Small Vessel Second Engineer Exam

Questions and Answers

Explain why the air outlet from the turbocharger should be cooled before entering the diesel engine cylinder.

Cooling the air outlet reduces the temperature of the air entering the cylinder, which increases the density of the air charge and improves combustion efficiency.

Explain why the charge air cooler has fins attached to its tubes.

Fins increase the surface area for heat exchange, improving the efficiency of the cooler.

State possible reasons why the charge air cooler's performance may be reduced.

Possible reasons include blockages, fouling due to dirt or oil, or damage to the cooler itself.

Identify the component parts A-E of the timing chain section.

Components typically include sprockets, chain links, tensioners, guides, and camshaft or crankshaft gears. Signup and view all the answers

Explain the reasons why chains may elongate or slacken in service.

Chains can elongate or slacken due to wear and tear, lack of lubrication, or incorrect tension adjustments. Signup and view all the answers

Describe a procedure for manually testing the set points on a diesel generator's HT cooling water.

The procedure typically involves checking the temperature sensor readings, verifying set points against operational data, and resetting as necessary. Signup and view all the answers

Sketch a scroll type fuel pump and label the main components.

A sketch should include parts such as the scroll, inlet and outlet ports, and sealing surfaces. Signup and view all the answers

Explain how the pump sketched in part (a) may vary the end of delivery.

The pump can vary the end of delivery by changing the scroll's geometry or adjusting the speed of the pump. Signup and view all the answers

Explain the meaning of the term microbial contamination in diesel fuel.

Microbial contamination refers to the growth of bacteria and fungi in fuel, which can lead to sludge formation. Signup and view all the answers

Describe the possible problems the engine may encounter if the fuel received is contaminated with microbes.

Issues may include clogged filters, injector fouling, and engine performance degradation. Signup and view all the answers

Explain how microbial contamination can be avoided.

Contamination can be avoided by keeping storage tanks clean, using biocides, and ensuring proper fuel filtration. Signup and view all the answers

Explain the actions to be taken if microbial contamination is severe.

Severe cases may require draining and cleaning the fuel tank, replacing filters, and treating the fuel with chemicals. Signup and view all the answers

State FOUR functions of lubricating oil.

Functions include reducing friction, preventing wear, sealing gaps, and cooling engine components. Signup and view all the answers

Explain the term hydrostatic lubrication.

Hydrostatic lubrication refers to the use of a positive pressure film of lubricant to keep moving parts separated. Signup and view all the answers

Explain the term boundary lubrication.

Boundary lubrication occurs when the lubricant film is too thin, allowing direct contact between surfaces. Signup and view all the answers

State ONE advantage and ONE disadvantage of using grease as a lubricant in a plain bearing.

Advantage: Grease can provide better stickiness and protection against contamination; Disadvantage: It may not flow easily to all parts as oil does. Signup and view all the answers

Sketch the assembly of a plate type heat exchanger, labeling the main components and indicating the direction of flow.

The sketch should depict plates, seals, inlets, outlets, and flow directions. Signup and view all the answers

State the materials used for the plates and seals in a plate type heat exchanger.

Common materials include stainless steel for plates and rubber or silicone for seals. Signup and view all the answers

State the purpose of the plates being corrugated in a plate type heat exchanger.

Corrugated plates increase turbulence and improve heat transfer efficiency. Signup and view all the answers

State the purpose of tell tales in a system.

Tell tales indicate the performance or flow condition within the system, helping prevent failures. Signup and view all the answers

Describe the possible causes and remedies for low lubricating oil pressure in a diesel engine.

Causes may include low oil level, worn pump, or blocked filters; remedies involve topping up oil, replacing the pump, or cleaning filters. Signup and view all the answers

Describe the possible causes and remedies for overheating in a diesel engine.

