Filters & Substrates


Vehicular Emissions in Review 
SAE #: 2014-01-1491 | View PDF 
        

SAE Paper 2014-01-1491(c) 2014 SAE International. This paper is posted on this website with permission from SAE International.  It may not be shared, downloaded, duplicated, or transmitted in any manner without prior written permission from SAE.


AUTHOR:
Timothy V. Johnson –  Corning Incorporated

ABSTRACT:
The review paper summarizes major developments in vehicular emissions regulations and technologies in 2013. First, the paper covers the key regulatory developments in the field, including proposed light-duty (LD) criteria pollutant tightening in the US; and in Europe, the continuing developments towards real-world driving emissions (RDE) standards. Significant shifts are occurring in China and India in addressing their severe air quality problems. The paper then gives a brief, high-level overview of key developments in fuels. Projections are that we are in the early stages of oil supply stability, which could stabilize fuel prices. LD 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 or will soon be demonstrating 50% brake thermal efficiency using common approaches. NOx control technologies are then summarized, including SCR (selective catalytic reduction) systems and SCR filter developments. Emphasis is on low-temperature deNOx and integration of components and control. Diesel PM (particulate matter) reduction technologies are evolving around the behavior of ash deposits and SCR integration. Filters for direct injection gasoline applications are developing very rapidly, and in some cases the back pressure, light-off characteristics, and emissions reductions are very similar to standard three way catalysts (TWCs). Oxidation catalysts mainly involve developments towards stubborn problems, like 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 matching engine calibration with emissions system characteristics; and on lean burn gasoline emissions control.


Vehicular Emissions in Review 
SAE #: 2013-01-0538 | View PDF             

SAE Paper 2013-01-0538(c) 2013 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.


AUTHOR:
Timothy V. Johnson-Corning Incorporated

ABSTRACT:
This review paper summarizes major developments in vehicular emissions regulations and technologies (light-duty, heavy-duty, gasoline, diesel) in 2012. First, the paper covers the key regulatory developments in the field, including finalized criteria pollutant tightening in California; and in Europe, the development of real-world driving emissions (RDE) standards. The US finalized LD (light-duty) greenhouse gas (GHG) regulation for 2017-25. The paper then gives a brief, high-level overview of key developments in LD and HD engine technology, covering both gasoline and diesel. Marked improvements in engine efficiency are summarized for gasoline and diesel engines to meet both the emerging NOx and GHG regulations. HD engines are just starting to demonstrate 50% brake thermal efficiency. NOx control technologies are then summarized, including SCR (selective catalytic reduction) with ammonia, and hydrocarbon-based approaches. Emphasis is on low-temperature deNOx, durability, and cost reduction. PM (particulate matter) reduction technologies are evolving around SCR integration and the behavior of soot and ash deposits. Next, DOC (diesel oxidation catalyst) developments are summarized. They mainly involve better understanding of aging and substitution of base metals oxides for precious metal. The paper then discusses some key developments in gasoline emission controls, focusing on new coated GPF (gasoline particulate filter) understanding. Advanced three-way catalysts improve with layered coating technology, and with improved understanding on engine calibration.


Electronic and Atomistic Roles of Cordierite Substrate in Sintering of Washcoated Catalysts for Automotive Exhaust Gas Emissions Control: Multiscale Computational Chemistry Approach based on Ultra-Accelerated Quantum Chemical Molecular Dynamics Method
SAE #: 2012-01-1292 | View PDF        

SAE Paper 2012-01-1292(c) 2012 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHORS:

Akira Miyamoto, Ryo Nagumo, Ai Suzuki, Ryuji Miura, Hideyuki Tsuboi, Nozomu Hatakeyama, Hiromitsu Takaba and Sumio Kozawa-Tohoku Univ.
Athonu Chatterjee and Akira Okada-Corning Incorporated

ABSTRACT:
Multi-scale computational chemistry methods based on the ultra-accelerated quantum chemical molecular dynamics (UA-QCMD) are applied to investigate electronic and atomistic roles of cordierite substrate in sintering of washcoated automotive catalysts. It is demonstrated that the UA-QCMD method is effective in performing quantum chemical molecular dynamics calculations of crystals of cordierite, Al2O3 and CeZrO4 (hereafter denoted as CZ). It is around 10,000,000 times faster than a conventional firstprinciples molecular dynamics method based on densityfunctional theory (DFT). Also, the accuracy of the UAQCMD method is demonstrated to be as high as that of DFT. On the basis of these confirmations and comparison, we performed extensive quantum chemical molecular dynamics calculations of surfaces of cordierite, Al2O3 and CZ, and interfaces of Al2O3 and CZ with cordierite at various temperatures. These calculations coupled with mesoscopic sintering simulations have demonstrated that the cordierite surface forms strong bonds with Al2O3 and CZ, which was seen to improve significantly the sintering property of washcoated catalysts under various conditions.


