TELKOM
NIKA
, Vol.11, No
.3, Septembe
r 2013, pp. 4
81~488
ISSN: 1693-6
930,
accredited
A
by DIKTI, De
cree No: 58/DIK
T
I/Kep/2013
DOI
:
10.12928/TELKOMNIKA.v11i3.991
481
Re
cei
v
ed Fe
brua
ry 25, 20
13; Re
vised
June 16, 20
13;
Accept
ed Ju
ne 29, 201
3
Reduce NOx Emission
s by Adsorber-Reduction
Catalyst
on Lean Burn Engine
Dongp
eng Y
u
e
1
, Qing Ch
ang
2*
, Lei Li
u
2
, Wen Zha
ng
2,3
, Shaoshu Chen
2
, Zh
ijun Li
2
1
School of Aut
o
motive a
nd T
r
ansp
o
rtatio
n,T
i
anji
n
Un
iv
ersit
y
of
T
e
chnolo
g
y
and Educ
atio
n
,
T
i
anjin 3
0
0
2
2
2
2
State Ke
y
La
b
o
rator
y
of Engi
nes,T
ianjin U
n
i
v
ersit
y
,T
ianji
n
300
07
2
3
T
i
anjin
electro
n
ic inform
ation
vocatio
nal tec
h
nol
og
y col
l
e
ge,
T
i
anjin 30
03
50
*Corres
p
o
ndi
n
g
author, e-ma
i
l
: matrixfutur
e
@sina.c
o
m,
T
e
lp: +
86 022
27
406
78
1, F
a
x: +
86 02
2 27
38
33
62
A
b
st
r
a
k
Peng
aru
h
siste
m
kata
lis b
a
ru
yang ter
d
iri
dar
i tiga car
a
trad
i
s
ion
a
l ko
nverte
r katalis d
an
a
d
sorb
er-
reduks
i
ko
nver
ter katal
i
sis
pa
da k
a
rakteristik
e
m
isi
d
a
n
BS
F
C
(Break
e S
p
ecific F
u
el
Co
n
s
umptio
n-BSF
C)
dari s
e
b
uah
mesin
be
nsin
ya
ng ra
mpi
ng
un
tuk me
mbak
ar
diteliti
d
a
la
m
mak
a
l
ah
in, d
i
ma
na sk
e
m
a y
a
n
g
berb
eda
dar
i k
a
talis
pen
gatur
an se
bu
ah ko
n
v
erter da
n kec
epata
n
ya
ng b
e
rbe
da-b
e
d
a
d
an j
uga
be
ba
n
n
ya.
Hasil
menu
nj
u
kkan ba
hw
a p
o
sisi terb
aik d
eng
an tig
a
car
a
Catalyst a
d
a
l
ah se
be
lu
m N
O
x diserap
ol
eh
Catalyst de
ng
an seb
u
a
h
skema untuk
me
ngatur ko
nver
t
e
r ternyata ad
ala
h
cara terb
aik. Den
gan c
a
r
a
me
ng
efisie
nsik
an konv
erter d
an
men
gur
ang
i emisi NO
x da
l
a
m
m
e
si
n
ben
si
n
te
rseb
u
t. D
i
m
a
na
te
rd
apa
t
efek d
a
ri k
e
ce
patan
p
ada
e
m
isi g
a
s
bua
ng
dan
BSF
C
j
u
g
a
terka
i
t de
ng
a
n
rasi
o
pew
aktuan
da
la
m
pro
s
es
me
mbak
ar d
a
n
nil
a
i
abs
olut
d
a
ri ke
du
a w
a
ktu dar
i ko
nv
erte
r katalis
terseb
ut. Beba
n
mes
i
n a
d
a
l
ah
fakto
r
utama ya
ng b
e
r
pen
garu
h
terh
ada
p karakter
i
s
tik emis
i g
a
s
bua
ng d
an BS
F
C
dari
mes
i
n
tersebut. Di
da
pati
semaki
n ba
ny
ak e
m
isi NOx
,
maka n
ila
i NOx berku
ra
n
g
untuk tin
g
k
a
t konversi (
CNOx) dan a
k
an
me
nd
apatk
an
nila
i BSF
C yan
g
leb
i
h b
a
ik.
Ka
ta
k
unc
i:
membak
ar le
m
a
k, m
e
sin
bens
i
n
, katalis ads
or
ber-re
duksi, N
O
x, em
isi
A
b
st
r
a
ct
The effect of a new catalyst
system
composed
of tr
aditional three way catalyst conv
erter an
d
adsor
ber-reduc
tion catalys
i
s c
onverter on the em
ission
characteristics and BSFC
(Breake Specific Fuel
Cons
u
m
ptio
n-
BSF
C)of a l
e
a
n
b
u
rn
gas
oli
ne
eng
in
e
ope
ra
te
d we
re
in
ve
sti
g
a
t
e
d
i
n
th
i
s
pa
pe
r un
der
different sch
e
m
es
of catalyst converter arra
nge
ment
an
d d
i
fferent spe
eds
and lo
ads. T
h
e results show
that
the positi
on of
T
h
ree W
a
y Ca
talyst
is before
the NOx adso
r
ber Cata
lyst
was the best schem
e of catalyst
converter arr
a
n
g
e
m
e
n
t. W
h
ich has the hig
h
e
s
t converte
r efficiency of red
u
c
tion NOx emi
ssion in l
e
a
n
burn
gaso
lin
e
eng
in
e. T
he
effects
of spe
e
d
on
th
e ex
ha
ust e
m
is
sion
an
d BSF
C
w
e
re a
l
so
rel
a
ted to t
he r
a
tio
of
lea
n
bur
n ti
me
to rich bur
n ti
me
an
d the a
b
sol
u
te
val
ue
of both ti
me
of the ads
orber-
r
educti
on cata
l
yst
converter. T
h
e
load of the en
gin
e
w
a
s the ma
in infl
ue
ntial
factor to
the
exha
ust emissi
on char
acterist
ics
and BSF
C of le
an bur
n gas
oli
ne en
gi
ne, an
d
the mor
e
lo
ad
of the eng
ine w
a
s, the mor
e
N
O
x emissi
on, the
less NOx conv
ersion rate (C
NO
x
) and the bett
e
r BSF
C w
e
re.
