Wärtsilä Pulse Lubricating Wärtsilä Pulse Lubricating SystemSystem

A National A National Maritime Maritime Academy Academy

ProductionProduction

The reduction from a feed rate The reduction from a feed rate of of 1.1 g/kWh (0.8 g/bhph) with the 1.1 g/kWh (0.8 g/bhph) with the existing accumulator system to existing accumulator system to a feed rate with PLS of 0.7 a feed rate with PLS of 0.7 g/kWh (0.5 g/bhph) can g/kWh (0.5 g/bhph) can generate cost savings of more generate cost savings of more than US$ 270,000 a year.than US$ 270,000 a year.This corresponds to a cost This corresponds to a cost saving of about 36 per cent for saving of about 36 per cent for cylinder lubricating oil.cylinder lubricating oil.

Reduced cylinder oil feed rates and thus reduced engine operating costs.

• Precisely timed delivery of lubricating oil to the cylinder liner surface.

• Accurately metered quantities of lubricating oil delivered to the liner surface.

• Improved distribution of cylinder oil on the liner.

The benefits of the Pulse The benefits of the Pulse Lubricating SystemLubricating System

Working principle of PLSWorking principle of PLS The key feature of the Pulse Lubricating System is The key feature of the Pulse Lubricating System is

that it delivers accurately metered, load-dependent that it delivers accurately metered, load-dependent quantities of lubricating oil to the cylinder liner quantities of lubricating oil to the cylinder liner running surface at the precise timing required. running surface at the precise timing required.

Electronic control ensures the accurate dosage and Electronic control ensures the accurate dosage and timing, with full flexibility in settings.timing, with full flexibility in settings.

The cylinder lubricating oil is sprayed as a pulse of The cylinder lubricating oil is sprayed as a pulse of multiple jets on to the liner surface from a single multiple jets on to the liner surface from a single row of lubricators arranged around the liner, each row of lubricators arranged around the liner, each lubricatorlubricator

having a number of nozzle holes. having a number of nozzle holes.

The lubricators are reliable, simple non-return The lubricators are reliable, simple non-return valves.valves.

LubricatorLubricatorThe redesigned lubricator delivers the The redesigned lubricator delivers the

pressurised cylinder oil in a compact pulse as a pressurised cylinder oil in a compact pulse as a series of jet sprays directly on to the cylinder series of jet sprays directly on to the cylinder liner surface. The lubricator sare arranged liner surface. The lubricator sare arranged around the liner in one row to ensure an around the liner in one row to ensure an excellent distribution of the cylinder oil on theexcellent distribution of the cylinder oil on the

cylinder liner. The oil is equally distributed cylinder liner. The oil is equally distributed around the circumference of the cylinder liner. around the circumference of the cylinder liner. The vertical distribution is governed by the The vertical distribution is governed by the lubricating oil injection timing as a function of lubricating oil injection timing as a function of the crank angle.the crank angle.

The numbers of lubricators and their jet sprays The numbers of lubricators and their jet sprays are adapted to the cylinder size. For the largest are adapted to the cylinder size. For the largest engines, the RTA96C and RT-fl ex96C engine engines, the RTA96C and RT-fl ex96C engine types, there are eight lubricators with each types, there are eight lubricators with each lubricator having five oil jets giving a total of lubricator having five oil jets giving a total of 40 lubricating points on the liner surface40 lubricating points on the liner surface..

The oil jet sprays are directed to separate, evenly The oil jet sprays are directed to separate, evenly distributed points on the liner surface. The distributed points on the liner surface. The lubricating oil is thereby better distributed over the lubricating oil is thereby better distributed over the liner running surface than with the existing liner running surface than with the existing accumulator system so that less oil can be used. accumulator system so that less oil can be used. With the jet sprays, there is no atomisation and no With the jet sprays, there is no atomisation and no loss of lubricating oil to the scavenge air.loss of lubricating oil to the scavenge air.

Cylinder lubricating oil is delivered under pressure Cylinder lubricating oil is delivered under pressure to the lubricators by a newly-developed dosage to the lubricators by a newly-developed dosage pump which is powered by pressurised servo oil pump which is powered by pressurised servo oil drawn from the engine’s system oil. The feed rate drawn from the engine’s system oil. The feed rate and timing are electronically controlled through a and timing are electronically controlled through a solenoid valve at the lubricator pump. There is full solenoid valve at the lubricator pump. There is full flexibility in the setting of the lubricator timing flexibility in the setting of the lubricator timing point, and volumetric metering ensures constant point, and volumetric metering ensures constant spray patterns across the engine’s load range. The spray patterns across the engine’s load range. The dosage is precisely regulated even for low feed dosage is precisely regulated even for low feed rates.rates.

