Turbocharger is a high-temperature environment in the Super high-speed rotating machinery, speed up its work 50 000 to 240000 r / min, such high-speed rotating machinery often due to improper installation and damage caused, enabling users suffered economic losses. China currently used by the supercharger whether domestically produced or imported, are often useful life of less than the expected useful life, the reasons for more than 90 per cent is due to improper installation. Serious overloading of vehicles or users to change their own supply of life is affected supercharger the main factors. This paper presents a supercharger in the use of some common faults and the reasons for.
1 turbocharger oil spills at both ends
Supercharger or both ends of a terminal oil spills, is the use of one of the most common fault. In theory, normal pressure to enter the intermediate oil in the face through the bearings, the oil has become zero, the natural downward by gravity only the return of the engine oil sump. But in normal working condition supercharger impeller round ends back at a certain gas pressure, it is not oil from the low pressure area to the flow of high pressure zone. Seal ring's main role is sealed compressor and turbine shell intermediate oil to gas leakage cavity, only in exceptional circumstances, to the role of oil from the seal. Nevertheless, if improperly used, in the following circumstances may cause oil spills at both ends of the supercharger.
1.1 long-term idling engine running
Prolonged idling engine running, turbocharger turbine impeller and the back wheel will have certain negative pressure, resulting in the middle of the oil leakage, it is in the pilot stage, experts have repeatedly carried out a special test The results, it should avoid prolonged idling engine running.
1.2 impeded oil return
As a result of the use of the oil pipeline to a road obstruction or deformation, resulting oil to the oil impeded, high oil pressure in the middle, along the rotor axial compressor oil flow out of both ends sealing ring caused oil spills. So frequently check back to the pipeline road is clear, guarantee the return to normal oil sump.
1.3 engine crankcase pressure too high
Crankcase pressure exceeding the prescribed emission values will supercharger Road tubing pressure to increase oil to poor sealing ring caused oil spills. To carry out regular checks crankcase ventilation state, as well as the exhaust pipe is clear. Steyr engine should pay extra attention to whether it is normal for oil and gas separator in order to prevent the crankshaft box-mixed gas pumped into the exhaust pipe and compressor cylinder, the engine burning oil caused the phenomenon.
1.4 blocked air filter
After long-term use of the engine, the air filter will filter because of excessive dust and cause obstruction, resulting in high suction inlet compressor impeller wheel back will be too high due to the vacuum sealing ring leakage , it is necessary for regular inspection and maintenance air filter, the filter is not obstruction, do not breakdown, the supply remained normal state.
1.5 sealing ring wear or failure
Long-term replacement of oil, the oil in too many impurities from the abrasive role, which exacerbated sealing ring wear, thinning, and gradually lose their sealing, closure of oil caused by oil spills. Refers to the so-called oil impurities greater than 0.02 mm in foreign particles, these particles can be random impurities oil into the oil-film bearings and shaft sealing ring and in the serious grinding rotating parts, heavier parts wear failure.
2 floating bearing wear
Floating bearing wear is a supercharger oil spill one of the most common fault. After the failure of such, the bearings and shaft gap between too much and film instability, capacity decreased, the rotor shaft vibration aggravated undermine balance. Too much sealed at both ends of the radius of rotation damage may be serious supercharger to the entire destruction. This failure primarily for the following reasons:
2.1 specification did not use pressurized oil
Turbocharged engines after the heat load and mechanical load substantial increase in the working conditions of a very high temperature, so that the oil temperature increases, the viscosity decreased capacity declined. Supercharger and the engine speed higher than the speed nearly 20 times, turbocharger bearings, the temperature is much higher than the temperature of the engine crankshaft. This requires high viscosity oil, to be capable of high-speed rotor load and high temperature, but also has good dispersion, oxidation resistance and wear resistance, and general it is very difficult to achieve this oil use requirements.
Pressurized oil in general on the basis of oil has been added to a variety of additives from a multi-grade oil. Has excellent dispersion, oxidation resistance, corrosion resistance and wear resistance, it is necessary instructions on the proper use of the specification pressurized oil.
2.2 cleanliness bad oil
As mentioned earlier, oil contains too many impurities will expedite the bearings and shaft wear and tear, often found in the maintenance of the engine oil sump black, thinning, and even Muddy to be black, such as oil continue to use cents Bearing no doubt will in a short time due to wear and tear scrapped.
