W20PG
W20PG
W20PG
This Project Guide provides engine data and system proposals for the early design phase of marine engine
installations. For contracted projects specific instructions for planning the installation are always delivered.
Any data and information herein is subject to revision without notice.
This 1/2002 issue replaces all previous issues of the Wärtsilä 20 Project Guides. Numerous revisions have been
made. Also the structure of this Project Guide has been amended.
Wärtsilä Finland Oy
Marine & Licensing
Application Technology
THIS PUBLICATION IS DESIGNED TO PROVIDE AS ACCURATE AND AUTHORITIVE INFORMATION REGARDING THE SUBJECTS COVERED AS WAS
AVAILABLE AT THE TIME OF WRITING. HOWEVER, THE PUBLICATION DEALS WITH COMPLICATED TECHNICAL MATTERS AND THE DESIGN OF
THE SUBJECT AND PRODUCTS IS SUBJECT TO REGULAR IMPROVEMENTS, MODIFICATIONS AND CHANGES. CONSEQUENTLY, THE PUBLISHER
AND COPYRIGHT OWNER OF THIS PUBLICATION CANNOT TAKE ANY RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR OMISSIONS IN THIS
PUBLICATION OR FOR DISCREPANCIES ARISING FROM THE FEATURES OF ANY ACTUAL ITEM IN THE RESPECTIVE PRODUCT BEING DIFFERENT
FROM THOSE SHOWN IN THIS PUBLICATION. THE PUBLISHER AND COPYRIGHT OWNER SHALL NOT BE LIABLE UNDER ANY CIRCUMSTANCES,
FOR ANY CONSEQUENTIAL, SPECIAL, CONTINGENT, OR INCIDENTAL DAMAGES OR INJURY, FINANCIAL OR OTHERWISE, SUFFERED BY ANY
PART ARISING OUT OF, CONNECTED WITH, OR RESULTING FROM THE USE OF THIS PUBLICATION OR THE INFORMATION CONTAINED
THEREIN.
Table of Contents
1. General data and outputs . . . . . . . . . . . . . . . . . . . 1 12. Turbocharger and air cooler cleaning . . . . . . . . 79
1.1. Technical main data . . . . . . . . . . . . . . . . . . . . . . . . . 1 12.1. Turbine cleaning system (5Z03) . . . . . . . . . . . . . . . 79
1.2. Maximum continuous output . . . . . . . . . . . . . . . . . . 1
1.3. Reference conditions . . . . . . . . . . . . . . . . . . . . . . . . 1 13. Exhaust emissions . . . . . . . . . . . . . . . . . . . . . . . . 80
1.4. Principal dimensions and weights . . . . . . . . . . . . . . 4 13.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
13.2. Diesel engine exhaust components . . . . . . . . . . . . 80
2. Operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . 6 13.3. Marine exhaust emissions legislation. . . . . . . . . . . 81
2.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 13.4. Methods to reduce exhaust emissions . . . . . . . . . 82
2.2. Matching the engines with driven equipment . . . . . 7
2.3. Loading capacity . . . . . . . . . . . . . . . . . . . . . . . . . . 12 14. Automation system . . . . . . . . . . . . . . . . . . . . . . . 84
2.4. Ambient conditions . . . . . . . . . . . . . . . . . . . . . . . . 13 14.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
14.2. Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3. Technical data tables . . . . . . . . . . . . . . . . . . . . . . 14 14.3. Safety System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
14.4. Speed Measuring (8N03) . . . . . . . . . . . . . . . . . . . . 85
4. Description of the engine . . . . . . . . . . . . . . . . . . 24 14.5. Sensors & signals. . . . . . . . . . . . . . . . . . . . . . . . . . 86
4.1. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 14.6. Local instrumentation. . . . . . . . . . . . . . . . . . . . . . . 88
4.2. Main components . . . . . . . . . . . . . . . . . . . . . . . . . 24 14.7. Control of auxiliary equipment . . . . . . . . . . . . . . . . 88
4.3. Cross sections of the engine . . . . . . . . . . . . . . . . . 26 14.8. Speed control (8I03). . . . . . . . . . . . . . . . . . . . . . . . 89
4.4. Overhaul intervals and expected life times . . . . . . 27 14.9. Microprocessor based engine control system (WECS)
(8N01). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5. Piping design, treatment and installation . . . . . 28
5.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 15. Electrical power generation and management 105
5.2. Pipe dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 15.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
5.3. Trace heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 15.2. Electric power generation . . . . . . . . . . . . . . . . . . 106
5.4. Pressure class . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 15.3. Electric power management system (PMS) . . . . . 108
5.5. Pipe class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 15.4. Typical one line main diagrams . . . . . . . . . . . . . . 111
5.6. Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.7. Local gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 16. Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.8. Cleaning procedures . . . . . . . . . . . . . . . . . . . . . . . 31 16.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.9. Flexible pipe connections . . . . . . . . . . . . . . . . . . . 31 16.2. Steel structure design . . . . . . . . . . . . . . . . . . . . . 113
16.3. Mounting of main engines . . . . . . . . . . . . . . . . . . 113
6. Fuel oil system . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 16.4. Mounting of generating sets . . . . . . . . . . . . . . . . 119
6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 16.5. Reduction gear foundations. . . . . . . . . . . . . . . . . 123
6.2. MDF installations . . . . . . . . . . . . . . . . . . . . . . . . . . 33 16.6. Free end PTO driven equipment foundations . . . 123
6.3. HFO installations . . . . . . . . . . . . . . . . . . . . . . . . . . 39 16.7. Flexible pipe connections . . . . . . . . . . . . . . . . . . 123
7. Lubricating oil system . . . . . . . . . . . . . . . . . . . . . 49 17. Vibration and noise . . . . . . . . . . . . . . . . . . . . . . 124
7.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 17.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
7.2. Lubricating oil quality . . . . . . . . . . . . . . . . . . . . . . . 49 17.2. External forces and couples. . . . . . . . . . . . . . . . . 124
7.3. Internal lubricating oil system. . . . . . . . . . . . . . . . . 51 17.3. Mass moments of inertia . . . . . . . . . . . . . . . . . . . 125
7.4. External circulating oil system . . . . . . . . . . . . . . . . 52 17.4. Air borne noise . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
7.5. Separation system . . . . . . . . . . . . . . . . . . . . . . . . . 53
7.6. Filling, transfer and storage . . . . . . . . . . . . . . . . . . 53 18. Power transmission . . . . . . . . . . . . . . . . . . . . . . 126
7.7. Crankcase ventilation system . . . . . . . . . . . . . . . . 53 18.1. General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7.8. Flushing instructions . . . . . . . . . . . . . . . . . . . . . . . 54 18.2. Connection to alternator . . . . . . . . . . . . . . . . . . . 126
7.9. System diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . 55 18.3. Flexible coupling . . . . . . . . . . . . . . . . . . . . . . . . . 127
18.4. Clutch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8. Compressed air system . . . . . . . . . . . . . . . . . . . . 57 18.5. Shaftline locking device and brake . . . . . . . . . . . 127
8.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 18.6. Power-take-off from the free end. . . . . . . . . . . . . 128
8.2. Compressed air quality . . . . . . . . . . . . . . . . . . . . . 57 18.7. Torsional vibration calculations . . . . . . . . . . . . . . 129
8.3. Internal starting air system . . . . . . . . . . . . . . . . . . . 57 18.8. Turning gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8.4. External starting air system . . . . . . . . . . . . . . . . . . 58
19. Engine room layout . . . . . . . . . . . . . . . . . . . . . . 130
9. Cooling water system . . . . . . . . . . . . . . . . . . . . . 61 19.1. Crankshaft distances . . . . . . . . . . . . . . . . . . . . . . 130
9.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 19.2. Space requirements for maintenance . . . . . . . . . 133
9.2. Internal cooling water system . . . . . . . . . . . . . . . . 62 19.3. Handling of spare parts and tools . . . . . . . . . . . . 133
9.3. External cooling water system . . . . . . . . . . . . . . . . 65 19.4. Required deck area for service work . . . . . . . . . . 133
9.4. Example system diagrams . . . . . . . . . . . . . . . . . . . 70
20. Transport dimensions and weights . . . . . . . . . 134
10. Combustion air system . . . . . . . . . . . . . . . . . . . . 75 20.1. Lifting of engines . . . . . . . . . . . . . . . . . . . . . . . . . 134
10.1. Engine room ventilation . . . . . . . . . . . . . . . . . . . . . 75 20.2. Engine components . . . . . . . . . . . . . . . . . . . . . . . 135
10.2. Combustion air quality . . . . . . . . . . . . . . . . . . . . . . 75
10.3. Combustion air system design. . . . . . . . . . . . . . . . 75 21. Dimensional drawings . . . . . . . . . . . . . . . . . . . . 137
Engine Output at
720 RPM/60 Hz 750 RPM/50 Hz 900 RPM/60 Hz 1000 RPM/50 Hz
Engine Generator Engine Generator Engine Generator Engine Generator
(kW) (kVA) (kW) (kVA) (kW) (kVA) (kW) (kVA)
4L20 520 620 540 640 680 810 720 855
5L20 775 920 825 980
6L20 780 930 810 960 1020 1210 1080 1280
8L20 1040 1240 1080 1280 1360 1615 1440 1710
9L20 1170 1390 1215 1440 1530 1815 1620 1925
The specific fuel consumption is stated in the chapter for • air temperature 25°C
Technical data with the reference for the engine driven • relative humidity 30%
equipment and the effect they have on the specific fuel
consumption. The statement applies to engines operating • charge air coolant temperature 25°C
in ambient conditions according to ISO 3046-1 : 1995(E). For other than ISO 3046-1 conditions the same standard
gives correction factors on the fuel oil consumption.
• total barometric pressure 100 kPa
1) Use of ISO-F-DMC category fuel is allowed provided that the fuel treatment system is equipped with a fuel centrifuge.
2) Additional properties specified by the engine manufacturer, which are not included in the ISO specification or differ from
the ISO specification.
3) In some geographical areas there may be a maximum limit.
4) Different limits specified for winter and summer qualities.
Lubricating oil, foreign substances or chemical waste, hazardous to the safety of the installation or detrimental to the perfor-
mance of the engines, should not be contained in the fuel.
The fuel specification “HFO 2" is base on the ISO This tighter specification is an alternative and by using
8217:1996(E) standard and covers the fuel categories this specification, longer overhaul intervals of specific
IS-F-RMA10 - RMK55. Additionally, the engine manu- engine components are possible. See table in the chapter
facturer has specified the fuel specification ”HFO 1". for Description of the engine.
Table 1.4. HFO Specifications
1) Max. 1010 kg/m³ at 15°C provided the fuel treatment system can remove water and solids.
2) Straight run residues show CCAI values in the 770 to 840 range and are very good ignitors. Cracked residues delivered as
bunkers may range from 840 to - in exceptional cases - above 900. Most bunkers remain in the max. 850 to 870 range at the
moment.
3) Sodium contributes to hot corrosion on exhaust valves when combined with high sulphur and vanadium contents. So-
dium also contributes strongly to fouling of the exhaust gas turbine blading at high loads. The aggressiveness of the fuel de-
pends not only on its proportions of sodium and vanadium but also on the total amount of ash constituents. Hot corrosion
and deposit formation are, however, also influenced by other ash constituents. It is therefore difficult to set strict limits
based only on the sodium and vanadium content of the fuel. Also a fuel with lower sodium and vanadium contents that
specified above, can cause hot corrosion on engine components.
4) Additional properties specified by the engine manufacturer, which are not included in the ISO specification.
Lubricating oil, foreign substances or chemical waste, hazardous to the safety of the installation or detrimental to the perfor-
mance of the engines, should not be contained in the fuel.
The limits above also correspond to the demands of the following standards. The properties marked with 4) are not specifi-
cally mentioned in the standards but should also be fulfilled.
