Chassis Dynamometer Study of Emissions from 21 In-Use Heavy-Duty Diesel Vehicles

Yanowitz, Janet; Graboski, Michael S.; Ryan, Lisa B.A.; Alleman, Teresa L.; McCormick, Robert L.

doi:10.1021/es980458p

Cited by 63 publications

(59 citation statements)

References 18 publications

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“…It is well known that the choice of driving cycle can impact emissions. The study detailed in Chapter 2 found that in general, g/mile emissions levels for regulated pollutants were highest for the CBD cycle, followed by the HDT cycle and the lowest emissions were generated during the WVT cycle (82). For NO x this can be seen in Figure 3 The correlation between CO and PM suggests that CO emissions would also have increased significantly with the increase in inertial weight.…”

Section: Resultsmentioning

confidence: 93%

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In-Use Emissions from Heavy-Duty Diesel Vehicles

Yanowitz

McCormick

Graboski

2000

Environ. Sci. Technol.

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209

197

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This is a three part thesis regarding the regulated emissions from in-use heavy duty diesel vehicles. The first part of the thesis involves the collection and analysis of emissions from 21 vehicles. Emissions of particulate matter (PM), nitrogen oxides (NO x ), carbon monoxide (CO), total hydrocarbon (THC) and PM sulfate fraction were measured as well as smoke opacity. The vehicles were tested on three different driving cycles. This study found that when emissions were converted to a g/gallon basis, the effect of driving cycle was eliminated for NO x and reduced for PM. Sulfate comprised less than 1% of the emitted PM. Smoke opacity was not well correlated with mass emissions of any of the regulated pollutants. Multivariate regression analysis indicated that in-use NO x emissions did not decrease for this fleet during the years 1986 to 1995 while engine certification standards dropped sharply during that time. A review of all inuse emissions data in the scientific literature supported this result. The review also showed that PM emissions were widely variable among vehicles certified under identical standards. The variability was attributed to environmental factors, inertial weight, test cycle, driver variability and vehicle condition, but the relative importance of these factors could not be determined based on previously collected data. The wide variability in PM emissions within model years and the uniformity of NOx results despite the change in engine standards showed that engine certification was not an accurate tool to predict and iv control emissions from vehicles. To better understand the relationship between engine and chassis test results, a computer model was developed that estimates engine speed and load from vehicle speed. Using this model it was possible to detect the use of electronic controls which operate the engine in a different mode during engine testing and other more typical types of operation. The model also showed that the engine certification test generated consistently less PM than the vehicle tests when the model was used to put the engine and chassis emissions on a consistent basis. A good correlation was found between rate of HP increase integrated over the test cycle and PM emissions for both the chassis and engine tests. The engine test procedure includes engine behaviors that cannot be duplicated in in-use operation, and appears to favor lower rates of acceleration than typical chassis operation. The model also showed how small changes in vehicle speeds (+/-2 mph) due to driver variability can lead to a doubling of load on the engine.v

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Section: Resultsmentioning

confidence: 93%

“…Included in this thesis are three papers, two of which have been previously published (6,7) and the third (8) which has recently been submitted for publication. An error, regarding the rate of decline in the PM regulatory standard in the first paper (Chapter 2) was corrected, and several figures were added to the third paper (Chapter 4) for completeness.…”

mentioning

confidence: 99%

In-Use Emissions from Heavy-Duty Diesel Vehicles

Yanowitz

McCormick

Graboski

2000

Environ. Sci. Technol.

