Theoretical and Experimental Analysis of Ash Accumulation and Mobility in Ceramic Exhaust Particulate Filters and Potential for Improved Ash Management

Sappok, Alexander; Wang, Yujun; Wang, Ruo‐Qian; Kamp, Carl Justin; Wong, Victor W.

doi:10.4271/2014-01-1517

Cited by 62 publications

(42 citation statements)

References 25 publications

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“…This opening of pores in the soot cake provides an explanation for why the measured pressure drop approaches that of a clean PF after roughly 50 % regeneration. Other studies in the recent past have employed optical techniques to observe the regeneration process [3][4][5]. Although less quantitative than the approach employed here, similar observations were noted.…”

Section: Particulate Layer Thickness and Density During Regeneration supporting

confidence: 77%

“…Gas flow would be expected to swirl in the rear of the DPF and interact more frequently with the walls; thus, the earlier regeneration occurs here first. This flow effect is also discussed in the work by Sappok et al where the radial velocity is predicted to increase at the rear compared to the front and middle [4]. Complete regeneration occurring first at the outlet in our study does differ from their conceptual model; however, the focus of their study was on the nature of ash deposits and flow and with a high amount of ash blocking access to the soot in the rear.…”

Section: Particulate Layer Thickness and Density During Regeneration supporting

confidence: 59%

“…As has been reported elsewhere [2][3][4][5] and will be shown again in this study, this approach can be significantly misleading when estimating the amount of soot remaining in the filter, and thus, a better understanding of soot distribution during the regeneration process is needed.…”

Section: Introductionmentioning

confidence: 60%

See 2 more Smart Citations

Progression of Soot Cake Layer Properties During the Systematic Regeneration of Diesel Particulate Filters Measured with Neutron Tomography

Toops

Pihl

Finney

et al. 2015

Emiss. Control Sci. Technol.

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Although particulate filters (PFs) have been a key component of the emission control system for modern diesel engines, there remain significant questions about the basic regeneration behavior of the filters and how it changes with accumulation of increasing soot layers. This effort describes a systematic deposition and regeneration of particulate matter in 25-mm diameter×76-mm long wall-flow PFs composed of silicon carbide (SiC) material. The initial soot distributions were analyzed for soot cake thickness using a nondestructive neutron imaging technique. With the PFs intact, it was then possible to sequentially regenerate the samples and reanalyze them, which was performed after nominal 20, 50, and 70 % regenerations. The loaded samples show a relatively uniform distribution of particulate with an increasing soot cake thickness and nearly identical initial density of 70 mg/cm 3 . During regeneration, the soot cake thickness initially decreases significantly while the density increases to 80-90 mg/cm 3 . After ∼50 % regeneration, the soot cake thickness stays relatively constant, but instead, the density decreases as pores open up in the layer (∼35 mg/cm 3 at 70 % regeneration). Complete regeneration initially occurs at the rear of the PF channels. With this information, a conceptual model of the regeneration is proposed.

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Section: Particulate Layer Thickness and Density During Regeneration supporting

confidence: 77%

Section: Particulate Layer Thickness and Density During Regeneration supporting

confidence: 59%

See 1 more Smart Citation

Progression of Soot Cake Layer Properties During the Systematic Regeneration of Diesel Particulate Filters Measured with Neutron Tomography

Toops

Pihl

Finney

et al. 2015

Emiss. Control Sci. Technol.

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show abstract

“…Sappok, et al (74) reported on their latest work in this regard. The amount of soot accumulated in the filter prior to regeneration plays a key role in influencing the extent of ash migration from the channel walls to the back of the filter.…”

Section: Diesel Particulate Filters (Dpf)mentioning

confidence: 96%

Review of Vehicular Emissions Trends

Johnson

2015

SAE Int. J. Engines

207

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This review paper summarizes major developments in vehicular emissions regulations and technologies from 2014. The paper starts with the key regulatory advancements in the field, including newly proposed Non-Road Mobile Machinery regulations for 2019-20 in Europe, and the continuing developments towards real driving emissions (RDE) standards. An expert panel in India proposed a roadmap through 2025 for clean fuels and tailpipe regulations. LD (light duty) and HD (heavy-duty) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging NOx and GHG regulations. HD engines are demonstrating more than 50% brake thermal efficiency using methods that can reasonably be commercialized. Next, NOx control technologies are summarized, including SCR (selective catalytic reduction), lean NOx traps, and combination systems. Emphasis is on durability and control. Diesel PM (particulate matter) reduction findings are evolving around the behavior of the soot cake and PM sensors. Gasoline particulates are further described and gasoline particulate filter regeneration is now better understood. Oxidation catalysts mainly involve developments towards stubborn problems, like sulfur tolerance, low-temperature performance with exhaust with high hydrocarbon and CO, and methane oxidation. Finally, the paper discusses some key developments in gasoline gaseous emission control, focusing on meeting new regulatory requirements in the US, durability, and on lean burn gasoline emissions control.

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“…For instance, EPA has required a 150,000 mile minimum filter maintenance interval for 2007 model year heavy duty v'ehicles [12]. Other adverse effects of ash include inducing the DPF corrosion at high temperature [13] and increasing the frequency of active regeneration events [14]. Hence, a thorough understanding of ash properties and their impact on DPF performance is critical to ensure the design compliance to regulatory requirements at the end of useful life.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Study of Ash Impact on DPF Backpressure and Regeneration Behaviors

Liu¹,

Su²,

Clerc³

et al. 2015

SAE Int. J. Engines

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One field-returned DPF loaded with a high amount of ash is examined using experimental and modeling approaches. The ash-related design factors are collected by coupling the inspection results from terahertz spectroscopy with a calibrated DPF model. The obtained ash packing density, ash layer permeability and ash distribution profile are then used in the simulation to assess the ash impact on DPF backpressure and regeneration behaviors. The following features have been observed during the simulation:1. The ash packing density, ash layer permeability and ash distribution profile should be collected at the same time to ensure the accurate prediction of ash impact on DPF backpressure. Missing one ash property could mislead the measurement of the other two parameters and thus affects the DPF backpressure estimation.2. The ash buildup would gradually increase the frequency for the backpressure-based active soot regeneration. However, the accumulated ash reduces the energy density during the regeneration event as well as adsorbing exotherm, lowering the thermal cracking risk.

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Theoretical and Experimental Analysis of Ash Accumulation and Mobility in Ceramic Exhaust Particulate Filters and Potential for Improved Ash Management

Cited by 62 publications

References 25 publications

Progression of Soot Cake Layer Properties During the Systematic Regeneration of Diesel Particulate Filters Measured with Neutron Tomography

Progression of Soot Cake Layer Properties During the Systematic Regeneration of Diesel Particulate Filters Measured with Neutron Tomography

Review of Vehicular Emissions Trends

Experimental and Modeling Study of Ash Impact on DPF Backpressure and Regeneration Behaviors

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