Vehicular Emissions in Review
SAE #: 2012-01-0368 | View PDF        

SAE Paper 2012-01-0368(c) 2012 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHOR:
Timothy V. Johnson-Corning Incorporated

ABSTRACT:
This review paper summarizes major developments in vehicular emissions regulations and technologies (light-duty, heavy-duty, gasoline, diesel) in 2011. First, the paper covers the key regulatory developments in the field, including proposed criteria pollutant tightening in California; and in Europe, the newly proposed PN (particle number) regulation for direct injection gasoline engines, test cycle development, and in-use testing discussions. The proposed US LD (light-duty) greenhouse gas (GHG) regulation for 2017-25 is reviewed, as well as the finalized, first-ever, US HD (heavy duty) GHG rule for 2014-17. The paper then gives a brief, high-level overview of key emissions developments in LD and HD engine technology, covering both gasoline and diesel. Emissions challenges include lean NOx remediation for diesel and leanburn gasoline to meet both the emerging NOx and GHG regulations. NOx control technologies are then summarized, including SCR (selective catalytic reduction) with ammonia, and hydrocarbon-based approaches. Nitrous oxide (N2O) emissions are also addressed. These technologies are achieving >95% deNOx efficiency averaged over the certification test cycles. PM (particulate matter) reduction technologies are evolving around new DPF (diesel particulate filter) materials for reduced back pressure and SCR integration. Next, DOC (diesel oxidation catalyst) developments are summarized. They mainly involve NO oxidation to NO2 as a function of catalyst formulation and hydrocarbon oxidation parameters. Finally, the paper discusses some key developments gasoline emission controls. Advanced three-way catalysts improve with zone coating technology, and with precious metal thrifting. Sulfur impacts are significant on the new formulations. Finally, the emerging technology of GPFs (gasoline particulate filters) is summarized.


Measurement and Prediction of Filtration Efficiency Evolution of Soot Loaded Diesel Particulate Filters
SAE #: 2012-01-0363 | View PDF      

SAE Paper 2012-01-0363(c) 2012 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHORS:

Danhong Zhong, Suhao He, Pushkar Tandon, Maxime Moreno and Thorsten Boger-Corning Incorporated

ABSTRACT:
Experimental and theoretical methods are presented to characterize the transient filtration efficiency (FE) behavior of Diesel Particulate Filters (DPFs) exposed to soot laden exhaust gas streams under laboratory and engine exhaust conditions. A (1+1) dimensional transient model, comprising a one dimensional channel model in combination with a one dimensional wall microstructure model is presented to study the sensitivity of the FE behavior on DPF microstructure and geometry properties, along with the impact of the hydrodynamic and aerosol flow conditions (flow rate, temperature, aerosol characteristics). The dynamic model also considers the dynamic soot oxidation by passive regeneration. The model has been validated through use of an extensive set of experimental data obtained under different operating conditions and with DPFs of different microstructure. Evolution of dynamic FE under dynamic engine operating conditions, including the typical emission cycles (FTP, WHTC, etc.) is predicted and the results are compared with the experimental measurements of mass based filtration efficiency. In general, the predictions from the model have been found to be in good agreement with the experiments.


Diesel Emission Control in Review
SAE #: 2011-01-0304 | View PDF        

SAE Paper 2011-01-0304(c) 2011 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHOR:
Timothy V. Johnson -Corning Incorporated

ABSTRACT:
This review summarizes the latest developments in diesel emissions regarding regulations, engines, NOx (nitrogen oxides) control, particulate matter (PM) reductions, and hydrocarbon (HC) and CO oxidation.

Regulations are advancing with proposals for 70% tightening of fleet average light-duty (LD) criteria emissions likely to be proposed in California for ∼2016-22. CO 2 regulations in both the heavy - and light-duty sectors will also tighten and impact diesel engines and emissions, probably long into the future.