Ke
y
w
ords
: lean burn, gas
oline eng
ine, adsorber-reduction catalyst, NOx,
emission
1. Introduc
tion
As the emi
s
sion
reg
u
lati
on be
com
e
s more a
nd
more
stri
ct, it’s too ha
rd
to redu
ce
exhau
st emissi
on
s only
depen
ding
on improvi
ng intern
al operation p
r
oce
s
s of en
gine.
Con
s
e
quently
, many cou
n
tries h
a
ve develop
ed
the exhau
st after-tre
atment
technol
ogy to
redu
ce exh
a
u
s
t emission
s,
mean
while, retain other p
e
r
forma
n
ce of the engin
e
[1].
Traditio
nal t
h
ree
-
way-cat
a
lyst (T
WC
) synchronou
sly re
du
ce
s CO,
HC
and
NOx
effectively only when the
g
a
soli
ne en
gin
e
is working
unde
r stoi
chi
o
metri
c
air/fu
el ratio
condit
i
on
[2]. Excess a
i
r ratio of lea
n
burn is mo
re t
han o
ne,
so NOx emission
can
not be re
du
ced b
y
three
-
way-catalyst. Curren
tly,
the main technol
ogie
s
of reduci
ng
NOx emissio
n
of lean bu
rn
gasoline
en
gi
ne a
r
e
EGR[
3-7]
and
catal
y
ze[8-1
3]. Bu
t the hig
h
EG
R
rate
de
cre
a
se
s the
velo
ci
ty
of flame diffusion, an
d co
nse
que
ntly worsen
s the BSFC. Althoug
h the Ricard
o develop
ed
an
variable
tum
b
le CCVS sy
stem
[3] and
goo
d
exh
a
u
s
t
st
ratified combu
s
tion was obtain
ed with
high EGR
rat
e
of 70%, The stru
cture of this
system
wa
s com
p
lica
t
ed and NOx emissi
on wa
s
also
hard to
satisfie
d the
requ
est
of stri
cter
e
m
ission
reg
u
lati
on. For th
e
method
s of
NOx
decompo
sin
g
[14] and selective ca
taly
st redu
ction
(SCR) [15]
using for vehi
cle exhau
st, the
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 48
1 – 488
482
NOx cataly
st conve
r
si
on ra
te and the th
ermal
stabilit
y
of the catalyst are all ha
rd to satisfie
d the
pra
c
tical
re
qu
est. Co
mpa
r
e
d
with the
s
e
method
s of
redu
cing l
ean
burn
NOx, Th
e NOx
ad
sorber
redu
ction
ca
talyst combi
ned with T
W
C
can pu
rify the NOx high efficiently within wide
temperature
scope.
With this meth
od, the BSFC
of l
ean bu
rn
gasoline en
gine
is dete
r
iorate
d
little, while the catalyst co
nversi
on rate
of NO
x CNO
x can be 97
% during the
sho
r
t time of
fuel
rich
conditio
n
. The Auth
ors u
s
ing
a
modified
16
valves EFI
Qua
s
i-Hom
o
geno
us l
ean
burn
gasoline e
ngi
ne studi
ed th
e effect of different
sc
heme
s
of arrang
e
m
ent NOx ad
sorbe
r
co
nve
r
ter
and T
W
C, dif
f
erent lo
ad
s
and
sp
eed
s
on exh
aust
e
m
issi
on ch
aracteri
stics an
d
BSFC with
the
combi
nation
of NOx adsorber catalyst a
nd TWC.
2. Rese
arch
Metho
d
Experimental
rese
arch on
the effect of
different co
mbination
scheme
s
of lean burn
adsorb
e
r
cat
a
lyst and T
W
C, load
s and
spee
ds
o
n
e
x
haust emi
s
sion ch
ara
c
te
ri
stics and BS
FC
were
con
d
u
c
ted o
n
a
mo
d
i
fied 16
valves EFI
Qu
asi
-
Ho
mog
enou
s le
an
bu
rn
gasoline
en
gin
e
with the le
a
n
bu
rn g
a
so
line en
gine
electroni
c co
ntrol system
devel
op
ed by
the
auth
o
rs
colle
ague
s [8
]. Figure 1
sh
ows the sch
e
m
atic of ex
ha
ust pipeli
ne d
e
sig
n
of the l
ean bu
rn
NO
x
adsorb
e
r catalyst expe
rim
ent sy
stem.
Ci, Ti
re
p
r
ese
n
t
th
e co
nce
n
t
r
a
tio
n
an
d te
mp
er
a
t
ur
e o
f
exhau
st emi
s
sion
at the i
place respe
c
tively. T
he pa
rts 2 a
nd 3
in
the pipeli
ne
can be
chang
ed
each other.
There are th
ree schem
e o
f
the parts
arrang
eme
n
t in the exhaust
pipeline. In the
scheme
1, the part
s
se
que
nce i
s
1-5-2
-
4 with NO
x adso
r
be
r but without TWC. In the schem
e
2,
the parts
seq
uen
ce is 1
-
5-2-3
-
4, that is, the
NOx adsorbe
r is set before T
W
C.
