What is Euro 6/VI?

Euro 6 is the latest standard for the reduction of polluting emissions from road vehicles formulated by the European Commission.

Specifically, this standard has introduced interesting changes regarding light vehicles (passengers and goods) fueled by petrol and regarding the approval protocols.

Compared to the previous standard (Euro 5 / V, EC Regulation 715/2007), the limitations on emissions of polluting substances (CO, HC, NOx) have not changed in principle, while the limit on emissions of fine dust (PM) has become more restrictive. Here are the limit values ​​introduced with Euro 5 that we also find with Euro 6:

  • CO: 0.5 g / km for diesel, 0.1 g / km for gasoline
  • Nox: 0,08 g/km for diesel, 0,06 g/km for gasoline
  • PM: 0.005 g / km for both diesel and petrol → this is the only limit value which, with the Euro 6b variation, changes and becomes 0.0045 g / km

So far there are no major upheavals: in fact, Euro 6 is outlined more than anything else as an implementing measure of the objectives previously set out in EC Regulation 715/2007 (Euro 5 and Euro 6), and provides guidance on measurement methods for emission limitations, rather than on the limitations themselves.

When did it come into force?

This regulation is divided into 5 variations (Euro 6a, Euro 6b, Euro 6c, Euro 6d-temp and Euro 6d) which have been introduced in a very short time (the last one entered into force a few months ago).

Let’s see specifically the characteristics of each variation and understand what they have entailed for manufacturers and consumers:

  • EURO 6a: it was the first version of the Euro 6 standard (EC regulation n. 692/2008). It defined the implementation measures of the EC Regulation 715/2007 and the necessary requirements for the approval, establishing as the starting date for the Euro 6 phase on 1 September 2014;
  • EURO 6b: the Euro 6b regulation came into force in 2014 on homologations and in 2015 on registrations; in matter of important changes, it has defined the new limit value for particulate emissions for petrol and diesel (from 0.005 g / km to 0.0045 g / km);
  • EURO 6c: the Euro 6c entered into force in 2017 on homologations and in 2018 on registrations. He introduced at least 2 important changes:
    • a new parameter for the measurement of PM emitted by direct injection petrol vehicles, which is based on the number of particles emitted (up to now the limit value referred only to the mass, expressed in g / km). The new limit is 6 × 1011 p / km (600 billion particles per km);
    • a new homologation protocol, the WLTP (Worldwide harmonized Light vehicles Test Procedure), which provides more realistic and updated data on consumption and emissions compared to the previously adopted cycle (the homologation cycle used before the WLTP is the NEDC, dating back to 1992 and last updated in 1997!)
The last versions

We then enter the last phase of Euro 6, the Euro 6d, which is divided into two stages:

  • EURO 6d-temp: the first stage has a validity period September 2018 (homologations) / September 2019 (registrations) – January 2020. With this version, two other instruments are added to the WLTP homologation cycle: the road homologation cycle RDE (Real Driving Emissions) and mobile measuring devices, PEMS (portable emissions measurement system), for the measurement of Nox and PM. This way, the commission wanted to minimize the risk of a second dieselgate.
  • Euro 6d: the last stage of the Euro 6 standard comes into force in January 2020 on homologations and in January 2021 on registrations. In this phase the compliance factor (that is the allowed difference between the results obtained in laboratory and those gained on the road) drops from 110% as it was with the Euro 6d-temp, to 50%. This translates into a further reduction of the NOx emissions allowed.
What has changed for manufacturers and consumers?

As can be seen from this brief excursus, the legislation on polluting emissions limitation is constantly updated and it is very difficult for manufacturers to comply with it within the deadlines and without incurring onerous costs.

To comply with the limits, in fact, they must from time to time make technical changes to the engines, for example: 

  • with the Euro 6c and the limit on particulate emissions for gasoline, it has become mandatory to install petrol particulate filters (GPF)
  • with the Euro 6d and the strict limitations on Nox, the selective reduction catalyst (SCR) has been added to diesel light vehicles.

Of course, these changes also had consequences for drivers, both in terms of purchase choice and in terms of operating and maintenance costs for their vehicles.

Not only do consumers have to be more careful when they buy, in order not to risk buying a vehicle that is not approved according to the current standard, but they must also keep up to date with regard to the traffic restrictions imposed by some municipalities, to avoid finding themselves having a car with which they cannot move.

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