NGK Automotive Ceramics United States Inc.

Novi, MI, United States

NGK Automotive Ceramics United States Inc.

Novi, MI, United States
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Ito M.,Ngk Insulators | Katsube F.,Ngk Insulators | Hamada Y.,Ngk Insulators | Ishikawa H.,Ngk Insulators | Asako T.,NGK Automotive Ceramics United States Inc.
SAE Technical Papers | Year: 2017

Particle Number (PN) regulation was firstly introduced for European light-duty diesel vehicles back in 2011[1]. Since then, PN regulation has been and is being expanded to heavy-duty diesel vehicles and non-road diesel machineries. PN regulation will also be expanded to China and India around 2020 or later. Diesel Particulate Filter (DPF) is significant factor for the above-mentioned PN regulation. This filter technology is to be continuously evolved for the near future tighter PN regulation. Generally, PN filtration performance test for filter technology development is carried out with chassis dynamometer, engine dynamometer or simulator [2]. This paper describes a simplified and relatively quicker alternative PN filtration performance test method for accelerating filter technology development compared to the current test method. Point to be noted is that Soot Generator (SG), which is a diesel fuel burner and was originally developed for accelerated soot loading on DPF, is utilized establishing the alternative PN filtration performance test method. SG is proposed for particle source for the alternative test, which allows particle size distribution to be similar to actual vehicles. Another point is estimation of PN emission test result with actual vehicle by simulating the stage of early filtration where most of the PN leaks through the filter as it occurs on PN emission test with actual vehicle with cold-start condition which are pre-conditioning and soaking. The result shows high correlation with the PN test on each vehicle and testing cycle. Hence, the alternative PN filtration performance test method is acceptably applicable, as much quicker test method, in continuous filter technology evolution. Copyright © 2017 SAE International.


Asako T.,NGK Automotive Ceramics United States Inc. | Kai R.,NGK Automotive Ceramics United States Inc. | Toyoshima T.,NGK Automotive Ceramics United States Inc. | Vogt C.,NGK Europe GmbH | And 2 more authors.
SAE Technical Papers | Year: 2016

Ammonia Selective Catalytic Reduction (SCR) is adapted for a variety of applications to control nitrogen oxides (NOx) in diesel engine exhaust. The most commonly used catalyst for SCR in established markets is Cu-Zeolite (CuZ) due to excellent NOx conversion and thermal durability. However, most applications in emerging markets and certain applications in established markets utilize vanadia SCR. The operating temperature is typically maintained below 550°C to avoid vanadium sublimation due to active regeneration of the diesel particulate filter (DPF), or some OEMs may eliminate the DPF because they can achieve particulate matter (PM) standard with engine tuning. Further improvement of vanadia SCR durability and NOx conversion at low exhaust gas temperatures will be required in consideration of future emission standards. A high-porosity substrate (HPS) with increased vanadia catalyst loading is a viable solution to reach higher conversion efficiency targets at low exhaust temperatures (<300°C). A previous study evaluated HPS of various design configurations with a high vanadia catalyst loading with a gas reactor and an on-highway 7L class engine [1]. The study demonstrated HPS with high vanadia catalyst loading improves NOx conversion and has a potential to be downsized more than 50% when compared to standard substrate with conventional catalyst loading. This study addresses hydrothermally aged SCR performance of high vanadia catalyst loading on HPS in various design configurations. The catalyzed substrates were hydrothermally aged for 100 hours at 550°C with the engine and evaluated by measuring NH3 storage and performance over steady state conditions and the World Harmonized Transient Cycle (WHTC). For the transient test, 50% volume SCR was also tested to clarify effect of downsizing. The comparison of degreened and aged SCR performance confirms that HPS with high vanadia catalyst loading maintains high NOx conversion activity after 100 hours aging at 550°C even when the volume is cut in half. Also, the best SCR design in terms of tailpipe NOx and N2O emission is discussed in anticipation of tighter NOx and greenhouse gas emission (GHG) regulation. Copyright © 2016 SAE International.


