The effect of inlet flow distribution on catalytic conversion efficiency

Karvounis, Evangelos; Assanis, Dennis N.

doi:10.1016/s0017-9310(05)80060-2

Cited by 32 publications

(27 citation statements)

References 4 publications

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“…Therefore, the results obtained in this study should not be adopted directly for policy decisions in other countries. Moreover, recent studies have indicated the PAH emissions from the gasoline-powered engine might also be affected by the types of lubricant (15) and catalytic converter (16). Because other types of engine, gasoline fuel, lubricant, and catalytic converter will affect PAHs emission in the engine exhaust, further studies should be conducted to extend the generality of the above findings.…”

Section: Yearmentioning

confidence: 88%

“…We identified PAHs using the selected ion monitoring (SIM) mode. The GC/mass spectrometer (MS) was calibrated with a diluted standard solution of 16 We determined PAH recovery efficiencies by spiking the filter/cartridge with solutions containing known PAH concentrations through the same experimental procedure applied to the field samples. The recovery efficiency of PAHs varied between 0.736 and 1.15 and averaged 0.859.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A Comparison on the Emission of Polycyclic Aromatic Hydrocarbons and Their Corresponding Carcinogenic Potencies from a Vehicle Engine Using Leaded and Lead-Free Gasoline

Mi¹,

Lee²,

Tsai³

et al. 2001

Environmental Health Perspectives

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The premium leaded gasoline (PLG) and two kinds of lead-free gasoline [including 92 leadfree gasoline (92-LFG) and 95 lead-free gasoline (95-LFG) so called for their octane levels] are the three major fuels currently used in Taiwan area for spark-ignition engine vehicles. Recently worldwide efforts to reduce the use of PLG are intended to lower lead emission into the atmosphere and eventually to reduce the lead level in human blood. In Taiwan, the annual PLG consumption rates decreased significantly from 2,599 × 10 6 L/year in 1994 to 944 × 10 6 L/year in 1999. On the other hand, the annual consumption rates of 92-LFG and 95-LFG increased significantly from 1,321 × 10 6 L/year and 3,485 × 10 6 L/year in 1994, to 2,136 × 10 6 L/year and 6,118 × 10 6 L/year in 1999, respectively (Table 1). As a result, one-ring aromatic hydrocarbon in LFG fuels were added to maintain the knock resistance of vehicle engine (1). An important question, therefore, is whether the use of LFG in replacing PLG will increase emissions of some toxic substances, such as polycyclic aromatic hydrocarbons (PAHs), from gasoline-fueled engines.PAHs and their derivatives are associated with the incomplete combustion of organic material, arising partly from natural combustion, such as forest fires and volcanic eruptions; but most emissions arise from anthropogenic activities, such as the burning of gasoline in motor vehicles (2-4). For gasoline-powered engines, the emission of PAHs occurs through many factors, including the chemical compositions of the fuels, the types of lubricant and fuel additives, and the engine's operating conditions (1,5-7). However, the emission of PAHs in the above studies was assessed on the basis of total PAH concentration, without taking the carcinogenic potency of each individual PAH compound into account. To date, the International Agency for Research on Cancer (IARC) has classified several PAH compounds into probable (2A) or possible (2B) human carcinogens (8). In principle, the carcinogenic potency of a given PAH compound can be assessed based on its benzo[a]pyrene equivalent concentration (BaP eq ). Calculation of BaP eq concentration for a given PAH compound requires the use of its toxic equivalent factor (TEF)-which represents the relative carcinogenic potency of the given PAH compound by reference to the specific compound BaP-to adjust its original concentration. To date, only a few proposals for TEFs are available (9-11). Among them, the list of TEFs completed by Nisbet and LaGoy in 1992 (11) ( Table 2) reflects well the actual state of knowledge on the toxic potency of each individual PAH compound (12). On the basis of this TEFs list, the carcinogenic potency of total PAHs can be assessed by the sum of the BaP eq concentrations estimated for each PAH compound in total PAHs.In this study we aimed first to assess the effect on PAH emissions when different types of LFG replaced PLG in a test gasoline-powered engine. Assuming that PAH compositions in the engine exhaust might be affected by the types of gasoline fue...

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Section: Yearmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

A Comparison on the Emission of Polycyclic Aromatic Hydrocarbons and Their Corresponding Carcinogenic Potencies from a Vehicle Engine Using Leaded and Lead-Free Gasoline

Mi¹,

Lee²,

Tsai³

et al. 2001

Environmental Health Perspectives

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“…The turbulent flows in the exhaust pipe and in the diffuser were modeled by the k-e model. In the narrow monolith channels the flow becomes laminar, and the monolith was modeled as a porous body, a method outlined by Karvounis and Assanis [1]. The flow was assumed to be isothermal, incompressible, steady, three-dimensional and axi-symmetrical.…”

Section: Simulationsmentioning

confidence: 99%

“…The separation of flow near the wall of the diffuser causes the velocity to be lower in the outer channels of the monolith. The flow real-distribution has been shown to increase with increasing diffuser angle (0) and increasing flow rate [1,2]. Furthermore, it has been demonstrated that the flow distribution becomes more uniform when the pressure drop over the monolith is increased, for instance by a reduced channel diameter or by using a longer monolith [1,2].…”

Section: Introductionmentioning

confidence: 99%

Improved flow distribution in automotive monolithic converters

Holmgren

Grönstedt

Andersson

1997

React Kinet Catal Lett

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“…Flow uniformity was increased by utilizing higher cell density monoliths with smaller hydraulic diameter and by splitting the monolith into two parts separated by a gap [8][9][10][11]. Lower flow uniformity was observed in 3D steady state and transient numerical simulations in systems with higher monolith-to-inlet diameter ratios [12,13].…”

Section: Introductionmentioning

confidence: 99%

Understanding Flow through Catalytic Converters

Ibrahim¹,

Abdou²,

Ahmed³

2017

Proceedings of the 4th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'17)

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-In this experiment the fluid flow behaviour through an automotive catalytic converter has been studied empirically and computationally. A CFD model utilizing the k-ω turbulence model and porous media approach was developed to simulate the flow through the monolithic ceramic substrate. The flow properties for the ceramic monolith were obtained using a 3D single channel approach. CFD analysis was validated by flow experiments with non-reacting flow using high temperature air. The local velocity and temperature profiles for inlet Reynolds Number of 43,000 were measured using hot-wire and high sensitivity thermocouple sensors. The CFD results were found to predict the experimental measurements with an average root mean square error of ±8%. The present analysis is considered to be a key step towards understanding the flow behaviour through catalytic converters that can help in achieving better design of the exhaust system.

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The effect of inlet flow distribution on catalytic conversion efficiency

Cited by 32 publications

References 4 publications

A Comparison on the Emission of Polycyclic Aromatic Hydrocarbons and Their Corresponding Carcinogenic Potencies from a Vehicle Engine Using Leaded and Lead-Free Gasoline

A Comparison on the Emission of Polycyclic Aromatic Hydrocarbons and Their Corresponding Carcinogenic Potencies from a Vehicle Engine Using Leaded and Lead-Free Gasoline

Improved flow distribution in automotive monolithic converters

Understanding Flow through Catalytic Converters

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