Environment and Climate

Global WLTP roll-out for more realistic results in fuel consumption

Questions and answers regarding the new international test procedure: Lawmakers require standardized test procedures to measure how much fuel a car consumes and whether it complies with the emissions limits. The new “Worldwide harmonized Light-duty vehicles Test Procedure” (WLTP) will apply to the type approval of new passenger cars across the EU since September 1, 2017. It will succeed the NEDC (New European Driving Cycle), which has been in force since 1992. It comprises both a new driving profile on test benches as well as more precise and up-to-date conditions for the entire test and is therefore intended to result in more realistic consumption data. What are the implications of the change? Seven questions, seven answers.

In welchen Schritten wird der WLTP eingeführt?

Since September 1, 2017, type approval in Europe will be possible for new passenger car types only if the results of valid CO2 measurements according to the new WLTP (Worldwide harmonized Light-duty vehicles Test Procedure) are available. Certified WLTP measurements must be available for all newly registered cars just one year later, on September 1, 2018. The regulation shall apply a year later for larger, light commercial vehicles as well. The European Union will be assuming a pioneering role internationally with the prompt implementation of the WLTP after its ratification by the relevant UN body. The test procedure, in modified form in some cases, will also be established in other regions of the world.

The WLTP’s rapid roll-out represents an ambitious goal for the participating testing organizations, the authorities responsible and automotive industry companies. It was not permitted to issue the official certificates on the fulfillment of the type-approval requirements until after the EU directive had been published and entered into force. This formal legislative act took place only recently on July 27, 2017. Furthermore, strict requirements have been placed on the test implementation, results evaluation and their documentation. The effort required for each individual test according to the WLTP procedure is also significantly greater than before: not only because the new test cycle itself takes 50 percent longer, but primarily because several versions of a vehicle have to be tested. As a result, the influence of numerous individual equipment options, wheels and tires on CO2 emissions must be determined separately in advance of the actual laboratory tests and must be witnessed by the technical testing services that accompany the measurements. Experts speak of approximately twice the effort involved for the determination of fuel consumption values.

Certified WLTP measurements must be available for all newly registered cars just one year later, on September 1, 2018. Of course, not every single vehicle produced is tested. Instead, cars are put on the test bench as sample vehicle types. Once the values are available, the manufacturer guarantees that the newly produced vehicles are technically equivalent to the type tested in the approval procedure with a certificate of conformity. This certificate is the prerequisite for the authorities to issue a motor vehicle title, which is used to register the vehicle later to this procedure. The European directive does not allow for any exceptions. Even passenger car models that are produced only in small quantities must go through the entire WLTP procedure. For larger light commercial vehicles, which often are technically based on passenger car models, the deadline will be extended by one year.

The European Union has assumed the pioneering role internationally in order to incorporate the new test procedure, which has been drawn up by a United Nations body, fully into existing legislation. In the coming years, India, Japan and South Korea are expected to follow with their roll-out of the WLTP. Japan is likely to waive the high-speed part of the new driving cycle due to its local road conditions. A modified WLTP procedure is currently under discussion in China, the largest passenger car market in the world. Although the USA was initially involved in the development of the WLTP, it is not yet clear that the new test cycle will be adopted into national law there.

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