investigation of the feasibility of achieving euro vi heavy-duty
TRANSCRIPT
Investigation of the Feasibility of Achieving Euro VI Heavy-Duty Diesel Emissions Limits
by Advanced Emissions Controls
D Bosteels, J MayAECC – Association for Emissions Control by Catalyst, Belgium
A J Nicol, C H Such, J D Andersson, R D SellersRicardo UK Ltd
2
Contents
• Objectives and project details- Test engine and system- Optimisation potential- Protocols
• ETC & WHTC Results- Regulated emissions- Particle number- Conversion efficiencies- Effect of cold start and soak period- Elemental Carbon and PAH emissions
• Key results from all cycles• Summary
3
Objectives of AECC heavy-duty Euro VI test programme
• Demonstrate the performance of an integrated emissions control system on a modern, low NOx engine.
• Provide data on regulated and non-regulated emissions.• Compare current gravimetric and heavy-duty PMP method
for particulate mass (PM).• Assess heavy-duty PMP particle number methodology.• Provide data on European and World-harmonised transient
and steady-state test procedures.
4
AECC heavy-duty Euro VI test engine
• Engine designed for US2007, provided by an engine manufacturer- 6 cylinder 7.5 litre engine- Common rail- Turbocharged (fixed vane)- Max. injection pressure 180Mpa- Cooled lambda-feedback EGR - Original particulate filter replaced by AECC system.
• No modification to base engine calibration- no changes made to optimise engine-out emissions
on the European cycles- engine-out emissions are ‘as received’.
5
Emissions control system for AECC heavy-duty Euro VI test programme
• Oxidation catalyst (DOC), catalyst-based wall-flow particulate filter and urea-SCR with ammonia slip catalyst (ASC).
• System oven aged for 200hours at 600oC. • Bosch advanced airless urea dosing system.• NOx sensors at engine-out and downstream of the SCR
system (upstream as input for dosing control, second as monitor; not for closed loop control).
• No optimisation was undertaken.
7,5 l 14 l 14 l
Urea
3,5 l
Engine SCRC-DPF ASC
3,8 l
DOC
Mixer1m mixing length between injector and SCR face.
6
Testing and Preconditioning procedures • Triplicate tests were carried out for tailpipe emissions on
each of the test cycles. Average results are presented.• Single additional tests were used to measure engine-out
PM, particle number and some speciation analyses.• For repeatability, each day started with a cold start test.• Standard end-of day preconditioning was:
- mode 4 warm-up: 15 min. 2130 rev/min. 560 Nm- followed by: 60 min. 2575 rev/min. 700 Nm- then: 60 min. 1300 rev/min. 150 Nm
• Following each test cycle the engine was run at a Mode 4 standardisation condition for 15 minutes.
• Pre-test conditioning for hot cycles was:- ETC, ESC: 7.5 min. mode 4 (2130 rev/min, 560 Nm)- WHSC: 10 min. mode 9 (1816 rev/min, 373 Nm)
followed by 5 min. soak.
