ENTERPRISE AND INDUSTRY DIRECTORATE-GENERAL
Industrial Innovation and Mobility Industries
Automotive industry
Brussels, 01 September 2011
ENTR.F1/KS D(2011)
OBD experts workshop:
Final Euro 6 OBD threshold limits (OTLs)
1.Facts
The following note on Euro 6 OTLs together with a "compromise" regulatory proposal on Euro 6 OTLs has been distributed to TCMV of 19 May:
" The Commission services have issued a study for assessing the final Euro 6 OTLs based on the COM suggestion outlined in the Communication 2008/C 182/08 of 19 July 2008 and the technical feasibility with reasonable costs. The results of this study are expected to become available in the second semester of 2012 and should lead to an immediate Commission service proposal in this respect.
However, during the last few weeks the Commission services have received a proposal from a Member State for Euro 6 OTLs with a view to vote at TCMV in July or September 2011, which comprises the following elements:
- Introduction of two stages of Euro 6 OTLs, which correspond roughly to the values outlined in the COM communication 2008/C 182/08 for a final stage and to values proposed by the Member State (supposingly with some industry support) for an "early Euro 6 phase"
- A revision clause for the final Euro 6 OTL along the lines agreed for PM-OTLs of Euro VI (i.e. in case of demonstrated technical non-feasibility the COM will propose alternatives)
- A quick (positive) vote at TCMV (in July or September), which would allow for Euro 6 type approvals soon, without completing the COM Euro 6 OTL study beforehand.
Notwithstanding the necessary inter-service consultation the responsible Commission services assume that the principles of the Member State proposal could be supported by the Commission, if it would lead to a quick adoption in such a way that Euro 6 type approvals would be possible by the end of 2011 or early 2012. Obviously this requires a clear support by a majority of Member States. In such case the ongoing Euro 6 OTL study would be "converted" into a technical assessment of final Euro 6 OTLs with a somewhat longer timeframe.
It should however be noted that the Commission services do not want to enter into a lengthy technical debate about Euro 6 OTLs at MVEG in parallel to the ongoing study. If therefore the principles of the Member State proposal can not be agreed by a majority at TCMV, the Euro 6 OTL study would have to be finalised before a robust COM proposal can be made."
Since then the "compromise proposal" mentioned in the note has been discussed several times at MVEG and TCMV and just before the TCMV of 17 June a counter proposal from ACEA has been received. Both proposals suggest a two step approach applying "preliminary Euro 6 OTLs" as from the mandatory Euro 6 dates and "final Euro 6 OTLs" two years later and a revision clause for the final Euro 6 OTLs.
The table below tries to analyse various elements, which differ in the two proposals, in a comparative manner in order to allow for an OBD expert discussion focused on the individual points[1]:
Element / "Compromise" proposal of 19 May 2011 / ACEA proposal of 17 June(1) / Preliminary NOx OTL: CI / 180 mg/km / 210 mg/km
(2) / Preliminary PM OTL: CI / 20 mg/km / 30 mg/km
(3) / Revision clause of final OTLs / If technical feasibility is not demonstrated, COM should propose new OTL values and/or implementation dates. / COM shall conduct a review of technical feasibility and costs of OTLslower than those defined now. Implementation of lower OTL values only if technical feasibility and cost-effectiveness is demonstrated with a lead time of 4 years.
(4) / Final CO OTL: PI, CI / 1500, 750 mg/km / 1900, 1750 mg/km
(5) / Final NMHC OTL: PI, CI / 100, 140 mg/km / 170, 290 mg/km
(6) / Final NOx OTL: PI, CI / 90, 140 mg/km / 150, 180 mg/km
(7) / Final PM OTL / 9 mg/km / 15 mg/km
2.Analysis
The position of the Commission on Euro 6 OTLs is expressed in the Commission Communication (2008/C 182/08) of 19.7.2008. In principle the reasons for this position remain valid and any regulatory proposal deviating from this approach will be subject to inter-service discussions, in particular with DG ENV and MOVE.
The following analysis therefore should be understood as a view of the automotive industries Commission service on possible ways forward, balancing the need of getting a robust Euro 6 OBD regulation on the one hand and industry positions on the other hand.
