Tiffin Motorhomes ALLEGRO BREEZE, Owner'S Manual

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C U M M I N S E N G I N E S
4-6
Passive regeneration typically occurs when the vehicle is driven at normal highway speeds and/or under
heavy loads.
Active Regeneration
Active regeneration occurs when the exhaust temperatures are not naturally high enough to oxidize the
soot in the DPF faster than it’s collected.
Active regeneration requires assistance from the engine in to increase the exhaust temperature. This is
typically accomplished by the engine injecting a small amount of diesel fuel into the exhaust stream,
which is then oxidized by the DOC, and creates the heat needed to regenerate the DPF.
Active regeneration will occur more frequently in vehicles operated at low speed, low load, or stop and go
duty cycles. Active regeneration only occurs if the engine ECM has detected that the DPF restriction has
reached a specified limit, and may only occur if the vehicle is moving above a preset speed threshold. The
engine ECM will activate and de-activate active regeneration as needed.
Active regeneration is largely transparent to the vehicle operator, the vehicle operator may notice an
increase in turbocharger noise during an active regeneration event, and may notice that the high exhaust
temperature lamp is illuminated, if the vehicle is so equipped.
During active regeneration, the exhaust temperature can be hotter than when the engine is operating at
full load. The exhaust temperature during a normal active regeneration event could reach 1100°F, and
possibly 1500°F under certain conditions.
Warning
Active regeneration can occur any time the vehicle is moving, and the exhaust temperature can remain
hot after the vehicle has stopped moving. The exhaust temperature could reach 1500°F, which is hot
enough to ignite or melt common materials, or to burn people. If the HEST lamp is illuminated do not
operate or park the vehicle with the exhaust near people, or flammable materials.
Aftertreatment Warm-up
The ATS warm up function is used to help prevent the buildup of water condensation in the ATS during
extended idle operation.