Propulsion Large Containership

8/13/2019 Propulsion Large Containership

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Contents

Containership Propulsion - beyond Post-Panamax

P a g e

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Programme Development . . . . . . . . . . . . . . . . . . . . . . . . . .

Propulsion Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12,000 teu co ntainer vess el . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

P ropeller(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Main engines for a 12,000 teu conta iner vess el . . . . . . . . . . . . . .

Design Aspects of Large MC Engines . . . . . . . . . . . . . . . . . . . . . .

Alpha lubrica tors a nd lube oil co nsumption . . . . . . . . . . . . . . . . .

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12


2/11

Introduction

C ontainerisation continues to grow as it

has done for a long time. While the en-

tire world merchant fleet grew by only

1% in 1998, the containership fleet ex-

panded by more than 10% , and this

continuous growth has also led to the

development of verylarge containerships.

The term very large containership it-

self has been constantly redefined over

the last decade.

Tenyears ago, a 4,500 teu containership

represented the edge of the available

technology whereas today vessels

approaching twice that capacityare a

reality.

Specialists are debating where this

continuous increase in size is going to

stop, and some say that the maximum

capacity is likelyto be 11,000 teu because

of Suez regulations on maximum beam

and draught, and the wish for a reason-able deadweight/teu ratio.

As main engine designers, we are obvi-

ously following the development closely

in order for us to have the optimum main

engines available for present and future

container vessels.

Engine ProgrammeDevelopment

The M C engine programme has now

been in the market for 18 years, thus

it is a fully mature range of engines

covering a unit power span of 2,400

to more than 93,000 bhp. T hrough-

out the years new models have been

added and existing models upgraded

both in terms of design features and

power. Figure 1 shows the most impor-

tant steps taken, and Figure 2 shows the

present M C engine programme.

It is a well-known fact that the M C en-

gines have sold well throughout their en-

tire lifetime, actually to an extent where

our engines have become the industry

standard in a very large number of ship

types. T he most significant new addition

of engines has been the launch in 1996

3

Containership Propulsion beyond Post-Panamax

1981 L35M C introduced

1982 Full L-M C programme

1984 L-M C upgraded

1985 L42M C introduced

1986 K -M C introduced

S-M C introduced

L-M C upgraded

1987 S26M C introduced

1988 K -M C -C introduced

1991 M C programme upgraded

K and L-M C

S-M C

1992 S26M C and L35M C upgraded

1993 S35M C and S90M C introduced

K 90M C/M C -C upgraded

1994 S42M C introduced

1994 K 98M C-C introduced

1995 K 80M C-C upgraded

1996 L70M C upgraded1996 S70M C -C , S60M C -C , S50M C -C

and S46M C -C introduced

1996 S80M C upgraded

1997 L80M C upgraded

K 98M C introduced

1998 S80M C -C , S90M C -C ,

L90M C -C introduced

S35M C upgraded

1999 S42M C upgraded

mep = mean effective pressure C m = mean piston speed

M k mep Cm

bar m/s

7.2

7.2

7.6

8.2

8.0

8.0

8.2

8.0

8.0

8.3

8.0

8.28.5

8.3

8.0

8.0

8.3

8.1

8.2

8.0

1 15.0

2 16.2

2 16.2

16.2

17.0

3 16.2

16.8

16.2

5 18.0

6 18.0

18.5

6 18.0

6 18.5

6 18.2

6 18.0

6 18.019.0

19.0

19.0

6 18.0

6 18.2

19.0

7 19.1

7 19.5

Fig. 1: The MC p rogramme development


3/11

of the S46-50-60-70M C -C engines

and, in 1998, of the S80 S/L90M C -Cengines.

Figure 3 shows references for these

so-called compact engines and clearly

spells out that they are well accepted

by the marine market.

In Figure 4 the total M C engine references

can be seen.

Notable in this respect is also that

electronically controlled versions of the

7S60M C -C , designated 7S60M E-C ,have been chosen as prime movers in

a series of VLC Cs, withtwo main engines

in each vessel.

