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The adoption of head-up displays (HUDs) is increasing in modern automobiles. Yet integrating this technology into vehicles with standard windshield (WS) laminates can create negative effects for drivers, primarily due to the thickness of glass used. The double ghosting in HUD images is typically overcome by employing a wedged PVB between the two glass plies of the laminate. Another solution is to reduce the thickness of the glass without impacting the overall windshield toughness. Although this still requires the use of a wedged PVB to eliminate HUD ghosting, the thinner glass provides opportunity to increase the image size. However, reducing the thickness of a soda-lime glass (SLG) ply or plies in a conventional soda-lime glass (SLG) laminate can significantly impact the robustness of the laminate to external impact events.

Quantitative in-use pressure measurements were taken from packaging ceramic substrates with the SoftMountSM technology and two more traditional technologies, stuffing and tourniquet. Each technology was assessed using four separate mat materials. Mat selection enhanced the application of the SoftMountSM technology through the reduced pressures applied to the substrate during packaging. High temperature and low temperature thermal cycling studies were performed on the canned converters for the three packaging technologies so that an evaluation could be made of converter durability. The SoftMountSM packaging technology yielded the lowest pressures of all the processes studied, regardless of mat type. The laminar hybrid mat evaluated yielded the best combination of pressure and durability performance. Low temperature residual shear strengths following thermal cycling of the converters showed good correlation between the SoftMountSM technology and the stuffing method.

An analytical model for estimating shear and bending stresses during canning of cordierite ceramic catalyst supports is presented. These stresses arise when the radial pressure distribution is nonuniform due, primarily, to variations in gap bulk density (GBD ) of intumescent mat around the perimeter of the substrate. Variations in GBD can occur during canning, regardless of the canning technique, due to anisotropic can stiffness or component tolerances or mat overlap. The model helps relate shear and bending stresses to substrate size and orientation, elastic modulii, cell size and wall porosity. If these stresses approach the corresponding strength of substrate, a shear crack may develop during or after the canning process depending on the magnitude of stress. A special test fixture was developed to measure the shear strength of ceramic catalyst supports, with different cell sizes, before and after the application of washcoat.

The key diesel emission control papers of the last 12 months have been summarized. In addition, the emerging US and European light-duty and heavy-duty tailpipe regulations are compared. Results are reported on light-duty diesel filtration regeneration systems and experiences, including effects of ash build-up and some recent modeling work. On the heavy-duty side, optimization of SCR catalysts and systems are described, as well as experiences with the first integrated SCR/filter systems, which are already achieving “Euro V” 2008 standards. An update on NOx adsorbers is also provided. The results with new NOx formulations are described, as well as the system performance in a light-duty diesel application.

One approach to the remediation of NOx generated under lean automotive engine conditions is its controlled storage and then periodic release and reaction under enriched conditions. This process is being considered for automotive exhaust systems that will be operated pre–dominantly lean for reasons of fuel economy. Because of the special characteristics of alkali and alkaline earth elements in the presence of NOx, they are being considered for use, in conjunction with γ–alumina–based washcoats and precious metal catalysts, as NOx catalyst coatings on cellular supports. It is known that alumino–silicates will react with alkali and alkaline earth elements to form stable ceramic phases when mixtures of the components are held in direct contact at elevated temperatures.

With stricter emissions standards, low back pressure requirements, and 100,000 mile durability specifications, ceramic catalysts have undergone significant developments over the past few years. The thrust in the ceramics area has centered on thin-wall structures to minimize back pressure and on high cell density for rapid light-off in close-coupled applications. The thin-wall structures are extruded from low expansion cordierite ceramic with adequate strength and thermal shock resistance equivalent to those of standard cordierite substrate. Examples of thin-wall substrate include 350XT which is extruded from a very low expansion dense cordierite ceramic, and 400/4 and 600/4 cell structures extruded from a low expansion modified cordierite ceramic. This paper will focus on the high fatigue resistance, excellent conversion efficiency, and low back pressure of 350 XT substrates with advanced washcoat system.

The monolithic, large frontal area (LFA), extruded ceramic substrates for diesel flow-through catalysts offer unique advantages of design versatility, longterm durability, ease of packaging and low Cost [1, 2]*. This paper examines the effect of cell density and cell size on catalyst light-off performance, back pressure, mechanical and thermal durability, and the steady-state catalytic activity. The factors which affect these performance characteristics are discussed. Certain trade-offs in performance parameters, which are necessary for optimum systems design, are also discussed. Following a brief discussion of design methodology, substrate selection, substrate/washcoat interaction and packaging specifications, the durability data for ceramic flow-through catalysts are summarized. A total of over 18 million vehicle miles have been successfully demonstrated by ceramic LFA catalysts using the systems design approach.

