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A design of a Diesel1 particulate matter (PM) filter system for heavy duty vehicles is presented. The system consists of two ceramic catalyzed filters connected in parallel, so that one is in operation while the other one is in stand by or during regeneration. The regeneration (cleaning) process is carried out through the injection of a hot air flow in inverse direction to the filtering process. The air is heated by a thermal energy storage device (Thermal Inertia Device, TID). A catalytic washcoat reduces the carbon activation energy in order to incinerate the (PM) at lower temperature levels. The system has a control and monitoring electronic circuit based on a micro-controller.

A particulate aggregate model which takes place during the incomplete combustion of Diesel1 fuel in heavy duty engines is presented. An approximate analytical solution for the temperature field in a filter ceramic porous wall is presented. An alternative approach covering essential engineering problems is presented by means of a numerical simulation, which shows safety operational features of the proposed scheme. Some predicted performance of the filter ceramic traps are also presented.

Even though the use of ceramic traps has lost popularity during the last few years, mainly due to the severe problems encountred during thermal regeneration, advances in the design of combustion chambers, improvement of fuels and lubricants, higher injection pressures, etc., have made possible to re-think the concept of mechanical filtration of Diesel1 particulate matter (DPM). In this paper a system is presented to automatically filter DPM and regenerate the ceramic filters under less stringent conditions. The use of a catalytic layer permits to lower the soot (DPM) activation energy to some easier to handle temperature levels. A system is then proposed as a retro-fit for new and used engines with the aim to target mainly the large metropolitan areas, where passenger buses are used extensively.

The design of a small electric bus powered by batteries is underway at the Instituto de Ingeniería of the Universidad Nacional Autónoma de México (IIUNAM). It is intended that this vehicle, which will be capable of transporting 30 persons, eventually replace many of the gasoline powered “microbuses”, presently operating in the Mexico City Metropolitan Area (MCMA), where very high atmospheric pollution levels are present. The first prototype will be field tested in a 5 km loop of the University Campus. The bus will have a specially designed body featuring an aluminum structure and honeycomb sandwich paneling.

In an attempt to meet the 1994 Federal Emissions Standards issued by the U.S. Environmental Protection Agency (EPA), a conceptual design of a self regenerating Particulate Matter Filter System (PMFS), was developed and partially tested. Main objective of the PMFS was to achieve a high Particulate Matter (PM) collection efficiency, as well as to provide some economical means for self regeneration of the ceramic filters used as trapping media. Design characteristics and expected performance of the PMFS (still under development), as well as some operational difficulties, are described in detail.