The impact of WLTP

Under conditions defined by EU law, the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) laboratory test is used to measure fuel consumption and CO2 emissions from passenger cars, as well as their pollutant emissions.

What is WLTP and what could be the impact for your company?

WLTP is a new protocol to measure vehicles fuel consumption, CO2 and pollutant emissions. The procedure was developed by the United Nations Economic Commission for Europe (UNECE) to replace the current “New European Driving Cycle” (NEDC).

One of the main objectives of the WLTP procedure is to better align the test results with realistic vehicle usage, based on current engine technologies. Given the importance of CO2 targets for the economic performance of vehicle manufacturers worldwide, WLTP also aims to harmonize test procedures on a global level, in order to create an equal playing field in the market.

Beginning in September 2018 the WLTP will premiere and in 2020 NEDC is rendered obsolete worldwide.

5 important questions

  • 1. Will the new test cycle alter the consumption behaviour of the vehicles?
    No. The efficiency of the vehicles will not change as a result of the changeover to the new WLTP measurement procedure. However, the values determined under WLTP will reduce the difference between the previous NEDC consumption values and the values from road tests.

  • 2. Will WLTP lead to higher consumption and CO2 figures?
    Yes. Vehicles with combustion engines can be expected on paper to have higher consumption and CO2 values. The stated range of electric vehicles will be reduced. There will be no change when it comes to the actual consumption experienced by customers, as the vehicles will not change as a result of the switch to the new measurement procedure.

  • 3. By how much will the consumption and CO2 figures increase?
    As part of the changeover from NEDC to WLTP, VDA (German Association of the Automotive Industry) anticipates an average increase of 20 percent in consumption/CO2 values compared with the previous NEDC values.

  • 4. Will the WLTP values now finally reflect the actual consumption?
    The WLTP significantly reduces the difference between the figures in brochures and the average consumption values experienced by customers. Yet the WLTP values, too, are determined in the lab under defined test conditions, so that they are reproducible and comparable between individual vehicles and manufacturers.

  • 5. So does the same lack of reproducibility apply also to the RDE emissions tests?
    The RDE road tests verify that the prescribed limits for nitrogen oxides (NOx) and particulate number are not exceeded under on-road driving conditions after the legal factors are taken into consideration. An RDE test covers a wide spectrum of legally defined ambient conditions. This means that the emissions values will be lower than the certified values.

What is the difference between WLTP vs NEDC?

  • 3 test cycles in function of the weight-to-weight ratio instead of one uniform cycle
  • A cycle of 30 instead of 20 minutes
  • Cycles of 23.25 kilometers instead of 11 kilometers
  • 4 phases (instead of 2) with more simulations outside the urban area (87 percent instead of 63)
  • An average speed of 46.5 km / h instead of 34 km / h
  • Highest speed of 131 km / h instead of 120 km / h
  • The influence of some equipment elements on CO2 emissions is taken into account
  • Variable switching moments (not always at the same point) and Fixed temperature in the test room

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