Engine technology is addressing these needs. Light-duty diesel engines are making incremental gains with combustion enhancements that allow downsizing for CO 2 savings. Heavy-duty (HD) engine show trade-offs between hardware recipes, exhaust deNOx control, and fuel consumption.

Much has recently been reported on optimized selective catalytic reduction (SCR) systems, with many reports on improving low temperature performance with proper reductant management and new catalyst formulations. Developments on HC-based deNOx are focused on lean NOx traps (LNTs) and the LNT+SCR systems, wherein the LNT is calibrated to generate ammonia for use in a downstream SCR.

PM control with DPFs (diesel particulate filters) are very effective. DPF regeneration advances are reported in strategy, catalyst utilization, and substrate design. Biodiesel effects on DPF functions are becoming clearer.

Finally, diesel oxidation catalysts (DOCs) are investigated in the context of impacting NO 2 coming from a downstream catalyzed DPF for use in an SCR system. Hydrocarbon removal from the DOC is quite important in this regard.


A Next Generation Cordierite Diesel Particle Filter with Significantly Reduced Pressure Drop
SAE #: 2011-01-0813 | View PDF        

SAE Paper 2011-01-0813(c) 2011 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHORS:
Thorsten Boger, Suhao He, Thomas Collins, Achim Heibel, Douglas Beall and Christophe Remy -Corning Incorporated

ABSTRACT:
Diesel particle filters (DPF) have become a standard after treatment component for all current and future on-road diesel engines used in the US. In Europe the introduction of EUVI is expected to also result in the broad implementation of DPF's. The anticipated general trend in engine technology towards higher engine out NOx/PM ratios results in a somewhat changing set of boundary conditions for the DPF predominantly enabling passive regeneration of the DPF. This enables the design of a novel filter concept optimized for low pressure drop, low thermal mass for optimized regeneration and fast heat-up of a downstream SCR system, therefore reducing CO2 implications for the DPF operation. In this paper we will discuss results from a next generation cordierite DPF designed to address these future needs. The new materials are based on a thinwall design with optimized material and microstructure, resulting in an almost linear pressure drop response with soot loading in the bare and catalyzed state. A significant reduction in soot loaded pressure drop for uncoated and coated filters is demonstrated of the new filter design vs. current EPA 2010 filter technologies. The optimized microstructure also enables high filtration efficiency for mass and number. Results from a wide range of regeneration experiments will be used to discuss the thermal operating window of the new material and the thermal response during normal operation and active regeneration. A uniform temperature distribution and the fast thermal response of the low mass filter minimize implications on fuel consumption.


Next Generation Aluminum Titanate Filter for Light Duty Diesel Applications
SAE #: 2011-01-0816 | View PDF        

SAE Paper 2011-01-0816(c) 2010 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHOR:
Thorsten Boger, Joshua Jamison, Jason Warkins, Nancy Golomb, Christopher Warren and Achim Heibel -Corning Incorporated

ABSTRACT:
With the introduction of the current EU5 standards the diesel particulate filter has become a key element in the aftertreatment of diesel passenger cars. The upcoming future emission standards target primarily a further reduction in NOx emission as well as reduced fleet average CO 2 emissions. Although the particulate filter has no direct influence on the reduction of these species, the needs of future aftertreatment systems impose additional requirements on advanced filter technologies. In this paper we are introducing two new filter products based on a new low porosity aluminum titanate family that complement the current DuraTrap ® AT filter products. The new products offer the potential for an increased soot mass limit or a significant reduction in pressure drop. The enhanced performance of the new filter products is discussed and demonstrated in a large number of experimental data obtained in engine bench tests. Pressure drop, filtration, survivability, and durability data are presented.


Diesel Emission Control in Review
SAE #: 2010-01-0301 | View PDF       
SAE Paper 2010-01-0301(c) 2010 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.


AUTHOR:
Timothy V. Johnson -Corning Incorporated

ABSTRACT:
This review summarizes the latest developments in diesel emissions regarding regulations, engines, NOx (nitrogen oxides) control, particulate matter (PM) reductions, and hydrocarbon (HC) and CO oxidation.

Regulations are advancing with proposals for PN (particle number) regulations that require diesel particulate filters (DPFs) for Euro VI in 2013-14, and SULEV (super ultra low emission vehicle) fleet average light-duty (LD) emissions likely to be proposed in California for ∼2017. CO2 regulations will also impact diesel engines and emissions, probably long into the future.

