Interlaboratory Cross-Check of Heavy-Duty Vehicle Chassis Dynamometers

Traver, Michael; Tennant, Christopher J.; McDaniel, T.; McConnell, Steven S.; Bailey, Brent K.; Maldonado, Hector

doi:10.4271/2002-01-2879

Cited by 21 publications

(11 citation statements)

References 3 publications

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“…For PM emissions, the differences between RAVEM results and those of specific full-flow CVS laboratories are generally between 0 and 25%, which is less than the range of differences between different full-flow CVS systems in round-robin testing. 23 Although the RAVEM shows some tendency toward under-reporting of PM emission rates, the key calculations from RAVEM samples are the PM: tracer ratios, which are based on analyses of the same filter. As discussed later in this paper, this minimizes potential bias in tracer-based estimates of in-cabin DPM tp and PM ck concentrations that might result from calculations based on concurrent measurements from different media or methods.…”

Section: Tracers Equipment and Sampling Mediamentioning

confidence: 99%

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method

Ireson¹,

Ondov

Zielińska

et al. 2011

Journal of the Air & Waste Management Association

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Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify incabin fine particulate matter (PM 2.5 ) concentrations attributable to the buses' diesel engine tailpipe (DPM tp ) and crankcase vent (PM ck ) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PM ck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin IMPLICATIONS PM 2.5 measurements in two Seattle school buses showed average concentrations of 26 and 12 g/m 3 with windows closed and open, respectively. Virtually all PM 2.5 was carbonaceous. Tracer measurements showed that bus selfpollution contributed approximately 50% of total PM 2.5 concentrations with windows closed and 15% with windows open, with over three-quarters of these contributions attributed to crankcase emissions. Maintaining ventilation in buses clearly reduces total PM 2.5 exposures and that from the buses' own emissions. The dual tracer method now offers researchers a new technique for explicit identification of single source contributions in settings with multiple sources of carbonaceous emissions. TECHNICAL PAPER INTRODUCTIONIn-vehicle exposures to vehicle-related emissions of fine particulate matter (PM 2.5 ) and other species inside vehicles have been shown to be high relative to urban outdoor environments. 1,2 Particular emphasis has been given to concentrations of diesel exhaust particulate matter (PM) inside school buses that are attributable to the buses' own exhaust. Such source attribution efforts are difficult in purely observational studies because of the presence of emissions from other vehicles, which are chemically identical to those of the bus, and the presence of chemically similar PM emitted by nonvehicular sources. A method was therefore sought that could allow definitive identification of the emissions of a single bus. Previous studies 3-8 have produced estimates of exhaust PM inside school buses that are attributable to the buses' own exhaust ranging from 0.2 to as much as 20 g/m 3 . With the exception of Ireson et al., 5 these studies inferred bus exhaust contributions from measurements of species emitted by diesel engines and other sources and did not measure the emission rates of the ...

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Section: Tracers Equipment and Sampling Mediamentioning

confidence: 99%

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method

Ireson¹,

Ondov

Zielińska

et al. 2011

Journal of the Air & Waste Management Association

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“…The variation observed is within the typical range of disagreement found among different heavy-duty full-flow CVS chassis dynamometer systems tested in round robin testing [9]. It is a fully integrated and portable system with the following included for the on-road portion of the testing: The equipment was mounted on top of the cab of the truck for the duration of the testing.…”

Section: Hardware Testedmentioning

confidence: 51%

On-road and In-Laboratory Testing to Demonstrate Effects of ULSD, B20 and B99 on a Retrofit Urea-SCR Aftertreatment System