On the cont
rary,
in the schem
e 3, the NOx adsorb
e
r lo
ca
tes afte
r the
TWC with the
sequ
en
ce of 1-5
-
3-2-4.
The ori
g
inal
engin
e
se
nsor an
d wires were pre
s
e
r
ved, and th
e origin
al ECU
wa
s
repla
c
e
d
by t
he lea
n
b
u
rn
gasoline
engi
ne
contro
l E
CU
whi
c
h
ca
n re
gulate th
e A/F ratio
e
a
sily.
The ele
c
tro
n
i
c
co
ntrol thro
ttle and linea
r A/F sensor
were also used for the sp
ecial de
man
d
o
f
the lean bu
rn
NOx adsorb
e
r-red
u
ctio
n catalyst
and le
an burn ga
sol
i
ne engin
e
op
eration. Set the
value of
A/F
and
ope
rating
time in
adva
n
ce
a
c
cordin
g to th
e d
e
ma
nd of
expe
rim
ent. Th
rottle
and
the inje
ction
pulse can be
modified by
lean b
u
rn
ga
solin
e engi
ne
ECU to e
n
sure the
re
qui
red
A/F and a
ste
ady output
po
wer.
Line
ar A
/
F sen
s
o
r
kee
p
the e
ngine
workin
g in th
e rig
h
t ra
nge
of
A/F via feedback sig
nal.
1. Engine
2.
lean NOx adsorb
e
r catal
y
st,
3. TWC
4. Muffler,
5. Temper
ature
reg
u
lator
Figure 1. Sch
e
matic of exp
e
rime
ntal system in
lean NOx adso
r
be
r
catalyst in ex
hau
st pipe
3. Results a
nd Discu
ssi
on
3. 1 The Effe
ct of
Differe
n
t Combina
t
i
on Schemes
of NOx
Ads
o
rber-redu
c
tion Cataly
st
and Thre
e
Wa
y
Cataly
st on Exhaus
t Emission Ch
arac
teris
t
ics
The effect
s o
f
catalyst sy
stem arrang
e
m
ent of different schem
e
on NOx emission
and
NOx co
nversi
on rate
C
NOx
were sh
own in Figure 2 an
d Figure 3.
The x-axis de
n
o
tes the ratio
of
the absol
ute lean bu
rn ope
rating time tlean and the a
b
sol
u
te rich condition op
erating time trich.
The y-axi
s
d
enote
s
the
concentratio
n
of NO
x emi
s
sion
(1
) an
d
the NOx
co
n
v
ersio
n
rate
C
NOx
(%
) re
sp
ectiv
e
ly
.
As sh
owed in
Figure 2, all
of the three
d
i
ffe
rent cataly
st arran
geme
n
ts can redu
ce NOx
emission of l
ean bu
rn ga
soline engi
ne.
The NOx e
m
issi
on is a
b
out 800 x 10
-6
before catal
y
st.
After conve
r
sion, the NOx
emissi
on
s re
duc
e sig
n
ificantly no matter the ratio o
f
t
lea
n
to
t
rich
. For
example, wh
en the ratio
o
f
t t
l
ean
to
t
rich
is 200
s:20
s,
NOx emi
ssi
o
n
schem
e 1 a
nd sche
me 2
was
redu
ce
d to
a
bout 3
0
0
x 1
0
-6
,
lowe
r 62.
5%.
NOx em
issi
on of sch
e
me 3 red
u
ced
to
50
x
1
0
-6
,
lowe
r 9
3
%. The
scheme
3 is
better th
an the
sche
me 1 a
nd
2. And a
s
the
absolute time
of
t
lean
/t
rich
decre
ase
d
from
20
0s: 20
s to
40
s: 4s,
NOx e
m
issi
on
after
catalyzed al
so re
du
ced f
r
o
m
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
1693-6
9
30
Red
u
ce NO
x
Em
ission
s by Adsorber-Re
ductio
n
Catal
yst on L
e
an B
u
rn Engi
ne (Don
gpe
ng Yu
e)
483
300 x 1
0
-6
to 50 x 10
-6
fo
r
scheme
1 a
n
d
2, an
d re
du
ced f
r
om
50
x 10
-6
to 15 x
10
-6
for
sc
heme
3. The a
bov
e expe
riment
re
sults ill
um
inate that
ca
talyst arrang
ement a
s
three sch
e
me
can
achi
eve better effect of NOx emissi
on redu
cti
on, further more, as the absolute
time of
t
lean
/t
rich
decrea
s
e
d
, NOx emission redu
ced.
Figure 2. Effects of differe
n
t
sche
m
e
s
on
NOx emissio
n
(n=
1800
r/
min, pe= 0.2
MPa)
These
res
u
lts c
a
n be explain as
: when t
he thre
e
way
s
c
a
talys
t
is
loc
a
ted before the lean
burn
NOx ad
sorbe
r
-red
uct
i
on cataly
st, the exhau
st
emis
s
i
on enters
three way
s
c
a
talys
t
at firs
t,
and rea
c
ts wi
th the redu
cin
g
agent rhodi
um. Although
the oxygen is ri
ch in the
e
x
haust ga
s, th
e
conve
r
si
on
proce
s
s of
NO
x is
re
stri
cted
to
some
ext
ent, and
the
NOx
conve
r
si
on
rate
C
NOx
is
decrea
s
e
d
. But this arra
ng
ement ca
n re
duce the con
c
entration of O
2
, HC, CO and the ab
sol
u
te
value of NOx emission
ent
ering th
e lea
n
burn
NOx a
d
s
orber-reduc
t
ion catalys
t, s
o
as
to reduc
e
the vaca
ncy
of oxygen
adsorb
ed ,all
eviate the lo
ad of lea
n
b
u
rn
NOx ad
sorbe
r
-red
uct
i
on
catalyst, a
n
d
prolo
ng t
he ti
me b
e
fore
the catalys
t
’s
saturation.
