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Szailer, Tamas
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In-Use Compliance Opportunity for Diesel Powertrains

FEV Europe GmbH-Marcel Romijn
FEV GmbH-Korfer Thomas
Published 2018-04-03 by SAE International in United States
In-use compliance under LEV III emission standards, GHG, and fuel economy targets beyond 2025 poses a great opportunity for all ICE-based propulsion systems, especially for light-duty diesel powertrain and aftertreatment enhancement. Though diesel powertrains feature excellent fuel-efficiency, robust and complete emissions controls covering any possible operational profiles and duty cycles has always been a challenge. Significant dependency on aftertreatment calibration and configuration has become a norm. With the onset of hybridization and downsizing, small steps of improvement in system stability have shown a promising avenue for enhancing fuel economy while continuously improving emissions robustness. In this paper, a study of current key technologies and associated emissions robustness will be discussed followed by engine and aftertreatment performance target derivations for LEV III compliant powertrains. The core of the discussion will be focused on identifying opportunities in engine and aftertreatment hardware and controls to position the diesel applications appropriately for future in-use compliance. Additionally, the authors will discuss the potential diesel powertrain hardware enhancements that could deliver improved emissions robustness while saving fuel, in real-world operation. Since…
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OBD Diagnostic Strategies for LEVIII Exhaust Gas Aftertreatment Concepts

SAE International Journal of Passenger Cars - Mechanical Systems

FEV GmbH-Matthias Kotter
FEV Group Holding GmbH-Thomas Koerfer
  • Journal Article
  • 2015-01-1040
Published 2015-04-14 by SAE International in United States
Upcoming motor vehicle emission regulations, such as California's LEVIII, continue to tighten emission limitations in diesel vehicles. These increasingly challenging emission requirements will be met by improving the combustion process (reducing engine-out emissions), as well as improving the exhaust gas aftertreatment efficiency.Furthermore, intricate On-Board Diagnostics (OBD) systems are required to properly diagnose and meet OBD regulation requirements for complex aftertreatment systems. Under these conditions, current monitoring strategies are unable to guarantee reliable detection of partially failed systems. Additionally, new OBD regulations require aftertreatment systems to be diagnosed as a whole.This paper covers potential OBD strategies for LEVIII aftertreatment concepts with regard to regulation compliance and robustness, while striving to use existing sensor concepts.
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Impact of Sulfur-Oxides on the Ammonia Slip Catalyst Performance

Cummins Inc.-Michael Andrew Smith, Krishna Kamasamudram, Tamas Szailer, Ashok Kumar, Aleksey Yezerets
Published 2014-04-01 by SAE International in United States
The ammonia slip catalyst (ASC), typically composed of Pt oxidation catalyst overlaid with SCR catalyst, is employed for the mitigation of NH3 slip originating from SCR catalysts. Oxidation and SCR functionalities in an ASC can degrade through two key mechanisms i) irreversible degradation due to thermal aging and ii) reversible degradation caused by sulfur-oxides. The impact of thermal aging is well understood and it mainly degrades the SCR function of the ASC and increases the NH3 conversion to undesired products [1]. This paper describes the impact of sulfur-oxides on critical functions of ASC and on NH3 oxidation activity and selectivity towards N2, NOx and N2O. Furthermore impact of desulfation under selected conditions and its extent of ASC performance recovery is explained.
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Comparison of SCR Catalyst Performance on RMC SET Emission Cycle between an Engine and a High Flow Burner Rig

Cummins Inc.-Pranay Nagar, Tamas Szailer
Southwest Research Institute-Cynthia Webb
Published 2013-04-08 by SAE International in United States
Government agencies like EPA play an important role through regulation to reduce emissions and fuel consumption and to drive technological developments to reduce the environmental impact of burning petroleum fuels. Emissions testing and control is one of the leading and growing fields in the development of modern vehicles. Recently, Cummins Emissions Solutions (CES) and Southwest Research Institute (SwRI) worked jointly in order to achieve a method to conduct emissions testing efficiently and effectively. The collaborative work between the two organizations led to the usage of FOCAS HGTR™ (a diesel-based burner test rig at SwRI) to simulate the exhaust conditions generated by a 2010 ISX Cummins production engine operating over an EPA standard Ramped Modal Cycle Supplemental Emissions Test (RMC SET) cycle. The diesel-fueled HGTR burner rig went through a series of developments and modifications to permit the system to run quasi-transient control and enable it to simulate RMC SET cycles similar to an ISX engine. This paper discusses different aspects of this work.
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Modeling of Dual Layer Ammonia Slip Catalysts (ASC)

