scholarly journals Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

2022 ◽  
Vol 2160 (1) ◽  
pp. 012050
Author(s):  
Piqiang Tan ◽  
Junwen Yao ◽  
Chaojie Yao ◽  
Zhiyuan Hu ◽  
Diming Lou ◽  
...  
Keyword(s):  
Nitrogen Oxide ◽  
Nox Emission ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Nitrogen Oxide Emissions ◽  
Road Vehicles ◽  
The Real ◽  
Portable Emission Measurement System ◽  
Data Processing Method ◽  
Variation Trends

Abstract The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

Impact of Flame Lifting on Nitrogen Oxide Emissions From Premixed Reacting Jets in a Vitiated Crossflow

2019 ◽  
Author(s):  
M. D. Sirignano ◽  
V. Nair ◽  
D. Sunkara ◽  
B. L. Emerson ◽  
J. Seitzman ◽  
...  
Keyword(s):  
Nitrogen Oxide ◽  
Flux Ratio ◽  
Vortex Pair ◽  
Combustion Products ◽  
Dominant Factor ◽  
Bulk Temperature ◽  
Nox Emissions ◽  
Nitrogen Oxide Emissions ◽  
Combustion Region ◽  
Two Temperatures

Abstract This paper describes measurements of nitrogen oxide (NOx) emissions from reacting jets in crossflow (RJICF). Primary factors that influence RJICF NOx emissions are: jet stoichiometry, mixing between jet and crossflow before combustion, and mixing of the remainder of the crossflow with the combustion products of the secondary combustion region. The aforementioned mixing is controlled by shear layer vortices and the counter-rotating vortex pair, as well as flame lifting. The coupled effects of bulk averaged temperature rise as a result of the RJICF (ΔT), jet stoichiometry (ϕJet), and momentum flux ratio (J) present a challenge in understanding critical factors controlling NOx production as it is difficult to vary them independently. Therefore, significant attention was paid to designing a test matrix that differentiated these effects. The data reported herein were obtained from the injection of premixed ethane/air or ethane/methane/air mixtures into a vitiated crossflow at one of two temperatures (1350K and 1410K). Varying the ethane/methane ratio allowed for systematic variation of flame lifting independent of ϕjet and J. The jets contained sufficient fuel to create an adiabatic bulk temperature rises from 75K–350K, with J values from 8–40, and ϕJet values from 0.8–8.0. The reported measurements confirm that NOx emissions increase monotonically with ΔT, as discussed in literature, but also indicates that the lifting of the flame significantly impacts NOx production. Lifting itself is a function of the variables described above and was quantified with chemiluminescence imaging. In fact, flame lifting is the dominant factor influencing NOx emissions, including ΔT.

Numerical Modelling of Swirl-Stabilized Turbulent Lean Non-Premixed Flames

2018 ◽  
Vol 29 ◽  
pp. 62-66
Author(s):  
Teresa Parra ◽  
David Pastor ◽  
Ruben Pérez ◽  
José Molina
Keyword(s):  
Numerical Modelling ◽  
Numerical Simulations ◽  
Nitrogen Oxide ◽  
Flow Pattern ◽  
Nox Emissions ◽  
Nitrogen Oxide Emissions ◽  
Swirl Injectors ◽  
Air Jet ◽  
Fuel Jet ◽  
Lean Mixtures

Numerical simulations have been performed to analyze the interaction of confined coaxial high-swirl jets in both cases: isothermal and reactive flows. Besides different setups of swirl injectors have been tested to study the influence of swirl in the flames for both stoichiometric and lean mixtures. The aim was to quantify the nitrogen oxide emissions as well as the flow pattern for different swirling annular air jet and non-swirling inner fuel jet. This simple setup is widely used in burners to promote stabilized flames of lean mixtures producing ultra low NOx emissions.

scholarly journals Technical Note: A diagnostic for ozone contributions of various NO<sub>x</sub> emissions in multi-decadal chemistry-climate model simulations

2004 ◽  
Vol 4 (1) ◽  
pp. 327-342 ◽  
Author(s):  
V. Grewe
Keyword(s):  
Error Analysis ◽  
Nitrogen Oxide ◽  
Climate Model ◽  
Technical Note ◽  
Nox Emission ◽  
Nox Emissions ◽  
Model Simulations ◽  
Linear Character ◽  
Climate Simulations ◽  
Climate Model Simulations

Abstract. Nitrogen oxide (NOx=NO+NO2) emissions from various sources contribute to the ozone budget. The identification of these contributions is important, e.g.  for the assessment of emissions from traffic. The non-linear character of ozone chemistry complicates the online diagnosis during multi-decadal chemistry-climate simulations. A methodology is suggested, which is efficient enough to be incorporated in multi-decadal simulations. Eight types of NOx emissions are included in the model. For each a NOy (=all N components, except N2 and N2O) tracer and an ozone tracer is included in the model, which experience the same emissions and loss processes like the online chemistry fields. To calculate the ozone changes caused by an individual NOx emission, the assumption is made that the NOx contributions from various sources are identical to the NOy contributions. To evaluate this method each NOx emission has been increased by 5% and a detailed error analysis is given. In the regions of the main impact of individual sources the potential error of the calculated contribution is significantly smaller than the contribution. Moreover, the changes caused by an increase of the emissions of 5% were detected with a higher accuracy than the potential errror of the absolut contribution.

