Porsche - WLTP testing

WLTP testing

WLTP testing

The Worldwide Harmonized Light-Duty Vehicles Test Procedures (WLTP) are the replacement for the New European Driving Cycle (NEDC) tests which were in use until 1 September 2018. Both the old and the new tests are designed to measure exhaust emissions and fuel consumption. The WLTP testing cycle is based on real-time data collected world-wide during road use – giving a better representation of everyday driving profiles. Every vehicle produced for the EU market is provided with a Certificate of Conformity (CoC document), which, in addition to other information, includes the CO2 emission values from the laboratory test. On the basis of this document, registration of the vehicle is possible everywhere in Europe.

Basic technical questions

1. What does WLTP stand for?

WLTP stands for "Worldwide Harmonized Light-Duty Vehicles Test Procedure". This test procedure for emissions and consumption values has applied to new type approvals of the classes M and N1 in the European Union since 1 September 2017 and has been mandatory for all new vehicles since 1 September 2018.

2. What does NEDC stand for?

NEDC stands for "New European Driving Cycle" and was the previous test cycle for determining emissions and consumption values.

3. How are the measurement methods changing?

While the NEDC determined the test values using a synthetic driving profile, the WLTP cycle is based on the globally determined data from real road traffic. As a result, the WLTP is a better representation of everyday driving profiles.

The NEDC comprises two driving profile phases: urban and extra-urban. This yields the combined CO2 and consumption values. The WLTP driving cycle, on the other hand, is divided into four phases with varying speed and acceleration profiles: low, medium, high und extra high. Each phase comprises a number of driving, standstill, acceleration and braking phases.

In addition to the driving profile, the measurement procedure for the WLTP was also revised and adjusted to current vehicle technology. Measurement and tolerance specifications, e.g. at which temperature a vehicle should be measured or how high the tyre pressure should be set, have been tightened significantly.

The new test cycle and the new test procedure are characterised by the following:

  • A more realistic driving style
  • Larger range of driving speeds/driving speed types (urban, interurban, motorway), whereby the consumer receives specific fuel consumption data for each speed type within the WLTP test
  • Longer test track
  • More realistic ambient temperatures, which are closer to the European average
  • Higher average and top speeds
  • More dynamic and more representative acceleration and braking processes
  • Shorter stopped duration in relation to the cycle length
  • Consideration of optional equipment: Specification of CO2 values and fuel consumption values for every individually configured vehicle, taking into consideration optional equipment (spoiler, sliding roof, trailer hitch etc.)
  • Narrowing of the measurement tolerances
4. What advantages does WLTP offer?

Due to these changes, the WLTP offers a more realistic basis for determining the consumption and emissions data of vehicles.

The WLTP test was developed with the aim of creating a global test procedure to harmonise the determination of pollutant and CO2 emissions and fuel consumption data.

5. Will WLTP put an end to the discrepancy between the values measured in the laboratory and those achieved in road use? / What is the difference between WLTP & NEDC? / How are the measurement methods changing?

The WLTP offers a more realistic representation of the existing road conditions than the NEDC. However, not all possible variations can be covered. In addition, each individual driver will have an entirely individual driving style: while one person will accelerate more quickly, drive faster into the bend or brake more abruptly, another will drive more cautiously. In real operation, external conditions such as the weather (e.g. headwind, different temperatures), use (e.g. full load, towing a trailer), auxiliary facilities (e.g. radio, air-conditioning system) and route profiles (e.g. short trips only, motorway only) also play a part and all have quite a considerable influence on consumption.

Given the differences – which will continue into the future – in relation to driving styles, traffic situations and weather conditions in individual countries, the differences between the emissions and consumption values measured under laboratory conditions and those measured in the field will also continue to exist. However, as there is no such thing as one "true" emissions and consumption value from real world conditions, it is only possible to compare the emissions and fuel consumption of various models from different automotive manufacturers using the measured values recorded in standardised laboratory tests.

6. Which values (WLTP) will be measured on the roller test stand?

In laboratory tests within the framework of the European type approval for cars, the CO2 emissions that directly relate to fuel consumption, the pollutant emissions and the energy consumption values of alternative drives – including vehicles with an electric drive – are measured.

7. What is a type approval?

Laboratory tests play a key role in the procedure for launching a vehicle on the EU market. Before vehicles can be brought onto the market, they undergo specific tests carried out by a technical service in accordance with EU law. If all approval-relevant requirements are met, a national authority will issue the manufacturer with an EU type approval certificate, approving the vehicle type for sale in the EU. Every vehicle produced for the EU market comes with a certificate of conformity (CoC), which, along with other information, specifies the CO2 emissions values from the laboratory test. On the basis of this document, approval of the vehicle throughout Europe is made possible.

8. How can the driver determine the CO2 emissions of their vehicle?

So that car drivers can make a well-founded purchase decision on the basis of fuel consumption, car dealers and manufacturers provide the consumer with pertinent information, including a label stating the CO2 emissions and fuel consumption of a car, which is applied to all or near all new cars in the showrooms. The format of this label is determined at a national level (and thus differs from country to country). All labels, however, contain the CO2 values from the standardised laboratory tests, which are to be taken from the certificate of conformity (CoC).

9. What is the relationship between CO2 emissions and vehicle tax?

If, in an EU member state, the amount of the registration tax (one-off) and/or vehicle tax (yearly) is dependent on the CO2 emissions of the vehicle, this taxation is based on the CO2 values from the laboratory test, which are set out in the certificate of conformity (CoC).

