From 1st September, all vehicles must be approved according to a new protocol for measuring their emissions and consumption: the WLTP, closer to reality than the current NEDC. Precisely on the bottom, this evolution risks perverse effects in January 2019.
What to choose the long-term indictment of the approval standard for NEDC vehicles (1), which entered into force in 1973. As a result of consumption2 and polluters announced by manufacturers far from reality. But from the 1st In September 2018 all vehicles (except those at the end of their lives or in stock) must be subjected to a new protocol, whereby the WLTP (2) is supposed to better reflect the actual use of the car.
A protocol closer to reality
The new WLTP procedure offers longer test times, higher speed limits and more complex measurements. For example, in cold start (14 ° C) four speed ranges are measured on the test bench with rollers: up to 60 km / h, up to 80 km / h, up to 100 km / h and more than 130 km / h. During these phases the vehicle accelerates and brakes constantly and the maximum speed is 10 km / h higher than that of the NEDC. In addition, the average speed is about 47 km / h (about 33 km / h for the NEDC). The temperature in the test chamber is set at 23 ° C, while for the NEDC it is between 20 and 30 ° C. The WLTP procedure lasts about 30 minutes against just 20 for the NEDC. The distance "traveled" has also more than doubled from 11 to 23 km. Finally, in contrast to the NEDC, the WLTP takes into account optional equipment that influences weight, aerodynamics, rolling resistance and electrical requirements ("rest" flow). That is why manufacturers have to test at least basic and high-quality finishes for every model that is equipped with the same engine. On the other hand, optional equipment that requires power, such as air conditioning or heating, remains disabled during the test procedure, as before.
A double display
In fact, the WLTP protocol came into force in September 2017 for new vehicle models, without manufacturers having to mention these records. Since then, the homologated cars & # 39; s NEDC and WLTP have co-existed, protocols incomparable between them! In order not to disadvantage new cars compared to old models that are still approved in the NEDC, the European Union has set up a transitional mechanism called "CO2MPAS", which makes it possible to use the WLTP values. To extrapolate NEDC correlated values. . Manufacturers can still display this value in anticipation of the display of WLTP values in January 2019. And to make matters worse, until January 2021, the two values (correlated NEDC and WLTP) can coexist.
The imbroglio of CO2
If we can be satisfied with this new approval procedure, which gives figures that are closer to reality, there is the problem of CO-linked taxes2 (ecological bonus / malus, TVS for companies …). In concrete terms, this means that the official values for consumption and vehicle emissions increase between 25 and 40%! This leap into "official" CO emissions2 It is indeed likely that some models tip in a much heavier tax category. Another perverse effect, knowing that diesel engines (at comparable power) emit less CO2 that gasoline engines, does not it take the risk that this motorization finds thanks to its intrinsic defects thanks to the eyes of motorists?
(1) NEDC: new European driving cycle.
(2) WLTP: globally harmonized test procedures for light loads, which can be translated as "globally harmonized test procedure for light vehicles".