Question

(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. (6)

(b) Explain the possible causes of oxidation of lubricating oil. (5)

(c) State the frequency with which oil samples should be taken for analysis. (5)

Answer 1

Part (a)

Precautions necessary during the initial running-in of an Auxiliary Engine:

Use a low TBN oil in the sump.
Initially start the engine on DO, then change over to HFO but do not take load.
Allow the engine to run at no load for the time specified by the Maker.
Maintain a lower jacket cooling water (JCW) temperature so that the maximum wear rate is achieved and asperities are broken.
After the no-load running period, gradually take on load step by step as per Maker’s instructions, while carefully monitoring all pressures and temperatures.
Use the recommended lubricating oil after reaching 30% of the load.
Follow the Maker’s recommendations at all times.
With the help of a temperature gun, check crankcase temperatures to detect any sign of blow-past.

Part (b)

Possible causes of oxidation of lubricating oil:

Reduced total oil quantity in sump, leading to high circulation rate (15–18 times/hr), thus insufficient time for deaeration.
Excessive wear down of components, as particles like Cu, Fe and rust act as catalysts for oxidation.
Thermal breakdown of oil due to insufficient cooling.
Presence of varnish and lacquer in the system.
Contamination of lubricating oil with dirt or water.

✓ Verified Model Answer (Text Solution)

Precautions necessary during the initial running-in of an Auxiliary Engine:

Possible causes of oxidation of lubricating oil: