Practice question

What is the difference between 'Passive Regeneration' and 'Active Regeneration' of a Diesel Particulate Filter (DPF) in a Euro VI truck?

Passive regeneration occurs automatically during normal highway driving when exhaust temperatures ($250^°–400^°C$) burn soot with $NO_2$; Active regeneration is initiated by the engine ECU injecting post-injection fuel into the exhaust to raise temperatures ($>600^°C$) when the filter is loaded and exhaust temperatures were too low
Passive regeneration requires replacing the filter every morning; active regeneration requires washing it with water
Passive regeneration uses AdBlue; active regeneration uses windshield washer fluid
Active regeneration only works when the engine is switched off overnight

Answer: A — Passive regeneration occurs automatically during normal highway driving when exhaust temperatures ($250^°–400^°C$) burn soot with $NO_2$; Active regeneration is initiated by the engine ECU injecting post-injection fuel into the exhaust to raise temperatures ($>600^°C$) when the filter is loaded and exhaust temperatures were too low

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