Class 1 (Chief Engineer) Engineering Management 📅 Apr 2021

Exam Question

To operate engines in compliance with the new IMO 2020 sulphur limits and to prepare the engine and auxiliaries for the changes in fuel characteristies, is a challenge for owners, operators and crews. From the Chief Engineer's perspective. Explain the following briefly:

(a) Cylinder lubrication strategies.

(b) Compatibility issues between fuel bunkered at different ports.

Reference Answer

### (a) Cylinder Lubrication Strategies
From a Chief Engineer's perspective, managing cylinder lubrication for IMO 2020 compliant fuels involves a multi-faceted strategy focused on preventing both corrosive and abrasive wear.
1. **Base Number (BN) Management:** The primary function of cylinder oil is to neutralize the sulfuric acid formed during the combustion of sulphur-containing fuels.
* **Principle:** The BN of the cylinder oil must be matched to the fuel's sulphur content. High Sulphur Fuel Oil (HSFO) requires high-BN (70-100) oil. Very Low Sulphur Fuel Oil (VLSFO) or Ultra Low Sulphur Fuel Oil (ULSFO) produces significantly less acid, necessitating the use of lower BN oils (typically 15-40 BN).

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