System and method for increasing the temperature of gases within an exhaust of an internal combustion engine

Abstract

Reformate gas is supplied into the exhaust 4 of an internal combustion engine 2 at a location upstream of an oxidation catalyst 6 and an ignition source 14 is provided either upstream or downstream of the oxidation catalyst and upstream of further exhaust gas treatment devices 8 for igniting the mixture in the exhaust to provide rapid heat up of the oxidation catalyst 6 and further exhaust gas treatment devices 8 . In a further embodiment reformate gas is injected into the exhaust 24 upstream of a turbocharger 26 to increase turbocharger boost pressure at low engine speeds.

1 . A method of increasing the temperature of exhaust gases within the exhaust of an internal combustion engine comprising supplying a combustible gas into the exhaust at a location downstream of a combustion chamber of the internal combustion engine.  
   
   
       2 . A method as claimed in  claim 1 , comprising the further steps of providing an ignition source within the exhaust for igniting said combustible gas and operating said ignition source to ignite said combustible gas in said exhaust.  
   
   
       3 . A method as claimed in  claim 1 , wherein the combustible gas comprises reformate gas.  
   
   
       4 . A method as claimed in  claim 2 , wherein the combustible gas comprises reformate gas.  
   
   
       5 . A system for increasing the temperature of exhaust gas within an exhaust ( 4 ,  24 ) of an internal combustion engine ( 2 ,  22 ), said system comprising a source ( 10 ,  34 ) of combustible gas and means for injecting said combustible gas into the exhaust ( 4 ,  24 ) at a location downstream of a combustion chamber of the internal combustion engine.  
   
   
       6 . A system as claimed in  claim 5 , further comprising an ignition source ( 14 ) for igniting the combustible gas within the exhaust ( 4 ).  
   
   
       7 . A system as claimed in  claim 5 , wherein the combustible gas comprises reformate gas.  
   
   
       8 . A system as claimed in  claim 6 , wherein the combustible gas comprises reformate gas.  
   
   
       9 . A system as claimed in  claim 6  when dependent upon  claim 5 , wherein said combustible gas is supplied into the exhaust ( 4 ) at a location ( 12 ) upstream of a first exhaust gas treatment device ( 6 ) provided in the exhaust ( 4 ) whilst said ignition source ( 14 ) is provided at a location either upstream or downstream of said first exhaust gas treatment device ( 6 ).  
   
   
       10 . A system as claimed in  claim 7  when dependent upon  claim 5 , wherein said combustible gas is supplied into the exhaust ( 4 ) at a location ( 12 ) upstream of a first exhaust gas treatment device ( 6 ) provided in the exhaust ( 4 ) whilst said ignition source ( 14 ) is provided at a location either upstream or downstream of said first exhaust gas treatment device ( 6 ).  
   
   
       11 . A system as claimed in  claim 9 , wherein said first exhaust gas treatment device ( 6 ) comprises an oxidation catalyst.  
   
   
       12 . A system as claimed in  claim 9 , wherein further exhaust gas treatment devices ( 8 ), such as a particulate filter and a NOx trap, are provided in the exhaust ( 4 ) downstream of said ignition source ( 14 ).  
   
   
       13 . A system as claimed in  claim 11 , wherein further exhaust gas treatment devices ( 8 ), such as a particulate filter and a NOx trap, are provided in the exhaust ( 4 ) downstream of said ignition source ( 14 ).  
   
   
       14 . A system as claimed in  claim 5 , wherein a turbocharger ( 26 ) is provided in the exhaust ( 24 ) and the combustible gas is supplied into the exhaust ( 24 ) at a location ( 36 ) upstream of the turbocharger ( 26 ).  
   
   
       15 . A system as claimed in  claim 6 , wherein a turbocharger ( 26 ) is provided in the exhaust ( 24 ) and the ignition source is located upstream of the turbocharger ( 26 ).  
   
   
       16 . A system as claimed in  claim 15 , wherein the ignition source is a spark plug.  
   
   
       17 . A system as claimed in  claim 7 , wherein a turbocharger ( 26 ) is provided in the exhaust ( 24 ) and the combustible gas is supplied into the exhaust ( 24 ) at a location ( 36 ) upstream of the turbocharger ( 26 ).