[Purpose of Development]

The purpose of this technology development is to actualize an exhaust gas processor that contains a metal foam filter with catalyst for elimination of not only soot but also Soluble Organic Fraction (SOF) from the Paticulate Matter (PM) of diesel engine exhaust gas. Normally, SOF cannot be removed by means of the Diesel Paticulate Filter (DPF) and are released as exhaust gas. SOF are considered to include both carcinogenic and allergenic substances.

In concrete terms, we are trying to product DPF which can be used to reduce the total amount of PM emissions by accumulation and burning of soot and by addition of a catalytic function to the metal foam DPF.

[Goals of Development]

(1) To reduced PM emissions with greater than 80% efficiency when the SOF ratio is in the range of 40 to 50%.

(2) To achive a Pressure loss of 10kPa or less for 6g accumulated PM.

[Results]

(1) The diameters of the ?-alumina dispersion particles were reduced by pH adjustment, making it possible to form an uniform supported layer even inside the metal foam DPF.

(2) The adhesion of the supported layer was enhanced by the oxidation and gluing agents of the metal foam DPF.

(3) Based on the above developments, durability of the catalytic layer at 700? for 100hr has been realized.

(4) Technology to evaluate diesel engine exhaust gas components has been developed through introduction of an exhaust gas analyzer.

(5) Catalytic perfoamance was evaluated by analysis of exhaust gas before and after its passage through the intercalated metal foam DPF.

(6) The catalytic characteristics (T-HC and CO purification rates) of the metal foam are significantly affected by the average diameter and surface area ot the pores.

(7) Depending on metallic catalysts used, marked differences were observed in the dependences of the T-HC and CO purifi cation rates on the catalytic reaction temperature.

(8) Though SEM observation and elemental analysis, metallic catalysts were found to the intercalated in the form to be supported in the form of nanometer and micronmeter size particles. Catalytic performance can be expected to be enhanced uniform support of all of the metallic catalysts in the form of nanometer size ultra-fine particles.

[Future Development]

(1) Enhancement of uniformity and high-level dispersion of catalyst.

(2) Evaluation of catalyst dispersion conditions and clarification of the relationship between catalyst dispersion condition and catalytic performance.

(3) Optimization of the metallic catalysts.