Questions of relevance to customers

1. The WLTP method yields higher test results. Does this mean that my fuel consumption has increased?

In practice, the real fuel consumption will not change. In most cases, the WLTP test will yield a higher CO2 and consumption value than the NEDC test for one and the same vehicle, since the driving profiles and measurement boundary conditions (top speeds, dynamics etc.) of both test cycles are different. This means that the WLTP is a better representation of the present-day circumstances in road traffic than the NEDC. Due to the changed measurement process, therefore, the CO2 value according to the WLTP is closer to real customer consumption levels.

2. When did the changes come into effect?

The WLTP legislative package has been fully valid since 27 July 2017. This means that, since 1 September 2017, new vehicle types have been classified according to the WLTP. Since 1 September 2018, all new vehicles (new registrations) have also been classified according to the WLTP.

3. Why are the emissions standards changing?

At the start of 2018, the European Commission amended the legislation, which resulted in a change to the emissions classes planned and developed up until that time. These changes provide for different levels of emissions classes up to the final level, Euro 6 ISC-FCM.

4. Where can I find the current WLTP values?

The current WLTP values can be found on the model page for every vehicle. Vehicle-specific values for your specific vehicle configuration can be found in the Car Configurator.

5. I want Porsche to confirm that I will not be disadvantaged if my vehicle does not comply with the new standards. / Do I need to have my old Porsche checked?

It is not possible to give any additional commitments with respect to changing statutory or regional framework conditions.

6. Can I convert my vehicle from Euro 5 to Euro 6 (6d temp/6d)?

As things stand, it is not possible to retrofit a Porsche to a more recent standard while at the same time complying with our quality and safety regulations.

7. What is a petrol particulate filter (PPF)?

A petrol particulate filter is a particulate filter designed for petrol engines. It reduces the emissions of fine soot particles.

8. Why does my vehicle need a PPF?

In the past, particulate filters were known for use in diesel engines only; however, the increasing use of direct fuel injection technology rather than intake manifold injection in petrol engines is resulting in an increase in particle emissions. As the fuel is injected directly into the combustion chamber, individual droplets can precipitate on the cylinder wall, pistons or valves, where they can then be only partially burnt off and remain as the tiniest of soot particles.

9. How does the PPF affect the service life of the vehicle, and in particular the engine? /How much maintenance does the PPF require?

As with the particulate filters already in use in diesel engines, we do not expect to see any restriction in the service life of petrol engines equipped with a particulate filter.

No maintenance is required or foreseen. There is no impact on the service life of the engine, since the thermodynamic and mechanical limits of the engine unit continue to be observed. The regeneration of the filter generally takes place passively, meaning that the driver will not be aware that this is taking place. Only with longer operation of the vehicle with very low engine loads in conjunction with short trips and many cold starts will the operating parameters of the engine be actively adjusted so that regeneration can continue to take place (e.g. increase in gear-shifting speeds).

10. Does my vehicle have a particulate filter?

All our vehicles with petrol engines currently have a particulate filter.

11. Surely Porsche should be making every effort to ensure that I can continue to use my Euro 5 vehicle without restriction.

Porsche follows the political and media debate surrounding the identification of low-emissions vehicles very closely – including all the potential consequences for today's vehicle fleet. Essentially, we welcome and support considerations that serve for the benefit and protection of citizens. Accordingly, all the current models comply with the Euro 6 standards and therefore meet the latest requirements. Furthermore, Porsche supports the extensive measures of the Volkswagen Group, which were agreed during the "National Diesel Forum“, aimed at further improving the air quality in cities.

12. Can I obtain the blue disc from you? Note: The blue disc does not exist.

Porsche follows the political and media debate surrounding the identification of low-emissions vehicles very closely – including all the potential consequences for today's vehicle fleet. Essentially, we welcome and support considerations that serve for the benefit and protection of citizens. Accordingly, all the current models comply with the Euro 6 standards and therefore meet the latest requirements.

At the same time, please appreciate that it is beyond our power to offer solutions which remain under discussion and which have not yet been clearly defined to date. We hope, that our reference to our close attention to the topic makes it evident that Porsche is concerned with possible optimisations to the emissions performance of our vehicles as well as with the corresponding legislation.

13. When will the particle filter become available for all Porsche models (petrol engines)? Is a retrofit available?

Please appreciate that we are unable to make any specific statements on a possible retrofit of already registered vehicles with regard to model updates at this point in time. You may however rest assured that Porsche is closely monitoring the rapidly changing technology and legislation in this area and will respond accordingly.

14. Why does Porsche specify consumption in accordance with NEDC and WLTP?

In the German market, the national legislation regarding customer communication pertaining to CO2 and consumption values has not yet been converted to WLTP. For this reason, we must continue to disclose the NEDC values in the German market for the time being, and these are also the basis for the energy efficiency label calculation. Porsche also provides the WLTP values as voluntary additional information.

15. Do I need to have my old Porsche checked?

No. The conditions that were valid at the time of registration apply.

16. What does the conversion/homologation in accordance with WLTP have to do with the PPF?

In principle, nothing. The petrol particulate filter serves to fulfil the RDE (Real Driving Emissions) legislation.

17. What is the real consumption of my vehicle (neither NEDC nor WLTP)?

The real consumption is individually dependent on a wide variety of circumstances (such as external temperature, traffic situation, driving style, air pressure etc.). The WLTP will, however, probably provide more realistic CO2 emissions and consumption values.

18. What does RDE stand for?

RDE stands for Real Driving Emissions, and refers to the measurement of nitrogen oxide and particulate count emissions under real driving conditions.

Information for auditing companies and independent workshops

Additional Information on testing transparency according to the Regulation (EU) 2017/1151 as amended by 2023/443 Point 5.9 of Annex II of the European Union can be found within the "Technical Service Information" online application. If you have any questions, please contact piwisadmin@porsche.de.