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The movement towards a global emissions testing procedure

Published: 12/31/2012
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The Worldwide Harmonised Light Vehicle Test Procedure (WLTP) will eventually bring tangible benefits for OEMs and consumers alike, although it is likely to be some time before it is introduced.

IHS Automotive perspective



There is an increasing movement towards establishing the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) so that OEMs can develop powertrains that can achieve emissions ratings through one universal testing procedure and test cycle.


The US, Japan and Europe all currently operate their own individual testing regimes and standards. If one test is adopted it means it will simplify the R&D and testing process for OEMs by removing technical barriers for different markers while reducing outlay on R&D, calibration costs and methodology development.


Given the diffuse and complex nature of global emissions testing regimes, and the various regional and national interests at play, it is likely to be some time before the universal test procedure and cycle is accepted. But 2020 is seen as a realistic date as to when the global standard could be adopted.

The global automotive industry is looking towards the implementation of a globally harmonised emissions testing procedure which will make life easier for OEMs in terms of reducing R&D costs and removing technical barriers to entering new markets. The move towards establishing the universal test is being overseen by the United Nations Economic Commission for Europe (UNECE) which originally established a technical working group to begin working out the test cycle for the Worldwide Harmonized Light Vehicle Test Procedure (WLTP) in 2008. This working group will work until 2014 on establishing and developing the main test criteria for WLTP. A second working group has also been established by the body to work on the more rarefied elements of the procedure such as testing in different ambient temperatures and at altitude. The test specification has been partly determined from data gathered from the "Unified" Global database. The construction of the Unified database has been based on contributions from the EU, Switzerland, India, Japan, South Korea and the US, and includes data collated in these countries over 660,000 km of defined in-use driving data that had been submitted as of May 2011, covering vehicle speed, idle, acceleration and deceleration.

The purpose of this work is to eventually form a global emissions test and procedure which will make the testing regime for OEMs easier in a number of key ways which will ultimately help reduce the cost burden of powertrain R&D. These will include:

  • Removing technical barriers on different markets
  • Reducing calibration costs and methodology development
  • Introducing globally relevant technology
  • Reflecting real world driving conditions
  • Respective national performance

Benchmarking According to the IHS Automotive's Powertrain division the movement towards a universal testing standard is increasingly viable as a result of the increasing convergence of Global non-CO2 emission "norms", specifically those governing particulate emissions and nitrous oxide (NO2) emissions. With the WLTP movement looking an increasing reality it also raises the prospect of fully global engine programmes. In addition, other regional testing regimes are attempting to align their own activities with the possible implementation of a global testing standard. For example the timescale for the implementation of the EU7 standard and associated limit values have not yet been announced and are probably contingent on WLTP progress.

Outlook and implications

This move towards a universal, global emissions testing standard would be very much welcomed by OEMs. It would simplify the testing and validation process of new powertrains considerably and reduce the amount of work in tailoring powertrains in order for them to meet differing testing criteria. The US, Japanese and European markets have their own testing standards in the form of FTP75/US06, JC08 and the New European Drive Cycle (NEDC), while other major markets such as the BRIC (Brazil, Russia, India, China) markets use regionally adjusted versions of the European and US cycles and procedures. And while the WLTP will simplify the current global system of testing regimes for OEMs, there is also significant potential benefits for consumers. WLTC should allow a more realistic interpretation of real world driving experiences, which will avoid the disappointment that is commonplace when consumers cannot match the claimed official fuel consumption figure when they buy a new car.

However, if the WLTP is adopted as a worldwide testing standard it could lead to some additional challenges for OEMs. The test criteria that is being proposed for the WLTP has some key differences to established frameworks such as New European Drive Cycle (NEDC) which is the European emissions testing criteria. For example with the proposed WLTC testing regime the engine operating area for engine speed and load is higher than on the NEDC test. This means that it could be harder to lower emissions on smaller, downsized gasoline (petrol) and diesel engines of the type which are increasingly prevalent in the Western European market. This could also harm fuel consumption and make meeting forthcoming EU6b and EU7 emissions standards increasingly challenging. There is also likely to be increasingly stringent criteria on non-CO2 emissions such as NO2. However aside from these issues the existing "in-use data" for the EU and US correlates well to the latest iteration of Worldwide Harmonized Light Vehicle Test Cycle (WLTC), the actual testing phase of the procedure, WLTC V5. However, this is less the case with Asia.

The full implementation of the WLTC will obviously require the full "buy-in" of all the relevant national and regional regulatory bodies, and all the major global OEMs. The US interest in adopting WLTC remains a little unclear, but this may prove an error over the longer term as failing to adopt WLTC could eventually leave the US industry isolated. Given the potential benefits to OEMs of the WLTC programme, it is likely that over time such resistance can be overcome. The final evolution of the WLTC procedure is due in 2014. According to IHS's Director of Global Powertrain forecasting Andrew Fulbrook, who provides the source presentation for this article, full international adoption of the WLTC testing regime is unlikely to take place before 2020 and is likely to be phased in on a country-by country basis. This adoption process will only take place after an enormously complex political process. There is little doubt that it is a highly complex issue which will take time to resolve, with input from all relevant interest groups and stakeholders. It is highly probable that the final procedure will have an even stronger effect on emissions control and therefore technology choice. This is likely to present further opportunities to component suppliers and engineering and technology sub-contractors, while the prospect of a global standard also means that completely global engine programmes will also become a possibility, with associated savings in R&D processes, certification and testing. With all these positives to be gained, it is likely to be a question of when, not if, WLTC is adopted as the global automotive emissions testing standard.

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