EMIS hearing of 28 April Questions to the Institute for Energy and Environmental Research, Heidelberg

Transcription

1 Committee of Inquiry into Emission Measurements in the Automotive Sector A EMIS hearing of 28 April 2016 s to the Institute for Energy and Environmental Research, Heidelberg Preliminary note: ifeu s main field of expertise in relation to EMIS lies in the modeling of road transport emissions, the analysis of the impact of transport on air pollution as well as the assessment of the future development of road transport emissions and the related ambient air quality situation. Therefore the focus of the following answers is on question 12. The other questions have been dealt with more briefly with references to other experts. 1

2 12A What is the contribution of NO 2 from road transport, and in particular from diesel passenger vehicles, on air quality and the impact on permitted NO2 concentrations levels as defined by EU air quality legislation? The contribution of motor vehicles to local NO 2 concentrations varies between air quality measurement stations. NO x emissions of vehicles contribute directly (NO 2 ) and via atmospheric chemical reaction (NO) to ambient air pollution. The level of NO and NO 2 emissions from traffic depends mainly on the local traffic volume, traffic situation and fleet composition (e.g. share of different Euro stages). At traffic measurement sites in Germany, local road traffic and the traffic related background concentration mostly contribute over 50 % to the ambient air NO 2 concentration, at some sites even significantly more. ( Main source of the traffic related NO 2 immission load are diesel passenger cars by continuing high NOx emissions as well as high share directly emitted NO2. An ifeu study for the city of Munich showed that % of the local NO2 contribution at the measurement site in 2010 was due to diesel passenger cars. The contribution of diesel cars probably even increased between 2010 and 2015 because also Euro 5 did not lead to a reduction in real world emissions. NOx emissions of gasoline cars and trucks, on the other hand, have further decreased. 12b What is the tendency observed for the reduction of nitrogen oxides, and NO2 in particular? To what extent, and to which level of confidence, are high NO2 levels measured in cities attributable to emissions from road transport, and in particular from diesel vehicles? The development of the measured NOx concentration (sum of NO and NO2) shows a stagnation or only slight decrease in recent years at the sites analyzed by ifeu. At many highly polluted sites in Europe also NO2 concentrations have hardly decreased in the past years. Air quality monitoring of the European Environment Agency (EEA) shows that NO2 air quality standards are mostly exceeded at traffic related measurement sites (e.g. at % of the traffic sites in Germany, France and Italy), but only sporadic at sites without relation to traffic ( (see also Annex 1) Reasons for the absence of air quality improvements are the continuing high NOx emissions from diesel cars along with the further increased share of NO2 and total NOx emissions as well as the general increase in diesel car mileage. The aforementioned ifeu analyses (12a) have shown that the 2

3 main contributor to the NO2 concentration is local traffic dominated by the diesel car. The contribution of local diesel cars to the NO2 concentration at all analyzed Munich measurement sites was above one third (Annex 2). Additionally diesel cars contribute to the background concentration. Also analyses of other institutes come to similar conclusions and confirm the dominant role of diesel cars for ongoing high NO2 concentration at many sites in Europe. In the recent analyses of IIASA for the Revision of the Thematic Strategy on Air Pollution for all European traffic measurement stations on average 40 % of the NO2 concentration are attributed to diesel cars and light duty vehicles, 75 % to overall road traffic. 12c Would you have expected the introduction of the Euro 5 and Euro 6 standards for passenger cars to cause a noticeable reduction of direct NO2 emissions and by how much (estimation)? What was the result instead? Analyses of ifeu from 2007 showed that the increase in direct NO2 emissions (e.g. due to an oxidation catalytic converter - Oxi-Cat) of diesel vehicles have a relevant influence on the level of NO2 pollutant concentrations. The results of this analysis have been discussed with the automotive industry and other stakeholders in order to raise awareness and initiate the development of reduction strategies. Several suggestions, e.g for alternative coatings of exhaust after treatment systems, have been discussed. Expectations were targeted toward a reduction of NO2 emissions. It has to be noted that NO2 emissions differ largely by engine operation conditions, exhaust gas reduction technologies and other factors. No analyses of NO2 emissions of Euro 5 and Euro 6 vehicles have so far been conducted by ifeu. Current emission factor databases (HBEFA 3.2) assume a decreasing share of NO2 on total NOx emissions from Euro 5 /Euro 6 diesel passenger cars compared to Euro4 diesel cars. Whether NO2 emissions decrease in specific traffic situations thus strongly depends on the reduction of total NOx. In this respect further analyses of current data (laboratory, PEMs, remote sensing) are necessary in order to come to a valid conclusion. 3

