ACEA RDE Cold Start 30 th August 2016
CONTENT Introduction Cold start calculation method : approach 0 vs approach 2a Factor Cold Start (Fcs): proportional factor to integrate the severity of soaking temperature Timing Conclusions 2
COLD START: INTRODUCTION General Remarks: ACEA recognises the demand from regulators to include the cold start phase in the regulation of real driving emissions. Furthermore ACEA respects the political intention for the cold start phase to become operative from the start of the first RDE step, from September 2017. Due to the fact that there is effectively zero lead-time left until 09/2017, the following constraints for cold start regulation must be respected: In conformity with the overall RDE approach, the cold start regulation should assure that vehicle emissions certified on the basis of type approval tests on vehicle dynamometer will be found as equivalent under real driving conditions. A higher stringency compared to type approval regulations, i.e. a deviation from an equivalent transfer of requirements from type approval to real driving, will require considerable technological development, which will - if even feasible not be achievable within the considered time frame to the first RDE step. Additional efforts for testing and assessment of RDE cold start emissions should be kept as low as possible. This includes type approval and in-service conformity testing. No data base available to evaluate the impact on the PN at cold ambient temperature during engine start. 3
COLD START LEAD TIME 2015 2016 2017 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 legislation / publication Development time / done on current regulation or expected reasonable regulation Type Approval SOP (Start of Production) No time to change Software Hardware RDE Step1 (with unregulated Cold Start) No time for development before EURO6d- Temp Cold start conditions are not defined yet. Only regulatory text available (2008R0692) 2008R0692 Article3 9. The Type 6 test measuring emissions at low temperatures set out in Annex VIII shall not apply to diesel vehicles. However, when applying for type-approval, manufacturers shall present to the approval authority with information showing that the NOx after treatment device reaches a sufficiently high temperature for efficient operation within 400 seconds after a cold start at 7 C as described in the Type 6 test. Less than one year before first type approval deadline: Not possible to develop again hardware/ only some calibration adaption possible For PN / hardware already fixed à not possible to introduce change very quickly à PN postponed to Eu6d For gaseous emissions: impact must be manageable by the calculation method / Fcs 4
COLD START ANALYSIS OPTION 0 / OPTION 2A Option 2a would use formula sensitive to d urban Option 0 would simply include the 1st 300s in the Urban and Total Trip analysis Reducing d urban increases influence of emissions from the first 300s on the M urban calculated result. 5
DIESEL EURO6 SCR - NOx RESPONSE VS. D URBAN Engineering target vs. PEMS variability Cold Start results from Option 2a showing the effect of reducing d urban Difference is: Monitoring = w/o 1st 300s Option 0 = with 1st 300s Urban results from Option 0 Urban results from Monitoring Phase calc. method Analysis using Option 2a with low d urban shows results can exceed the NTE limit under nominal driving / 25 C temperature this is tougher than base EU6c legislation based on WLTP 6
DIESEL EURO6 SCR - DRIVING STYLE AND AMBIENT TEMPERATURE 3 C Severe driving? (data not yet available) Measured data Still a tough challenge Testing at the RDE boundaries e.g. 95% ile driving and 3 C ambient conditions multiplies the effect of reducing d urban to the point where new technology would be required for diesel vehicles with no time to deliver. à Already a tough challenge with Option 0 This would also be the case for gasoline engine vehicles 7
COLD START EMISSIONS EU6D VEHICLES* (1/2) PN Durban = 23 km NOx Durban = 23 km Hardware and emission calibration already done: EU6 vehicles fulfill CF(warm) New requirement of urban w cold start leads to exceedance of CF, for both NOx and PN Extended factor x1.6 covers only warm engine conditions New cold start requirement was not included in EU6.2 engineering assumptions Extended factor x1.6 applies to warm engine conditions and is not sufficient Need an acceptable integration of cold start during first 300s similar to Type 6 regulation * No LCV s in the database. ACEA suggests the application of cold start to LCV s require further study. 8
COLD START EMISSIONS EU6D VEHICLES* (2/2) PN Durban = 8 km NOx Durban = 8 km Hardware and emission calibration already done: EU6 vehicles fulfill CF(warm) New requirement of urban w cold start leads to exceedance of CF, for both NOx and PN Extended factor x1.6 covers only warm engine conditions New cold start requirement was not included in EU6.2 engineering assumptions Extended factor x1.6 covers only warm engine conditions and is not sufficient Need an acceptable integration of cold start during first 300s similar to Type 6 regulation * No LCV s in the database. ACEA suggests the application of cold start to LCV s require further study. 9
