Calculation of mass-weighted distribution of diesel particulate matters using primary particle density

Real-time light transmission spectroscopy (RTLTS): A real-time and in situ particle size distribution measurement for fractal-like diesel exhaust particles

“…By contrast, the particles may be considered to be very densely packed and opaque if the fractal dimension is greater than 2.0. The fractal dimensions of the particles from the same engine were confirmed to be 2.0-2.2 (Yoon et al, 2011); therefore, Fig. 5 appears to not provide an exact result for the size of the primary particles, and the bimodal shape can be explained as an effect of particle aggregation.…”

“…The variable in the transient test was the engine load, represented by brake mean effective pressures (BMEPs) of 6, 8, and 10 bar, at a fixed speed of 2500 rpm. The purpose of the transient-condition test was to measure the particle-size distribution change in the exhaust gas as the engine cycled through these three different loads over a period of 120 s. The engine test system and load conditions were as described previously (Yoon et al, 2011), with the exception that we recorded the data during changes in the engine load to investigate transient conditions. Following the start of the test, the BMEP increased by 0.2 bar s À 1 at time intervals of 21-30 s and 51-60 s. During the interval 81-90 s, the BMEP decreased at a rate of 0.4 bar s À 1 .…”

“…Drolen & Tien (1987) hypothesized that the total volume fraction dominates the optical properties. In our previous research, (Park, Yoon, Song & Chun 2010;Yoon et al, 2011), the LII technique was applied to measure the monomer size of diesel soot using an approach similar to Drolen & Tien (1987). The effect of the particle shape can vary depending on the optical properties, and particular phenomena may arise from the measurement target and light source.…”

Development of a Real-Time,In-SituParticle Sizing Technique: Real-Time Light Transmission Spectroscopy (RTLTS)

“…However, these methods are unable to measure the number-weighted distribution of the particle directly. Additionally, these techniques can be expensive and complicated; for example, LII and LEM require additional quantification conversion, and DLS requires elaborate dilution (Park et al 2010;Yoon et al 2011). Some particle measurement techniques using light extinction spectrum can be used to measure the numberweighted distribution of particles without additional quantification procedures (Jones et al 1994;Wang and Hallett 1996;Ferri et al 1997;Müller et al 1999).…”

“…Moreover, diesel particulate regulations have changed from a mass basis to a number concentration basis because of the harmful nature of nanoparticles (Kittelson 1998;Kasper 2008). There has been significant interest in developing real-time measurement techniques that measure particulate matter in exhaust because these emissions have been shown to be sensitive to engine operating conditions (Witze et al 2004;Wei and Rooney 2010;Johnson 2011;Yoon et al 2011).…”