Hirose S.,Ngk Insulators | Yamamoto H.,Ngk Insulators | Suenobu H.,Ngk Insulators | Sakamoto H.,Ngk Insulators | And 5 more authors.
SAE International Journal of Materials and Manufacturing | Year: 2014

Today the Ammonia Selective Catalytic Reduction (SCR) system with good NOx conversion is the emission technology of choice for diesel engines globally. High NOx conversion SCR systems combined with optimized engine calibration not only address the stringent NOx emission limits which have been introduced or are being considered for later this decade, but also reduce CO2 emissions required by government regulations and the increase in fuel economy required by end-users. Reducing the packaging envelope of today's SCR systems, while retaining or improving NOx conversion and pressure drop, is a key customer demand. High SCR loadings ensure high NOx conversion at very low temperatures. To meet this performance requirement, a High Porosity Substrate which minimizes the pressure drop impact, was introduced in SAE Paper 2012-01-1079 [1], [2], [3]. The High Porosity Substrate with an equivalent catalyst amount demonstrated a pressure drop reduction in SCR substrate against the baseline conventional substrate. Moreover, high porosity substrate with high catalyst amount shows a possibility to achieve high NOx conversion and significant downsizing. As previously proven [4], [5], [6], High Cell Density is an effective way to increase catalyst surface area and NOx conversion at high temperatures due to the mass transfer effect. A High Porosity, High Cell Density Substrate has been developed which offers a notable improvement in NOx conversion over a wide temperature range as well as SCR substrate volume reduction. This paper will define the concept and SCR NOx conversion performance of the new High Porosity with High Cell Density Substrate compared to conventional substrate. The evaluation also includes pressure drop, durability, and potential SCR downsizing. © 2014 SAE International.


Fujii S.,NGK Automotive Ceramics United States Inc. | Asako T.,NGK Ceramics United States Inc. | Yuuki K.,Ngk Insulators
SAE Technical Papers | Year: 2010

To evaluate various Diesel Particulate Filter (DPF) efficiently, accelerated tests are one of effective methods. In this study, a simulator composed by diesel fuel burners is proposed for fundamental DPF evaluations. Firstly particle size distribution measurement, chemical composition and thermal analysis were carried out for the particulate matter (PM) generated by the simulator with several combustion conditions. The PMs generated by specific conditions showed similar characteristics to PMs of a diesel engine. Through these investigations, mechanism of PM particle growth was discussed. Secondly diversified DPFs were subjected to accelerated pressure drop and filtration efficiency tests. Features of DPFs could be clarified by the accelerated tests. In addition, the correlation between DPF pressure drop performance and PM characteristics was discussed. Thirdly regeneration performance of the simulator's PM was investigated. The PM oxidation occurred intensively at lower temperature than that of an engine. The pressure drop of the simulator's PM was higher than that of an engine. These differences between the simulator and engine might be almost explained by PM characteristics investigated in this study. © 2010 SAE International.


Dimou I.,Massachusetts Institute of Technology | Sappok A.,Massachusetts Institute of Technology | Wong V.,Massachusetts Institute of Technology | Fujii S.,NGK Automotive Ceramics United States Inc. | And 4 more authors.
SAE Technical Papers | Year: 2012

Diesel particulate filters (DPF) are a common component in emission-control systems of modern clean diesel vehicles. Several DPF materials have been used in various applications. Silicone Carbide (SiC) is common for passenger vehicles because of its thermal robustness derived from its high specific gravity and heat conductivity. However, a segmented structure is required to relieve thermal stress due to SiC's higher coefficient of thermal expansion (CTE). Cordierite (Cd) is a popular material for heavy-duty vehicles. Cordierite which has less mass per given volume, exhibits superior light-off performance, and is also adequate for use in larger monolith structures, due to its lower CTE. SiC and cordierite are recognized as the most prevalent DPF materials since the 2000's. The DPF traps not only combustible particles (soot) but also incombustible ash. Ash accumulates in the DPF and remains in the filter until being physically removed. Several studies have confirmed that a small amount of ash accumulation in the DPF (until a certain level) improves DPF performance, both in terms of filtration efficiency and sooted back pressure [1, 2, 3, 4]. On the other hand, it has also been confirmed that too much ash accumulation increases exhaust back pressure, leading to a reduction in engine efficiency, as the ash occupies space and plugs the DPF. In some cases, periodic ash cleaning, which requires removal of the DPF from the vehicle, is needed to ensure appropriate DPF performance, especially for heavy-duty diesel vehicles which accumulate high mileage. Thus, accumulation of ash in the DPF is a common and considerable issue for long-term vehicle operation, regardless of the filter material. Improved understanding of the phenomena of ash accumulation in the DPF is valuable for further improvement of the emission-control system. In this study, four different non-catalyzed DPF materials (three different porosities and two different pore sizes) of rectangular configuration 38mm × 38mm × 152mm, made of SiC were subjected to accelerated ash loading. In addition, a non-catalyzed cordierite DPF was also evaluated to determine the influence of the DPF material. Ash loading at five different levels from 0 to 20 g/L was conducted. Twenty five ashed DPF samples in total were prepared for this investigation. The DPF back pressure response to soot loading was verified by a soot generator for all samples. The phenomenon of ash accumulation and its effects on the sooted DPF back pressure response was investigated, resulting in the formulation of DPF design criteria to reduce ash-related impact on lifetime DPF performance. Copyright © 2012 SAE International.


