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Detailed insights from meetings on in-use evaporative emissions, purging strategies, and cost/benefit analysis. Discussion on impact of ethanol, stakeholder views, compliance data, and technology feasibility.

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  1. Background • Meetings: 13th May 2011 and 22nd September 2011 • Presentations from JRC on: • Main issues concerning in-use evaporative emissions and impact of ethanol on evaporative emissions • Possible approach for the cost/benefit analysis of the proposed new measures • A questionnaire was circulated in order to collect information and comments from the main stakeholders • Presentations from other stakeholders: • Results from in-use compliance programme and parking time data (Swedish Transport Administration) • OBD systems • JAMA’s view

  2. Current situation • 9 filled-in questionnaires received • Member states: 1 • OEM Suppliers: 3 • Car manufacturers: 4 • Testing service company: 1

  3. Summary of the replies to the questionnaire

  4. Purging strategy and multi-day diurnal tests • It is clear from all the replies that purging strategy and carbon canister capacity are closely interconnected • The purging strategy mainly depends on the canister size, the number of diurnal tests and the conditioning driving cycle • Modest benefits would be obtained by increasing purging rate without extending the number of diurnals • The US 48-h diurnal test forces an aggressive purge and better ensures low off-cycle emissions control • The US 72-hours test provides additional benefits only if complementing the 48-hours test

  5. Purging strategy and multi-day diurnal tests • Adopting US procedures (e.g. 48-h test including cycles etc.) or developing a new EU procedure? • Different opinions even among automakers. Harmonization desirable but not practical (huge calibration and facility costs, lack of experience of both car manufactures and authorities about US cycles) • US certification for evaporative emissions accepted in Europe?

  6. Purging strategy and multi-day diurnal tests • Technical feasibility • No feasibility issue. • Technology exists. • Several EU automakers already supply vehicles meeting US requirements • US systems cannot be simply converted to Europe market but need to be modified/developed because of the differences between US and European procedure. Capacity of canister needs to be re-evaluated • The additional testing time will require additional facilities (cost of a SHED ranging from 0.5 to 1.2 MEuros)

  7. Purging strategy and multi-day diurnal tests • Main issues for European vehicles • Downsizing, turbocharging and other fuel efficiency measures reduce the availability of intake manifold vacuum and consequently purge rate and purging time. • Depending on the pre-conditioning and driving patterns adequate purging can result more challenging than for typical US applications • FTP-75 is a higher energy cycle compared to NEDC. • NEDC +2 x UDC proposed instead of NEDC+UDC • It is difficult to secure an adequate purge volume for hybrids. Specific technologies needed

  8. Purging strategy and multi-day diurnal tests • Possible impacts • Negligible impact on pollutant emissions • Possible impact on driveability (throttle response, idle quality) • To be covered by increased calibration efforts • Range (reduced in case of pressurized tanks) • CO2 : The impact is technology dependent (e.g. higher in case of pressurized tanks)

  9. Purging strategy and multi-day diurnal tests • Technology needed and costs • Bigger canister : 5 Euros • Engine calibration:1 M€ per engine/vehicle • Low purge rates issue: possible technologies • Purge air heating unit (50 -100 €) - Out of plan? • Hydrocarbons sensor (50 €) – Under advanced development • Pressurized fuel tanks (500 € +20 kg weight increase – 1 g CO2) • Out of plan for HEV • May be adopted for PHEV • Most likely technology but others preferred if they work • Passive carbon scrubber (4-8 €) • Honeycomb canister ??

  10. Fuel permeation • Technical feasibility • No feasibility issue. Technology exists. • Investments needed in order to adapt production lines. The supplier capacity in Europe has not been secured • Impacts • Use of more expensive material • Slight impact on weight. • Costs • Total: 25 € • Low permeation tank: 20 € but up to 150 € for some vehicles • Fuel hoses: 5 €

  11. Fuel permeation • Regulatory options • Running-in of vehicles carried out with E5 or E10 preferred option • Already carried out today ? • Potential issue: availability and cost of E5. • Lower emissions standards could results in higher costs for the use of more expensive material • Long soak period before testing and heating of tank (not >40 C) • Soaking period and conditioning have to be well defined - different transient permeations states could result in inconsistent emissions • Fuel system emissions are usually monitored during a 20 week soaking period at 40 C which provides a reasonable check of the impact of aging (more information needed)

  12. Durability • Technical feasibility • No feasibility issue. Technology exists. • Impacts • Use of more expensive material depending on durability requirements • Costs • Durability procedure • Component aging: 7.850-19.750 € depending on vapor loading rate and canister size (Only canister? Additional information needed) • Component aging: 250.000 € (All the components?) • Whole vehicle aging : 1 M€ • Evap test included in the in-use compliance programme: 15.000 € /test

  13. Durability • Regulatory options • Whole vehicle aging: Very expensive (1 M€) and no representative results expected • Self certification does not fit well with the European type approval model • Durability testing based on critical component aging: • US experience shows that it is difficult to develop an aging protocol consistent with in-field running conditions (SAE J1769 not approved but partially used). Slosh test much more severe that on-road conditions • Re-assembling of components potentially critical • Data generated for US certification accepted (linked to self-certification)? • For in-use compliance a detailed procedure is needed (state of vehicle, service history, correct fuelling, vehicle usage, cleaning fluids,…) • If necessary, in-use compliance programme preferred option (maybe coupled with component aging)