• BS MA 100: 1996, RMH 55 and RMK 55 • CIMAC 1990, Class H55 and K55
• ISO 8217: 1996(E), ISO-F-RMH 55 and RMK 55
Engine A* A B* B C* C D E F G H I K
4L20 2510 1348 1483 1800 325 725 1480 155 718 980
5L20 2833 1423 1567 1800 325 725 1780 155 718 980
6L20 3254 3108 1528 1348 1580 1579 1800 325 624 2080 155 718 980
8L20 3973 3783 1614 1465 1756 1713 1800 325 624 2680 155 718 980
9L20 4261 4076 1614 1449 1756 1713 1800 325 624 2980 155 718 980
Weight
Engine M* M N* N P* P R* R S* S T* T
**
4L20 854 665 920 248 694 349 7.2
5L20 938 688 1001 328 750 370 7.8
6L20 951 950 589 663 1200 971 328 328 762 763 273 343 9.3
8L20 1127 1084 708 738 1224 1000 390 390 907 863 325 339 11
9L20 1127 1084 696 731 1224 1000 390 390 907 863 325 339 11.6
* Turbocharger at flywheel end
** Weights (in Metric tons) with liquids (wet sump) but without flywheel
Weight
ENGINE A* B* C D* E* F* G* H* I K* L* M
[ton]
4L20 4910 4050 665 2460 728 990 1270 1770 1800 1580 2338 1168 14.0
5L20 5190 3945 688 2430 728 1075 1270 1770 1800 1580 2458 1329 15.1
895/ 1270/ 1770/ 1800 1580/ 2243/
6L20 5290 4540 663 2300 728 1299 16.8
975 1420 1920 1730 2323
1420 / 1920/ 1730/
8L20 6010 5080 731 2310 728 1025 1800 2474 1390 20.7
1570 2070 1880
1075/ 1570/ 2070/ 1800 1880/ 2524/
9L20 6550 5415 731 2580 728 1390 23.8
1125 1800 2300 2110 2574
* Values are based on standard alternator, whose type (water or air cooled) and size affects to width, length, height and weight.
Weight is based on wet sump engine with engine liquids.
2. Operating ranges
2.1. General sions, lower fuel consumption and SCR compatibility also
contribute to the restriction of the operating field.
The available operating field of the engine depends on the
required output, and these should therefore be determined A matter of high importance is the matching of the propel-
ler and the engine. Weather conditions, acceleration, the
together. This applies to both FPP and CPP applications.
loading condition of the ship, draught and trim, the age and
Concerning FPP applications also the propeller matching
must be clarified. fouling of the hull, and ice conditions all play an important
role.
A diesel engine can deliver its full output only at full engine
speed. At lower speeds the available output and also the With a FP propeller these factors all contribute to moving
the power absorption curve towards higher thermal load-
available torque are limited to avoid thermal overload and
ing of the engine. There is also a risk for surging of the
turbocharger surging. This is because the turbocharger is
less efficient and the amount of scavenge air supplied to the turbocharger at a certain part load (when moving to the left
engine is low, and consequently also the cooling effect on in the power-rpm diagram). On the other hand, with a new
the combustion chamber. Often e.g. the exhaust valve tem- and clean hull in ballast draft the power absorption is
lighter and full power will not be absorbed as the maximum
perature can be higher at low load (when running accord-
engine speed limits the speed range upwards. These draw-
ing to the propeller law) than at full load. Furthermore, the
smallest distance to the so-called surge limit of the com- backs are avoided by specifying CP-propellers.
pressor typically occurs at part load. Some margin is re- A similar problem is encountered on twin-screw (or
quired to permit some reasonable wear and fouling of the multi-screw) ships with fixed-pitch propellers running
turbocharging system and different ambient conditions with only one propeller. If one propeller is wind-milling
(e.g. suction air temperature). (rotating freely), the other propeller will feel an increased
As a rule, the higher the specified mean effective pressure power absorption, and even more so, if the other propeller
the narrower is the permitted engine operating range. is blocked. The phenomenon is more pronounced on ships
There is a trend in the industry to specify higher and higher with a small block coefficient. The issue is illustrated in the
diagram below.
outputs, unfortunately on the expense of the width of the
operating field. This is the reason why separate operating
fields may be specified for different output stages, and the
available output for FP-propellers may be lower than for
CP-propellers. Today’s development towards lower emis-
Figure 2.1. Propeller power absorption in different
conditions - example
3
Single screw ships
Prope ller power absorption, relative
Bollard pull
Free running
0
0 20 40 60 80 100
Propeller speed, relative
The figure also indicates the magnitude of the so-called 2.2. Matching the engines with
bollard pull curve, which means the propeller power ab-
sorption curve at zero ship speed. It is a relevant condition driven equipment
for some ship types, such as tugs, trawlers and icebreakers.
This diagram is valid for open propellers. Propellers run- 2.2.1. CP-propeller
ning in nozzles are less sensitive to the speed of advance of Controllable pitch propellers are normally dimensioned
the ship. and classified to match the Maximum Continuous Rating
The bollard pull curve is also relevant for all FPP applica- of the prime mover(s). In case two (or several) engines are
tions since the power absorption during acceleration is al- connected to the same propeller it is normally dimensioned
ways somewhere between the free running curve and the corresponding to the total power of all connected prime
bollard pull curve! If the free sailing curve is very close to movers. This is also the case if the propeller is driven by
the 100% engine power curve and the bollard pull curve at prime movers of different types, as e.g. one diesel engine
the same time is considerably higher than the 100% engine and one electric motor (which may work as a shaft genera-
power curve, then the acceleration from zero ship speed tor in some operating modes). In case the total power of all
will be very difficult. This is because the propeller will re- connected prime movers will never be utilised, classifica-
quire such a high torque at low speed that the engine is not tion societies can approve a dimensioning for a lower
capable of increasing the speed. As a consequence the pro- power in case the plant is equipped with an automatic over-
peller will not develop enough thrust to accelerate the ship. load protection system. The rated power of the propeller
Heavy overload will also occur on a twin-screw vessel with will affect the blade thickness, hub size and shafting dimen-
FP propellers during manoeuvring, when one propeller is sions.
reversed and the other one is operating forward. When Designing a CP-propeller is a complex issue, requiring
dimensioning FP propellers for a twin screw vessel, the compromises between efficiency, cavitation, pressure
power absorption with only one propeller in operation pulses, and limitations imposed by the engine and a possi-
should be max. 90% of the engine power curve, or alterna- ble shaft generator, all factors affecting the blade geometry.
tively the bollard pull curve should be max 120% of the en- Generally speaking the point of optimisation (an optimum
gine power curve. Otherwise the engine must be de-rated pitch distribution) should correspond to the service speed
20-30% from the normal output for FPP applications. This and service power of the ship, but the issue may be compli-
will involve extra costs for non-standard design and sepa- cated in case the ship is intended to sail with various ship
rate EIAPP certification. For this reason it is recom- speeds, and even with different operating modes. Shaft
mended to select CP-propellers for twin-screw ships with generators or generators (or any other equipment) con-
mechanical propulsion. nected to the free end of the engine should be considered
An FP-propeller should never be specified for a in case these will be used at sea.
twin-in/single-out gear as one engine is not capable of The propeller efficiency is typically highest when running
driving a propeller designed for the power of two engines. along the propeller curve defined by the design pitch, in
For ships intended for operation in heavy ice, the addi- other word requiring the engine at part load to run slowly
tional torque of the ice should furthermore be considered. and heavily. Typically also the efficiency of a diesel engine
running at part load is somewhat higher when running at a
For selecting the machinery, typically a sea margin of
lower speed than the nominal.
10…15 % is applied, sometimes even 25…30 %. This
means the relative increase in shaft power from trial condi- Pressure side cavitation may easily occur when running at
tions to typical service conditions (a margin covering in- high propeller speed and low pitch. This is a noisy type of
crease in ships resistance due to fouling of hull and cavitation and it may also be erosive. However the pressure
propeller, rough seas, wind, shallow water depth etc). Fur- side cavitation behaviour can be improved a lot by a suit-
thermore, an engine margin of 10…15 % is often applied, able propeller blade design. Also cavitation at high power
meaning that the ship’s specified service speed should be may cause increased pressure pulses, which can be reduced
achieved with 85…90 % of the MCR. These two inde- by increased skew angle and optimized blade geometry.
pendent parameters should be selected on a project spe- It is of outmost importance that the propeller designer has
cific basis. information about all the actual operation conditions for
The minimum speed of the engine is a project specific is- the vessel. Often the main objective is to minimise the ex-
sue, involving issues like torsional vibrations, elastic tent and fluctuation of the suction side cavitation to reduce
mounting, built-on pumps etc. propeller-induced hull vibrations and noise at high power,
while simultaneously avoiding noisy pressure side cavita-
In projects where the standard operating field, standard
tion and a large drop in efficiency at reduced propeller
output, or standard nominal speed do not satisfy all project
pitch and power.
specific demands, the engine maker should be contacted.
The propeller may enter the pressure side cavitation area To optimise the operating performance considering these
already when reducing the power to less than half, main- limitations CP-propellers are typically operating along a
taining nominal speed. In twin-in/single-out installations preset combinator curve, combining optimum speed and
the plant cannot be operated continuously with one engine pitch throughout the whole power range, controlled by
and a shaft generator connected, if the shaft generator re- one single control lever on the bridge. Applications with
quires operation at nominal propeller speed. two engines connected to the same propeller must have
Many solutions are possible to solve this problem: separate combinator curves for one engine operation and
twin engine operation. This applies similarly to twin-screw
• The shaft generator (connected to the secondary side of
vessels. Two or several combinator curves may be foreseen
the clutch) is used only when sailing with high power.
in complicated installations for different operating modes
• The shaft generator (connected to the secondary side of (one-engine, two-engines, manoeuvring, free running etc).
the clutch) is used only when manoeuvring with low or At a given propeller speed and pitch, the ship’s speed af-
moderate power, the transmission ratio being selected to fects the power absorption of the propeller. This effect is
give nominal frequency at reduced propeller speed. to some extent ship-type specific, being more pronounced
• The shaft generator is connected to the primary side of on ships with a small block coefficient. The power absorp-
the clutch of one of the engines, and can be used inde- tion of the propeller can sometimes be almost twice as high
pendently from the propeller, e.g. to produce power for during acceleration than during free steady-state running.
thrusters during manoeuvring. Navigation in ice can also add to the torque absorption of
• No shaft generator is installed. the propeller.
This type of issues are not only operational of nature, they An engine can deliver power also to other equipment like a
have to be considered at an early stage when selecting the pump, which can overload the engine if used without prior
machinery configuration. For all these reasons it is essential load reduction of the propeller.
to know the ship’s operating profile when designing the For the above mentioned reasons an automatic load con-
propeller and defining the operating modes. trol system is required in all installations running at variable
In normal applications no more than two engines should speed. The purpose of this system is to protect the engine
be connected to the same propeller. from thermal load and surging of the turbocharger. With
this system the propeller pitch is automatically reduced
CP-propellers typically have the option of being operated
when a pre-programmed load versus speed curve (the
at variable speed. To avoid the above mentioned pressure
“load curve”) is exceeded, overriding the combinator
side cavitation the propeller speed should be kept suffi-
curve if necessary. The load information must be derived
ciently below the cavitation limit, but not lower than neces-
from the actual fuel rack position and the speed should be
sary. On the other hand, there are also limitations on the
the actual speed (and not the demand). A so-called over-
engine’s side, such as avoiding thermal overload at lower
load protection, which is active only at full fuel pump set-
speeds.
tings, is not sufficient in variable speed applications.
The diagrams below show the operating ranges for
CP-propeller installations. The design range for the
combinator curve should be on the right hand side of the
nominal propeller curve. Operation in the shaded area is
permitted only temporarily during transients.
Operating field for CP Propeller The FP-propeller should normally be designed to absorb
Mechanical Fuel Stop MCR
100 maximum 85 % of the maximum continuous output of the
main engine (power transmission losses included) at nomi-
CSR
90 nal speed when the ship is on trial. Typically this corre-
(85%)
Max. Output Limit
80
sponds to 81 – 82 % for the propeller itself (excluding
Operation Temporarily
Allowed power transmission losses). This is typically referred to as
70 the “light running margin”, a compensation for expected
Nominal Propeller Curve
60
future drop in revolutions for a constant given power, typi-
Load (%)
cally 5-6 %.
