Particle effective density and mass during steady-state operation of GDI, PFI, and diesel passenger cars

Quiros, David; Hu, Shaohua; Hu, Shishan; Lee, Eon S.; Sardar, Satya; Wang, Xiaoliang; Olfert, Jason S.; Jung, Heejung; Zhu, Yifang; Huai, Tao

doi:10.1016/j.jaerosci.2014.12.004

Cited by 66 publications

(57 citation statements)

References 48 publications

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“…The measurements on the PFI vehicle was conducted in the CARB Haagen-Smit Laboratory (HSL) located in El Monte, CA. Details regarding the HSL setup and configuration for the light-duty testing laboratory can be found in Hu et al (2014) and Quiros et al (2015a). Table 1 lists the six testing configurations and specifications evaluated in this study.…”

Section: Laboratory Setupmentioning

confidence: 99%

“…Vehicles were operated on a chassis dynamometer, and the diesel generator was used with a resistive load bank (Swift-E STD, Simplex Inc.) to ensure a consistent power output. The vehicles and generator were operated for 30 min prior to taking measurements to ensure thermal stability of engine Quiros et al (2015a) for full description. **Estimated mass-mobility scaling exponent based on the findings reported in Quiros et al (2015a).…”

Section: Laboratory Setupmentioning

confidence: 99%

“…One of the alternative PM measurement methods that CARB (2012) is evaluating to support the LEV III PM standards is integrated particle size distribution (IPSD) (Liu et al 2009), which estimates real-time suspended particle mass from particle size distribution (PSD) and an effective density function. Since the method does not use filter media, IPSD is unaffected by gaseous adsorption artifact or particle evaporation after collection onto filters, and therefore has been explored to evaluate whether the method offers greater sensitivity for measuring PM mass at low emission levels (Liu et al 2009;Li et al 2014;Quiros et al 2015a). Furthermore, measuring PSD provides not only the ability to estimate PM mass but also other important characteristics of vehicle particle emissions such as total particle number and surface area.…”

Section: Introductionmentioning

confidence: 99%

“…In a unipolar charging environment, aggregates of fractal morphology carry more charge than near spherical particles of equivalent mobility diameter (Chang 1981) by 20-30% as shown experimentally by Shin et al (2010) and Oh et al (2004). Although some studies have proposed and demonstrated corrections for size distributions measured by the default matrix (Zimmerman et al 2015;Quiros et al 2014Quiros et al , 2015a, there is continued interest in deriving accurate size distributions directly from the instrument following.…”

Section: Introductionmentioning

confidence: 99%

“…Emission sources were a diesel generator, a light-duty gasoline direct injection (GDI) vehicle, a conventional light-duty gasoline port fuel injection (PFI) vehicle, and a light-duty diesel (LDD) vehicle equipped with a diesel particulate filter (DPF). This selection of emission sources provides a broad spectrum of vehicle particulate from gasoline and diesel sources without wall-flow particulate aftertreatment (D m D 2.2-2.7), as well as particulate downstream of a DPF (D m D 2.3-3.0) as discussed by Quiros et al (2015a) to challenge the new soot matrix. This study evaluates the performance of the EEPS soot matrix using total particle number concentration, suspended particle mass determined by the IPSD method, and lognormal fitting statistics to either a unimodal or bimodal distribution (geometric mean diameter [GMD], geometric standard deviation [GSD], and area under the curve.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Vehicle Exhaust Particle Size Distributions Measured by SMPS and EEPS During Steady-State Conditions

Xue

Wang

et al. 2015

Aerosol Science and Technology

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Fast-sizing spectrometers, such as the TSI Engine Exhaust Particle Sizer (EEPS), have been widely used to measure transient particle size distributions of vehicle exhaust. Recently, size distributions measured during different test cycles have begun to be used for calculating suspended particulate mass; however, several recent evaluations have shown some deficiencies in this approach and discrepancies relative to the gravimetric reference method. The EEPS converts electrical charge carried by particles into size distributions based on mobility classification and a specific calibration, and TSI recently released a matrix optimized for vehicle emissions as described by Wang et al. (Submitteda). This study evaluates the performance of the new matrix (soot matrix) relative to the original matrix (default matrix) and reference size distributions measured by a scanning mobility particle sizer (SMPS). Steady-state particle size distributions were generated from the following five sources to evaluate exhaust particulates with various morphologies estimated by mass-mobility scaling exponent: (1) A diesel generator operating on ultralow sulfur diesel, (2) a diesel generator operating on biodiesel, (3) a gasoline direct-injection vehicle operating at two speeds, (4) a conventional port-fuel injection gasoline vehicle, and (4) a light-duty diesel (LDD) vehicle equipped with a diesel particulate filter. Generally, the new soot matrix achieved much better agreement with the SMPS reference for particles smaller than 30 nm and larger than 100 nm, and also broadened the accumulation mode distribution that was previously too narrow using the default matrix. However, EEPS distributions still did not agree with SMPS reference measurements when challenged by a strong nucleation mode during high-load operation of the LDD vehicle. This work quantifies the range of accuracy that can be expected when measuring particle size distribution, number concentration, and integrated particle mass of vehicle emissions when using the new static calibration derived based on the properties of classical diesel soot.

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Section: Laboratory Setupmentioning

confidence: 99%

Section: Laboratory Setupmentioning

confidence: 99%