02 - michael petersen

7/29/2019 02 - Michael Petersen

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23.09.2010MAN Diesel & Turbo < 1 >

Nature of the maritime maintenance problem,

seen from an engine manufactures point of view.

Michael Petersen

Senior Manager

Engine Management / PrimeServ


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23.09.2010MAN Diesel & Turbo

Agenda

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Life cycle cost is the total costfrom design to disposal, theobjective of LCC is to choose themost cost effective approach, sothat the lowest long term cost ofownership is achieved!

Maintenance seen as a life cycle cost.

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Maintenance seen as a life cycle cost.

Procurement cost

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Procurement cost is widely usedas the primary (and sometimesonly) criterion for equipment,

spare parts or system selection(i.e. the cheaper the better).

However, the major costs lie inthe care and operation of

equipment during its life.


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CBOCondition Based Overhaul Strategy,

Largely extended Overhaul intervals.

Never touch a well running unit

Condition Based Overhaul (CBO)

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The Objective is:

Tankers and similar vessels

3 - 5 years operation without immobilisation, equal to

18 / 32,000 hours between major overhauls (dock todock)

Container, bulkers and similar vessels

Up to 5 years between major overhauls of bearings,turbochargers, pistons, cylinders and piston rings.


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Status

Major Overhauls / Inspections,which require immobilisation:

Bearings

Turbochargers

Cylinder units

Fuel pumps

Exhaust valves


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How to judge when overhaul is necessary?

2-stroke engine's can be inspected by open-up

the doors, go in, see, check and record.

In addition Bearing Wear Monitoring (BWM),

Main Bearing Temp. Monitoring (MBTM),Water in Oil Monitoring (WIOM) and

Liner Wall Temperature (LWT) systems are

essential tools

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Bearings, CBO overhaul / open-up criteria:

Main bearings should only be opened in case of alarm.

Check every 3 month:

Clearance and deflexion readings.

Bearing edges to be checked by wire-feeler formissing- or squeezed-out metal

All parts of the crank case to be checked for loose metal.

Con. rod- and x-head bearings:

Random open up inspection at the 5 year's docking,

and in case of external indications


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Modern MAN BW 2-stroke

engines are designed to

extended TBO by means of:

Slide fuel valves

Nimonic- or Dura spindles

W-seat

Oros combustion Chamber,

formed entirely in steel as a

result of

low positioned matingsurface

Low positioned ring packages

Heavy dutyring packages

Optimised liner temperature


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Nimonic spindle & W-seat,

S60MC, 25.500 service hrs

Dura Spindle & W-seat,

S60MC, 40.042 service hrs

(DuraSpindle seat welded on Nimonic spindle)



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Modern MAN BW 2-stroke

engines are designed to

extended TBO by means of:

Slide fuel valves

Nimonic- or Dura spindles

W-seat

Oros combustion Chamber,

formed entirely in steel as a

result of

low positioned matingsurface

Low positioned ring packages

Heavy dutyring packages

Optimised liner temperature


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When is piston overhaul needed?

Before piston burning reach 15

mm

Condition based piston overhaul


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Still rounding

Still rounding

Still rounding

Still roundingCBO example:

10K98MC-C, unit 7, 23,597 hours

without overhaul.

Note, visual good condition,

without being perfect.

Is it due for overhaul?

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Status

Fig. 3. Totally scuffed unit. Lubrication should beincreased to maximum until overhaul is convenientwith regard to the schedule of the ship. Due to thefriction heat developed, the piston rings get hardened,and the wear rate of the liner increases significantly.However, the hardening protects the rings, which iswhy the operation may be continued safely until nextconvenient port stay.

Fig. 4. Unit with micro-seizures on the top ring as aresult of metal-to-metal contact. Should be counter-acted by temporarily increased lubrication. It isimportant to lower the lubrication to normal as soonas the active mz-attack is stopped. Note that old, notactive, mz-marks remain visible long after the attackhas stopped and do not call for increased lubrication.