Supercharger oil from the engine of the pump, pump if the machine does not work normal, resulting in insufficient supply or low oil pressure, as well as tubing into the road deformation, obstruction, the occurrence of cracks caused phenomena such as inadequate supply of oil, can the turbocharger bearings and shaft damage due to poor lubrication. Often found in the maintenance of bearings and shaft are some obvious signs of dry friction, will see serious burning blue phenomenon. Therefore, to carry out regular checks into the tubing Road, and remove problems.
Supercharger oil imports should be greater than 0.2 MPa pressure to ensure the supply of oil and rotating parts such as bearings normal lubrication. In addition turbocharger rotor inspection, if the axial gap too large, then the thrust bearing wear too large. If excessive radial clearance, the floating bearing wear too large.
3 compressor or turbine impeller damage
3.1 engine exhaust pipe of the metal into the
Supercharger in the normal high-speed operation, if the engine exhaust pipe from the nut, the screw type of metal, an inevitable result of the damage to turbine blades, turbine shell can be serious when Jipi. Similarly compressor impeller film encountered such a situation will be damaged. If the impeller damage to the film, then the rotor balancing immediately destroyed, and turbocharger rotor shaft vibration increased supercharger will not be able to continue to use, the maintenance department immediately sent to or replacement of the supercharger. If heard in the use of differences in response immediately stopped and inspected to prevent the compressor blade fragments falling into the engine cylinder, causing serious accidents.
3.2 did not require the use of air filter
In the desert areas or poor operating environment for use supercharged engine, the air filter fine dust or cracks in the pipe into the turbocharger, supercharger impeller can lead inlet wear the uniform of the leaves, supercharged The pressure lowering effect, could seriously undermine the balance of the rotor, air filter should be regular inspection and maintenance, the timely replacement filter, in order to reduce the occurrence of such failure.
3.3 does not promptly remove sludge
Supercharger after prolonged use, dust in the air with mist forming sludge, and gradually gathered in the shell imported supercharger access to the impeller housing and without gaps or leaves contact with the supercharger shell and friction , supercharger from the vibration of the rotor shaft, the shaft increased wear. Regular checks should be promptly removed sludge.
3.4 exhaust temperature is too high
The supercharger failure of the engine fuel system, such as supply delays, excessive supply, or exhaust nozzle Diyou phenomena such as gate leakage can lead to the exhaust temperature is too high, thereby enabling the import of the turbine blade Burning deformation. Exhaust temperature too high can make the turbine oil-sealed carbonation, and the turbine-bearing local overheating (check-pressure gas turbine bearings normal and the firing-bearing blue or black) and sealed bearings caused premature Failure.
Shedding 3.5 Nut
Nut in operation detached from the shaft skidded off the compressor impeller, smashed, damaged turbocharger scrapped. First, the failure of tightening torque nuts enough, and the second is not installed on the nut thread compound. Compressor impeller and rotor shaft gap is used with a certain amount of the nut torque will be fixed with its strict torque, torque shaft bending over to the General Assembly, resulting in reduced accuracy of the rotor shaft balance, vibration Supercharger too large, too small or torque on the plastic screw, nut will work in the loose and even damage to the impeller spondylolisthesis.
4 turbocharger the correct use
4.1 Information launched
Turbocharged engines idling necessary after the commencement of operation of 3 ~ 5 min. Supercharger for the engine oil supply from the machines, pumps, engine start, supercharger and machine pumps started at the same time, but because of supercharger and the oil pipeline between the oil pump for a long, and most supercharged The installation location is higher than the engine, oil supply will be a lag phenomenon. Idle operation, bearing load on the supercharger, oil and little effect on oil, but the engine started immediately after the high-speed full-throttle load, supercharger oil supply will lag due to poor lubrication caused damage.
4.2 correct downtime
Turbocharged engines idling downtime before running 3 to 5 min of downtime, because suddenly downtime, machine pumps stopped operating, no longer supply oil to the supercharger and turbocharger of the high speed rotor, in the role of inertia under section to rotation time to stop supercharger will be in short-term non-oil lubrication state vulnerable to the rotor shaft and bearing wear and damage. Since the turbocharger high thermal load, and the exhaust pipe heat conduction to the gas turbine and rotor shaft, the rotor shaft will immediately stop the formation of larger temperature gradient. In the absence of oil cycle circumstances stop suddenly, will be easily generated by the rotor shaft overheated thermal expansionʹrotor shaft and bearing killed.
In short, users must strictly in accordance with the requirements of Manual proper operation, as far as possible, to play the role of the three major lubricants (lubrication, decontamination, cooling), as far as possible avoid artificial, unnecessary damage faultʹsupercharger and scrapped, so as to ensure proper life supercharger.