(1)The preliminary NOx OTL proposed by ACEA (applicable only from 1 September 2014) would exceed the NOx threshold of 180 mg/km to be monitored for activating the driver warning/inducement systems of Euro 6- vehicles (applicable now!) according to section 6.2 of Annex XVI to Regulation 692/2008/EC. The latter was introduced on 17 November 2010 upon the explicit request of vehicle manufacturers and would correspond to the preliminary NOx OTL suggested in the "compromise" proposal.
It should also be noted that the NOx monitoring threshold for activating the driver warning/inducement systems has to be done with a relatively high frequency to fulfil the conditions described in sections 4.2, 5.4, 5.5 of Annex XVI to Regulation 692/2008/EC, which is not the case for the NOx OTL (IUPR requirements are expected to lead to a less frequent monitoring). Therefore it is not comprehensible why the technically less demanding NOx OTL monitoring should be done against a higher threshold.
Given the serious NOx air quality problems in most Member States, any further deviation from the NOx OTLs suggested in the Commission Communication than the one already expressed in the "compromise" proposal appears to be very difficult.
(2)It is the intention of the Commission to ensure a robust monitoring of the DPF for partial failures. The engine-out PM emissions of many Euro 6 vehicles are expected to be around or below 20 mg/km, the preliminary PM OTL of 30 mg/km would therefore not deliver the objective. It would not encourage the development of technologies (soot sensors, improved differential backpressure methods) suitable for the monitoring of partial DPF failures.
(3)It should be noted that the revision clause in the "compromise" proposal would potentially lead to less stringent OTLs in the future than the "Euro 6 final OTLs" to be fixed in legislation now, while the revision clause in the ACEA proposal would potentially lead to more stringent OTLs. The numeric values of the "Euro 6 final OTLs" of the two proposals are therefore not directly comparable.
In principle the ACEA proposal of a revision towards possibly more stringent final OTLs (with an initial set of "final" OTLs as a basis) could be followed. It should however be noted that the wording of the revision clause proposed by ACEA and in particular the binding requirement of a 4 years lead time would not be accepted legally, since it would interfere with the constitutional right of initiative of the Commission. Therefore a wording of the revision clause like the following is proposed:
"The Commission shall conduct a review of the technical feasibility and cost effectiveness of OTLs lower than those specified in the table of section 2.3.3[2] ('final Euro 6 OBD threshold limits'). For any proposal amending these OTLs, technical feasibility and cost effectiveness have to be considered and appropriate lead time has to be granted to industry."
(4)and (5): it is the intention of the Commission to monitor the DOC of "final" Euro 6 vehicles also for partial failure, corresponding to global harmonisation with US requirements. The ACEA proposal would present only minor improvements with respect to the Euro 5 OTLs for CO and NMHC. In particular it would monitor the DOC only for total failure, i.e. the objective of global harmonisation would not be achieved.
(6)The final NOx OTLs suggested by ACEA are significantly above the values of the "compromise" proposal and theCommission Communication (2008/C 182/08). They would fail to achieve global harmonisation with the US.
Given the serious NOx air quality problems in most Member States, any further deviation from the NOx OTLs suggested in the Commission Communication than the one already expressed in the "compromise" proposal appears to be very difficult and will not be accepted by DG ENV.
(7)The final PM OTL suggested by ACEA is somewhat higher than the value suggested by the "compromise" proposal and in Commission Communication (2008/C 182/08). It would however probably ensure some monitoring of partial DPF failures. Assuming a revision clause as suggested by ACEA and lined out under point (3), an increase of the "final" Euro 6 PM-OTL of 9 mg/km appears to be feasible.
1
Annex:
Provisions on Euro 6OBD of Commission Communication (2008/C 182/08) of 19.7.2008
…
(16)The implementing legislation does not contain any OBD thresholds for Euro 6 vehicles, apart from interim thresholds designed for the early introduction of Euro 6 diesel vehicles. The full Euro 6 thresholds will need to be confirmed by the Commission before such vehicles are able to be type approved.
(17)An initial proposal by the Commission for Euro 6 OBD thresholds is contained in Table 1. This table shows the thresholds that the Commission considers should be introduced for Euro 6 vehicles.