4

250

210

173

S26M C

L35M C

S35M C

L42M C176

136

129

S42M C

S46M C -C

L50M C148

S50M C127

S50M C -C127L60M C123

S60MC105

S60M C -C105

108

91 S70M C

91 S70M C -C

93 L80M C

104 K 80M C -C

79

76

S80MC

S80M C -C

104 K 90M C -C

K90M C

S90M C -C

L90M C -C

94

76

83

104

94

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000

r/min

kW

L70M C

K 98MC -C

K98M C

Fig. 2: The 1999 MC engine programme

Number of engines

Total: 84,198,306 bhp ~61,927,854 kWTotal

Type

98

90

80

70

60

50

46

42

35

26

O n order or delivered In service

0

187 135

445 394

724 618

1,442 1,284

1,197 1,018

34 16

204 182

961 844

171 158

5,385 4,649

20

Fig. 4: List of reference, all MC types,

as at 1999.10.01

Number of engines

Total: 3,146,840 bhp ~ 2,314,501 kW

5 0

15

37 12

101 50

34 16

Total 192 82

Type

S90M C -C

S70M C -C

S60M C -C

S50M C -C

S46M C -C

O n order or delivered In service

4

Fig. 3: List of reference, S-MC-C, as at

1999.10.01


4/11

Propulsion Aspects

In 1994 and 1997 we introduced the

K 98M C-C and K 98M C engines to cater

for the power requirements of large

container ships. T he main data of these

engines are shown in Figure 5.

As mentioned in the introduction, the

future points towards containerships

even larger than those being considered

large today.

Figure 6 is an attempt to quantify the

propulsion power required for such

vessels.

As can be seen, the power requirement

for the fastest of the 10-12,000 teu

vessels is beyond what can be covered

today even by our largest unit, the

12K98M C developing 93,360 bhp at

94 r/min, but engineswith more cylinders

are feasible.

14 and 16-cylinder versions can also

be built, thereby expanding the power

range up to some 125,000 bhp. Such

engineswould be available as both tradi-

tional in-line engines and V-type engines.

Although the latter form has not yet

been realised, we have investigated

this cylinder configuration in greatdetail, and a large number of patents

for innovative and exciting inventions

are pending. Among the advantages

offered by the V-type concept, com-

pared to the in-line version, are a 15

per cent weight reduction and a tre-

mendous length saving.

T he intriguing question in our opinion,

however, is whether single propellers

can be designed and built to absorb

such powers, or whether the tendency

would be towardstwin propellers/twin

engines.

To start from the (maybe) very top of

future capacity expectations, we have

made a feasibilitystudyof the propulsion

machinery for a 12,000 teu container

vessel.

12,000 teu container vessel

A 12,000 teu container vessel will need

other dimensions than have been used

for the Panamax and Post-Panamax

container vessels built in the last few

decades.

5

K98MCPower/cylinder

Speed

M ean effective pressure

Stroke

Bore

Stroke/bore ratio

M ean piston speed

SFOC

C ylinders

K98MC-CPower/cylinder

Speed

M ean effective pressure

Stroke

Bore

Stroke/bore ratio

M ean piston speed

SFOC

C ylinders

5,720 kW

7,780 bhp94 r/min

18.2 bar

2,660 mm

980 mm

2.7

8.3 m/s

126 g/bhph

171 g/kWh

6-12

5,710 kW

7,760 bhp

104 r/min

18.2 bar

2,400 mm

980 mm

2.45

8.3 m/s

126 g/bhph

171 g/kWh

6-12

Fig. 5: K98MC/MC-C, cross section and main data


5/11

The length, breadth and draught of the

ship will have to be increased signifi-cantly in order to accommodate a load

capacity of 12,000 teu. An increase of

length, breadth and draught will not

only influence the hull design, but will

also require that harbours and con-

tainer cranes are prepared for the new

era of container vessels.

It may be necessary to have up to 22

containers abreast on the deck in orderto facilitate the mentioned load capa-

city and keep the length and draught of

the container vessel within reason. The

expected dimensions of a 12,000 teu

container vessel, based on 22 contain-

ers abreast, are shown in the table.

Length on

waterline

LWL 385.0 m

Length between

perpendiculars

LPP 375.0 m

Breadth on

waterline

BWL 55.0 m

Design draught D 13.5 m

Displacement 175,000 m3

Propeller(s)

As mentioned previously, the capability

of one propeller to absorb the main en-

gine power, and generate the required

propulsion thrust at a reasonable effi-

ciency, will be an important issue when

discussing the propulsion of very large

container vessels.

It may be expected that the propeller

will have to be designed to absorb

more than 100,000 bhp to make the

servicespeed of a 12,000 teu container

vessel exceed 24.0 knots.