Engine technology is addressing these needs. Heavy-duty (HD) research engines show 90% lower NOx at the same PM or fuel consumption levels as a reference 2007 production engine. Work is starting on HD gasoline engines with promising results. In light duty (LD), engine downsizing is progressing and deNOx is emerging as a fuel savings strategy.

Much has recently been reported on optimized selective catalytic reduction (SCR) systems. The SCR catalyst can be placed before, after, or on the DPF. Work is progressing on non-urea ammonia systems, mixed zeolite catalysts, and on fundamental understanding on issues like ammonia storage, sulfur impacts, and reaction mechanisms. Developments on HC-based deNOx, like lean NOx traps (LNTs), result in a better understanding of durability, reduction in desulfation temperatures, and the use of LNT+SCR systems, wherein the LNT is calibrated to generate ammonia for use in a downstream SCR.

PM control is very effective. US2007 HD engines are very clean, with the DPF systems delivering PM, HC, and CO emissions at levels lower than 10% of the regulation. DPF regeneration advances are reported in strategy, modeling PM loading, and catalyst utilization. The effect of catalyst coatings on PN emissions, and behavior of captured ash is becoming better understood. NO 2 based regeneration of soot is very critical for proper functioning of partial filters.

Biodiesel effects on DPF functions are becoming clearer. Finally, diesel oxidation catalysts (DOCs) are being developed for use with premixed combustion engine strategies that function better at low temperatures, low oxygen levels, and at high HC+CO levels. The problem of platinum (Pt) migration to SCR catalysts from DOCs exposed to high temperatures for long times (850°C, 16 hours) is alleviated somewhat by using palladium (Pd) to replace some of the platinum.


Diesel Emission Control in Review
SAE #: 2010-01-1276 | View PDF       

SAE Paper 2010-01-1276(c) 2010 SAE International.  This paper is posted on this website with permission from SAE International.  As a user of this website, you are permitted to view this paper on-line, and print one copy of this paper at no cost for your use only.  This paper may not be copied, distributed or forwarded without permission from SAE.

AUTHOR:
Timothy V. Johnson -Corning Incorporated

ABSTRACT:
The topic of CO2 and fuel consumption reductions from vehicles is a very broad and complex issue, encompassing vehicle regulations, biofuel mandates, and a vast assortment of engine and vehicle technologies. This paper attempts to provide a high-level review of all these issues.

Reducing fuel consumption appears not to be driven by the amount of hydrocarbon reserves, but by energy security and climate change issues. Regarding the latter, a plan was proposed by the United Nations for upwards of 80% CO2 reductions from 1990 levels by 2050. Regulators are beginning to respond by requiring ∼25% reductions in CO2 emissions from light-duty vehicles by 2016 in major world markets, with more to come. The heavy-duty sector is poised to follow. Similarly, fuel policy is aimed at energy diversity (security) and climate change impacts. Emerging biofuel mandates require nominally 5-10% CO2 life cycle emissions reductions by 2020. Processes that utilize plant cellulose and waste products show the best intermediate term potential for meeting these goals, but long term trends are towards biofeedstocks for refineries.

Vehicle technologies are emerging to meet the regulatory mandates. Light-duty engine efficiency gains will result in about 30% fuel and CO2 reductions by 2015. Many of the reductions will come from the use of direct injection technology in gasoline engines, and downsizing diesel and gasoline engines for more specific power. CO2 savings shows a general linear relationship with cost. Diesel hybrids offer the greatest CO2 reduction potential. Plug in hybrids can lead to heavy electrification of the fleet for energy diversity and greenhouse gas reductions, but their CO2 reductions are moderate and expensive. Battery performance is generally acceptable, but cost will be a recurring issue. Most light-duty efficiency technologies return money to the consumer over the life of the vehicle, so the CO2 reductions also come with an economic gain to the owner.

In the heavy-duty sector vehicle and operational improvements offer the best gains at 16 to 28% fuel reductions. Engine technology trends are indicating nominally 15% reductions using advancements in currently utilized technologies. Research is shifting to gasoline engines, wherein upwards of 20-25% CO2 reductions might be realized. Heavy duty hybridization is emerging for vocational and urban vehicles, and can offer a 2 to 4 year payback period.

Black carbon reductions from vehicles can have a profound effect on GHG impact, accounting for upwards of ∼20% of CO2 reductions proposed by the Intergovernmental Panel on Climate Change (IPCC) by 2050.


