Characterization of Particles from a Current Technology Heavy-Duty Diesel Engine

Abstract

The physical properties, chemical properties, and morphology of particles from a current technology diesel engine run under steady-state conditions were determined during five campaigns across three calendar years. Concentrations of particulate matter, NO x , HC, CO, and CO 2 measured at a fixed sampling position were found to be repeatable between different campaigns. However, particle size distributions and number concentrations were significantly affected by dilution conditions. Particle density, estimated using a volume size distribution estimated from an ELPI together with measured mass, was found to be below 1 g/cm 3 at nonzero loads, but this is explained by an overestimation of volume by the ELPI due to particle fractal properties. Particle phase SO 4 2-, NO 3 -, PAH, organic carbon, and elemental carbon were found to vary with engine operating modes. Particles emitted from a modern diesel engine had similar cluster structures to those from old engines but consisted of smaller basic particles when analyzed with a TEM. A semivolatile liquid fraction was not normally visible in the TEM but was seen when trapped within a folded carbon film. Very fine (<10 nm) single particles were observed in diluted exhaust by TEM and confirmed by SMPS.

Diurnal and seasonal variability in size-dependent atmospheric deposition fluxes of polycyclic aromatic hydrocarbons in an urban center

“…For example, particlebound PAHs freshly emitted from combustion of liquid fossil fuel are mainly distributed in the ultrafine fractions (Miguel et al, 1998;Shi et al, 2000;Phuleria et al, 2006), but unimodal size distributions of PAHs peaking at large particle sizes have been observed from rice straw and corn straw burning, which often proceeds at lower temperatures than combustion of liquid fossil fuel (Hays et al, 2005;Li et al, 2007;Zhang et al, 2011). The size distributions of PAHs in winter in Guangzhou (Figs.…”

Characterization of Roadside Fine Particulate Carbon and its Eight Fractions in Hong Kong

“…A number of articles and reports have been published regarding the contribution of traffic to OC and EC in Europe and the USA (Kerminen et al, 1997;Miguel et al, 1998;Fraser et al, 1999;Moosmüller et al, 2000;Shi et al, 2000;Kohler et al, 2001;Ruellan et al, 2001). …”

Effects of a diesel oxidation catalyst on gaseous pollutants and fine particles from an engine operating on diesel and biodiesel

“…The OC/EC varied from 9.5 to 0.9 and from 5.7 to 1.4 at 2125 and 2690 r$min -1 , respectively. Shi et al investigated the particle carbon composition at 25%, 50%, and 100% load at two constant engine speeds on a turbocharged DI engine [3]. In that study, the OC and EC in PM were determined by measuring the emissions of CO 2 produced from samples burnt in pure oxygen within a programmable furnace.…”

“…Similar behavior of OC/EC was reported by Ålander et al [4], who showed that the OC/EC of particles from a DI engine decreased with increasing Although it is difficult to compare the results of OC and EC measured by different methods, the variation of OC/EC with engine load was consistent. Shi et al suggested that dilution condition had a greater influence on the OC fraction due to condensation of semivolatile organic compounds [3]. The OC fraction in PM mostly consists of condensed volatile organic compounds which are formed during the cooling of soot.…”

“…EC is traditionally used as a marker for human exposure to diesel exhaust and OC provides a significant amount of the mutagenic and carcinogenic chemicals in the air. The emission rates of EC and OC from a diesel engine and the ratios of EC to OC can be influenced by many factors including engine load, vehicle type, fuel composition and exhaust aftertreatment [3][4][5].…”