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Different brands of exhaust gas turbochargers are widely used in various large and medium-sized diesel trucks, flatbed trucks, dump trucks, and various construction machinery. They make the diesel engine significantly increase the power and increase the torque under the condition of constant structure size, while reducing the fuel consumption and reducing the exhaust pollution, especially in the plateau region. 
In the course of work, the turbocharger rotates at a speed of up to tens of thousands of revolutions per minute, and is operated under high exhaust temperatures for a long period of time, so its working conditions are harsh. In use, the above-mentioned vehicles have experienced different degrees of power reduction and fuel consumption caused by improper use of a supercharger, which has led to a substantial reduction in operating efficiency and economic efficiency. The causes of the common failures of diesel exhaust turbochargers and preventive measures are as follows:
1, the correct use of diesel
The first is the quality grade of the diesel engine oil. For diesel engines with low supercharged pressure, diesel engine oil of no less than CC grade should be used. For diesel engines with medium supercharger, diesel engine oil of no less than CD level should be used. Followed by the diesel engine viscosity grade, should be based on the temperature conditions, the wear conditions of the machine and other suitable viscosity grade.
The cleanliness of diesel engine oil is again because the coordination of the rotor shaft of the exhaust gas turbocharger and its bearing (shaft sleeve) is more precise. If the diesel engine oil is dirty or deteriorates, impurities or abrasive particles will be carried into the supercharger. The wear of the bearing is accelerated, and the weight of the lubricant film cannot be formed so that the rotor shaft and the bearing are seized. Therefore, be sure to keep the oil clean, clean the oil filter regularly, and replace the oil that has deteriorated in time.
2, the correct cold start method
After starting the vehicle, the diesel engine should be allowed to idle for a few minutes (depending on the engine temperature and ambient temperature), the standby oil reaches a certain temperature and pressure, the flow performance is improved, and the supercharger bearing is fully lubricated before it can increase the rotation speed. Driving or investing in construction work is especially important when outside temperatures are low.
For vehicles with a long parking time (for example, more than a few days), the booster inlet pipe connector should be released before starting, and the appropriate amount of engine oil with the same oil number as the oil pan should be filled into the oil inlet port to prevent poor lubrication during start-up. Ablate the rotor shaft.
3, the correct method of flameout
If the diesel engine is running at a high speed, if it suddenly shuts off, the oil in the exhaust gas turbocharger will immediately stop circulating due to the oil pump stalling. However, the rotor shaft of the supercharger is still rotating at high speed due to inertia, which is easy to cause Cut off the oil and burn it with its bearings.
In addition, the diesel engine with a load running, the exhaust manifold temperature is high, if a sudden stop, the heat will be transferred to the turbocharger shell, the engine oil has been stopped flowing fry carbon deposition. When the carbon deposit builds up, it will also block the oil inlet, leading to bearing oil shortage. Even if the oil inlet is not blocked, the carbon deposit will accelerate the bearing wear.
To do this, make sure that the diesel engine gradually reduces the load before the flameout, and finally idle for a suitable period of time until the speed of the rotor shaft of the turbocharger decreases and the temperature of the oil drops to stop. After the flameout, the turbocharger rotor shaft will continue to idle for a certain period of time, and sometimes a slight "click" may be heard.
4, the correct operation of the diesel engine in operation
1 Maintain the normal working temperature of the supercharger. When the supercharger is working, the normal temperature of the turbine shell is about 400°C, and the temperature of the compressor shell is not suitable for hot. In use, if the diesel fuel supply is too large, the fuel supply time is too late, and the long-term overload operation or Frequent thumping of the throttle will overheat the supercharger due to high exhaust temperatures, which will increase wear and tear.
If the turbine end oil seal fails, the oil in the supercharger enters the turbine shell and is discharged together with the high-temperature exhaust gas discharged from the cylinder, resulting in excessive consumption of engine oil and smoke emission in the exhaust pipe. If the oil seal at the compressor end fails, the oil in the supercharger will break into the compressor casing, and as the intake air is sucked into the cylinder to burn, it also causes excessive consumption of engine oil and smoke in the exhaust, which also increases the amount of carbon deposit in the cylinder.
2 Maintain normal lubrication system oil pressure. When the diesel engine is in operation, when the oil pressure of the lubrication system is lower than 015 MPa, it should be stopped and checked to prevent the turbocharger from being poorly lubricated and ablating the rotor shaft and the bearing. The oil pressure must not be too high to prevent the oil from entering the turbine room or the compressor room. The idle time of the diesel engine at low speed should not be too long to prevent the oil pressure from being too low and the supercharger to have poor lubrication.
3 Strengthen the air filter maintenance work. To make the diesel injected into the cylinder fully burned, a large amount of clean air must be supplied. After the supercharger is installed on the diesel engine, the fuel supply of the fuel injection pump is adjusted accordingly. If the air filter is blocked and the intake air is insufficient, the diesel engine power will be significantly reduced. Therefore, we must strengthen the maintenance of the air filter to ensure its normal working condition.
In addition, if the filter element breaks or the seal agglomerate fails to age, the booster will rotate at a slower speed due to the ingress of lime sand, resulting in increased noise and increased wear of the bearing, oil seal, and air seal assembly. It should be noted that maintenance of the air filter must not allow hard objects to fall into the air intake pipe, so as to avoid breaking the impeller or breaking the rotor shaft after inhaling the supercharger, it may cause a cylinder accident.
5, the correct maintenance of turbocharger
During use, the bolts between the three housings of the supercharger should be inspected and tightened to eliminate oil leakage and air leakage. For every 500-1000 hours of diesel engine operation, the supercharger should be removed to check if the rotor is flexible. There is no carbon deposition on the inlet and outlet ports of the supercharger, and it is carefully cleaned to ensure that the engine oil is unobstructed. Scrape the tiny dust deposited on the throat of the compressor, clean the scale, air seal and oil chamber in the water layer of the middle shell, remove the carbon deposits in the turbine, nozzle ring and turbine shell, and clean the air seals and oil seals. And check the damage and replace it if necessary.
When disassembling the supercharger, because the turbine shell and the compressor shell are all thin-walled castings, do not knock and hit. If necessary, tap the wooden hammer to tap. Do not use iron to prevent breaking. The assembly of the rotor shaft assembly must be in place according to the original mark, so as not to affect its dynamic balance. Keep it clean during assembly and do not allow debris to fall into the interior of the housing or piping. The oil inlet and outlet of the middle shell should be installed vertically. The outlet pipe should be gradually bent and connected to the crankcase after being taken out from the supercharger. There should be no “dead bend†in the middle to prevent the oil from flowing and the oil flowing to the engine. Turbine or compressor room leaks.