Diesel Emission Control in Review
SAE #: 2009-01-0121 | View PDF      

SAE Paper 2009-01-0121(c) 2009 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHOR:
Timothy V. Johnson -Corning Incorporated

ABSTRACT:
This summary covers representative developments from 2008 in diesel regulations, engine technology, and NOx, particulate matter (PM), and hydrocarbon (HC) control.

Europe is finalizing the Euro VI heavy-duty (HD) regulations for 2013 with the intent of technologically harmonizing with the US. A new particle number
standard will be adopted. California is considering tightening the light-duty fleet average to US Tier 2 Bin 2 levels, and CO2 mandates are emerging in Europe for LD, and in the US for all vehicles.

LD engine technology is focused on downsizing to deliver lower CO2 emissions, enabled by advances in boost and EGR (exhaust gas recirculation). Emerging concepts are shown for attaining Bin 2 emission levels. HD engines will make deNOx systems optional for even the tightest NOx standards, but deNOx systems enable much lower fuel consumption levels and will likely be used.

NOx control is centered on SCR (selective catalytic reduction) for diverse applications. Focus is on cold operation, system optimization, and catalyst durability. LNT (lean NOx trap) performance is advancing and precious metal cost content is decreasing. Desulfation is enhanced, and new compositions are emerging based on alumina and ceria. LNCs (lean NOx catalysts or HCSCR) developments are updated.

Diesel particulate filter (DPF) technology is in a state of optimization and cost reduction. New DPF regeneration strategies are described as well as the new learnings on the fundamentals of soot/catalyst interaction and the impact of DPF pore structure.

Finally an update on diesel oxidation catalysts (DOCs) is provided showing potential solutions for advanced combustion strategies.


Different Approaches to Soot Estimation as Key Requirement for DPF Applications
SAE #: 2009-01-1262 | View PDF      
SAE Paper 2009-01-1262(c) 2009 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Dominik Rose -Corning GmbH
Thorsten Boger - Corning Incorporated

ABSTRACT:
The accuracy of soot estimation is - besides thermal management – one of the key requirements for successful DPF applications. With the implementation of more stringent emissions regulations and requirements for fuel efficiency the importance of high quality soot mass estimation becomes even more relevant. The durability targets for T2B5 and Euro 6 require accurate soot load detection under all driving profiles and customer specific environments – from low speed delivery cycles to high speed extra urban driving profiles. The most fuel and CO2 efficient regeneration strategy relies on knowledge of the current soot mass in the DPF. This paper  escribes several options of soot mass estimation: From an empirical engine out emissions model, combined with a physical soot oxidation model to a physical model in which the pressure drop signal combined with other parameters is used to determine the filter load. Matlab/Simulink models were developed and evaluated for this study using test bench and real world vehicle driving data. This paper describes simple models used as well as the benefits and trade offs for each of the methods. It also provides data on the achieved accuracy in soot mass estimation for commercial diesel particulate filters used in light duty diesel applications.


Oxide Based Particulate Filters for Light-Duty Diesel Applications – Impact of the Filter Length on the Regeneration and Pressure Drop Behavior 
SAE #: 2008-01-0485 | View PDF     

SAE Paper 2008-01-0485(c) 2008 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Thorsten Boger and Ingo-C. Tilgner - Corning GmbH
Min Shen and Yi Jiang -  Corning Incorporated

ABSTRACT:
Diesel particulate filters are becoming a standard for most light duty diesel applications designed for European EU5 and EU6 regulations. Oxide based filter materials are continuing to gain significant interest and have been in high volume serial application since 2005. Compared to carbide materials they show some unique properties.

With respect to the design, the length of a filter is a key variable. Usually the prime design consideration is the desired filter volume. The diameter or frontal area is then usually defined by packaging constraints. Finally, the length is adapted. The paper provides experimental data on the impact this key design parameter has on the pressure drop and the thermal behavior under “worst case” regeneration conditions. A wide range of soot loads (from 4 g/dm³ to 9 g/dm³) as well as filter lengths from 6” to 12” is considered and evaluated under comparable experimental conditions.

The discussion is based on experimental data as well as numerical simulations with a 2D simulator. The simulator is shown to be in good agreement with the experimental observations. In general shorter filters are found to be of advantage. They provide for lower pressure drop and yield lower temperatures and gradients during worst case regeneration conditions. Data are provided that can help to estimate the impact of the filter length on the soot mass limit.


