Failure of diesel engine

The 2-stroke marine engine is the main propulsion power source and also the biggest machinery on a ship. A great amount of efforts, resources and time is spent to ensure that this massive engine runs smoothly and efficiently, taking the ship from one port to another without breakdowns.

But no matter how many precautions are taken, problems/breakdowns are bound to take place considering the complexity and number of parts the 2-stroke marine engine has.

1. Stuck Fuel Rack: This is one of the most common problem with oil fired 2 stroke marine engines. The governor controls the fuel pump delivery through a fuel rack, which is a combination of mechanical links. Sometimes the fuel rack gets stuck leading to lack of fuel supply in the concerned unit which results in either fluctuation in the engine RPM if running or engine will not start from standstill.

Solution: All the mechanical links of the fuel rack must be well lubricated and greased before starting the main engine. If after starting the main engine, the engine rpm is constantly fluctuating even at lower speed in calm weather, check all the fuel rack as one or more of them must be stuck.

2. Starting Air Valve Leakage: Any leakage from the starting air valve will lead to hot gasses going back to the engine air line, which may contain thin oil film. Such mixture of oil and film can lead to starting air line explosion. This kind of explosion is not very common now-a-days due to safety features incorporated in the air line. However, one cannot overlook the possibility of malfunctioning of such devices which can lead to explosion.

Solution: Normally, there is no remote monitoring of temperature for the air line supplying air to starting air valve. The best way to determine such fault is to check the temperature of the air line manually during maneuvering. This problem is more likely to occur when the engine is started frequently and not when engine is running continuously.

3. Fuel Leakage/ Fuel Valve Malfunction: Problem in the fuel system are also commonly observed in the main engine. When there is a deviation in temperature of one unit, the fuel system, especially the fuel valve needs to be checked. Overhauling and pressure testing of fuel valve must be done as per PMS. If the engine is maneuvered in diesel oil, there are chances of leakage from the pump seals. Also if the fuel treatment is improper and the fuel temperature is not maintained, it can lead to cracks and leakages in high pressure fuel pipe.

Solution: Any leakage in the main engine fuel oil system can be determined from the “high pressure leak off tank” level and alarm.

4. Sparks in the Main Engine Exhaust At Funnel: Marine engineers normally experience getting a call from bridge officer informing about sparks coming out from the funnel, which is the main engine exhaust. Sparks from funnel occur due to slow steaming and frequent maneuverings, which build unburnt soot deposits on the EGB boiler path.

Solution: Frequent cleaning (monthly) of the exhaust gas boiler to be preferred by the ship staff to avoid this problem.

5. Starting Air Leakage: This is also one of the most underrated yet common problems related to marine engines. The control air supplies air to different parts and systems of the main engine. It is always in open condition when the engine is in use. Small leakages are normal and can be rectified only by tightening or replacing the pipes or joints.

Solution: When the Engine room machinery is in working condition it is difficult to hear any air leakage sound. The best way is to trace all the air lines and feeling all the connections/ joints by hand for air leakage. The easiest way to find air leakages is when there is an intentional black out done for any job. At this moment all the machinery will be in “stop” position and leakage sound (a hissing noise) will be loud and clear. Note the leakage area to perform the repairs later.

6. Stuck Air Distributor: Air distributor is responsible for maintaining the air supply which opens the starting air valve in the engine cylinders. Since it’s a mechanical part, it is prone to malfunctioning, especially getting stuck. The main engine will not start if air distributor does not supply air to open the starting air valves as no air will be present in the cylinder to commence fuel combustion

Solution: Many engines such as MAN B&W have their air distributor located at the end, with inspection cover, which can be opened when the engine is not running for inspection and lubrication to avoid this problem.

7. Malfunctioning of Installed Gauges: It is very important to have local parameter gauges on various systems of the main engine. To note down the readings in the log book, it is always recommended to take the the local readings rather than remote readings. Often engineers find that one or two gauges (pyrometer, pressure gauges, manometers etc.) installed in the main engine are not working or in dilapidated condition. The reason for such condition can be due to loose parts and connections, and even vibrations.

