In which lubrication application is a...

🔍 Key Concepts

• Alkaline reserve (TBN – Total Base Number) and its role in neutralizing acids formed during fuel combustion • Differences in how trunk-type vs. crosshead diesel engines handle cylinder lubrication and crankcase oil • Which systems are exposed to acidic combustion products versus relatively clean working conditions

💭 Think About

• Which of these lubrication systems is most directly exposed to the byproducts of fuel combustion, especially sulfuric and other acids? • Why would an oil that can neutralize acids (has an alkaline reserve) be more important for some diesel engine designs than for turbines or bearings isolated from combustion gases? • In which engine type does the same oil both lubricate and help deal with contaminants from the combustion space?

✅ Before You Answer

• Identify which option involves oil that shares space with the combustion chamber or piston undercrown, not just clean bearings or gears • Confirm which engine design uses separate cylinder oil and crankcase oil, versus a common oil system • Eliminate any applications where the oil is not routinely contaminated by combustion acids (e.g., closed, clean systems)

In which lubrication application is a lubricating oil with an alkaline reserve most likely to be used?

Trunk type diesel engine lubricating oil.

Stern tube bearing lubricating oil.

Steam turbine lubricating oil.

Crosshead diesel engine bearing lubricating oil.

🔍 Key Concepts

💭 Think About

✅ Before You Answer