WLTP – the "second"

More than 90 percent of the Mercedes-Benz Cars fleet already comply with the strict Euro 6d-TEMP emissions standard (obligatory for all vehicles from 1 September 2019) or even Euro 6d, which will not be in place until January 2020 for new models.

Shortly after the introduction of the WLTP test procedure (Worldwide Harmonized Light Vehicle Test Procedure) major revisions were once again made to the provisions at the beginning of 2019. Just 20 days following publication of the latest EU regulation on the WLTP, this so-called WLTP 2nd Act has already entered into force and, starting in 2019, must be successively taken into consideration during certification. The Regulation 2018/1832 was published in the EU Gazette on 27 November 2018, and it has been in use since 17 December 2018. As of 1 January 2019 new measurements have to be carried out in accordance with the provisions of this regulation.

The changes are extensive: The regulation on the WLTP previously encompassed around 700 pages, and now with the 2nd Act another 300 pages have been added. Here you will find the most important changes:

  • With the 2nd Act, the EU Commission is assuming all changes to the WLTP framework directive decided upon up until mid-2018 at UN level (Global Technical Regulation No. 15 Amendment 4).
  • Changes to the provisions at UN level mean that specifications on the switching point calculation for manual selectors change, among other things. This means that switching points calculated according to the previous specifications may deviate slightly from a calculation according to the current specifications.
  • So-called Drive Trace Indices are also being introduced on account of the changes at UN level. Beyond testing the previous tolerances for deviation, these indicators are used to test whether the driver follows the driving cycle as precisely as possible.
  • The EU has adapted and/or added several provisions valid only in Europe that go beyond the changes to the UN provisions. These include, for example, the introduction of a driving cycle correction for all conventionally-driven vehicles, i.e. vehicles that solely have a combustion engine as their power source.
  • For all newly approved vehicles from 2021, the fuel consumption computationally determined in the vehicle (OBD - On Board Diagnose) may not deviate by more than +-5 % from the value determined in a WLTP Type 1 certification test at 23 °C on the roller dynamometer. The values determined in this way can also provide the driver with information on his fuel consumption in real-life driving. A vehicle's overall fuel consumption can be read out via the OBD interface.
  • The RDE Package 4 was also approved alongside the WLTP 2nd Act. In future, measuring drives will always be evaluated via a standardised tool. The measuring tolerance for nitrogen oxides in RDE Phase 2 (Euro 6d, obligatory for new models from 2020, for all new registrations from 2021) has been lowered from 0.5 to 0.43.
  • In addition, with the WLTP 2nd Act the scope of documentation has been significantly expanded. In future, manufacturers will provide the authorities with so-called “transparency lists” which contain all data with which authorised third-parties can independently carry out tests in future. It is anticipated that these transparency lists will be published from mid-May 2019 in a database supplied by the EU Commission.

  • The test procedure requirements to check fuel evaporation in vehicles with a petrol engine (the so-called Type 4 Test) was fundamentally revised in the 2nd Act.
    • Previously, for this test vehicles were subject to simulated sun rays (course of a day) for 24 hours in a test chamber. During this time, it was checked to what extent fuel which could not be absorbed by a filter in the vehicle evaporated from the tank.
    • In future, this test will last 48 hours, however the limits to be met have not changed, which means that the requirements have become significantly stricter.
  • All vehicles newly approved in the EU must fulfil the requirements of the new procedure (WLTP 2nd Act) by September 2019. They will receive a new letter combination in the CoC approval document (Certificate of Conformity) and have to be re-certified for this.
  • When testing field vehicles, the emissions behaviour of vehicles is checked using a sample from several vehicles. The vehicles
    • are at least 6 months old and also have at least 15,000 kilometres on the clock
    • are a maximum of 5 years old and have a maximum of 100,000 kilometres on the clock.
  • While in the past, only Type 1 dynamometer tests were carried out to check whether the values of the field vehicles corresponded with the legal requirements, in future RDE road tests will also be carried out with field vehicles.

Customer information under WLTP

The Directive on Energy Consumption Labelling of Passenger Cars currently regulates that customers must be informed, for example, in the car dealership or via advertising, of the official consumption and/or the CO2 emissions of a vehicle. This EU directive has to be transferred into national law in each member state so that the requirements for labelling (apart from the disclosure of certain values) is different in each EU member state. According to this, the customer must be informed of the official CO2 values of a vehicles; before the introduction of the WLTP these were the NEDC values. By the end of 2020, however, all vehicles will have a value according to the new WLTP test procedure and the NEDC.

The requirements for how the customer should be informed of a vehicle's official CO2 emissions and consumption value has not yet been adapted in many countries, and also not in Germany. Thus, information and identification (e.g. labelling) still take place using the NEDC values even though the WLTP was already introduced on 1st of September 2017 as the official procedure. Although the customer can find out about the WLTP values on a voluntary basis, this is linked with risks for the manufacturer since the information for the customer has to be unmistakeable. In the online Mercedes-Benz configurator, the customer can find out about consumption according to the WLTP by clicking on a separate icon. The delayed adjustment of the national regulations thus means that the more realistic values can only be made available to the customer upon his/her request and/or only as additional information.

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