>It became clear that it would be impossible to create diesel engines which would comply with enviromental standards Absolutely not "impossible" FFS, VW was ch

>It became clear that it would be impossible to create diesel engines which would comply with enviromental standards Absolutely not "impossible" FFS, VW was cheating to avoid using a proper adblue system, which would have been perfectly sufficient. They could also have used a particulate filter and burn off scheme like some trucks but that would require significant engineering and probably doesn't work as well with a small diesel engine. Orrrrrr they could have just done what the "cheat" mapping did: Run less lean. The entire point of cheating was to run very lean to make artificially high fuel efficiency figures. The cheat map for emissions would then run richer to kill off nox emissions. I genuinely believe they still "cheat" somewhat. My 2018 GTI has a 2L turbo engine. The MK7 GTIs were the first to be EPA emissions rated at 89 octane gas, even though the power figures are still recorded using 91 octane gas. Previous GTI engines were EPA rated with 91 octane gas. My tinfoil hat theory is that they run EPA tests on 89 octane so that it runs rich and reduces combustion temp, reducing nox emissions. Using higher octane fuel runs much leaner, and demonstrably produces better miles per gallon. They purposely chose to advertise a lower miles per gallon figure because, IMO, they couldn't pass emissions with the leaner burning 91 octane. Notably, low RPM (and emissions testing RPM) performance is utter garbage with 89 octane fuel, and the car becomes very stall happy, when at 91 octane it is very difficult to stall.