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Q3. With reference to turbocharger systems:

Describe how performance of the system is monitored and how the information gathered is used to assess performance; (8)

Describe the arrangements for maintaining the systems in good condition. (8)

Q1. (a) Explain why an engine may fail to start on air when the start air receiver is fully charged and the air receiver outlet to the engine is open.(10)

b) Describe how problems with air start systems may be avoided. (6)

Q8. Write a report to the engineering superintendent regarding the failure at sea of a crosshead main engine bottom end bearing. The report must explain how the defect was detected, the immediate action taken to prevent further engine damage, the subsequent action taken to ensure that the vessel was able to continue on passage to the next port, probable cause of the bearing failure and other checks made on the engine. (16)

Q6. (a) Describe a procedure for cylinder liner calibration, indicating how the readings are recorded to allow for easy recognition of liner wear. (6)

(b) Describe TWO forms of abnormal cylinder liner wear, explaining how each is recognised. (6)

(c)Explain how abnormal cylinder liner wear may be prevented. (4)

Q8. (a) With the aid of sketches, describe the operation of a dual fuel 4-stroke engine when operating on gas. (10)

(b) For the engine described in part (a), explain how and when the fuels are supplied to the cylinders (6)

Q6. With reference to two stroke, slow speed engines:

Explain what is meant by the term thermal stress and how this can cause cracking of the crown surfaces; (4)

Sketch a cross section of a piston, labelling the MAIN components and indicating coolant flow; (8)

State a cause of EACH of the following defects:

(i) Burning of the crown upper surfaces; (2)         (ii) Carbon deposits in the cooling spaces. (2)

Q7. A. Describe, with the aid of a sketch, a main engine and generator engine fuel system which has the capability of changing the generators from HFO to MDO operation whilst maintaining circulation of HFO in the main engine system. (8)

B. Write instructions for the change of the generator engines to operation on MDO whilst keeping the main engine fuel system circulated with HFO during stay in a port where fuel burning restrictions apply. (8)

Q3. A. Describe, with the aid of a sketch, a Selective Catalytic Reduction system, explaining the chemical reaction for reducing NOx and the control system requirements. (10)

B. State two engine-based systems for reducing marine diesel engine NOx, explaining how they reduce NOx level but also increase fuel consumption and CO2 emissions. (6)

Q9. Explain the possible causes and actions to be taken in the event of a high exhaust temperature on a 4-stroke generator engine at:

(i) A single cylinder (3)                            (ii) More than one cylinder (3)

Explain why multiple air inlet and exhaust valves are fitted to highly rated 4-stroke engines (4)

Describe an arrangement for operating multiple valves from a single cam, explaining how the tappet clearance is set for both valves. (6)