Beatrice Lopez, Christoph Albus, Stephan Redmann 23.02.2012

AWLTP - CO2 representativeness – influencing factors

A 1DHC

A1.1 / Test cycle / – assessment: will not change situation with NEDC
- DHC data base is near EU-database - conclusion: probably representative
A1.2 / Mode construction / Influence low
A1.3 / Gearshift provisions / Will lead to a reduction of CO2 emissions during WLTP testing, because the gearshifting points will be optimized to efficient engine map points
A1.4 / Tolerance (+/- v) / Aim should be to reduce the flexibility and influence of the test driver. In addition this will increase reproducibility
A1.5 / Influence of coldstart
(reality versus test)
/ -- Because of the cycle length (DHC = 2x NEDC) the influence of the coldstart is reduced in DHC
– not representative, because average trip length in Europe = 8 km)
-- (DTP) –test temperatur (25 °C) is the engine temperature at test start – not realistic, because average temperature in Europe is much lower – possible correction solutions:
a) weighting factors (cycle parts)
b) correction factor of the emission results
c) additional test at low temperatures

A 2DTP

A2.1 / RLD
A2.2 / Mass / See document DTP-07-12-rev (NL)
A2.3 / Lab-Temperature / See A1.5
A2.4 / Test stand load setting / Tolerances as low as possible, …
A2.5 / Cooling fan / Low influence
A2.6 / Test vehicle / See A3

A 3Certification issues and other TA requirements on European level

Remark 1: See list of certification issues in document – WLTP-DTP-LabProcICE-063.

Remark 2: Clarification which item can be adopted by comitology, and which items need co-decision.

Remark 3: Confirmation from Com needed.

A3.1 / Scope and application ?
A3.2 / Number of tests / number of vehicles / See also family concept (A3.3
A3.3 / Family concept
A3.4 / Durability / COP / ISC
A3.5 / “feedback approach” / See WLTP-DTP-LabProcICE-040
A3.6 / 4 % Rule
A3.7 / Self Testing (manufacturer)
A3.8 / Virtual testing
A3.9 / Mass definitions (whole chain) / Test, certification, other measures (CO2 regulation, labelling)
A3.10 / Extensions rules for approvals
A3.11 / Multistage concepts
A3.12 / Additional certification issues (without direct CO2 impact) / Items from LabProcICE OIL:
-handling 4WD vehicles on 2WD dyno
-Reporting requirements [test report, technical documentation….]

A 4MAC, Auxiliaries (energy consumers), Eco-Innovations

  • Separated evaluation of additional fuel consumption of vehicle types, where the effects are not covered by WLTP:
    -- MAC
    -- Other auxiliary energy consumers on board
  • Positive effects by eco-innovations (formally approved) or other technologies, not covered by WLTP (e.g. thermo management, heat storage)

A 5Vehicle in use

A5.1 / Driving behaviourand vehicle use (urban, rural, highway, traffic conditions)
/ It can be assumed, that the database used for the DHC development is covering real driving situation (also in EU). Differences in driving behavior and vehicle use in real life should result in a equal distribution +/- around the CO2 type approval value.
A5.2 / Durability
-- engine/transmission
-- rolling resistance of bearings (e.g. wheel)
/ No negative effects can be expected – only in case of serious defects.
A5.3 / Tyres, tyre pressure
A5.4 / Higher masses (payload)
A5.5 / Increased air resistance (e.g. luggage rack)

BCorrelation exercise and control of success

B1 / Assessment of repeatability and reproducibility after validation phase 2, confirmation test and round robin test (general condition for gtr adoption) / Part of the Technical Report
B2 / EU - correlation exercise (CO2) – regarding CO2-Regulation / Responsibility DG ENTR or DG Climate ?
Timing ?
B3 / Aim of control of success (CO2): Assessment of future CO2 values from type approval regarding their applicability for measures like labelling, taxation, incentives. / Comparison WLTP & future regulation with NEDC & current regulation
B4 / What is representativeness / real world ?
/ “statistical average”
B5 / EU-Correction factors needed (e.g. lab-temperature) ?
B6 / EU-Cycle mode weighting needed ?
B7 / Eco innovations / How to address in a comprehensive concept ?
B8 / Energy consumption of auxiliary devices / How to address in a comprehensive concept ?

CTiming /phase in of WLTP

C1 / Roadmap / Detailed roadmap (items / timing) provided by COM?
C2 / Different approaches for pollutants & CO2? / If WLTP will be implemented for CO2, on what basis will pollutant emissions be tested? Double testing?
C3 / OBD requirements / Thresholds are linked to cycle
C4 / Timing for pollutants should be adapted to other steps (MAC, RDE, Evap, ...)
C5 / Amendment of Regulations concerning the certification issues – possible with comitology ?
C6 / Transposition of WLTP-gtr with UN-R 83, a new UN-R, or via EU-Regulation ?
C7 / Correlation of the CO2 target values (95 g/km, ...) by DG Climate.
/ Important: at that point in time all CO2 relevant type approval requirements should be finalised amended (one shot) !
C8 / Relationship to other CO2 requirements (GSI, fuel economy meter)