On the impact of DPF downsizing and cellular geometry on filtration efficiency in pre- and post-turbine placement

Serrano, José Ramón; Bermúdez, Vicente; Angiolini, Emanuele

doi:10.1016/j.jaerosci.2017.07.014

Cited by 18 publications

(7 citation statements)

References 38 publications

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“…where the term K S n represents the adsorption equilibrium constant of the reactant n according to Eq. (7). The values of the adsorption enthalpy (∆H S n ), which is defined as the adsorption to desorption activation energy difference, and the pre-exponential factor (A S n ) are detailed in Table 1.…”

Section: Adsorption Processmentioning

confidence: 99%

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Internal pore diffusion and adsorption impact on the soot oxidation in wall-flow particulate filters

Macián

Serrano

Piqueras

et al. 2019

Energy

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The automotive industry is driven its efforts to cleaner internal combustion engines. As a result, the engine has become conditioned by the exhaust aftertreatment systems. The regeneration of wall-flow particulate filters (PFs) evidences such an interaction. The PFs prevent the soot emission whereas, as a counterpart, the fuel consumption increases.Consequently, passive and active regeneration strategies are needed to clean the filter back and limit the penalty in CO 2 . In this context, modelling tools play a key role to achieve a comprehensive understanding and control of the regeneration. In this work, a regeneration model coupled to a one-dimensional compressible unsteady flow solver for PFs is presented. The importance of the main physical and chemical steps related to the soot oxidation is discussed.The influence of the diffusion of gaseous reactants inside the primary soot particles is firstly addressed. The inclusion of this step into the definition of the reaction rate provides temperature dependence to the soot specific surface. Next, the reactants adsorption is analysed. This step leads to define a surface coverage, which behave as an equivalent reaction order. It allows figuring out the influence of the gaseous reactants concentration on the reaction rate and its dependence with the temperature.

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Section: Adsorption Processmentioning

confidence: 99%

“…The accumulation of soot into the PF gives as a result the variation of the porous medium [6] and channels geometric properties [7]. The resulting increase in pressure drop leads to a non-negligible impact on the engine fuel consumption [8] and emissions [9].…”

Section: Introductionmentioning

confidence: 99%

Internal pore diffusion and adsorption impact on the soot oxidation in wall-flow particulate filters

Macián

Serrano

Piqueras

et al. 2019

Energy

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“…The gas density is also dependent on the gas pressure, but this last has minor importance in standard post-turbine PF location where its value is closer to ambient conditions. Nevertheless, it can also get importance in pre-turbine PF configurations, thus affecting the filtration velocity and the slip-flow effect [39].…”

Section: Filtrationmentioning

confidence: 99%

“…channel width and wall thickness, Eqs. (39) and (40) can be adapted to diverse monolithic channel cross sections.…”

Section: Gaseous Emission Modellingmentioning

confidence: 99%

Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications

Payri¹,

Arnau²,

Piqueras³

et al. 2018

SAE Technical Paper Series

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The increasingly restrictive legislation on pollutant emissions is involving new homologation procedures driven to be representative of real driving emissions. This context demands an update of the modelling tools leading to an accurate assessment of the engine and aftertreatment systems performance at the same time as these complex systems are understood as a single element. In addition, virtual engine models must retain the accuracy while reducing the computational effort to get closer to real-time computation. It makes them useful for pre-design and calibration but also potentially applicable to on-board diagnostics purposes. This paper responds to these requirements presenting a lumped modelling approach for the simulation of aftertreament systems. The basic principles of operation of flow-through and wall-flow monoliths are covered leading the focus to the modelling of gaseous emissions conversion efficiency and particulate matter abatement, i.e. filtration and regeneration processes. The model concept is completed with the solution of pressure drop and heat transfer processes. The lumped approach hypotheses and the solution of the governing equations for every submodel are detailed. While inertial pressure drop contributions are computed from the characteristic pressure drop coefficient, the porous medium effects in wall-flow monoliths are considered separately. Heat transfer sub-model applies a nodal approach to account for heat exchange and thermal inertia of the monolith substrate and the external canning. In wall-flow monoliths, the filtration and porous media properties are computed as a function of soot load applying a spherical packed bed approach. The soot oxidation mechanism including adsorption reactant phase is presented. Concerning gaseous emissions, the general scheme to solve the chemical species transport in the bulk gas and washcoat regions is also described. In particular, it is finally applied to the modelling of CO and HC abatement in a DOC and DPF brick. The model calibration steps against a set of steady-state in-engine experiments allowing separate certain phenomena are discussed. As a final step, the model performance is assessed against a transient test during which all modelled processes are taking place simultaneously under highly dynamic driving conditions. This test is simulated imposing different integration time-steps to demonstrate the model´s potential for real-time applications.

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“…As a result, the downsized ATS is able to keep high conversion efficiency of gaseous pollutants [20] and filtration efficiency in wall-flow particulate filters [21], but the turbocharger lag cannot be fully recovery to the traditional post-turbine ATS performance without additional measures. In addition, the difficulty of the ATS to deal with current emission limits does not enable the placement of all the ATS upstream of the turbine.…”

Section: Introductionmentioning

confidence: 99%

Influence of Pre-Turbine Small-Sized Oxidation Catalyst on Engine Performance and Emissions under Driving Conditions

et al. 2020

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The earlier activation of the catalytic converters in internal combustion engines is becoming highly challenging due to the reduction in exhaust gas temperature caused by the application of CO2 reduction technologies. In this context, the use of pre-turbine catalysts arises as a potential way to increase the conversion efficiency of the exhaust aftertreatment system. In this work, a small-sized oxidation catalyst consisting of a honeycomb thin-wall metallic substrate was placed upstream of the turbine to benefit from the higher temperature and pressure prior to the turbine expansion. The change in engine performance and emissions in comparison to the baseline configuration are analyzed under driving conditions. As an individual element, the pre-turbine catalyst contributed positively with a relevant increase in the overall CO and HC conversion efficiency. However, its placement produced secondary effects on the engine and baseline aftertreatment response. Although small-sized monoliths are advantageous to minimize the thermal inertia impact on the turbocharger lag, the catalyst cross-section is in trade-off with the additional pressure drop that the monolith causes. As a result, the higher exhaust manifold pressure in pre-turbine pre-catalyst configuration caused a fuel consumption increase higher than 3% while the engine-out CO and HC emissions did around 50%. These increments were not completely offset despite the high pre-turbine pre-catalyst conversion efficiency (>40%) because the partial abatement of the emissions in this device conditioned the performance of the close-coupled oxidation catalyst.

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On the impact of DPF downsizing and cellular geometry on filtration efficiency in pre- and post-turbine placement

Cited by 18 publications

References 38 publications

Internal pore diffusion and adsorption impact on the soot oxidation in wall-flow particulate filters

Internal pore diffusion and adsorption impact on the soot oxidation in wall-flow particulate filters

Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications

Influence of Pre-Turbine Small-Sized Oxidation Catalyst on Engine Performance and Emissions under Driving Conditions

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