The document discusses regeneration of diesel particulate filters (DPFs) in fire apparatus engines. DPFs capture particulate matter from exhaust but require periodic regeneration to clear the accumulated soot. Regeneration increases exhaust temperature to burn off soot through either passive regeneration during normal operation or active regeneration initiated by the driver. Active regeneration involves parking the vehicle and triggering an automated high-idle process that takes 20-45 minutes to complete regeneration. Warnings notify the driver when regeneration is recommended or required to avoid engine damage.

1. Apparatus Regin
Oak Island Fire Department

2. What Is Regeneration?

3. What Is Regeneration?

4. What Is Regeneration?
During the past two decades, the EPA has worked with diesel
engine manufacturers to reduce emissions, specifically focusing
on NOx and particulate matter (PM)-unburned hydrocarbons
from the fuel that pass through the engine into the exhaust
stream

5. What Is Regeneration?
The standards implemented in 2007 (EPA07) included a 90
percent reduction in allowed PM. To achieve that level, heavy-
duty engine manufacturers included a diesel particulate filter
(DPF) as part of the certified engine installation starting in 2007

6. What Is Regeneration?
The DPF is a canister that replaces the typical muffler. In
addition to providing the necessary reduction in exhaust noise,
there is also a ceramic matrix in the canister that captures
particulate matter in addition to a catalyst to aid in the
regeneration process

7. What Is Regeneration?
Over time, as the PM accumulates in the filter, the backpressure
increases. Eventually, it becomes necessary to clear out the
accumulated PM to maintain an acceptable level of
backpressure

8. What Is Regeneration?
Regeneration is the process of clearing out the PM from the
filter

9. What Is Regeneration?
There are subtle differences from one manufacturer to another,
but the basic process is to increase the exhaust temperature
enough to burn off the accumulated PM

10. The majority of fire apparatus built with EPA07 certified heavy-
duty engines were equipped with a DPF. All fire apparatus built
with EPA10 or later certified engines are equipped with a DPF.
Any apparatus with a DPF will require regeneration.

11. Regeneration Types
There are two main classifications for regeneration: passive and
active

12. Passive Regeneration
When a diesel engine operates at significant load and speed,
there is a considerable amount of heat energy passed through
to the exhaust system. If the temperature of the exhaust is high
enough, some of the PM present in the DPF will burn off on its
own. This is passive regeneration.

13. Fire Apparatus
The duty cycle of most fire apparatus does not provide optimum
conditions for passive regeneration, so eventually an active
regeneration will be necessary.

14. Active Regeneration
There are two types of active regeneration: automatic and
stationary. Stationary regeneration is also referred to as parked
regeneration, high idle regeneration, or nonemission
regeneration

15. Active Regeneration
When an active regeneration is required, the engine controls
will look for operating conditions where this can be performed
in the background-for example while driving down the road or
while in pump mode at a fire scene

16. Active Regeneration
Regeneration during pump mode is standard on some engines
and optional on others. During these conditions (with minimum
engine speed, load, and so on), the engine controls will actively
initiate regeneration by dosing fuel into the exhaust stream,
which then reacts with the catalyst in the aftertreatment device,
thereby raising the exhaust temperature and burning off the PM

17. Active Regeneration
This type of regeneration, which requires no driver intervention,
is an automatic regeneration.

18. Active Regeneration
If the engine does not see the necessary conditions for
automatic regeneration, the driver is given warning lights (first
the DPF lamp, then the check-engine lamp, and finally the stop-
engine lamp) to indicate that the DPF is being loaded and needs
to be cleared

19. Active Regeneration
To initiate a stationary regeneration, the vehicle should be
parked outside in a clear area so the exhaust temps do not
create secondary problems

20. Active Regeneration
The operator then sets the park brake and triggers the
regeneration by activating the DPF regen switch

21. Active Regeneration
At this point, the engine speed will increase; fuel will be dosed
into the exhaust stream; and, during the next 20 to 45 minutes,
the DPF will be cleared of the stored PM.

22. Regeneration Instructional Video
• https://www.youtube.com/watch?v=BnUXJuHbypc&feature=e
m-share_video_user

23. When to Regen
The first indication a driver will receive is a solid amber DPF
lamp and the digital display will show DPF REGEN
RECCOMENDED. If the apparatus is not regenerated at his
warning, the next message displayed will say DPF REGEN
REQUIRED. If the apparatus is still being operated without being
regenerated, the final message will require the apparatus be
shut down immediately and the unit must be taken out of
service.
Regeneration can not be performed unless the system
recommends regeneration, therefor regeneration can not be
performed on any routine schedule.