How do aftercoolers improve diesel engine performance?

Aftercoolers, also known as intercoolers, improve diesel engine performance by reducing the temperature of the charge air.1

When air is compressed—such as by a turbocharger—its temperature rises, which decreases its density and limits the total mass of air that can be introduced into the cylinder. By cooling this compressed air before it enters the combustion chamber, an aftercooler increases the air's density, allowing a greater mass of air to be packed into the engine.1

This process enhances the engine's overall performance in terms of both power output and fuel economy. These coolers are available in both air-to-air and air-to-coolant configurations.12