Systems (Unfinished) Flashcards
State the purpose of the Major Components shown in the sketch (Jacket Water System)
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Describe testing of a Fuel Injector after overhaul and before it is refitted to the engine
- Visually examine the injector
- Connect injector to a testing rig
- Pump the injector up to pressure and ensure it opens at the correct bar
- Spray pattern test can now be done which ensures the fuel will be atomized and distributed correctly into the fine droplets needed
- Leakage Test can also be preformed which basically ensures that there is no fuel dribbling from the injector nozzle at any given time, especially when it is meant to be closed
State the stages of onboard preparation of heavy fuel oil prior to use
1), Fuel is transferred from the bunker tank to the settling tank.
2), Fuel oil is held and heated (Usually via Steam Coils) within the settling tank where sludge and water are separated from the oil via gravity.
3), As the fuel leaves the settling tank, further heating takes places after it travels through course filters.
4), The fuel is then heated even further before being passed through a Centrifugal Separator.
5), The Centrifugal Separator spins the fuel at a very high speed/revolutions forcing water and impurities to the peripheral of the bowl and off to waste.
6), The purified fuel is then transferred to the service tank, where it is maintained at a high temperature suitable to be used for injection.
7), When the engine is in need of fuel it is then transferred through Visco-therm where the fuel is heated to the correct viscosity for the fuel injectors.
8), The fuel then passes through the booster pumps to the main engine fuel rail.
9), Finally, the fuel passes through the fuel pumps on the main engine and is pumped to a high pressure to allow for the fuel injectors to operate and inject the fuel into the cylinder.
With reference to a Steam Heating Coil in a Fuel Tank Developing a Leak, State how the leak would be detected
- Oil or fuel seen in the seen in the Observation Tank
- Excess water found in settling or service tank
- Oil contamination in the hot well or boiler water gauge glass
- Oil sensor alarm in the condensate return system
With reference to a Steam Heating Coil in a Fuel Tank Developing a Leak, State the immediate action to be taken when the leak is detected
- Stop feed water supply to the boiler immediately to prevent further contamination
- Check the hot well for oil or fuel contamination
- ## IF FOUND, isolate the hot well and shut down the boiler immediately
With reference to a Steam Heating Coil in a Fuel Tank Developing a Leak, Explain how the leak can be traced
1), Review the ER Log Book to see if any of the steam heating coils have been recently turned on, this helps identify which coil might be involved
2), Close the Steam Inlet Valve, which stops steam from entering the coil preventing the leak from continuing
3), Close the Condensate Return Valve, which isolates the system preventing the contaminated condensate from spreading
4), Allow the System to Cool Down, which slows the leak and makes it safer for inspection
5), Open the Condensate Drain Valve, which will drain condensate to check for oil or fuel contamination
With reference to High Viscosity Fuel Oil, Explain how it is treated between storage tank and main engine
1), Fuel is transferred from the bunker tank to the settling tank.
2), Fuel oil is held and heated (Usually via Steam Coils) within the settling tank where sludge and water are separated from the oil via gravity.
3), As the fuel leaves the settling tank, further heating takes places after it travels through course filters.
4), The fuel is then heated even further before being passed through a Centrifugal Separator.
5), The Centrifugal Separator spins the fuel at a very high speed/revolutions forcing water and impurities to the peripheral of the bowl and off to waste.
6), The purified fuel is then transferred to the service tank, where it is maintained at a high temperature suitable to be used for injection.
7), When the engine is in need of fuel it is then transferred through Visco-therm where the fuel is heated to the correct viscosity for the fuel injectors.
8), The fuel then passes through the booster pumps to the main engine fuel rail.
9), Finally, the fuel passes through the fuel pumps on the main engine and is pumped to a high pressure to allow for the fuel injectors to operate and inject the fuel into the cylinder.
State the purpose for treatment of High Viscosity Fuel Oil between storage tank and main engine
HEATING OF THE FUEL
- This reduces viscosity, making it easier to handle and also allows for proper atomization for proper combustion.
+ If not heated the fuel will be far to viscus for the fuel injectors to atomize allowing for very poor combustion.
PURIFICATION
- Which is done via a Centrifugal Purifier which removes any water and solid impurities that may be contained within the oil.
