German carmakers hope diesel exhaust fluid (DEF) could prove to be the clean little secret of an industry still reeling from the Dieselgate scandal. For around a decade, the liquid has been injected into the exhaust emissions of millions of diesel trucks in North America and Europe to turn harmful nitrogen oxides (NOx) into less harmful nitrogen and water. Although German carmakers pioneered the use of DEF in passenger cars, most drivers of these German diesels only became aware of the extra tank in their cars in late 2015. The revelation that Volkswagen Group’s cars secretly reduced injections of DEF when on the road came with the insight that they did this in part to save drivers dirtying their hands with the corrosive liquid.
The evasions of misguided paternalism have since then given way to full-throated marketing of Adblue, as DEF is dubbed in Germany. Consumer websites prizing the additive – which shares a main ingredient with urine – are splashed all over the German-language internet. The site www.findAdblue.com, for example, was recently launched by auto-industry heavyweights Bosch, Opel, VW, Audi, and Mercedes, and oil giant Shell. The website claims to provide “a free and independent service for finding Adblue dispensers at filling stations” – a once unimaginable imposition on customers.
As recently as 2012, Audi presentations contained anxious warnings that customers should not be allowed to “come into contact with Adblue.” As the mixture is corrosive, Audi and its German rivals deemed it inconceivable to ask customers to top up DEF themselves – indeed, the tanks were hidden under the spare wheel in some cars. Their sales departments also worried about the extra space needed for and weight added by DEF tanks as part of a so-called selective catalytic reduction system (SCR).