Honeycomb with varying channel size

Abstract

A honeycomb structure which includes an inlet end and an outlet end opposing each other and a plurality of cell channels extending along an axis from the inlet end to the outlet end, the cell channels having different hydraulic diameters and being arranged in a checkerboard pattern between large-diameter and small-diameter cell channels, and an extrusion die for making the same.

What is claimed is:  
     
         1 . A honeycomb structure comprising: 
 an inlet end and an outlet end opposing each other;    a plurality of cell channels extending along an axis from the inlet end to the outlet end,    wherein the cell channels have different hydraulic diameters and are arranged in a checkerboard pattern between large-diameter and small-diameter cell channels.    
     
     
         2 . The honeycomb in accordance with  claim 1  wherein the large channels have a hydraulic diameter 1.1-2 times larger than the small channels.  
     
     
         3 . The honeycomb in accordance with  claim 2  wherein the large channels have a hydraulic diameter 1.3 times larger than the small channels.  
     
     
         4 . A ceramic filter for trapping and combusting diesel exhaust particulates, the filter comprising a honeycomb body, the honeycomb body comprising: 
 an inlet end;    an outlet end opposite the inlet end;    a plurality of parallel cell channels extending in an axial direction between the inlet and outlet end, the plurality of cell channels having thin porous walls, the plurality of cell channels comprising: 
 a group of outlet cell channels each end-plugged at the inlet end and open and the outlet end;  
 a group of inlet cell channels each open at the inlet end and end-plugged at the outlet end, the inlet channels having a larger hydraulic diameter than the outlet channels;  
 wherein each inlet channel adjoins an outlet channel in a vertical direction and in a horizontal direction, such that inlet channels and outlet channel alternate across the honeycomb body.  
   
     
     
         5 . A ceramic filter in accordance with  claim 4  wherein the inlet channels have a hydraulic diameter 1.1-2 times larger than the outlet channels.  
     
     
         6 . A ceramic filter in accordance with  claim 5  wherein the inlet channels have a hydraulic diameter 1.3 times larger than the outlet channels.  
     
     
         7 . A ceramic filter in accordance with  claim 5  which is made of cordierite.  
     
     
         8 . A ceramic filter in accordance with  claim 5  which is made of silicon carbide.  
     
     
         9 . A method of removing particulates from an exhaust gas, the method comprising passing the exhaust gas through the open inlet cell channels at the inlet end of filter of  claim 4 , through the cell walls, and out of the honeycomb through the open outlet cell channels at the outlet end, whereby the particulates are removed from the exhaust gas and retained on the honeycomb filter.  
     
     
         10 . A honeycomb extrusion die comprising a die body, the die body comprising: 
 an inlet face,    a discharge face opposite the inlet face,    a plurality of feedholes extending from the inlet face into the body,    an intersecting array of discharge slots extending into the body from the discharge face to connect with the feed holes at feed hole/slot intersections within the die,    the intersecting array of discharge slots being formed by side surfaces of a plurality of pins of two different cross sectional areas forming a checkerboard matrix of pins alternating in size.    
     
     
         11 . The honeycomb extrusion die according to  claim 10  wherein pins have a square cross section.