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The following paper highlights the results of a vehicle emission improvement program with emphasis on two main points: In the initial phase, various combinations of Pd and Pt-based three-way catalyst technologies were evaluated on a TLEV and a LEV calibrated vehicle in order to generate ULEV exhaust gas levels. One goal in this portion of the study was to achieve technical equivalence between a viable Pd-based technology and a newly developed Pt-based technology. A combination of the Pd- and Pt-based technologies was able to meet the ULEV and part of the ULEV II regulations in the test vehicle after a catalyst aging cycle that resembles 50,000 miles of vehicle driving. In the later phase, a mathematical algorithm based on the original TLEV and LEV vehicle data was developed in order to conduct computer modeling of the exhaust gas aftertreatment system. This algorithm described the kinetic behavior of the individual catalysts over a broad range of reaction conditions.

Shoebox catalytic converter design to securely mount thinwall substrates with uniform mounting mat Gap Bulk Density (GBD) around the substrate is developed and validated. Computational Fluid Dynamic (CFD) analysis, using heat transfer predictions with and without chemical reaction, allows to carefully select the mounting mat material for the targeted shell skin temperature. CFD analysis enables to design the converter inlet and outlet cones to obtain uniform exhaust gas flow to achieve maximum converter performance and reduce mat erosion. Finite Element Analysis (FEA) is used to design and optimize manufacturing tool geometry and control process. FEA gives insight to simulate the canning process using displacement control to identify and optimize the closing speed and load to achieve uniform mat Gap Bulk Density between the shell and the substrate.