  14. OBD • Technical feasibility • Technology exists to detect 1 mm/0.5 mm hole as required by US legislation - US technology may need to be adapted to European environmental conditions • Purge flow OBDs are also available (O2 sensor or pressure sensor) • Liquid leakage can be detected only in the tanks when the liquid level is below the leakage point. • Hybrids: OBD function is not performed while in electric mode. If the same check frequency is required, pumps are needed • Impacts • No impacts on pollutant emissions with correct system calibration • Negligible impact on fuel consumption due to increased alternator load and increased vehicle weight • System noise maybe a concern for critical drivers and passenger

  15. OBD • Costs • Vehicle: Depending on OBD type • From 7.5 € to 17.90 € for leakage detection systems • 30-40 € hardware + 0.5 M€ for calibration (per engine/model) • Purge flow OBD systems • Use of O2 sensor: No hardware + 0.5 M€ for calibration • Use of pressure sensor: 10 € hardware + 0.5 M€ for calibration • Once OBD has detected a problem, significant efforts may be needed to identify and fix it – additional costs for users

  16. On-board Refueling Vapour Recovery • Technical feasibility • Technology exists. Widely used in US as well as in some European models • Infrastructure compatibility? (refueling flow rate, nozzle size,…) • Space in vehicle may be an issue although small cars are already sold in the US (e.g. Smart, Fiat 500, Mini ) • Reduction of vapour pressure? Being currently discussed in Europe but not likely • Impacts • Compatibility between Stage II and ORVR (slight reduction in efficiency of some Stage II system models - this can be solved in several ways) • Improved fuel economy due to fuel recovery (0.1 litre per refueling event) vs slight increase due to additional weight

  17. ORVR • Costs • Vehicle: • Overall cost increase about 15-20 € to (canister: 3-4 €, other components: 5-10 € , ORVR testing 2.000 € ) • Overall increase 60 € (canister 30 € + tank 30 €) + 1 M€ ORVR Shed, + 0,2 M€ fuel dispensing system + 1 M€ developement • Stage II systems • Installation: 30.000-45.000 € without vapor processor • With a vapor processor: 50.000-75.000 € • Maintenance: 5.000 – 7.500 € / year

  18. Purging strategy of vehicles available on the European market

  19. Purging strategy of different vehicles • PC - 1360cc 55kw Euro4 MPI Cumulative (l) Cumulative (l)

  20. Purging strategy of different vehicles • PC – 1197 cc 47 kW Euro4 MPI Cumulative (l) Cumulative (l)

  21. Purging strategy of different vehicles • PC - 1794cc 95kw Euro4 MPI Cumulative (l) Cumulative (l)

  22. Purging strategy of different vehicles • PC - 1798cc 92kw Euro4 MPI

  23. Purging strategy of different vehicles • PC - 1798cc 88kw Euro4 MPI

  24. Purging strategy of different vehicles • PC - 6063cc 313kw Euro4 MPI Cumulative (l) Cumulative (l)

  25. Purging strategy of different vehicles • PC - 875cc 62.5kw Euro 5 MPI Cumulative (l) WLTP Cycle (current version) Cumulative (l)

  26. Driving cycles energies Theoretical energy (kWh) required to cover different driving cycles Calculated for a vehicle having a mass of 1470 kg and using the dyno loads prescribed by the legislation

  27. Pressurized tanks • In general heavy steel tanks are used • E.g. SAE Paper 2005-01-3825 ”Design of a fuel vapour-containment system (FVS) to meet zero evap emission requirements in a HEV” • The tank is sealed while the vehicle is parked • Canister for refueling control only • Thick steel tank to withstand pressure changes due to temperature variation • Before opening the cap for refueling, open the valve to release vapor into the canister by using a dash board switch

  28. Pressurized tanks

  29. Pressurized tanks • Other technologies are emerging • E.g SAE Paper 2010-01-0831”Development of exhaust and evaporative emissions systems for Toyota THS II plug-in hybrid electric vehicle” • A FVS (Fuel Vapour containment System) tank was considered the most appropriate to control evap emissions. However conventional FVSs use a steel tank which is detrimental in terms of weight and ease of installation • FVS plastic tank covered with heat insulation was used in order to keep the tank pressure within the containment range

  30. Pressurized tanks http://ev.sae.org/article/9428 Tank Advanced Process Technology (TAPT) from TI Automotive is a plastic blow-molding manufacturing technique that provides flexibility to convert plastic fuel tanks into valued solutions. Developed as an enabling technology to optimize fuel-slosh prevention, the TAPT process allows for manufacture of pressurized plastic fuel tanks for the hybrid-electric vehicle (HEV) market. Because an HEV rarely uses the gas engine to purge tank vapors from the carbon canister in the emissions system, pressure can build over time and temperature rise in the fuel tank. TAPT technology allows makers of HEVs to convert from heavy steel tanks of today into quiet, lightweight plastic tanks on future applications.

