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Operating Faults in Turbochargers

written by: guruvignesh • edited by: Lamar Stonecypher • updated: 5/24/2011

The turbocharger is vital and sensitive equipment used to compress intake air by using the heat energy from the waste exhaust gas of diesel engine. This article deals with various operating faults of the turbocharger during operation, the causes, and remedies for operational troubles.

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    Introduction

    The turbocharger, which is also known as a forced induction system, is used to increase the efficiency of the engine by supplying the compressed air at certain pressure to the engine. The turbocharger converts the waste heat from the exhaust gas (heat energy) into the mechanical energy to drive the compressor. A turbocharger may create some faults due to its continuous operation at high temperature of exhaust gas. This article deals with various operating faults of the turbocharger during operation, location of those faults, causes, and the remedies for the operational troubles. How to locate and troubleshoot the turbocharger failure isexplained in this article. Operating faults like exhaust gas temperature too high, charge air pressure too low, charge air pressure too high, vibration of turbocharger, noise on running down, reluctant starting, and constant surging of turbocharger are explained in this article.

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    Exhaust Gas Temperature too High

    Causes and Remedies:

    1. There may be faults in engine fuel injection system (i.e.) more fuel injection .The remedy is to adjust correct fuel timing according to manufacturer.
    2. Insufficient air in the combustion chamber for combustion. Turbocharger filter may get chocked or blocked. For this, clean the filter of the turbocharger.
    3. Compressor or turbine of turbocharger may get contaminated. The remedy is to clean the compressor side and turbine side of turbocharger.
    4. Exhaust gas back pressure too high. This may be due to high carbon deposits in exhaust gas duct and in nozzle ring. The remedy is to clean the carbon deposits in the exhaust gas duct.
    5. Turbine blade is damaged or eroded. In case the turbine is eroded the only remedy is to replace the turbine blades and rotor of turbocharger.
    6. Cover ring may be eroded. The remedy is to clean it if possible or to replace it.
    7. Charge air cooler may be dirty due to carbon deposits in tube fins due leaky labyrinth seal in turbocharger. The remedy is to clean the copper fins around the tubes.
    8. Insufficient cooling water through charge air cooler. The cooling water inlet valve may be throttled by mistake. The remedy is to open the valve fully (if it is throttled) or to top off the cooling water system.
    9. Charge air cooler cooling water inlet temperature is too high. Check the temperature of cooling eater and clean the cooling system.
    10. Insufficient ventilation around the turbocharger. The remedy is to improve the ventilation by running a blower or ventilation fan in an enclosed atmosphere.

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    Turbocharger Worked Under High Exhaust Temperature

    Turbocharger Worked Under High Exhaust TemperatureExhaust side of turbocharger
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    Charge Air Pressure too Low

    Causes and Remedies:

    • Leakage in the exhaust gas duct between engine and the turbine. The remedy is to locate the leak and to repair it.
    • Fuel injection may be incorrectly adjusted. The remedy is to adjust the fuel injection timing correctly.
    • Manometer indication may be defective. Check the correct functioning of manometer and if it is found defective replace the manometer.
    • Leak in the line to the manometer. The remedy is to repair the leak.
    • Dirt in the air filter causing pressure drop. Clean the filter.
    • Dirt in compressor and turbine of turbocharger. Clean compressor side and turbine.
    • Labyrinth seal leaking or damaged. Consult the service station for replacement.
    • Turbine blades and compressor impeller damaged. Replace the rotor. While replacing the rotor, ensure that the rotor is dynamically and statically balanced.
    • Nozzle ring damaged. The remedy is to replace it.
    • Cover ring eroded. The remedy is to replace it.
    • Exhaust gas back pressure too high. The remedy is to clean the exhaust gas silencer.
    • Charge air cooler is dirty. This can be found by the pressure drop across the charge air cooler. The remedy is to clean the charge air cooler.
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    Charge Air Pressure is too high

    Causes and Remedies:

    • The main reason is that engine performance is higher than normal. The remedy is to check the engine performance and reduce it to normal.
    • Fuel injection system incorrectly adjusted. The remedy is to adjust it correctly.
    • Manometer indication may be incorrect. Check the correct functioning of manometer and if it is found defective replace it.
    • Nozzle ring is dirty or partly obstructed. The remedy is to clean it.
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    Vibration of Turbocharger

    Causes and Remedies:

    • Rotor of the turbocharger is unbalanced due to heavy contamination of compressor side and turbine blades. The remedy is to clean the compressor side and turbine side either by water washing or by dry cleaning and it is better to call service station if the vibration is abnormal.
    • Turbine blades or binding wire in turbine blades is damaged. Replace it.
    • One of the turbine blades may be broken or eroded too much which may cause the rotor to become unbalanced due to variation of centrifugal force acting in various blades during operation. The remedy is to remove the blades which are broken and also remove the opposite blades to the broken blades thereby equalizing the centrifugal force acting on the rotor.
    • The bearing may be misaligned. Seek possible cause or replace the bearing.
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    Noise on Running Down, Time too Short, and Reluctant Starting

    Causes and Remedies:

    • Bearing is damaged. The remedy is to replace the bearing with the manufacturer.
    • Rotor is rubbing. Call service station personnel if it unable to find the fault.
    • Dirt in turbocharger. Clean it either by dry cleaning or by water washing.
    • The labyrinth seal is damaged. This is a whistling sound and is more specific than the remaining sounds. If you hear this sound call the service station to repair labyrinth seal.

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    Constant Surging of the Turbocharger

    Causes and Remedies:

    • Increased flow resistance due to dirt in the charge air cooler or heavy deposits of dirt in the compressor and turbine blades. The remedy is to clean both the compressor side and turbine side of the turbocharger either by using dry cleaning methods or by water washing (wet cleaning).
    • Defective check valves in a two stroke engine. The remedy is to replace the valves.
    • Exhaust gas pressure increased after the turbine because the exhaust gas silencer is dirty. The remedy is to clean it.