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This paper compares the emissions performance of four ultra thin wall ceramic substrates with standard wall thickness product on a chassis dynamometer for two different substrate volumes. This comparison helps establish performance trends and provides useful information for selection of substrates in designing catalytic converter systems. This experimental study tests and compares four ultra thin wall products (400/4, 600/3, 600/4, and 900/2) with a standard wall product (400/6.5) at two different substrate volumes. Engine bench aging is used to simulate typical aged conditions. Temperature data as well as second by second and bag emissions data for hydrocarbons, carbon monoxide and oxides of nitrogen were used to evaluate the relative performances of the substrates. The US FTP and US06 driving cycles were used as protocols for the comparison. Results suggest that lower bulk density and higher geometric surface area interact to lead to lower emissions.

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.

The use of lightweight materials to produce automotive glazing is being pursued by vehicle manufacturers in an effort to improve fuel economy. As glazing’s become thinner, reduced rigidity means that the critical flaw size needed to create fracture becomes much smaller due to increased strain under load or impact. This paper documents experiments focused on the impact performance of several alternative thin laminate constructions under consideration for windshield applications (including conventional annealed soda-lime glass as well as laminates utilizing chemically strengthened glass), for the purpose of identifying new and unique failure modes that result from thickness reduction. Regulatory impact tests and experiments that focused on functional performance of laminates were conducted. Given the increased sensitivity to flaw size for thin laminates, controlled surface damage was introduced to parts prior to conducting the functional performance tests.

In urban areas, particulate emission from diesel engines is one of the pollutants of most concern. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled, “Clean Diesel Vehicle Air Quality Project” has been initiated by NY City Transit under the supervision of NYSDEC and with active participation from several industry partners. Under this program, 25 NY City transit buses with DDC Series 50 engines have been equipped with continuously regenerating diesel particulate filter systems and have been operating with ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. These buses were evaluated over a 9 month period for operations, maintainability and durability of the particulate filter.

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.

Gasoline particulate filters (GPF) have become a standard aftertreatment component in Europe, China, and since recently, India, where particulate emissions are based on a particle number (PN) standard. The anticipated evolution of regulations in these regions towards future EU7, CN7, and BS7 standards further enhances the needs with respect to the filtration capabilities of the GPFs used. Emission performance has to be met over a broader range in particle size, counting particles down to 10nm, and over a broader range of boundary conditions. The requirements with respect to pressure drop, aiming for as low as possible, and durability remain similar or are also enhanced further. To address these future needs new filter technologies have been developed. New technologies for uncatalyzed GPF applications have been introduced in our previous publications.

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.

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 gasoline particulate filter (GPF) represents a practical solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as an essential technology in North America to meet the upcoming US EPA tailpipe emission regulation, as proposed in the “Multi-pollutant Rule for Model Year 2027”. The goal of this study was to introduce advanced, uncoated GPF products and measure their particulate mass (PM) reduction performance within the existing US EPA FTP vehicle testing procedures, as detailed in Code of Federal Regulations (CFR) part 1066. Various state-of-the-art GPF products were characterized for their microstructure properties with lab-bench checks for pressure drop and filtration efficiency, then pre-conditioned with an EPA-recommended 1500 mile on-road break-in, and finally were tested on an AWD vehicle chassis-dyno emissions test cell at both 25°C and -7°C ambient conditions.

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 first-principles molecular dynamics method based on density-functional theory (DFT). Also, the accuracy of the UA-QCMD 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.

Vehicle windshields typically include a black decorative pattern around their periphery and other regions. Examination of field failed parts has shown that windshields often break from impacts in these decoration zones; often with the fracture initiating from the decoration material itself. In this work, the effect of different glazing decoration materials on glass strength and laminate impact resistance was evaluated. The decoration materials investigated included traditional inorganic enamel frit, an organic ink, and a new enamel frit that is compatible with glass chemical strengthening. Ring-on-Ring strength tests were conducted and showed that inorganic enamel frit reduces strength of glass by over 50% compared to undecorated glass, while organic inks do not adversely affect strength. Tests of a newly developed decoration frit material, compatible for chemical strengthening processes, showed strength levels that were on par with undecorated, unstrengthened glass.

