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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

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. Source

Kawakami A.,Ngk Insulators | Mizutani T.,Ngk Insulators | Shibagaki Y.,Ngk Insulators | Yuuki K.,Ngk Insulators | And 6 more authors.
SAE Technical Papers

Diesel engines are more fuel efficient due to their high thermal efficiency, compared to gasoline engines and therefore, have a higher potential to reduce CO2 emissions. Since diesel engines emit higher amounts of Particulate Matter (PM), DPF systems have been introduced. Today, DPF systems have become a standard technology. Nevertheless, with more stringent NOx emission limits and CO2 targets, additional NOx emission control is needed. For high NOx conversion efficiency, SCR catalysts technology shows high potential. Due to higher temperature at the close coupled position and space restrictions, an integrated SCR concept on the DPFs is preferred. A high SCR catalyst loading will be required to have high conversion efficiency over a wide range of engine operations which causes high pressure for conventional DPF materials. Therefore, a high porosity DPF design has been developed to overcome the trade off between high pressure drop, high wash coat loadings, and sufficient filtration efficiency. Furthermore, the DPF design has been adjusted to a high ash capacity concept. This paper will describe the high porosity DPF material development, including test results and future outlook. Copyright © 2012 SAE International. Source

Saito C.,Ngk Insulators | Nakatani T.,Ngk Insulators | Miyairi Y.,Ngk Insulators | Yuuki K.,Ngk Insulators | And 7 more authors.
SAE Technical Papers

Gasoline Direct Injection (GDI) engines achieve better fuel economy but have the drawback of increased Particulate Matter (PM) emissions. As known from diesel engine applications particulate filters are an effective PM reduction device which is expected to be effective for reduction of particulates emitted by GDI engines as well. For this investigation new filter concepts especially designed for GDI applications are proposed. Filtration efficiency, pressure drop and regeneration performance were verified by cold flow bench and engine and chassis dynamometer testing. The experimental data were used to discuss the validity of these new filter design concepts. Copyright © 2011 SAE International. Source

Shimoda T.,Ngk Insulators | Ito Y.,Ngk Insulators | Saito C.,Ngk Insulators | Nakatani T.,Ngk Insulators | And 9 more authors.
SAE Technical Papers

The automotive industry is currently evaluating the gasoline particulate filter (GPF) as a potential technology to reduce particulate emissions from gasoline direct injection (GDI) engines. In this paper, several GPF design measures which were taken to obtain a filter with lower pressure drop when compared to our previous concept [Ref. 1], will be presented. Based on engine test bench and vehicle test results, it was determined some soot will accumulate on the GPF walls, resulting in an increase in pressure drop. However, the accumulated soot will be combusted under high temperature and high O2 concentration conditions. In a typical vehicle application, passive regeneration will likely occur and a cycle of soot accumulation and combustion might be repeated in the actual driving conditions. Since the amount of soot trapped by the GPF on a GDI engine is significantly lower than a diesel particulate filter (DPF) on a diesel engine, a thin wall and low cell density filter concept is applicable for providing lower pressure drop without PM. The unique GDI-engine application characteristics allow for a new cell structure to be developed and applied to the GPF. Copyright © 2012 SAE International. Source

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