DEL ARBITRAJE TRIBUTARIO

Exhaust gas temperature exceeds the normal value At the constant engine power load and speed:

High air suction temperature when operating without cooling purging air. Engine

Failure in fuel injection system. Turbocharger

Lack of air, for example contaminated filter. Contaminated compressor

Excess exhaust gas back pressure Turbine blade damage.

Purge air cooler

Contamination, lack of cooling water, excess cooling water temperature Insufficient ventilation.

Purge air below normal

At the same engine speed and normal condition at the air suction: Engine

Leaking air manifold.

Leaking gasline between engine and turbine Turbocharger

Incorrect reading of the pressure gauge or leakage at the inlet tube. Contaminated air filter resulting in pressure decrease.

Contaminated turbocharger Faulty labyrinth sealing Damaged turbine blade

Excess exhaust gas back pressure Purge air above normal

195

At the same engine speed and normal condition at the air suction: Engine

Failure in fuel injection system.

Engine power exceeds the estimated value. Turbocharger

Incorrect reading of the pressure gauge. Contaminated or partially clogged jet ring.

Turbocharger vibration

Significant rotor imbalance due to the compressor contamination or damaged turbine blades.

Bent shaft. Faulty bearing.

Wrong installation of bearings especially dampening packages. Abnormal noise during speeding-up or delay in pickup

Faulty bearings Rotor traction

Contaminated turbocharger Foreign object in turbocharger Leakage in body

Cracks

The cracks are the result of heat stresses caused for the irregular cooling, lack of water or due to the huge scale accumulation.

Gas side corrosion

Water accumulation in body.

Sulphuric corrosion induced erosion due to pulverized ash.

Water side corrosion

196

Using sea water for cooling.

Absence of corrosion prevention means at the water chamber inlets.

Slotted plates are installed in the water supply pipeline instead of water discharge lines (See Item 1.1).

Quick darkening of lube oil

Exhaust gas access the bearing housing. Sealing air channel X is clogged (drawing 1).

Mesh or slots of the equalizing channel Z are clogged. Air gap at the sealing bushing 505, 506 or 507 is too big. Lube oil loss

Air gap at the sealing bushing 505 or 506, 507 725 or 726 is too big.

Holes of equalizing channels Y or Z or holes on the sealing bushing 725 are clogged. Lock screws of the bearing housing cover are loose.

Some lock screws of the bearing housing cover are loose.

Moisture in turbocharger or bearing housings

Water drops or injection water penetrate channels Y and Z.

Water condensation in bearing housings at the high ambient humidity and low cooling water temperature and when the turbocharger is stopped.

Continuous turbocharger exhaust

197

Excessively high resistance at the air flow, for example, due to the contamination of air cooler, air filter or engine if abnormal sounds are detected in engine valve operation. If the reason of the continuous exhaust cannot be identified it is necessary to inform a manufacturer’s representative office.

Air cooler leakage

See the special instructions related to the air cooler.

3.1

Turbocharger shutting-down

In certain circumstances, for example, in the deep sea, it is necessary to keep the engine running even if the turbocharger is down. The following measures may be taken if there is a possibility to shut down the engine for some time.

3.1.0 Troubleshooting with site available spare parts

Take measures as according to the corresponding sections of this operational manual.

3.1.1 Rotor removal and closing unit installation (drawing

20 and Item 4.4)

Remove bearing assemblies form turbine and compressor ends as specified in Item 2.1.0.

Remove the rotor as specified in Item 2.1.1.

Close the holes with closing unit as shown at drawing 20.

Connect pull rods 9100 and 9101 to closing unit cover and fix to cover 9106 at the turbine end.

Screw nut 9107 until washers 9117 are tight.

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Install cover 9105 at the compressor end and screw nut 9107 until washers 9103 are tight.

Cooling water must be closed only in case if a serious leakage is detected at the gas side which is dangerous for the engine operation.

3.1.2 Interlocking unit installation

Supplied upon a special requisition (See Item 4.0).

For the engine running at the continuous load it is sufficient to interlock the engine at the compressor end according to Item 3.1.2.0.

For the engine running at the override mode in many cases the toque created by the exhaust gas at the turbine end is too high to secure the independent interlocking at the compressor end.

The following may be used as a guide: When the average effective pressure is not

less than 5 Bars (about 500 kN/m2 _{= 5 kg/cm}2_{) or when at the aforementioned}

pressure the one in cylinders acting to the corresponding turbine of the turbocharger

is approximately 5.7 Bars (about 570 kN/m2 _{= 5.7 kg/cm}2_{) it is necessary to interlock}

at the turbine end as well – See Item 3.1.2.1.

It is important to take bear in mind the recommendations of the engine manufacturer especially if they are related to such issues as air flow separation and power reduction of one or the other cylinder.

The cooling water is to be shut down only if a serious leakage is detected at the turbine body gas side which is dangerous for the engine operation.

If the gas continue to circulate through the turbine of the interlocked turbocharger it is important that the sufficient air pass by the compressor impeller thus assuring that the overheating is prevented. If the air is sucked through an inactive compressor that means that the cooling is secured.

If several turbochargers are connected to a single shared air manifold it is necessary to close the air discharge outlet of the interlocked turbocharger in order to prevent air leaking.

In this case, there should be an access providing the cooling air flow. This access must have at least the following dimension:

199

VTR 160 161 200 201 250 251 320 321 400 401 500 501 630 631 750 751 900 Ø 10mm 13mm 16mm 20mm 25mm 32mm 40mm 48mm 57mm

3.1.2.0 Compressor end interlocking (drawing 16, Item 4.0)

200