50 Example of
Combinator Curve For ships intended for towing, the bollard pull condition
40
needs to be considered as explained earlier. The propeller
should be designed to absorb not more than 95 % of the
30 maximum continuous output of the main engine at nomi-
Min. Speed
20
nal speed when operating in towing or bollard pull condi-
Idling/Clutch-In
Speed Range tions, whichever service condition is relevant. In order to
10 reach 100 % MCR it is allowed to increase the engine speed
0
to 101.7 %. The speed does not need to be restricted to 100
30 40 50 60 70 80 90 100 110 % after bollard pull tests have been carried out. The ab-
Speed (%) sorbed power in free running and nominal speed is then
relatively low, e.g. 50 – 65 % of the output at service condi-
The clutch-in speed is a project specific issue. From the en- tions.
gine point of view, the clutch-in speed should be high Operating field for FP Propeller
enough to have a sufficient torque available, but not too MCR
Mechanical Fuel Stop
high. The slip time on the other hand should be as long as 100
possible. In practise longer slip times than 5 seconds are CSR
90
exceptions, but the clutch should typically be dimensioned Max. Output Limit
(85%)
so that it allows a slip time of at least 3 seconds. From the 80 Operation Temporarily
clutch point of view, a high clutch-in speed causes a high Allowed
thermal load on the clutch itself, which has to be taken into 70
Propeller Curves
account when specifying the clutch. A reasonable compro- 60
Load (%)
the engine with a typically single-stage reduction gear. The Speed (%)
sense of rotation of propellers in twin-screw ships is a pro- The engine is non-reversible, so the gear box has to be of
ject specific issue. the reversible type. A shaft brake should also be installed.
A Robinson diagram (= four-quadrant diagram) showing
2.2.2. FP-propeller
the propeller torque ahead and astern for both senses of ro-
The fixed pitch propeller needs a very careful matching, as tation is needed to determine the parameters of the crash
explained above. The operational profile of the ship is very stop.
important (acceleration requirements, loading conditions, FP-propellers in single-screw ships typically rotate clock-
sea conditions, manoeuvring, fouling of hull and propeller wise, requiring a counter clockwise sense of rotation of the
etc). engine with a typically single-stage (in the ahead mode) re-
verse reduction gear.
2.2.3. Water jets ter jet power absorption should be dimensioned close to
100% MCR to get out as much power as possible. How-
Water jets also requires a careful matching with the engine,
ever, some margin should be left, due to tolerances in the
similar to that of the fixed pitched propeller. However, power estimates of the jet and the small, but still present,
there are some distinctive differences between the increase in torque demand due to a possible increase in
dimensioning of a water jet compared to that of a fixed ship resistance.
pitch propeller.
The torque demand at lower speeds should also be care-
Water jets operate at variable speed depending on the
fully compared to the operating field of the engine.
thrust demand. The power absorption vs. rpm of a water Engines with highly optimised turbo chargers can have an
jet follows a cubic curve under normal operation. The operating field that does not cover the water jet power de-
power absorption vs. rpm is higher when the ship speed is mand over the entire speed range. Also the lower efficiency
reduced, with the maximum torque demand occurring
of the transmission and the reduction gear at part load
when manoeuvring astern. The power absorption vs. revo-
should be accounted for in the estimation of the power ab-
lution speed for a typical water jet is illustrated in the dia-
sorption. The time spent at manoeuvring should be con-
gram below. sidered as well, if the power absorption in manoeuvring
Water jet power absorption mode exceeds the operating field for continuous operation
for the engine. In projects where the standard operating
Normal operation
field does not satisfy all project specific demands, the en-
Manoeuvring, ahead
Relative waterjet power absorption
% % % rpm % Hz
This is also the case when the generator nominal speed is a The electrical system onboard the ship must be designed
multiple of the nominal speed of the engine. The number so that the diesel generators are protected from load steps
of teeth is selected to permit all teeth being in contact with that exceed the limit. Normally system specifications must
all teeth of the other gear wheel, to avoid uneven wear. To be sent to the classification society for approval and the
achieve this target, gear wheels with a multiple number of functionality of the system is to be demonstrated during
teeth compared with its smaller pair should be avoided. the ship’s trial.
This is valid for the main power transmission from the en- The loading performance is affected by the rotational iner-
gine to the propeller, as well as for PTOs for shaft genera- tia of the whole generating set, the speed governor adjust-
tors. In other words cases where a combination of tooth ment and behaviour, generator design, alternator
numbers giving exactly the desired transmission ratio can excitation system, voltage regulator behaviour and nomi-
be found, it is not feasible to use them. nal output.
The maximum output of diesel engines driving auxiliary Loading capacity and overload specifications are to be de-
generators and diesel engines driving generators for pro- veloped in co-operation between the plant designer, en-
pulsion is 110 % of the MCR. gine manufacturer and classification society at an early
stage of the project. Features to be incorporated in the
power management systems are presented in the Chapter
2.3. Loading capacity for electrical power generation.
The loading rate of a highly supercharged diesel engine
must be controlled, because the turbocharger needs time to 2.3.3. Auxiliary engines driving generators
accelerate before it can deliver the required amount of air. The load should always be applied gradually in normal op-
The load should always be applied gradually in normal op- eration. This will prolong the lifetime of engine compo-
eration. nents. The class rules only determine what the engine must
be capable of, if an emergency situation occurs. In an emer-
2.3.1. Diesel-mechanical propulsion gency situation the engine can be loaded in three equal
The loading is to be controlled by a load increase steps with minimum 5 seconds between each step. Pro-
programme, which is included in the propeller control sys- vided that the engine is preheated to a HT-water tempera-
tem. ture of 60…70ºC the engine can be loaded immediately
after start.
2.3.2. Diesel-electric propulsion The fastest loading is achieved with a successive gradual
increase in load from 0 to 100 %. It is recommended that
Class rules regarding load acceptance capability should not the switchboards and the power management system are
be interpreted as guidelines on how to apply load on the en- designed to increase the load as smoothly as possible.
gine in normal operation. The class rules only determine
The electrical system onboard the ship must be designed
what the engine must be capable of, if an emergency situa-
tion occurs. In an emergency situation the engine can be so that the diesel generators are protected from load steps
loaded in three equal steps in accordance with class require- that exceed the limit. Normally system specifications must
be sent to the classification society for approval and the
ment.
functionality of the system is to be demonstrated during
the ship’s trial.
4.2.6. Piston
The piston is of composite design with nodular cast iron
skirt and steel crown. The piston skirt is pressure lubri-
cated, which ensures a well-controlled oil flow to the cylin-
der liner during all operating conditions. Oil is fed through
the connecting rod to the cooling spaces of the piston. The
piston cooling operates according to the cocktail shaker
principle. The piston ring grooves in the piston top are
hardened for better wear resistance.
4.2.3. Connecting rod The camshaft is built of one piece for each cylinder cam
piece with separate bearing pieces in between. The cam and
The connecting rod is of forged alloy steel. All connecting bearing pieces are held together with two hydraulically
rod studs are hydraulically tightened. Oil is led to the tightened centre screws. The drop forged completely hard-
gudgeon pin bearing and piston through a bore in the con- ened camshaft pieces have fixed cams. The camshaft bear-
necting rod. ing housings are integrated in the engine block casting and
are thus completely closed. The bearings are installed and
4.2.4. Main bearings and big end bearings removed by means of a hydraulic tool. The original installa-
tion in the factory in done with cooling of the bearing. The
The main bearings and the big end bearings are of the Al
based bi-metal type with steel back.
camshaft covers, one for each cylinder, seal against the en- The injection pumps have built-in roller tappets and are
gine block with a closed O-ring profile. through-flown to enable heavy fuel operation. They are
The valve tappets are of piston type with self-adjustment also equipped with a stop cylinder, which is connected to
of roller against cam to give an even distribution of the the electro-pneumatic overspeed protection system.
contact pressure. The valve springs make the valve mecha- The injection valve is centrally located in the cylinder head
nism dynamically stable. and the fuel is admitted sideways through a high pressure
connection screwed in the nozzle holder. The injection
4.2.10. Camshaft drive pipe between the injection pump and the high pressure
connection is well protected inside the hot box. The high
The camshafts are driven by the crankshaft through a gear pressure side of the injection system is thus completely sep-
train. arated from the exhaust gas side and the engine lubricating
oil spaces.
4.2.11. Turbocharging and charge air
cooling 4.2.13. Exhaust pipes
The selected turbocharger offers the ideal combination of The exhaust manifold pipes are made of special heat resis-
high-pressure ratios and good efficiency at full and part tant nodular cast iron alloy.
load. The charge air cooler is single stage type and cooled
The complete exhaust gas system is enclosed in an insulat-
by LT-water.
ing box consisting of easily removable panels. Mineral
wool is used as insulating material.
4.2.12. Injection equipment
The injection pumps are one-cylinder pumps located in
the “multi-housing”, which has the following functions:
• housing for the injection pump element
• fuel supply channel along the whole engine
• fuel return channel from each injection pump
• lubricating oil supply to the valve mechanism
• guiding for the valve tappets
40 30
4.4. Overhaul intervals and In this list HFO is based on HFO2 specification stated in
the chapter for general data and outputs.
expected life times
The following overhaul intervals and lifetimes are for guid-
ance only. Actual figures will be different depending on
service conditions. Expected component lifetimes have
been adjusted to match overhaul intervals.
* The velocities given in the above table are guidance figures only. National standards can also be applied.
5.3. Trace heating • A design pressure of not less than 12 bar has to be se -
lected.
The following pipes shall be equipped with trace heating • The nearest pipe class to be selected is PN16.
(steam, thermal oil or electrical). It shall be possible to shut
off the trace heating. • Piping test pressure is normally 1.5 x the design pressure
= 18 bar.
• All heavy fuel pipes
Example 2:
• All leak fuel and filter flushing pipes carrying heavy fuel
The pressure on the suction side of the cooling water
pump is 1.0 bar. The delivery head of the pump is 3.0 bar,
5.4. Pressure class leading to a discharge pressure of 4.0 bar. The highest point
of the pump curve (at or near zero flow) is 1.0 bar higher
The pressure class of the piping should be higher than or than the nominal point, and consequently the discharge
equal to the design pressure, which should be higher than pressure may rise to 5.0 bar (with closed or throttled
or equal to the highest operating (working) pressure. The valves).
highest operating (working) pressure is equal to the setting
of the safety valve in a system. The pressure in the system • Consequently a design pressure of not less than 5.0 bar
shall be selected.
can
• originate from a positive displacement pump • The nearest pipe class to be selected is PN6.
• be a combination of the static pressure and the pressure • Piping test pressure is normally 1.5 x the design pressure
on the highest point of the pump curve for a centrifugal = 7.5 bar.
pump Standard pressure classes are PN4, PN6, PN10, PN16,
PN25, PN40, etc.
• rise in an isolated system if the liquid is heated e.g. pre-
heating of a system
Within this Project Guide there are tables attached to 5.5. Pipe class
drawings, which specify pressure classes of connections.
The pressure class of a connection can be higher than the The principle of categorisation of piping systems in classes
(e.g. DNV) or groups (e.g. ABS) by the classification soci-
pressure class required for the pipe.
eties can be used for choosing of:
Example 1:
• type of joint to be used
The fuel pressure before the engine should be 7 bar. The
safety filter in dirty condition may cause a pressure loss of • heat treatment
1.0 bar. The viscosimeter, automatic filter, preheater and • welding procedure,
piping may cause a pressure loss of 2.5 bar. Consequently • test method
the discharge pressure of the circulating pumps may rise to
Systems with high design pressures and temperatures and
10.5 bar, and the safety valve of the pump shall thus be ad-
hazardous media belong to class I (or group I), others to II
justed e.g. to 12 bar.
or III as applicable. Quality requirements are highest on
class I.
Examples of classes of piping systems as per DNV rules
are presented in the table below.
Bending radius
Stretched
Twisted
Correctly installed
*Note anyhow that SOLAS Chapter II-1 Part C Regula- They should then be located in the fuel feed line before the
tion 26 states that “Two fuel oil service tanks for each type automatic filter and in the return line after the engine. An
of fuel used on board necessary for propulsion and vital automatically opening by-pass line around the consump-
systems or equivalent arrangements shall be provided on tion meter is recommended in case of possible clogging.
each new ship, with the capacity of at least 8 h at maximum
Cooler/Heater
continuos rating of the propulsion plant and normal oper-
ating load at sea of the generator plant. This paragraph Since the viscosity before the engine must stay between the
applies only to ships constructed on or after 1 July 1998.” allowed limits stated in the Chapter for General data and
outputs, a heater might be necessary in case the day tank
Suction strainer, MDF (1F03) temperature is low. Cooler is needed where long periods of
A suction strainer with a fineness of 0.5 mm should be in- low load operation is expected since fuel gets heated in the
stalled for protecting the feed pumps. The strainer may be engine during the circulation. The cooler is located in the
either of duplex type with change over valves or simplex return line after the engine(s). LT-water is normally used as
strainers in parallel. The design should be such that air suc- cooling medium.
tion is prevented.