Hirose S.,Ngk Insulators | Miyairi Y.,Ngk Insulators | Katsube F.,Ngk Insulators | Yuuki K.,Ngk Insulators | And 3 more authors.
SAE Technical Papers | Year: 2012

Ammonia Selective Catalytic Reduction (SCR) and Lean NOx Trap (LNT) systems are key technologies to reduce NOx emission for diesel on-highway vehicles to meet worldwide tighter emission regulations. In addition DeNOx catalysts have already been applied to several commercial off-road applications. Adding the DeNOx catalyst to existing Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF) emission control system requires additional space and will result in an increase of emission system back pressure. Therefore it is necessary to address optimizing the DeNOx catalyst in regards to back pressure and downsizing. Recently, extruded zeolite for DeNOx application has been considered. This technology improves NOx conversion at low temperature due to the high catalyst amount. However, this technology has concerned about strength and robustness, because the honeycomb body is composed of catalyst. A zeolite catalyst supported by a ceramic honeycomb structure resolves the strength and robustness issues. Also the honeycomb structure offers higher geometric surface area (GSA), a key characteristic for higher NOx conversion. Cordierite substrates with a honeycomb structure are a historically proven technology used for a variety of applications (gasoline, diesel, LDV, HDV, Non-Road) over the past 30 years. Cordierite substrates have been used widely for three-way catalyst (TWC) and DOC as well as ammonia SCR and LNT for several decades. However, today's DeNOx catalyst technologies require higher catalyst loading to ensure very high conversion efficiencies at lower temperature. Conventional cordierite substrate has not been optimized for high catalyst loadings for DeNOx catalysts applications. By modifying cordierite substrate material properties for high catalyst loadings, lower pressure drop and retention of high NOx conversion efficiency can be offered. In this investigation, the performances of newly developed cordierite substrates with material properties adjusted to address high catalyst loadings and in various geometrical configurations were compared to conventional substrate technology. The performance evaluation includes NOx conversion, pressure drop performance, as well as durability and material strength evaluation. The paper will discuss the opportunities this newly developed material provides in regards to compactness and low pressure drop while maintaining high NOx conversion efficiency. Copyright © 2012 SAE International.


Kawakami A.,Ngk Insulators | Fukumi Y.,Ngk Insulators | Ito M.,Ngk Insulators | Sokawa S.,Ngk Insulators | And 5 more authors.
SAE Technical Papers | Year: 2016

Honeycomb substrates are widely used to reduce harmful emissions from gasoline engines and are exposed to numerous thermal shocks during their lifetime making thermal shock resistance one of the key factors in designing honeycomb substrates. More stringent emission regulations will require the honeycomb substrates to be lighter in weight to improve light-off performance and to have better thermal shock resistance than conventional honeycomb substrates to handle higher expected temperature gradients. Thermal shock resistance is generally evaluated on a substrate by evaluating the thermal strain caused by temperature gradients inside the substrate during durability testing [1,2]. During the test, a heated substrate is cooled at a surface face to generate temperature gradients while the temperature inside the honeycomb substrate is monitored by multiple thermocouples. Next generation lighter weight substrates have equal or lower thermal capacity than the installed thermocouples causing the measurement to show a slower temperature change than the actual substrate and would, therefore, misrepresent the thermal shock resistance. This paper describes a new evaluation method for thermal shock resistance of honeycomb substrates. It uses a newly developed analysis method which can eliminate the delay in measurement response by thermocouples. The method consists of experimenting with a thermal imaging camera and thermocouples and data analysis, taking into account the heat capacity and thermal conduction of honeycomb substrates and thermocouples. This method enables the calculation of the rapid thermal behavior of lighter weight substrates. © 2016 SAE International.


