Which statement about an intercooler is correct?

• A. A device used to cool the engine oil.
• B. A device used to reduce the temperatures of the compressed air before it enters the fuel metering device.
• C. A component of the propulsion system.
• D. A weather instrument.

Answer: (B)

An intercooler cools the air after it has been compressed by a turbocharger or supercharger. Compressing air raises its temperature and lowers its density, which makes a turbocharged engine less efficient and more prone to knock. By cooling the charge air, the intercooler increases its density, so more oxygen can enter the engine per unit volume. This improves combustion quality and helps the fuel metering system measure and deliver the right amount of fuel. In high-boost conditions, cooler air also helps prevent pre-ignition and detonation. So the correct statement is that it reduces the temperatures of the compressed air before it enters the fuel metering device. The other options describe cooling engine oil, being part of the propulsion system, or a weather instrument, which aren’t what an intercooler does.