nstitute for nternal Combustion Engines and Thermodynamics Local and European Scopes to Reduce Emissions from Traffic The challenge of Air Quality: a regional perspective Conference, 10 November 2011 Univ.-Prof. Dr. Stefan Hausberger Dr. Martin Rexeis D.. Raphael Luz Univ.-Prof. Dr. Peter J. Sturm 1
nstitute for nternal Combustion Engines and Thermodynamics CONTENT ntroduction Emissions in type approval and in real world operation PM NOx and NO 2 What can we do, if fleet renewal is not sufficient? (EZ, Retrofit, traffic light coordination, speed limits, n-use tests) Summary and conclusions ntroduction Real World Emissions Measures Summary 2
nstitute for nternal Combustion Engines and Thermodynamics ntroduction The vehicle emissions have been reduced over the last years for most exhaust gas components Tighter air quality limits gave impulses for lowering the exhaust gas limits for vehicles Today still air quality limits for PM and NO 2 are exceeded in several regions presentation deals with NO x and PM The air quality targets for PM and NO 2 and the improvements to be expected from vehicle fleet renewal in the near term seem to leave a rather large gap open. pressure to local measures. NO 2 air quality trends Austria EU limits 2010 ntroduction Real World Emissions Measures Summary 3
nstitute for nternal Combustion Engines and Thermodynamics Background from TU Graz on the topic TU Graz compiles vehicle emission factors (g/km) for the HBEFA V3.1 and for COPERT which are based on emission measurements on 118 HDV and HDE 3000 PC and LCV (~1000 tested also in real world cycles) from measurements at TÜV-Nord, EMPA, TUG, nrets, VTT, TNO, Emission factors are simulated with the Model PHEM from TU Graz. PHEM can be used also to calculate emissions for any local driving situation, as soon as vehicle speed trajectories are available. assessment of effects from speed limits, traffic light control and roundabouts, etc. for several regions in the last years. TU Graz also calculates the Austrian Emission inventory for the transport sector and evaluates effects of measures on national level. TU Graz is consultant of the Commission for several type approval test procedure developments. TU Graz develops engine and drive trains, has air quality monitoring system and simulation tools, etc. ntroduction Real World Emissions Measures Summary 4
nstitute for nternal Combustion Engines and Thermodynamics Diesel Engines as Source for PM Emissions PM emissions from passenger cars -40% -80% -95% 0,001g/km + DOC +DPF mproved combustion ntroduction Real World Emissions Measures Summary 5
nstitute for nternal Combustion Engines and Thermodynamics Efficiency from Particle Reduction mproved combustion for higher fuel efficiency typically also reduces PM Particle filter is similarly efficient at any engine load. Removal by mpaction and Diffusion Efficient in all particle size classes Removal efficiency [%] Small particles measured after the filter are typically condensed gas droplets. Health effect compared to conventional PM with soot core? ntroduction Real World Emissions Measures Summary 6
nstitute for nternal Combustion Engines and Thermodynamics Non Exhaust as Source for PM emissions Sources are tire- and brake wear and dispersion Data base for non exhaust PM emission factors is rather poor Non Exhaust ~ 50 x Exhaust for EURO 5 ntroduction Real World Emissions Measures Summary 7
nstitute for nternal Combustion Engines and Thermodynamics PM Exhaust reduced, non exhaust remains topic Example: PM emissions from transportation in the Austrian nventory (only road) Population diesel cars +3 000% ntroduction Real World Emissions Measures Summary 8
nstitute for nternal Combustion Engines and Thermodynamics 8.0 7 7.0 Diesel engines as NO x source Emission limits for Diesel NOx PKW NOx SNF g/kwh 6.0 5.0 4.0 3.0 2.0 4.1 3.5 5 1.7 3.5 1.2 2 HDE-Test: ECE R49 ESC ESC+ETC WHTC 1.0 0.6 0.46 0.0 EU2 EU3 EU4 EU5 EU6 1996 2000 2005 2008 2014-60% -40% to -80% -50 to -80% ECUs ECU mproved Combustion + NOx-Exhaust gas after treatment (HDV from EURO V on) +Optimisation of the systems ntroduction Real World Emissions Measures Summary 0g/km? 9
