An Experimental Study of PM Emission Characteristics of Commercial Diesel Engine with Urea-SCR System
Chunhwan Lee, Deokjin Kim, Kwangchul Oh, Chunbeom LeeEnvironmental Parts R&D Center, Korea Automotive Technology Institute (KATECH)
Undesirable particles come from Urea-SCR :Ammonium Sulfate, Ammonium Nitrate, New polymer Complex(by HNCO base), etc
Weight and Number of PM deeply depend on the Urea injection strategy & Urea Injection System Design
ConclusionsConclusions
Environmental Parts R&D Centerhttp://eprc.katech.re.kr Korea Automotive Technology Institute
SCR & Variable DilutorThermodenuder
ELPI & FPS
injector
NH4
HSO4
(NH4
)2
SO4
NH4
NO3
+ NH4
NO2
2SO3
→
→
NH3 + SO3
+ H2
O
2NH3 + SO3
+ H2
O
Ammonium Sulfate Formation :
→2NH3 + 2NO2
+ 2H2
O
Ammonium Nitrate Formation :
→2SO2
+ O2
SO2
Oxidation :
Particle Size DistributionSystem Configuration: DOC+DPF+Vanadium SCR, ELPI@ 1200rpm, 640Nm, 380℃, T.D=275℃, Adblue: 20g/min
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
0.01 0.1 1 10
Size (um)
Num
ber (
1/cm
^3)
Base No injU4.7A1U4.7A2U4.7A2.5U4.7A3U4.7A3.5U4.7A4
water
Fresh
W/O Urea
W/ Urea
TGA/DSC TEMFTIR spectrum
600oC
W/ Adblue
injection
Urea from Adblue
Soot particle
0 100 200 300 400 500 600
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
-7
-6
-5
-4
-3
-2
-1
0
1
~415oC
~370oC
~345oC
~240oC
TGA
, m/m
o
Urea from Adblue Texh=380oC, Adblue injection
~145oC
DS
C
Temperature, oC
W/ Adblue
injection
Urea from Adblue
Urea (4.5bar)+Air(3bar)Urea (4.5bar)+Air(3bar)
Particle Size DistributionSystem Configuration: DOC+DPF+Vanadium SCR, ELPI
@ 1200rpm, 640Nm, 380℃, T.D=275℃, U : 4.5bar A : 3bar, Adblue
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
0.01 0.1 1 10
Size (um)
Num
ber (
1/cm
^3)
0g
7.5g/min
15g/min
20g/min
27.5g/min
37.5g/min
CPC Concentration NumberSystem Configuration: DOC+DPF+ Vanadium SCR, ELPI
@ 1200rpm, 640Nm, 380℃, T.D: 275℃, U : 4.5bar, A : 3bar, Adblue
0
5000
10000
15000
20000
25000
1 51 101 151 201 251 301 351Time (s)
Num
ber (
1/cm
^3)
1200rpm, 640Nm, 380℃, T.D: 275℃, U : 2bar, A : 1bar, Adblue
Particle Size DistributionSystem Configuration: DOC+DPF+ Vanadium SCR, ELPI
@ 1200rpm, 640Nm, 380℃, T.D: 275℃, U : 2bar, A : 1bar, Adblue
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
0.01 0.1 1 10
Size (um)
Num
ber (
1/cm
^3)
0g/min7.5g/min15g/min20g/min27.5g/min37.5g/min
CPC Concentration NumberSystem Configuration: DOC+DPF+ Vanadium SCR, ELPI
@ 1200rpm, 640Nm, 380℃, T.D: 275℃, U : 2bar, A : 1bar, Adblue
0
2000
4000
6000
8000
10000
12000
1 51 101 151 201 251 301 351 401 451Time (sec)
Num
ber (
1/cm
^3)
1200rpm, 640Nm, 380℃, T.D: 275℃, U : 2bar, A : 1bar, Adblue
Urea (2bar)+Air(1bar)Urea (2bar)+Air(1bar)Injection
Pressure
0g
7.5g
15g20g
27.5g37.5g
0g
7.5g
15g20g
27.5g
37.5g
Background-
Diesel engine: excellent fuel economy benefit, “Fun-to-Drive”
High Torque-
But, the regulation of emission: PM, NOx various Aftertreatment system -
NOx
: Utilization of SCR system using urea solution
as a reductant
Experiment1.
the experiment of a diesel engine equipped with Urea SCR system, and its emission characteristic including particle is analyzed and evaluated against its regulation.
2.
Measurement of PM: Diluter + Thermodenuder
+ ELPIunder various conditions of engine RPM and load (Particle number distribution of size range from 7nm to 10μm
Results:1. The particle number was increased in the proportion of amount of urea injection2. The increase of Fine particle range(< 2.5μm) was remarkable 3. The effect of thermodenuder
and engine exhaust temperature(250oC~450oC) is almost negligible for the change of particle number distribution
tendency4. But Increase of injection pressure (1bar~4bar) of Urea solution :
Fine particle (~1μm): Decrease of number of particle While, Ultra Fine particle(< 100nm) and Nano
particle(< 50nm) range: Increasing tendency 5. This particles: include new complex matter from urea decomposition process on SCR
catalysts and most dry-Urea FTIR , TGA/DSC, TEM.
Abstract
Experimental Setup
TEM Photograph
Chemistry
① [(NH2)2CO, 7H2O]n→ [(NH2)2CO]n + 7H2O ( >135℃ )
② Thermolysis[(NH2)2CO]n → NH3 + CO2[(NH2)2CO]n → HNCO + NH3
③ Hydrolysis(NH2)2CO + H2O 2NH3 + CO2
HNCO + H2O → NH3 + CO2
※ 3HNCO → [(HNCO)3]s ( <350℃ )
④ Fast Reaction : 4NO + 4NH3 + O2 → 4N2 + 6H2OSlow Reaction : 2NO2 + 4NH3 + O2 → 3N2 + 6H2OVery Fast Reaction : NO + NO2 + 2NH3 → 2N2 + 3H2O
⑤ 4NH3 + 3O2 2N2 + 6H2O
※ 2NO + O2 → 2NO2
Nano
PMNumber Distribution
Nano
PMNumber Distribution
Nano
PM Increase ▲
Urea Solution Injection
Nano
PM Increase ▲
Urea Solution Injection
Characteristicsof Particle
Characteristicsof Particle
Emission Regulations (EURO-IV)1.
Advanced FIE & Combustion2.
Urea-SCR System
Emission Regulations (EURO-IV)1.
Advanced FIE & Combustion2.
Urea-SCR System
White PM & PM Weight IncreaseWhite PM & PM Weight Increase
Particle distribution
Fine particle
Nanoparticle Fine particle
Effect of Injection Pressure
TGA/DSC FTIR spectrum
4000 3000 2000 10000.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
abso
rpvi
ty
wave number, cm-1
KBr T=600oC PM1 PM2 Urea
CO2
1120
1400
1630
PM weight-
ESC
base no urea w/ urea0.000
0.005
0.010
0.015
0.020
0.025
PM
, g/k
wh
case
Diesel BD20 BD5 BD05
0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 1 6 0 0 1 8 0 0
8 x 1 0 2
2 x 1 0 3
2 x 1 0 3
3 x 1 0 3
4 x 1 0 3
5 x 1 0 3
6 x 1 0 3
6 x 1 0 3
7 x 1 0 3
8 x 1 0 3
Num
ber d
ensi
ty(n
/cm
3 )
T im e (s e c )
w /o S C R w S C R u re a 9 0 % u re a 1 2 0 %