P ropulsion power of this magnitude

on a single shaft has not so far been

used on commercial vessels, and will

necessitate an appropriate fixed-pitch

propeller design that can deliver the

propulsion thrust.

Any reduction in propeller efficiency as

a result of a single propeller operating

at high load can open the door for

twin-screw container vessels. A vessel

equipped with two propellers should

preferably be designed as a twin-skeg

hull, since this solution will provide the

best overall propulsion efficiency ac-

cording to available theory on the sub-

ject. O utlines with K98M C and K 90M C

type engines installed in a twin-skeg

hull are shown in Figure 7.

The future of container vessels withtwo propellers will depend on the pos-

sibilities of an appropriate design of the

ships hull, and whether the ships

resistance and the water flow for the

6

Service speed (knots)0

20,000

40,000

60,000

80,000

100,000

120,000

23.0 24.0 25.0 26.0 27.0

SMC R (kW)12,000 T EU10,000 T EU

8,000 TEU6,000 TEU4,000 TEU

Fig. 6 : Propu lsion power fo r large container vessels

K90M C

55.0 m

K98M C

Twin-skeg c onta iner vess el

Waterline

Fig. 7: Out lines of K98MC and K90MC engines installed in a twin-skeg hull


6/11

propellers can be kept at levels that

can match the state-of-the-art for

single-propeller ships.

In theory, the open-water propeller effi-

ciency for a twin-screw installation can

be improved by up to 5% -points when

using a larger total propeller disc area,

fewer blades, etc. T his corresponds to

an approximately 8% saving in propul-

sion power if the resistance of the ship,

wake field and thrust deduction factor

of the twin-skeg hull can be kept atapproximately the same level as for an

ordinary hull with one propeller.

The available documentation and test

results for container vessels are still

scarce, but the information available

from the model tests on VLC C , U LC C ,

R o-Ro and ferries with twin-skeg hull

and twin propellers indicates that the

advantage in reduced propulsion power

requirement for these types of ship may

be up to 5-8% .

A 12,000 teu container vessel with two

engines and two propellers, including

the necessary auxiliary systems and

modification of the hull, will without

doubt be more expensive in first cost

than a single-propeller container vessel.

Therefore, in order for the twin-screw

container vessel to be an attractive op-

tion, the increase in first cost must be

compensated by lower operating costs

within a reasonable time frame.

Margins

The specified M aximum C ontinuous

R ating (M C R ) of the main engines de-

pends not only on the results obtained

from the model test/power prediction or

extrapolation of actual trial results, but

also on the margins that the shipyard

choosesto include in the dimensioning of

the propulsion system. The reasons for,

and the appropriate size of, sea margin,

engine margin and light running margin

are described in the following.

Sea margin (SM)The results from modeltestsare normallybased on clean hull and calm weather

conditions. Therefore, it is recommend-

able to add a sea margin to compensate

for the prevailing weather conditions

or any increased power requirement

due to deterioration of hull or propel-

ler(s).

The sea margin for Panamax and

Post-Panamax container vessels has

been in the range of 20-25% and oc-

casionally up to 30% . T he sea margin

for a 12,000 teu container vessel can

be kept at this level, since its sensitiv-

ity to changes in weather conditions,

approximate service speed and hullform will be similar to those of the

Panamax and Post-Panamax con-

tainer vessels.

Engine op erat ion m a rgin (EM)The Continuous Service Rating (C SR )

is normally set at 85% -90% of the

main engine specified M C R . T his

corresponds to an engine operation

margin of 10-15% of the specified

M C R power. An engine operation mar-

gin is included to provide an additional

power margin that can be utilised tocatch up with delays in departure etc.

M oreover, the Specific Fuel O il Con-

sumption is approximately 2-3% lower

at 85-90% of specified M C R than at

100% of specified M C R .

Light running margin (LR)The performance of the propeller, i.e.

absorbed power at a given propeller

speed, is influenced by the advance

speed of the water to the propeller

and, subsequently, by the increased

resistance of the hull at heavy weather

and/or fouled hull conditions. T his phe-

nomenon is also described as a heavy

running propeller.

It is recommendable during the design

phase to include a light running margin

(revolution margin) between the theo-

retical propeller curve through the en-gines specified M C R point and the

actual layout curve for the propeller at

calm weather and clean hull conditions.