Fig. 5. Unit with 23,500 hours without piston overhaul.Note that most of the rounding is still intact, indicatingthat only of the wear potential is used. Further, themeasurements above from the same unit shows thatonly of the ring groove wear potential is used, andthe rate of burnings on the piston top is insignificant.Consequently, overhaul of that unit is not needed atthis stage.

Visual inspection of piston rings (cermet-alu coated top ring)



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Status

Fig. 6. Totally scuffed unit. Lubrication should beincreased to maximum until overhaul is convenientwith regard to the schedule of the ship. Due to thefriction heat developed, the piston rings get hardened,and the wear rate of the liner increases significantly.However, the hardening protects the rings, which is

why operation may be continued safely until nextconvenient port stay.

Fig. 7. Unit with micro-seizures on the top and bottomrings as a result of metal-to-metal contact. Should becounteracted by temporarily increased lubrication. Itis important to lower the lubrication to normal as soonas the active mz-atack is stopped. Note that old, notactive, mz-marks remain visible a long time and do

not call for increased lubrication.

Fig. 8. Unit running very well after 20,021 runninghours. Note that the last remains of the alu-coat arestill visible on the lower edge, indicating remainingrounding left. This means that the ring wear is lessthan 2 mm out of possible 3 mm. Consequently,many more hours are left from the point of view of

wear.

Visual inspection of piston r ings (all alu-coated)



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23.09.2010MAN Diesel & Turbo 22


Scuffingw

ear

Polishedw

ear

Adhesive

wear

Normalcorrosive


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Cylinder ConditionReport - la...


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4.8 mm

When is piston overhaul needed?

3 mm


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Cylinder Lubrication, latest experience


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Testing flat rate at 0.50 g/kWh abs.

8S60MC Car-carrierHigh topland pistonAlu-coated CPR piston ringsSlide fuel valve

Low cyl. oil dosages 0.50 g/kWh the last6,805h on 4 cylinders

Piston (number 1) never pulled (picture takenat 42,773 ring hours after running 0.55 g/kWh!)Piston number 1 has now just passed 50,000hours without overhaul.

Cylinder Lubrication, latest experience


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Overhaul Strategy on MAN B&W 2Stroke Engines :

Tankers:

9To limi t overhauls and inspections by means of extended engine monitoring

93 / 5 year overhaul intervals, to coincide with Class-Dockings, are presently possible

on engines with the newest design.

Container and Bulk Carriers:

9To limit overhauls / inspections by means of Condition Based Overhaul (CBO),

whereby the average TBO of the main components can be increased

up to 5 years.


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Overhaul Strategy on MAN B&W 2Stroke engines

9Expect all pistons to be fully reconditioned

by re-welding and re-chroming9 Heavy duty Piston Ring Packages

9Extended engine monitoring

9Intensified engine survey

(scavenge port inspections)


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Overhaul Strategy on MAN B&W 2Stroke engines

Quality requirements for significantly Extended TBO of the Cylinder Units:

9Sophisticated Piston Ring Packages require high manufacturing quality

9Recondit ioning of piston crowns requires high quality from an authorised work

shop

9The piston overhaul jobs require high quality, also regarding the reporting

9Intermediate inspections require qualified engineers and reporting


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Service Versus

Advantage of Maintenance contracts


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MAN Diesel

PrimeServ

Copenhagen

Spare

Parts

Upgrades

Special

Projects

Technical

Service

Diesel

Academy

Service Versus

Engine Management Concept

Advantage of Maintenance contracts.Engine Management Concept

Advantage of Maintenance contracts


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Advantage of Maintenance contracts.EMC overview

(1) MAN Diesel conducts the complete logistic works

Advantage of Maintenance contracts.


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Advantage of Maintenance contracts.Maintenance Schedule



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gMachinery Otimisation



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gEngine Performance

Action:

Observe any abnormality by daily checks of engine parameters.

Maintain full engine performance report twice every month

Evaluate all obtained engine data carefully and compare with earlier data / shop

test / sea trial data.

Benefits:

Safe and Reliable Engine.

Low Maintenances Cost.

Optimum Plant Economy


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Questions?

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