Estimation of Fuel Efficiency of Road Traffic by Characterization of Vehicle-Specific Power and Speed Based on Floating Car Data

Song, Guohua; Yu, Lei

doi:10.3141/2139-02

Cited by 82 publications

(42 citation statements)

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“…The temperature in the SCR system was determined by two factors, including the input heat generated by the engine with the exhaust entering the SCR and the output lost heat from the SCR system. Regarding the first factor, Song [33] found that the time distribution in VSP bins can well represent the fuel consumption per unit of time. According to the law of conservation of energy, the Atmosphere 2019, 10, 337 8 of 17 fuel consumption is proportional to the amount of heat generated.…”

Section: Temperature Model Developmentmentioning

confidence: 99%

A NOx Emission Model Incorporating Temperature for Heavy-Duty Diesel Vehicles with Urea-SCR Systems Based on Field Operating Modes

Wang

Song

et al. 2019

Atmosphere

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The selective catalytic reduction (SCR) is the most commonly used technique for decreasing the emissions of nitrogen oxides (NOx) from heavy-duty diesel vehicles (HDDVs). However, the same injection strategy in the SCR system shows significant variations in NOx emissions even at the same operating mode. This kind of heterogeneity poses challenges to the development of emission inventories and to the assessment of emission reductions. Existing studies indicate that these differences are related to the exhaust temperature. In this study, an emission model is established for different source types of HDDVs based on the real-time data of operating modes. Firstly, the initial NOx emission rates (ERs) model is established using the field vehicle emission data. Secondly, a temperature model of the vehicle exhaust based on the vehicle specific power (VSP) and the heat loss coefficient is established by analyzing the influencing factors of the NOx conversion efficiency. Thirdly, the models of NOx emissions and the urea consumption are developed based on the chemical reaction in the SCR system. Finally, the NOx emissions are compared with the real-world emissions and the estimations by the proposed model and the Motor Vehicle Emission Simulator (MOVES). This indicates that the relative error by the proposed method is 12.5% lower than those calculated by MOVES. The characteristics of NOx emissions under different operating modes are analyzed through the proposed model. The results indicate that the NOx conversion rate of heavy-duty diesel trucks (HDDTs) is 39.2% higher than that of urban diesel transit buses (UDTBs).Atmosphere 2019, 10, 337 2 of 17 trucks collected in 2018 using GPS), urban transit buses frequently operate at a lower speed range than heavy-duty trucks, while heavy-duty trucks run fairly smoothly at a high-speed range.Atmosphere 2019, 10, x FOR PEER REVIEW 2 of 17 heavy-duty buses and heavy-duty trucks collected in 2018 using GPS), urban transit buses frequently operate at a lower speed range than heavy-duty trucks, while heavy-duty trucks run fairly smoothly at a high-speed range. Figure 1. Field trajectories of an urban transit bus and a heavy-duty truck.The differences in operating modes for different source types of HDDVs result in the uncertainty of the emissions estimations. For the HDDVs equipped with SCR systems, the NOx emissions are affected by the temperature of the exhaust gas [8]. Even for the same operating speed or vehicle specific power (VSP), there is a significant variation in NOx emissions caused by the different exhaust gas temperatures. However, current studies about NOx emission estimations do not consider the temperature of the exhaust gas, and the emission rates are directly calculated using the field data, which leads to an inaccuracy of the emissions measurement.In order to accurately calculate NOx emissions of HDDVs, it is necessary to understand the working mechanism of the SCR system. For HDDVs, the preferred reductant is typically an aqueous solution of nontoxic urea, which is d...

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Section: Temperature Model Developmentmentioning

confidence: 99%

A NOx Emission Model Incorporating Temperature for Heavy-Duty Diesel Vehicles with Urea-SCR Systems Based on Field Operating Modes

Wang

Song

et al. 2019

Atmosphere

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“…VSP (kW/ton) is the instantaneous tractive power per unit vehicle mass, as illustrated in Equation (1), which can be derived from the instantaneous vehicle speed and acceleration [42]. Furthermore, the increased availability of floating car data (FCD) in urban transportation networks presents a unique opportunity to develop integrated vehicle emission and network control models [43].…”

Section: Vehicle Emission Model Developmentmentioning

confidence: 99%

Essential Tasks to Reduce Environmental Pollution in Urban Transportation Networks

