Quote Originally Posted by itix View Post
Ok, I actually have insight in this issue and can thus answer this question rather well since I work with diesel ship engines on a daily basis.
NOx is created during the combustion phase of the diesel cycle and is dependent on combustion time (i.e slower engine speed equals more nox) and combustion temperature. Diesels combust at much higher temperature than petrol and it's relatively long stroke means it can't run as fast, which is why it is plagued much more by the issue of NOx than petrol engines.

You don't actually get rid of NOx by running the engine less stoichiometrically (which is when the smoke appears) so smoke doesn't mean no NOx. Smoke comes when the engine is running rich at which point you see the unburnt carbons in the exhaust. Petrol cars have the same issue with unburnt fuel and non stoichiometric running but petrol don't form the same carbon strains as diesel do so the unburnt fuel isn't visible (and therefor looks more environmental during hard acceleration or heavy load increases when it runs rich).

Diesels are also very dependent on good atomization to get good combustion or you will see the typical black smoke. If you have blown the injectors you'll notice the smoke.

EDIT: Also, I'd like to clarify my position. I don't actually neither expect nore hope for a VW exit, just some budget cuts so the racing would be a bit closer and not VW 1, 2, 3 on every single problem free rally!

Of course Ogier would still win but he'd maybe not win every rally of the season!
Very good diesel knowledge!

Regarding VW and the WRC, I think their either in it to win it, or out all together. VW doesn't do things half way in motorsport. If its WEC (the two top teams), DTM or WRC, they do it with full commitment.