CONCLUSION FOR THE CALCULATION METHOD Ø Approach 2a not acceptable: increase the emission, very sensitive to the definition of a fixed reference distance. Ø Approach 2a is inconsistent with mixing cold start from 300s w/o normalization tool with urban data from normalization tools Ø Approach 2a is in conflict with Hybrid testing proposal (inadaquate increase of dc and weighting of cold start) Ø Approach 0 must be applied: take into account real distance driven, easily integrated in the normalisation tool MAW and PB 10
COLD START CONDITIONS for Hybrid-Vehicles, modifications are required! 1 RDE trip: Must start by the urban phase (not an option) 2 Boundary conditions adapted to Urban and cold phase: Preparation soaking temperature: 2-30 C (moderate) soaking time: 6-56h (over the week-end / vehicle bonnet should be closed) minimal temperature requirement: T coolant, T oil not more than 2 C below soak temperature First sec First 8 to 20 sec idling after motor start and which are included in RDE emissions First 300s Minimum distance for cold start: 1,25 km (equivalent to 15 km/h for 300sec) v*a pos max criteria: 10,0 m 2 /s 3 (analog WLTP) Cumulated altitude gain: +1200m/100km / proportional to real distance (already integrated in package3 draft) Urban part Additional criteria for URBAN: Creeping speed 1-15 km/h <15% of urban time Average speed: v urban = 20-40 km/h only for speed bin / (15-40 km/h map base) Minimum distance for urban phase: 23km (% d urban : between 34% +10% and -5% only) 3 Factor cold start: during the 5 first minutes only for T ambient air <14 C (see dedicated slide) 11 11
FIRST 8-20 SECONDS: IDLING TIME cycle FTP NEDC WLTP RDE Idle-time 20s 12s 10s 8s Ex.: Boiling of water cannot be done in 0.0 seconds. Similar physical principal applies to catalyst heating. There is no technical solution yet to ensure lambda probe operation right from the start under all temperatures (thermoshock from condensated water). A compromise of 8 20s idling would ensure to represent the median of real life use (seat belt, seat adjustment, radio ) but is still a huge challenge compared to any known regulation. 12
FIRST 300 SECONDS: V*A POS v a pos 10.0 m 2 / s 3 During the first 300s vxapos should be smaller than 10.0 m 2 /s 3 Covers >90% of EU-WLTP data base Source: Heinz Steven V*apos < 10.0 m 2 /s 3 would ensure to represent nearly every known vehicle use case On the other hand it is a practical misuse prevention 13
RDE URBAN DISTANCE - COLD START (1) Annual mileage: 14.000 km Number of cold start: 2 / Tag è 720 cold start / year Route after a cold start, average: 19,4 km The typical distance following a cold start is 19,4 km 14
RDE URBAN DISTANCE - COLD START (2) RDE - Cold start WLTP database analysis Source: Evaluation Heinz Steven, data-analysis and certificate, Heinsberg WLTP analysis shows: Distances between shut-down time from 8h: median 26 km, average 55.6 km Minimum distance for urban phase: 23km is well supported 15
RDE COLD START FACTOR 14 0 Max. value Factor Cold-Start: Xxx decision with data Altitude: 1.6 Cold start = start of the engine up to -7 C : increase of the emission during cold phase, after treatment system not efficient (too cold) Regulation cycle type6 for EU or US have adapted emission level to integrate cold test with cold start Need to introduce a correction to take into account the cold start Actual CF (urban and whole trip) are excluding the cold start extended factor 1.6 temperature or altitude -7 URBAN COLD 300s URBAN HOT Consideration of the COLD-START emissions (NO x ) with a temperature depending linear factor. Proposal for the implementation: 1 Hz based division of the emissions in first 5 minutes of URBAN with a factor which is depending on the actual ambient temperature during the 6h of soaking right before the test. The emissions, during the 5 first minutes, calculated according to Appendix 4, shall be divided by a value Factor cold start F CS Cold start emission are integrated to the current tools and the CF urban and whole trip are calculated with the 5 first minutes corrected by the factor F CS 16
RDE URBAN PROCEDURE CALCULATION DURING FIRST 5 MINUTES - Consideration of the COLD-START emissions with a temperature depending linear factor. - Proposal for the implementation: division of the emissions of URBAN with a factor which is depending on the minimum ambient temperature in the 6h soaking right before the test. Factor Cold Start T ambient air ( C) Only for the first 5 min, apply the factor cold start Fcs regarding the T ambiant air if below 15 C. Factor extended can be apply: For T ambient air < 15 C during 5 first min, only if altitude >700m, For T ambiant air >15 C, no change: if T ambient air >30 C or altitude >700m Factor Cold Start F CS for 5 first minutes: F CS = -T ambient air /10 + 2,5 The emissions, during the 5 first minutes, calculated according to Appendix 4, shall be divided by a value Factor cold start F CS Cold start emission are integrated to the current tools and the CF urban and whole trip are calculated with the 5 first minutes corrected by the factor F cs 17 17