  31. Pressurized tanks • Issues with sealed tanks: • Fuel tank will be under pressure (>2 psi); all the diurnal vapour will escape through any size leak any where in the closed system • Any size leak any where in the system results in uncontrolled diurnal emissions into the atmosphere • A small leak can go on undetected for long time

  32. Cost/benefit analysis: Use of COPERT 4? (The next slides have been provided by G.Mellios of Emisia S.A., a spin-off company of the Lab of Applied Thermodynamics / Aristotle University of Thessaloniki)

  33. Status of COPERT – Administrative Info • The name stands for COmputer Programme to calculate Emissions from Road Transport • Now in its COPERT 4 Version (fourth update of the original COPERT 85) • It incorporates results of several research and policy assessment projects • It is basically funded by the European Environment Agency through the budget of the European Topic Centre on Air Pollution and Climate Change Mitigation • It is scientifically and technically supported by Emisia S.A., a spin-off company of the Lab of Applied Thermodynamics / Aristotle University of Thessaloniki • It has recently attracted much attention from the Joint Research Centre in Ispra who are further supporting its technical development

  34. Who is using COPERT • COPERT 4 officially used for preparing national inventories by 19 MSs (+UK); MT, BG are working on this; 22 total • Published applications in Asia, L. America • Plans to build Australian version • Scopus returns 67 journal papers when just “COPERT” is used as keyword – few hundreds if one uses more options • ~800 software downloads per year – many more webpage hits

  35. Evap model in COPERT • Development based on following experimental data • Joint EUCAR/JRC/CONCAWE EVAP Programme • LAT/JRC/CONCAWE programme for updating COPERT • Older CONCAWE and various US studies (mainly for older vehicles) • Several tests on various vehicles • Based on a physical model for simulating adsorption – desorption on activated carbon • Covers all petrol vehicle categories (passenger cars, light commercial vehicles, mopeds and motorcycles)

  36. Curve fitting – canister weight (loading) • Exponential function: • a, b are linear functions of temperature & vapour pressure vapour load breakthrough emissions Vapour pressure effect Temperature effect

  37. Curve fitting – canister weight (purging) • Exponential function: • a, b are linear functions of temperature & purge rate purge volume Purge rate effect Temperature effect

  38. LAT/CONCAWE/JRC work • Tests on a VW Polo (completed) • 3 fuels at 60, 70 & 90 kPa • 3 temperature profiles (10-25°C, 20-35°C & 25-40°C) • Precondition: ~200 km on the road (adapt to new fuel) • Two consecutive diurnal tests (corresponding to low and high initial canister loading) • Permeation tests (canister vented out of the SHED) model calibration • Tests on 4 more vehicles (3 completed) • Fewer tests per vehicle • Same test protocol as for the VW Polo • (+ results from EVAP Programme) model validation

  39. Model validation: diurnal emissions Diurnal emissions of EVAP Programme considerably lower due to lowinitial canister load

  40. Parking time distribution • Parking duration distributed into 24 time classes ranging from <0.5 to >11.5 h • Each combination of parking duration and parking end-time has a probability factor fk • ∑fk = 1

  41. Parking time distribution

  42. For Euro 6 cost benefit analysis • Update emission factors to include ethanol blends • Update matrix on parking distribution based on real world data (GPS recordings) • Introduce other corrections based on new data available for Euro 6 vehicles: • canister volume and activated carbon mass (on the basis of suggested Euro 6 requirements) • activated carbon working capacity • initial canister load based on driving time prior to parking • efficiency decrease over vehicle lifetime, for different vehicle sizes

  43. Thank you! giorgio.martini@jrc.it http://ies.jrc.ec.europa.eu

  44. Evaporative Emissions from Vehicles • The current European legislation on evaporative emissions dates back to the Directive 98/69/EC (Euro 3-4 standards) • Since then neither the emission limits nor the test procedure have changed • As stated in several legislative document the European Commission has now the obligation to review the evaporative emissions test procedure in order to improve control of evaporative emissions.

  45. Evaporative Emissions from Vehicles • REGULATION (EC) No 715/2007 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL • Article 4 • 2. … In addition, the technical measures taken by the manufacturer must be such as to ensure that the tailpipe and evaporative emissionsare effectively limited, pursuant to this Regulation, throughout the normal life of the vehicles under normal conditions of use. ... • …In order to improve control of evaporative emissions and low ambient temperature emissions, the test procedures shall be reviewed by the Commission.

  46. Evaporative Emissions from Vehicles • Communication on the application and future development of Community legislation concerning vehicle emissions from light-duty vehicles and access to repair and maintenance information (Euro 5 and 6) - (2008/C 182/08) • Evaporative emissions • 9. Due to the wider introduction of biofuels, the Commission intends to review test procedures for evaporative emissions. This review should consider whether greater global harmonisation is desirable through alignment of the European test procedure with that used in the United States. In doing so, consideration may be given to introducing in-service conformity or durability requirements to control the effects of long term use of fuels containing ethanol on evaporative emissions.

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