Gasoline particulate filter (GPF) is considered a suitable solution to meet the increasingly stringent particle number (PN) regulations for both gasoline direct injection (GDI) and multi-port fuel injection (MPI) engines. Generally, GDI engines emit more particulate matter (PM) and PN. In recent years, GDI engines have gained significant market penetration in the automobile industry owing to better fuel economy and drivability. In this study, an accelerated ash loading method was tested by doping lubricating oil into the fuel for a GDI engine. Emission tests were performed at different ash loads with different driving cycles and GPF combinations. The results showed that the GPF could significantly reduce particle emissions to meet the China 6 regulation. With further ash loading, the filtration efficiency increased above 99% and the effects on fuel consumption and backpressure were found to be limited, even with an ash loading of up to 50 g/l.

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.

Examination of field-fractured windshields was conducted for purposes of determining the principle fracture mechanisms experienced in-use. Samples for the study were gathered both in the United States (New York) and in Europe (France) to explore whether the primary causes of failure were similar for the different geographic regions. In total, over two hundred individual field-fractures were obtained and examined for the study. Detailed fracture analysis of the parts was performed, and multiple fracture mechanisms were identified and quantified. It was found that the two most frequently observed failure modes were common for both regions with the most frequent cause (~70%) of fractures being due to sharp contact of the exterior ply, while Hertzian cone cracking of the outer ply was the second leading cause (~20%). Several other modes were also identified. Given that sharp impact fracture was the dominant observed failure mode, a high-speed, sharp impact test method was developed.

As the official proposal for emission regulation Euro 7 has been released by European Commission, PN above 10nm is taken into consideration for the ultrafine particulate emissions control. The challenges of GPF filtration efficiency emerge for the light-duty manufactures to meet the future emission standards. In the present study, a China 6 compliant vehicle was tested to reveal its performance over the China 6 standards and potential to meet the upcoming Euro 7. Three GPF product types (Gen 1, Gen 2, and concept Gen 3) were mounted to the tested vehicle. WLTC tests were conducted on chassis dynamometer in laboratory as well as a self-designed aggressive cycle (“Base Cycle”) tests. To explore the GPFs performance for PN emissions above 10nm against the proposed limit 6.0E11 #/km, PN emission above 10nm were measured in our laboratory tests for both engine out and tailpipe as well as the PN emission above 23nm.

RDE test has been introduced to the light-duty vehicle certification process in both China 6 and Euro 6d standards. The RDE test shall be performed on-road with PEMS, which is developed to complement the current laboratory certification of vehicles and ensure cars to deliver low emissions under more realistic on-road driving conditions. Particulate matter has been highly perceived as a significant contributor to human health risks and thus strictly regulated globally. For the RDE evaluation, the MAW method used by the China 6 standard is usually found less stringent than the RMA method used by the Euro 6d standard. In the present study, both of the MAW and RMA methods were applied to different driving cycles and operating conditions, which met the general RDE test requirements, yet resulted in different evaluated PN results.

Governing bodies world-wide are setting increasingly tighter emission standards to help improve air quality. US and Californian LEV/ULEV standards are pace setting, European Stage II legislation has just become effective. In Brazil, the upcoming 1997 standards are also demanding for tighter emission control. The monolithic ceramic honeycomb catalytic converter -for more than the past 20 years- has been a reliable key element in the automotive emission control systems. In order to help meet tightened emission regulation as well to satisfy even more stringent durability requirement, an advanced thinwall ceramic Celcor XT has been developed for increased geometric surface area and reduced backpressure. The product properties as well as FTP and ECE emission and durability test results are being described in this paper. Converter system durability is also determined by robust canning and mounting systems. A durable mounting concept, especially for preconverters, is being described.