Correcting mass measurement of diesel particulate filters at non-ambient temperatures

Abstract

• This is an article from the journal, Proceedings of the In- Abstract: Diesel particulate filters (DPFs) are becoming a widespread method for reducing the particulate matter (PM) emissions from both on-highway and off-highway automotive diesel engines. Mass measurements of DPFs are commonly used to determine rapidly both the amount of PM trapped by the filter and the amount regenerated (removed) by regeneration systems. To avoid issues with adsorption of atmospheric water the filters are often weighed at elevated temperatures. It is shown in this work that at elevated temperatures the filters weigh less than at lower temperatures as a direct result of the buoyant hot air within the filter substrate. This study shows that consideration of the buoyancy forces allows for correction of the mass measurement for the errors relating to the non-ambient temperature of the filter, allowing mass measurements at elevated temperatures while avoiding adsorption of atmospheric water on to the filter substrate and, therefore, improving the accuracy of mass-measurement-based studies of filtration and regeneration performance of DPFs. It is demonstrated that a filter with approximately 85 per cent overall porosity weighed at 150 uC in ambient temperatures will have an error of about 0.3 g/l (typically about 10 per cent of the trapped PM mass) in the mass measurement when not correcting for the temperature. By way of an example, this is shown to have potentially an important effect on the calculated trapped PM.

Low Power Autoselective Regeneration of Monolithic Wall Flow Diesel Particulate Filters

“…To ensure the same behaviour that would occur in practice the tests were carried out without preheating the filter samples. Where the filter was weighed at elevated temperatures after loading on an engine, buoyancy effects on the mass measurements were taken into account [17] .…”

Solid nanoparticle and gaseous emissions of a diesel engine with a diesel particulate filter and use of a high-sulphur diesel fuel and a medium-sulphur diesel fuel

“…27 For complete elimination of the sulphate condensates, the temperature must be at least 300°C. Sulphate condensates cannot be removed with the current DPF technology; 28 however, for both MSD fuel and HSD fuel, the technology was observed to be quite robust in eliminating solid particles.…”