Solution: Replace the faulty parameter gauges with new ones as early as possible.

8. Faulty Alarms and Sensors: The main engine is fitted with various sensors, which measure and transmit actual data to alarm console. Due to factors such as vibration, high temperature, humidity, dust etc. these sensors can malfunction leading to false alarms.

Solution: A routine checks needs to be performed on all engine room sensors and alarms. Different main engine safety alarms and trips also to be tried out at regular basis and faults to be attended immediately.

Exercise 6. Answer the following questions.

1. Describe all the possible problems with 2-stroke diesel engine.

2. Describe all the solutions to these problems.

3. What is the most common malfunction? How can you escape it?

Watch the video “Diesel Engine Maintenance: Preventing Catastrophic Engine Failure” and discuss the following topics.

[https://www.youtube.com/watch?v=qEyhsk0JTOo]

1. The lube oil changing

2. Refilling with fresh lube oil.

3. Piston examination.

TEST YOURSELF

TEST 1

1. What is a purpose of cylinder head safety valve?

1. A valve for safety stop (emergency) of the engine

2. For indication of engine being overloaded

3. To relieve high pressure in the cylinder to protect the engine from being damaged

4. To adjust the cylinder pressure to a safe working pressure.

2. The starting air valve is fitted for the purpose of:

1. Tuning the engine for staring preparations

2. To retard the engine revolution for maneuvering purpose

3. Bringing the engine up to full rpm to start the engine

4. Bringing the engine up to sufficient number of revolutions for combustion take place and engine to run.

3. When the temperature of lubricating oil is lowered, an increase will occur in:

1. Viscosity

2. Flash point

3. Pour point

4. Concentration of contaminants

4.During operation of the main engine, the heat absorbed by lubricating oil is removed by the:

1. Scavenge air cooler

2. Sump vents

3. Lube oil cooler

4. Any of the above

5. An excessive pressure drop across a lube oil strainer could indicate:

1. Any of the above

2. That the strainer is ok

3. That the strainer needs cleaning

4. That a relief valve is stuck open

6.Why is it important to keep the lub oil viscosity within safe limits?

1. To keep the oil protective film between moving metal surfaces

2. It is not important

3. To keep the additives in good condition

4. The lub oil has no influence on the oil’s lubrication ability

7.What could be the reason if the lub oil viscosity increases?

1. Heavy fuel oil leakage to the lub oil system

2. Water leakage to the lub oil system

3. The lub oil viscosity will not increase

4. High lub oil temperature

8.What could be the reason if the lub oil viscosity decreases?

1. Heavy fuel oil leakage to the lub oil system

2. Low lub iol temperature

3. Wrong lub oil pressure

4. Diesel oil leakage to the lub oil system

9.What are the compartments to be regularly checked with regard to water and oil leakages?

1. Tank top in the engine room

2. Bilge wells

3. Bilge tank(s)

4. All those listed in the other alternatives.

10.During standstill liquid may condense in the crankcase or oil separator. Why is it important to heat up the oil before start?

1. The compressor will run better

2. Compressor oil regulating system will operate better

3. To avoid the compressor oil to disappear from the crankcase during starting

4. It should never be done.

TEST 2

Answer "False" or "True".

1. Both relieving and being relived engineers should make a joint inspection round.

2. If the temperature of the generator stator or rotor increases suddenly or exceeds the prescribed limits the watch engineers are to call the chief engineer.

3. "Defects caused by vibration" are one of the general classes of derangements likely to occur in operation of engines.

4. As a concept, diesel electric propulsion (DEP) is not a new system.

5. Steam engine alone is a usable machine.

6. I.H.P. means Introduced horsepower.

7. In general the bearing pressures are higher in the Diesel than in the steam engine.

8. In tropical harbors the sea suction may be gripped by a jellyfish.

9. Each ship has just one sea suction.

10. Cracks in cylinders may result from unequal heating due to poor design, bad castings or air pockets in jackets.

11. Cargo or bunker tanks which have been topped up should be checked frequently during the loading operations to avoid an overflow.

