Best Review On Turbocharger Failure
In this post on Best Review On Turbocharger Failure, we will discuss the following topics
- Turbocharger problems
- Turbocharger Failure Symptoms
- Turbocharger failure causes
This post will be helpful to marine and Captive Diesel Power plant Engineers.
A turbocharger is the most integral unit on any Diesel Engine. Malfunctioning of Turbocharger can lead to the deterioration in the engine efficiency; will impact the smooth running of the Diesel engine. Components of the turbocharger are expensive. The cost of the turbocharger is the highest cost after the crankshaft of any diesel engine. We will discuss the problems, cause of problems, symptoms before failure, and the remedial actions to fix the issues.
Turbocharger Problems ( Best Review On Turbocharger Failure )
In my 45 years of experience in marine and captive diesel power plants, I have come across the following problems
- Bearing failures,
- Damage of compressor wheel
- Abnormal erosion on Nozzle rings
- Surging in Turbocharger
- Over speeding of Turbocharger
- Low discharge air pressure.
Bearing failures
Bearing failures during the operation can cause damage to the Turbo rotor, compressor wheel, Turbine blades, and damage to the turbocharger casing.
The causes of the Turbocharger bearing failure are listed below.
- Neglecting the bearing change schedule; – In one factory, there was a catastrophic failure in the Turbocharger. During the inspection observed that the customer did not change bearings as per schedule. Bearings were not available. The maintenance Engineer didn’t procure the bearings before the maintenance. The poor planning of the maintenance engineer has caused the heavy expenses to bring the Turbocharger back in service.
- Poor lubrication;- Using an inferior grade of oil for the bearing lubrication has been one of the reasons for failure in the Turbocharger with splash type bearing lubrication. In the Turbocharger with the pressure lubrication system, dirt in the oil was the reason. Dirt and carbon particles passing across the filters have clogged the oil holes. Blocking of the oil holes will make the Turbocharger starve with oil. The prolonged oil change schedules are the leading cause of such failures. In one case, I have observed the excessive blow-by from the cylinders have been polluting and causing the contamination of the engine lubricating oil. In one case, I have watched the oil diluted with the fuel. Dilution has been the cause for the reduction in oil viscosity. The less viscous oil at working temperature would cause the boundary lubrication of the bearings and, in the continuous operation, will cause the oil starvation.
The failure of the Lubrication pumps in the Turbocharger is also the most common cause of lubrication failure in the turbochargers.
- Overspeeding of Turbocharger;- In the engines with improper combustion of fuel, the after burning will cause the high exhaust temperature. High exhaust temperature will be the cause of high turbocharger speed. If the exhaust temperatures are unnoticed, it will result in overspeeding of the Turbocharger.
- Overheating of Turbocharger. In the Turbocharger with water cooling, the clogged water passages cause the overheating of the turbochargers. Overheating will cause the cracking of the turbocharger casing manufactured with the casting process. The external leak will not be dangerous as compared to the internal leaks. Internal leaks will cause the water to ingress in the lubricating oil.
Damage of compressor wheel ( Best Review On Turbocharger Failure )
In my experience, I have seen many compressor wheel damages. The reason for the compressor wheel damage is.
- Ingress of a foreign material; – if the environment is dusty or any foreign material traveling from the induction manifold will impinge on the blades of the compressor wheel rotating at high speed. Ingress of the foreign particle was the cause of compressor wheel damage in most of the cases.
- Many Turbochargers have failed due to the poor design of casing holding clamps. Breakage of the clamping cone was the main reason for the damage of compressor whee. Sudden damage was due to the compressor wheel rubbing with the casing. Failure of clamping device has been causing significant damage to the compressor wheel and rotor shaft.
- I have also seen the catastrophic failure has taken place immediately after the maintenance. Improper K clearance will cause such nature of problems.
