brulaz wrote:
GoPackGo wrote:
Wintersun - Why would the oil be cleaner ? DEF is injected into the exhaust after it has exited the combustion process.
Tim
Think with DEF there is less or no Exhaust Gas Recycling (EGR) which causes the soot in the oil.
And DEF should increase the mileage, but since more soot is now collected in the particulate filter, that needs to be regenerated more, which reduces mileage.
It's complicated ...
Pretty much, the old non-DEF system had to balance EGR intake to account for both, NOx reduction and Particulate matter reduction. With the introduction of DEF, they no longer used the EGR system to account for NOx reduction (letting the engines actually run a little dirtier/leaner NOx wise like they used to). So the EGR system was only used to reduced particulate matter formation. Hence, less EGR intake and cleaner oil.
Offroad diesels have it better. They have a slightly laxed emissions standards (not by much), but just enough where they could dump the DPF. They still have to use DEF though to meet their emissions limits.
Bobcat DeutzCaterpillarPerkinsIt's too bad they can't quite meet the emissions for on-road vehicles. I think the most troublesome system though is the EGR because it feeds soot back into the engine. I would rather live with a DPF than an EGR system if given the choice.