Regeneration Strategies for an Enhanced Thermal Management of Oxide Diesel Particulate Filters
SAE #: 2008-01-0328 | View PDF      

SAE Paper 2008-01-0328(c) 2008 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others. 

AUTHORS:
Thorsten Boger, Dominik Rose and Ingo-C. Tilgner - Corning GmbH
Achim K. Heibel -Corning Incorporated

ABSTRACT:
Diesel particulate filters are expected to be used on most passenger car applications designed to meet coming European emission standards, EU5 and EU6. Similar expectations hold for systems designed to meet US Tier 2 Bin 5 standards. Among the various products oxide filter materials, such as cordierite and aluminum titanate, are gaining growing interest due to their unique properties. Besides the intrinsic robustness of the filter products a well designed operating strategy is required for the successful use of filters. The operating strategy is comprised of two elements: the soot estimation and the regeneration strategy. In this paper the second element is discussed in detail by means of theoretical considerations as well as dedicated engine bench experiments. The impact the key operating variables, soot load, exhaust mass flow, oxygen content and temperature, have on the conditions inside the filter are discussed. Their practical relevance and the ability to use them for control purposes is analyzed. Guidelines are presented that should be considered when applying oxide diesel particulate filters. The differences between oxides and materials with higher thermal conductivity are discussed with respect to the relationship between regeneration conditions and the achievable regeneration efficiency. Experimental data show benefits for oxide materials vs. SiC, expected to come from their low conductivity.For the regeneration strategy a simple approach is proposed and illustrated by means of examples. The benefits of a staged regeneration approach are discussed, using two temperature levels during the regeneration.


Diesel Emission Control in Review 
SAE #: 2008-01-0069 | View PDF     
SAE Paper 2008-01-0069(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHOR:
Timothy V. Johnson - Corning Incorporated

ABSTRACT:
This summary covers the developments from 2007 in diesel regulations, engine technology, and NOx and PM control.

Regulatory developments are now focused on Europe, where heavy-duty regulations have been proposed for 2013. The regulations are similar in technology needs to US2010. Also, the European Commission proposed the first CO2 emission limits of 130 g/km, which are nearly at parity to the Japanese fuel economy standards.

Engines are making very impressive progress, with clean combustion strategies in active development mainly for US light-duty application. Heavy-duty research engines are more focused on traditional approaches, and will provide numerous engine/aftertreatment options for hitting the tight US 2010 regulations. 

NOx control is centered on SCR (selective catalytic reduction) for diverse applications. Focus is on cold operation and system optimization. LNT (lean NOx traps) durability is quantified, and performance enhanced with a sulfur trap. LNCs developments are updated.

Diesel particulate filter (DPF) technology is in a state of optimization and cost reduction. New DPF regeneration strategies are described as well as the new learnings on the fundamentals of soot/catalyst interaction and the impact of DPF pore structure.

Finally an update on diesel oxidation catalysts (DOCs) is provided showing potential issues with advanced combustion strategies, important interactions on NO2 formation, and new formulations for enhanced durability.


Performance Aspects of New Catalyzed Diesel Soot Filters Based on Advanced Oxide Filter Materials 
SAE #: 2007-01-1268 | View PDF 

SAE Paper 2007-01-1268(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
W. A. Cutler and T. Boger - Corning GmbH
A. F. Chiffey, P. R. Phillips, D. Swallow and M. V. Twigg - Johnson Matthey PLC

ABSTRACT:
Catalyzed soot filters are being fitted to an increasing range of diesel-powered passenger cars in Europe. While the initial applications used silicon carbide wallflow filters, oxide-based filters are now being successfully applied. Oxide-based filters can offer performance and system cost advantages for applications involving both a catalyzed filter with a separate oxidation catalyst, and a catalyzed filter-only that incorporates all necessary catalytic oxidation functions. Advanced diesel catalyst technologies have been developed for alternative advanced oxide filter materials, including aluminum titanate and advanced cordierite. In the development of the advanced catalyzed filters, improvements were made to the filter material microstructures that were coupled with new catalyst formulations and novel coating processes that had synergistic effects to give enhanced overall performance. This paper discusses relevant system performance criteria including pressure-drop, emissions, thermalmechanical influences and the overall system durability in tests under certain controlled test conditions.


