In the recent news regarding Volkswagen's scandal for Euro 6 emissions, I've come to realise that Adblue is normally required for the reduction of NOx levels. The larger Ford engines use Adblue as do all other mainstream rivals (except Mazda skyactiv diesels), but how can Ford avoid Adblue on their smaller diesel engines?

PSA 1.6 BlueHDi and Ford 1.6 TDCi engines are shared plants. PSA uses Adblue and Ford does not. The 1.5 TDCi doesn't use Adblue and neither does the 2.0 TDCi 150/180. How can they reduce NOx levels to such an extent to pass Euro 6 emissions whilst using the same BlueHDi engines as PSA Peugeot Citroen.