Question 26 DDE04 - Designated Duty Engineer - 1000-4000 HP

The Correct Answer is B **Explanation for Option B (Charge air cooler):** The component labeled "3" is situated directly after the turbocharger compressor (which would be labeled "2" if the turbocharger itself is labeled "1") and before the engine intake manifold (charge air manifold, labeled "4"). Its primary function in this position is to cool the compressed air coming from the turbocharger before it enters the engine cylinders. Compressing air heats it significantly; cooling this air increases its density, allowing more oxygen into the cylinder, which leads to greater engine power and efficiency while reducing the thermal stress on the engine components. This device is universally known as a charge air cooler (also often called an intercooler or aftercooler). **Explanation for Incorrect Options:** * **A) Wet muffler:** A muffler is part of the exhaust system, designed to reduce noise. A wet muffler uses water injection for cooling and noise suppression, but it would be located at the end of the exhaust line (past component 5, the turbocharger turbine housing), not in the air intake path. * **C) Charge air manifold:** The charge air manifold (or intake manifold) is the chamber or set of runners that distributes the cooled, compressed air from component 3 into the individual engine cylinder intake ports. Component 3 is positioned *before* the manifold (which is typically labeled 4 in standard diagrams). * **D) Exhaust manifold:** The exhaust manifold is located on the exhaust side of the engine, collecting hot exhaust gases from the cylinders and directing them into the turbocharger turbine. It is entirely separate from the intake air path where component 3 is located.