Leak fuel tank, clean fuel (1T04)
Circulation pump, MDF (1P03) Clean leak fuel drained from the injection pumps can be re-
The circulation pump maintains the pressure before the used without repeated treatment. The fuel should be col-
engine. It is recommended to use screw pump as circula- lected in a separate clean leak fuel tank and, from there, be
tion pump. pumped to the settling tank. The pipes from the engine to
Design data: the drain tank should be arranged continuously sloping.
• capacity to cover the total consumption of the engines Leak fuel tank, dirty fuel (1T07)
and the flush quantity of a possible automatic filter Under normal operation no fuel should leak out of the
• the pumps should be placed so that a positive static pres- dirty system. Fuel, water and oil is drained only in the event
sure of about 30 kPa is obtained on the suction side of of unattended leaks or during maintenance. Dirty leak fuel
the pumps. pipes shall be led to a sludge tank.
Pressure control (overflow) valve, MDF (1V02) Fuel feed unit
The pressure control valve maintains the pressure in the Fuel feed equipment can also be combined to form a unit.
feed line directing the surplus flow to the suction side of
the feed pump.
set point 0.4 Mpa (4 bar)
Fuel consumption meter
If a fuel consumption meter is required, it should be fitted
in the day tank feed line. In case of individual engine fuel
consumption metering is required, two meters per engine
need to be installed.
Example: A fuel oil with a viscosity of 380 mm²/s (cSt) (A) To obtain temperatures for intermediate viscosities, draw
at 50°C (B) or 80 mm²/s (cSt) at 80°C (C) must be pre- a line from the known viscosity/temperature point in par-
heated to 115 - 130°C (D-E) before the fuel injection allel to the nearest viscosity/temperature line in the dia-
pumps, to 98°C (F) at the centrifuge and to minimum 40°C gram.
(G) in the storage tanks. The fuel oil may not be pumpable Example: Known viscosity 60 mm²/s (cSt) at 50°C (K).
below 36°C (H). The following can be read along the dotted line: viscosity at
80°C = 20 mm²/s (cSt), temperature at fuel injection
pumps 74 - 87°C, centrifuging temperature 86°C, mini-
mum storage tank temperature 28°C.
Fuel oil viscosity-temperature diagram for determining the preheating temperatures of fuel oils
(4V92G0071a)
System components
1E01 Heater 1T01 Bunker tank
1F02 Suction filter 1T02 Settling tank, HFO
1P02 Feed pump 1T03 Day tank, HFO
1P09 Transfer pump, HFO 1T04 Overflow tank
1P10 Transfer pump, MDF 1T05 Sludge tank
1S01 Separator, HFO 1T06 Day tank, MDF
1S02 Separator, MDF 1T10 Settling tank, MDF
Note that settling and day tanks have been drawn separate Separator unit (1N05)
in order to show overflow pipe. They normally have com- Suction filter for separator feed pump (1F02)
mon intermediate wall and insulation.
A suction filter shall be fitted to protect the feed pump.
Filling, transfer and storage The filter should be equipped with a heating jacket in case
The filling methods of the bunker tanks depend on the off the installation place is cold. The filter can be either a du-
board facilities available. plex filter with change over valves or two separate simplex
The ship must have means to transfer the fuel from filters. The design of the filter should be such that air suc-
tion cannot occur.
bunker tanks to setting tanks and between the bunker
tanks in order to balance the ship. • fineness 0.5 mm
The amount of fuel in the bunker tanks depends on the to- Feed pump, separator (1P02)
tal fuel consumption of all consumers onboard, maximum
The pump should be dimensioned for the actual fuel qual-
time between bunkering and the decided margin.
ity and recommended throughput through the separator.
Separation The flow rate through the separator should not exceed the
maximum fuel consumption by more than 10%. No con-
Heavy fuel (residual, and mixtures of residuals and distil-
trol valve should be used to reduce the flow of the pump.
lates) must be cleaned in an efficient centrifugal separator
before entering the day tank. Design data:
HFO separator (1S01) Maximum recommended viscosity in the day tank is 140
The fuel oil separator should be sized according to the rec- mm²/s (cSt). Due to the risk of wax formation, fuels with a
ommendations of the separator supplier. viscosity lower than 50 mm²/s (cSt)/50°C must be kept at
higher temperatures than what the viscosity would require.
Based on a separation time of 23 or 23.5 h/day, the nomi-
nal capacity of the separator can be estimated acc. to the Fuel viscosity Minimum day tank
following formula: (mm²/s (cSt) at 100°C) temperature (°C)
55 80
P[kW] · b · 24[h]
Q [l/h] = 35 70
r · t[h] 25 60
*Note anyhow that SOLAS Chapter II-1 Part C Regula-
where: tion 26 states that “Two fuel oil service tanks for each type
of fuel used on board necessary for propulsion and vital
P = max. continuous rating of the diesel engine systems or equivalent arrangements shall be provided on
b = specific fuel consumption + 15% safety margin each new ship, with the capacity of at least 8 h at maximum
r = density of the fuel continuos rating of the propulsion plant and normal oper-
t = daily separating time for selfcleaning separator (usually ating load at sea of the generator plant. This paragraph
= 23 h or 23.5 h) applies only to ships constructed on or after 1 July 1998.”
The flow rates recommended for the separator and the Fuel feed unit (1N01)
grade of fuel in use must not be exceeded. The lower the A completely assembled fuel feed unit can be supplied as
flow rate the better the separation efficiency. an option.
Sludge tank, separator (1T05) This unit normally comprises the following equipment:
The sludge tank should be placed below the separators and • two suction strainers
as close as possible. The sludge pipe should be continu- • two booster pumps of screw type, equipped with
ously falling without any horizontal parts. built-on safety valves and electric motors
Fuel feed system • one pressure control/overflow valve
General • one pressurized de-aeration tank, equipped with a level
switch operated vent valve
The fuel feed system for HFO shall be of the pressurized
type in order to prevent foaming in the return lines and cav- • two circulation pumps, same type as above
itation in the circulation pumps. • two heaters, steam, electric or thermal oil (one in opera-
The heavy fuel pipes shall be properly insulated and tion, the other as spare)
equipped with trace heating, if the viscosity of the fuel is • one automatic back-flushing filter with by-pass filter
180 mm²/s (cSt)/50°C or higher. It shall be possible to
• one viscosimeter for the control of the heaters
shut-off the heating of the pipes when running MDF (the
tracing pipes to be grouped together according to their • one steam or thermal oil control valve or control cabinet
use). for electric heaters
Any provision to change the type of fuel during operation • one thermostat for emergency control of the heaters
should be designed to obtain a smooth change in fuel tem- • one control cabinet with starters for pumps, automatic
perature and viscosity, e.g. via a mixing tank. When chang- filter and viscosimeter
ing from HFO to MDF, the viscosity at the engine should
• one alarm panel
be above 2.8 mm²/s(cSt) and not drop below 2.0
mm²/s(cSt) even during short transient conditions. In cer- The above equipment is built on a steel frame, which can
tain applications a cooler may be necessary. be welded or bolted to its foundation in the ship. All heavy
fuel pipes are insulated and provided with trace heating.
Day tanks, HFO (1T03)
When installing the unit, only power supply, group alarms
The heavy fuel day tank is usually dimensioned to ensure and fuel, steam and air pipes have to be connected.
fuel supply for about 24 operating hours when filled to
maximum*. The design of the tank should be such that wa-
ter and dirt particles do not accumulate in the suction pipe.
The tank has to be provided with a heating coil and should
be well insulated.
3120
1200
Suction strainer HFO (1F06) ther of duplex type with change over valves or simplex
A suction strainer with a fineness of 0.5 mm should be in- strainers in parallel. The design should be such that air suc-
stalled for protecting the feed pumps. The strainer should tion is prevented.
be equipped with a heating jacket. The strainer may be ei-
Dt = temperature rise, higher with increased fuel viscosity Pressure control valve on the return line
To compensate for heat losses due to radiation the above (1V04)
power should be increased with 10% + 5 kW. This valve controls the pressure in the return line from the
The following values can be used: engine.
Fuel viscosity Temperature rise Leak fuel tank, clean fuel (1T04)
(mm²/s (cSt) at 100°C) in heater (°C) Clean leak fuel drained from the injection pumps can be re-
55 65 (80 in day tank) used without repeated treatment. The fuel should be col-
35 65 (70 in day tank) lected in a separate clean leak fuel tank and, from there, be
pumped to the settling tank. The pipes from the engine to
25 60 (60 in day tank)
the drain tank should be arranged continuously sloping and
Viscosimeter should be provided with heating and insulation.
For the control of the heater(s) a viscosimeter has to be in- Leak fuel tank, dirty fuel (1T07)
stalled. A thermostatic control shall be fitted, to be used as
Under normal operation no fuel should leak out of the
safety when the viscosimeter is out of order. The
dirty system. Fuel, water and oil is drained only in the event
viscosimeter should be of a design, which stands the pres-
of unattended leaks or during maintenance. Dirty leak fuel
sure peaks caused by the injection pumps of the diesel en-
pipes shall be led to a sludge tank and be trace heated and
gine.
insulated.
Design data:
• viscosity range (at injection pumps)
12...24 mm²/s (cSt)
• operating temperature 180°C
• operating pressure 4 MPa (40 bar)
Overflow valve (1V05)
This valve limits the maximum pressure in fuel line to the
engine by relieving the pressure to the return line.
System components
1E02 Heater 1V02 MDF pressure control valve
1E03 Radiator 1V04 Pressure regulating valve
1F03 Fine filter, HFO 1V05 Overflow valve
1F05 Fine filter, MDF 1V08 3-way change over valve
1F06 Suction filter, HFO 1V09 Change over valve
1F07 Suction strainer, MDF
1F08 Automatic filter
1I01 Flow meter
1I02 Viscosimeter Pipe connections
1P04 Fuel feed pump, HFO 101 Fuel inlet
1P06 Circulation pump 102 Fuel outlet
1P08 MDF pump 103 Leak fuel drain, clean fuel
1T03 Day tank, HFO 1041 Leak fuel drain, dirty fuel free end
1T04 Leak fuel tank, clean fuel 1043 Leak fuel drain, dirty fuel flywheel end
1T06 Day tank, MDF
1T07 Leak fuel tank, dirty fuel
1T08 De-aeration tank
Table 7.2. Approved system oils: lubricating oils with improved detergent/dispersant additive chemistry - heavy
fuel (C), recommended in the first place
The lubricating oils in table below, representing conven- Table 7.3. Approved system oils: lubricating oils with
tional additive technology, are also approved for use. How- conventional detergent/dispersant additive chemistry
ever, with these lubricating oils, the service intervals will
Supplier Brand name Viscosity BN Fuel category
most likely be shorter.
Esso Exxmar 30 TP 40 SAE 40 30 A, B, C
NB! Different oil brands not to be blended unless ap-
proved by oil supplier and, during guarantee time, by en- Exxmar 40 TP 40 SAE 40 40 A, B, C
gine manufacturer. Neptuno 3000
Repsol SAE 40 30 A, B, C
SAE 40
Neptuno 4000
SAE 40 40 A, B, C
SAE 40
A condensate trap shall be fitted on all vent pipes within 1 - If the engine is equipped with a dry sump and parts of the
2 meters of the engine, see drawing 4V76E2522. lubricating oil system are off the engine, these must be
Recommended size of the vent pipe after the condensate flushed in order to remove any foreign particles before
trap is NS 80 start up.
Pipe connection engine: If an electric motor driven stand-by pump is installed, this
should be used for the flushing. In case only an engine
701 Crankcase air vent DN65, ISO 7005-1, NP16
driven main pump is installed, the ideal is to use for flush-
Crankcase ventilation (4V76E2522) ing a temporary pump of equal capacity as the main pump.