nstitute for nternal Combustion Engines and Thermodynamics NO x from Diesel engines in real world operation NO 2 NO 2 NO 2 NO NO NO Only 2 EU 6 premium cars measured yet! Not representative for EU 6 fleet! ntroduction Real World Emissions Measures Summary 10
nstitute for nternal Combustion Engines and Thermodynamics Real World Emissions from HDV Example: Semitrailer, 40t max. gross vehicle weight, 50% loaded 25 emission factor [g/km] 20 15 10 NO x Euro Euro V - EGR Euro V - SCR Euro V - EGR (prog.) Euro V - SCR Euro V (prog.) Diesel PC EU4 5 0 0 10 20 30 40 50 60 70 80 90 100 average cycle speed [km/h] ntroduction Real World Emissions Measures Summary 11
nstitute for nternal Combustion Engines and Thermodynamics Shares of NO 2 for HDV Euro and older 7% Euro V / EGR 21% Euro V / SCR 7% ncl. PM-Cat Euro V / EGR 21% Euro V / SCR 7% Euro V prognosis 28% 0% 5% 10% 15% 20% 25% 30% NO2 / NOx ntroduction Real World Emissions Measures Summary 12
nstitute for nternal Combustion Engines and Thermodynamics Not perfect type approval test procedures 140 NEDC 120 Real World 100 km/h 80 60 40 20 0 1 101 201 301 401 501 601 701 801 901 1001 1101 Time [s] CADC (Common ARTEMS Driving Cycle) ntroduction Real World Emissions Measures Summary 13
nstitute for nternal Combustion Engines and Thermodynamics Normalized engine power (1 = rated power) 1 0.8 0.6 0.4 0.2 0-0.2 Not perfect type approval test procedures CADC urban CADC road CADC Motorway NEDC Relevant in real world driving but not covered in type approval 77kW rated power mid class car -0.4 0 0.2 0.4 0.6 0.8 Normalised engine speed (0=idling, 1 = rated speed) + different in dynamics, temperatures, etc.: difficult to create perfect test ntroduction Real World Emissions Measures Summary 14
nstitute for nternal Combustion Engines and Thermodynamics Effects of type approval test procedures Optimised combustion for high fuel efficiency results in high NO x engine out emissions. High NO x conversion from SCR catalyst + high engine-out NO x emissions results in high Ad-Blue consumption. Trade off between vehicle operation costs and low NOx Passenger cars and LCV: NEDC drives at low load and low dynamics only many real world engine loads are not covered Higher NOx in most real world driving conditions than in NEDC mproved test procedure (WLTP) not finalised yet HDV: ETC and ESC do not cover low load very well Higher NOx in real world than in ETC in slow city driving EURO 6 will be tested in new test procedure (WHTC), situation improved ntroduction Real World Emissions Measures Summary 15
nstitute for nternal Combustion Engines and Thermodynamics Options to reduce NO x and NO 2 emissions () ncentives for early introduction of EURO 6 (check real world emissions of EURO 6 concepts in front) Limited effect until 2015 due to limited fleet renewal additional incentives (scrapping bonus, environmental zones,..) can increase the substitution of old vehicles Could increase share of gasoline vehicles (negative CO 2 effect) Could increase share of CNG vehicles (similar CO 2 /km as diesel, pollutants as gasoline cars and LCV) ntroduction Real World Emissions Measures Summary 16
nstitute for nternal Combustion Engines and Thermodynamics Environmental Zones High emitting vehicles have restricted access to cities. Main effect is stimulation of fleet renewal. Effect on PM-exhaust depends which EURO-classes are restricted. EURO 3 and older (as shown below) gives remarkable reductions. PM-Non exhaust nearly not affected. Effect for NO 2 rather small, since EURO 5 diesel cars do not have much lower NO x than EURO 3 Change against BAU [%] 5% 0% -5% -10% -15% -20% -25% -30% -35% -40% -15% -4% -5% 1% within EZ total Graz PM exhaust PM10 traffic NOx NO2 direct ntroduction Real World Emissions Measures Summary 17
nstitute for nternal Combustion Engines and Thermodynamics Optimisation of traffic light coordination nteraction of traffic lights, traffic, drivers, vehicles and engine technology is very complex. Models can help the experts to better understand the emission relevant effects of measures Potential for optimisation for PM, NOx and CO 2 reduction is quite likely in many networks (if not already optimised for emissions) Simulation traffic flow model Emissions from PHEM optimisation loops Result for a section in Graz 0% CO2 NOx PM HC Change to actual control -2% -4% -6% -8% -10% -12% -14% -16% -8% -10% -14% -15% ntroduction Real World Emissions Measures Summary 18
