When the turbocharger on the car is working, it has to withstand the impact of the high temperature and pressure exhaust gas from the engine. The speed of the turbine is generally more than tens of thousands of revolutions, up to 200,000 revolutions per minute, and the temperature is as high as 900 to 1000 ℃. .How does the supercharger lubricate and cool under such high operating temperature and speed? Let's talk about this problem.
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Moving parts of turbochargersThe moving parts of the turbocharger are also the core components-the turbine wheel, the compressor wheel and the rotor shaft. There are high-speed relative motions between the turbocharger housing and the turbocharger housing. This kind of speed cannot be withstood by ordinary bearings, so the bearing of the supercharger is a special floating bearing.It is actually a copper ring sleeved on the shaft and the shell, and there is a gap between the ring and the shaft and the ring and the bearing seat. When the engine is working, under the action of the oil pressure, a double oil film is formed in these parts, and the rotor actually floats on the oil film and rotates at a high speed.Due to the extremely high speed and extremely high temperature, this part also has extremely high requirements for lubrication and cooling.
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If the supercharger cannot get good lubrication and cooling, it will cause abnormal wear of the bearing, greatly shorten the service life of the bearing, increase the gap between the rotor and the housing, and part of the oil will enter the intake pipe or exhaust pipe from this part. , Resulting in serious oil burning failure.Poor heat dissipation can cause oil coking or cokingIn addition, poor heat dissipation can cause oil coking or carbon deposits, which will further damage the seal and lubrication of the turbocharger, aggravate the wear, and ultimately cause the turbocharger to leak oil or abnormal noise, and even jam in serious cases.Due to the special cooling and lubrication method of the turbocharger, there are also certain requirements on the use method of the turbocharger. For example, do not run at high speed immediately after starting a cold car, do not run at idle for a long time, and do not run after a long time with heavy load Turn off the engine immediately, don't blow the throttle before turning off, etc.
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In order to cool and lubricate the turbocharger, a special oil pipe is separated from the main oil passage of the engine lubrication system, so that the oil enters from the oil inlet above the supercharger intermediate body and flows out from the oil port below the intermediate body for lubrication and Cool the supercharger rotor and bearings.
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In order to ensure good lubrication and cooling effects, the flow rate of this part of the oil is very fast and the flow rate is relatively large. In order to cool the supercharger better, some current models have added a water-cooling device, which is driven by an electronic water pump. It can still work for a few minutes after the engine is turned off, and continue to dissipate heat from the supercharger to prevent the supercharger from overheating .Due to the special cooling and lubrication method of the turbocharger, there are also certain requirements on the use of the turbocharger. For example, do not run at high speed immediately after a cold car is started, do not run at idle for a long time, and do not run after a long period of heavy load operation. Turn off the engine immediately, don't blow the throttle before turning off, etc.
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In addition, the turbocharger must use high-quality fully synthetic engine oil to prevent poor lubrication or coking of the engine oil at high temperatures. When replacing the turbocharger, a certain amount of engine oil must be injected into the turbocharger to prevent the moment the engine is started. The turbocharger is not lubricated and burned.How does a turbocharger cool and lubricate?