The circuit is to be flushed drawing the oil from the sump
tank pumping it through the off-engine lubricating oil sys-
tem and a flushing oil filter with a mesh size of 34 microns
FROM ENGINE or finer and returning the oil through a hose and a crank-
CRANKCASE
case door to the engine sump.
The flushing pump should be protected by a suction
strainer. Automatic lubricating oil filters, if installed, must
be bypassed during the first hours of flushing.
The flushing is more effective if the lubricating oil is
heated. Furthermore, lubricating oil separators should be
in operation prior to and during the flushing.
The minimum recommended flushing time is 24 hours.
During this time the welds in the lubricating oil piping
CRANKCASE VENT should be gently knocked at with a hammer to release slag
and the flushing filter inspected and cleaned at regular in-
tervals.
Either a separate flushing oil or the approved engine oil
BILGE SLUDGE TANK can be used for flushing. If an approved engine oil is used,
it can be maintained provided that it is separated 4 - 5 times
7.8. Flushing instructions over after the flushing has been terminated and the filter
inserts remain clean from any visible contamination.
If the engine is equipped with a wet oil sump and the com-
plete lubricating oil system is built on the engine, flushing is
not required. The system oil tank should be carefully
cleaned and the oil separated to remove dirt and welding
slag.
The compressed air system of the electro- pneumatic It should be noted that the minimum pressures stated in
overspeed trip is connected to the starting air system. For the chapter for technical data assume that this pressure is
this reason, the air supply to the engine must not be closed available at engine inlet.
during operation. The rule requirements of some classification societies are
not precise for multiple engine installations.
8.4. External starting air system Starting air receiver (3T01)
The design of the starting air system is partly determined The starting air receiver should be dimensioned for a nom-
by the rules of the classification societies. Most classifica- inal pressure of 30 bar.
tion societies require the total capacity to be divided over The number and the capacity of the air receivers for pro-
two roughly equally sized starting air receivers and starting pulsion engines depend on the requirements of the classifi-
air compressors. cation societies and the type of installation.
If the inertia of the directly coupled equipment is much
larger than the normal reference equipment used on test-
bed the starting air consumption per start value has to be
increased in relation to total (engine included) inertial
masses involved.
The starting air receivers are to be equipped with a manual • The starting air pipes should always be drawn with slope
valve for condensate drainage. If the air receivers are and be arranged with manual or automatic draining at
mounted horizontally, there must be an inclination of 3-5° the lowest points.
towards drain valve to ensure efficient draining
Starting air compressor (3N02)
Recommended min. volumes of starting air vessels are:
• At least two starting air compressors must be installed. It
• Single main engine driving CPP 2 x 125 l
is recommended that the compressors are capable of fill-
• Single main engine driving FPP 2 x 125 l ing the starting air receiver from minimum to maximum
• Multiple main engines 2 x 250 l pressure in 15 - 30 minutes. For exact determination of
• 1 - 3 auxiliary engines 2 x 125 l the minimum capacity, the rules of the classification so-
cieties must be followed.
• > 3 auxiliary engines 2 x 250 l
Oil and water separator
• An oil and water separator should always be installed in
the pipe between the compressor and the air receiver.
Depending on the operation conditions of the installa-
tion, an oil and water separator may be needed in the
pipe between the air receiver and the engine.
Glycol
Use of glycol in the cooling water is not recommended. It
is however possible to use up to 10% glycol without engine
derating. For higher concentrations the engine shall be de-
rated 0.67% for each percentage unit exceeding 10.
15
Head [m ]
15
Head [m ]
10
10
5
5
0
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Flow [m ³/h]
Flow [m ³/h]
Head [m ]
15 15
10 10
5 5
0 0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
Flow [m ³/h] Flow [m ³/h]
20
15
Head [m ]
Head [m ]
15
10
10
5
5
0 0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
9.2.4. Thermostatic valve LT-circuit The lubricating oil cooler is cooled by fresh water and con-
nected in series with the charge air cooler.
(4V03)
The thermostatic valve for the LT-circuit is arranged to
control the outlet temperature of the water on engines. The
thermostatic valve has one fixed set point of 49°C with
System components
01 HT-cooling water pump
02 LT-cooling water pump
03 Charge air cooler
04 Lubrication oil cooler
05 HT-thermostatic valve
06 LT-thermostatic valve
07 Adjustable orifice
9.3. External cooling water In case of fresh water central cooler is used for both LT
and HT water the fresh water flow can be calculated with
system the following formula:
The fresh water pipes should be designed to minimize the
flow resistance in the external piping. Galvanized pipes 3.6 · F
should not be used for fresh water. q = qLT +
4.19 · (Tout - Tin)
Ships (with ice class) designed for cold sea-water should
have temperature regulation with a recirculation back to
the sea chest: where:
q[m³/h]= total fresh water flow
• for heating of the sea chest to melt ice and slush, to avoid
clogging the sea-water strainer qLT [m³/h]= nominal LT pump capacity
• to increase the sea-water temperature to enhance the F [kW]= heat dissipated to HT water
temperature regulation of the LT-water Tout = HT water temperature after engine (91°C)
Tin = HT water temperature after cooler (38°C)
9.3.1. Sea water pump (4P11)
• Pressure drop on fresh water side, max.
The sea-water pumps are usually electrically driven. The 60 kPa (0.6 bar)
capacity of the pumps is determined by the type of coolers If the flow resistance in the external pipes is high it should
used and the heat to be dissipated. be observed when designing the cooler.
• Sea-water flow acc. to cooler manufac-
9.3.2. Fresh water central cooler (4E08) turer, normally 1.2 - 1.5
The fresh water cooler can be of either tube or plate type. x the fresh water flow
Due to the smaller dimensions the plate cooler is normally • Pressure drop on sea-water side, norm.
used. The fresh water cooler can be common for several 80-140 kPa (0.8 - 1.4 bar)
engines, also one independent cooler per engine is used.
• Fresh water temperature after cooler (before engine),
Design data: max. 38°C.
• Fresh water flow see Technical Data see Technical Data
• Safety margin to be added 15% + margin for
fouling
See also the table showing example coolers with calcula-
tion data.
Type [RPM] Flow Tcw, in Tcw, out Flow Tsw, Tsw, out A B C Dry Wet [kg]
[m³/h] [°C] [°C] [m³/h] in [°C] [°C] [mm] [mm] [mm] [kg]
750 22 52.1 38 30 32 42.6 80 505 695 270 287
4L20
1000 27 54.3 38 36 32 44.3 106 505 695 275 298
5L20 1000 33 52.9 38 44 32 43.2 121 655 845 280 306
750 33 52 38 44 32 42.6 121 655 845 280 306
6L20
1000 40 53.3 38 53 32 43.5 150 655 845 288 321
750 44 52 38 59 32 42.6 156 655 845 289 323
8L20
1000 53 53.6 38 71 32 43.8 198 655 845 298 341
750 49 52.1 38 67 32 42.7 186 655 845 293 336
9L20
1000 59 53.7 38 80 32 43.8 221 905 1095 305 354
The expansion tank should compensate for volume The energy required for heating of the HT-cooling water in
the main and auxiliary engines can be taken from a running
changes in the cooling water system, serve as venting ar-
engine or a separate source. In both cases a separate circu-
rangement and provide sufficient static pressure for the
lating pump should be used to ensure the circulation. If the
cooling water circulating pumps.
cooling water systems of the main and auxiliary engines are
Design data: separated from each other in other respects, the energy is
• pressure from the expansion tank recommended to be transmitted through heat exchangers.
0.7...1.5 bar For installations with several engines the preheater unit
• volume min. 10% of the system can be chosen for heating up two engines. The heat from a
Concerning engine water volumes, see Chapter for Tech- running engine can be used and therefore the power con-
nical data. sumption of the heater will be less than the nominal capac-
ity.
The tank should be equipped so that it is possible to dose
water treatment agents. Heater (4E05)
The vent pipe of each engine should be drawn to the tank Steam, electrical or thermal oil heaters can be used.
separately, continuously rising, and so that mixing of air
Design data:
into the water cannot occur (the outlet should be below
the water level). • preheating temperature min. 60°C
The expansion tank is to be provided with inspection de- • required heating power 2 kW/cyl.
vices. Preheating pump (4P04)
9.3.5. Drain tank (4T04) Design data of the pump:
• capacity 0.3 m³/h x cyl.
It is recommended to provide a drain tank to which the en-
gines and coolers can be drained for maintenance so that • pressure abt. 80 kPa (0.8 bar)
the water and cooling water treatment can be collected and Preheating unit (4N01)
reused. For the water volume in the engine, see Technical
data (HT-circuit). A complete preheating unit can be supplied as option. The
unit comprises:
Most of the cooling water in the engine can be recovered
from the HT-circuit. • electric or steam heaters
• circulating pump
• control cabinet for heaters and pump
• one set of thermometers
tion. The fan should have a two-speed electric motor (or Engine room ventilation
variable speed) for enhanced flexibility. In addition to
• The rest of the engine room ventilation is provided by
manual control, the fan speed can be controlled by the
separate ventilation fans. These fans should preferably
engine load.
have two-speed electric motors (or variable speed) for
• The combustion air is conducted close to the enhanced flexibility.
turbocharger, the outlet being equipped with a flap for
• For very cold conditions a preheater in the system
controlling the direction and amount of air.
should be considered. Suitable media could be thermal
With these arrangements the normally required minimum oil or water/glycol to avoid the risk for freezing. If steam
air temperature to the main engine, see Chapter for opera- is specified as a heating system for the ship the preheater
tion ranges, can typically be maintained. For lower temper- should be in a secondary circuit.
atures special provisions are necessary.
• This system permits flexible operation, e.g. in port the
In special cases the duct can be connected directly to the capacity can be reduced during overhaul of the main en-
turbocharger, with a stepless change-over flap to take the gine when it is not preheated (and therefore not heating
air from the engine room or from outside depending on en- the room).
gine load.
1 Diesel engine
2 Suction louver *
3 Water trap
4 Combustion air fan
5 Engine room ventilation fan
5 Flap
6 Outlets with flaps
* Recommended to be equipped with a filter for ar-
eas with dirty air (rivers, coastal areas, etc.)
Ambient air temperature
Attenuation
25 dB (A) 35 dB (A)
DN D A B L Weight (kg) L Weight (kg)
250 700 335 120 2070 230 2870 340
300 700 395 150 2600 280 3600 400
350 850 445 180 2640 340 3640 490
400 950 495 205 3180 500 4180 670
450 1100 550 230 3440 600 4440 780
13.3. Marine exhaust emissions The IMO NOx limit is defined as follows:
E2: Diesel electric propulsion, Speed (%) 100 100 100 100
variable pitch Power (%) 100 75 50 25
Weighting factor 0.2 0.5 0.15 0.15
E3: Propeller law Speed (%) 100 91 80 63
Power (%) 100 75 50 25
Weighting factor 0.2 0.5 0.15 0.15
D2: Auxiliary engine Speed (%) 100 100 100 100 100
Power (%) 100 50 50 25 10
Weighting factor 0.05 0.3 0.3 0.3 0.1
For EIAPP certification, the “engine family” or the “en- 13.4.1.Selective Catalytic Reduction (SCR)
gine group” concepts may be applied. This has been done
Selective Catalytic Reduction (SCR) is the only way to
for the Wärtsilä 20 diesel engine. The engine families are
represented by their parent engines and the certification reach a NOx reduction level of 85-95%.
emission testing is only necessary for these parent engines. General system description
Further engines can be certified by checking documents,
The reducing agent, aqueous solution of urea (40 wt-%), is
components, settings etc., which have to show correspon-
injected into the exhaust gas directly after the
dence with those of the parent engine.
turbocharger. Urea decays immediately to ammonia
All non-standard engines, for instance over-rated engines, (NH3) and carbon dioxide. The mixture is passed through
non-standard-speed engines etc. have to be certified indi- the catalyst where NOx is converted to harmless nitrogen
vidually, i.e. “engine family” or “engine group” concepts and water, which are normally found in the air that we
do not apply. breathe. The catalyst elements are of honeycomb type and
According to the IMO regulations, a Technical File shall are typically of a ceramic structure with the active catalytic
be made for each engine. This Technical File contains in- material spread over the catalyst surface.
formation about the components affecting NOx emis- The injection of urea is controlled by feedback from a
sions, and each critical component is marked with a special NOx measuring device after the catalyst. The rate of NOx
IMO number. Such critical components are injection noz- reduction depends on the amount of urea added, which
zle, injection pump, camshaft, cylinder head, piston, con- can be expressed as NH3/NOx ratio. The increase of the
necting rod, charge air cooler and turbocharger. The catalyst volume can also increase the reduction rate.
allowable setting values and parameters for running the en-
When operating on HFO, the exhaust gas temperature be-
gine are also specified in the Technical File.
fore the SCR must be at least 330°C, depending on the sul-
The marked components can later, on-board the ship, be phur content of the fuel. When operating on MDF, the
easily identified by the surveyor and thus an IAPP (Interna- exhaust gas temperature can be lower. If an exhaust gas
tional Air Pollution Prevention) Statement of Compliance boiler is specified, it should be installed after the SCR.
for the ship can be issued on basis of the EIAPP Statement
of Compliance and the on-board inspection.