Qiao¹,

Li²,

Yu³

2017

Environ Pollut Climate Change

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Environmental pollution in Urban Transportation NetworksIn the past decades, extensive research efforts have been made in the area of urban environment striving to improve the urban air quality and address the challenges emerged from public health and the preservation of the entire ecological system. Transportation-related emissions are the dominant source of urban air pollution, and the second largest source of carbon dioxide (CO 2 ) emissions in the United States, which emitted approximately 27 percent of total U.S. greenhouse gas (GHG) emissions in 2015 (Figure 1). Transportation has also been the fastest-growing source of GHG emissions. From the pre-industrial era (i.e., ending about 1750) to 2015, concentrations of the greenhouse gases (CO 2 , CH 4 , and N 2 O) have increased globally by 44 percent, 162 percent, and 21 percent, respectively [1].The greenhouse gas (GHG) emissions primarily come from burning fossil fuel for all modes of transportation (vehicles, ships, trains, and planes) [2]. Petroleum based fuel took over 90 percent for transportation, including gasoline and diesel fuels. Most of the transportation related GHG emissions are carbon dioxide (CO 2 ) emissions resulting from the combustion of petroleum-based fuels. More than 50 percent of transportation related GHG emissions are from passenger vehicles, lightduty trucks, sport utility vehicles, pickup trucks, and minivans. Other portions of GHG emissions are from heavy-duty trucks, commercial aircraft, ships, boats, trains, pipelines, and lubricants.In addition to GHG emissions, transposition also makes contributions to important air pollutants (68.4 percent CO, 60 percent VOCs, 49.1 percent NO x , 5.5 percent particulates and 1.3 percent SO 2 ) [3][4][5]. Moreover, NO x is not only a primary air pollutant, but also accounted for the production of free radicals in troposphere, which can promptly react with VOCs and lead to a large variety of secondary air pollutants that could be much more hazardous to the public health than the primary air pollutants in urban environments [3][4][5]. Dirty air has been linked to cancer, asthma, stroke and heart disease, among other health issues. In UK, roughly 40,000 deaths each year can be attributable to outdoor air pollution [6,7]. Curbing vehicle emissions has become an increasingly important task in urban environment. Monitoring and Strategies to Reduce Transportation EmissionsIn response to these challenges, a range of emerging technologies are adopted to reduce transportation-related emissions on urban roadway networks. Existing traffic monitoring networks enable adaptive traffic AbstractThis article reviewed the impacts of vehicle emissions in urban transportation network, the existing strategies to reduce such transportation emissions, the complexity of urban transportation environment network, and the development of vehicle emission models. The vanguard research needs are also proposed in developing emission and air quality models and simulation, and emission-oriented transportation management strat...

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“…The second approach focused on the real‐world vehicle activity data collected by on‐board devices such as global positioning system and floating cars . These vehicle activities data reflect the impacts of roadway geometric factors (grade, lane width, etc.)…”

Section: Introductionmentioning

confidence: 99%

Estimating fuel consumption and emissions based on reconstructed vehicle trajectories

Chen

Yang

Chen

2012

J of Advced Transportation

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SUMMARY Microscopic emission models are widely used in emission estimation and environment evaluation. Traditionally, microscopic traffic simulation models and probe vehicles are two sources of inputs to a microscopic emission model. However, they are not effective in reflecting all vehicles' real‐world operating conditions. Using each vehicle's spot speed data recorded by detectors, this paper provides a new method to estimate all vehicles' real‐world activities data. These data can then be used as inputs to a microscopic emission model to estimate vehicle fuel consumption and emissions. The main task is to reconstruct trajectory of each vehicle and calculate second‐by‐second speed and acceleration from the activities data. The Next Generation Simulation dataset and the Comprehensive Modal Emissions Model are used in this study to calculate and analyze the emission results for both lane‐level and link‐level. The results showed that using the proposed method for estimating vehicle fuel consumption and emissions is promising. Copyright © 2012 John Wiley & Sons, Ltd.

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Estimation of Fuel Efficiency of Road Traffic by Characterization of Vehicle-Specific Power and Speed Based on Floating Car Data

Cited by 82 publications

References 9 publications

A NOx Emission Model Incorporating Temperature for Heavy-Duty Diesel Vehicles with Urea-SCR Systems Based on Field Operating Modes

A NOx Emission Model Incorporating Temperature for Heavy-Duty Diesel Vehicles with Urea-SCR Systems Based on Field Operating Modes

Essential Tasks to Reduce Environmental Pollution in Urban Transportation Networks

Estimating fuel consumption and emissions based on reconstructed vehicle trajectories

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