Convex Fuel Consumption Model for Diesel and Hybrid Buses

2017 ◽  
Vol 2647 (1) ◽  
pp. 50-60 ◽  
Author(s):  
Jinghui Wang ◽  
Hesham A. Rakha
Keyword(s):  
Fuel Consumption ◽  
Motor Vehicle ◽  
Model Performance ◽  
Field Measurements ◽  
Convex Model ◽  
Motor Vehicle Emissions ◽  
Vehicle Load ◽  
Wide Range ◽  
Consumption Model ◽  
Full Throttle

The concave fuel consumption model may generate unrealistic driving recommendations in a control system; for instance, the model may recommend higher cruise speed to achieve lower fuel consumption levels on steeper roads. To improve the model performance with regard to driving control, the study developed a convex second-order polynomial fuel consumption model for conventional diesel and hybrid-electric buses. The model simultaneously circumvents the bang-bang type of control that implies that drivers would have to accelerate at full throttle or brake at full braking to minimize their fuel consumption levels. Six bus series (four diesel series and two hybrid series), covering a wide range of bus properties, were modeled. The model was developed on the basis of the Virginia Tech comprehensive power fuel-based model (VT-CPFM) framework and, given a lack of readily available data, calibrated by conducting empirical measurements. The model was validated by comparing its estimates against in-field measurements and predictions from the comprehensive modal emissions model, the Motor Vehicle Emissions Simulator model, and the concave VT-CPFM model. The results demonstrate that the convex model generates estimates consistent with field measurements and the predictions of the other models and can provide realistic driving recommendations without significantly sacrificing accuracy relative to the concave model. Optimum fuel economy cruise speed ranges from 39 to 47 km/h for all tested buses on grades ranging from 0% to 8% and decreases with the increase of grade and vehicle load.

The Aerosol Modeling Testbed: A Community Tool to Objectively Evaluate Aerosol Process Modules

2011 ◽  
Vol 92 (3) ◽  
pp. 343-360 ◽  
Author(s):  
Jerome D. Fast ◽  
William I. Gustafson ◽  
Elaine G. Chapman ◽  
Richard C. Easter ◽  
Jeremy P. Rishel ◽  
...  
Keyword(s):  
Model Performance ◽  
Field Measurements ◽  
Weather Research And Forecasting ◽  
Limited Data ◽  
Test Bed ◽  
New Approach ◽  
Aerosol Process ◽  
Wide Range ◽  
Aerosol Modeling ◽  
Current Paradigm

Abstract The current paradigm of developing and testing new aerosol process modules is haphazard and slow. Aerosol modules are often tested for short simulation periods using limited data so that their overall performance over a wide range of meteorological conditions is not thoroughly evaluated. Although several model intercomparison studies quantify the differences among aerosol modules, the range of answers provides little insight on how to best improve aerosol predictions. Understanding the true impact of an aerosol process module is also complicated by the fact that other processes—such as emissions, meteorology, and chemistry—are often treated differently. To address this issue, the authors have developed an Aerosol Modeling Testbed (AMT) with the objective of providing a new approach to test and evaluate new aerosol process modules. The AMT consists of a more modular version of the Weather Research and Forecasting model (WRF) and a suite of tools to evaluate the performance of aerosol process modules via comparison with a wide range of field measurements. Their approach systematically targets specific aerosol process modules, whereas all the other processes are treated the same. The suite of evaluation tools will streamline the process of quantifying model performance and eliminate redundant work performed among various scientists working on the same problem. Both the performance and computational expense will be quantified over time. The use of a test bed to foster collaborations among the aerosol scientific community is an important aspect of the AMT; consequently, the longterm development and use of the AMT needs to be guided by users.

Modeling Urban Bus Fuel Consumption in Shanghai, China, Based on Localized MOVES

2018 ◽  
Vol 2672 (25) ◽  
pp. 150-162 ◽  
Author(s):  
Wenjian Jia ◽  
Xiaohong Chen ◽  
Xiaonian Shan
Keyword(s):  
Energy Consumption ◽  
Fuel Consumption ◽  
Motor Vehicle ◽  
Operating Mode ◽  
Environment Protection ◽  
Extended Application ◽  
Energy Consumption Model ◽  
Urban Bus ◽  
Consumption Model ◽  
Type Classification

In China, urban bus energy consumption is an increasing concern due to system expansion and poor energy efficiency due to frequent stopping and starting by buses. This study develops a mesoscopic bus energy consumption model based on the U.S. Environment Protection Agency’s Motor Vehicle Emission Simulator (MOVES). To localize MOVES, link operating mode distribution is calculated by bus GPS data collected from nine routes in Shanghai, China. A comparison of bus fuel economy between the U.S.A. and China is conducted to determine the model years in U.S.A. and China which have similar fuel consumption performance for buses with a certain weight. After MOVES localization, link energy consumption factors are estimated, and then the impacts of average speed, vehicle stops, acceleration, and road facility on link energy consumption factors are explored. Based on this exploration of influential variables, this study develops link-level bus energy consumption factor look-up tables for a variety of bus types. Model validation indicates that using link-level indicators to estimate bus energy consumption can achieve acceptable accuracy, and that the link type classification method can influence the accuracy of the mesoscopic bus energy consumption model. This study is useful to estimate bus energy consumption when instantaneous speed data is unavailable. This study also explores the extended application of MOVES by offering a procedure for applying MOVES to develop a bus energy consumption model in regions beyond the U.S.A.