A light running margin of 5-7% is

appropriate for a single-screw con-

tainer vessel. The light running margin

for a container vesselwith two fixed-pitch

propellerscould be increased somewhat

to compensate for the special running

conditionswhenonepropeller is blocked

and the otherpropeller is in operation.

Main engines for a 12,000 teucontainer vessel

The appropriate choice of main engine

and expected specified M C R at service

speeds of 23.0, 24.0, 25.0 and 26.0

knots are shown in the table below.

7

Service speed Hull with one propeller Hull with two propellers

23.0 knots Specified M C R

86,600 bhp x 104.0 r/minAppropriate engine:

1 x 11/12K 98M C -C

Specified M C R

2 x (39,900 bhp x 94.0 r/min)Appropriate engines:

2 x 7K90M C


97,500 bhp x 104.0 r/min

Appropriate engine:

1 x 12/14K 98M C -C

Specified M C R

2 x (45,200 bhp x 94.0 r/min)

Appropriate engines:

2 x 8K90M C


109,300 bhp x 104.0 r/min

Appropriate engine:

1 x 14/16K 98M C -C

Specified M C R

2 x (50,900 bhp x 94.0 r/min)


2 x 9K90M C / 2 x 7K 98M C


125,200 bhp x 104.0 r/min

Appropriate engine:

1 x 16K 98M C -C

Specified M C R

2 x (57,600 bhp x 94.0 r/min)


2 x 10K 90M C / 2 x 8K 98M C


7/11

The expected specified M C R and

engine types for the twin-skeg hull

with two propellers are based on the

assumption that the expected advan-

tage in propulsion performance can be

utilised to its full extent.

The service speed and margins should,

naturally, be adapted so as to utilise

the nominal rating of the engines.

The propeller speed for hulls with two

propellers may be further optimisedthrough detailed investigation of the

design of the hull and propellers.

The comprehensive programme of

90 and 98 cm bore engines from M AN

B& W Diesel offers ship designers the

possibility of choosing propeller speeds

freely within the range of 76.0 r/min for

the S90M C -C engine type over 83.0

r/min for the L90M C -C engine type and

94.0 r/min for the K 90/98M C engine

types to 104.0 r/min for the K 90/98MC-C

engine types.

Design Aspects of LargeMC Engines

As can be seen from the above, the

main engines relevant for the very large

containerships are the 90 and 98 cm

bore engines.

The L/K 90M C /M C -C were introduced

more than ten years ago, and since

then some 180 engines have been

ordered.

The K 98M C -C and K 98M C were intro-

duced much later, in 1994 and 1997,

and by now 20 engines have been or-

dered.

These include 10 x 7K98M C ,

5 x 10K98M C -C and 5 x 12K98M C -C

engines.

Since the introduction of the M C engines

in 1982, more than 4,600 engines have

entered service. During this long period

there has been a continuous updating

of the design in order to meet new

demands for reliability and power.

O ne of the important steps in the

development of the K98 engines has

been to secure optimal combustion

with low emission parameters without

sacrificing fuel oil consumption and, at

the same time, protecting and con-

trolling the heat-exposed parts in the

combustion chamber.

These goals have been achieved byvirtue of a new combustion chamber,

called O ros geometry, developed on

the basis of advanced C FD calculations

of various chamber configurations.

With the O ros geometry (shown in

Figures 8 and 9), we have concentrated

the combustion air around the fuel

nozzles, and obtained a greater distance

from the nozzles to the piston top. This

has resulted in lowerheat load on the

piston top and unchanged heat load

on the cylinder cover and exhaust valve.

8

Features:

H igh topland

O ros piston top geometry

C PR top ring

Alu-coat piston rings

Bore cooled, forged piston

of heat resistant steel

P iston cleaning ring

Verification:

Extensive calculations

C omprehensive tests on K 90M C and

K 90M C-C

Service test on K 90M C

Improvements:

Approx. 100 C lower temperature

on top compared to former type piston

Elimination of Inconel coating on piston top

Increased chrome layer thickness in bottom

of ring grooves

Anti-erosion bushing in oil outlet in piston

rod foot

o

P revious Oros g eometry

Fig. 8: Oros combustion chamber geometry


8/11

9

New Oros K98MC-CK90MC-C

Fig. 10: Heat loads on p iston

100% Load

G as side M ean 499 , max 509 M ean 409 , max 421C ooling oil side M ean 197 , max 209 M ean 185 , max 216