While t
lean
/t
ric
h
is
c
o
ns
tant, as the
absolute time
of t
lean
/t
ric
h
diminishi
ng, on
the one ha
n
d
, the absolu
t
e quality of NOx emi
ssi
o
n
is
small, and the time is
short, so the possi
bility of
NOx overflowi
ng is little; on the other hand,
there i
s
a process of
NOx redu
ction i
n
every
short time, whi
c
h make the possibility of
NOx
overflowi
ng
smalle
r. In the p
r
o
c
ess
of NOx
red
u
ction, all th
e NOx a
d
so
rbed
is
alm
o
st
deoxidi
z
ed.
Whe
n
the e
ngine turns t
o
lean bu
rn
con
d
ition ag
ain, the adsorbe
r capa
cit
y
o
f
catalyst i
s
en
han
ced. Th
u
s
, the NOx e
m
issi
on
co
n
s
eque
ntially re
duces. In oth
e
r word
s, a
s
the
absolute time
of t
lea
n
/t
ri
ch
diminishi
ng, the NOx emi
ssi
on of
t
h
e cat
a
ly
st
sy
st
em re
duc
e
s.
Figure 3. Effects of differe
n
t
sche
m
e
s
on
NOx conve
r
sion efficien
cy C
NOx
(n=180
0r/min
,pe=0.2MP
a
)
As sho
w
n in
Figure 3, the NOx co
nversi
on rate C
NOx
of catalyst arrangem
ent of scheme
1 and
2 i
s
al
most e
qual,
but both l
e
ss than the
NO
x conve
r
satio
n
rate
C
NOx
of scheme
3.
Not
only su
ch, a
s
the ab
solute t
i
me of t
lean
/t
ric
h
diminishing, t
he NOx co
nversi
on
rate
C
NO
x
of the thre
e
scheme all in
cre
a
se, the NOx conve
r
sio
n
rate C
NOx
schem
e 1 enla
r
ge
s from 6
1
.9% (200
s: 20
s)
to 83.5% (40
s
: 4s); the NOx conversio
n
rate C
NOx
of sch
eme 2 en
large
s
from 7
0
% (200
s: 20
s) t
o
85.2% (40
s
: 4s); a
nd the
NOx co
nversi
on rate
C
NOx
x of schem
e 3 enlarge
s
from 94% (20
0
s:
20s) to 9
7
.3
%(40
s: 4s). T
he NOx conv
ersi
on
rate
C
NO
x
of sch
em
e 3 i
s
better than the
othe
r two
scheme
s
; it is mainly beca
u
se of the di
fferent a
rra
nge
ment of the catalysts.
3. 2 The Effe
ct of
Differe
n
t Speed
s on Ex
haus
t Emission Cha
r
acteristic
s
and BSF
C
As ab
ove, schem
e 3
is
the be
st
sch
e
me
amo
ng sc
h
e
m
e
1 to
sc
he
me
3
.
U
n
d
e
r
scheme 3, th
e author
stud
ied the effect of di
fferent operatio
ns o
n
BSFC and ex
hau
s
t emissi
on
cha
r
a
c
teri
stics. Figure 4
and Figu
re
5 sho
w
the
effect of exhaust emi
s
sio
n
and the
NOx
conve
r
si
on ra
te
C
NOx
in scheme
3 o
n
di
fferent spee
d
s
(150
0 rpm,
1800
rpm, 2
500
rpm
)
u
n
d
e
r
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TELKOM
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Vol. 11, No. 3, September 20
13: 48
1 – 488
484
the load
bein
g
co
nsta
nt. The x-axis den
otes the
ratio
of the ab
sol
u
te lean
burn
operating ti
me
t
lean
and the absolute ri
ch
con
d
ition op
e
r
ating time t
rich
. The y-axis
denote
s
the
concentratio
n
o
f
exhau
st emi
s
sion
in
clude
CO,
HC an
d
NOx (1 x 1
0
-6
),
the NOx co
nversi
on rate
C
NOx
(%
) and
the
BSFC res
p
ectively.
Operating
co
ndition
s an
d
mode
of the l
ean b
u
rn ga
soline e
n
gin
e
are: lo
ad
(PM
EP) Pe=
0.2 MPa, spe
ed are 150
0 rpm,1800
rpm
,
and 2500
rp
m
respe
c
tively. A/F in lean burn i
s
21, a
n
d
that of
rich
b
u
rn
is 12
,
t
le
an
/t
ric
h
= 10. As sho
w
n in F
i
gure 4, wh
e
n
the ratio of t
lea
n
/ t
rich
and the
absolute time
of t
lean
/ t
ri
ch
keep stea
dy, as the spe
ed of gasoli
ne e
ngi
ne incre
a
se
d
( Pe= 0.2 M
p
a,
the sp
eed a
r
e 150
0 rpm,
1800
rpm, an
d 250
0 rpm
resp
ectively), i
n
the ex
hau
st
emission
of the
lean bu
rn ga
solin
e engin
e
,
the CO,HC
redu
ce a
nd NOx incre
a
se slightly. But
with the abso
lute
time of t
lea
n
/ t
ri
ch
decrea
s
ed.