Formation and composition of training flax collection

2020 ◽  
pp. 61-71
Author(s):  
L.M. Kryvosheieva ◽  
V.I. Chuchvaha ◽  
N.M. Kandyba
Keyword(s):  
Plant Breeding ◽  
Gene Pool ◽  
Phenotypic Variability ◽  
Plant Genetic Resources ◽  
Field Measurements ◽  
Educational Process ◽  
Educational Institutions ◽  
Economic Traits ◽  
Wide Range ◽  
History Of

Aim. Based on the results of multi-year research into the flax gene pool, to form a flax training collection to provide breeding scientific organizations and educational institutions with collection samples as well as with information about the bast crop gene pool. Results and Discussion. The studies were conducted in the crop rotation fields for breeding and seed production of the Institute of Bast Crops of the NAAS (Hlukhiv, Sumska Oblast) in 1992-2018. The field measurements and laboratory analyses were carried out in accordance with conventional methods of field and laboratory studies of collection flax samples.The article presents the results on the formation of a training collection of flax at the Institute of Bast Crops of the NAAS, which has 117 accessions (11 botanical species and three varieties) from 22 countries. In addition to species diversity, the collection includes accessions with different levels of expression of valuable economic and biological characteristics. It also includes accessions selected by phenotypic variability of individual characters or their combinations. The multi-year research into the flax collection accessions resulted in identification of sources of highly-expressed valuable economic traits, which are of interest for the plant breeding course. The history of flax breeding in Ukraine is shown, where breeding varieties that are most widespread or were significant breeding achievements in solving certain problems, are presented. The collection can be used as a visual aid for the plant breeding course in educational programs; in addition, it can provide starting material for scientific and educational institutions. The collection is registered with the National Center for Plant Genetic Resources of Ukraine (certificate No. 00273 dated 04/11/2019). Conclusions. The studies of accessions from the national flax collection allowed us to build up a training collection and register it with the NCPGRU. The collection represents a wide range of biological and economic features of the gene pool of this crop. The collection can be used in the educational process of educational agricultural and biological institutions. The multi-year research into the national flax collection resulted in identification of sources of highly-expressed valuable economic traits, which are of interest to the plant breeding course. The history of flax breeding in Ukraine got covered, and breeding varieties that are most widespread or were significant breeding achievements in solving certain problems are presented.

scholarly journals Quantifying Air Pollutant Variations during COVID-19 Lockdown in a Capital City in Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 788
Author(s):  
Rong Feng ◽  
Hongmei Xu ◽  
Zexuan Wang ◽  
Yunxuan Gu ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Rural Areas ◽  
Vehicle Emissions ◽  
Motor Vehicle ◽  
Northwest China ◽  
Air Pollutant ◽  
Capital City ◽  
Air Pollution Control ◽  
Motor Vehicle Emissions

In the context of the outbreak of coronavirus disease 2019 (COVID-19), strict lockdown policies were implemented to control nonessential human activities in Xi’an, northwest China, which greatly limited the spread of the pandemic and affected air quality. Compared with pre-lockdown, the air quality index and concentrations of PM2.5, PM10, SO2, and CO during the lockdown reduced, but the reductions were not very significant. NO2 levels exhibited the largest decrease (52%) during lockdown, owing to the remarkable decreased motor vehicle emissions. The highest K+ and lowest Ca2+ concentrations in PM2.5 samples could be attributed to the increase in household biomass fuel consumption in suburbs and rural areas around Xi’an and the decrease in human physical activities in Xi’an (e.g., human travel, vehicle emissions, construction activities), respectively, during the lockdown period. Secondary chemical reactions in the atmosphere increased in the lockdown period, as evidenced by the increased O3 level (increased by 160%) and OC/EC ratios in PM2.5 (increased by 26%), compared with pre-lockdown levels. The results, based on a natural experiment in this study, can be used as a reference for studying the formation and source of air pollution in Xi’an and provide evidence for establishing future long-term air pollution control policies.

A Variable-Geometry Power Turbine for Marine Gas Turbines

1989 ◽  
Author(s):  
Karl W. Karstensen ◽  
Jesse O. Wiggins
Keyword(s):  
Fuel Consumption ◽  
Gas Turbines ◽  
Part Load ◽  
Surface Ship ◽  
Marine Propulsion ◽  
Medium Speed ◽  
Power Turbine ◽  
Wide Range ◽  
Electrical Generator ◽  
Variable Power

Gas turbines have been accepted in naval surface ship applications, and considerable effort has been made to improve their fuel consumption, particularly at part-load operation. This is an important parameter for shipboard engines because both propulsion and electrical-generator engines spend most of their lives operating at off-design power. An effective way to improve part-load efficiency of recuperated gas turbines is by using a variable power turbine nozzle. This paper discusses the successful use of variable power turbine nozzles in several applications in a family of engines developed for vehicular, industrial, and marine use. These engines incorporate a variable power turbine nozzle and primary surface recuperator to yield specific fuel consumption that rivals that of medium speed diesels. The paper concentrates on the experience with the variable nozzle, tracing its derivation from an existing fixed vane nozzle and its use across a wide range of engine sizes and applications. Emphasis is placed on its potential in marine propulsion and auxiliary gas turbines.

Impact of sulfur-in-gasoline on motor vehicle emissions in the metropolitan area of Mexico City☆

Fuel ◽  
2003 ◽  
Vol 82 (13) ◽  
pp. 1605-1612 ◽  
Author(s):  
I Schifter ◽  
L Dı́az ◽  
M Vera ◽  
E Guzmán ◽  
E López-Salinas
Keyword(s):  
Mexico City ◽  
Metropolitan Area ◽  
Vehicle Emissions ◽  
Motor Vehicle ◽  
Motor Vehicle Emissions
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