SSANGYONG Y200 Manual page 2077

DI04-38
DOC (Diesel Oxidation Catalyst)
System and principle
Oxidation catalytic technology for diesel engine is basi-
cally the same with it of gasoline engine used before de-
velopment of 3 primary catalyst (2 primary catalyst), and
its effect and performance were already proved.
DOC (Diesel Oxidation Catalyst) reduces HO and CO con-
tained exhaust gas over 80 %, and removes SOF (Soluble
Organic Fraction) over 50 ~ 80 %, but because its portion
in total PM is low, it reduces approx, 20 ~ 40 % of TPM
(Total Particulate Material).
Because of low reducing rate for PM of DOC, in order to
guarantee safety rate of PM regulation, this technology is
being used mainly. And it should keep over 80% of PM
reducing rate, and at present it plays a role as a transition
stage.
And also it reduces diesel odor and black smoke, plati-
num or palladium are being used as a catalyst.
On the other hand, it is a problem that it makes the reac-
tion of oxidation, which SO
reacting to oxygen in exhaust gas, if temperature of ex-
haust gas becomes over 300°C, and this produced gas is
very harmful to human body. To prevent is, previously it is
requested that the sulfur content rate of fuel should be
below 0.05 %, and in the future it is being expected to
keep it below 0.01 %.
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
produce SO and H SO
2 3 2
Catalytic converter structure
The Catalytic converter of monolith type consists of 2 walled
metal bodies which is made of Cordierite.
The principal element of converter consists of the materi-
als like Alumina or oxidized Serume in order to apply to
Ceramic Monolith. Washer coat operates first, and cata-
lytic metal elements (Pt, Pd, Ph) operates to washer coat
next.
Monolith type is lighter than other types, easy to manu-
facture and quickly approaches to proper temperature.
Washer coat is used to make a contact surface with ex-
haust gas bigger by adhering closely to small holes of
inner layer.
If a lead compound or phosphorus adheres to the surface
and the temperature rises, its surface is decreased.
The total area of general monolith converter is about
45,000 ~ 500,000 ft
Generally Alumina (AL
by
4
its 7 phases of gamma, delta, theta have big areas and
high stability for the temperature, and nowadays gamma
Alumina is used usually.
Mat
Lower part of
converter
Inlet gas
3
. (10 times of a football field)
O 3 ) is used as a raw material and
2
Cover
Upper part of
Insulation
converter
Plate
Monolith catalyst
Outlet gas
EXHAUST SYSTEM
DI ENG SM - 2004.4
Y220_04040