(a)
(b)
(c
)
Figure 4. Effects of differe
n
t
speed
s
on e
x
haust emi
ssi
on (Pe
=
0.2 MPa)
(a) Effects of different spee
ds on CO
emissi
o
n
, (b) Effects of different spe
e
d
s on HC em
is
sion
(c) Effects of different spee
ds on NO
x emissi
on
The
CO
an
d
HC in
crea
sed b
u
t NOx
decrea
s
e
d
sli
g
htly. This is mainly
be
ca
use
the
spe
ed of the lean bu
rn ga
solin
e engin
e
incre
a
sed,
which ma
de th
e oxygenou
s con
d
ition in the
cylinde
r bett
e
r, that’s b
e
tter to the su
fficient
oxidat
ion of CO
a
nd HC, so t
he CO and
HC
emission
of t
he le
an b
u
rn
ga
soline
en
gine
de
cre
a
sed. Becau
s
e
the en
gine
a
d
opt the
the l
ean
burn
NOx ad
sorbe
r
-red
uct
i
on catalyst system, the
co
nce
n
tration
of
CO
and
HC
in the emi
s
si
on
of the lean
b
u
rn
ga
soline
engin
e
is
a li
ttle highe
r th
an that of p
u
r
e le
an b
u
rn
gasoline
engi
ne
.
After the
spe
ed of e
ngin
e
increa
se, i
n
the ad
so
rb
e
r
-redu
ction
proce
s
s of le
a
n
bu
rn
ga
soli
ne
engin
e
, beca
u
se the time ratio of lean burn a
nd ri
ch
burn t
lean
/ t
ric
h
is a consta
nt, the times
of
engin
e
o
peration
cycle
in t
h
e same
pe
rio
d
in
crea
sed,
whi
c
h
will
ma
ke th
e tem
perature
in
side
the
cylinde
r a little highe
r a
nd t
he con
c
entration of NOx
incre
a
sed. But
with the ab
sol
u
te time of t
lea
n
/
t
rich
decre
ase
d
, the times o
f
A/F transformed p
r
o
c
e
ss
in the sa
me p
e
riod i
n
crea
sed an
d the to
tal
time of engin
e
ope
ration i
n
tran
sitional
period i
n
cre
a
se
d, so the
CO and
HC emission of
the
engin
e
incre
a
s
ed. As th
e d
e
crea
se of t
lean
and t
rich
improved th
e conversion
rat
e
of NOx C
NO
x
in
ads
orb
e
r
-
r
e
d
u
ct
ion
cat
a
ly
st
sy
st
e
m
,
so
t
he NOx
e
m
issi
on
d
e
crea
sed with
the decrea
se of
the
absolute time
of t
lea
n
and t
ri
ch
.
As sho
w
n i
n
Figure 5,
wh
en the
ratio
of t
lean
/ t
ric
h
keep
stea
dy ,the
conve
r
si
o
n
rate
of
NOx
C
NOx
reache
d 94.2% whe
n
t
lean
/ t
ric
h
= 200: 20(n
=
150
0 rpm
)
. With the increa
se of engi
ne
spe
ed (C
NOx
= 9
4
%
whe
n
n=
180
0 rpm
,
and
C
NOx
= 93.8% when
n=
2500
rp
m), the co
nversi
on
rate
of NOx
C
NOx
change
d
little. This is
mainly be
cau
s
e th
e NOx will
in
cre
a
se with
the spe
e
d
of
engin
e
in
crea
sed,
but the
tempe
r
atur
e o
f
exhau
st into
the
catalyst
system
ri
se
what is the
bette
r
for imp
r
ove th
e oxygeno
us
con
d
ition of t
he
cataly
st
sy
stem a
nd th
e
worse
for the
resto
r
e
of
NO
x
emission.
Wh
en the ratio o
f
t
lea
n
/ t
rich
keep steady, the conve
r
si
on ra
te of NOx C
NOx
ris
e
with the
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TELKOM
NIKA
ISSN:
1693-6
9
30
Red
u
ce NO
x
Em
ission
s by Adsorber-Re
ductio
n
Catal
yst on L
e
an B
u
rn Engi
ne (Don
gpe
ng Yu
e)
485
decrea
s
e of t
lean
/ t
rich
absol
ute time (for example : t
lea
n
/ t
ri
ch
decrea
s
e from 20
0: 20 to 40: 4).This
is b
e
cau
s
e th
at the d
e
crea
se
of t
lean
/ t
ric
h
absolute
time redu
ce
d t
he le
ak of
NOx thro
ugh l
e
an
burn
ad
so
rbe
r
-redu
ction
catalyst syste
m
and i
m
pro
v
ed the a
d
so
rbility of NOx
emissio
n
. T
he
NOx emi
s
sio
n
of lean
bu
rn ga
solin
e en
gine
whi
c
h
h
a
s
rise sli
ghtl
y
due to the i
n
crea
se
of sp
eed
can
be
imp
r
o
v
ed by
sho
r
ten the
t
lean
/ t
ri
c
h
absolute ti
me. So if the
t
lean
/ t
ric
h
a
b
s
o
l
u
t
e
time
k
eep
steady, the conversion
rat
e
of NOx C
NO
x
in adso
r
be
r-redu
ction
cataly
st
sy
st
e
m
redu
ce
a lit
t
l
e
with the spe
ed of engi
ne
rise. O
n
the
contrary, the
conve
r
si
on rate of NOx
C
NOx
in adsorber-
reduction
cat
a
lyst system
will ri
se a littl
e if
de
cre
a
se
the t
lean
/ t
ri
ch
absolute time
. That is me
a
n
s
that the incre
a
sin
g
NOx exhau
st emissio
n
with
the risi
ng of spee
d can
be improved by decrea
s
e
of t
lean
/ t
ri
ch
absolute time.