12. Pollution can come from engine room bilges of all ships (not only tankers).

Keys to test 1: 1-b; 2-d; 3-a; 4-c; 5-c; 6-a; 7-a; 8-d; 9-d; 10-c.

Keys to test 2: 1-true; 2-true;3-false;4-true;5-false;6-false;7-true;8-false;9-false;10-true;11-true;12-true.

ПРИЛОЖЕНИЕ

Synonyms

недостаток

default

defect

deficiency

disadvantage

drawback

fault

failure

fuisance

weakness

иметь цель, ставить целью

to aim

to be concerned

to be directed

to be intended

to comprise

частично устранить недостаток

to improve

to lessen

to mitigate

to overcome

to reduce

to relieve

устранить недостаток

to cure

to deal with

to do away with

to eliminate

to get rid of

to improve

to remedy

to overcome

to solve

to surmount

cпециалист

an engineer

a skilled person

a worker in this field

one acquainted with

one familiar with the art

one skilled in the art

cинонимы к слову «относиться»

to be concerned with

to deal with

to be directed to

to be related to

to be relevance to

to pertain

to refer to

to absorb / to take up поглощать

to acknowledge / to confirm / to affirm подтверждать

accumulation / pilling / assemblage накопление, аккумуляция

to be apt / to be possible быть возможным

to be attached / to be fitted быть присоединенным

avoidance / evasion избежание

being relieved / offgoing механик, которого сменяют

to bind / to grip заедать

to be engaged / involved in заниматься чем-либо

complicated / complex сложный

derangement / fault / malfunction неполадка.

design / construction конструкция

to develop / to evolve / to expand развивать, расширять

to discharge / to use up / to run down разряжать

disrepair/failure плохое состояние, неиспраность

distinct / definite / plain явный, определенный

donkey boiler / auxiliary boiler вспомогательный котел

to enter into force / to come into force / to take effect вступать в силу

to familiarize / to acquaint (with) ознакомиться

frequent / rapid частый, повторяющийся

garbage / waste / refuse мусор

to grease / to lubricate смазывать

ground / basis / cause основание

hazard / danger угроза, опасность

to immerse / to plunge / to submerge погружаться в воду

impart / relate / disclose сообщать, передавать

implementation / execution / performance осуществление, выполнение

to investigate / to consider / to examine рассматривать, расследовать

in the vicinity / nearby по близости, в районе

to lift / to heave / to raise поднимать

looseness / slackness неплотность (крепления)

to lubricate / to smear / to oil смазывать

moisture / humidity / dampness влажность

objective / aim / goal цель

to occur / to happen возникать, случаться

to plug up / to clog / to obstruct засорять(ся)

rapid / prompt / fast быстрый

rare / uncommon / scarce редкий

reasonable / acceptable / admissible приемлемый

to refine / to purify / to clarify очищать

relieving engineer / oncoming сменяющий механик

to reveal / to show показывать, раскрывать

to rotate/revolve вращаться

to run off / flow down / trickle down стекать

probability / likelihood вероятность

shoal / shallow water мелководье

thoroughly / fully / completely полностью

tightness / seal плотность, герметичность

to top up / to fill up / to add доливать

volume/ capacity / bulk емкость, вместимость

БИБЛИОГРАФИЧЕСКИЙ СПИСОК

1. Борецкий В.В. Методические указания к практическим занятиям по дисциплине «Английский язык» для студентов III -IV курсов специальности «Эксплуатация судовых энергетических установок» дневной формы обучения (часть II) / В.В. Борецкий, Ю.А. Мороз, В.А. Стеценко. – Севастополь: Изд-во СевНТУ, 2007 – 64 с.

2. Китаевич Б.Е. Морские грузовые операции: Учебное пособие по английскому языку / Б.Е. Китаевич, А.И. Короленко, М.Л Калиновская. – М.: Росконсульт, 1999. – 160 с.

3. Писарева Л.П. Английский язык. Сборник текстов и упражнений для старших курсов специальности «Эксплуатация судовых энергетических установок» очной и заочной форм обучения / Л.П. Писарева. – Петропавловск-Камчатский: КамчатГТУ, 2006. – 92с.