The disadvantages of the SCR are the large size and the rel- Urea consumption and replacement of catalyst layers are
atively high installation and operation costs. To reduce the generating the main running costs of the catalyst. The urea
size, Wärtsilä has together with subsuppliers developed the consumption is about 15-20 g/kWh of 40 wt-% urea. The
Compact SCR, which is a combined silencer and SCR. The urea solution can be prepared mixing urea granulates with
Compact SCR will require only a little more space than an water or the urea can be purchased as a 40 wt-% solution.
ordinary silencer. The urea tank should be big enough for the ship to achieve
The lifetime of the catalyst is mainly dependent on the fuel relative autonomy.
oil quality and also to some extent on the lubricating oil
quality. The lifetime of a catalyst is typically 3-5 years for
liquid fuels and slightly longer if the engine is operating on
gas. The total catalyst volume is usually divided into three
layers of catalyst, and thus one layer at time can be replaced,
and remaining activity in the older layers can be utilised.
14.3.3. Stopping (8N08) The shutdown is latching, and a shutdown reset has to be
given before it is possible to re-start. Naturally, before this
Normal stop of the engine the reason of the shutdown must be investigated.
The engine is stopped remotely via the ‘remote stop’ input For a single main engine installation it might be necessary
or in local control by the stop button on the engine. to arrange a 5 sec delay on the autostop functions (except
Manual stop can also be done by turning the stop lever into for overspeed) to give the possibility of overriding the
the stop position. autostop signal from the bridge and prevent the engine
There are two stop solenoids on the engine. One is built from stopping in a critical manoeuvring situation.
into the speed governor. The other one is controlling com- Overspeed protection
pressed air, which is fed to pneumatic cylinders at each fuel
injection pump, forcing the pumps to no-fuel when acti- A main engine is equipped with two independently adjust-
vated. This system is independent of the governor. The en- able switches for overspeed.
gine can be stopped by activating one or both of the • The speed switch with the lower set point (nom. RPM +
solenoids for at least 60 seconds. Emergency and safety 15%) can be connected for momentary activation of the
shut-down should activate both. electro-pneumatic stop solenoid. The speed switch is ac-
When two engines are connected to a common reduction tivated and the stop solenoid is energized only as long as
gear it is recommended that the clutches are blocked in the the speed is above the set point. When the speed has de-
“OUT” position when the engine is not running. When an creased, the stop solenoid is de-energized and the speed
engine is stopped, the clutch should open to prevent the is again controlled by the governor.
engine from being driven through the gear. At an The speed switch with the higher set point (nom. RPM +
overspeed shutdown signal the clutch should remain 18%) shall be connected with latching function in order to
closed. ensure shut-down of the engine.
‘Engine stop/shutdown output’ is always closed when the
stop signal is active. 14.3.5. Charge air shut-off valve
For a single main engine installation it might be necessary If gas detector senses combustible gas or vapour in the en-
to arrange a 5 sec delay on the autostop functions (except gine room the charge air shut-off valve must be automati-
for overspeed) to give the possibility of overriding the cally closed and engine shutdown activated. Also
autostop signal from the bridge and prevent the engine overspeed of the engine should automatically close this
from stopping in a critical manoeuvring situation. valve and activate shutdown. Since this is optional equip-
ment most commonly used in offshore installations the
14.3.4. Shutdowns (8N08) construction varies with engine type and installation and
the instructions in manuals must be followed.
The engine shall be automatically shut down in the follow-
ing cases:
• Lubricating oil pressure low (pressure switch) 14.4. Speed Measuring (8N03)
• Cooling water temperature high (temperature switch) An electronic speed measuring and monitoring system
• Overspeed (speed switch in SPEMOS) (SPEMOS) is built into the engine junction box.
The system monitors the engine speed with two pick-ups
and the turbocharger speed with a single pick-up. A 24 V
DC power supply is required for the SPEMOS.
14.6.Local instrumentation Stop of the standby pump should always be a manual oper-
ation. Before stopping the standby pump, the reason for
The engine is equipped with the following set of instru- the pressure drop must have been investigated and recti-
ments for local reading of pressures, temperatures and fied.
other parameters. Monitoring signals can be used to initiate the start of
Pressure gauges in panel on engine stand-by pumps.
14.8. Speed control (8I03) nals. This is often required in order to achieve good stabil-
ity without sacrificing the transient response. Further the
14.8.1. Main engine speed control dynamic response can easily be adjusted and optimised for
the particular installation, or even for different operating
Mechanical-hydraulic governors modes of the same engine. An electronic speed control is
The engines have hydraulic-mechanical governors with also capable of isochronous load sharing. In isochronous
pneumatic speed setting. These governors are usually pro- mode, there is no need for external load sharing, frequency
vided with a shut-down solenoid as the only electrical adjustment, or engine loading/unloading control in the ex-
equipment. ternal control system. Both isochronous load sharing and
traditional speed droop are standard features in all elec-
The idling speed is selected for each installation based on tronic speed controllers and either mode can be easily se-
calculations, for CP-propeller installations at 60 - 70% of lected.
the nominal speed and for FP-propeller installations at
about 35%. Speed droop means that the governor speed reference au-
tomatically decreases as the engine load increases. The
The standard control air pressure for pneumatically con- speed droop is normally adjusted to about 4%. This is to
trolled governors is: ensure proper load sharing between parallelling units. To
p = 0.514 * n - 14.3 compensate for the speed decrease of the plant when the
p = control air pressure [kPa] load increases, and vice versa when the load decreases, the
n = engine speed [RPM] PMS must in an outer (cascade) loop correct for the fre-
quency drift.
Governors for engines in FP-propeller installations are
provided with a smoke limiting function, which limits the Isochronous load sharing means that the governor speed
fuel injection as a function of the charge air pressure. reference stays the same, regardless of the load level. A
shielded twisted pair cable between the speed controllers is
Governors are, as standard, equipped with a built-in delay
necessary for isochronous load sharing. If the ship has two
of the speed change rate so that the time for speed accelera-
or more switchboard sections, which can be either con-
tion from idle to rated speed and vice versa is preset.
nected or separated, there must be a breaker also for the
In special cases speed governors of the electronic type can load sharing lines between each speed control.
be used.
Electronic speed control for Main Engines
14.8.2. Generating set speed control An electronic speed control is recommended for more de-
manding installations, e.g. main engine installations with
Mechanical-hydraulic governors
two engines connected to the same reduction gear, in par-
Auxiliary generator sets are normally provided with me- ticular if there is a shaft generator on the reduction gear.
chanical-hydraulic governors for remote electric speed set- The remote speed setting can be either an increase/de-
ting from e.g. a Power Management System (PMS). crease signal, or an analog 4-20mA speed reference, both
The governor is equipped with a speed setting motor for from e.g. a PCS. The rate at which the speed changes is ad-
synchronizing, load sharing and frequency control. justable in the speed controller.
The governor is also equipped with a shutdown solenoid Actuators with mechanical backup are only recommended
and an electrically controlled start fuel limiter. The syn- for single main engines. The actuator should in case of a
chronizing is operated by ON/OFF control as “increase” single main engine be reverse acting, so that the change
or “decrease” by polarity switching. Normal speed change over to the mechanical backup takes place automatically.
rate is about 0.3 Hz/s.
Electronic speed control for Diesel
Engines, which are to be run in parallel have governors
specially adapted for the same speed droop, about 4%, to
electric/Generator set
obtain basic load sharing. During load sharing and fre- An electronic speed control is always recommended for
quency control, the external load sharing system (PMS) diesel electric installations due to the sometimes strongly
must have a control deadband implemented, allowing for fluctuating power demand from the dominant consumer
an uneven load or frequency drift of 1 - 2%. (propulsion).
For an auxiliary generating set, an electronic speed control
14.8.3. Electronic speed governor can be specified as an option.
An Electronic speed control, comprising a separately Actuators with mechanical backup are not recommended
mounted electronic speed control unit and a built-on actu- for multi-engine installations.
ator, offers efficient tools for filtering speed and load sig-
• a secondary PTO from a step-up gear (generator runs // size of EDG. Allowance is also recommended for possible
propeller shaft) future additional emergency loads.
• a primary PTO from a step-up gear (generator runs // The emergency consumers comprises e.g.: emergency
engine) lighting, navigational and communication equipment, fire
alarm systems, fire and sprinkler pumps, bilge pump, wa-
• an engine free end
ter-tight doors, person lifts, steering gear.
A constant frequency shaft generator may be an alternative
Many shipowners have additional requirements with re-
in a vessel with a diesel driving a FPP.
gard to EDG-supplied services as precautionary measures
It is recommended to provide the main engines with elec- against blackout, e.g.: essential (non-emergency) auxiliaries
tronic speed governors when shaft generator installations for electric power generation and propulsion. This further
are applied in multi engine installations (twin-in/sin- loading of EDG shall of course be reflected in the EDG
gle-out). size, and a shedding system for non-emergency consumers
The SG is basically dimensioned with regard to the operat- to be provided and trip, in case the EDG should be over-
ing mode, electric load at sea and thruster (or other high loaded.
power consumer) sizes. It is not recommended to use the EDG as a harbour gener-
In the case with secondary PTO the shaft generator speed ator, ref. Solas Ch. II-1 Part D Reg. 42. 1.4 and Reg. 43. 1.4.
nrG and the gear ratio is to correspond to a suitable high
speed of the main engine, in order to have power enough to
run both shaft generator and CPP at a constant speed at 15.3.Electric power management
sea. In the manoeuvring mode the propeller cavitation can system (PMS)
be reduced, by selecting a 2-stage (speed) PTO gear en-
abling a lower main engine and propeller speed. 15.3.1.General
The main task of the electric power management (PMS) is
15.2.9.Earthed neutral
to control the generation plant and to ensure the availabil-
The vessels’ generation and distribution systems are ordi- ity of electrical power in the network as well as to avoid
nary insulated in low voltage installations as well as for blackout situations.
tankers. The PMS basically controls the starting/stopping and syn-
The network in medium voltage installations is mostly chronising of a generator to the network, frequency moni-
earthed via a high resistance connected to the generators’ toring, steady state load sharing between on-line
neutral. The rating of the earthed neutral system shall be generators, blackout starting, shaft generator, gear clutches
defined taking into account the ratings of all components and executes load tripping when the power plant is over-
of electrical equipment in the generation circuit. loaded (load shedding).
Earthed neutral options are e.g. a separate earthing trans- The main busbar is normally subdivided into at least two
former with a resistance, a low resistance earthed neutral or parts connected by bustie breakers, and the connection of
a direct earthed neutral. generating sets and other duplicated equipment shall be
The earthed neutral cabinet is normally delivered by the equally divided between the parts.
switchgear supplier and co-ordinated with the generator
supplier. 15.3.2.Control modes
The PMS is to have redundant hierarchy of control modes,
15.2.10.Emergency diesel generator the following provisions being typical:
The emergency source of electrical power shall be • automatic, independently derived signals without man-
self-contained independently from engine room systems ual intervention
with more stringent requirements as to operability when
• remote control, manually initiated
heeling and listing as well as location, starting arrangements
and load acceptance. • local control, e.g. hand or electric
The emergency diesel generator (EDG), supplying the The automatic mode is the normal operation main system.
emergency consumers required by Rules, is basically It is recommended that means is to be provided to start an
dimensioned according to worst loading case of fire fight- engine locally and to synchronise manually at the main
ing, flooding and blackout start. switchboard in case of the PMS failure. The back-up sys-
tem is recommended to be an independent operating sys-
The starting capacity of the emergency network shall be
tem, hard wired and with galvanic isolation to the main
specially considered, as the most power consuming emer-
system.
gency electrical consumer (motor) often determines the
Monitoring of the generating set operation to verify cor- The PMS controls the active (kW) load sharing over the
rect functioning by measurement or protection and super- speed governor:
visory control parameters in accordance to Class and • droop control, characteristics about 4 %
requirements are set in the chapter for Automation Sys-
tem. • isochronous load sharing, possible by means of an elec-
tronic speed governor taking care of ramping up, load
sharing and ramping down; PMS only connects the set
15.3.3. Main breaker control
and after allowance by the governor disconnects the set.