Figure 5. Effects of differe
n
t
s
peed
s on
NOx co
nversi
on efficien
cy C
NOx
(Pe=0.2
MPa)
Figure 6. Effects of differe
n
t
speed
s on B
S
FC
(
Pe=
0
.2MPa)
As sh
own in
Figure 6, wh
e
n
t
lean
/ t
rich
an
d the ab
solut
e
time of t
lean
/ t
rich
keep ste
a
d
y, if the
spe
ed
of en
gine
rise(fro
m 150
0
rpm
to 25
00
rp
m), BSFC
be
imp
r
oved.
In other words, the
speed ri
sed. But the BSFC will
rise a
l
i
ttle with the absolute time of t
lean
/ t
rich
r
e
du
ce. Analy
z
ing
this phen
ome
non, we de
e
m
that : when t
lea
n
/ t
rich
keep
steady, if the
absolute tim
e
of t
lea
n
/ t
rich
st
a
y
the sam
e
, the turbul
en
ce
intensity in
sid
e
cyli
nde
r of
the lean b
u
rn
gasoline e
n
g
ine
will larg
en
and th
e
com
bustio
n
con
d
i
t
ion will
be
b
e
tter
what l
e
ad to
the
sm
aller BSFC.
But if
the
spe
ed
of
engin
e
is mu
ch too hig
h
, the BSFC will
gro
w
the
bigg
er be
cau
s
e t
hat the stren
g
then movem
ent
of air i
n
si
de t
he
cylinde
r le
ad to th
e tra
n
sferre
d lo
ss of the
qua
n
tity of heat in
side the
cylind
e
r.
The ra
nge
of spee
d in thi
s
expe
riment
belong to th
e middle a
n
d
lowe
r ra
nge
of the engin
e
spe
ed,
so th
e ri
se
of spe
ed le
ad to th
e BSFC
de
creased. As th
e ab
sol
u
te ti
me of t
lean
/ t
rich
decrea
s
e, b
e
c
au
se t
lean
/ t
ric
h
stays at a consta
nt that
the pe
rcentag
e
of the total time of the sa
me
lean bu
rn g
a
soline en
gine
operating in l
ean bu
rn a
n
d
rich
burn co
ndition stay
s
at a con
s
tant
but
the times of
A/F transfo
rm
ing proc
ess i
n
the sam
e
p
e
riod i
n
crea
sed and th
e total time of engine
operate in tra
n
sition
al pe
ri
od incre
a
sed
what la
r
ge th
e BSFC of le
an bu
rn ga
sol
i
ne engi
ne a l
i
ttle
althoug
h not notable.
These result can
be expl
a
i
n as
(comp
a
r
ed to fo
ll
owi
ng loa
d
facto
r): the im
pa
ct of the
increa
se of le
an bu
rn g
a
so
line en
gine
speed
on
the
exhau
st emission
and BS
FC of le
an b
u
rn
gasoline
engi
ne have to
d
o
with the
ra
tio and a
b
sol
u
te time of t
lean
/ t
ri
ch.
Whe
n
t
lean
/ t
ric
h
keep
steady, if the
ab
solute tim
e
of t
lean
/ t
rich
stay the
sa
me, with th
e
spe
ed of
eng
ine in
crea
se,
the
con
c
e
n
tration
of CO an
d
HC
will de
crease and th
at
of NOx in
cre
a
se a little. But with the
absolute time
of t
lea
n
/ t
rich
d
e
crea
se, the
con
c
e
n
tration
of CO and
HC
will incre
a
se a
n
d that
of
N
O
x decr
ease a little. When t
lean
/ t
ric
h
k
e
ep s
t
eady, if the abs
o
lute time of t
lean
/ t
ric
h
s
t
ay the same,
with the spe
e
d
of engine in
cre
a
se(from 1500 rpm
to 2500 rpm), the conve
r
si
on rate of NOx C
NO
x
in ad
sorbe
r
-redu
ction
cata
lyst sy
stem
d
e
crea
sed littl
e, althoug
h it’s not n
o
table
.
And the BSFC
of lean burn
gasoline e
ngi
ne turn b
e
tter what me
a
n
s
that the spee
d increa
sed a
n
d the BSFC
of
lean bu
rn
ga
solin
e engi
ne
decrea
s
e
d
. If the absolu
t
e time of t
le
an
/ t
ric
h
decre
ase
d
, both the
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
9
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TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 48
1 – 488
486
conve
r
si
on rate of NOx C
NOx
and the BSFC in ad
sorbe
r
-red
uct
i
on cataly
st system wo
uld
be
largen.
3. 3 The
Ef
fe
ct of
Diff
ere
n
t
Lo
ads on
Exhaus
t Emission Ch
ara
c
teris
t
ics an
d BSFC
Figure 7,
Fig
u
re
8, an
d Fi
gure
9
sh
ows the
effec
t
of
exhaus
t
emis
s
i
on CO, HC,
NOx,
the co
nversio
n
rate
of NO
x C
NOx
and the BSFC
at
the sp
eed
of
1800
rp
m in
schem
e 3
o
n
different l
oad
s
(pe
=
0.2 M
P
a, 0.3
MPa,
and
0.4 MPa
)
. the A/F
ratio
of lea
n
burn i
s
2
1
, the
A/F
of
r
e
d
u
c
t
io
n
pr
oc
es
s
is
12
, t
le
an
/ t
ri
c
h
= 10.