It proved unnecessary to include provision in theIt proved unnecessary to include provision in the Pulse Lubricating System for variation of feed Pulse Lubricating System for variation of feed

rate with respect to Sulphur content of the fuel as rate with respect to Sulphur content of the fuel as this has proved superfluous in Wärtsilä RTA and this has proved superfluous in Wärtsilä RTA and RT-flex low-speed engines. These engines are RT-flex low-speed engines. These engines are designed so that the liner surface temperatures designed so that the liner surface temperatures are generally above the dew point over their full are generally above the dew point over their full running surface. Thus for bunker fuels with some running surface. Thus for bunker fuels with some 1.5 to 4.5 per cent Sulphur no adjustment of the 1.5 to 4.5 per cent Sulphur no adjustment of the PLS is required. PLS is required.

However, bunker fuels with less than 1.5 per cent However, bunker fuels with less than 1.5 per cent Sulphur require special provisions in terms of theSulphur require special provisions in terms of the

grade of cylinder lubricating oil and the feed rate grade of cylinder lubricating oil and the feed rate as set out in the Wärtsilä guidelines for low-as set out in the Wärtsilä guidelines for low-sulphur fuels.sulphur fuels.

Schematic of the Pulse Lubricating SystemSchematic of the Pulse Lubricating System

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Th e main components of the Pulse Lubricating System are thus:• Pulse lubricating module, consisting of a dosage pump with electronically-controlled timing Lubricators, up to eight in a single row around the cylinder liner.• Filter and measuring system• Servo oil supply unit (on RTA engines) or pressure reducing unit (on RT-fl ex engines)• Control system• Crank angle sensors, two of which one is redundant.

Each module consists of a dosage pump, a 4/2-way Each module consists of a dosage pump, a 4/2-way solenoid valve, monitoring electronics, pressure sensor solenoid valve, monitoring electronics, pressure sensor and diaphragm accumulator on a base plate. The same and diaphragm accumulator on a base plate. The same lubricating modules are used for both new building lubricating modules are used for both new building and retrofit versions.and retrofit versions.

Th e timed lubricating module feeds a Th e timed lubricating module feeds a predefined metered quantity of cylinder predefined metered quantity of cylinder oil at high speed to the lubricators at the oil at high speed to the lubricators at the precise timing ascertained by the engine precise timing ascertained by the engine control system. Each lubricating module is control system. Each lubricating module is equipped with two separate supply lines: equipped with two separate supply lines: one for cylinder lubricating oil and the one for cylinder lubricating oil and the Other for servo oil. A separate servo oil Other for servo oil. A separate servo oil supply unit is needed todrive the supply unit is needed todrive the lubricating module for RTA engines, lubricating module for RTA engines, whereas on RT-fl ex common-rail engines whereas on RT-fl ex common-rail engines the servo oil is taken from the servo oil the servo oil is taken from the servo oil common rail through a pressure reducingcommon rail through a pressure reducing

The ALM-20 (Advanced Lubricating Module) checks that the The ALM-20 (Advanced Lubricating Module) checks that the dosage pump is working correctly. The ALM-20dosage pump is working correctly. The ALM-20

communicates with the master control unit through a communicates with the master control unit through a redundant bus system, sends the signal to the 4/2-way redundant bus system, sends the signal to the 4/2-way solenoid valve and processes the data from the pressure solenoid valve and processes the data from the pressure transmitter.transmitter.

Once the Wärtsilä Engine Control System (WECS) switches Once the Wärtsilä Engine Control System (WECS) switches the 4/2-way solenoid valve in the lubricating module to the the 4/2-way solenoid valve in the lubricating module to the open position, servo oil flows to the driveopen position, servo oil flows to the drive

side of the lubricating module’s side of the lubricating module’s central piston. As the central piston is central piston. As the central piston is actuated, it feeds cylinder lubricating actuated, it feeds cylinder lubricating oil from the cylinder oil supply to the oil from the cylinder oil supply to the metering ducts and then discharges it metering ducts and then discharges it from the lubricators at high pressure.from the lubricators at high pressure.The cylinder oil is accurately supplied The cylinder oil is accurately supplied at defined positions of the working at defined positions of the working piston whose position is constantly piston whose position is constantly detected by the control system from detected by the control system from the reference signal given by the the reference signal given by the crank angle sensor.crank angle sensor.

At the end of the lubrication At the end of the lubrication work cycle, the directional valve work cycle, the directional valve in the lubricating module directs in the lubricating module directs the servo oil to the return-flow the servo oil to the return-flow side of the central piston which side of the central piston which then returnsthen returns

to its initial position. The to its initial position. The metering chamber is filled again metering chamber is filled again with cylinder lubricating oil to with cylinder lubricating oil to be ready for the nextbe ready for the next

lubricating cycle.lubricating cycle.

