Diesel Oxidation Catalytic Converter, Component Description - Mercedes-Benz OM 471 Introduction Into Service Manual

System components
GF49.10>W>3006H
ENGINES 471.9 in MODEL 963, 964 with CODE (M5Z) Engine version Euro VI
Location
4 Diesel oxidation catalytic converter
(DOC)
5 Diesel particulate filter (DPF)
A70 Exhaust aftertreatment unit inlet
NOx sensor control unit
A70 b1 Exhaust aftertreatment unit inlet
NOx sensor
B37 Exhaust pressure sensor upstream
of diesel oxidation catalytic
converter
B38 Exhaust pressure sensor
downstream of diesel particulate
filter
B67 Exhaust temperature sensor
upstream of diesel oxidation
catalytic converter
B68 Exhaust temperature sensor
downstream of upper diesel
oxidation catalytic converter
The diesel oxidation catalytic converter (DOC) (4) is integrated in
the exhaust aftertreatment unit. It is the first location upstream of
the diesel particulate filter (DPF) (5) to be reached by the exhaust
downstream of the engine.
Task
The diesel oxidation catalytic converter (DOC) (4) is used to
convert the carbon monoxide (CO) and hydrocarbon (HC) in the
exhaust into less harmful carbon dioxide (CO
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Function
The exhaust coming from the engine flows through the diesel
oxidation catalytic converter (DOC) (4). Part of the nitrous oxides
(NOx) that is present is reduced by the chemical reaction with the
rare metals in the coating, meaning that oxygen is released. The
released oxygen then allows the CH and CO parts of the exhaust
to oxidize, resulting in CO and water.
2
208

Diesel oxidation catalytic converter, component description

B69 Exhaust temperature sensor
downstream of lower diesel
oxidation catalytic converter
) and water (H O).
2 2
– This printout will not be recorded by the update service. Status: 09 / 2011 –
B70
Design
The diesel oxidation catalytic converter (DOC) (4) consists of two
cylindrical inserts with a metal sleeve. Inside this is the actual
catalytic converter element, which consists of a porous monolithic
block made from a special ceramic material.
In order to make it possible for the required chemical reactions to
take place and assist with passive regeneration of the diesel
particulate filter (DPF) (5), the catalytic converter element is
covered with a series of rare metals > the so>called oxidization
layer (wash coat).
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Since a significant amount of pollutant conversion only occurs
from a temperature of about 250 ∞C, the exhaust aftertreatment
unit with the diesel oxidation catalytic converter (DOC) (4) is
located as close to the engine as possible on the right>hand side of
the vehicle.
20.7.11
W14.40>1576>76
Exhaust temperature sensor
downstream of diesel particulate
filter