Methodology for Controlling Nitrogen Oxides Emissions during Cold Start

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Navtej Singh ◽  
Brad Adelman ◽  
Joshua Manis
Keyword(s):  
Author(s):  
Zhiming Gao ◽  
Mi-Young Kim ◽  
Jae-Soon Choi ◽  
C Stuart Daw ◽  
James E Parks ◽  
...  

We present results from a computational study of the potential for using low-cost sorbent materials to trap the emissions of hydrocarbons and nitrogen oxides temporally during cold-start periods in hybrid electric vehicles and plug-in hybrid electric vehicles operating over transient driving cycles. The hydrocarbon adsorption behavior of a candidate sorbent composed of Ag-beta-zeolite was characterized in a laboratory flow reactor to estimate the kinetic parameters for a one-dimensional transient adsorber device model. This model was then implemented in the Powertrain Systems Analysis Toolkit to simulate a passive hydrocarbon adsorber device on a hybrid vehicle. The results indicate that such an adsorber can substantially reduce the hydrocarbon emissions by temporarily storing them until the three-way catalyst is sufficiently warm to remove them from the exhaust. A similar adsorber device model was simulated for nitrogen oxide control, using an initial set of conjectured kinetic parameters for transition metal oxides based on limited information in the literature. These latter simulations revealed the need to pursue additional experimental studies to characterize fully this class of sorbents. Such studies are especially relevant in the present context of rapidly evolving vehicle technology, because emission controls of this type do not involve any penalty in fuel consumption or require any change in engine operation.


Author(s):  
B. S. Soroka

The article considers the role and place of water and water vapor in combustion processes with the purpose of reduction the effluents of nitrogen oxides and carbon oxide. We have carried out the complex of theoretical and computational researches on reduction of harmful nitrogen and carbon oxides by gas fuel combustion in dependence on humidity of atmospheric air by two approaches: CFD modeling with attraction of DRM 19 chemical kinetics mechanism of combustion for 19 components along with Bowman’s mechanism used as “postprocessor” to determine the [NO] concentration; different thermodynamic models of predicting the nitrogen oxides NO formation. The numerical simulation of the transport processes for momentum, mass and heat being solved simultaneously in the united equations’ system with the chemical kinetics equations in frame of GRI methane combustion mechanism and NO formation calculated afterwards as “postprocessor” allow calculating the absolute actual [CO] and [NO] concentrations in dependence on combustion operative conditions and on design of furnace facilities. Prediction in frame of thermodynamic equilibrium state for combustion products ensures only evaluation of the relative value of [NO] concentration by wet combustion the gas with humid air regarding that in case of dry air – oxidant. We have developed the methodology and have revealed the results of numerical simulation of impact of the relative humidity of atmospheric air on harmful gases formation. Range of relative air humidity under calculations of atmospheric air under impact on [NO] and [CO] concentrations at the furnace chamber exit makes φ = 0 – 100%. The results of CFD modeling have been verified both by author’s experimental data and due comparing with the trends stated in world literature. We have carried out the complex of the experimental investigations regarding atmospheric air humidification impact on flame structure and environmental characteristics at natural gas combustion with premixed flame formation in open air. The article also proposes the methodology for evaluation of the nitrogen oxides formation in dependence on moisture content of burning mixture. The results of measurements have been used for verification the calculation data. Coincidence of relative change the NO (NOx) yield due humidification the combustion air revealed by means of CFD prediction has confirmed the qualitative and the quantitative correspondence of physical and chemical kinetics mechanisms and the CFD modeling procedures with the processes to be studied. A sharp, more than an order of reduction in NO emissions and simultaneously approximately a two-fold decrease in the CO concentration during combustion of the methane-air mixture under conditions of humidification of the combustion air to a saturation state at a temperature of 325 K.


Author(s):  
Joel Jean ◽  
Alain Fossi ◽  
Alain deChamplain ◽  
Bernard Paquet
Keyword(s):  

2017 ◽  
Vol 68 (4) ◽  
pp. 824-829
Author(s):  
Cornel Ianache ◽  
Laurentiu Predescu ◽  
Mirela Predescu ◽  
Dumitru Dumitru

The serious air pollution problem has determined public concerns, worldwide. One of the main challenges for countries all over the world is caused by the elevated levels of ground-level ozone (O3) concentrations and its anthropogenic precursors. Ploiesti city, as one of the major urban area of Romania, is facing the same situation. This research aims to investigate spatial and temporal distribution characteristics of O3 in relationship with nitrogen oxides (NOx) using statistical analysis methods. Hourly O3 and NOx measurements were collected during 2014 year in Ploiesti. The results obtained showed that the ozone spatial distribution was non-normal for each month in 2014. The diurnal cycle of ground-level ozone concentrations showed a mid-day peak, while NOx diurnal variations presented 2 daily peaks, one in the morning (7:00 a.m.) and one in the afternoon (between 5:00 and 7:00 p.m.). In addition, it was observed a distinct pattern of weekly variations for O3 and NOx. Like in many other urban areas, the results indicated the presence of the �ozone weekend effect� in Ploiesti during the 2014 year, ozone concentrations being slightly higher on weekends compared to weekdays. For the same monitoring site, the nitrogen oxides were less prevalent on Saturdays and Sundays, probably due to reducing of road traffic and other pollution-generating activities on weekends than during the week.


1993 ◽  
Author(s):  
Don Elliott ◽  
Anna Au-Yeung ◽  
Pete Peterson
Keyword(s):  

1993 ◽  
Author(s):  
Carl Swanson ◽  
Brad Mohning ◽  
Pete Peterson
Keyword(s):  

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