4 12d How much of the NO2 limit value exceedances can be estimated to be due to the gap between emissions measured during type-approval testing and in real world conditions? Several reasons for the non-compliance with NO2 air quality standards at traffic related measurement sites in Europe can be identified: 1) The share of diesel vehicles on passenger car new registrations was low in most European countries in 1999, but has increased considerably (e.g. in Germany from 22 % in 1999 to currently almost 50 %). Since considerably higher NOx limit values apply for diesel cars in comparison with gasoline cars, the diesel boom is one important reason for the limited reduction in NO2 concentrations. 2) Exhaust emission standards for diesel cars have not led to a decrease in NOx emissions as expected. This absence of real world emission reductions correspondingly has reinforced the effect of the diesel boom on NOx and NO2 concentrations. 3) The emission legislation regulates the sum of nitrogen oxides (NO x ). Since Euro 3, however, the share of directly emitted NO2 in diesel car exhaust has increased considerably. These NO2 emissions directly contribute to the NO 2 concentration, while NO emissions only partly are conversed to NO2 concentrations. The effect of increased real world emission (see 2) of diesel cars and light duty vehicles on NO2 concentrations have been assessed by IIASA. Accordingly about two thirds of the current exceedances of air quality limit values could have been avoided if NOx emissions of diesel vehicles would not have been increased compared to the limit values. Source: Current analyses of IIASA as part of the Revision of the EU Thematic strategy on Air Pollution. 4

5 1 Please list the available technologies for mitigation of NOx emissions and their respective advantages, disadvantages and costs. Taking into account the latest technological developments, under which ambient conditions do they work? How do ambient temperatures affect emission control technologies? What is the range of temperatures in which these technologies are technically operable, and why? Would it be possible to have emission control systems that work well in the full range of temperatures experienced in Europe? In passenger car diesel engines exhaust gas recirculation (EGR), variable compression ratio (VCR) and homogeneous charge compression ignition (HCCI) are used as internal technologies. Lean-burn NOx adsorbers (NOx traps, LNT) and selectiv catalytic reduction (SCR systems) are common after treatment systems to reduce NOx emissions of passenger cars to the Euro 6 level. The different technologies/strategies have specific advantages and disadvantages. A combination of technologies allows for emission reductions in a broad temperature range if an intelligent operation strategy and system design is applied (e.g. combination of LNT and SCR). For detailed answers on technology and costs it is referred to other organisations (e.g. ICCT, ADAC, JRC, AECC). Answers of these institutes can be found e,g, in the other hearings (e.g. JRC, ICCT on April 19 th, 2016). Current literature on the topic: ICCT: NOX control technologies for Euro 6 Diesel passenger cars; Market penetration and experimental performance assessment; e.g. Table 1. 5

6 2 Is it technically possible to reduce fuel consumption (and hence CO2 emissions) and NOx emissions at the same time or, given the physical nature of combustion, focusing on reducing consumption entails higher NOx emissions and vice-versa? What would be the best technical solution to reconcile these goals? Is it possible for car manufacturers to comply with CO2 limits for the fleet average and respect NOx thresholds with current diesel technology? If NOx reduction is achieved with a highly effective after treatment system (e.g. SCR), in principle more flexibility arises for engine optimization. In contrast to a reduction without NOx after treatment, the engine could then be optimized towards fuel efficiency. Further information can be acquired from more technology focused institutes/organizations, e.g. FEV, JRC, AECC, Technical University Graz,.. Additionally other measures (e.g. weight and air drag reduction, improvements of the drive train, hybridisation) can be used to reduce the energy consumption of the vehicle apart from improvements of the engine. 3 The NOx emission control techniques available at the time of adoption of the Euro5/6 legislation, and the ones that have shown best results in tests, are exhaust gas recirculation (EGR), lean NOx trap (LNT) and selective catalytic reduction - AdBlue (SCR). Is it technically possible to meet NOx emission limits of 80 mg/km in normal driving conditions with a combination of these technologies? If so, since when has it been possible? Is it possible without using all three at the same time? Would it be possible to meet more stringent limits, with which technologies and at what additional cost? Recently published measurements show, that it is in principle possible to meet Euro 6 limits over a broad range of traffic situations (including also RDE). It is expected that a combination of technologies (EGR, LNT, SCR) is needed to reduce NOx emissions over a wider range of driving situations. Further information could be acquired from more technology focused organizations 6

