Which device drops the temperature of the compressed air and increases its density before it enters the cylinder using air as the cooling agent?

• A. Air Cleaner
• B. Air Silencer
• C. Aftercooler
• D. Intercooler

Answer: (D)

When air is compressed, it heats up. Cooling that air before it enters the engine increases its density, allowing more air mass to be drawn in each intake cycle. An intercooler does exactly this between stages of compression by using ambient air to remove the heat from the already compressed air. That drop in temperature raises density, which improves engine charging and efficiency, and it does so using air as the cooling medium.

Air cleaners and air silencers don’t affect air temperature or density; they handle contaminants and noise. An aftercooler also cools the air, but it does so after the final compression stage, not between stages. The device positioned between compression stages is the intercooler, making it the best choice for increasing air density before entry into the cylinder.