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A correlation of aerodynamic wind tunnels was initiated between Chrysler, Ford and General Motors under the umbrella of the United States Council for Automotive Research (USCAR). The wind tunnels used in this correlation were the open jet tunnel at Chrysler's Aero Acoustic Wind Tunnel (AAWT), the open jet tunnel at the Jacobs Drivability Test Facility (DTF) that Ford uses, and the closed jet tunnel at General Motors Aerodynamics Laboratory (GMAL). Initially, existing non-competitive aerodynamic data was compared to determine the feasibility of facility correlation. Once feasibility was established, a series of standardized tests with six vehicles were conducted at the three wind tunnels. The size and body styles of the six vehicles were selected to cover the spectrum of production vehicles produced by the three companies. All vehicles were tested at EPA loading conditions. Despite the significant differences between the three facilities, the correlation results were very good.

Asymmetric particulate filters (PF), where the inlet channel is wider than the outlet channel, are commonly used because of their greater capacity for ash. Somewhat surprisingly, very few models for asymmetric PFs have been published and none of these gives a correct/detailed description of the geometry. For example, octahedral channels may be treated as if they were square or the tapering walls between the inlet and outlet channels treated as if they were rectangular in cross section. Alternatively, the equations may be presented in generic form in terms of channel cross-sectional areas and perimeters, but without giving any indication of how to calculate these. This paper aims to address these deficiencies with a model that correctly describes the geometry of square and octo-square asymmetric PFs. Expressions for the solid fraction of the PF (which affects thermal mass) and channel cross section and perimeter (both when clean and soot/ash loaded) are presented.

Increasingly stringent vehicle emissions legislation is being introduced throughout the world, regulating the allowed levels of particulate matter emitted from vehicle tailpipes. The regulation may prove challenging for gasoline vehicles equipped with modern gasoline direct injection (GDI) technology, owing to their increased levels of particulate matter production. It is expected that gasoline particulate filters (GPFs) will soon be fitted to most vehicles sold in China and Europe, allowing for carbonaceous particulate matter to be effectively captured. However, GPFs will also capture and accumulate non-combustible inorganic ash within them, mainly derived from engine oil. Studies exist to demonstrate the impact of such ash on GPF and vehicle performance, but these commonly make use of accelerated ash loading methods, which themselves introduce significant variation.

Reduction of nitrogen oxides in Diesel exhaust gas is a challenging task. This paper reports results from an extensive study using Pt-based catalysts involving synthetic gas activity testing (SCAT), engine bench testing and tests on passenger cars. Preliminary SCAT work highlighted the importance of Pt-dispersion, and both SCAT and bench engine testing yielded comparable NOx conversions under steady state conditions at high HC:NOx ratios. On passenger cars in the European cycle without secondary fuel injection NOx conversion was lower than obtained in the steady state tests. Better conversion was obtained in the FTP cycle, where secondary injection was employed. Higher HC:NOx, ratios and more favourable temperature conditions which were present in the exhaust contributed to this higher conversion.

In the auto industry, lightweight window designs are drawing more attention for improved gas mileage and reduced exhaust emission. Corning’s Gorilla® Glass used in laminate design enables more than 30% weight reduction compared to conventional soda-lime glass laminates. In addition, Gorilla® Glass hybrid laminates (which are a laminate construction of a thick soda-lime glass outer play, a middle polyvinyl butyral interlayer, and a thin Gorilla Glass inner ply) also show significantly improved toughness due to advanced ion-exchange technology that provides high-surface compression. However, the reduced mass also allows increased transmission of sound waves through the windshield into the vehicle cabin. A system-level measurement approach has always been employed to assess overall vehicle acoustic performance by measuring sound pressure levels (SPL) at the driver’s ears. The measured sound signals are usually a superimposition of a variety of noise sources and transmission paths.

Enhancements in the thermal stability of three-way catalysts have been achieved by: 1) developing improved methods for the incorporation of ceria into catalyst formulations and 2) identifying a proprietary stabilizer which reduces the rate of ceria sintering at high temperature. Improvements in thermal stability are demonstrated by comparing the FTP and engine dynamometer performance of new formulations with a standard formulation after aging on several high temperature engine dynamometer cycles.

It has long been recognized that the key to achieving stringent emission standards such as ULEV is the control of cold-start hydrocarbons. This paper describes a new approach for achieving excellent cold-start hydrocarbon control. The most important component in the system is a catalyst that is highly active at ambient temperature for the exothermic CO oxidation reaction in an exhaust stream under net lean conditions. This catalyst has positive order kinetics with respect to CO for CO oxidation. Thus, as the concentration of CO in the exhaust is increased, the rate of this reaction is increased, resulting in a faster temperature rise over the catalyst.