(a)
(b)
(c
)
Figure 7. Effects of differe
n
t
loads
on ex
hau
s
t emissio
n
(n=
1800
rp
m)
(a) Effects of different loads
o
n
CO
emissio
n
,
(b) Effects of
different lo
ads
on HC em
issio
n
(c) Effects of different loads
o
n
NO
x emiss
i
o
n
As sh
own in
Figure 7, wh
en t
lean
/ t
rich
keep ste
ady, if the absol
ute
time of t
le
an
/ t
rich
st
ay
the sam
e
, with the load of
engin
e
increa
se(0.2
MPa, 0.3 MPa, and
0.4 MPa), the CO an
d HC
will decre
ase
and that of NOx incre
a
se
. But with the
absolute time
of t
l
ean
/ t
ric
h
d
e
crea
se, the CO
and HC will increa
se an
d that of NOx decrea
s
e a littl
e. This is mai
n
ly becau
s
e t
hat the increa
se
of engine lo
a
d
heighte
n
the temperature insid
e
the cylinde
r of the lean bu
rn
gasoline en
gi
ne
what
enh
ance the fu
el o
xygenation
competently
,
and th
e in
crease of
cyli
nder inn
e
r
wall
temperature
decrea
s
e
d
th
e thickne
s
s o
f
the layer
attach
ed to the
wall of
cylind
e
r, so th
e am
ount
of HC a
d
sorb
ed by the layer attached t
o
the wall
of
cylinde
r de
creased. At the same time, t
h
e
increa
se
of lo
ad, de
crea
se
the unf
i
r
ed
of
fuel mixture
i
n
the
cylind
e
r. As a
result, the CO
and
HC
will redu
ce
when the
load
i
n
crea
se, me
a
n
whil
e, t
he in
cre
a
se of lo
a
d
and
tempe
r
ature i
n
si
de t
h
e
cylinde
r
we
re
favora
ble to
the fo
rmation
of NOx,
so
as to
N
O
x inc
r
ea
s
e
; if th
e loa
d
k
e
ep
s
t
e
a
d
y
,
when the abs
o
lute time of t
lean
/ t
ri
c
h
de
crease,
the CO and
HC will
increase and
that of
NOx
decrea
s
e. T
h
is is
be
cau
s
e
the de
cr
ea
se of the ab
so
lute time of t
lean
/ t
ri
ch
short
en the le
ngth
of
lean bu
rn tim
e
that the lean burn catal
y
st syst
em u
n
dergo
(
mayb
e the catalyst system ha
sn’t
adsorb to saturation
), after that the restore an
d reg
e
neratio
n pro
c
ess in rich b
u
rn atmo
sp
h
e
re
started,
the ti
me of th
e en
gine
ope
rate
d in th
e tra
n
s
ition
co
nditi
on d
u
rin
g
th
e same tim
e
-lag
increa
sed ,which ma
de the co
ncentration of
CO
and HC a
little bigger, but the NOx
con
c
e
n
tration
became
sm
aller, it’s
be
cause that un
der favo
r of
t
he de
crea
se
of the ab
solu
te
time of t
lean
/ t
ri
c
h
,
the NOx
whi
c
h
cre
a
te
d in the p
r
o
c
ess of lea
n
b
u
rn
(which ha
s ab
so
rbe
d
i
n
the
catalyst by th
e alkaline
ea
rth in the l
e
a
n
bur
n NOx adsorb
e
r and
re
store catal
y
st
system a
n
d
stora
ged
in t
h
e form
of nit
r
ate)
co
nverte
d to
N
2
a
b
solutely in the
re
store
atmo
sp
here,
and
in
the
alkali
ne earth of the lean burn
NOx adsorb and re
store catalyst sy
stem had no
NOx left. All of
these in
crea
sed the ad
sorb cap
ability of lean burn
catalyst for NOx in the lean burn
con
d
ition,
that means th
e conve
r
si
on
rate of NOx C
NO
x
in adsorb
e
r-red
u
ctio
n
c
a
t
a
ly
st
incr
ea
sed.
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TELKOM
NIKA
ISSN:
1693-6
9
30
Red
u
ce NO
x
Em
ission
s by Adsorber-Re
ductio
n
Catal
yst on L
e
an B
u
rn Engi
ne (Don
gpe
ng Yu
e)
487
As sho
w
n a
s
Figure 8, the conve
r
si
on rate of NOx C
NOx
in adsorber-re
du
ction
catalyst
system
have relation with
not
only the absol
ute time of t
lean
/ t
ri
c
h
but also the loa
d
of the engine
in
the ad
so
rbe
r
-redu
ction
cat
a
lyst sy
stem.
The
big
ger t
he lo
ad, the
highe
r the
NOx emi
ssi
on,
and
the lo
wer the
co
nversion
rate of
NOx
C
NO
x
.when t
lean
/ t
rich
keep
st
eady, if the
a
b
sol
u
te time
of
t
lean
/ t
rich
stay the sa
me, wit
h
the lo
ad of
engin
e
in
cre
a
s
e(n= 18
00 rpm,
pe
i
s
0.2
MPa, 0.3 M
P
a,
and 0.4 MP
a
respe
c
tively), the conve
r
si
on rate
of NOx C
NOx
decrease. Wh
en l
oad i
s
0.2 M
P
a,
the C
NOx
is 94%; when
loa
d
is 0.3
MPa, the C
NOx
is 85%; when
loa
d
is 0.4
MPa, the C
NOx
is onl
y
49% (when t
le
an
/ t
ric
h
= 200:
20). Comp
are
d
with the in
crea
se of the
C
NOx
cause
d
by the de
cre
a
s
e
of the adsorber-re
du
ctio
n
cat
a
ly
st
sy
st
em’s a
b
s
o
lut
e
t
i
me of
t
lea
n
/ t
rich
, the load of lean
b
u
rn
gasoline e
ngi
ne have m
u
ch more influe
nce
on the
C
NO
x
. The bigger the l
oad,
the small
e
r t
he
C
NOx
. Fortun
ately, lean burn conditio
n
mainly work
in the opera
t
ing con
d
ition
with middle
and
low spee
d an
d part load.