Extruded metal honeycombs are used as electrically heated catalysts (EHCs). The durability requirements of this application make demands on high surface area, thin cross-section metal honeycombs. Significant durability improvements over previous extruded metal honeycomb EHCs have been achieved by material and package design changes. The product redesign was supported by finite element models and extensive testing. The redesigned EHC has passed severe laboratory and field testing. The tests include electrical cycling to 1000°C/1600 cycles, hot vibration to 60g/900°C and demanding on-vehicle exposure. Excellent durability of the extruded metal honeycomb has been demonstrated.

High temperature modulus of rupture (MOR) data, published previously, show that the ceramic catalyst supports get stronger with temperature due to the absence of water vapor and closure of microcracks which would otherwise act as stress concentrators [1, 2 and 3]*. The increased MOR value is partially responsible for the excellent durability of ceramic catalyst supports at high temperature. In this paper, we will present the compressive strength data of ceramic substrates at high temperature, namely the crush strength along B-axis and biaxial compressive strength of the whole substrate. Since the honeycomb strength is directly related to that of the individual cell wall, the compressive strength should also increase with temperature similar to the modulus of rupture. Accordingly, the ceramic substrates are capable of supporting higher mounting pressures exerted by the intumescent mat at high temperature [4].

The design, performance and optimization of the extruded electrically heated metal converter have recently been published(1,2). The present paper focuses on the physical durability of extruded metal EHC support at high temperature representative of operating conditions. The mechanical, thermal, creep and fatigue properties of Fe-Cr-Al honeycomb structure over 25°-1000°C temperature range are reported. In addition, the stresses arising from mounting and thermal loads are computed via finite element analysis and compared with the high temperature strength of extruded metal EHC support. A safe design stress which predicts 192,000 kilometer durability is estimated from high temperature fatigue behavior of extruded Fe-Cr-Al honeycomb structure.

The motorcycle emissions regulations for both two-stroke and four-stroke engines, which are receiving worldwide attention, will go into effect in the very near future. To meet these regulations, the motorcycles will require a catalyst in conjunction with the muffler due to space limitations. The combination of high engine speeds, high vibrational acceleration, high HC and CO emissions, high oxidation exotherms, and stringent durability requirements, points to cordierite ceramic substrate as an ideal catalyst support. However, as an integral unit within the muffler, its packaging design must be capable of withstanding isothermal operating conditions which may exceed the upper intumescent temperature limit of the ceramic mat. This paper describes a durable packaging design for the ceramic catalyst which employs a hybrid ceramic mat, special end rings and gaskets, and high strength stainless steel can.

The stringent durability requirements approaching 100,000 vehicle miles for automotive substrates and 290,000 vehicle miles for large frontal area diesel substrates for 1994+ model year vehicles call for advanced packaging designs with thick ceramic mats and high mount densities. The latter result in high mounting pressure on the substrate and enhance its mechanical integrity against engine vibrations, road shocks and back pressure forces. A novel measurement technique which applies a uniform biaxial compressive load on the lateral surface of ceramic substrates, thereby simulating canning loads, is described. The biaxial compressive strength data obtained in this manner help determine the maximum mounting pressure and mat density for a durable packaging design. The biaxial compressive strength data for both round and non round substrates with small and large frontal area are presented.

Improved designs of extruded metal electrically heated catalysts (EHC) in combination with a traditional converter achieved the California ultra-low emission vehicle (ULEV) standard utilizing 50% less electrical energy than previous prototypes. This energy reduction is largely achieved by reducing the mass of the EHC. In addition to energy reduction, the battery voltage is reduced from 24 volts to 12 volts, and the power is reduced from 12 kilowatts to 3 kilowatts. Also discussed is the impact EHC mass, EHC catalytic activity, and no EHC preheating has on non-methane hydrocarbon emissions, energy requirements, and power requirements.

Previous papers have considered the role of the substrate in the catalyst system. It has been shown that the total catalyzed surface area of the substrate (defined as the substrate geometric surface area multiplied by the substrate volume) can act as a surrogate for the catalyst performance. The substrate affects the back pressure of the exhaust system and therefore, the available power. Relationships have been developed between the substrate physical characteristics, and both the pressure drop and total surface area of the substrate. The substrate pressure drop has also been related to power loss. What has been lacking is a means of quantitatively relating the substrate properties to the conversion efficiency. This paper proposes a simple relationship between the substrate total surface area and the emissions of the vehicle as measured on the FTP cycle.