So, any Japanese or American companies doing this as well? Who's next?
You want low NOx emissions, you need richer mixtures, and thus higher fuel consumption and higher CO2 emissions.
Isn't that where catalytic converters come in though?
Rules in conflict surely are required by the chemistry of the situation, the companies have to search for the local minima in order to comply.
Diesel exhaust is too oxygen-rich for the cat to effectively catalyze the NOx. That's why recent passenger car diesel systems have a Diesel Exhaust Fluid system.
The Chevy Cruze Diesel was as clean as promised in the US version but the European version may not be as clean[1].
http://www.thetruthaboutcars.com/2015/09/tech-dive-chevy-cru...