Item labeled 'R' as shown in section 6 of the illustration is identified as the __________. Illustration MO-0025

Correct Answer: Option D — aftercooler

Item 'R' is the aftercooler, a heat exchanger located downstream of the turbocharger compressor. Its function is to remove the heat of compression from the intake air. By cooling the air, its density increases, allowing for a greater mass of oxygen to enter the cylinder, which improves combustion efficiency and power output.