The following main breakers in the main switchboard are Active load sharing between diesel generators is normally
typically controlled from the PMS: proportional (balanced). The droop setting shall be equal
• diesel generator for all parallelling generators in order to have a propor-
• shaft generator tional load sharing.
But some feature mode options could promote an eco-
• bustie breaker
nomical and environment-friendly operation of the en-
• shore connection gines, e.g.:
• h i g h p o w er c ons ume rs , e .g.: bow th ruster, • master-topping up, i.e. master(s) with constant optimal
AC-compressor, load and a topping up set taking care of the load varia-
• emergency switchboard connection tions
• sequencing of the master-topping up units
15.3.4. Blackout start and precautionary
measures 15.3.6. Shaft generator load transfer
In case of blackout in the main switchboard (MSB) the re- The PMS controls the main engine in shaft generator (SG)
lated generating sets get a starting order and the first avail- applications giving priority to the electric generation, in-
able generating set to ‘run up’ will connect to the MSB, and cluding possible propulsion load reduction where applica-
the following units to be automatically synchronised. ble.
Precautions against failing blackout start are among oth- Operating with SG supplying the main switchboard (MSB)
ers: in parallel with the connected propulsion line, the fre-
• booster and fuel supply pumps connected to emergency quency may be unstable in rough sea, etc. It is recom-
switchboard (ES) mended to use the SG independently supplying the MSB or
part of it. If 2 SG are available e.g. in a twin-screw vessel,
• pre lubricating pump connected to ES
the MSB should be split into 2 parts, each part being sup-
• sequential re-start of essential pumps, fans and heavy plied by a dedicated SG.
consumers to achieve a loading ramp rather than big
The load transfer from/to the auxiliary diesel generator(s)
loading steps
should normally be on a short time basis, i.e. parallelling
Precautions against total loss of propulsion (diesel me- only for the time of unloading the generator(s) followed by
chanical concepts) in a blackout situation could be follow- generator breaker opening.
ing measures among others:
The shaft generator is typically supplying thruster(s) in a
• essential ME pumps are engine driven separate network during the manoeuvring mode.
• essential propulsion train pumps are gear driven In the following a typical example of load transfer at sea to
• essential electrical pumps and fans for propulsion are a running shaft generator when the thrusters have been dis-
connected to ES connected:
• operate with split network • assure that the main engine load is stable and that the
constant speed mode is selected
15.3.5. Parallelling of generators, load • synchronise the SG-section and the MSB (i.e. the auxil-
sharing iary diesel engine(s) are usually synchronised to the main
engine) and close the SG-section bustie breaker
The PMS provides automatic synchronising of auxiliary
diesel generators i.e. frequency adjustment to bring the in- • transfer load to SG by unloading the auxiliary diesel gen-
coming set into synchronism and phase with the existing erator(s) according to unloading rate
system, considering possible restrictions (e.g.: short circuit • open the auxiliary diesel generator’s breaker(s) when un-
level) regarding max number of generators allowed to be loading trip level is reached
connected to the MSB. • stop the auxiliary diesel engine(s)
15.3.7.Load dependent start/stop In order to protect the generator(s) against sustained over-
load, and to ensure the integrity of supplies to services re-
The PMS includes functions for automatic load dependent
quired for propulsion and steering as well as the safety of
start/stop of diesel generation sets. the ship, suitable load shedding arrangements shall be ar-
The start/stop limits and start order in an installation with ranged.
several parallelling generating sets are set to achieve an op-
Typical consumers that may be tripped are e.g.:
timal loading of the engines in the specific operation mode
of the vessel. The PMS calculates the network’s nominal • galley consumers
power and total generator load over a defined period of • AC-compressors
time and compares that against the load dependent • accommodation ventilation
autostart/autostop limits. The objective is to ensure that
the actual load is supplied by an appropriate number of • reduction of propulsion power
generating sets to achieve best possible energy efficiency
and fuel economy. 15.3.10.Special applications, e.g.: Auxiliary
Propulsion Drive (APD)
15.3.8.Power reservation for heavy A special application providing limited redundancy with
consumers respect to increased availability of the vessel’s propulsion
Heavy consumers may be connected to a power reserva- system is the so-called Auxiliary Propulsion Drive (APD).
tion system in the PMS, which checks if there is enough re- The principle idea of this solution is that the ship can be
serve power capacity in the network upon a start request propelled by the auxiliary generating sets, by using the shaft
from the heavy consumer. If necessary the PMS will start generator as an electric motor, in case the main engine
and synchronise the next standby unit, and gives the start (ME) is not available.
permission to the heavy consumer when the needed start- The benefit of the combined shaft generator and APD is,
ing capacity is available. among others, an increase of safety when it is used as
back-up propulsion in e. g. following operating modes:
15.3.9.Load shedding (preference tripping) • booster mode, both ME and PTO are driving the pro-
peller
Auto start function is not fast enough as blackout preven-
tion after rapid and large loss of power generating capacity, • standby mode, ME disconnected for maintenance and
e.g. after tripping of a generator. APD is connected if manoeuvring is required
• emergency mode (take me home), APD is used to propel
the ship if ME fails
ES
EE G
MSB
AE G BT ~
~
MCC
AE G
AE G
MC C
AE G BT
EE G
ME MSB ~
~
SG BT
AE G MCC
AE G
MCC
AE G
SG BT
ME
EE G
~
~
MSB/MV MSB/LV
ME G BT MCC
AC
MCC
ME G AC
PM
PM
ME G AC
MCC
BT
ME G BT
MCC
16. Foundation
16.1. General The elongation of holding down bolts can be calculated
from the formula:
Engines can be either rigidly mounted on chocks, or resil-
iently mounted on rubber elements.
Wärtsilä should be informed about existing excitations
(other than Wärtsilä supplied engine excitations) and natu-
ral hull frequencies, especially if resilient mounting is con- DL = bolt elongation [mm]
sidered.
F = tensile force in bolt [N]
Dynamic forces caused by the engine are shown in the
L i= part length of bolt with diameter D i [mm]
Chapter for Vibration and noise.
Di = part diameter of bolt with length Li [mm]
Lateral supports as shown in 2V69A0236 shall be fitted
16.2. Steel structure design against the engine block. The wedge type supports shall be
The system oil tank may not extend under the reduction lightly knocked into position when the engine is hot and
gear, if the engine is of dry sump type and the oil tank is lo- secured with a tack weld. Minimum bearing surface on the
cated beneath the engine foundation. Neither should the wedges is 80%.
tank extend under the support bearing, in case there is a The engine can be installed on either steel or resin chocks.
PTO arrangement in the free end. The oil tank must also be The chocking arrangement shall be sent to the classifica-
symmetrically located in transverse direction under the en- tion society and Wärtsilä for approval.
gine.
Steel chocks
The top plates of the engine girders are normally inclined
16.3. Mounting of main engines outwards with regard to the centre line of the engine. The
Main engines can be either rigidly mounted on chocks, or inclination of the supporting surface should be 1/100. The
resiliently mounted on rubber elements. seating top plate should be designed so that the wedge-type
steel chocks can easily be fitted into their positions. The
The foundation and the double bottom should be as stiff
wedge-type chocks also have an inclination of 1/100 to
as possible in all directions to absorb the dynamic forces
match the inclination of the seating. If the rider plate of the
caused by the engine, reduction gear and thrust bearing.
engine girder is fully horizontal, a chock is welded to each
The foundation should be dimensioned and designed so point of support. The chocks should be welded around the
that harmful deformations are avoided. periphery as well as through holes drilled for this purpose
at regular intervals to avoid possible relative movement in
16.3.1. Rigid mounting the surface layer. The welded chocks are then face-milled
Main engines are normally rigidly mounted on the seating, to an inclination of 1/100. The surfaces of the welded
either on steel or resin chocks. chocks should be large enough to fully cover the
wedge-type chocks.
The engine has 4 mounting brackets cast to the engine
block. Each bracket has a threaded hole for an M16 jacking The supporting surface of the seating top plate should be
screw and two Ø22 holes for M20 holding down bolts. machined so that a bearing surface of at least 75% is ob-
tained.
The bolt closest to the flywheel at either side of the engine
shall be made as a Ø23H7/m6 fitted bolt. All other bolts The cutout in the chocks for the clearance bolts should be
are clearance bolts. about 2 mm larger than the bolt diameter. The maximum
cut out area is 20%. Holes are to be drilled and reamed to
The clearance bolts shall be through bolts with lock nuts at the correct tolerance for the fitted bolts after that the cou-
both the lower and upper ends. Ø22 holes can be drilled
pling alignment has been checked and the chocks have
into the seating through the holes in the mounting brack-
been lightly knocked into position.
ets.
In order to assure proper fastening and to avoid bending
In order to avoid bending stress in the bolts and ensure stress in the bolts, the contact face of the nut underneath
that the bolts remain tight the contact face of the nut under the seating top plate should be counterbored.
the seating top plate shall be spotfaced.
Holding down bolts shall be long enough to ensure an
elongation DL ³ 0.25 mm when tightened.
An effective bolt length of 160 mm (between the nuts) will Resin chocks
ensure a sufficient elongation. It is recommended to fit dis- Installation of main engines on resin chocks is possible
tance sleeves with L ³ 95 according to drawing
provided that the requirements of the classification societ-
4V33F0214 under the seating top plate. M20 8.8 bolts can
ies are fulfilled.
be used. Tightening torque 390 - 430 Nm.
During normal conditions, the support face of the engine
feet has a maximum temperature of about 75°C, which
Distance sleeve (4V33F0214) should be considered when selecting the type of resin.
The total surface pressure on the resin must not exceed the
maximum value, which is determined by the type of resin
and the requirements of the classification society. It is rec-
ommended to select a resin type, which has a type approval
from the relevant classification society for a total surface
pressure of 5 N/mm² (typical conservative value is ptot<
3.5 N/mm²).
In order to assure proper fastening and to avoid bending
stress in the bolts, the contact face of the nut underneath
the seating top plate should be counterbored.
If the engine is installed on resin chocks, the seating shall
be as shown in 2V69A0236, except that the 1:100 inclina-
tion is not necessary.
When installing an engine on resin chocks the following is-
sues are important:
• Sufficient elongation of the holding down bolts
• Maximum allowed surface pressure on the resin ptot =
pstatic + pbolt
• Correct tightening torque of the holding down bolts
The elongation DL of the holding down bolts should be:
DL [mm] ³ 0.12 for a surface presure on the resin ptot £
3.5 MPa
DL [mm] ³ 0.0343 x ptot [MPa] for p tot > 3.5 MPa
The recommended dimensions of resin chocks are 140 x
410 mm. This gives gives a deadweight loading pstatic on the
resin which is presented in the table below.
Engine Dwt load P static [Mpa] Bolt tension load Pbolt [Mpa] Total load Ptotal [Mpa]
4L20 0.33 2.9 3.23
Most resin types can take at least 3.5 MPa and the bolt To ensure sufficient elongation a distance sleeve according
holding down force (pbolt) can be chosen to produce 3 MPa to drawing 4V33F0214 with L ³ 45 mm shall be fitted un-
on the resin. This corresponds to a bolt tension of 83 000 N der the seating top plate
(with recommended chock dimensions) and a tightening
torque of about 305 Nm tightening the bolts to 53% of
yield, assuming M20 8.8 bolts.
