A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

Olowojebutu, Seun; Steffen, Thomas

doi:10.4271/2017-01-0976

Cited by 16 publications

(4 citation statements)

References 63 publications

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“…The integrated system could have a compact and low weight/volume ratio and could provide improvement in the diesel engine cold start emission performance. The modeling of the integrated unit is very difficult, since the developed model must be able to successfully include the competition of soot oxidation and SCR reaction for available NO 2 , the interaction of washcoat loading on deNOx performance, PM filtration efficiency, and system pressure drop [95]. Trandafilović et al studied the effect of soot loading on a Cu/SSZ-13 zeolite in standard SCR, NH 3 oxidation, NH 3 TPD, and soot oxidation [96].…”

Section: Other Simulation Approachesmentioning

confidence: 99%

Most Recent Advances in Diesel Engine Catalytic Soot Abatement: Structured Catalysts and Alternative Approaches

Meloni

Palma

2020

Catalysts

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Diesel engine emissions are typically composed of several hundred chemical compounds, partly present in the gas phase and partly in solid phase as particles, the so-called particulate matter or soot. The morphology of the catalyst is an important characteristic of soot particles’ abatement, since a good contact between catalyst and soot is mandatory. For practical purposes, the active species should be supported as a film on the structured carrier, in order to allow simultaneous soot filtration and combustion. This review focuses on the most recent advances in the development of structured catalysts for diesel engine catalytic soot combustion, characterized by different active species and supports, as well as by different geometric configurations (monoliths, foams, ceramic papers, or wire mesh); the most important peculiar properties are highlighted and summarized. Moreover, a critical review of the most recent advances in modeling studies is also presented in this paper. In addition, some highlights on some of the most recent alternative approaches proposed for limiting the soot emissions from diesel engines have been given, delineating feasible alternatives to the classical strategies nowadays used.

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Section: Other Simulation Approachesmentioning

confidence: 99%

Most Recent Advances in Diesel Engine Catalytic Soot Abatement: Structured Catalysts and Alternative Approaches

Meloni

Palma

2020

Catalysts

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“…A simple P&ID controller is designed for our system operating in transient condition. The controller objective is to maintain the ammonia surface coverage 4 at a low level which minimizes NH 3 slip but is sufficient to maximize NO x conversion.…”

Section: System Controlmentioning

confidence: 99%

“…Modelling of the SCR-in-DPF system is complicated. The main challenge is how to best capture the complexity of the physical and chemical phenomena-e.g., the competition of soot oxidation and SCR reaction for available NO 2 , or the interaction of washcoat loading on deNOx performance, PM filtration efficiency and system pressure drop-in a simplified but adequate representation [4]. Therefore research is ongoing on the development of an SCR-in-DPF model which achieves the right balance between adequacy and complexity, and which can form the basis of a control algorithm that can be implemented within an engine control unit (ECU).…”

mentioning

confidence: 99%

A Low Order Model of SCR-in-DPF Systems with Proper Orthogonal Decomposition

Olowojebutu

Steffen

2018

SAE Technical Paper Series

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his paper presents a method to achieve a low order system model of the urea-based SCR catalyst coated filter (SCR-in-DPF or SCRF or SDPF), while preserving a high degree of fidelity. Proper orthogonal decomposition (POD), also known as principal component analysis (PCA), or Karhunen-Loéve decomposition (KLD), is a statistical method which achieves model order reduction by extracting the dominant characteristic modes of the system and devises a low-dimensional approximation on that basis. The motivation for using the POD approach is that the low-order model directly derives from the high-fidelity model (or experimental data) thereby retains the physics of the system. POD, with Galerkin projection, is applied to the 1D + 1D SCR-in-DPF model using ammonia surface coverage and wall temperature as the dominant system states to achieve model order reduction. The performance of the low-order POD model (with only a few basis modes) shows good agreement with the high fidelity model in steady and transient states analyses. This shows the promise of the application of POD in exhaust aftertreatment system (EATS) modelling to achieve high fidelity low order models. In addition system control design is easier for the reduced order model using a modern approach. We demonstrate the performance of a model-based controller applied to the low-order POD model to minimize ammonia slip for a transient test cycle. 10

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“…Modelling of the SCRcoated filter system is, however, complicated. The main challenge is how to best capture the complexity of the physical and chemical phenomena-e.g., the competition of soot oxidation and SCR reaction for available NO 2 , the interaction of washcoat loading on deNOx performance, PM filtration efficiency and system pressure drop-in a simplified but adequate representation [7]. This work is focused on the development of an SCR-in-DPF model which achieves the right balance between adequacy and complexity and which can form the basis of a control algorithm that can be implemented within an engine control unit (ECU).…”

Section: Introductionmentioning

confidence: 99%

SCR-Filter Model Order Reduction (1): Development and Validation of the Base “High-Fidelity” Model

Olowojebutu

Steffen

Bush³

2019

Emiss. Control Sci. Technol.

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Catalysed diesel particulate filters (c-DPF) have been described as multifunctional reactor systems. Integration of selective catalytic reduction (SCR) functionality in the DPF enhances filter performance to achieve nitrous oxides (NOx) treatment along with particulate matter (PM) collection. The physical and chemical aspects of the integrated SCR-filter make modelling difficult. The goal of this work is to develop a low-complexity model of the SCR-filter system with good fidelity. The first part of our work—presented in this paper—lays out the structure of the SCR-filter model and highlights a new approach to implement faster than real-time solution to the “full-order” or “high-complexity” model. The validated model was applied to evaluate the impact of diffusion on deNOx functionality of the SCR-filter system in a simulated characterisation exercise for the SCR-filter unit. We found that internal (pore) diffusion (effective diffusivity coefficient) and external channel to wall diffusion (mass transfer coefficient) orthogonal to the channel direction are significant for accurate characterisation of the deNOx performance of the SCR-coated filter system. System modelling can be used to select the geometric properties of the monolith (length and density of the SCR-coated filter system) and micro-properties of the washcoat (catalyst loading and zoning) to optimise the influence of diffusion on the system performance. The main contribution of this paper is the presentation of a different approach to implementing the solution to the cDPF model and in enough detail so that it can be easily replicated.

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A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

Cited by 16 publications

References 63 publications

Most Recent Advances in Diesel Engine Catalytic Soot Abatement: Structured Catalysts and Alternative Approaches

Most Recent Advances in Diesel Engine Catalytic Soot Abatement: Structured Catalysts and Alternative Approaches

A Low Order Model of SCR-in-DPF Systems with Proper Orthogonal Decomposition

SCR-Filter Model Order Reduction (1): Development and Validation of the Base “High-Fidelity” Model

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