7
ETC results for engine-out and tailpipeg/
kWh
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
NOx THC CO/10 PM
Engine OutTailpipe
Euro V PM limit 0.03g/kWh
Euro V limit(NMHC)
Euro V NOx limit
Euro V CO limit
0
1
2
3
4
5
6
7
8
9
10
PM
mg/
kWh
Euro VPM limit
30mg/kWh
8
ETC and WHTC testsCO & HC emissions, engine-out and tailpipe
ETC, tailpipeETC, engine-0ut WHTC, tailpipeWHTC, engine-0ut
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
ETC WHTC (5 min hot soak,10% cold weighting)
CO
[g/k
Wh]
Euro V limit
90% conversion
79% conversion
0.0
0.2
0.4
0.6
0.8
1.0
ETC WHTC (5 min hot soak,10% cold weighting)
Tota
l HC
[g/k
Wh]
Euro V NMHC limit
63% conversion
69% conversion
9
ETC and WHTC testsNOx emissions for engine-out and tailpipe
ETC, tailpipeETC, engine-0ut WHTC, tailpipeWHTC, engine-0ut
0.0
0.5
1.0
1.5
2.0
2.5
ETC WHTC (5 min hot soak, 10% cold weighting)
NO
x [g
/kW
h]
Euro V limit
86% conversion
76% conversion
10
ETC and WHTC testsPM emissions for engine-out and tailpipe
ETC, tailpipeETC, engine-0ut WHTC, tailpipeWHTC, engine-0ut
Measurements using partial flow (mini-dilution tunnel) system
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
ETC WHTC (5 min hot soak,10% cold weighting)
Par
ticul
ate
Mas
s [g
/kW
h]
99.8% conversion
99.7% conversion
0.0
2.0
4.0
6.0
8.0
10.0
ETC WHTC (5 min soak,10% cold weighting)
Par
ticul
ate
Mas
s [m
g/kW
h]
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
ETC WHTC (5 min hot soak,10% cold weighting)
Par
ticul
ate
Mas
s [g
/kW
h]
99.8% conversion
99.7% conversion
0.0
2.0
4.0
6.0
8.0
10.0
ETC WHTC (5 min soak,10% cold weighting)
Par
ticul
ate
Mas
s [m
g/kW
h]
0.0
2.0
4.0
6.0
8.0
10.0
ETC WHTC (5 min soak,10% cold weighting)
Par
ticul
ate
Mas
s [m
g/kW
h]
0.0
2.0
4.0
6.0
8.0
10.0
ETC WHTC (5 min soak,10% cold weighting)
Par
ticul
ate
Mas
s [m
g/kW
h]
11
PMP particle number results for ETC & WHTC• Particle measurements WERE MADE according to the latest draft of the
heavy-duty PMP inter-laboratory correlation exercise guide
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
ETC
part
icle
s/kW
h
Engine-outTailpipe
• ETC tailpipe emissions ~ 4 x 1011/kWh • DPF Efficiency > 99.9%
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
weighted WHTC
parti
cles
/kW
h
Engine-outTailpipe
• WHTC tailpipe emissions < 5 x 1011/kWh • DPF Efficiency > 99.8%
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
ETC
part
icle
s/kW
h
Engine-outTailpipe
• ETC tailpipe emissions ~ 4 x 1011/kWh • DPF Efficiency > 99.9%
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
weighted WHTC
parti
cles
/kW
h
Engine-outTailpipe
• WHTC tailpipe emissions < 5 x 1011/kWh • DPF Efficiency > 99.8%
WHTC (5 min. hot soak, 10% cold weighting)
12
Conversion efficiencies for ETC and WHTC
Non-optimised system – no thermal managementWHTC (5 min soak,10% cold weighting)
76%
86%
69%63%
79%
90%
99.7%99.8%
0%
20%
40%
60%
80%
100%
ETC WHTC
Con
vers
ion
Effi
cien
cy
NOx THC CO PM
13
Further optimisation potential
• Thermal Management - a heating strategy is expected to be used in future
to further improve cold NOx emissions and particulate filter regeneration.
• System design- Component volumes and integration would be optimised
for a production application.
• System optimisation- including urea dosing and distribution.
• Engine calibration.
14
SCR temperatures for ETC and cold WHTC
0
100
200
300
400
500
600
0 300 600 900 1200 1500 1800
Time [s]
Tem
pera
rture
[°C
]
WHTC ColdStart TestETC Test
Temperature at SCR inlet
EGR valve starts operating after ~570s
on cold start tests
Urea injection for SCR started
operating after ~800s on cold start tests
ETC is ahot start test
The results indicate that there is potential for further improvement of emissions on cold-start cycles through thermal management
15
Effect of cold weighting and soak periodon composite WHTC results
0.0
0.1
0.2
0.3
0.4
0.5
0.6
NOx THC CO/10 PM*100
Em
issi
ons
[g/k
Wh]
5 min hot soak, 10% cold weighting10 min hot soak, 10% cold weighting20 min hot soak, 10% cold weighting20 min hot soak, 14% cold weighting
16
95.0095.5096.0096.5097.0097.5098.0098.5099.0099.50
100.00
WHTC_C WHTC_H ETC ESC WHSC
Filtr
atio
n E
ffici
ency
For
Car
bon
Filtration efficiency for elemental carbon
• Particulate filter efficiency for removal of elemental carbon is > 99%.• Efficiencies for particles and elemental carbon are very similar.
