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Making use of fabric filtration in diesel particulate collection, a multi-bag particulate collection system for diesel buses was developed. Teats of the particulate collector prototype on a diesel engine dynamometer bench and an operating diesel bus showed that the collection system worked reliably with particulate collecting efficiency more than 90%.Further developmental work on the collection system is suggested.

A ceramic foam particulate trap for reducing automotive diesel engine particulate emission was developed. With its trapping efficiency 50-70 %, the trap is also reliable and durable. However, under practical automotive cruising conditions with exhaust temperature 400-650 K, particulates deposited in trap element cannot be burned up spontaneously to regenerate the element. The thermal regeneration temperature is 750-800 K. Adding organic compounds of copper, cerium or other metals in diesel fuel in concentrations 0.1-0.2 g/L (on the effective metal ion basis) reduces the regeneration temperature by about 100 K which is not enough to make the trap regenerate reliably in practical automotive application of particulate trap. A Simple diesel fuel burner developed regenerated the ceramic element completely in 1-3 minutes, providing a promising future for the practical utilization of the diesel particulate trap.

The paper consists of two parts. In the first part reported are the results of experimental physical characterization of a light duty IDI diesel engine exhaust particulate: concentrations, size distributions, and morphology. In the second part of the paper, presented is the development of a prototype particulate trap-oxidizer with ceramic foam as trapping element to reduce light-duty vehicle diesel engine exhaust particulate emission level. Tests of the trap-oxidiaer on the 485% diesel engine showed, ceramic foam trap reduced the diesel particulate emissions by 50-70% on the basis of mass concentrations. Trapped particulate deposits incinerates spontaneously when exhaust gas temperature over 450°C, reducing the resistance of the trap to exhaust flow. By the aid of fuel additives the regeneration temperature may he lowered by about 100°C.