scholarly journals The challenge to NO<sub>x</sub> emission control for heavy-duty diesel vehicles in China

2012 ◽  
Vol 12 (7) ◽  
pp. 18565-18604 ◽  
Author(s):  
Y. Wu ◽  
S. J. Zhang ◽  
M. L. Li ◽  
Y. S. Ge ◽  
J. W. Shu ◽  
...  
Keyword(s):  
Emission Factors ◽  
Operating Conditions ◽  
Nox Emission ◽  
Effective Control ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Compliance Testing ◽  
Heavy Duty Diesel

Abstract. China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011–2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km −1) nor brake-specific (g kW h−1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3±3.3 g km−1, 12.5± 1.3 g km−1, and 11.8±2.0 g km−1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOxmitigation for the HDDV fleet in the future.

scholarly journals Lowering Nitrogen Oxide Emissions in a Coal-Powered 1000-MW Boiler

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaojuan Chen ◽  
Haiyang Zhang ◽  
Hongwu Qin
Keyword(s):  
Nitrogen Oxide ◽  
Power Plants ◽  
Historical Data ◽  
Nox Emissions ◽  
Grey Wolf ◽  
Operational Parameters ◽  
Nitrogen Oxide Emissions ◽  
Grey Wolf Optimization ◽  
Model Accuracy ◽  
Simulation Results

Burning of coal in power plants produces excessive nitrogen oxide (NOx) emissions, which endanger people’s health. Proven and effective methods are highly needed to reduce NOx emissions. This paper constructs an echo state network (ESN) model of the interaction between NOx emissions and the operational parameters in terms of real historical data. The grey wolf optimization (GWO) algorithm is employed to improve the ESN model accuracy. The operational parameters are subsequently optimized via the GWO algorithm to finally cut down the NOx emissions. The experimental results show that the ESN model of the NOx emissions is more accurate than both of the LSTM and ELM models. The simulation results show NOx emission reduction in three selected cases by 16.5%, 15.6%, and 10.2%, respectively.

Emission Characteristics of CNG/Gasoline Dual-Fuel Taxi

2014 ◽  
Vol 505-506 ◽  
pp. 365-369
Author(s):  
Fang Qian ◽  
Tie Zhu Li
Keyword(s):  
Operating Conditions ◽  
Dual Fuel ◽  
Emission Measurement ◽  
The Real ◽  
Emission Level ◽  
Portable Emission Measurement System ◽  
Driving Speed ◽  
Hc Emissions ◽  
Set Up ◽  
All Speeds

To investigate the real emission level of compressed natural gas (CNG)/gasoline dual-fuel taxis, Portable emission measurement system (PEMS) testing techniques was applied to measure instantaneous CO2, CO, NOx and HC emissions. Comparison between CNG and gasoline was set up to analyze the influence of speed and driving modes on the gas pollutants emissions under the real-world operating conditions. Results show that the average speed of the tested taxis is 27.75 km/h and the speed has a relationship with emission level. Taxi fueled with CNG emit less CO2 and CO but more NOx and HC than taxi fueled with gasoline at all speeds below 45 km/h. CO2, CO and HC emission factor from CNG taxi were lower whilst NOx were higher, NOx emission rate of CNG taxi was higher contrast to the taxi with gasoline. The emission level of CNG taxi is better than gasoline taxi when the driving speed is low.

scholarly journals The challenge to NO<sub>x</sub> emission control for heavy-duty diesel vehicles in China

2012 ◽  
Vol 12 (19) ◽  
pp. 9365-9379 ◽  
Author(s):  
Y. Wu ◽  
S. J. Zhang ◽  
M. L. Li ◽  
Y. S. Ge ◽  
J. W. Shu ◽  
...  
Keyword(s):  
Emission Factors ◽  
Operating Conditions ◽  
Nox Emission ◽  
Effective Control ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Compliance Testing ◽  
Heavy Duty Diesel

Abstract. China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011–2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km−1) nor brake-specific (g kWh−1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3 ± 3.3 g km−1, 12.5 ± 1.3 g km−1, and 11.8 ± 2.0 g km−1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOx mitigation for the HDDV fleet in the future.

Finite-rate entrainment effects on nitrogen oxide (NOx) emissions in staged combustors

2021 ◽  
Vol 230 ◽  
pp. 111434
Author(s):  
Edwin Goh ◽  
James Li ◽  
Nam Y. Kim ◽  
Tim Lieuwen ◽  
Jerry Seitzman
Keyword(s):  
Nitrogen Oxide ◽  
Nox Emissions ◽  
Finite Rate
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