisibly adds a maintenance fee to your car, which is particularly noteworthy for car owners whose economic environment is not particularly good.
Verb (abbreviation for verb) The use of turbocharged engines
The turbocharger uses the exhaust gas from the engine to drive the turbine. No matter how advanced, it is still a set of mechanical devices. Because it often works at high speed and high temperature, the exhaust gas turbine end temperature of the turbocharger is above 600 degrees, and the rotating speed of the turbocharger is also very high. Therefore, in order to ensure the normal operation of the turbocharger, it is very important to use and maintain it correctly. Mainly should follow the following methods:
1. Don't slam on the accelerator after the car engine starts. You should rest for three minutes first. This is to increase the temperature of the engine oil, improve the fluidity and make the turbocharger fully lubricated. Then you can increase the engine speed and start driving. This is especially important in winter, and it takes at least five minutes to warm up the car.
2. After the engine runs at high speed for a long time, it cannot be turned off immediately. The reason is that when the engine is working, part of the engine oil is supplied to the turbocharger rotor bearing for lubrication and cooling. After the running engine stops suddenly, the oil pressure drops to zero rapidly, the oil lubrication will be interrupted, and the heat inside the turbocharger cannot be taken away by the oil. At this time, the high temperature of the turbine part of the turbocharger will be transferred to the middle, and the heat in the bearing support shell cannot be taken away quickly, while the turbocharger rotor is still rotating at high speed under the action of inertia. This will lead to "jamming" between the rotating shaft and the shaft sleeve of the turbocharger, and damage the bearing and shaft. In addition, after the engine is suddenly turned off, the temperature of the exhaust manifold is very high at this time, and its heat will be absorbed into the turbocharger housing, and the engine oil stranded in the turbocharger will be boiled into carbon deposit. When this carbon deposit accumulates more and more, it will block the oil inlet, lead to the lack of oil in the shaft sleeve and accelerate the wear between the turbine shaft and the shaft sleeve. Therefore, the engine should be idling for three minutes before flameout to reduce the rotor speed of turbocharger. In addition, it is worth noting that turbocharged engines are not suitable for long-term idle running, and should generally be kept within 10 minutes.
3. Pay attention to the choice of engine oil. Due to the function of turbocharger, the quality and volume of air entering the combustion chamber are greatly improved, and the engine structure is more compact and reasonable. The higher compression ratio makes the engine work harder. The machining accuracy is also higher, and the assembly technical requirements are stricter. All these determine the high temperature, high speed, high power, high torque and low emission characteristics of turbocharged engine. At the same time, it also determines that the internal parts of the engine should bear higher temperature and greater impact, extrusion and shear force. Therefore, when selecting engine oil for turbocharged vehicles, its particularity should be considered. The engine oil used must have good wear resistance and high temperature resistance, and a lubricating oil film block with high oil film strength and stability should be established. Synthetic engine oil or semi-synthetic engine oil can just meet this requirement, so in addition to the engine oil specified by the original factory, it is best to use high-quality lubricating oil such as synthetic engine oil and semi-synthetic engine oil.
4. The oil and filter must be kept clean to prevent impurities from entering, because the fit clearance between the rotating shaft and the shaft sleeve of the turbocharger is very small. If the lubricating ability of the oil decreases, the turbocharger will be scrapped prematurely.
5, need to clean the air filter on time, to prevent impurities such as dust from entering the high-speed rotating compressor impeller, leading to unstable speed or aggravating the wear of the shaft sleeve and seal.
6. Be sure to check whether the sealing ring of turbocharger is sealed. Because if the sealing ring is not sealed, the exhaust gas will enter the engine lubrication system through the sealing ring, making the oil dirty and the crankcase pressure rising rapidly. In addition, when the engine is running at low speed, the engine oil will also be discharged from the exhaust pipe through the sealing ring or enter the combustion chamber for combustion, resulting in excessive consumption of engine oil and "burning engine oil".
7. The turbocharger should always check whether there is abnormal sound or vibration, and whether the lubricating oil pipes and joints are leaking.
8. The precision of turbocharger rotor bearing is very high, and the working environment of maintenance and installation is very harsh. Therefore, when the turbocharger fails or is damaged, it should be repaired at the designated maintenance station instead of the ordinary repair shop.