Patent ID: 8007557

Claim:
A particulate filter comprising a filter body comprised of a honeycomb structure of porous ceramic, the filter body comprising a cell density, N, and a wall thickness, w, the porous ceramic having a total pore volume fraction, p, and a median pore diameter, d 50 ; wherein the filter body is characterized by P c =0.156(w)+0.00632(N)+2.429(w)/[(d 50 2 )(p)], N is in units of cells (channels) per square inch, w is in units of 10 −3 inches (mils), p is dimensionless and equal to the total porosity in % (% porosity) divided by 100, d 50 is in units of microns, and d 50 and % porosity are as measured by mercury porosimetry, and P c ≦4.0; and wherein the filter body has: a d 50 ≦14 μm, a d 90 ≦20 μm, a room-temperature four-point modulus of rupture on an axial specimen of the honeycomb structure (MOR) of at least 200 psi, a ratio of MOR/CFA of at least 1100 psi, where CFA is the closed frontal area fraction of the face of the honeycomb substrate, defined as CFA=(w/1000)[2(N −0.5 )−(w/1000)](N); an elastic modulus ratio, E(900)/E(25), of not more than 0.97, where the value of E(900) is the elastic modulus at 900° C. as measured upon heating, and the value of E(25) is the elastic modulus as measured near room temperature prior to heating, both as measured on a bar parallel to the axial direction of the honeycomb, and a thermal shock limit, TSL(200)>800° C., defined as TSL(200)=200+(MOR/E)/[CTE(200-1000)] where MOR and E are as measured at room temperature and CTE(200-1000) is the mean coefficient of thermal expansion from 200 to 1000° C. as measured by dilatometry along the axial direction of the honeycomb.