Kai R.,NGK Automotive Ceramics United States Inc. | Asako T.,NGK Automotive Ceramics United States Inc. | Toyoshima T.,NGK Automotive Ceramics United States Inc. | Vogt C.,NGK Automotive Ceramics United States Inc. | And 2 more authors.
SAE Technical Papers | Year: 2016

Ammonia Selective Catalytic Reduction (SCR) is a key emission control component utilized in diesel engine applications for NOx reduction. There are several types of SCR catalyst currently in the market: Cu-Zeolite, Fe-Zeolite and Vanadia. Diesel vehicle and engine manufacturers down select their production SCR catalyst primarily based on vehicle exhaust gas temperature operation, ammonia dosing strategy, fuel quality, packaging envelope and cost. For Vanadia SCR, the operating temperature is normally controlled below 550oC to avoid vanadium sublimation. In emerging markets, the Vanadia SCR is typically installed alone or downstream of the DOC with low exhaust gas temperature exposure. Vanadia SCR is also utilized in some European applications with passive DPF soot regeneration. However, further improvement of Vanadia SCR NOx conversion at low exhaust gas temperatures will be required to meet future emission regulations (i.e.: HDD Phase 2 GHG). A High-Porosity Substrate with increased Vanadia catalyst loading is a viable solution to achieve higher conversion efficiency targets at low exhaust temperatures (< 300oC). Previously, a study about High-Porosity Substrates with high Cu-Zeolite catalyst loadings demonstrated higher NOx conversion, as well as a potential for 50% reduction in SCR substrate volume when compared to the baseline, conventional substrates and catalyst loadings. In addition, the study found High Cell Density enhanced NOx conversion over a wide exhaust temperature range [1]. In this study, High-Porosity Substrate of various design configurations with a high Vanadia catalyst loading were initially evaluated on a gas reactor, from which several candidates were down selected for further evaluation on an engine bench test. These results are presented in this paper. © Copyright 2016 SAE International.


Fujii S.,NGK Automotive Ceramics United States Inc. | Asako T.,NGK Ceramics United States Inc.
SAE Technical Papers | Year: 2010

Ash accumulation is a considerable factor for long-term Diesel Particulate Filter (DPF) performance. Ash accumulation reduces the open frontal area (OFA) and plugs the surface pores. As a result, DPF back pressures with no soot (hereinafter "initial DPF back pressure") rise. At the same time, DPF back pressures with soot (hereinafter "sooted DPF back pressure") fall [ 1, 2, 3, 4 ]. Then sooted DPF back pressures rise after the reductions of the certain ranges [ 1, 3, 4 ]. It is known that DPF back pressure behaviors change variously by ash loading like this. The understanding of DPF back pressure behaviors with ash accumulation is indispensable for proper after-treatment system management. Ash accumulation progresses slowly and gradually in DPF while using of vehicles. Because of the slowness, the field surveys require a few years at least. To evaluate the effects within shorter terms, various accelerated test methods (ex. burning of lubricant oil [ 3, 4 ], mixing of lubricant oil in fuel [ 5, 6 ], and introduction of lubricant oil mist in intake air [ 7, 8 ]) have been reported as alternative test methods. The test periods require a couple of months because the accelerations of those test methods were restricted by consumption rate of lubricant oil. An artificial ash accelerated accumulation (AAAA) test was attempted for drastic shortening of the test periods. This paper describes the procedures and results obtained by the attempt. The results are compared with literature and the validity of proposed test method is discussed. Copyright © 2010 SAE International.


Fujii S.,NGK Automotive Ceramics United States Inc. | Asako T.,NGK Ceramics United States Inc.
SAE Technical Papers | Year: 2011

Back pressure of Diesel Particulate Filter (DPF) varies with accumulation of soot and/or ash. Soot can be cleaned in a high temperature oxidation (regeneration) process. But ash which is incombustible particulate matter derived from lubricant oil, engine wear, etc. cannot be cleaned from DPF without mechanical ash removal process and influences the back pressure perpetually. Design and control of DPF involving variation of the back pressure with ash accumulation will provide further improvement of fuel consumption and reliable operation in extended vehicle life time. Nevertheless, empirical investigations concerning ash accumulation are few because of the long testing time due to the slow accumulation rate, i.e. 0.5 - 2mg/mile [19]. In this investigation, four different designs of Cordierite (Cd) DPF were subjected to an accelerated ash accumulation test which is utilizing artificial ash powder. DPF back pressure with soot loading (sooted back pressure) was measured at several times during the ash loading progress, and influences of DPF design factors on sooted back pressure with ash were evaluated. After these measurements, the samples were dissected for observation of ash distribution. Furthermore, these DPF sooted back pressure behaviors were compared with those of DPF made of Silicone Carbide (SiC) which had obtained in the past investigation [2]. DPF design optimization from view point of back pressure with ash is discussed through the experimental results and comparisons. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

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