Opel has branded allegations aired by a German environmental organisation that the Zafira 1.6 CDTi emits levels of nitrogen oxides (NOx) up to 17 times higher than that prescribed under EU6 emission laws during rolling road testing as “false and unfounded”.
The allegations, made public in a press release issued on Friday morning, are based on a series tests carried out by the Bern Technical College in Switzerland under commission from the German Environmental Aid Association.
In its findings, the German Environmental Aid Association claims to have identified significant discrepancies in the emissions of the 118bhp 1.6-litre four-cylinder diesel-powered Zafira 1.6 CDTi (badged Zafira Tourer as a Vauxhall in the UK) during rolling road tests in which only the front wheels are turning and those in which all four wheels are turning.
Quoting results gathered by the Bern Technical College, the German Environment Aid Association said: “The measurements show that the vehicle behaves differently when the dynamometer is operated in four or two-wheel mode."
Furthermore, the German Environmental Aid Association says the amount of NOx generated by the front-wheel-drive Zafira 1.6 CDTi increases rapidly when accelerated to 150km/h (93mph) on the dynamometer in two-wheel mode.
The allegations aired by the German Environmental Aid Association has led to insinuations that Opel may have equipped certain models with emission manipulation software similar to that used by Volkswagen, or employed a defeat device that shuts off the injection of urea into the exhaust system at higher speeds.
Rebuffing the allegations in a letter issued to the media, Opel claims its own tests reveal the emission values of the Zafira 1.6 CDTi to be “absolutely correct and in accordance with the law”.