You can read in their website how it works..some use particulate filters..some use def fluid and heat..they basically made a fancy catylitic converter..that burns the soot as fast as it comes out..still smells like burnin diesel..an if you bark a turbo it will gouge a little smoke…mahindra has one model that uses def fluid..or did anyway..it was the biggest tractor they make..it is the only one tho..everything under 125hp burns constantly and does not regen. Id also like to tout how powerful these tractors are..even the small ones are eat up with it..the combined power an hydraulic lift on the 1528 i ran for 150hrs worth made me think i was gonna bust hoses left an right..yall shoulda seen the stump i turned up n lifted with that little tractor..i shoulda had my butt kicked for the abuse i put that machine through…mighty little tractor for 34hp..an i can make one do tricks..imagine what a biggin will do🤔