Practice question

The regeneration type that allows cleaning of the DPF in stationary truck operations and requires operator involvement to initiate is Parked Regeneration.

  1. Passive Regeneration
  2. Active Regeneration
  3. Automatic Regeneration
  4. Parked Regeneration

Answer: D — Parked Regeneration

The event being described is a parked regeneration. In this mode, cleaning the Diesel Particulate Filter is planned and conducted while the truck is stationary, giving the operator control over when to start the cycle. This allows the exhaust to be heated to a high, sustained temperature safely and without the variables of driving, which helps burn off more soot effectively. The operator initiates this process—typically by selecting parked regen on the vehicle’s system—so it’s specifically designed for use during stationary operations, such as in a depot or shop setting. By contrast, passive regeneration happens automatically during normal driving when exhaust temperatures are high enough to burn off soot, with no operator input. Active (or automatic) regeneration typically occurs during operation as well, driven by the engine control system to raise the exhaust temperature, often without requiring the vehicle to be parked. Parked regeneration is the option that uniquely relies on the vehicle being stationary and on the operator initiating the process.

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