Improved Lifetime Pressure Drop Management for Robust Cordierite (RC) Filters with Asymmetric Cell Technology (ACT)
SAE #: 2007-01-0920 | View PDF 

SAE Paper 2007-01-0920(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Krishna Aravelli and Achim Heibel - Corning Incorporated, Diesel Technologies Development

ABSTRACT:
The stricter emissions legislation in the US, require the implementation of Diesel Particulate Filters (DPF) for Heavy Duty Diesel engines to meet the 2007 PM emissions targets. Cordierite based wall-flow filters with high filtration efficiency, low op and good thermal durability are the product of choice for these applications. Continuous passive oxidation of the soot by NO2 is desired, however under certain operating and ambient conditions periodic active oxidation of the soot at elevated temperatures (>550ºC) is required. A part of the PM emissions of the engine contains noncombustible contributions (ashes). These materials accumulate in the filter over lifetime, resulting in an increase in pressure drop as well as a reduction of the filter volume available for soot accumulation. As the pressure drop rises above manageable levels from a performance perspective, ash cleaning of the filter is required. The ash storage capacity of the filter determines the service interval for the filter. Long service intervals are desired by the end customer. To mitigate the impact of the ash accumulation in the filter, Corning Incorporated has developed filters with the proprietary asymmetric cell technology (ACT), providing high ash capacity with good strength attributes. These filters have larger inlet and smaller outlet channels and therefore a higher volume available for ash storage.

The present work summarizes the results of on-engine (HD) ash testing on uncoated Robust Cordierite (RC) filters – Ø267mmX305mm (Ø10.5”x12”) in both Standard (200/19) and ACT (270/16) design configurations. The work demonstrates, for an equal size filter a 30% improved ash storage capacity and therefore longer service interval for the ACT design over the standard filter. Good durability of the filters for a long operation timeframe (up to 2700h) was demonstrated. Furthermore the paper summarizes a wide set of post testing evaluations, both non-destructive and destructive to understand the ash distribution and interactions in the filter.


Performance Evaluations of Aluminum Titanate Diesel Particulate Filters
SAE #: 2007-01-0656 | View PDF 

SAE Paper 2007-01-0656(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
R. S. Ingram-Ogunwumi, Q. Dong, T. A. Murrin, R. Y. Bhargava, J. L. Warkins and A. K. Heibel - Corning Incorporated

ABSTRACT:
Over the past decade, regulations for mobile source emissions have become more stringent thus, requiring advances in emissions systems to comply with the new standards. For the popular diesel powered passenger cars particularly in Europe, diesel particulate filters (DPFs) have been integrated to control particulate matter (PM) emissions. Corning Incorporated has developed a new proprietary aluminum titanate-based material for filter use in passenger car diesel applications. Aluminum titanate (hereafter referred to as AT) filters were launched commercially in the fall of 2005 and have been equipped on more than several hundred thousand European passenger vehicles. Due to their outstanding durability, filtration efficiency and pressure drop attributes, AT filters are an excellent fit for demanding applications in passenger cars.

Extensive testing was conducted on engine to evaluate the survivability and long-term thermo-mechanical durability of AT filters. Catalyzed filters were first tested to failure under severe uncontrolled regenerations to define filter survivability limits by means of filter maximum temperatures and thermal gradients. In the second phase filter durability was evaluated, exposing the AT filter to hundreds of high temperature regenerations. This paper demonstrates a broad window of operation for AT filters under extreme exposures. Furthermore the pressure drop as well as the filtration performance of the filters was investigated and compared to commercially available filter alternatives.


Advanced Mounting System for Light Duty Diesel Filter
SAE #: 2007-01-0471 | View PDF

SAE Paper 2007-01-0471(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
S. T. Nickerson, C. B. Sawyer and S. T. Gulati - Corning Incorporated
S. D. Fernandes, Jr. and J. R. Olson - Unifrax Corporation

ABSTRACT:
This paper employs a systematic approach to packaging design and testing of a system and its components in order to determine the long term durability of light duty diesel filters. This effort has utilized a relatively new aluminum titanate filter technology as well as an advanced support mat technology engineered to provide superior holding force at lower temperatures while maintaining its high temperature performance. Together, these two new technologies form a system that addresses the unique operating conditions of diesel engines. Key physical properties of both the filter and the mat are demonstrated through laboratory testing. The system behavior is characterized by various laboratory techniques and validation procedures.