Abnormal erosion on Nozzle rings (Best Review On Turbocharger Failure)
- Premature failure of nozzle rings has been due to the engines running with high sulfur fuel. High sulfur fuel causes erosion on the Nozzle ring blades. An increase in the exit area of blades has proved to be the reason for the decrease in engine efficiency.
- Improper combustion is also one of the most influential factors in accumulating the carbon deposits on the nozzle ring blades. The clogging of the blades will cause the surging in the Turbocharger. The clogged nozzle ring blades also cause an increase in high exhaust temperature.
- Valve burning and traveling off the burnt valve material with the exhaust were also reasons for the nozzle ring damage.
Surging in Turbocharger ( Best Review On Turbocharger Failure )
The main reason for the turbocharger surging has been found due to the exhaust valve wrong opening timing and the leakage due to the valve lid burning. Choking of the exhaust manifold or chimney is the second reason. Check for the proper sizing of the exhaust chimney diameter with minimum bends, and the choking in the waste heat recovery boiler and exhaust silencer.
The causes of surging
1. Excessive exhaust backpressure
2. Chocked scavenged ports
3. Excessive turbo outlet restriction
4. Fouled Nozzle ring blades
5. Leaky Exhaust valves
6. Misfiring in one or more cylinders
7. Fouled Compressor wheel Blades
8. Chocked Charge Air Cooler
9. Turbo outlet pressure leak
10. Erratic engine or engine control operation
11. Exhaust muffler filled with a large amount of water in it.
12. Sudden Load Change
13. Fire in Scavenge space or Exhaust Trucking
14. A collapsed air cleaner filter element.
15. Several cylinders were misfiring.
16. A badly worn fuel control linkage.
17. An improperly adjusted governor.
18. A worn governor actuator.
19. A voltage regulator with an intermittent output fault.
20. Damaged turbine and compressor blades on the turbo.
Low discharge air pressure (Best Review On Turbocharger Failure)
Reasons for the low discharge air pressure
- Low Turbocharger speed
- Fouled charge air cooler
- Insufficient cooling water for cooling the air in charge air cooler
- Damaged compressor wheel
- Leakage of air from the casing.
Selection and Matching Turbocharger to Large Propulsion Engine Performance
Best Review On Turbocharger Failure
The diesel engine is a compression-ignition internal combustion heat engine which can be operated in both the four- and two-stroke cycle. This high efficiency translates to good fuel economy and low greenhouse gas emissions.
Pressure charging is the process of force-feeding air into the combustion chamber of the diesel engine. All marine propulsion diesel engines have an air-charge system with an exhaust driven turbine. This is referred to as turbocharging. A modern turbocharger has simple, modular design, aimed at improving overall life cycle. Developments in turbocharger’s component design and manufacture all contribute to this goal.
The key design criteria include: -High specific flow rates -High efficiencies and reliability -Low noise emissions -Ease of maintenance and mounting -Long-service life When comparing similar rated engines, in terms of environmental protection, one fitted with a modern turbocharger will consume some 10-15% less fuel while reducing gaseous emissions by equally significant amounts. However it is not just in fuel efficiency where environmental protection benefits lie, in noise and vibration for example, modern turbocharger has succeeded in lowering noise emissions to less than at one meter distance and has improved vibration characteristics, by having kept the natural frequencies well above any exciting frequencies from the diesel engine.
In connection with turbocharger matching to marine propulsion diesel engine, years of experience have enabled makers of turbocharger to develop a simple, semi-empirical method for selecting the optimum turbocharger for any propulsion engine, turbocharging system, output data and ambient conditions, at low computation cost and with sufficient accuracy. The calculation of turbocharging system with pulsating admission of the turbine is based on an empirical ‘pulse factor’ and can thus be reduced to a simple computation of a system with ‘equivalent constant-pressure admission’ of the turbine. All the empirical characteristic variables are so defined that they can be determined from the usual, available numerical data from acceptance tests and turbocharger adaptation tests, and also by step-by-step computation of real working cycle.
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