el ▁on ▁dies el ▁partic ulate ▁filters , ▁it ▁was ▁found ▁that ▁though ▁the ▁presence ▁of ▁sod ium ▁and ▁pot ass ium ▁carbon ates ▁a ided ▁in ▁the ▁catal yt ic ▁conversion ▁of ▁ash , ▁as ▁the ▁dies el ▁particul ates ▁are ▁catal yz ed , ▁they ▁may ▁con greg ate ▁inside ▁the ▁D . P . F . ▁and ▁so ▁inter f ere ▁with ▁the ▁clear ances ▁of ▁the ▁filter . ▁This ▁may ▁cause ▁the ▁filter ▁to ▁c log ▁and ▁inter f ere ▁with ▁the ▁reg ener ation ▁process . ▁In ▁a ▁study ▁on ▁the ▁impact ▁of ▁E . G . R . ▁rates ▁with ▁bl ends ▁of ▁j ath rop a ▁b iod ies el ▁it ▁was ▁shown ▁that ▁there ▁was ▁a ▁decrease ▁in ▁fuel ▁efficiency ▁and ▁tor que ▁output ▁due ▁to ▁the ▁use ▁of ▁b iod ies el ▁on ▁a ▁dies el ▁engine ▁designed ▁with ▁an ▁E . G . R . ▁system . ▁It ▁was ▁found ▁that ▁CO ▁and ▁CO 2 ▁em issions ▁increased ▁with ▁an ▁increase ▁in ▁exhaust ▁gas ▁rec ir cul ation ▁but ▁NO x ▁levels ▁decre ased . ▁The ▁opacity ▁level ▁of ▁the ▁j ath rop a ▁bl ends ▁was ▁in ▁an ▁acceptable ▁range , ▁where ▁traditional ▁dies el ▁was ▁out ▁of ▁acceptable ▁standards . ▁It ▁was ▁shown ▁that ▁a ▁decrease ▁in ▁No x ▁em issions ▁could ▁be ▁obtained ▁with ▁an ▁E . G . R . ▁system . ▁This ▁study ▁showed ▁an ▁advantage ▁over ▁traditional ▁dies el ▁within ▁a ▁certain ▁operating ▁range ▁of ▁the ▁E