Cummins Inc-Bhargav Ranganath, Abhijeet Nande, Tamas Szailer
Johnson Matthey ECT-Balaji Sukumar, Jianguo Dai, Asa Johansson, Penelope Markatou
Published 2012-04-16 by SAE International in United States
In recent years, ammonia slip catalysts (ASC) are being used downstream of an SCR system to minimize the ammonia slip. The dual-layer ASC is more attractive for its bi-functionality in reducing the ammonia and NOX emissions. It consists of two layers with the upper layer comprising a component with SCR functionality and the lower layer a PGM containing catalyst with oxidation functionality. Thus, both oxidation and SCR reactions take place in two different layers and are interlinked by the inter-layer mass transfer mechanism. In addition, adsorption and desorption kinetics between the gas and solid phases play a significant role. Mathematically, the overall system is a complex system of mass, momentum and energy transfer equations with temporal and spatial variables in both axial and radial directions. In this work, we focus on devising a suitable, computationally inexpensive model for such ASCs to be efficiently used for design, control and system optimization studies. We discuss a 1D+1D (Pseudo 2D) model capturing the above-mentioned mechanisms to different extents and investigate the accuracy of the model in both steady…
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Investigation of the Impact of Real-World Aging on Diesel Oxidation Catalysts

SAE International Journal of Engines

Cummins Inc.-Junhui Li, Tamas Szailer, Ana Watts, Neal Currier, Aleksey Yezerets
  • Journal Article
  • 2012-01-1094
Published 2012-04-16 by SAE International in United States
Real-world operation of diesel oxidation catalysts (DOCs), used in a variety of aftertreatment systems, subjects these catalysts to a large number of permanent and temporary deactivation mechanisms. These include thermal damage, induced by generating exotherm on the catalyst; exposure to various inorganic species contained in engine fluids; and the effects of soot and hydrocarbons, which can mask the catalyst in certain operating modes. While some of these deactivation mechanisms can be accurately simulated in the lab, others are specific to particular engine operation regimes.In this work, a set of DOCs, removed from prolonged service in the field, has been subjected to a detailed laboratory study. Samples obtained from various locations in these catalysts were used to characterize the extent and distribution of deactivation. The arsenal of techniques used to characterize the samples included probe reactions of NO and C₃H₆ oxidation, as well as a set of pre-treatment conditions, targeting at removing various contaminants, including hydrocarbons, soot, sulfur, and phosphorous.
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Why Cu- and Fe-Zeolite SCR Catalysts Behave Differently At Low Temperatures

SAE International Journal of Fuels and Lubricants

Cummins Inc.-Krishna Kamasamudram, Neal Currier, Tamas Szailer, Aleksey Yezerets
  • Journal Article
  • 2010-01-1182
Published 2010-04-12 by SAE International in United States
Cu- and Fe-zeolite SCR catalysts emerged in recent years as the primary candidates for meeting the increasingly stringent lean exhaust emission regulations, due to their outstanding activity and durability characteristics. It is commonly known that Cu-zeolite catalysts possess superior activity to Fe-zeolites, in particular at low temperatures and sub-optimal NO₂/NOx ratios. In this work, we elucidate some underlying mechanistic differences between these two classes of catalysts, first based on their NO oxidation abilities, and then based on the relative properties of the two types of exchanged metal sites. Finally, by using the ammonia coverage-dependent NOx performance, we illustrate that state-of-the-art Fe-zeolites can perform better under certain transient conditions than in steady-state.
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Advanced Catalyst Solutions for Hydrocarbon Emissions Control During Rich Operation of Lean NOx Trap Systems

Cummins Inc-Tamas Szailer, Neal Currier, Aleksey Yezerets, Bradlee J. Stroia
Johnson Matthey PLC-Paul Millington, Hai-Ying Chen, Howard S. Hess
Published 2009-04-20 by SAE International in United States
The operation of NOx Adsorber catalysts (NAC), also often referred to as Lean NOx Trap catalysts or NOx Storage-reduction catalysts, entails frequent periodic NOx regeneration events. These are accomplished by creating a net reducing, fuel-rich environment in the exhaust. The reduction of hydrocarbon emissions which occur during such fuel-rich events is challenging, due to the oxygen-deficient environment. In order to overcome this limitation, two possibilities exist: (i) oxygen can be stored during lean phase, to be used for hydrocarbon slip oxidation in the subsequent rich phase, or (ii) unreacted hydrocarbons can be trapped during the rich phase and oxidized during the following lean phase. In this work, two groups of catalytic solutions were developed and evaluated for hydrocarbon emission control based on these approaches: an Oxygen Storage Compound (OSC) based catalyst and zeolite-based hydrocarbon trap catalyst.The experimental evaluation of these two approaches included several stages. The initial concept demonstration was focused on comparing powder samples against a reference oxidation catalyst, using a simplified laboratory screening protocol. Following that, a series of monolith-coated samples with various…
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