T-378
3–6
3.6.3
Filter Outlet Temperature Sensor (ESFOT)
The Exhaust Outlet Temperature Sensor (ESFOT),
, monitors exhaust temperature leaving the DPF. It
is located after the DPF and before the tail pipe. This temperature data is utilized to verify that the regeneration
process is being properly controlled.
Figure 3.11 ESFOT
3.6.4
Back Pressure Sensor (ESFP)
The Back Pressure Sensor (ESFP) measures back pressure at the upstream piping. It is located inside the ECM
module. As the DPF gets filled with soot, back pressure will increase. The ESFP verifies that the regeneration
process is being controlled properly.
Figure 3.12 Back Pressure Sensor (ESFP)
3.7 Regeneration
To treat the diesel soot that gets captured in the DPF, a process called regeneration is utilized. During
regeneration, the temperature in the DPF is increased to a level that oxidizes the captured soot, leaving only (fine)
inorganic ash and significantly reducing back pressure. Regeneration is aided by the Diesel Oxidation Catalyst
(DOC) which raises the temperature of the exhaust entering the DPF. Higher exhaust temperatures improve the
regeneration process in the DPF. The target exhaust temperature for regeneration is 1112°F (600°C).
A regeneration generally takes 15 to 20 minutes and may occur 1 to 3 times per day depending on conditions.
The EES will initiate a regeneration cycle when the following conditions are met:
• Back pressure in the exhaust reaches 24 in/H2O (6kPa) in low speed and 36 in/H2O (9kPa) in high speed.
• Automatic regeneration initiated every 12 hours of run time, or for 6 hours of run time if temperatures are
below 32°F (0°C) at the Emissions Control Module (ECM).