17
PAH emissions essentially eliminatedMDLT MDLT
ETC results Split Ratio Split Ratio
1910 1003
Engine-out Post-cats System ng/µl ng/µl Efficiency
FLUORENE 0.01880 0.00000 100.00PHENANTHRENE 0.28530 0.00170 99.69ANTHRACENE 0.00320 0.00009 98.61FLUORANTHENE 0.19390 0.00040 99.89PYRENE >0.53 0.00050 >99.95BENZ(A)ANTHRACENE 0.00450 0.00030 96.50CHRYSENE 0.01130 0.00020 99.07BENZO(B)FLUORANTHENE 0.01130 0.00010 99.54BENZO(K)FLUORANTHENE 0.00310 0.00006 98.98BENZO(A)PYRENE 0.00300 0.00000 100.00BENZO(GHI)PERYLENE 0.04450 0.00000 100.00INDENO(1,2,3CD)PYRENE 0.01330 0.00010 99.61
18
NOx, PM and particle number comparisons
PM result on ESC appears due to desorption of low volatility materials in Mode 10.
0.0
0.5
1.0
1.5
2.0
ETC WHTC Bus Cycle ESC WHSC
NO
x g/
kWh
0.000
0.005
0.010
0.015
0.020
ETC WHTC Bus Cycle ESC WHSC
PM
g/k
Wh
1.E+10
1.E+11
1.E+12
1.E+13
1.E+14
1.E+15
1.E+16
ETC WHTC Bus cycle ESC WHSC
parti
cles
/kW
h
Engine-out levels
0%
20%
40%
60%
80%
100%
ETC WHTC Bus Cycle ESC WHSC
NO
x co
nver
sion
%
- EEV limit value - - EEV limit value -
19
Summary of findings of the AECC heavy-dutyEuro VI test programme
• A state-of-the-art engine system comprising a low emissions “world engine” and an emissions control system produced substantial reductions in all regulated pollutants.
• NOx conversion efficiencies were 86% and 76% over the ETC and EU-composite WHTC respectively, resulting in tailpipe levels of 150 and 300mg/kWh.
• PM conversion efficiencies were >99.5% over the ETC and EU-composite WHTC, resulting in PM tailpipe levels of 1 to 2mg/kWh when measured with the partial flow method.
• There is potential for further improvement of emissions through thermal management and optimised system design and engine and urea dosing calibration.
20
Summary of findings of the AECC heavy-dutyEuro VI test programme
• The PMP particle number method proved very reliable even at near-ambient particle emissions levels.
• Engine-out particle emissions of 2.5 to 5 x 1014/kWh were reduced to levels below 1012/kWh at tailpipe and were essentially cycle-independent.
• The emissions control system reduced elemental carbon emissions by more than 99% and virtually eliminated PAH emissions.
• The combined engine and emissions control system metthe most stringent scenarios from the Commission’s Euro VI validation exercise.
21
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
0.00 1.00 2.00 3.00 4.00 5.00 6.00
NOx g/kWh
PM
g/k
Wh
2002 2006 2007 (Euro V & EEV data)
Euro III limits
Euro III limits (<0.75dm3 & >3000min-1 rated power speed)
Euro IV limitsEuro V limits
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
0.00 1.00 2.00 3.00 4.00 5.00 6.00
NOx g/kWh
PM
g/k
Wh
2002 2006 2007 (Euro V & EEV data)
Euro III limits
Euro III limits (<0.75dm3 & >3000min-1 rated power speed)
Euro IV limitsEuro V limits
Euro III limits
Euro III limits (<0.75dm3 & >3000min-1 rated power speed)
Euro IV limitsEuro V limits
Euro III limits
Euro III limits (<0.75dm3 & >3000min-1 rated power speed)
Euro IV limitsEuro V limits
PM vs NOx (ESC test)
Source: KBA data, June 2002, January 2006, March 2007AECC Euro VI tailpipe result