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MAN B&W 18.06
Water In Oil Monitoring System
In case the lubricating oil becomes contaminated
with an amount of water exceeding our limit of
0.2%, acute corrosive wear of the crosshead bearing
overlayer may occur. The higher the water content,
the faster the wear rate.
To prevent water from accumulating in the lube
oil and, thereby, causing damage to the bearings,
the oil should be monitored manually or automatically
by means of a Water In Oil (WIO) monitoring
system connected to the engine alarm and monitoring
system. In case of water contamination
the source should be found and the equipment
inspected and repaired accordingly.
The WIO system should trigger an alarm when
the water content exceeds 0.2%, and preferably
again when exceeding 0.35% measured as absolute
water content.
Some WIO systems measure water activity, ie
the relative availability of water in a substance
expressed in ‘aw’ on a scale from 0 to 1. Here, ‘0’
indicates oil totally free of water and ‘1’ oil fully
saturated by water. The correlation to absolute
water content in normal running as well as alarm
condition <strong>is</strong> as follows:
Engine condition Abs. water Water
content, % activity, aw
High alarm level 0.2 0.5
High High alarm level 0.35 0.9
ME, ME-C and ME-GI engines are as standard
specified with Water In Oil monitoring system.
Please note: Corrosion of the overlayer <strong>is</strong> a potential
problem only for crosshead bearings, because
only crosshead bearings are designed with an
overlayer. Main and crankpin bearings may also
suffer irreparable damage from water contamination,
but the damage mechan<strong>is</strong>m would be different
and not as acute.
Liner Wall Monitoring System
Page 4 of 5
The Liner Wall Monitoring (LWM) system monitors
the temperature of each cylinder liner. It <strong>is</strong> to
be regarded as a tool providing the engine room
crew the possibility to react with appropriate
countermeasures in case the cylinder oil film <strong>is</strong>
indicating early signs of breakdown.
In doing so, the LWM system can ass<strong>is</strong>t the crew
in the recognition phase and help avoid consequential
scuffing of the cylinder liner and p<strong>is</strong>ton
rings.
Signs of oil film breakdown in a cylinder liner
will appear by way of increased and fluctuating
temperatures. Therefore, recording a preset max
allowable absolute temperature for the individual
cylinder or a max allowed deviation from a calculated
average of all sensors will trigger a cylinder
liner temperature alarm.
The LWM system includes two sensors placed in
the manoeuvring and exhaust side of the liners,
near the p<strong>is</strong>ton skirt TDC position. The sensors
are interfaced to the ship alarm system which
monitors the liner temperatures.
For each individual engine, the max and deviation
alarm levels are optim<strong>is</strong>ed by monitoring the temperature
level of each sensor during normal service
operation and setting the levels accordingly.
The temperature data <strong>is</strong> logged on a PC for one
week at least and preferably for the duration of a
round trip for reference of temperature development.
All types 98 and 90 ME and ME-C engines as well
as K80ME-C9 are as standard specified with Liner
Wall Monitoring system. For all other engines, the
LWM system <strong>is</strong> <strong>available</strong> as an option: 4 75 136.
MAN B&W ME/ME�C/ME�GI engines 198 67 26�5.3
MAN Diesel