NEDC gives way to new driving cycle – higher consumption figure to be expected
Studies pointing out the differences in fuel consumption levels between laboratory tests and roads are published regularly. The German Association of the Automotive Industry (VDA) has already commented on this many times. The most important information on this subject is set out below.
The data on the fuel consumption of a vehicle are determined officially in special test laboratories in accordance with legal stipulations. The measurements are supervised by technical service and certifying organizations – for example by TÜV or Dekra. These technical service organizations are themselves certified by the German Federal Motor Transport Authority (KBA). The conditions for the measuring cycle are prescribed in such a way that there is hardly any margin for deviations during implementation. This is expedient, as the standardized laboratory conditions ensure comparability of the results. The individual consumption level of a driver may lie above or – with a corresponding driving style – below the standard consumption level.
If differences occur between the standard consumption and consumption in road traffic, this can be attributable to various factors, for example use of the air conditioning system, radio or seat heating, road conditions, driving style or weather conditions. All these factors strongly influence fuel consumption levels, but they are not taken into account in the NEDC measuring procedure.
The largest influence on consumption rates is exerted by the individual driving behaviour. Today, road traffic is more dynamic – and at the same time traffic jams occur more frequently. Both these aspects increase fuel consumption. The WLTP takes the currently more dynamic driving style into account. The NEDC, on the other hand, stands for more moderate driving. Tests in trade magazines also document that a moderate driving style can in many cases reach or even undercut the NEDC consumption level. The Odyssee-Mure study financed by the EU Commission (July 2015, http://www.indicators.odyssee-mure.eu/market-diffusion.html) comes to the conclusion that the average consumption of new vehicles is distinctly lower than that of earlier models. According to the study, the low EU average consumption rate of 5 litres/100 km in new registered cars is attributable above all to the high diesel share. The 11 EU countries in which the average consumption is below five litres have a diesel market share of over 70 per cent.
The German automotive industry is collaborating intensively in completing the new test procedure. Above all advantages and disadvantages of the old cycle have been channelled into the new WLTP. All organizations and member states of the UN/ECE area are invited to contribute to developing the WLTP and at the same time some of them are closely integrated into this development. In this way it is ensured that the WLTP takes sufficient account of all future aspects.
The WLTP driving cycle has been generated by real driving data gathered worldwide and therefore represents a globally average car journey. The primary goal of this revision is to map the peripheral conditions worldwide as well as possible.
The VDA assumes that on average the WLTP will lead to an increase in consumption data of over 20 per cent. Independently of the prevailing test cycle, German car manufacturers and suppliers will continue to work intensively on reducing CO2 emissions – in the laboratory and in real road traffic.
Further information is available at: https://www.vda.de/de/services/Publikationen/Publikation.~1235~.html