As sh
own in
Figure 9, the
load of en
gin
e
ha
s more i
n
fluen
ce on t
h
e BSFC. Th
e bigge
r
the load, th
e better. Thi
s
is b
e
cau
s
e with the l
o
ad of en
gi
ne incre
a
se, the com
b
u
s
tion
temperature
in the
cylind
e
r
rise, on
the o
ne
ha
n
d
,
the a
c
creti
o
n of l
oad
i
m
prove
the f
uel
pulveri
zation
what imp
r
ove
the combu
s
t
i
on co
nditi
on;
on the other hand, the accretio
n of loa
d
decrea
s
e
the
engin
e
relati
vely coolin
g l
o
se
and
pum
ping lo
se, th
e
therm
a
l effici
ency of
engi
n
e
rise. Be
side
s,
the accretion
of load improves t
he me
chani
cal efficie
n
cy of engin
e
.
The accretio
n
of load improved the the
r
mal efficie
n
cy and the
mech
ani
cal efficien
cy, that made the B
S
FC
better .
Figure 8. Effects of differe
n
t
loads on
NO
x c
onversion efficien
cy
CNOx (n= 1
800
rpm)
Figure 9. Effects of differe
n
t
loads on BS
FC (n
=1
800 rpm)
Whe
n
t
lean
/ t
ri
ch
keep
steady
, if the load stay the sa
me,
with the ab
so
lute time of t
le
an
/ t
ri
ch
decrea
s
e, B
S
FC ri
se
a li
ttle, what du
e to t
hat the
decre
ase of
the ab
solute
time of t
lean
/ t
rich
large
n
the total time of engine wo
rks in tran
sitional o
p
e
rating
con
d
ition in the sa
me time-lag.
4. Conclusio
n
Applying th
e
new catalyst
system
comp
ose
d
of
tradit
ional th
re
e
way cataly
st
converte
r
and ad
sorbe
r
-re
du
ction ca
talyst
co
nvert
e
r whi
c
h
is desi
gne
d
by author studie
d
the
effect of
different
sch
e
mes of
cata
lyst co
nverte
r a
r
rang
eme
n
t and
different spee
ds a
nd lo
ad
s o
n
the
exhau
st emi
s
sion
characte
ristic
s
and
BSFC of
a lea
n
bu
rn
ga
soli
ne e
ngine,
we got th
e ma
in
con
c
lu
sio
n
s b
e
low:
1.
Und
e
r th
e
co
ndition of th
e
s
e
experim
en
ts, cata
ly
st co
nverter arran
gement
sche
me 3
whi
c
h i
s
desi
gne
d by author
ca
n achieve the
lowes
t
NOx emiss
i
on of 50 10
-6
and the con
v
ersio
n
rat
e
of is the hig
h
e
st to 97.3%.
T
herefore, when we
u
s
e
l
e
an
b
u
rn ad
sorbe
r
catalyst
combi
ned
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 48
1 – 488
488
with three
ways catalyst to reduce
NOx
em
ission in l
ean
burn S.I. engi
ne, the
scheme that
the lean bu
rn
NOx ad
sorbe
r
-redu
ction
ca
talyst is arran
ged after the
TWC sh
ould
be ado
pt.
2. Whe
n
t
lean
/ t
ric
h
kee
p
stead
y, if the ab
so
lute time
of t
lean
/ t
rich
stay the
sam
e
, a
s
the spee
d o
f
gasoline
engi
ne in
crea
sed,
in the
emissi
on of
le
an b
u
r
n g
a
soline
e
ngine, the
CO, HC redu
ce
and NOx in
crease slightly, the BSFC
be
improved.
But the chan
ge of the con
v
ersio
n
rate
of
NOx i
s
n
o
t n
o
table.
With t
he a
b
solute ti
me of t
lean
/ t
ric
h
decre
ased, the
con
c
entra
tion
of NOx
emission d
e
crea
sed a little
,
and the con
v
ersio
n
rate o
f
NOx C
NOx
la
rgen, so is th
e BSFC .
3. Whe
n
t
lean
/ t
ric
h
keep
stead
y, if
the abso
l
ute time of t
lean
/ t
rich
stay the sa
me, wit
h
the load of
engin
e
in
cre
a
se
s, the
CO an
d
HC
will de
cre
a
se
and th
at of
NOx in
crea
se. But with
the
absolute time
of t
lean
/ t
ric
h
decrea
s
e, the
CO a
nd HC
will incre
a
se and that of NOx decrea
s
e
a
little, the conversi
on rate of NOx C
NOx
increa
sed a
nd th
e BSFC
be
g
o
to bad.
4. The
C
NOx
have rel
a
tion
with not o
n
ly the ab
solute
time of t
lean
/ t
ric
h
but al
so the
magnitu
de o
f
the engin
e
lo
ad. The big
g
e
r the loa
d
, the high
er
NO
x emissio
n
, a
nd the lower t
he co
nversion
rate of NOx
C
NOx
, but the BSFC
be
im
proved in l
e
a
n
burn NOx
adsorb
e
r-red
u
ction
catalyst
sy
st
em.
Ackn
o
w
l
e
dg
ements
This stu
d
y
wa
s
sup
port
ed by th
e
Nation
Nature Scie
nce
Found
ation
of Chi
n
a
(502
760
42, 5
0776
062, 51
2761
28), the
Nation
al Hig
h
Tech
nolo
g
y Re
sea
r
ch an
d Develo
pme
n
t
Program of Chin
a
(863
Program)
(2
008AA06Z
32
2), an
d the
Tianjin
Re
se
arch Prog
ra
m of
Applicatio
n F
ound
ation an
d Advanc
e
d
Tech
nolo
g
y (11JCZ
DJC2
3
200).
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n
d
o
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i Ku
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Z
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