The effects of ash on DPF performance was reviewed in terms of the DPF ash compositions

sources

and properties

the effects of ash on DPF pressure drop behavior

filtration efficiency

and regeneration process

and the DPF ash cleaning methods. The reported studies showed that DPF ash primarily comes from the additives of the engine lubricant oil. The effects of ash on DPF pressure drop behavior vary with the changes of lubricant oil formula

ash deposition pattern

and DPF structure design. The accumulation of ash in DPF generally improves the filtration efficiency of the DPF

but it deteriorates the passive regeneration effects of the catalyzed DPF

and negatively affects the DPF active regeneration frequency as well as the filter temperature during active regeneration. Periodic ash cleaning is needed for the DPFs for heavy-duty applications

and the reverse flow pneumatic cleaning is currently the most prevalent method for DPF ash cleaning.