Marine Diesel Engineering Exam - SQA Small Vessel Second Engineer 060-01

To increase the density of the air and improve combustion efficiency

To increase the heat transfer rate

Possible reasons include fouling, corrosion, or leakage

Component A: Sprocket, Component B: Chain guide, Component C: Timing chain, Component D: Tensioner, Component E: Crankshaft gear

Chains may elongate due to wear between the pins and bushings, while slackening can occur due to tensioner wear. Areas that may wear include the pins, bushings, and rollers.

The procedure involves checking the set points, simulating high temperatures, and verifying the alarm and shut down responses.

The pump can vary the end of delivery by adjusting the timing of the fuel injection process.

Microbial contamination refers to the presence of microorganisms, such as bacteria, fungi, or algae, in the diesel fuel.

If the fuel is contaminated with microbes, the engine may encounter problems such as clogged fuel filters, fuel line blockages, and corrosion of fuel system components.

Microbial contamination can be avoided by using clean fuel storage tanks, regularly cleaning the fuel system, and adding biocides or fuel stabilizers to the fuel.

If microbial contamination is severe, the fuel system should be thoroughly cleaned, the fuel filters replaced, and the fuel tank drained and refilled with clean fuel.

The four functions of lubricating oil in a diesel engine are: 1) Reducing friction and wear, 2) Cooling engine components, 3) Cleaning and removing contaminants, and 4) Sealing engine components.

(i) Hydrostatic lubrication refers to a lubrication regime where a thick film of oil completely separates the moving surfaces, minimizing direct contact and friction. (ii) Boundary lubrication occurs when the oil film is too thin to fully separate the surfaces, and some direct contact between the surfaces takes place.

Advantage: Grease can provide better sealing and prevent the ingress of contaminants into the bearing. Disadvantage: Grease may not dissipate heat as effectively as liquid lubricants, leading to increased operating temperatures.

The main components of a plate-type heat exchanger are the corrugated plates, the gaskets or seals, and the inlet and outlet ports. The flow of the two fluids should be indicated as counter-current or parallel, depending on the design.

Possible causes: 1) Worn or damaged oil pump, 2) Clogged oil filters, 3) Leaks in the oil system. Remedies: 1) Replace the oil pump, 2) Clean or replace the oil filters, 3) Inspect and repair any oil leaks.

Advantages: 1) Better heat dissipation, 2) Smoother engagement, 3) Longer service life. Disadvantages: 1) More complex design, 2) Increased maintenance requirements, 3) Potential for fluid leaks.

Advantage: Multiple plates can increase the overall surface area for friction, allowing for greater torque transmission. Disadvantage: The use of multiple plates can increase the overall size and complexity of the clutch system.