Understanding WLTP

A driving cycle defines the requirements and conditions for measuring a vehicle’s fuel consumption and CO2 emissions. The goal is to simulate a realistic, average journey with the vehicle. The driving cycle specifies certain conditions such as the starting temperature, speed and measurement duration to ensure that the manufacturers can provide comparable values when registering and selling a vehicle. 

The New European Driving Cycle (NEDC) was introduced by the European Union on 01.07.1992. It was intended to guarantee a standardised means of determining the vehicle-specific emissions and consumption and ensure better comparability between vehicles. However, it does not claim to reflect the actual day-to-day consumption.

The Worldwide Harmonized Light-Duty Vehicles Test Procedure or WLTP was introduced in September 2017 and represents a new, worldwide standard cycle. WLTP utilises a profile more similar to actual daily driving behaviour than the previous NEDC standard. The new procedure is intended to provide a more realistic representation of a vehicle’s consumption. This is based on a modified test cycle with stricter test specifications. 

The NEDC testing cycle introduced by the European Union in 1992 is outdated and cannot accurately represent individual, day-to-day driving behaviour. In contrast, the new WLTP standard aims to guarantee that the emissions and consumption values measured during a model’s type approval testing reflect the values under real operating conditions. That is why both the procedure and the driving cycle differ from the NEDC standard.

For example, the redefined test parameters include a longer testing distance, longer driving times, shorter idle times and higher average speeds. They also take into consideration optional extras. These new parameters generally result in higher consumption specifications.

As of 01.09.2018, all new vehicles and all new passenger cars will require consumption and exhaust specifications as per WLTP. 

No. At present no changes to the model portfolio are planned. Individual models and their engines will have to be optimised in order to achieve even higher efficiency and reduce emissions as per the regulations. However, models will not be discontinued as a result of WLTP. 

Yes, there are. The driving cycles for exhaust and consumption measurement developed in Japan (JC 08) and the USA (FTP 75) are more closely oriented on specific situations on the country’s roads. For example, Japan’s driving cycle includes numerous stop-and-go phases and is carried out twice, once as a cold start and once as a warm start.