Bilteknologi - NOx og helseskadlige avgasutslipp
Oslo 26.9.2011
Nils-Olof Nylund, Juhani Laurikko & Maija Lappi
VTT Technical Research Centre of Finland
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Outline
Environmental challenges and current status of vehicles VTT’s emission test facilities and test methodology
Examples on VTT’s HD research activities
NO/NO2 emissions for various vehicle technologies
passenger cars and HD vehicles
Summary
Community structure
Traffic volumes &
choice of transport mode
Energy for transport
Vehicles and user behaviour
Elements affecting the environmental impacts of traffic
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Current status of vehicles
The current passenger car is:
reliable comfortable relatively safe
environmentally friendly regarding regulated emissions in most cases a ”high-performance” vehicle
What should be improved?
fuel efficiency
the ability to use renewable or CO2-neutral energy rational use of cars
Traditionally heavy-duty vehicles have been fuel efficient but dirty, but with the JPN 2009, US2010 and Euro VI emission regulations the situation will change
Regulated emissions can be reduced significantly - provided that we have high-quality fuels
Source: B. Knight/Honda Motor Company 2004
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Remaining air quality issues – NO2 and particles
Helsinki Region Environmental Services Authority
Lutz 2007
Characterisation of vehicles and fuels
In order to evaluate and improve vehicle technologies and fuels you have to be able to measure exhaust emissions and fuel efficiency
Regulated as well as unregulated emission components Light- and heavy-duty vehicles
Varying ambient conditions
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VTT’s research facilities
VTT has world-class research facilities for vehicle and fuel research
climatic (-30 oC) test chamber for light-duty vehicles
transient test facility for heavy-duty vehicles (up to 60 tons) engine dynamometers
accredited measurement methods for energy use and exhaust emissions sophisticated equipment for measuring unregulated emissions
(a must in fuel research)
In 2002 VTT (Technical Research Centre of Finland) commissioned a new chassis dynamometer emission laboratory for heavy-duty vehicles
VTT has tested close to 500 HD vehicles
buses as well as trucks
vehicles with Euro I to EEV emission certification, diesel and NG
a comprehensive data base on emission factors and fuel consumption has been generated
Types of activities
development of measurement methodology
determination of real-life emission characteristics determination of fuel efficiency
research on fuel savings
research on new biofuels (next generation)
VTT’s activities on HD vehicles
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Heavy-duty vehicle chassis dynamometer facility
The Finnish Centre for Metrology and Accreditation granted accreditation for VTT’s measurements in 2003
Examples on VTT’s HD research activities
Fuel efficiency and exhaust emissions – general Biogas (Baltic Biogas Bus Project)
Paraffinic diesel fuel (HVO, the OPTIBIO project)
IEA Bus Project: Fuel and Technology Options for Buses
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Heavy-duty vehicles
www.transeco.fi
Actual bus performance – 2010 database
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Development of emission limit values
Relative NOx & PM limit values
100
88
63
44
25 25
100
69
44
8 8
6 0
10 20 30 40 50 60 70 80 90 100
Euro I Euro II Euro III Euro IV Euro V EEV
NOx rel.
PM rel.
