HARRIER BS VI - SERVICE MANUAL

KRYOTEC ENGINE

118

Diesel engines produce a variety of particles during

combustion of the fuel/air mix due to incomplete

combustion. Diesel particulate matter resulting

from the incomplete combustion of diesel fuel

produces soot (black carbon) particles. Soot and

other particles from diesel engines worsen the

particulate matter pollution in the air and are

harmful to health.

Diesel particulate filters (DPF) are devices that

physically capture diesel particulates to prevent

their release to the atmosphere. The exhaust gases

pass through the filter, which collects particles from

the gases. Collected particulates are removed from

the filter through thermal regeneration.

SELECTIVE CATALYST REDUCTION (SCR)

Selective Catalytic Reduction (SCR) is an

advanced active emissions control technology

system that injects a liquid reductant agent through

a special catalyst into the exhaust stream of a

diesel engine. The reductant source is Diesel

Exhaust Fluid (DEF). This reductant is also known

as Diesel Exhaust Fluid (kDEF). Diesel Exhaust

Fluid (DEF) sets a chain of chemical reaction that

converts nitrogen oxides into nitrogen, water and

tiny amounts of carbon dioxide.

Mixer is used to thoroughly mix ammonia in the with

the exhaust gas.

DIESEL EXHAUST FLUID (DEF) INJECTOR

Dosing of precise amount of DEF (Diesel Exhaust

Fluid (DEF)) is necessary for the required chemical

reactions to begin in the SCR system.

Diesel Exhaust Fluid (DEF) injector injects the

precise amount of Diesel Exhaust Fluid (DEF) into

the SCR on exhaust stream.

Diesel Exhaust Fluid (DEF) contains two amino

groups and when disintegrating in heat, they turn

into ammonia, carbon dioxide and water. Within the

SCR catalyst the NOx is catalytically reduced by

the ammonia into water and nitrogen, which are

both harmless.

DPF related warning lamps

The vehicle is equipped with a Diesel Particulate

Filter (commonly known as DPF). DPF is a

mechanical filter that physically traps particulate

matter from diesel engine 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 channels 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.

DPF equipped in Harrier vehicle normally

regenerates automatically which is controlled by

engine management system.

In certain specific driving conditions, DPF

regeneration may not happen automatically as the

desired temperatures required to regenerate soot

many not be achievable due to specific driving

conditions. This includes prolonged driving at low

vehicle speeds for considerable amount of time

(driving in heavy city traffic), prolonged running of

the engine in idle conditions etc. In such cases, a

warning lamp as indicated below will be illuminated

in the instrument cluster indicating that soot

regeneration is insufficient.

This warning lamp switches ON constantly to

indicate that the DPF needs to be regenerated. This

lamp does not indicate any malfunction.

The warning lamp remains OFF during normal

vehicle behaviour and lights up only when driving

condition requires the driver to be notified. When

this lamp is ON, keep the car running ideally at 3

gear 60kmph with engine speed over 2000 rpm

until regeneration is completed and warning lamp

goes OFF. The process normally takes about 20

minutes.

Note: Do not shut down engine till the warning lamp