EKM-Oct-2020

Q1. (a) Describe, with aid of sketches, either an electronic governor or a hydraulic governor. 
(b) Explain how the governor. described in Q.1(a), functions in order to increase fuel to the engine in the event of a load increase. 
(c) State the defects which can impair operation of the governor described in Q. 1(a)

Q2. Fatigue is one of the main causes of crankshaft failure. A. Indicate on a Sketch the most likely location of a fatigue crack; B. How is a fatigue failure identified; C. Describe initiation of a fatigue crack; D. Sketch and Describe the methods used to inhibit fatigue cracks.

Q3. A. Explain the possible reasons T/C vibration while operating at a steady speed; 

B. State how the incidence of turbo charger vibration might be minimized; C. Explain the action to be taken in order to maintain 2 stroke engine operation in the vent of turbo charger having to be taken out of service; 

D. Indicate the effect this action will have on engine operation.

Q4. A. Briefly describe the causes and effects of bacterial attack on diesel engine lubricating oil. 

B. Bacterial activity has been detected in the lubricating oil of the main engine fitted in the ship aboard which you are serving as 2ndeng. Write a letter to the owner operator of the ship indicating the action you intend to take and offer suggestion to the avoidance of future incidents.

Q5. With respect to scavenge fires in Large two stroke Marine engines: 

A. State the common causes of scavenge fires. 

B. List the indication that a scavenge fire is in progress. 

C. State the immediate action to be taken in the event of a scavenge fire. 

D. List with reasons the checks and precautions necessary before an engine is put back in to service following a scavenge fire.

Q6. With respect to Air starting systems for 2 strokes diesel engines: A. Sketch and describe Main engine starting air distributor. B. List the safety devices and interlocks incorporated in main engine air starting system and state the purpose of each.

Q7. A. Sketch a fuel injector; B. Explain how it operates and what determines the point at which injection occurs; C. Describe the defects to which fuel injectors are prone; D. How can fuel injection be improved when a low speed engine is to operate at prolonged low load.

Q8. A. Describe how a main engine fuel pump would be set and checked for: (i) Timing; (ii) Quantity B. Explain how a setting of a variable injection timing fuel pump is checked and adjusted. C. State why it be necessary to adjust the settings of a variable injection timed fuel pump.

Q9. With reference to timing chains: 

A. State the cause of chain elongation in service, using a sketch of a section of a camshaft roller chain to illustrate your answer; 

B. State: i. The effects of increased chain length: ii. The method of assessing percentage increase in length: 

C. Explain how the effects of elongation are corrected: 

D. State why a limit is placed on percentage chain elongation and give typical example.