Development of advanced particulate filters for automotive applications

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A combination of legislations is driving the need for improved fuel economy and reduced emissions. These require the use of new fuels and engine technologies that may increase, for example, particulate emissions. At the same time, tough new laws governing particulates are also being introduced, owing to concern over their health implications. In this research we will study the development of improved catalytic after-treatment systems that can be applied to diesel, gasoline and natural gas engines used in the transportation sector. The primary aspect of the emission system to be studied is the particulate filter, both with and without the combined functionality for the selective catalytic reduction (SCR) of NOX compounds. One significant new engine technology is gasoline direct injection (GDI), where the fuel is injected into the cylinder rather than the intake port, in a manner similar to diesel engines. Although this improves fuel economy, it also results in particulate matter in the emissions. These particles are different in several ways to the particulates emitted from diesel engines. Using a combination of experimental and sophisticated modelling techniques, we will study particle generation and capture in commercial filter material. These results will help us to understand the efficiencies of existing structures and their effect of the flow distribution at the microscopic level. The results will allow for better materials design of the filter. Another significant investigation is the effect of adding the NO reduction functionality directly into the filter by applying a catalytic washcoat to the filter substrate. There are a number of issues to be resolved relating to the overall structure and optimal washcoat distribution, which will lead ideally to the elimination of the separate deNOX reaction that is currently used.