From 2V69A0237
16.3.2.Resilient mounting
In order to reduce vibrations and structure borne noise,
main engines may be resiliently mounted on rubber ele-
ments.
plying a spanner to the top hexagon (S = 19). If this is not The mounts should preferably be allowed to settle for a
possible, remove the installation load progressively until minimum of 48 hours, due to initial creeping, before lining
all buffers can be turned freely. Turn the internal buffer up pipework, etc.
counter clockwise (upwards) and re-lower the installa- The transmission of forces emitted by the engine is
tion onto the mounts. Repeat the above procedure until 10...30% when using rubber mountings compared to rigid
all buffers can be rotated freely with the full installation mounting.
load applied.
• The correct deflection of the mounts is between 4 and
10 mm depending on the weight of the generating set
16.5. Reduction gear foundations
and the selected quality of the rubber. The calculated The engine and the reduction gear must have common
compressed height of the mounts is shown in the gener- foundation girders.
ating set drawing.
• Check that the mounts are evenly compressed. The
compressed height of all mounts must be within 2.0 mm.
16.6. Free end PTO driven
Adjustments in height shall be made using machined equipment foundations
chocks. If shims are used the minimum thickness of a
The foundation of the driven equipment must be inte-
shim is 0.5 mm and only one shim per mount is permit-
grated with the engine foundation.
ted.
• Check that the seating of each mount is horizontal. This
is done by measuring the compressed height of each 16.7. Flexible pipe connections
mount on all sides. The difference must not exceed 0.5
When the engine or generating set is resiliently installed, all
mm. connections must be flexible and no grating nor ladders
Adjustments are made with wedge type chocks. may be fixed to the engine or generating set. When install-
• Set the internal buffer working clearance for each ing the flexible pipe connections, unnecessary bending or
mount: stretching should be avoided. The external pipe must be
precisely aligned to the fitting or flange on the engine. It is
• Turn the internal buffer counter clockwise (upwards) to
very important that the pipe clamps for the pipe outside the
the maximum upper position.
flexible connection must be very rigid and welded to the
• Turn the internal buffer two full turns clockwise (down- steel structure of the foundation to prevent vibrations,
wards). which could damage the flexible connection.
• Finally, tighten the nut with a torque of 300 Nm. While
doing this the top hexagon must be secured with a span-
ner
Zero load
Engine Speed Frequency Full load (MX ) Frequency Full load (M X) Zero load (MX )
(M X)
[RPM] [Hz] [kNm] [kNm] [Hz] [kNm] [kNm]
4L20 720 24 10 4.8 48 7.5 1.6
750 25 9.4 5.6 50 7.5 1.5
900 30 4.8 10 60 7.4 1.4
1000 33.3 1.5 13 66.7 7.4 1.3
5L20 900 37.5 18 4.3 75 6.2 1.7
1000 41.7 18 4.3 83.3 6.3 1.8
6L20 720 36 13 1.4 72 4.2 1.2
750 37.5 12 1.9 75 4.2 1.2
900 45 9.8 4.7 90 4.7 1.3
1000 50 7.8 6.8 100 4.7 1.3
8L20 720 48 15 3.1 96 1.7 0.7
750 50 15 3.1 100 1.7 0.7
900 60 15 2.8 120 2.2 0.7
1000 66.7 15 2.6 133.3 2.2 0.7
9L20 720 54 13 3.5 108 1.1 0.5
750 56.3 13 3.5 112.5 1.1 0.5
900 67.5 14 3.6 135 1.6 0.5
1000 75 14 3.6 150 1.6 0.5
113
109 107
100
94 104
101
99 99
90
84
80 85
70 65
74
60
50 56
40
Linear
1000
2000
4000
8000
125
250
500
63
A-w eight*
31.5
18.2.Connection to alternator
Connection engine/single bearing alternator (2V64L0071)
18.3. Flexible coupling • In case of blackout and no oil pressure the stopping of a
declutched engine is so fast that the damages are minor
The power transmission of propulsion engines is accom- even without gravity tank.
plished through a flexible coupling or a combined flexible
• The use of clutch reduces torsional stresses in elastic
coupling and clutch mounted on the flywheel. The crank- coupling while starting and stopping.
shaft is equipped with an additional shield bearing at the
flywheel end. Therefore also a rather heavy coupling can be • The clutch creates investment and maintenance costs. It
mounted on the flywheel without intermediate bearings. usually increases the length of the propulsion machinery.
The type of flexible coupling to be used has to be decided • The clutch can lead to the loss of propulsion in case of
separately in each case on the basis of the torsional vibra- automation or pressure problem.
tion calculations. • Badly adjusted clutch can cause torque peaks that cause
In case of two bearing type alternator installations a flexi- damage to elastic coupling and reduction gear.
ble coupling between the engine and the generator is re- • Dry-friction type clutch can cause smoke formation to
quired. set off the fire alarm and sparks to ignite the oil on tank
top causing engine room fire.
18.4. Clutch
The clutch is required when two or more engines are con-
18.5. Shaftline locking device and
nected to the same driven machinery like a reduction gear. brake
The clutch is also required when the engine is connected to
a reduction gear having a primary PTO. 18.5.1. Locking device
Some consideration when deciding whether to have a • A shaftline locking device is needed when the operation
clutch installed or not: of the ship makes it possible to turn the shafting by the
• In ships having more than one propeller it is possible to water flow in the propeller.
run the ship with just one propeller letting the other pro-
peller(s) to windmill. This makes it possible to save the 18.5.2. Brake
running hours of the standstill engine(s) or do mainte-
nance on them. Anyhow for safety reasons the shaft is • A shaftline brake is needed when the shaftline needs to
to be locked when working around rotating shafts in the be actively stopped. This is the case when the direction
engine. of rotation needs to be reversed.
alternative 2 (4V62L0932)
18.6.Power-take-off from the free
end
Power take off at free end alternative 1
(4V62L0931)
19.1.1.In-line engines
Engine room arrangement, generating sets (2V69C0278d)
ENGINE A B C D E F
4L20 1800 700 1200 845 1970 1270
5L20 1800 700 1200 845 1970 1270
6L20 1800 1000 1200 845 1970 / 2020 1270 / 1420
8L20 1800 1300 1200 845 2020 / 2170 1420 / 1570
9L20 1800 1300 1200 845 2170/2400 1570/1800
A = Minimum height when removing a piston
B = Camshaft overhaul distance
C = Charge air cooler overhaul distance
D = Length for the door in the connecting box, from engine block
E = Min. distance of engines dependent on common base plate
F = Width of the common base plate dependent on width of the alternator
Engine A B C D
4L20 1800 700 1200 845
5L20 1800 700 1200 845
6L20 1800 1000 1200 845
8L20 1800 1300 1200 845
9L20 1800 1300 1200 845
A = Minimum height when removing a piston
B = Camshaft overhaul distance
C = Charge air cooler overhaul distance
D = Length for the door on the connecting box, from engine block
Engine A B C D
6L20 1800 1000 1200 1010
8L20 1800 1300 1200 1010
9L20 1800 1300 1200 1010
A = Minimum height when removing a piston
B = Camshaft overhaul distance
C = Charge air cooler overhaul distance
D = Length for the door on the connecting box, from engine block
22. ANNEX
22.1.Ship inclination angles
Inclination angles at which main and essential auxiliary machinery is to operate satisfactorily (4V92C0200a)
Area
Area square m square inch square foot Area square m square inch square foot
square m 1 1550.0 10.764 square m 1 1/0.0254^2 1/(12*0.0254)^2
square inch 6.4516e-04 1 6.9444e-03 square inch 0.0254^2 1 1/144
square foot 9.2903e-02 144 1 square foot (12*0.0254)^2 144 1
Values are rounded to five meaning digits where not
accurate. Equations are accurate.
Volume
Volume cubic m l (liter) cubic inch cubic foot Imperial gallon US gallon
cubic m 1 1000 61024 35.315 219.97 264.17
l (liter) 0.001 1 61.024 3.5315e-02 0.21997 0.26417
cubic inch 1.6387e-05 1.6387e-02 1 5.7870e-04 3.6047e-03 4.3290e-03
cubic foot 2.8317e-02 28.317 1728 1 6.2288 7.4805
Imperial gallon 4.5461e-03 4.5461 277.42 0.16054 1 1.2009
US gallon 3.7854e-03 3.7854 231 0.13368 0.83267 1
Values are rounded to five meaning digits where not accurate.
Volume cubic m l (liter) cubic inch cubic foot Imperial gallon US gallon
cubic m 1 1000 1/0.0254^3 1/(12*0.0254)^3 1/0.00454609 1/(231*0.0254^3)
l (liter) 0.001 1 1/0.254^3 1/(12*0.254)^3 1/4.54609 1/(231*0.254^3)
cubic inch 0.0254^3 0.254^3 1 1/12^3 0.254^3/4.54609 1/231
cubic foot (12*0.0254)^3 (12*0.254)^3 12^3 1 (12*0.254)^3/4.54609 12^3/231
Imperial gallon 0.00454609 4.54609 4.54609/0.254^3 4.54609/(12*0.0254)^3 1 4.54609/(231*0.254^3)
US gallon 231*0.0254^3 231*0.254^3 231 231/12^3 231*0.254^3/4.54609 1
Equations are accurate but some of them are reduced in order to limit the number of decimals.
Energy
Energy J BTU cal lbf ft
J 1 9.4781e-04 0.23885 0.73756
BTU 1055.06 1 252.00 778.17
cal 4.1868 3.9683e-03 1 0.32383
lbf ft 1.35582 1.2851e-03 3.0880 1
Values are rounded to five meaning digits where not accurate.
Mass
Mass kg lb oz
kg 1 2.2046 35.274
lb 0.45359 1 16
oz 0.028350 0.0625 1
Values are rounded to five meaning digits where not accurate.
Density
Density kg / cubic m lb / US gallon lb / Imperial gallon lb / cubic ft
kg / cubic m 1 0.0083454 0.010022 0.062428
lb / US gallon 119.83 1 0.83267 0.13368
lb / Imperial gallon 99.776 1.2009 1 0.16054
lb / cubic ft 16.018 7.4805 6.2288 1
Values are rounded to five meaning digits where not accurate.
Power
Power W hp US hp
W 1 0.0013596 0.0013410
hp 735.499 1 1.0136
US hp 745.7 0.98659 1
Values are rounded to five meaning digits where not accurate.
Pressure
Pressure Pa bar mmWG psi
Pa 1 0.00001 0.10197 0.00014504
bar 100000 1 10197 14.504
mmWG 9.80665 9.80665e-05 1 0.0014223
psi 6894.76 0.0689476 703.07 1
Values are rounded to five meaning digits where not accurate.
Massflow
Massflow kg / s lb / s
kg / s 1 2.2046
lb / s 0.45359 1
Values are rounded to five meaning digits where not accurate.
Volumeflow
Volumeflow cubic m / s l / min cubic m / h cubic in / s cubic ft / s cubic ft / h USG / s USG / h
cubic m / s 1 60000 3600 61024 35.315 127133 264.17 951019
l / min 1.6667e-05 1 0.06 0.98322 1699.0 0.47195 227.12 0.063090
cubic m / h 0.00027778 16.667 1 0.058993 101.94 0.028317 13.627 0.0037854
cubic in / s 1.6387e-05 1.0171 16.951 1 1728 0.48 231 0.064167
cubic ft / s 0.028317 0.00058858 0.0098096 0.00057870 1 0.00027778 0.13368 3.7133e-05
cubic ft / h 7.8658e-06 2.1189 35.315 2.0833 3600 1 481.25 0.13368
USG / s 0.0037854 0.0044029 0.073381 0.0043290 7.4805 0.0020779 1 0.00027778
USG / h 1.0515e-06 15.850 264.17 15.584 26930 7.4805 3600 1
Values are rounded to five meaning digits where not accurate.
Temperature
Below are the most common temperature conversion for-
mulas:
°C = value[K] - 273.15
°C = 5 / 9 * (value[F] - 32)
K = value[°C] + 273.15
K = 5 / 9 * (value[F] - 32) + 273.15
F = 9 / 5 * value[°C] + 32
F = 9 / 5 * (value[K] - 273.15) + 32
Prefix
Below are the most common prefix multipliers:
T = Tera = 1 000 000 000 000 times
G = Giga = 1 000 000 000 times
M = Mega = 1 000 000 times
k = kilo = 1 000 times
m = milli = divided by 1 000
m = micro = divided by 1 000 000
n = nano = divided by 1 000 000 000
22.3.Collection of drawing
symbols used in drawings