by NowForThe5th on Thu Jul 27, 2017 12:08 pm
In theory, yes. But the EGR and DPF systems are there to control two distinctly different things - oxides of nitrogen in the former case and soot or particulate matter in the latter. These emissions are produced, at their respective peaks, under completely different conditions, so limiting one may not have a huge effect on the other.
For example, very high NOx rates are produced at idle and light load when there is minimal fuel being injected and consequently, an excess of air, or more correctly, oxygen. The EGR system defeats this by sending back some oxygen depleted gas drawn from the exhaust. In these conditions, though, the AFR will be at its highest, i.e. the engine will be running lean and particulate matter production relatively low.
Conversely, at high load there will be much less air in the mix, less NOx produced but more soot. The EGR doesn't operate, either at all or at much lower levels, under these conditions.
So, limiting the AFR isn't really going to have such a big impact on buildup in the intake system. In the petrol world AFRs are quite important but, for diesels, with their ability to dynamically change, this isn't always the case. Maintaining that magical 14.7:1 ratio isn't imperative and the engine ECU generally does a pretty good job of managing things, including periodic self cleaning of the DPF in the 'burn' function.
Your secondary fuel filter will help to keep the injectors clean and operating at efficiency while the catch can is a good thing to keep the intake system dry and clean.
As for economy, these things weigh 2 tonnes plus and are well capable of sub 8l/100km. What do you want?
Chris
If work is so terrific, why do they have to pay us to do it?