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Regeneration experiments were carried out for the establishment of a particulate combustion model. Distributions of the filter temperature and gas temperature, the concentration of the oxygen in the filter, and combustion products were simultaneously measurd. Numerical simulations were performed by two steps. As the first step, a quasi one-dimensional simulation model was applied to the estimation of propagation characteristics of the particulate combustion, such as flame velocities, and the filter temperature change with time. Air velocity and heat capacity of the filter were found to be important factors for the combustion propagation. As the second step, a two-dimensional axisymmetric simulation program for the regenerative combustion was developed and coupled with a FEM stress analysis program “MARC”.

Regeneration capability of a wall-flow monolith type diesel paticulates filter with an electric heater was studied. To prevent filter crack generation and unburned particulates accumulation, a precision controller was added to the test equipment to reduce thermal load. In order to control the supply of oxygen to potentially prevent cracking, a second air feeder was also added. Furthermore, to ignite the accumulated particulates uniformly and propagate extensively to burn accumulated particulates completely a newly improved heater unit was employed. Repeated regeneration tests were conducted with cars on a chassis dynamometer. Though crack generation and unburned particulates accumulation were reduced considerably, satisfactory prevention could not be achieved. Therefore a parameter study using regenerative burning and thermal stress analysis model was carried out.