Servo oil supplyServo oil supply The provision of servo oil to drive the dosage pump is The provision of servo oil to drive the dosage pump is

adapted to the engine type. With RT-fl ex engines, adapted to the engine type. With RT-fl ex engines, servo oil is drawn from the engine servo oil system servo oil is drawn from the engine servo oil system through a pressure reducing valve by which the oil through a pressure reducing valve by which the oil pressure is reduced from 200 bar to 50 bar. The pressure is reduced from 200 bar to 50 bar. The reduced pressure is monitored by pressure reduced pressure is monitored by pressure transmitters which are directly connected to the transmitters which are directly connected to the alarm system, the pipes are SOLAS compliant. The alarm system, the pipes are SOLAS compliant. The reduced pressure can be adjusted and the level is reduced pressure can be adjusted and the level is shown on an analogue pressure gauge. However, a shown on an analogue pressure gauge. However, a separate servo oil supply unit is provided for RTA separate servo oil supply unit is provided for RTA engines. It includes two gear pumps, one supplying engines. It includes two gear pumps, one supplying the lubricating module with servo oil taken from the the lubricating module with servo oil taken from the main engine oil system, with the second pump as a main engine oil system, with the second pump as a stand-by. The oil supply unit also includes a pressure stand-by. The oil supply unit also includes a pressure limiting and safety valve, pressure gauge, pressure limiting and safety valve, pressure gauge, pressure sensorsensor

and shut-off valve.and shut-off valve.

PLS PLS lubricatinlubricating module g module

fitted to fitted to an engine an engine cylinder.cylinder.

Filter systemFilter systemA generously dimensioned 40-micron cylinder oil A generously dimensioned 40-micron cylinder oil

filter is arranged before the lubricating modules. filter is arranged before the lubricating modules. It effectively removes any particles of dirt It effectively removes any particles of dirt thereby ensuring reliable operation of the thereby ensuring reliable operation of the lubricating modules. A 12-litre buffer tank is lubricating modules. A 12-litre buffer tank is provided and its scaled sight glass enables provided and its scaled sight glass enables cylinder oil consumption measurements of up to cylinder oil consumption measurements of up to five litres. The buffer tank also allows the filter five litres. The buffer tank also allows the filter to be changed while the engine is running. When to be changed while the engine is running. When the filter is dirty, the integrated sensor gives a the filter is dirty, the integrated sensor gives a signal on the excessive differential pressure.signal on the excessive differential pressure.

Control and monitoring systemControl and monitoring system

Control and monitoring of the Pulse Control and monitoring of the Pulse Lubricating System is provided either by Lubricating System is provided either by signals from the WECS engine control signals from the WECS engine control system in RT-fl ex common-rail engines, or by system in RT-fl ex common-rail engines, or by a separate control unit for RTA-series engines a separate control unit for RTA-series engines based on the same system. The PLS control based on the same system. The PLS control and monitoring system has Advanced and monitoring system has Advanced Lubricating Module (ALM-20) units which Lubricating Module (ALM-20) units which communicate with the master control unit communicate with the master control unit (FCM-20) by means of a redundant bus (FCM-20) by means of a redundant bus system. All control modules have a redundant system. All control modules have a redundant power supply.power supply.

When a lubricating pulse is initiated by the When a lubricating pulse is initiated by the engine control system, the monitoring engine control system, the monitoring electronics associated with the respective electronics associated with the respective lubricator activate the 4/2-way solenoid lubricator activate the 4/2-way solenoid valve. The lubricating pulse is triggered valve. The lubricating pulse is triggered electrohydraulically as the pressure sensor electrohydraulically as the pressure sensor sends a check signal to the ALM-20. When sends a check signal to the ALM-20. When the pressure is within the programmed the pressure is within the programmed range, the local signal confirms that the range, the local signal confirms that the lubricating cycle was executed as specified. lubricating cycle was executed as specified. If, for instance, no correct lubricating cycle If, for instance, no correct lubricating cycle is ascertained owing to a fault such as a is ascertained owing to a fault such as a lubricator blockage, a shortage of lubricant, lubricator blockage, a shortage of lubricant, a lack of hydraulic drive power or a faulty a lack of hydraulic drive power or a faulty shut off –valve position, a local fault signal shut off –valve position, a local fault signal is sent to the WECS engine control system.is sent to the WECS engine control system.

Service experienceService experienceThe engine had run for 6503 hours The engine had run for 6503 hours since the PLS had been installed, since the PLS had been installed, together with new cylinder liner together with new cylinder liner and piston rings. The last 3500 and piston rings. The last 3500 running hours had been with a running hours had been with a

cylinder oil feed rate of around 0.7 cylinder oil feed rate of around 0.7 g/kWh.g/kWh.