7 4 Have there been any recent developments in NOx emission reduction techniques? For instance, in order to contribute to closing the gap between emission measured during type-approval tests and real world emissions, do catalyst systems need better calibration, or to advance their technical development? See also preceding question. System design and control have a great impact on the achievable reduction in real world driving. A reduction of real world emissions to 80 mg/km is technically already possible, as is demonstrated by current measurements. Further informations could be acquired from more technology focused organisations (e.g. FEV, LAT, ADAC, JRC, AECC) 5 Would after-treatment systems effective for NOx abatement substantially increase the fuel consumption of vehicles and result in high production costs, in particular in the case of small engines, as claimed by some manufacturers? Would they influence engine performance, and how? Could more efficient emission control technology used in large engines be used in small engines? See answer to question 2 From an environmental point of view, all passenger cars should have to meet the same NOx emission limits, regardless of the drive train concept. This could require a higher technical and financial effort to meet the limits also for small diesel cars. This could lead to a shift of potential buyers of such vehicles to other drive train concepts which might have higher CO2 emissions. Such a potential effect should (hopefully) be limited by a tightening of CO2 fleet targets in the future. 7

8 6 Are all NOx abatement techniques vulnerable to manipulation by software defeat devices, and why? What is the reason why NOx control techniques are not operated in full, at all speeds and ambient temperatures? What is the reason why reduction technologies are active and effective during type approval tests, but can be partly switched off during real world operation? Possibilities of a manipulation have been discussed by ICCT ( ): NOX control systems are active, meaning that they must be intelligently managed by software in the vehicle s electronic control unit based on a series of input parameters. But managing those NOX control systems in such a way as to circumvent a vehicle emissions test is functionally no different than managing them in order to minimise NOX emissions at all conditions. So, for example, the software routine that regulates the injection of urea in a selective catalytic reduction system could reduce the frequency under certain conditions (i.e., off the test cycle) in order to conserve urea, which would reduce the frequency with which an owner would need to have the vehicle serviced. The software routine that enriches the airto-fuel ratio in order to regenerate a lean NOX trap could be made to do so less frequently in order to obtain better fuel economy or permit the use of a less durable catalyst. And the routine that controls exhaust gas recirculation can vary the percentage of EGR to optimise NOX control or to improve fuel economy and power. 7 Regulation 715/2007 prohibits the use of defeat devices, but there are derogations that permit the use of defeat devices under certain conditions such as protection of the engine against damage or accident and for safe operation of the vehicle. How can reduced effectiveness or the complete deactivation of emission control systems prevent accidents or engine damage? What kind of everyday situations would make it necessary to deactivate or reduce the effectiveness of emission control systems, and how likely are those situations? From an environmental point of view, the regulation should aim to achieve a real world effect. Exceptional rules should be restricted to exceptional situations and circumstances. Primarily the regulation need to lead to an effective improvement of real world ambient air quality and not only demonstrate bench test value improvements. This point of view focusses on the environmental side and does not take into account a legal point of view. For further information on the necessity of turning-off emission control systems in certain conditions (e.g. due to urea deposits) technical organisations need to be contacted. 8

