Diesel Emission with DPF+SCR in VERTdePN - Testing & amp; Potentials

Abstract

The most efficient way and the best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NO x) are combined exhaust gas aftertreatment systems (DPF+SCR). SCR (selective catalytic reduction) is regarded as the most efficient deNO x-system, diesel particle filters are most efficient for soot abatement. Today, several suppliers offer combined systems for retrofitting of HD vehicles. The presented results are part of the work in the international network project VERT *) dePN (de-activation, decontamination, disposal of particles and NO x), which has the objectives to establish test procedures and quality standards and to introduce the SCR-, or combined DPF+SCR-systems in the VERT verification procedure. Examples of results for some of the investigated systems are given and the most important findings are:

Emission Reduction with Diesel Particle Filter with SCR Coating (SDPF)

“…Absence of DOC upstream of SDPF deteriorates strongly the deNO x efficiency due to the lack of NO 2 , but also strongly increases the NH 3 concentrations (more than double). Since there is little availability of NO 2 and consequently less reactivity of urea, there is a slight increase of secondary (nitric) nanoparticles [28][29][30].…”

VERTdePN Quality Test Procedures of DPF+SCR Systems

“…Following most important indings from VERTdePN activities, which were published in [15] and [16] are:…”

“…For basic research of SCR-systems a 6-pts test at constant engine speed was used, Fig. 3, [16], this enabled the representation of results in function of exhaust gas temperature.…”

Exhaust nanoparticle emissions from internal combustion engines: A review

“…Heavy-duty diesel engine advancements are primarily aimed at improving fuel economy, reliability, cost, and durability. Continued concern about exhaust emissions from heavyduty diesel engines, such as the PM and NOx components, has led to the implementation of progressively tighter regulations in the European Union (Brück et al, 2009;Czerwinski et al, 2011;Heywood and Welling, 2009;Johnson, 2011;Theis et al, 2011). Figure 21 shows the medium and heavy-duty DPF-SCR system that is used to meet Euro 6 emissions regulations.…”

“…As significant reduction of mobile source air toxic (MSAT) emissions has been achieved by the installation of a three-way catalyst (TWC) in a spark ignition engine (Cho et al, 2011;Hassaneen et al, 2009;Kwak et al, 2007;Peckham et al, 2011a;Samuel et al,;Takeda et al, 1995) as well as a diesel particulate filter (DPF) and a deNOx catalyst in common rail direct injection (CRDI) engines (Andrew et al, 2009;Austin et al, 2010;Brück et al, 2009;Czerwinski et al, 2011;Di-Penta et al, 2011;Paule et al, 2011). The introduction of higher fuel injection pressures, resulting in smaller fuel droplets, in combination with an improved engine control strategy and a DPF has greatly reduced particulate emissions from diesel engines, whereas gasoline direct injection (GDI) engines produce considerably more particles than conventional port fuel injection (PFI) ones (Basshuysen, 2009;Eastwood, 2008;Peckham et al, 2011b;Sabathil et al, 2011;Zhao, 1999).…”