Exhaust emission control device and casing structure of the control device

Abstract

An exhaust gas purifying device includes a tubular casing arranged in exhaust passages of an internal combustion engine. A filter is held in the casing. The filter collects and burns particulates contained in the exhaust gas discharged by the internal combustion engine. The casing has a double structure including an inner case supporting an outer peripheral surface of the filter and an outer case arranged around the inner case. The inner and outer cases are spaced from each other with a clearance defined between the cases.

1 . An exhaust gas purifying device for use with an engine having an exhaust passage, the exhaust gas purifying device comprising: 
 a tubular casing disposed in the exhaust passage of the engine and a filter accommodated in the casing for collecting, burning, and removing particulates contained in the exhaust gas discharged by the engine,    the casing having a multiple case structure including an inner case supporting an outer peripheral surface of the filter and at least one outer case arranged around the inner case, with the inner and outer cases being spaced from each other with and a clearance defined between the inner and outer cases.    
   
   
       2 . An exhaust gas purifying device for use with an engine having an exhaust passage, the exhaust as purifying device comprising: 
 a tubular casing disposed in the exhaust passage of the engine and a filter accommodated in the casing for collecting, burning, and removing particulates contained in the exhaust gas discharged by the engine,    the casing having a double case structure including an inner case supporting an outer peripheral surface of the filter and an outer case arranged around the inner case, with the inner and outer cases being spaced from each other and a clearance defined between the inner and outer cases.    
   
   
       3 . The exhaust gas purifying device according to  claim 1 , further comprising a fluid blocking member formed at an upstream end portion of the inner case for blocking communication between a space including an upstream end surface of the filter and the clearance.  
   
   
       4 . The exhaust gas purifying device according to  claim 1 , further comprising a support piece provided at an upstream side of the inner case.  
   
   
       5 . The exhaust gas purifying device according to  claim 3 , further comprising a fluid blocking member provided at a downstream side of the inner case and between the inner case and the outer case for blocking communication between a space including a downstream end surface of the filter and the clearance.  
   
   
       6 . The exhaust gas purifying device according to  claim 3 , wherein the fluid blocking member is a flange projecting from an outer peripheral surface of an end of the inner case, and the flange is secured to an outermost component of the outer case in an attachable or detachable manner.  
   
   
       7 . The exhaust gas purifying device according to  claim 1 , further comprising a heater for regenerating the filter disposed at an upstream position with respect to the filter, and a porous heat reflector arranged at a further upstream position with respect to the heater.  
   
   
       8 . A casing structure for an exhaust gas purifying device having a filter for use with an engine, the casing structure comprising: 
 a multiple case structure including an inner case supporting an outer peripheral surface of the filter for collecting, burning, and removing particulates contained in the exhaust gas discharged by the engine and at least one outer case arranged around the inner case, the casing structure including inner and outer cases spaced from each other with a clearance defined between the inner and outer cases.    
   
   
       9 . The exhaust gas purifying device according to  claim 1 , wherein the filter is a ceramic filter.  
   
   
       10 . The exhaust gas purifying device according to  claim 1 , wherein the filter is a sintered honeycomb body formed of porous silicon carbide.  
   
   
       11 . The exhaust gas purifying device according to  claim 1 , wherein the filter is an integral body formed by bundling a plurality of prism-shaped sintered honeycomb bodies formed of porous silicon carbide and binding the bundled bodies with an adhesive agent.  
   
   
       12 . A casing structure for an exhaust gas purifying device having a filter for use with an engine the casing structure comprising: 
 a multiple case structure including an inner case supporting an outer peripheral surface of the filter for collecting, burning, and removing particulates contained in the exhaust gas discharged by an engine, at least one outer case arranged around the inner case, and a heating means accommodating case accommodating a heating means for regenerating the filter arranged at an upstream side of the outer case, with the inner and outer cases spaced from each other and a clearance defined between the inner and outer cases.    
   
   
       13 . The exhaust gas purifying device according to  claim 2 , further comprising a fluid blocking member formed at an upstream end portion of the inner case for blocking communication between a space including an upstream end surface of the filter and the clearance.  
   
   
       14 . The exhaust gas purifying device according to  claim 2 , further comprising a support piece is provided at an upstream side of the inner case.  
   
   
       15 . The exhaust gas purifying device according to  claim 3 , further comprising a support piece is provided at an upstream side of the inner case.  
   
   
       16 . The exhaust gas purifying device according to  claim 3 , further comprising a fluid blocking member provided at a downstream side of the inner case and between the inner case and the outer case for blocking communication between a space including a downstream end surface of the filter and the clearance.  
   
   
       17 . The exhaust gas purifying device according to  claim 16 , wherein the fluid blocking member is a flange projecting from an outer peripheral surface of an end of the inner case, and the flange is secured to an outermost component of the outer case in an attachable or detachable manner.  
   
   
       18 . The exhaust gas purifying device according to  claim 5 , wherein the fluid blocking member is a flange projecting from an outer peripheral surface of an end of the inner case, and the flange is secured to an outermost component of the outer case in an attachable or detachable manner.  
   
   
       19 . The exhaust gas purifying device according to  claim 2 , further comprising a heater for regenerating the filter disposed at an upstream position with respect to the filter, and a porous heat reflector arranged at a further upstream position with respect to the heater.  
   
   
       20 . The exhaust gas purifying device according to  claim 3 , further comprising a heater for regenerating the filter disposed at an upstream position with respect to the filter, and a porous heat reflector arranged at a further upstream position with respect to the heater.