Shropshire Star

Latest diesel cars well below emissions limits, say tests

Research conducted by the German equivalent of the AA found that in real-world driving, some diesels emit almost no nitrogen oxides at all

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The latest diesel models from BMW, Vauxhall and Mercedes emit well below the legal limit of nitrogen oxide pollutants – and in some situations, emit virtually none at all.

That’s according to independent testing by the German equivalent of the AA.

Adac ¬¬¬– the Allgemeiner Deutscher Automobil-Club – conducted real driving emissions (RDE) testing on 26 new cars, comprising 13 petrol and 13 diesel, to measure their emissions of nitrogen oxides (NOx). It found that many models, even diesels, emitted far less than the 168mg/km allowed under current European emissions regulations – Euro 6d (Temp).

Diesel vehicles tested under RDE conditions are allowed to emit up to 80mg/km of NOx, but the European Commission has set a temporary conformity factor to allow manufacturers time to modify their cars to comply. The conformity factor is currently 2.1 times the 80mg figure, meaning cars can emit up to 168mg/km in RDE testing, but from January 2020 the 80g/km limit will be strictly enforced.

The commission is currently appealing against the European Court of Justice ruling to allow 2020’s limit to be set to a lower conformity factor of 1.5, or 120mg/km.

However, all but one of the cars Adac tested came in far below even the 80mg/km limit. There were some very impressive performances too – for example, the Mercedes C 220 d actually emitted no NOx at all during testing, while the BMW 520d and Vauxhall Astra 1.6 CDTi emitted just 1mg/km each.

The highest emissions were recorded by a Honda Civic 1.6 i-CDTi, but even that vehicle’s 101mg/km figure is still below the conformity factor of 1.5. The next highest was the Volvo XC60’s 56mg/km.

(ADAC/PA)

Thomas Burkhardt, vice-president of technology at Adac, said: “Our test results show that diesel technology can have a future. Should the EU Commission revise the conformity factor, then consumers must be assured that Euro-6d (Temp) vehicles already purchased or offered for sale meet the legal requirements.”

None of the 13 petrol cars tested emitted above the 60mg/km limit currently allowed under European regulations. However, most emitted more than the cleanest diesel cars, shattering public perception that diesel vehicles emit more NOx by default.

The findings will be welcomed by vehicle manufacturers, which are suffering with a global pushback against diesel-engined cars. They’re also reportedly facing difficulties in getting vehicles to comply with the RDE element of the new WLTP fuel economy and emissions testing procedures.

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