Following the Volkswagen emissions scandal, a German environmental pressure group has claimed that a Euro 6 version of the Opel Zafira has dramatically exceeded legal NOx limits during its tests.
German Environmental Relief claims that the 1.6-litre diesel engine fitted to the Opel (sold as a Vauxhall in the UK) Zafira Tourer emitted 17 times more NOx than the legal limit of 80mg/km.
The tests were carried out by the Bern Technical College in Switzerland. In its findings, the pressure group claims to have identified differences between the emissions of the 116hp 1.6-litre Zafira during rolling road tests where the front wheels and all four wheels were turning.
“The measurements show that the vehicle behaves differently when the dynamometer is operated in four or two-wheel mode,” it said.
The group also added that the amount of NOx increased substantially when accelerating beyond 93mph, causing the vehicle to exceed the lab’s measuring scale, during their tests, though this doesn’t fall within the normal emissions test format.
The lobby group suggested that one possible explanation is that the car varies the amount of emissions-limiting AdBlue solution injected into the exhaust system – which is required as part of EU 6 regulations – during their tests.
“The behavior could be explained by a shutdown of the AdBlue dosing. A similar behavior was not detectable during the four-wheel tests,” it said.
Allegations made by German Environmental Relief has led to suggestions in the media that Opel may have fitted manipulation software similar to Volkswagen to beat emissions tests, which employed a defeat device that shuts off the injection of AdBlue at high speeds.
“Opel emphatically rebuts the claims of German Environmental Relief. We would once again like to emphasize the following, valid for all our cars: GM developed software has no features that detect whether the vehicle is undergoing an exhaust emissions test,” Opel, Vauxhall’s sister brand said in a statement.
“The results of the alleged Zafira test conducted by the German Environmental Relief group are not comprehendible. It is not fair that German Environmental Relief makes assertions but did not disclose the alleged results,” it added.
Opel added that it re-tested a 1.6-litre diesel Zafira itself and that it complied with legal limits, which was overseen by TUV Hessen, an emissions testing body.
