Under China's stringent emission tax and environmental protection policies, more and more car companies choose to use small-displacement turbocharged engines, especially diesel engines, which are generally supercharged. Turbocharged engines have the advantages of strong power and low fuel consumption, but if used improperly, it is easy to cause early damage to the turbocharger. The cost of replacing the supercharger ranges from several thousand to several tens of thousands, which is a heavy burden for our car owners. So what behaviors do we damage the turbine most in daily use? How to use and maintain to effectively extend the service life of the turbocharger?
At the beginning, we need to understand the working principle of the turbocharger. It is driven by the exhaust gas pressure generated by the engine to drive the turbine in the turbine chamber. The turbine drives the coaxial impeller. The impeller is like an air compressor. The air sent from the air filter pipe pressurizes it into the cylinder. When the engine speed increases, the exhaust gas discharge speed and the turbine speed also increase simultaneously, and the impeller compresses more air into the cylinder. The increase in air pressure and density can burn more fuel. A corresponding increase in the amount of fuel can increase the engine's performance. Output Power. The conventional turbocharger can increase the intake pressure by (0.5~1.0) bar, and the explosive change can be 2.5 bar and above.
The working conditions of turbochargers are extremely harsh. Its working temperature is as high as 900 to 1000°C, and the speed is as high as 200,000 revolutions per minute. Such high working temperature and speed place extremely high requirements on the cooling, lubrication and dynamic balance of the turbocharger. 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 shaft and bearings. Therefore, anything that can destroy or reduce the lubrication and cooling effects may cause damage to the supercharger.
So what actions can damage the turbocharger? Let’s take a brief look at the following: 1. Start and drive vigorously: Turbocharged engines are less trouble-free than self-priming engines during cold start. At the beginning, the cooling oil can’t cool the turbocharger in time, which will cause vigorous driving. The temperature of the turbocharger is too high and the turbocharger is easily damaged. When starting, the car should drive slowly or wait for a while, so that the cooling system enters a normal cycle working state.
2. Long-time idle operation of the engine in place: The biggest problem of long-time idle operation of the engine in place is that it will cause poor heat dissipation of the supercharger, causing early wear of the turboshaft and floating bearings due to overheating; but this problem is not very important , And most people will not let the engine idling for a long time;
3. Turn off the engine immediately after running the engine at high load and high speed for a long time: the engine stops suddenly or shuts down immediately after running at high speed. Due to inertia, the turboshaft still needs to run at high speed (over 100,000 revolutions per minute) for a period of time, and the engine The lubrication system has stopped working and no longer supplies oil to the turbocharger. The turboshaft and floating bearings will overheat due to lack of oil lubrication, causing the turbocharger to burn out or wear early;
4. Boom the throttle before the engine is turned off: The reason for this is the same as the previous one. The reason why it is listed separately is that there are so-called old experience of some old drivers. Booming the throttle before the engine is turned off is good for the next start. This is effective for the old-fashioned carburetor engine, but for supercharged engines, it is harmless. Bouncing the throttle before stalling is a fatal blow to the turbocharger. This is really empiricism that kills people;
5. Use inferior or non-compliant engine oil: Because the turbocharger has a very high working temperature and a very high turbine shaft speed, the requirements for lubrication are also very high. Ordinary mineral engine oils are difficult to meet the requirements of use, especially It is some low-quality engine oil, which is prone to severe coking due to overheating, and insufficient lubrication strength, causing abnormal wear of the turbine bearing, resulting in damage to the turbocharger;
6. Leakage in the intake pipe or damage to the air filter: Our exhaust gas turbocharging is powered by the exhaust gas discharged from the engine, and then sucks the air from the air filter to compress it to our intake system! Therefore, if our air filter is too dirty, the high-speed rotating turbocharger blades will suck the dust and impurities in the air filter into the turbocharger. The quartz contained in the dust is very hard. High, quartz enters our turbocharger, it will damage the turbocharger, and also cause the wear of our cylinder. This is why the older our engine, the greater the noise.
In general, the main way to extend the service life of a supercharger is to always ensure that the supercharger has good lubrication and sufficient heat dissipation. Some turbocharged engines are now designed with delayed cooling technology, and a separate cooling system is set up. After the engine is turned off, the electronic water pump will continue to run for a period of time. It will not stop until the temperature of the supercharger drops, which can effectively prevent the increase in temperature. High temperature of the compressor. In order to prevent the engine from stalling after high-speed operation, some cars have specially designed a delayed flameout device called Turbo Timer, which can make the engine turn off when we turn off the ignition switch, remove the car key, and lock the door. It will automatically turn off after a few minutes of continuous operation, which can effectively protect the supercharger. Therefore, if used and maintained properly, the turbocharger can achieve the same life span as the engine.
Fengcheng Kaisida Foundry Co., Ltd.
