Re: The affair is far from "largely concluded"
"I wouldn't, it's not difficult...
"All they need to do for lower NOx is increase fuelling at low power output to cool the combustion, that is what Exhaust Gas Recirculation (EGR) does. A simple engine remap will fix that, perhaps with a tiny (< 1%) fuel consumption penalty.
Well, I think that you are underestimating things slightly. For the medium-sized VW diesel engines, I believe that there are two categories; the larger cars have the 'AdBlue' system for NOx control, and the smaller ones, Exhaust Gas Recirculation.
As far as I am aware (and it may just be that I am not sufficiently aware) the AdBlue cars don't have the EGR hardware, so being a bit more generous with the EGR would not be an option here, but it doesn't have to be. They would use more of the urea liquid, and it would need more topping up (so, in between service intervals, for those who have been able to stretch it to scheduled VW visits, so far). This shouldn't affect fuel consumption or CO2 materially.
For the cars that use an EGR system currently, EGR would have to be used a lot more. This would be such a significant change to the calibration that they would really want to repeat much of the qualification testing (eg, environmental extremes, behaviour with poor quality fuel...even electromagnetic compatibility) but they'll probably find excuses not to do everything while taking long enough to actually do it.
This will affect CO2, potentially,, and fuel consumption (and, even if it didn't, there will be howls of pain from drivers who claim that it does, even if they have only been taking any serious notice of consumption since the scandal broke). I'd estimate the potential fuel consumption impact at a bit more than your 1%, but still not gross.
Biting the hand that feeds IT