Valve seat M ean 439 , max 456 M ean 448 , max 457

Underside M ean 563 , max 564 M ean 577 , max 577

Piston

crown

temperature

Exhaust valve

temperature

SectionM-E

E

FHON

M

G

DK

E

FHON

M

G

SectionM-E

DK

C onventional design New O ros design

9 9

19

17

15

13 11

9 7 5

3 1 1

3

5 7 9

1 1 1 3

15

17

19

16

14 10 6

1014

16

57

5 7

11

13

15

1

2

3 3

4 4

810

12

1413

15

11 6 68 10

12

14

2 2

6

oC

oC

oC

oC

o

CoC

o

CoC

oC

oC

oC

oC

oC

oC

oC

oC

Fig. 9: Oros combustion chamber geometry

Relativeheat load


9/11

Actual temperature measurements on

the piston top are shown in Figure 9.

A comparison with measurements on a

conventional piston top shows that the

temperature level has been lowered

substantially, by 80-90C .

The reduction in heat load is illustrated

in Figure 10, which compares the heat

load on a K90M C -C piston of the tradi-

tional design with a K 98M C -C piston of

the new O ros design.

The mean heat input during combustion

is reduced by more than 20% , and the

local peak heat load is reduced by

25-35% .

Exhaust gas emissions tests have been

performed with conventional fuel valves,

mini-sac fuel valves and slide-type fuel

valves.

The results of the NO x measurements

are shown in Figure 11 when using the

slide-type fuelvalve and, as can be seen,the IM O NO x compliance is ensured

with a good margin for both the slide-type

and the mini-sac fuelvalves, which are

standard for all large bore M C engines.

This new combustion chamber design

has already been introduced on a num-

ber of M C engines and is the present

standard on all large bore M C /M C -C

engines.

Besides this very important feature, it is

obvious that other well-known designfeatures have been included, such as

high-topland pistons, which reduces

the thermal load inflicted on the piston

rings by the combustion gases. T his

has improved the performance of the

piston ring pack significantly, resulting

in higherTBO s (time between overhauls)

for the piston. Tests with high-topland

pistons were started about five years

ago on an S80M C engine and showed

a significant improvement in the general

combustion chamber condition.

The use of the high topland piston alsomeans that the mating surfaces between

cylinder liner and cylinder cover has

been lowered, thusreducing the thermal

load on the cylinder liner and improving

the conditions for lubricating it.

The piston ring pack features a top

piston ring of the so-called Controlled

Pressure Relief (C PR ring) design. This

reduces the thermal load on the ring

pack, as the leak gas flow is divided

over the six leakage grooves, Figure

12. T he ring height was increased toensure the strength of the finger seal.

The lower rings are all of the oblique

cut type.

10

Top piston ring with double-lap S-seal

and 6 C ontrolled Pressure Relief (C PR )

gaps

Even heat distribution on 2nd piston ring

2nd, 3rd and 4th piston rings with oblique

cut ring gaps

New piston ring material: R VK -C with

A lu-bronze coating

Fig. 12 : CPR piston ring

NO x (g/kWh)

20

10

8

6

4

2

50 75

0

18

100

16

12

14

0 25

Load (% -M CR )

IMO NO x (E3-cycle) = 14.3 g/kWh

Fig. 11 : NOxemission fo r slide type fuel valve


10/11

Initially, the height of both the top ring

and the second ring was increased

because cases with too short time

between overhauls were found to be

related to these two rings. The main

reason was that the rings lost their

tension relatively quickly due to the

thermal load, which resulted in more

frequent piston overhauls.

The use of higher 1. and 2. rings gave

a good improvement, and the tendencyto

collapsed rings wasgreatlyreduced.

With the introduction of the M k 5 version

of the K 80/90M C /M C -C engines, some

cases of scuffing occurred. These were

solved with the introduction of the CPR

top piston ring with a cermet coating

on the running surface.

A further improvement was obtained by

introducing the P iston C leaning (P C )

ring. T he purpose of this ring, shown in

Figure 13, is to control ash and carbon

deposits on the piston topland and

thus prevent contact between thecylinder liner and these deposits, which

would remove part of the cylinder oil

from the liner wall. Long-term tests on

an S80M C engine since 1994 have

shown positive results, verifying that

bore polishmay be a decisive factor

in the deterioration of the cylinder

condition. PC rings are therefore now

standard on large bore M C engines.