Diesel Emission Control in Review
SAE #: 2007-01-0233 | View PDF 

SAE Paper 2007-01-0233(c) 2007 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Timothy V. Johnson - Corning Incorporated

ABSTRACT:
This summary covers the developments from 2006 in diesel regulations, engine combustion, and NOx and PM remediation.

Regulatory developments are now focused on Europe, where light-duty Euro 5 and 6 regulations have been proposed for 2009 and 2014, respectively. The regulations are lass stringent than those in the US, but options exist for adopting European vehicles for the US market. Europe is just beginning to look at heavy-duty regulations for 2012 and beyond.

Engines are making very impressive progress, with clean combustion strategies in active development mainly for US light-duty application. Heavy-duty research engines are more focused on traditional approaches, and will provide numerous engine/aftertreatment options for hitting the tight US 2010 regulations.
 
NOx control is focusing on SCR (selective catalytic reduction) for diverse applications. Focus is on cold operation, durability, secondary emissions, and system optimization. Aged LNTs (lean NOx traps) are effective up to about 60-70% deNOx efficiency, and are being considered for light-duty and some light heavy-duty applications. There is growing interest in supplementing LNT performance with integrated SCR, which utilizes ammonia generated in the LNT during rich regenerations.

Diesel particulate filter technology is in a state of optimization and cost reduction. Very sophisticated management strategies are being utilized, which open up options for new filter materials and alternative system architectures. Secondary emissions issues are emerging and are being addressed.


Relative Benefits of Various Cell Density Ceramic Substrates in Different Regions of the FTP Cycle
SAE #: 2006-01-1065 | View PDF

SAE Paper 2006-01-1065(c) 2006 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Katherine W. Hughes - Corning Incorporated
David Gian and Jason Calleja - FEV Engine Technology, Inc.

ABSTRACT:
Continuous improvement in vehicle emissions is necessary to meet ever tightening regulations. These regulations are advancing in both passenger and light truck vehicle markets, currently at different rates. Divergent design requirements and target markets for these platforms create unique conditions for aftertreatment needs.

To understand the performance of various products in these categories and the potential for optimization, we examine various ultrathin-wall products in the context of a close-coupled configuration in a SULEV vehicle. In addition, these comparisons are carried over to a larger platform to show the performance trends in the context of the sport utility vehicle category.

This study considers converter performance in FTP tests, examining bag data, light-off behavior, pressure drop comparisons and front and rear converter contributions. Conclusions are drawn regarding the optimization of converter substrate selection for various target design criteria.


Diesel Emission Control in Review
SAE #: 2006-01-0030 | View PDF 

SAE Paper 2006-01-0030(c) 2006 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
Timothy V. Johnson - Corning Incorporated

ABSTRACT:
The paper summarizes the key developments in diesel emission control, generally for 2005. Regulatory targets for the next 10 years and projected advancements in engine technology are used to estimate future emission control needs. Recent NOx control developments on selective catalytic reduction (SCR), lean NOx traps (LNT) and lean NOx catalysts (LNC) are then summarized. Likewise, the paper covers important recent developments on diesel particulate filters (DPFs), summarizing regeneration strategies, new filter and catalyst materials, ash management, and PM measurement. Recent developments in diesel oxidation catalysts are also briefly summarized. Finally, the paper discusses examples of how it is all pulled together to meet the tightest future regulations.


Aluminum Titanate Compositions for Diesel Particulate Filters 
SAE #: 2005-01-0583 | View PDF 

SAE Paper 2005-01-0583(c) 2005 SAE International.  This paper is posted on this website with permission from SAE International. This SAE paper is for viewing only, and may not be printed, copied, distributed or forwarded to others, or used by others.

AUTHORS:
S. B. Ogunwumi, P. D. Tepesch, T. Chapman, C. J. Warren, I. M. Melscoet-Chauvel and D. L. Tennent - Corning Incorporated

ABSTRACT:
Compositions in the mixed strontium/calcium feldspar ([Sr/Ca]O.Al2O3.2SiO2) - aluminum titanate (Al2O3.TiO2) system were investigated as alternative materials for diesel particulate filter application. A key attribute of these compositions is their low coefficient of thermal expansion. Samples were prepared with porosities of >50% and with average pore sizes of between 12 and 16um. Coupled with monolithic fabrication, the superior thermal shock resistance, increased resistance to ash attack, and high volumetric heat capacity of these materials provide advantages over other products available today. Testing to date demonstrates that (bare and catalyzed) aluminum titanate-based filters provide excellent chemical durability and pressure drop performance.