Originally Posted By: SonofJoe
I'd agree with Brother Weasley with one caveat...
Theoretically, if you're not burning any oil, you're not pushing any ash out in to the exhaust, so you won't ever plug your DPF (except with soot of course). I'd also agree that all engines burn some oil even if 'some' is a very small number.
However I'd contend that this small amount of oil, is more likely to be additive-free (and therefore ash-free) light base oil that's been stripped out of the crankcase by the action of hot blow-by and the re-evaporation of condensed, unburnt/partially burnt diesel fuel (as opposed to fully formulated, ash containing oil that flows upwards passed the rings or into the combustion chamber through leaking valve seals).
Burning a small amount of oil might yet be consistent with putting no ash down your exhaust pipe.
Ash constantly finds its way to DPF and it is possible to measure with certain OBD devices. I think results are provided by differential pressure sensor.
For example, using Carly for BMW I can monitor ash build up in my car.
Also, same OBD device can tell you frequency of DPF regeneration and soot level. In that way one can figure out where is bad fuel and where is good fuel since DPF regeneration frequency differs between fuel suppliers (Shell having least frequent DPF regenerations at least here in CO).
NOACK is what matters here and that is why MB 229.51 is so specific on NOACK and Ash %.
I'd agree with Brother Weasley with one caveat...
Theoretically, if you're not burning any oil, you're not pushing any ash out in to the exhaust, so you won't ever plug your DPF (except with soot of course). I'd also agree that all engines burn some oil even if 'some' is a very small number.
However I'd contend that this small amount of oil, is more likely to be additive-free (and therefore ash-free) light base oil that's been stripped out of the crankcase by the action of hot blow-by and the re-evaporation of condensed, unburnt/partially burnt diesel fuel (as opposed to fully formulated, ash containing oil that flows upwards passed the rings or into the combustion chamber through leaking valve seals).
Burning a small amount of oil might yet be consistent with putting no ash down your exhaust pipe.
Ash constantly finds its way to DPF and it is possible to measure with certain OBD devices. I think results are provided by differential pressure sensor.
For example, using Carly for BMW I can monitor ash build up in my car.
Also, same OBD device can tell you frequency of DPF regeneration and soot level. In that way one can figure out where is bad fuel and where is good fuel since DPF regeneration frequency differs between fuel suppliers (Shell having least frequent DPF regenerations at least here in CO).
NOACK is what matters here and that is why MB 229.51 is so specific on NOACK and Ash %.