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Fundamental aspects of performance and regeneration of a porous ceramic particulate trap are described. Dimensionless correlations are given for pressure drop vs. flow conditions for clean and loaded traps. An empirical relationship between estimated particulate deposits and a loading parameter that distinguishes pressure drop changes due to flow variations from particulate accumulation is presented. Results indicate that trapping efficiencies exceed 90% under most conditions and pressure drop doubles when particulate accumulation occupies only 5% of the available void volume. Regeneration was achieved primarily by throttling the engine intake air. For various combinations of initial loading level, trap inlet temperature and oxygen concentration, it was found that regeneration rate peaked after 45 seconds from initiation.

Fundamental regeneration rate data of cellular ceramic particulate traps are presented. The data were obtained from systematic bench experiments using scaled traps and simulated engine conditions. The study was conducted over a wide range of parameters, covering scaled regeneration flow rates from subidle engine flow to full flow at rated engine conditions, trap inlet temperatures from 500 to 650°C, oxygen concentrations from 5 to 21%, and particulate accumulation levels in the trap from a pressure drop ratio (relative to the clean unit) of 2 to 60. The effect of each parameter on the maximum trap temperature and regeneration time is independently studied and described. Favorable regeneration conditions in terms of minimizing the energy requirements for regeneration and avoiding trap destruction are identified. Finally, it is illustrated that regeneration maps of this type can be applied to develop a control logic for an automatic regeneration system.