Limit values vs. true diesel bus performance
True relative NOx & PM performance
83
54
38
14 55
54
46
45
26
20 100
0 10 20 30 40 50 60 70 80 90 100
Euro I Euro II Euro III Euro IV Euro V EEV
NOx act. rel PM act. rel
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Bus NOx and PM emissions
NOx and PM emissions over the Braunschweig city bus -cycle
0 3 6 9 12 15
0.00 0.05 0.10 0.15 0.20 0.25 0.30
PM g/km
NOx g/km
Diesel Euro 2 average Diesel Euro 3 average Diesel Euro 4 Diesel Euro 5 Diesel EEV CNG Euro3 average CNG EEV
Light weight Euro 3 calibration Euro limits (by factor 1.8)
Euro 1
Euro 2
Euro 3 ESC ETC Euro 4
EEV Euro 5
Euro 6 (proposal)
CNG vehicles
Particle number emissions – diesel and CNG
Environmental benefits with biogas buses
Nordic Biogas Conference
Oslo, 10 – 12 March 2010
Nils-Olof Nylund
VTT Technical Research Centre of Finland
Critical emission components
For urban air quality:
particulates
oxides of nitrogen (NOx) and specifically nitrogen dioxide (NO2) new diesel technology: increased share of NO2 in exhaust stoichiometric natural gas: close-to-zero direct NO2
For global warming:
carbon dioxide (CO2) methane (CH4)
Noise:
gas buses emit less noise than diesel buses
Bus Fleet Operation on Renewable Paraffinic Diesel Fuel
Reijo Mäkinen, Helsinki Region Transport Nils-Olof Nylund & Kimmo Erkkilä, VTT
Pirjo Saikkonen, Neste Oil
Arno Amberla, Proventia Emission Control
JSAE20119172 SAE 2011-01-1965
JSAE20119172 SAE 2011-01-1965
The goal of the “OPTIBIO” project was to verify the feasibility of high quality, high concentration “drop-in” biofuels as fuels for urban bus fleets
general functionality and cold-weather performance
compatibility with existing infrastructure and existing vehicles emission benefits
In this case, the fuel was paraffinic renewable diesel fuel made by hydrotreatment of vegetable oils and animal waste fats
(HVO)
The core of the OPTIBIO project was a 3.5 year field test with
some 300 buses
JSAE20119172 SAE 2011-01-1965
Work program
Field test
Engine and vehicle tests in laboratory conditions
Analysis of fuels, lubricants and diesel injection
equipment
JSAE20119172 SAE 2011-01-1965
NOx and PM emissions over the Braunschweig city bus -cycle
0 2 4 6 8 10 12 14
0,00 0,05 0,10 0,15 0,20 0,25 0,30
PM g/km
NOx g/km
Euro II
Euro IV
EEV
Euro III
Average reductions (fuel effect):
•PM -30 %
•NOx -10 %
FUEL AND TECNOLOGY ALTERNATIVES FOR BUSES Overall energy efficiency and emission performance
Update on AMF Annex XXXVII/HEV Annex XVI/Bioenergy Task 41/Project 3
18.8.2011 Nils-Olof Nylund VTT Technical Research Centre of Finland
Bus project objective
To produce data on the overall energy efficiency, emissions and costs, both direct and indirect costs, of various technology options for buses
Provide solid IEA sanctioned data for policy- and decision-makers
Bring together the expertise of various IEA Implementing Agreements:
Bioenergy: fuel production
AFC & Hydrogen: automotive fuel cells AMF: fuel end-use
AMT: light-weight materials
Combustion: new combustion systems HEV: hybrid power-trains
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Contents
Well-to-tank analysis
based on existing data for various fuel options ranges depending on feedstock and process Tank-to-wheel analysis
actual testing of the most relevant technology and fuel options fuel efficiency and exhaust emissions
effects of driving conditions (lessons learned from Annex XXIX) Well-to-wheel analysis
synthesis of WTT and TTW Cost estimates
direct costs (infrastructure, fuel and vehicle) external costs (valuation of exhaust emissions) Reporting on test fleets
when feasible
Well-to-tank
•AMF
•Bioenergy Task 39
•ANL
•NRCan
•VTT
Overall assessment of energy, emissions, externalities and costs
•ADEME
•ANL
•EC
•NRCan
•VTT
AFC Outlook
AMF Outlook
AMT
Outlook HEV Outlook Combustion
Outlook Biofuels
Outlook Hydrogen
Task and cost sharing Task sharing
Tank-to-wheel
•EC
•VTT
•AVL MTC (on-board)
•VTI (engine tests)
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Vehicles measured by VTT
Diesel Volvo EuroII Diesel Scania Euro III Diesel Volvo SCR EEV Diesel Scania EGR EEV
Diesel Solaris/Eaton parallel hybrid Diesel Volvo parallel hybrid
Diesel Golden Dragon hybrid (supercaps, Cummins engine) Diesel Iveco series hybrid
CNG MAN EEV CNG Scania EEV Ethanol Scania EEV
DME Volvo (truck, simulated as a bus)
Full diesel fuel matrix measured with some of the vehicles
Overall energy efficiency and emission performance
AMF Annex XXXVII
May 2011
Environment Canada
Debbie Rosenblatt
Buses Tested at EC (May 2011)
DOC DPF SCR Conventional (A)
EPA 2010
DOC Hybrid (B) DPF
EPA 2007
DOC DPF SCR Conventional (B)
EPA 2010
DOC Hybrid (A) DPF
EPA 2007
DOC Conventional DPF
EPA 2007
DOC Conventional
EPA 1998
Emissions Control Drive
Emissions Certification/
Test Vehicle
~ Euro VI
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PM mutagenicity – TA98
Extracts (left) Condensates (right)
NO/NO2 emissions for various vehicle technologies
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Why NOx as limit value?