nstitute for nternal Combustion Engines and Thermodynamics Retrofit SCR-catalysts Retrofit systems for HDV reach >80% NOx reduction in the type approval cycle (ETC). ETC is high load cycle with full load pre-conditioning. Exhaust gas temperatures in real world city driving are much lower SCR efficiency drops (-0% to -50% depending on quality of the system) Retrofit SCR-systems shall be tested also on the vehicle in low load city cycles! ETC result is meaningless! SCR-retrofit for cars seem to be much to expensive, for some LCV it could be an option. NOx reduction from SCR [%] 80% 70% 60% 50% 40% 30% 20% 10% 71% NOx reduction t-exhaust upstream SCR 36% 28% 350 300 250 200 150 100 50 Temperature [ C] 0% 0 Engine tested in ETC GVB bus line 1 GVB bus line 2 ntroduction Real World Emissions Measures Summary 19
nstitute for nternal Combustion Engines and Thermodynamics n-use Tests Modern HDV have a very efficient NO x after treatment system (SCR) or internal technology (EGR). Users can tamper these systems (e.g. disconnect EGR or use water instead of AdBlue), what leads to heavily increased NO x emission levels. Most malfunctions are detected by modern vehicles and are indicated by the OBD system. With proper instrumentation tampering and driving with relevant malfunctions could be monitored during vehicle inspections. For single vehicles this would result in NO x reductions up to 70%. How many vehicles are driven with malfunctions and tampering is unknown yet. ntroduction Real World Emissions Measures Summary 20
nstitute for nternal Combustion Engines and Thermodynamics Speed Limits Very efficient for highways to reduce NO x and CO 2 emissions. n urban areas not much potential (e.g. effect of 30 km/h limit depends on % of vehicles driven in 2nd or 3rd gear, driver behaviour, engine technology no general statement on local trends possible) Other commonly discussed measures not discussed here ntroduction Real World Emissions Measures Summary 21
nstitute for nternal Combustion Engines and Thermodynamics Summary and conclusions NO x emission from diesel passenger cars did not drop in real world driving a lot since EURO 0 (CO 2, PM, HC, CO did). Oxidation catalysts and Particle filters increased share of NO 2 on NO x from <10% before EURO2 to >40% for EURO 4 NO 2 air quality effects Specific NO x emissions from actual diesel cars are 10 x higher than from gasoline cars PM exhaust emissions drop significantly from LDV and HDV, share of PM-Non Exhaust increases EURO 6 passenger cars will have low PM but not necessarily low NOx NOx from EURO V HDV did not drop much in low load cycles. For EURO 6 HDV a better behavior is expected due to new test procedure Fleet renewal (gasoline, CNG, EURO 6 diesel) will reduce emissions The potential of alternative measures to reduce NO 2 until 2015 is limited ntroduction Real World Emissions Measures Summary 22
nstitute for nternal Combustion Engines and Thermodynamics Thank you for your attention! Rollenprüfstand für Schwere Nutzfahrzeuge der TU-Graz 23
nstitute for nternal Combustion Engines and Thermodynamics Wie sieht die Zukunft aus? Einflüsse auf NO x and NO 2 von Dieselfahrzeugen AGR: NO x Abnahme, %NO 2 Anstieg ECUs Oxi-Kat + DPF: % NO 2 kann zunehmen (je nach Ausführung und Abgas) Rußabbrand: C + O 2 CO 2 >500 C C + 2NO 2 CO 2 +2NO >300 C Hoher NO 2 -Anteil erwünscht kein NO 2 erwünscht SCR: NO x Abnahme, % NO 2 Abnahme NO x -Speicherkat: NO x Abnahme Schnelle SCR-Reaktion: NO + NO 2 + 2 NH 3 2 N 2 + 3 H 2 O ca. 50% NO 2 vor SCR erwünscht Einleitung Simulation am VT Emissionen Luftgüte Maßnahmen 24
nstitute for nternal Combustion Engines and Thermodynamics Motorbelastung im NEDC und CADC Normalized engine power (1 = rated power) 1 0.8 0.6 0.4 0.2 0-0.2 CADC urban CADC road CADC Motorway NEDC Relevanter aber nicht erfasster Kennfeldbereich 77kW Nennleistung Golf Klasse -0.4 0 0.2 0.4 0.6 0.8 Normalised engine speed (0=idling, 1 = rated speed) Einleitung Daten Real World EURO 6 Temperaturprobleme Zusammenfassung 25