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Q6. A. Describe how a crank pin bearing of a 2 stroke main propulsion engine is opened up for inspection;

B. Which half of the bearing is subject to greater wear?

C. What are the various causes of wear down of the bearing.

Q2. Unit injection is being widely used in many electronically controlled engines. Describe any one such system. What are its advantage compared to the conventional systems?

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)

Q4. Referring to latest developments in Turbo charger application in marine diesel engines, write short notes on the following:-

(a) Power turbines Generators.

(b) Hybrid Turbo Chargers.

(c) Electro-assist Turbo chargers.

Q3. The analysis of oil may be used as a method of monitoring the condition of the equipment that it lubricates A. Explain briefly how shore analysts might test the oil; B. State the type of information that would be expected; C. Give possible reasons for an excess of: - i. Iron, ii. Copper, iii. Antimony Iv. Tin, v. Silica

Q6. Selective catalytic Reactors (SCR) are being extensively used in marine diesel engines for the compliance of Tier-III NOx emission requirements. Explain various types of SCRs in use with particular focus on the following:-

a) High-Pressure SCRs (HPSCR) vs Low-Pressure SCRs (LPSCR)

b) SCRs with static mixers.

c) SCRs installed upstream the turbocharger(s) Vs downstream turbochargers.

Q7. During morning inspection after an overnight period of UMS operation the following changes were detected:

(a) A slight but perceptible change in engine noise

(b) An alternation in engine speed.

(c) A change in exhaust temperature spread pattern.

Explain, with reasons, the possible causes of each such changes, indicating how normal operations might be restored.

Q8. Explain the reason, why the modern camshaft-less engines are known as intelligent engines. Describe briefly, the advantages and reliability of such an engine in comparison with the conventional marine diesel engines.

Q9. (a) Explain the principles behind de-rating a ship propulsion engine and the benefits. Can a derated engine be run at full power? If yes, under what conditions?

(b) Briefly explain approved procedures for de-rating of an existing propulsion engine.