A test programme has been conducted to study any potential long term effects of gasoline sulphur on catalyst performance, using a newly developed transient engine-bed ageing cycle. The ageing cycle, which was based on repeated European Extra Urban Drive Cycles, was chosen to ensure that the catalyst experienced a realistically wide range of temperatures and space velocities, together with transients, idle and periods of overrun. Two nominally identical platinum/rhodium catalysts (manufactured from the same batch) with matched lambda sensors, were aged for a period of 80,000 km each, one being aged using a gasoline containing 50 mg/kg (ppm wt) sulphur, the other being aged on the same fuel doped to 450 ppm wt S. The emissions performance of both catalysts was measured after 6,000, 40,000 and 80,000 km ageing, by fitting the catalysts to a test vehicle, and performing emissions tests over the European test cycle at both sulphur levels.

Internal combustion engines (ICEs) exhaust emissions, particularly nitrogen oxides (NOx), have become a growing environmental and health concern. The biggest challenge for contemporary ICE industry is the development of clean ICEs, and the use of advanced design tools like Computational Fluid Dynamics (CFD) simulation is paramount to achieve this goal. In particular, the development of aftertreatment systems like Selective Catalyst Reduction (SCR) is a key step to reduce NOx emissions, and accurate and efficient CFD models are essential for its design and optimization. In this work, we propose a novel 3D-CFD methodology, which uses a Machine Learning (ML) approach as a surrogate model for the SCR catalyst chemistry, which aims to enhance accuracy of the simulations with a moderate computational cost. The ML approach is trained on a dataset generated from a set of 1D-CFD simulations of a single channel of an SCR catalyst.

This paper describes the use of advanced three-way catalysts to meet future European and California low emissions legislation. Firstly, it describes the performance of these catalysts tested using the European Stage II test cycle and contrasts their emissions performance over the proposed European Stage III test. The future legislation requires fast catalyst light-off for the low emissions standards to be achieved, therefore the performance of close-coupled catalysts was investigated. The close-coupled catalyst systems gave very low emissions. Space constraints often preclude the use of large volume close-coupled catalysts, and the combination of a small starter catalyst with an underfloor catalyst was tested. This gave performance levels better than the close-coupled configuration. The effect of reducing the underfloor catalyst volume is also described. The work was carried out on a 1.2 litre European Vehicle, the conclusions were verified on a 1.6 litre European vehicle.

Various types of after-treatment system for BS VI Stage 1 are being assessed for the Light Duty Diesel (LDD) segment. For BS VI Stage 2, Real Driving Emission (RDE) assessment will be newly introduced, which will require more robustness in emission control system capability. Although the detailed requirements for India BS VI stage 2 are still being discussed, a reasonable assumption is that similar systems to those being developed for Euro 6d, will work for India BS VI. This paper describes typical system designs for Euro 6d and also reveals newly developed SCRF® (Selective Catalytic Reduction Filter) based systems, which demonstrate excellent RDE emissions. In addition, newly developed Lean NOx Trap (NSC) coatings, which focus on low temperature NOx control used with SCRF® (NSC + SCRF®) also show excellent emission control capability as demonstrated in this case on the ARTEMIS Cycle. These systems have potential as promising LDD solutions for India BS VI stage 2.

Diesel Oxidation Catalyst in conjunction with large frontal area substrates is a key element in HDV Diesel emission control systems. This paper describes and reviews tests on a set of various Diesel Oxidation Catalyst configurations (for example cell densities), all with the same catalyst coating. The Diesel Oxidation Catalyst specimens were subjected to the European Stationary Cycle (ESC), the European Transient Cycle (ETC), and the US heavy duty Federal Test Procedure (US FTP). The focus was to study relative emissions, pressure drop, and light-off performance. All tests were conducted using the same Detroit Diesel Series 60 engine operating on ultra low sulfur diesel fuel. In addition to this, the exhaust was regulated so that the backpressure on the engine, upstream of the catalyst was also the same for all catalysts.

A comparison of two different types of NOx reducing catalysts will be worked out. The potential of two De-NOx catalysts using engine out hydrocarbon emissions for NOx conversion will be shown by variation of different engine parameters. An analysis of the hydrocarbon species upstream and downstream catalyst will demonstrate, which components are responsible for the NOx reduction in the exhaust gas of a lean burn engine. By variation of different parameters during adsorbtion and regeneration phases of the adsorber catalyst the efficiency in NOx reduction will be optimized. An assessment of the suitability for lean burn engines will consider the emission reduction efficiency as well as the influence on engine fuel consumption.