In connection with the introduction of

the Piston Cleaning ring, the ring pack

was modified to include Alu-coat on all

rings.

The Alu-coat is applied as a running-incoating. T he advantage is reduced

requirement for running-in time, and

fewer load limitations during running-in

after a piston overhaul. T his results in

safer running-in and in cylinder oil con-

sumption savings.

Service experience has shown that the

C PR top ring solves the scuffing also for

the second ring.

11

C ylinder

Lubri-

cator

Lubri-

catorAccumulator

Solenoid valve Solenoid valve

Sensor Sensor

C ylinder oil

service tank

Pump station

with

stand-by pumps

To other

cylinders

To other

cylinders

To other

cylinders

Tachosignal

Indexsignal

LCDsignal

Indication

operationpanel

Alarmsystem

Slow-downsystem

Control unitwith

back-up system

Fig. 14: Cylinder lubrication with Alpha lubricators

Piston - high topland

Piston cleaning ring C ylinder liner

C ylinder cover

Fig. 13: Piston cleaning (PC) ring


11/11

C onsequently, the design has been modi-

fied to a high top ring of the C PR-type,

whereas the three lower rings are of the

usual low type.

Alphalubricatorsandlubeoilconsumption

Reduction of the cylinder lube oilconsump-

tion represents a significant potential saving

for engine operators. It is therefore an im-portant development target for M AN B& W

to reduce the lube oildosage without in-

creasing the wear ratesor reducing TBO s.

C ylinder oil must be injected into the

cylinder at the exact position and time

that ensuresthe optimaluse of the lube oil.

Having realised that this is hardly possible

with the conventional, mechanical cylinder

lubricators, we have engaged ourselves in

the development of a computer controlled

electronic cylinder lubrication system, the

Alpha lubricator, for application on currentcamshaft controlled engines as well as on

computer controlled Intelligent Engines,

see Figure 14.

The Alpha lubrication system features

a high-pressure pump and an injector

which injects a specific volume of oil

into each cylinder for every fourth

revolution, Figure 14. The system is

controlled in such a way that the oil

can be introduced to the individual

cylinder at any piston position but,

preferably, when the piston rings are

adjacent to the lubricating quills.

The computer sending an on/off

signal to a solenoid valve controls

the injection function. After a prede-

termined time interval, the computer

transmits an off signal to the sole-

noid valve, which shuts off the sys-

tem pressure and opens the return

oil system. The oil dosage can be

changed by adjusting the injection to

e.g. every fifth, sixth, etc. revolution

(or anyfigure in between, such as

every 4.5 revolutionby alternating

between injection every fourth andevery fifth revolution).

The amount of oil injected can be

controlled according to engine load

and raised as required: for example at

load changes or start/stop.

In the event of a malfunctioning solenoid

valve or transducer, the oil dosage will

automatically be increased for the

cylinder in question to the maximum

volume on the other lubricator. If the oil

pressure fails, the computer will start a

standbypump and close down the faulty

pump. If the computer or position sen-sors fail, a back-up computer will take

over and ensure sufficient (untimed)

lubrication until the fault has been

corrected.

The system, fine tuned on M AN B& Ws

4T50M X research engine, has returned

good results on a 7S35M C engine and

has now been in service for more than

one year on a K90M C engine. This sys-

tem has proved high reliability and very

good cylinder condition with unchanged

wear rates with a cylinder oil feed ratethat is lower than our recommendations

with the conventional mechanically

timed lubricator.

Conclusion

With the new and by now fully tested

K 98 engine, M AN B& W iswell prepared

to meet the demand for increasingly

larger main engines for containerships.

This engine and other large bore M C

engines are equipped with the latest

design features known to give high

reliability and good operational econ-omy.

12

Pressure sensor

for

control of lubrication

C ylinder

lube oil

inlet

45 bar

C ylinder lube oil

outlet

O utlets

for cylinder liner

lube oil points

Signal for lubrication

from control unit

Spacer

for basic setting of

pump stroke

Solenoid

valveP

A

T

Adjusting

screw

Actuator

piston

Injection plungers

A TP

Fig. 15: Cylinder lubricator unit

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Propulsion Large Containership