Walkowicz¹,

Na²,

Robertson³

et al. 2009

SAE Technical Paper Series

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In order to demonstrate the performance of a retrofitted selective catalytic reduction (SCR) system while also addressing the issues associated with greater use of biodiesel, a 2005 International 9200i tractor owned by the City of Santa Monica was retrofitted with a titaniavanadia-tungsten catalyst and a urea dosing system supplied by Extengine Systems, Inc. This tractor was operated under normal service conditions within the City of Santa Monica refuse collection and transportation fleet. An on-board emissions measurement system supplied by Engine, Fuel, and Emissions Engineering, Inc., was installed on the vehicle; it measured the emissions and fuel use of the vehicle while it operated on ultra-low-sulfur diesel (ULSD), 20% biodiesel (B20), and 99% biodiesel (B99) on consecutive days. The vehicle, with a similar aftertreatment system, was then tested at the California Air Resources Board (CARB) Los Angeles Heavy-Duty Emissions Lab and tested on the Urban Dynamometer Driving Schedule (UDDS) to again assess the effects of ULSD, B20, and B99 on the performance of the urea-SCR aftertreatment system.Results from this testing showed that oxides of nitrogen (NO x ) emissions increased by 6%-12% when the blend was increased from ULSD to B20, by 16%-35% when the blend was increased from ULSD to B99, and by 26%-27% when it was increased from B20 to B99. Particulate matter (PM) emissions decreased by 37%-50% when the blend was increased from ULSD to B20, by 71%-79% when it was increased from ULSD to B99, and by 60%-63% when it was increased from B20 to B99. The SCR system reduced NO x emissions by 64%-87%, and its performance was not affected by the use of biodiesel.

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“…Traver et al [21] used reproducibility and repeatability statistics when crosschecking six different chassis dynamometer laboratories. A heavy-duty vehicle was tested at each lab over the urban dynamometer schedule and over a steady-state cycle.…”

Section: Previous Repeatability Examinationsmentioning

confidence: 99%

“…The methodology for reducing the data used unitless reproducibility and repeatability indices, h and k respectively, as defined by the American Society for Testing and Materials. The reproducibility index refers to the laboratories' "ability to measure the same value in a standard test as other labs" [21]. The repeatability index refers to a laboratory's ability to produce consistent data when compared to the performance of the other laboratories studied.…”

Section: Previous Repeatability Examinationsmentioning

confidence: 99%

Repeatability of on-road routes and a comparison of on-road routes to the federal test procedure

Radermacher¹

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Current testing methods are often unrepresentative of real world use, causing mobile source emissions inventories to be inaccurate. Emissions inventories account for emissions produced by vehicles and stationary sources for a given area. Heavy-duty vehicle data for emissions inventories are usually taken from the federal certification test. This test often does not correspond with in-use emissions. To accurately account for inuse emissions, data must be gathered from in-use testing. West Virginia University has developed a Mobile Emissions Measurement System that recorded vehicle behavior, engine behavior, and exhaust emissions behavior during in-use testing. This system was used to obtain data from numerous vehicles over specified on-road routes. A study was conducted on on-road route repeatability. A methodology for finding repeatability had to be established, and factors influencing repeatability were identified. It was found that routes and drivers significantly influenced repeatability, and that further study of a larger sample group needs to be conducted before specific conclusions could be drawn about the influences of the vehicle on repeatability. A further study was conducted on how well the on-road routes compare to the federal emissions test. Engine behavior for on road testing was binned and compared to the federal certification test. It was found that routes that contained substantial portions of urban traffic were more representative of the federal test procedure than routes with mostly freeway driving.

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Interlaboratory Cross-Check of Heavy-Duty Vehicle Chassis Dynamometers

Cited by 21 publications

References 3 publications

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method

On-road and In-Laboratory Testing to Demonstrate Effects of ULSD, B20 and B99 on a Retrofit Urea-SCR Aftertreatment System

Repeatability of on-road routes and a comparison of on-road routes to the federal test procedure

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Interlaboratory Cross-Check of Heavy-Duty Vehicle Chassis Dynamometers

Cited by 21 publications

References 3 publications

Measuring In-Cabin School Bus Tailpipe and Crankcase PM2.5: A New Dual Tracer Method

Measuring In-Cabin School Bus Tailpipe and Crankcase PM2.5: A New Dual Tracer Method

On-road and In-Laboratory Testing to Demonstrate Effects of ULSD, B20 and B99 on a Retrofit Urea-SCR Aftertreatment System

Repeatability of on-road routes and a comparison of on-road routes to the federal test procedure

Contact Info

Product

Resources

About

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method

Measuring In-Cabin School Bus Tailpipe and Crankcase PM_2.5: A New Dual Tracer Method