Geospatial Variation of Real-World Tailpipe Emission Rates for Light-Duty Gasoline Vehicles

2020 ◽  
Vol 54 (14) ◽  
pp. 8968-8979
Author(s):  
Tanzila Khan ◽  
H. Christopher Frey ◽  
Nikhil Rastogi ◽  
Tongchuan Wei
Keyword(s):  
Real World ◽  
Emission Rates ◽  
Light Duty ◽  
Gasoline Vehicles

Evaluation of the Precision and Accuracy of Cycle-Average Light Duty Gasoline Vehicles Tailpipe Emission Rates Predicted by Modal Models

2020 ◽  
Vol 2674 (7) ◽  
pp. 566-584
Author(s):  
Tongchuan Wei ◽  
H. Christopher Frey
Keyword(s):  
Goodness Of Fit ◽  
Motor Vehicle ◽  
Vehicle Group ◽  
Specific Power ◽  
Emission Measurement ◽  
Emission Rates ◽  
Light Duty ◽  
Wide Range ◽  
Gasoline Vehicles ◽  
Precision And Accuracy

A vehicle specific power (VSP) modal model and the MOtor Vehicle Emission Simulator (MOVES) Operating Mode (OpMode) model have been used to evaluate and quantify the fuel use and emission rates (FUERs) for on-road vehicles. These models bin second-by-second FUERs based on factors such as VSP, speed, and others. The validity of binning approaches depends on their precision and accuracy in predicting variability in cycle-average emission rates (CAERs). The objective is to quantify the precision and accuracy of the two modeling methods. Since 2008, North Carolina State University has used portable emission measurement systems to measure tailpipe emission rates for 214 light duty gasoline vehicles on 1,677 driving cycles, including 839 outbound cycles and 838 inbound cycles on the same routes. These vehicles represent a wide range of characteristics and emission standards. For each vehicle, the models were calibrated based on outbound cycles and were validated based on inbound cycles. The goodness-of-fit of the calibrated models was assessed using linear least squares regression without intercept between model-predicted versus empirical CAERs for individual vehicles. Based on model calibration and validation, the coefficients of determination ( R2) typically range from 0.60 to 0.97 depending on the vehicle group and pollutant, indicating moderate to high precision, with precision typically higher for higher-emitting vehicle groups. The slopes of parity plots for each vehicle group and all vehicles typically range from 0.90 to 1.10, indicating good accuracy. The two modeling approaches are similar to each other at the microscopic and macroscopic levels.

scholarly journals Particle Mass Emission Rates from Current-Technology, Light-Duty Gasoline Vehicles

2000 ◽  
Vol 50 (6) ◽  
pp. 930-935 ◽  
Author(s):  
Richard E. Chase ◽  
Gary J. Duszkiewicz ◽  
Trescott E. Jensen ◽  
Desmonia Lewis ◽  
E. John Schlaps ◽  
...  
Keyword(s):  
Particle Mass ◽  
Emission Rates ◽  
Current Technology ◽  
Light Duty ◽  
Gasoline Vehicles

Real-World Freeway and Ramp Activity and Emissions for Light-Duty Gasoline Vehicles

2017 ◽  
Vol 2627 (1) ◽  
pp. 17-25 ◽  
Author(s):  
H. Christopher Frey ◽  
Maryam Delavarrafiee ◽  
Sanjam Singh
Keyword(s):  
Study Design ◽  
Real World ◽  
Time Of Day ◽  
Specific Power ◽  
Peak Time ◽  
Oxides Of Nitrogen ◽  
Design Quality ◽  
Light Duty ◽  
Gasoline Vehicles ◽  
Vehicle Activity

There are few data on differences in real-world emissions by in-use vehicles when they operate on freeway ramps compared with operations on the freeway itself. The objective of this paper is to quantify the variability in link-based emissions rates for on-ramps and off-ramps in comparison to rates on freeways. Real-world measurements were made with the use of a portable emissions measurement system (PEMS) for selected vehicles, ramps, and freeway segments. The methodology included development of a study design for field data collection of vehicle activity and emissions, execution of the study design, quality assurance of the raw data, and analysis of the quality-assured data. Four light-duty gasoline vehicles were driven on two routes, each composed of on-ramp, freeway, and off-ramp links. Data were collected for morning peak, evening peak, and off-peak time periods. A PEMS test was used to measure exhaust emissions of oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO). The emissions rates for on-ramps were shown to be substantially higher than rates on freeways for NOx, HC, and CO. Some of this variability in emissions rates can be explained by link average vehicle specific power, which can vary by time of day and from one location to another. The variability in emissions rates by route and time of day indicates that there can be complex interactions between traffic flow, road geometry, and emissions rates. Recommendations are offered for additional study and regarding how these results can be used by researchers and practitioners.

Evaluating real-world emissions of light-duty gasoline vehicles with deactivated three-way catalyst converters

2018 ◽  
Vol 9 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Xuan Zheng ◽  
Ye Wu ◽  
Shaojun Zhang ◽  
Liqiang He ◽  
Jiming Hao
Keyword(s):  
Real World ◽  
Light Duty ◽  
Gasoline Vehicles ◽  
Three Way Catalyst

Effect of Air-Conditioning on Light Duty Gasoline Vehicles Fuel Economy

2019 ◽  
Vol 2673 (5) ◽  
pp. 131-141 ◽  
Author(s):  
Tanzila Khan ◽  
H. Christopher Frey
Keyword(s):  
Fuel Economy ◽  
Real World ◽  
Air Conditioning ◽  
Energy Use ◽  
Motor Vehicle ◽  
The Real ◽  
Light Duty ◽  
Wide Range ◽  
Gasoline Vehicles ◽  
Few Data

With more stringent U.S. fuel economy (FE) standards, the effect of auxiliary devices such as air-conditioning (AC) have received increased attention. AC is the largest auxiliary engine load for light duty gasoline vehicles (LDGVs). However, there are few data regarding the effect of AC operation on FE for LDGVs based on real-world measurements, especially for recent model year vehicles. The Motor Vehicle Emission Simulator (MOVES) is a regulatory model for estimating on-road vehicle energy-use and emissions. MOVES adjusts vehicle energy-use rates for AC effects. However, MOVES-predicted FE with AC has not been evaluated based on empirical measurements. The research objectives are to quantify the LDGVs FE penalty from AC and assess the accuracy of MOVES2014a-predicted FE with AC. The AC effect on real-world fleet-average FE was quantified based on 78 AC-off vehicles versus 55 AC-on vehicles, measured with onboard instruments on defined study routes. MOVES2014a-based FE penalty from AC was evaluated based on real-world estimates and chassis dynamometer-based FE test results used for FE ratings. The real-world FE penalty ranges between 1.3% and 7.5% among a wide range of driving cycles. Fuel consumption at idle is 13% higher with AC on. MOVES underestimates the real-world FE with AC by 6%, on average. MOVES overestimates the AC effect on cycle-average FE ranging between 13.5% and 18.5% for real-world and MOVES default cycles, and between 11.1% and 14.5% for standard cycles.

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