Only on boosted engines. This schematic includes one; a naturally aspirated engine does not.
Teaching inline-four schematic. Not a specific car. Turbo
Exhaust gas spins a turbine that packs intake air.
On the exhaust manifold outlet.
Black diesel smoke (FR article)
Do not imply every inline-four has a turbo. The black-smoke diesel article is combustion, not “what is a turbo”.