+ The fuel is conditioned this way to avoid damage to engine components (corrosion or wear to engine components such as fuel injectors)
Describe Heavy Fuel Oil system from settling tank to fuel injector of the main engine
1), Fuel is transferred from the bunker tank to the settling tank.
2), Fuel oil is held and heated (Usually via Steam Coils) within the settling tank where sludge and water are separated from the oil via gravity.
3), As the fuel leaves the settling tank, further heating takes places after it travels through course filters.
4), The fuel is then heated even further before being passed through a Centrifugal Separator.
5), The Centrifugal Separator spins the fuel at a very high speed/revolutions forcing water and impurities to the peripheral of the bowl and off to waste.
6), The purified fuel is then transferred to the service tank, where it is maintained at a high temperature suitable to be used for injection.
7), When the engine is in need of fuel it is then transferred through Visco-therm where the fuel is heated to the correct viscosity for the fuel injectors.
8), The fuel then passes through the booster pumps to the main engine fuel rail.
9), Finally, the fuel passes through the fuel pumps on the main engine and is pumped to a high pressure to allow for the fuel injectors to operate and inject the fuel into the cylinder.
State the possible effects on the engine if the jacket water temperature is maintained at its optimum value
JACKET WATER TOO LOW
- Cold temperatures before the engine were to start up, it may suffer from thermal shock resulting in serious damage to engine components.
- Cold temperatures can reduce the viscosity of lubricants within the engine which can impair its ability to lubricate properly.
- Cold temperature can lead to condensate within the engine which in turn will eventually cause cold corrosion.
JACKET WATER TOO HIGH
- High temperatures can cause uneven expansion of metal components leading to thermal stress and cracking.
- High temperatures can result in lubrication in the cylinder being burnt off causing excessive sudden wear.
- High temperature can break down lube oil and fuel oil potentially causing sludge build up.
i) Define the term Viscosity
ii) Define the term Viscosity Index (VI)
iii) Define the term Pour Point
iv) Define the term Flash Point
i) A fluids resistance to flow
ii) Indicates how viscosity changes with temperature
iii) The lowest point at which oil can still flow
iv) The lowest temperature at which oil vapours ignite
Describe FOUR important characteristics of Lubricating Oil
1), Detergency - Keeps engine parts clean by removing dirt and preventing deposits.
2), Neutralizing Ability (TBN) - Helps fight acid build up in the engine to prevent corrosion.
3), Thermal Stability - Resists breaking down at high temperatures.
4), Anti-wear Properties - Protects moving parts from rubbing and wearing out.
+), Viscosity Stability - Maintains proper flow at different temperatures.
State FOUR important additives found in Lubricating Oil
1), Anti-wear Additives - Reduce component wear
2), Oxidation Resistance - Prevents sludge formation
3), Detergents - Keeps engine parts clean
4), Viscosity Index Improvers - Maintain stable viscosity across temperatures
Explain why cooling is necessary
- Prevents overheating
- Reduces wear
- Maintains efficiency
State the purpose of the Jacket Water Heater
KEEPS THE COOLANT WARM
- Quick starting of engine without thermal shock.
- Reduces wear by keeping engine components at operating temperature.
+ Prevents condensation inside the engine, which would lead to corrosion.
State the purpose of the Jacket Water Drain Tank
- Collects drained cooling water from the engines jacket system during maintenance or shutdown of main engine.
- Prevents loss of treated water by storing it for reuse.
- Allows an inspection of the drained water for contamination.
State the purpose of the Jacket Water Header Tank
ACTS AS A RESERVOIR
Maintains System Pressure - Ensures there is a positive pressure in the cooling system to prevent boiling and cavitation.
Allows Expansion - Provides space for thermal expansion of water as it heats up.
+ Helps Remove Air - Positioned at the highest point to allow air/gas to escape from the system, preventing air lock.
Explain how high viscosity fuel oil is treated prior to entering the main engine
1), Fuel is transferred from the bunker tank to the settling tank.
2), Fuel oil is held and heated (Usually via Steam Coils) within the settling tank where sludge and water are separated from the oil via gravity.
3), As the fuel leaves the settling tank, further heating takes places after it travels through course filters.
4), The fuel is then heated even further before being passed through a Centrifugal Separator.