Self Cite

209

197

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“…27 Tunnel measurements show NRPM 2.5 (NRPM Յ 2.5 m m in size) EF m for trucks of 0.5 g/kg fuel. 17 In comparable dynamometer studies, NRPM 2.5 EF m from trucks range from 0.4 to 0.9 g/kg fuel 49,50 and NRPM 2.5 EF m from buses range from 0.3 to 0.6 g/kg fuel. 51 The conversion factors and assumptions used to convert between the various EF units measured in these studies are described in the paper by Canagaratna and co-workers.…”

Section: Results and Discussion Vehicle Emission Measurements Near Thmentioning

confidence: 94%

Evolution of Vehicle Exhaust Particles in the Atmosphere

Canagaratna

Onasch

Wood

et al. 2010

Journal of the Air & Waste Management Association

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Aerosol mass spectrometer (AMS) measurements are used to characterize the evolution of exhaust particulate matter (PM) properties near and downwind of vehicle sources. The AMS provides time-resolved chemically speciated mass loadings and mass-weighted size distributions of nonrefractory PM smaller than 1 m (NRPM 1 ). Source measurements of aircraft PM show that black carbon particles inhibit nucleation by serving as condensation sinks for the volatile and semi-volatile exhaust gases. Realworld source measurements of ground vehicle PM are obtained by deploying an AMS aboard a mobile laboratory. Characteristic features of the exhaust PM chemical composition and size distribution are discussed. PM mass and number concentrations are used with abovebackground gas-phase carbon dioxide (CO 2 ) concentrations to calculate on-road emission factors for individual vehicles. Highly variable ratios between particle number and mass concentrations are observed for individual vehicles. NRPM 1 mass emission factors measured for onroad diesel vehicles are approximately 50% lower than those from dynamometer studies. Factor analysis of AMS data (FA-AMS) is applied for the first time to map variations in exhaust PM mass downwind of a highway. In this study, above-background vehicle PM concentrations are highest close to the highway and decrease by a factor of 2 by 200 m away from the highway. Comparison with the gas-phase CO 2 concentrations indicates that these vehicle PM mass gradients are largely driven by dilution. Secondary aerosol species do not show a similar gradient in absolute mass concentrations; thus, their relative contribution to total ambient PM mass concentrations increases as a function of distance from the highway. FA-AMS of single particle and ensemble data at an urban receptor site shows that condensation of these secondary aerosol species onto vehicle exhaust particles results in spatial and temporal evolution of the size and composition of vehicle exhaust PM on urban and regional scales.

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“…These include measurement techniques using chassis dynamometer studies (Whitfield et al, 1998;Yanowitz et al, 1999), traffic tunnel integration studies (Kirchstetter et al, 1999), cross-road remote-sensing studies at tunnels and other fixed sites (Bishop et al, 1989;Jiménez et al, 2000;Schifler et al, 2005), and Portable Emission Measurement System (PEMS) methods (Cadle et al, 2002). Real-world driving emissions measurement techniques may differ from dynamometer based testing techniques in several ways.…”

Section: Introductionmentioning

confidence: 99%

Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

et al. 2006

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Abstract.A mobile laboratory was used to measure onroad vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NO x and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NO x , NO y , NH 3 , H 2 CO, CH 3 CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles in the form of frequency distributions as well as estimates for the fleet averaged emissions. Our measurements of emission ratios for both CNG and gasoline powered "colectivos" (public transportation buses that are intensively used in the MCMA) indicate that -in a mole per mole basis -have significantly larger NO x and aldehydes emissions ratios as compared to other sampled vehicles in the MCMA. Similarly, ratios of selected VOCs and NO y showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in U.S. cities. We estimate NO x emissions as 100 600±29 200 metric tons per year for light duty gasoline vehicles in the Correspondence to: M. Zavala (miguelz@mit.edu) MCMA for 2003. According to these results, annual NO x emissions estimated in the emissions inventory for this category are within the range of our estimated NO x annual emissions. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

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Chassis Dynamometer Study of Emissions from 21 In-Use Heavy-Duty Diesel Vehicles

Cited by 63 publications

References 18 publications

In-Use Emissions from Heavy-Duty Diesel Vehicles

In-Use Emissions from Heavy-Duty Diesel Vehicles

Evolution of Vehicle Exhaust Particles in the Atmosphere

Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

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