The turbine turbocharger is a machine which revolves at a high speed in high temperature. Its revolution may reach 50000-150000 rpm. Such high speed machinery requires high standard of processing, assembling and also installation and use.According to inquiry and analysis, over 90% of the malfunction was caused by the incorrect use or the self-malfunction of the engine so far. The common malfunction is the oil leakage, abrasion and damage of parts.
I. Oil leakage
Oil leakage at one end or both ends of the turbocharger is one of the most common malfunctions. Main reasons are as following.
1.Engine idling revolves for a long time. Long-time idling of engine produces a certain amount of negative pressure on the turbine and the back of the impeller wheel. Thus, the engine oil in the bearing housing leaks to the outside. This is the results that the experts got from the item experiments.
2.Return of oil is obstructed. This is caused by the deformation or block of the oil return pipe or the excessive pressure of engine crankcase during working. It also leads to the excessive high pressure of oil in the bearing housing. The oil will then move along the rotor shaft to both ends. This may squeeze out the sealed ring which bringing about oil leakage.
3.The air filter is blocked. The core of the air filter may be blocked because of accumulating dust. This leads to the excessive high air inlet negative pressure of air-compressor. Oil leaks at the hermetic sealing ring at the back of the impeller wheel because of high negative pressure.
4.The abrasion or ineffective of the hermetic sealing ring. Do not replace engine oil for a long time leads to too many impurities in engine oil. This causes aggravating abrasion of the hermetic sealing ring. It loses the function of seal of gas and oil, therefore oil leakage occurs.
Abrasion of journal bearings, rotor shafts and impellers are also common malfunctions. The gap between bearing and the shaft is too large when abrasion is grave. The dynamic balance of the rotor shaft system is destroyed. It leads to the damage of seal and aggravated vibration. Even worse, the impeller may bump the housing. It may even leads to the damage of the entire turbocharger. The main reasons of these malfunctions are as following.
1.Engine oil is unqualified. Did not use engine oil according to the requirement or cleanness of engine oil was insufficient.Both the working rotation rate and temperature are very high, therefore it demands for high quality of engine oil. Forbid using normal oil because of cheap and convenient.Replace engine oil and oil filter as they request in time as well.
2. Dry rubbing occurs because of lack of oil.Too low pressure, deformation and blockage of oil inlet etc. may lead to deficiency of fuel supply. Speeding up and adding load immediately after starting the engine, or speeding up and reducing the speed urgently will also bring about dry rubbing.
3. Inefficiency of air filtration. If you did not maintain and replace air filter in time as request, leak of air in the air inlet pipe may cause the inefficiency of air filtration. Therefore tiny sand and dust may enter which may cause abrasion.
4.The greasy filth is not eliminated in time. There are dust and oil fog in the air which can form greasy filth. After the turbocharger uses for a period of time, greasy filth will form on the impeller gradually. This destroys the dynamic balance of the rotor shaft system, and brings about vibration and abrasion.
III. Damage of spare parts
Breakdown of spare parts of the turbocharger is mainly the breakdown of impeller, dehiscence of housing, damage caused by burning and pulling and broken of rotor shaft and bearing. Besides oil leakage and abrasion mentioned above which caused these damage, there are also some other reasons as following.
1. Sundries get in the turbocharger. When the turbocharger is working in a regular high speed, if there is anything hard like nuts or screws, or something soft like rubber, cloth or paper gets into it, it is inevitable to destroy the turbine or air-compressor impeller blade. More serious, it may damage the turbine housing or air-compressor housing, and even break the shaft.
2. The temperature of air outlet is too high. Overloading, change presumptuously or do not adjust the property of the fuel supply, malfunction of fuel system of engine and air leakage as request by the consumers may be result in excessive high temperature of air outlet. Thus, it may burn off the turbine blade. It may lead to overheat of the bearing at the end of the turbine and the sealed ring at the same time.This makes the inefficiency of sealing up, burning and breaking down of the rotor shaft and bearing. More serious, it may even bring about dehiscence of the turbine housing.
3.Dynamic balance is destroyed.Since abrasion, dirt, too loosening or too tight of the impeller clamp nut and some other factors, the dynamic balance may be destroyed. Then it may lead to serious vibration of turbocharger, and damage parts.
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