5), The Centrifugal Separator spins the fuel at a very high speed/revolutions forcing water and impurities to the peripheral of the bowl and off to waste.
6), The purified fuel is then transferred to the service tank, where it is maintained at a high temperature suitable to be used for injection.
7), When the engine is in need of fuel it is then transferred through Visco-therm where the fuel is heated to the correct viscosity for the fuel injectors.
8), The fuel then passes through the booster pumps to the main engine fuel rail.
9), Finally, the fuel passes through the fuel pumps on the main engine and is pumped to a high pressure to allow for the fuel injectors to operate and inject the fuel into the cylinder.
State the changes in the fuel preparation required when changing fuel of a lower density and viscosity
- Smaller Gravity Disk in Purifiers - Changing to a smaller disk helps separate water and oil properly when using lower densities and viscosity fuel.
- Finer Filters - Finer filters help remove particles more effectively from the fuel.
- Adjusting the Visco-therm Controller - The controller should be set to avoid overheating the fuel, which can reduce its viscosity too much and cause issues.
- Retarding Fuel Injection Timing - The engine fuel injection timing needs to be adjusted to account for the fuel being less viscous, ensuring proper combustion.
Describe the procedure to change the fuel supply of the main engine from high viscosity to low viscosity fuel such as diesel oil
1), Reduce Engine Load - Which in turn lowers fuel consumption and makes it easier for the system to stabilize during the switch.
2), Change over HFO feed to D/O feed - Gradually switch from HFO to D/O, making sure the change happens slowly to avoid any pressure issues.
3), Allow D/O to Circulate - Allow the D/O to mix with any remaining HFO and flow evenly through the system.
4), Take Control of the Visco-therm - Lower the fuel temperature gradually (aim for 2 degrees per minute) to control viscosity and prevent overheating or gassing.
5), Monitor - The changeover should take approximately 1 hour, gradually switching helps prevent air bubbles or pressure spikes in the fuel system.
6), The viscosity will slowly drop as the fuel begins to cool but the D/O will drop to the correct level for engine use.
State the precautions to be taken against spillage during bunkering operations
1), All scuppers and drip trays are closed to prevent any accidental spillage from flowing into the sea.
2), Vents are clear and properly functioning to allow safe and free flow of the fuel without pressure build-up during bunkering.
3), SOPEP equipment including absorbents and booms must be readily available near the bunkering area in case of spillage.
4), Clear communications must be established with the bunker barge to coordinate the operation and quickly respond.
5), Bunker hose must be secure to prevent it from moving or disconnecting, reducing risk of spillage.
6), Fuel filling pressure must be kept within the recommended limits to avoid overfilling or leakage.
7), Fuel tank levels must be frequently monitored ensuring they are not overfilled and to detect any irregularities such as change of flow rate, pressure fluctuations etc.
8), Ensure all crew members are familiar with their roles in responding to a potential spillage.
9), Know the emergency stop signal between the ship and bunker barge in case of oil spillage.
Describe the procedure to change the fuel supply system of the main propulsion engine for High Viscosity Fuel to Low Viscosity Fuel such as diesel oil whilst on passage
1), Reduce Engine Load - Which in turn lowers fuel consumption and makes it easier for the system to stabilize during the switch.
2), Change over HFO feed to D/O feed - Gradually switch from HFO to D/O, making sure the change happens slowly to avoid any pressure issues.
3), Allow D/O to Circulate - Allow the D/O to mix with any remaining HFO and flow evenly through the system.
4), Take Control of the Visco-therm - Lower the fuel temperature gradually (aim for 2 degrees per minute) to control viscosity and prevent overheating or gassing.
5), Monitor - The changeover should take approximately 1 hour, gradually switching helps prevent air bubbles or pressure spikes in the fuel system.
6), The viscosity will slowly drop as the fuel begins to cool but the D/O will drop to the correct level for engine use.
explain, with the aid of a sketch, how the jacket water temperature is maintained at its optimum value
INCLUDES SKETCH
- Jacket water temperature is maintained with the use of a cooler and 3 way valve.
- Temperature sensor sends signals to a controller, which then adjusts the 3 way valve to maintain set temperature.
+ In port, a heater keeps the engine warm.
