Reducing PM Measurement Variability by Controlling Static Charge

Chase, Richard E.; Duszkiewicz, Gary J.; Lewis, Desmonia; Podsiadlik, Diane H.

doi:10.4271/2005-01-0193

Cited by 12 publications

(4 citation statements)

References 1 publication

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“…Below about 5 mg/km, the regulatory method for PM mass measurement faces qualitatively new challenges as effects from temperature, humidity, electrostatic charge, and gas phase adsorption become comparable to the mass collected by filter media (Chase, Duszkiewicz, Lewis, & Podsiadlik, 2005;Chase et al, 2004). Moreover, exhaust aftertreatment does not just lower emissions, it alters the chemical composition of vehicle exhaust.…”

Section: Introductionmentioning

confidence: 98%

Chemical characterization of particulate emissions from diesel engines: A review

Maricq

2007

Journal of Aerosol Science

760

122

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Section: Introductionmentioning

confidence: 98%

Chemical characterization of particulate emissions from diesel engines: A review

Maricq

2007

Journal of Aerosol Science

760

122

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“…Consequently, considerable effort is ongoing to evaluate the accuracy of filter based PM sampling at the current 3 mg/mi LEV III and Tier 3 standards and its suitability for the future LEV III level of 1 mg/mi (Hu et al 2014;Jung et al 2016Jung et al , 2017aChang and Shields 2017). The problem is twofold: Unlike metal calibration weights, the filter media used to collect PM are subject to variability from gaseous adsorption, static charge and humidity (Chase et al 2004;Chase et al 2005). The necessity of subtracting pre and post filter weights to determine the collected PM mass compounds this variability.…”

Section: Introductionmentioning

confidence: 99%

Using partial flow dilution to measure PM mass emissions from light-duty vehicles

Maricq

Peabody

Lisiecki

2017

Aerosol Science and Technology

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Partial flow dilution (PFD) offers a number of benefits relative to conventional full flow dilution tunnels for motor vehicle PM emissions measurement in terms of measurement variability, footprint, and cost. Its implementation into automotive emissions test cells depends on its ability to record PM mass emissions equivalent to the current constant volume sampling (CVS) dilution tunnel approach. The present work examines factors critical to successful application of PFD sampling and compares vehicle PM emissions measured simultaneously by PFD and CVS tunnel. The combination of a current technology commercial PFD system and ultrasonic flow meter fulfill the two principal requirements of accurate exhaust flow measurement and fast time response for proportional sampling. PM mass emissions measured by PFD versus CVS systems satisfy a 1.03 § 0.03 regression for the regulatory FTP test cycle, and comparably good agreement for the supplemental US06 drive cycle. Both dilution approaches are amenable to the single filter approach newly allowed under EPA regulations; however, the PFD sample weighted approach has the capability to provide a roughly 35% lower variability relative to the flow weighted approach used in the CVS method. Whereas partial flow dilution has seen application in heavy duty engine measurements, the present work demonstrates its feasibility for light duty chassis dynamometer testing.

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“…This method fails to address the charge located on the underside of the filter. Chase et al (2005) discussed neutralization best practices, proposed filter charging mechanisms, and recommended a device (Electrostatic Discharge Platform (EDP)) to remove most of the charge. The EDP neutralizes both sides of a filter using multiple 210 Po sources placed an appropriate distance apart.…”

Section: Introductionmentioning

confidence: 99%