Causes may include insufficient coolant, blockages in the cooling system, or faulty thermostats; remedies involve checking coolant levels, clearing blockages, or replacing thermostats. Signup and view all the answers

Describe the possible causes and remedies for unstable speed in a diesel engine.

Causes may include fuel contamination, air leaks, or faulty governor; remedies involve cleaning fuel lines, checking seals, or servicing the governor. Signup and view all the answers

State THREE advantages of a wet clutch.

Advantages include better cooling, enhanced grip, and the ability to use a smaller design. Signup and view all the answers

State THREE disadvantages of a wet clutch.

Disadvantages include complexity, potential for fluid leaks, and maintenance requirements. Signup and view all the answers

State ONE advantage of multiple plates in a clutch system.

An advantage is increased surface area for friction, enhancing torque transfer. Signup and view all the answers

State THREE disadvantages of multiple plates in a clutch system.

Disadvantages include increased complexity, higher manufacturing costs, and the potential for increased wear. Signup and view all the answers

Study Notes

Exam Overview

Examination on Marine Diesel Engineering held on January 20, 2023.
Duration: 1400-1600 hours.
Total marks: 100; passing mark: 50.
Non-programmable calculators allowed.
All calculations must show formulae and intermediate steps.

Turbocharger and Engine Components

Cooling air outlet: Essential to reduce temperature before entering the cylinder, preventing engine knock and improving efficiency.
Charge air cooler fins: Increase surface area for better heat exchange, enhancing cooling performance.
Charge air cooler performance issues: Possible causes include clogging, corrosion, and improper maintenance.

Timing Chain and Components

Component identification: A-E components must be recognized in the provided figure.
Chain elongation and slackening: Caused by wear, contamination, and poor lubrication; areas prone to wear include sprockets and chain links.

Diesel Generator Testing

Testing procedure: Manual evaluation of high-temperature cooling water set points must include specific criteria for alarm and shutdown.

Fuel Pump Mechanisms

Scroll type fuel pump: Sketch and label essential components; functions include fuel delivery regulation.
Delivery variation: Discuss methods by which the pump adjusts fuel output.

Diesel Engine Fuel Contamination

Microbial contamination: Defined as the presence of microbes in fuel.
Problems from contamination: Potential issues include clogged filters, injector damage, and efficiency loss.
Prevention methods: Implement filtration, maintain cleanliness, and manage storage conditions.
Actions for severe contamination: Recommended measures include fuel system cleaning and thorough inspection.

Functions of Lubricating Oil

Key functions: Includes reducing friction, cooling engine parts, sealing, and cleaning.
Lubrication types:
- Hydrostatic lubrication: uses fluid pressure.
- Boundary lubrication: occurs under low film thickness.
Grease in plain bearings: Advantage – good adhesion; Disadvantage – limited heat dissipation.

Plate Type Heat Exchangers

Assembly sketch: Must illustrate main components and flow direction.
Materials: Commonly used materials include stainless steel and rubber for plates and seals.
Corrugated plates: Serve to enhance turbulence and heat transfer efficiency.
Tell tales: Used for indicating heat exchanger performance or leak detection.

Diesel Engine Faults

Low lubricating oil pressure: Causes can include pump failure, leaks, and contaminated oil.
Overheating: Possible reasons are inadequate cooling, faulty thermostats, or blockages.
Unstable speed: Common issues linked to fuel delivery problems, engine load variations, or control system failures.

Friction Clutches

Wet clutch advantages: Provide smoother engagement, cooler operation, and better torque handling.
Wet clutch disadvantages: Increased complexity, potential for leaks, and higher maintenance needs.
Multiple plates advantages: Higher torque capacity in compact design.
Multiple plates disadvantages: Increased cost, complexity, and potential for uneven wear.

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Description

Prepare for the Small Vessel Second Engineer examination administered by the Scottish Qualifications Authority. This quiz covers key concepts in marine diesel engineering essential for certification. Test your understanding of the subject matter to gain confidence for the exam.