9 8 How reliable are portable emissions measurement systems (PEMS)? What technical limitations do PEMS have on the road? Do you think the accuracy of PEMS within the next five years would be sufficient to evaluate on-road emission precisely? Would research on PEMS need additional funding to ensure the development of viable and reliable measurement systems? ifeu is not particularly involved in this question. Detailed answers on technology and costs could be given by other organizations, e.g. ADAC, TÜV, Technical University Graz. 9 What is your opinion of the current and future state of the diesel vehicle technology? Has the diesel engine reached its technical potential, or can it improve in terms of fuel efficiency and emissions, and how? Would future improvements rather come from the combustion technology itself (such as advance combustion modes or Exhaust Gas Recirculation), from after-treatment such as SCR, or from working on the diesel fuel itself? Would retrofitting certain diesel-engine passenger cars with additional emission-mitigation technology be viable, and what would be the cost? ifeu is not particularly involved in this question. Detailed answers on technology and costs can be given by other organisations 10 Which regulatory changes and/or technical tools would allow us to reduce air pollutant and greenhouse gas emissions from vehicles, and ensure that legal requirements are met not only during type-approval testing but also throughout the full life cycle of vehicles across a wide range of operating conditions? Which policy responses would be the most effective to deal with defeat devices and to improve current compliance and enforcement? Realistic test procedures (in respect to driving cycle, air conditioning), ban of defeat devices, strict monitoring PEMS and RDE appear to be good approaches for a reduction of real world emissions. Potential loopholes need to be analyzed and avoided Extension of in-use testing (e.g. with PEMs, field monitoring) Discussion of further field monitoring (e.g. by remote sensing) in order to detect and analyze statistically relevant discrepancies between real world emissions and legal limit values. Withdrawal of type approval in case of legal violations 9

10 11 Which capabilities does your Institute have with regards to the functioning and analysis of Emission Control Units (ECUs)? What is the current state about academic research in programming and designing ECUs? Can you list any contractual obligations such as non-disclosure agreements, grant agreements, non-compete clauses in work contracts the IFEU has or individual employees at the IFEU have that prevent, restrict or otherwise influence their ability to conduct research of or publish about ECUs and its components? ifeu is not particularly involved in this question. 13 What are the impacts of NOx emissions on the environment and on health? In particular, can you estimate the impact on health of the NOx emission exceedances in the EU since the introduction of Euro5/Euro6 standards? EEA gives an overview: NO X contributes to acid deposition and eutrophication which, in turn, can lead to potential changes occurring in soil and water quality. The subsequent impacts of acid deposition can be significant, including adverse effects on aquatic ecosystems in rivers and lakes and damage to forests, crops and other vegetation. Eutrophication can lead to severe reductions in water quality with subsequent impacts including decreased biodiversity, changes in species composition and dominance, and toxicity effects. In many cases, the deposition of acidifying and eutrophying substances still exceeds the critical loads of the ecosystems (see EEA indicator Core Set Indicator (CSI) 005 'Exposure of ecosystems to acidification, eutrophication and ozone'). Further details concerning emissions of acidifying pollutants are provided in EEA CSI 001 'Emissions of acidifying substances. It is NO 2 that is associated with adverse affects on human health, as at high concentrations it can cause inflammation of the airways. NO 2 also contributes to the formation of secondary particulate aerosols and tropospheric ozone (O 3 ) in the atmosphere - both are important air pollutants due to their adverse impacts on human health. NO x is therefore linked both directly and indirectly to effects on human health. Further details concerning the contribution of NO X to emissions of tropospheric ozone precursors and particulate matter are contained in EEA CSI 002 'Emissions of ozone precursors' and CSI 003 'Emissions of primary particles and secondary particulate precursors'. ifeu has not carried out an analysis about the impact of NOx emission exceedances in the EU. 10

11 Annex 1: Source EEA 2014 Fig 1:Development of NO2 annual mean values at traffic measurement sites in selected regions; Source: Von der Emission zur Immission Ursachen hoher NO2-Luftbelastungen in Städten. F. Dünnebeil, presentation in conference Motorische Stickoxidbildung - Nachhaltige Mobilität in Städten und im Fernverkehr, Heidelberg, January 27th

12 Annex 2 Fig 2: Contribution of cars (Diesel-Pkw, Otto-Pkw), LCV (LNF), HDV (Lkw) and Busses to the ambient NO2 concentration; Source: Von der Emission zur Immission Ursachen hoher NO2-Luftbelastungen in Städten. F. Dünnebeil, presentation in conference Motorische Stickoxidbildung - Nachhaltige Mobilität in Städten und im Fernverkehr, Heidelberg, January 27th