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ADAC: Emissions from new Euro 6 diesels well below regulatory limits

22 February 2019

Tests by Germany’s ADAC (Allgemeine Deutsche Automobil-Club) showed that new Euro 6c and Euro 6d-TEMP diesel models produce NOx emissions well below the applicable regulatory limits. Twenty six Euro 6c/d-TEMP vehicles, including diesel and gasoline models, were tested on the road using the Real Driving Emissions (RDE) procedure. NOx emission from all vehicles were significantly lower than the RDE NOx emission limits (168 mg/km for diesel; 126 mg/km for gasoline).

NOx emissions from Euro 6c/d-TEMP vehicles in RDE testing

(Benzin = gasoline; Source: ADAC)

RDE NOx emissions from nearly all vehicles were also below the 80 mg/km WLTC limit. The only exception was the 1.6 i-DTEC Honda Civic, which produced NOx above 80 mg/km, but still comfortably below the regulatory RDE limit of 168 mg/km.

RDE testing and emission limits are applicable to Euro 6d vehicles. The limits are determined by multiplying the applicable WLTC NOx limit by a conformity factor (CF). Effective from September 2017 for new models and from September 2019 for all new vehicles, CF = 2.1 (Euro 6d-TEMP). Effective from January 2020 for new models and from January 2021 for all new vehicles, the CF is lowered to 1.43 (Euro 6d final).

Low Temperature Results. NOx emissions from Euro 6d vehicles are typically controlled using urea-SCR technology. ADAC also tested six Euro 6d-TEMP diesel vehicles at low ambient temperature conditions, to verify the effectiveness of SCR at low temperatures. The vehicles were tested on the road using the RDE procedure, at ambient temperatures ranging from -0.4°C to 7.9°C.

NOx emissions from Euro 6d-TEMP vehicles in low temperature RDE testing

(Source: ADAC)

Low temperature NOx emissions measured from the tested diesels ranged from the ultra-low level of 1 mg/km (two vehicles) to 56 mg/km. One gasoline car was also tested, producing 15 mg/km of NOx. All of the results were well below the respective RDE limits, as well as the WLTC values.

The ADAC results suggest that the introduction of the RDE testing requirements, in combination with other recent regulatory changes, may have finally solved the problem of high in-use NOx emissions that troubled European diesel cars for nearly two decades, culminating in the Volkswagen emission scandal.

Particulate emissions from diesel vehicles, including particle mass and numbers, have been controlled to very low levels using particulate filters since the Euro 5b stage, which became effective from September 2011 for new models and from January 2013 for all vehicles.

Source: ADAC