Lube actually did mention the use of EGR and the fact that it creates moor sooth ... which then is filtered with the particle filter...
modern Diesel cars are currently equipped with both EGR and particle filters... try a Volkswagen Tdi engine... it has it...
http://www.vw.com/vwcom/content/objects/pdf/engines/complete_specs_TDI.pdf
OBD D, Tier I, catalytic converter, water-cooled EGR system, onboard refueling,vapor recovery (ORVR)
gouvernements in Europe recognize that , and in Holland for example , you get a tax cut if your new diesel has certain enviromental features...
for trucks in Europe , they use another system , called adBlue
don't ask me how it works, all i know it's very much appreciated, certain EU states allready give 5% discount on toll routes if a truck has it
EDIT
more..
http://www.autoalliance.org/innovation/diesel.php
also , Diesel engines get a lot more milage
and check this chart from Renault
it lists their petrol and diesel engines
http://www.sustainability.renault.com/d/d63.htm
the Diesels have less CO2 emissions than the Petrol engines
and again a better milage.
both are Euro3 standards, only some of the petrol engines are euro4, so the difference is very little, and i'm sure the next generation diesel will just as well be Euro4