Emission Regulations have traditionally set limit values for NOx, i.e. the sum of NO + NO2
Reasoning behind this is based on several facts:
NO is not a stable compound
thus it is not possible to measure NO2 using the standard ”bag-analysis”
method that is the basis for legislative measurements of exhausts
Therefore, it was more practical to set limit value for the sum (NOx), because that is not dependent on the share of each component, which is time-
dependent
even today, because of the ”transient nature” of NO, measuring NO2 must be done using on-line analysis and modal measurement
Why the interest in NO
2?
Many recent exhaust emission after-treatment technologies, especially in diesel-powered vehicles, include very efficient oxidising catalysts that tend to increase the share of direct NO2 amongst NOx emissions
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Europe has switched to diesel
Source: ACEA, Wood McKenzie 2010/Europia
N.B: diesel sum of HD + LD, increase in diesel switch from gasoline to LD diesel + increase in commercial diesel
NO & NO
2in various bus technologies
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NO & NO
2in various bus technologies
Euro aftertreatment # busses NOx(g/km) NO2 (g/km) NO (g/km) NO2 %
EU2 DOC 8 11.2 1.0 10.2 8.7
dPDF 5 11.6 3.0 8.6 25.3
EU3 DOC 9 6.9 0.3 6.6 4.6
EGR 1 8.3 0.2 8.1 2.4
dPDF 3 7.9 3.2 4.8 39.4
EU4 EGR 6 8.1 0.7 7.4 9.1
EU5 SCR 2 9.6 1.3 8.3 11.2
EEV SCR 5 6.4 0.3 6.1 4.3
SCR+pDPF 1 5.3 2.5 2.8 47.3
SCRT 1 6.1 2.3 3.8 37.7
EGR+DOC 6 6.8 2.3 4.5 33.9
EEV CNG-TWC 1 1.8 0.0 1.8 1.7
CNGlean 1 6.0 0.1 5.9 1.9
in total 49
NO & NO
2in various truck technologies
CNG LEAN
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NO & NO
2in selected car technologies (petrol)
NO & NO
2in selected car technologies (petrol)
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NO & NO
2in various car technologies (diesel)
Selected Technologies – G & D
Late-model DPF-equipped diesel cars emit very high direct NO2 –levels Of after-treatment equipped petrol-fuelled technologies the ”stratified-lean”
FSI combustion with ”storage-NOx” –type of catalyst is the most critical for direct NO2
NO2 levels are, however, only some 10 – 20 % of the DPF diesel levels and lower than those of non-cat petrol vehicles
technology MY cycle ambient/start-up NOx (g/km) NO2 (g/km) cold-% ambient/start-up NOx (g/km) NO2 (g/km) warm-%
G FSI, lean-NOx 2003 Helsinki-city +23 C, cold-start 0.27 0.013 5.0 % +23 C, warm start 0.26 0.026 10 %
ECE15 +23 C, warm start 0.138 0.030 22 % +23 C, warm start 0.074 0.029 39 %
D (PD+TC), DOC 2008 Helsinki-city +23 C, cold-start 0.58 0.205 35 % +23 C, warm start 0.60 0.300 50 %
ECE15 +23 C, warm start 0.40 0.144 36 % +23 C, warm start 0.39 0.146 38 %
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Summary
There has been significant progress in vehicle technology over the last 20 years
Regulated emissions have been drastically improved, but:
new diesel buses do not deliver as good real-life emission performance as expected
direct NO2 emissions are increasing mainly due to PM reducing exhaust after- treatment technologies for diesel vehicles
NO2 to NO ratio can be as high as 2:1
For diesel vehicles reducing particulate mass emissions is in conflict with direct NO2 emissions
Summary
When evaluating vehicle performance unregulated emissions should also be taken into account
direct NO2
particle numbers exhaust mutagenicity etc...
In the case of city buses, methane delivers superb performance:
low particulate mass and particle numbers
low NOx and for stoichiometric engines practically zero direct NO2
Who will develop a universal index for exhaust gas harmfulness?