(18)These OBD thresholds broadly reflect the thresholds applied to most light duty vehicles in the United States and Canada, where the majority of vehicle's OBD systems are compliant with the legislation set by the Californian Air Resources Board (CARB). CARB set thresholds as a multiplication factor of the emission limit value, applying factors of either 1.5 or 1.75. The figures in Table 1 have been derived on this basis, however a higher factor 2 has been applied to particulate limits, reflecting the low concentrations in the exhaust emissions. CARB is currently allowing relaxed OBD thresholds for diesel cars up until the end of 2012. The Euro 6 thresholds would come into effect about 2 years later than this.
(19)Industry has submitted proposals for OBD thresholds at the Euro 6 stage that exceed the limit values by factors ranging from 1.9 to 5.5 for petrol vehicles and from 2.6 to 5.5 for diesel vehicles.
(20)The Commission considers that by the Euro 6 stage of emission limits, there is little reason for European OBD requirements to be significantly different from the requirements in North America. In particular, the diagnostic principles for petrol cars are well understood, having been developed in the US, so could be easily introduced in the EU. Moreover, the work by a consultant reviewing OBD thresholds suggested that the environmental benefits and cost effectiveness of lower petrol OBD thresholds were good.
(21)The Commission is aware that the thresholds for diesel vehicles are technology forcing, particularly with regard to particulates. Such thresholds are considered necessary due to the desirability of detecting partial failures of aftertreatment devices such as particulate filters, which could be subject to tampering if blocked. Moreover, good diesel diagnostics are essential for the long term competitiveness of the diesel technology in other parts of the world. Adoption of the proposed Euro 6 OBD thresholds should therefore support the future competitiveness of diesel technology.
(22)The Commission review of the feasibility of the Euro 6 OBD thresholds should focus on the technical feasibility of the proposed thresholds for compression ignition vehicles and the particulate OBD thresholds for positive ignition vehicles. This review should consider the state of development of new exhaust sensor technology, such sensors for particulate matter and particles and also the development of pressure sensing and modelling techniques for predicting the soot loading levels of particle filters.
(23)In addition, the Commission intends to review whether it is necessary for OBD thresholds for both particulate mass and particle number to apply at the Euro 6 stage. At this stage it is difficult to envisage whether particle number thresholds will be technically feasible.
(24)The Commission intends that the review of OBD thresholds should take place before 1 September 2010.
(25)In addition to the OBD thresholds, the Commission intends to keep under consideration the functioning of the OBD in-use performance ratio requirements. This includes the publication of guidance, where it appears to be necessary, and in particular for:
- incrementing and disabling the general denominator as well as numerators and denominators of individual monitors; and
- the statistical tests to be used by manufacturers for demonstrating compliance with the in-use performance requirements.
(26)The Commission will also consider introducing the World Harmonised OBD malfunction classification requirements from the mandatory application of Euro 6 limit values.
Table 1: Proposed Euro 6 OBD threshold limits
Reference mass(RW)
(kg) / Mass of carbon monoxide / Mass of non-methane hydrocarbons / Mass of oxides of nitrogen / Mass of particulates / Number of particles
(CO)
(mg/km) / (NMHC)
(mg/km) / (NOx)
(mg/km) / (PM)
(mg/km) / (P)
(#/km)
Category / Class / PI / CI / PI / CI / PI / CI / PI(1) / CI / PI(2) / CI
M / — / All / 1500 / 750 / 100 / 140 / 90 / 140 / 9 / 9 / 1.2 x 1012
N1 / I / RW≤1305 / 1500 / 750 / 100 / 140 / 90 / 140 / 9 / 9 / 1.2 x 1012
II / 1305RW≤1760 / 2700 / 940 / 130 / 140 / 110 / 180 / 9 / 9 / 1.2 x 1012
III / 1760RW / 3400 / 1100 / 160 / 140 / 120 / 220 / 9 / 9 / 1.2 x 1012
N2 / - / All / 3400 / 1100 / 160 / 140 / 120 / 220 / 9 / 9 / 1.2 x 1012
Key: PI = Positive Ignition, CI = Compression Ignition
(1) Positive ignition particulate mass standards apply only to vehicles with direct injection engines
(2) x2 threshold to be considered once emission limit is set
[1]In order to simplify its structure this table presents the provisions for M1 vehicles only.
[2]The OTLs specified in this table would still have to be agreed, i.e. could be different from the ones suggested in the "compromise proposal".