The evolution toward the use of electrostatic painting processes has been driven primarily by environmental legislation and efforts to improve efficiencies in the painting process. The development of conductive substrate material compliments the industry trend toward a green environment through further reductions in emissions of volatile organic compounds during the painting process. Traditionally, electrostatic painting of thermoplastics requires that a conductive primer be applied to the substrate prior to topcoat application. The conductive polymer blend of polyphenylene ether and polyamide provides sufficient conductivity to eliminate usage of conductive primers. Additional benefits include improved transfer efficiencies of the primer and top coat systems, uniform film builds across the part, and improved painting of complex geometries.

Several predictive equations based on the chemical composition of gasoline have been shown to estimate the particulate emissions of light-duty, internal combustion engine (ICE) powered vehicles and are reviewed in this paper. Improvements to one of them, the PEISimDis equation are detailed herein. The PEISimDis predictive equation was developed by General Motor’s researchers in 2022 based on two laboratory gas chromatography (GC) analyses; Simulated Distillation (SimDis), ASTM D7096 and Detailed Hydrocarbon Analysis (DHA), ASTM D6730. The DHA method is a gas chromatography mass spectroscopy (GC/MS) methodology and provides the detailed speciation of the hundreds of hydrocarbon species within gasoline. A DHA’s aromatic species from carbon group seven through ten plus (C7 – C10+) can be used to calculate a Particulate Evaluation Index (PEI) of a gasoline, however this technique takes many hours to derive because of its long chromatography analysis time.

Stringent emissions standards with 95+% conversion efficiency requirements call for advanced ceramic catalyst supports with thinner walls, higher cell density and optimum cell shape. The extrusion technology for cellular ceramics has also made significant progress which permits the manufacture of advanced catalyst supports. Similarly, modifications in cordierite chemistry and the manufacturing process have led to improved microstructure from coatability and thermal shock points of view. The design of these supports, however, requires a systems approach to balance both the performance and durability requirements. Indeed as the wall gets thinner, the contribution of washcoat becomes more significant in terms of thermal mass, heat transfer, thermal expansion, hydraulic diameter and structural stiffness - all of which have an impact on performance and durability. For example, the thinner the wall is, the better the light-off performance will be.

The implementations of the Tier 2 and LEVII emission levels require fast catalyst light-off and fast closed loop control through high-speed engine management. The paper describes the development of innovative catalyst designs. During the development thermal and mechanical boundary conditions were collected and component tests conducted on test rigs to identify the emission and durability performance. The products were evaluated on a Super Imposed Test Setup (SIT) where thermal and mechanical loads are applied to the test piece simultanously and results are compared to accelerated vehicle power train endurance runs. The newly developed light-off catalyst with Perforated Foil Technology (PE) showed superior emission light-off characteristic and robustness.

This paper describes the development of new high performance three-way catalyst (TWC) formulations with improved activity and enhanced thermal stability. These new TWC formulations enable the converter to be fitted closer to the engine and allow this future legislation to be met with catalysts using PGM levels significantly lower than those currently being employed. The performance benefits of these advanced platinum- and palladium-based catalysts are demonstrated on a number of different vehicles after bench-engine ageing.

This paper will examine the regulatory development process, discuss the technical principles of the Economic Commission for Europe (ECE), R51.03 test, and discuss the overall objectives of the ECE R51.03 noise emission regulation. The development of this global noise emission regulation was a multi-stakeholder process which has resulted in new test procedures and new noise emission regulation principles. New test procedures based on ISO 362-1:2015 move the test basis to representative in-use noise emission, independent of vehicle propulsion technology. As part of the regulatory development, a monitoring program was conducted by the European Union to assess the applicability of the proposed test to provide representative vehicle noise emission results. The monitoring results also provided the basis to determine equivalent stringency between the test procedures of ECE R51.02 and R51.03.

A test method, based on parallel sample testing with exhaust fuel injection and certain test procedures, has been developed for diesel lean-NOx catalyst evaluation purposes. The results of the verification tests show uniform distribution of both the exhaust gas and the injected fuel, and a high degree of fuel evaporation. Test procedures are discussed from several points of view. The test method offers a precise and efficient way of testing lean-NOx catalysts on heavy duty diesel engines.