The power output of an automobile engine is directly proportional to the mass of air that can be forced into the volume of the engine's cylinders to react chemically with gasoline. Many cars have a turbocharger which compresses the air before it enters the engine, giving a greater mass of air per volume. This rapid, essentially adiabatic compression also heats the air. To compress it further, the air then passes through an intercooler in which the air exchanges heat with its surroundings at essentially constant pressure. The air is then drawn into the cylinders. In a typical installation, air is taken into the turbocharger at atmospheric pressure (1.01×105Pa), density ρ=1.23kg/m3, and temperature 15.0∘C. It is compressed adiabatically to 1.45×105Pa. In the intercooler, the air is cooled to the original temperature of 15.0∘C at a constant pressure of 1.45×105Pa