TATA Motors HARRIER, Owner'S Manual

Page: 234 / 267

MAINTENANCE
224
In order to reduce the NOx levels even
further, SCR system is used. In SCR sys-
tem, DEF is injected in the exhaust
stream. With the help of injected ammo-
nia in the DEF, NOx is converted into
harmless constituents.
NOTE
In order to control exhaust emis-
sions, this vehicle is equipped with
SCR system through which DEF
(Diesel Exhaust Fluid) continuously
flows. It is normal to have a noise
from the SCR system during vehi-
cle operation or for about
20
to
30
seconds after engine is switched
off.
Regeneration Process
DPF is a mechanical filter that physically
traps particulate matter from diesel en-
gine exhaust gas.
DPF traps the particulate matter in the
following way:

Filtration – Particulates / soot are
collected in the inlet channel of the
filter.

Regeneration – When the filter chan-
nels are filled up with soot, they are
cleaned automatically by the engine
management system. This process is
known as DPF Regeneration and this
will happen during normal running of
the vehicle.
In certain specific driving conditions,
DPF regeneration may not happen auto-
matically as the desired temperatures
required to regenerate soot many not be
achievable due to specific driving condi-
tions. This may happen in prolonged
driving at low vehicle speeds for consid-
erable amount of time (driving in heavy
city traffic), prolonged running of the en-
gine in idle conditions, use of adulter-
ated diesel etc.
In such cases, a DPF warning lamp will
be illuminated indicating that soot re-
generation is insufficient
DPF Lamp
The lamp blinks constantly
to indicate that the DPF
needs to eliminate the
trapped pollutants (particulate matter)
through the regeneration process, it
therefore does not indicate a malfunc-
tion. The lamp remains off during the en-
tire DPF regeneration and it lamps up
only when driving conditions require the
driver to be notified. To switch off the
lamp, keep the car running until regen-
eration is complete (ideally at
3
rd
gear,
60
kmph. with engine speed over
2000
rpm). The process normally takes about
20
minutes.