🔍 Key Concepts

• Location and function of the component labeled W in relation to the turbocharger/air box • How a charge air (scavenge air) cooler on large marine diesels is usually cooled • Difference between the cooling medium and the fluid being cooled in a heat exchanger

💭 Think About

• Look closely at where air is flowing from the turbocharger toward the cylinders—what role would the unit at W play in that path? • If the part at W is an air cooler, ask yourself: which fluid is passing through the tubes to remove heat, and which fluid is having its temperature reduced? • Among the options, which one is most commonly used as the cooling medium for an air cooler mounted externally on the side of a large slow‑speed diesel engine?

✅ Before You Answer

• Verify whether W appears to be a heat exchanger (tube bundle, end covers) rather than a solid casting or tank. • Decide which fluid actually circulates inside that exchanger as the coolant, not the one being cooled. • Eliminate any choices that represent a lubricant function rather than a dedicated cooling medium for intake/scavenge air.