Internal combustion engine

Abstract

An internal combustion engine according to the present invention includes an exhaust treatment device provided in an exhaust passage and a burner device provided upstream of the exhaust treatment device to raise exhaust temperature. The burner device includes a fuel addition valve configured to add fuel into the exhaust passage, a first ignition device configured to ignite the added fuel, a burner catalyst provided downstream of the first ignition device, and a second ignition device provided downstream of the burner catalyst. The burner catalyst partitions the exhaust passage into an infra-catalyst passage formed inside the burner catalyst and an extra-catalyst passage formed outside the burner catalyst. The second ignition means is positioned between the extra-catalyst passage and the exhaust treatment device. Generated soot can be combusted by the second ignition device.

1 . An Interned combustion engine comprising an exhaust treatment device provided in an exhaust passage and a burner device provided upstream of the exhaust treatment device to raise exhaust temperature, the internal combustion engine being characterized in that:
 the burner device includes a fuel addition valve configured to add fuel into the exhaust passage, first ignition means for igniting the fuel added through the fuel addition valve, a burner catalyst provided downstream of the first ignition means, and second ignition means provided downstream of the burner catalyst,   the burner catalyst is formed to occupy a part of a cross section of the exhaust passage, thus partitioning the exhaust passage into an intra-catalyst passage formed inside the burner catalyst and an extra-catalyst passage formed outside the burner catalyst, and   the second ignition means is positioned between the extra-catalyst passage and the exhaust treatment device in an axial direction of the exhaust passage.   
     
     
         2 . The internal combustion engine according to  claim 1 , characterized in that the second ignition means is positioned near an outlet, of the extra-catalyst passage. 
     
     
         3 . The internal combustion engine according to  claim 1  or  2 , characterized in that the second ignition means is positioned inside an extended area obtained by extending the extra-catalyst passage downstream along the axial direction of the exhaust passage. 
     
     
         4 . The internal combustion engine according to any one of  claims 1  to  3 , characterized in that the burner catalyst is formed to contact an inner circumferential surface of the exhaust passage and includes at least one through-hole penetrating the burner catalyst in the axial direction of the exhaust passage, and the through-hole forms the extra-catalyst passage. 
     
     
         5 . The internal combustion engine according to  claim 4 , characterized in that the at least one through-hole is formed in a central portion of the burner catalyst, and the burner device is thus annularly formed. 
     
     
         6 . The internal, combustion engine according to  claim 4 , characterized in that a plurality of the through-holes are formed at respective predetermined positions of the burner catalyst. 
     
     
         7 . The internal combustion engine according to any one of  claims 1  to  3 , characterized in that the burner catalyst is positioned at a distance from the inner circumferential surface of the exhaust passage, and the annular extra-catalyst passage is formed radially outside the burner catalyst. 
     
     
         8 . The internal combustion engine according to any one of  claims 1  to  7 , characterized by comprising:
 acquisition means for acquiring a temperature of the exhaust processing device; and 
 control means for controlling the fuel addition valve, the first ignition moans, and the second ignition means based on the temperature acquired by the acquisition means, and 
 in that the control means activates the fuel addition valve, the first ignition means, and the second ignition means when the acquired temperature is within a predetermined first temperature range, and activates the fuel addition valve and the second ignition means while inactivating the first ignition means when the acquired temperature is within a predetermined second temperature range higher than the first temperature ranges. 
 
     
     
         9 . The internal combustion engine according to any one of  claims 1  to  8 , characterized in that the exhaust treatment device comprises an oxidation catalyst.