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

Czerwiński, Jan; Zimmerli, Yan; Mayer, Andreas; D’Urbano, Giovani; Zürcher, Daniel

doi:10.1007/s40825-015-0018-7

Cited by 20 publications

(10 citation statements)

References 23 publications

(35 reference statements)

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“…Urea overdosing did not further increase the concentration of particles being formed with stoichiometric dosing. This is in agreement with what Czerwinski et al (2015) observed in tests of a combined SCR DPF system. Similarly, Robinson et al (2016) reported a minor effect in regulated PN emissions when shifting from 1.1 to 1.5 ANR.…”

Section: Discussionsupporting

confidence: 92%

“…Such low concentrations should be available even at stoichiometric dosing employed owing to the finite conversion efficiencies of the SCR (90%-95% in the HDE tests) and also due to nonhomogeneous mixing of the injected urea. The assumption of gas-phase particle precursors is also supported from the marginal effect of overdosing on the distribution and concentration of the produced particles observed in the present and previous (Czerwinski et al 2015;Robinson et al 2016) studies. It would be expected that overdosing of urea would promote particle formation originating from impurities of urea decomposition.…”

Section: Discussionsupporting

confidence: 80%

“…These figures compare well to what has been reported in previous studies. Czerwinski et al (2015) investigated the effect of urea injection on a tandem DPF SCR aftertreatment system retrofitted on a 3 l Euro 4 engine. They reported that urea injection led to an increase of the nonvolatile particles below 70 nm and above 200 nm, although the effect was more dominant at the small sizes.…”

Section: Discussionmentioning

confidence: 99%

“…High numbers of volatile particles have been observed, but these volatile particles were attributed to nucleation mode formation due to the existence of a catalyst (e.g., Herner et al 2011;Lehtoranta et al 2015). Some studies showed an increase in the nonvolatile PN emissions due to secondary formation of nanoparticles in the SCR system (Czerwinski et al 2015). These particles could be nitrates and sulfates (Amanatidis et al 2014;Bao et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Mamakos

Schwelberger

Fierz³

et al. 2019

Aerosol Science and Technology

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The nonvolatile particle number (PN) emissions of late technology diesel heavy-duty vehicles (HDV) are very low due to the introduction of Diesel Particulate Filters (DPF). Nevertheless, a large fraction (50%) of particles below the current lower regulated size (23 nm) was recently reported. Moreover, large differences between laboratory and PN Portable Emission Measurement Systems (PN-PEMS) have been observed. In order to better understand such differences, the physical properties of the exhaust aerosol from two Euro VI technology diesel heavy-duty engines were studied. It was found that urea injection leads to formation of nonvolatile particles. The produced particles covered a wide size range spanning from below 10 nm to above 100 nm. As such, they contribute to the regulated PN emissions, with measured concentrations corresponding to as high as 2 Â 10 11 #/kWh over a World Harmonized Transient Cycle (WHTC). However, a large fraction of them was undetected owing to their small particle size. Low-cutoff size (10 nm) Condensation Particle Counters (CPCs) (which are under discussion to be included in the regulations) measured up to twice as high concentrations. Considering the large particle losses in the sampling systems at this size range, the true concentrations can be two times higher from what the low-cutoff CPCs reported. When the temperature of the SCR system exceeded a threshold of 300 C, the produced particles were found to be positively charged, increasing the average exhaust aerosol charge up to þ3 elementary charges per particle. Scanning Mobility Particle Sizer (SMPS) measurements of non-neutralized samples revealed that even the smallest of them can carry more than one positive charge. The findings of this study can explain the differences reported between PEMS and laboratory systems and especially those based on diffusion charging. They also provide insight for a refinement of technical requirements prescribed in the European PEMS regulation to more accurately quantify the PN emissions from such technologies.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Mamakos

Schwelberger

Fierz³

et al. 2019

Aerosol Science and Technology

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“…The size of the particles forming in the SCR is ideal for filtration on DPFs. Accordingly, combined SCR/DPF systems or after-treatment configurations employing the SCR upstream of the DPF will efficiently capture these particles [44].…”

Section: Discussionmentioning

confidence: 99%

Experimental Assessment of an Electrofilter and a Tandem Positive-Negative Corona Charger for the Measurement of Charged Nanoparticles formed in Selective Catalytic Reduction Systems

Schwelberger

Mamakos

Fierz³

et al. 2019

Applied Sciences

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Onboard measurement of non-volatile particle number (PN) emissions with portable emissions measurement systems (PEMS) was introduced for the type-approval of passenger cars in Europe since 2017 and is foreseen for heavy-duty (HD) vehicles in 2021. First studies on the performance of PN-PEMS with HD engine exhaust revealed larger differences between established PN-PEMS techniques than what was observed for passenger cars. Particles forming in selective catalytic reduction (SCR) systems for NOx of late technology HD engines have recently been identified as a potential reason for the observed differences. The formed particles have a size distribution peaking below the regulatory limit of 23 nm and most importantly acquire high (more than one) positive charges at the elevated exhaust temperatures. Precise measurement of such highly charged nanosized particles with PN-PEMS instrumentation utilizing diffusion charger (DC) based counters requires proper conditioning of these charges. Two approaches were investigated in this study: (a) an electrofilter (EF) to completely remove charged particles below the regulated size and (b) a tandem negative-positive corona (TC) charger to directly condition pre-charged particles. The two technical solutions were tested alongside the unmodified DC-based PN-PEMS, a PN-PEMS utilizing a condensation particle counter (CPC) and a reference stationary PN system using exhaust of two SCR-equipped HD engines. The results confirmed that the particles forming in such SCR systems are responsible for the observed inconsistencies and that both technical solutions efficiently address the interferences of these pre-charged nanoparticles.

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Investigations on the Impact of Urea-Dosing on Particulate Number Measurement for Heavy-Duty Applications

Noone,

Hummel,

Lehrian

et al. 2024

Proceedings

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

Cited by 20 publications

References 23 publications

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Experimental Assessment of an Electrofilter and a Tandem Positive-Negative Corona Charger for the Measurement of Charged Nanoparticles formed in Selective Catalytic Reduction Systems

Investigations on the Impact of Urea-Dosing on Particulate Number Measurement for Heavy-Duty Applications

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