Q1. Marine diesel engines run on the diesel cycle. With the introduction of natural gas as marine fuel, Otto cycle is also employed in some engines. Explain the difference between the two cycles and elaborate on the suitability of natural gas as a fuel in such engines. (16)
Q8. Explain why the use of residual fuels for the operation of large slow speed or of medium speed engines, may be responsible for the following problems with turbocharger nozzles, shrouds and blades and how in each, the problem may be minimized:
A. Build-up of deposits.
B. Hot corrosion.
C. Erosion (16)
Q9. a). If an auxiliary diesel generator over-speeds and runs away while off the load, explain: - i. How it can be stopped,
ii. What is likely to be the reasons for the failure.
b). Give-details of what cheeks are made after the machine has been stopped:
(i) Mechanically, (ii) Electrically.
Q4. Explain each of the following:
A. Why wear down in main bearings is critical to the condition of the crankshaft and propeller shaft system.
B. Why total reliance is placed on frictional grip in conventional built up crankshaft
C. Why hole oils are given large fillets in crankpin and journals.
Q5. With reference to crankcase diaphragm glands: Explain why effectiveness deteriorates in service.
A. Describe the procedure for renewal of parts so that efficiency is restored. (6)
B. Describe how effectiveness is restored if spares are unavailable. (5)
C. Explain the functions of the upper and lower sections. (5)
Q2. A. Sketch and describe a control system for maneuvering a main diesel engine from the bridge
B. Explain how local control may be effected in case of breakdown of the control system described in 2 (A).
Q8. A. Describe the precaution necessary during the initial running-in of an Auxiliary Engine run on which is newly installed or has a major overhaul; B. Explain the possible causes of oxidation of lubricating oil. C. State the frequency with which oil samples should be taken for analysis.
Q4. How is fuel oil injected into the cylinder of a heavy oil two stroke cycle internal combustion engine and how is it ignited? Show by a timing diagram at what point of stroke injection of the fuel begins and ends. Name the engine to which your answer refers. Explain the effect of advancing the timing of injection on: i. Fuel per brake horse power hour; ii. Exhaust temperature; iii. Cylinder maximum pressure
Q9. With reference to large fabricated bed plates explain: A. With reason, why longitudinal strength and rigidity is important in spite of the contributions made by ship’s structure. B. With sketches show how the combustions loads imposed on piston and cylinder heads are transmitted to and absorbed by bed plates
Username or email address *Required
Password *Required
Note: Entering wrong username in the login form will ban your IP address immediately. Entering wrong password multiple times will also ban your IP address temporarily.
Log in
Lost your password? Remember me
No account yet?
