Internal combustion engine

Abstract

An internal combustion engine according to the present invention includes an exhaust treatment apparatus provided in an exhaust passage, and a burner apparatus provided upstream of the exhaust treatment apparatus to raise exhaust temperature. A valve driving state of at least one of an intake valve and an exhaust valve is controlled so as to reduce a flow rate of exhaust gas passing through the burner apparatus when the flow rate of the exhaust gas is equal to or larger than a predetermined value. Possible flame blow-out in the burner apparatus can be prevented or suppressed to ensure sufficient ignition performance.

1 . An internal combustion engine comprising:
 an exhaust treatment apparatus provided in an exhaust passage;   a burner apparatus provided upstream of the exhaust treatment apparatus to raise exhaust temperature, and   valve driving control unit for controlling a valve driving state of at least one of an intake valve and an exhaust valve so as to reduce a flow rate of exhaust gas passing through the burner apparatus when the flow rate of the exhaust gas is equal to or larger than a predetermined value.   
     
     
         2 . The internal combustion engine according to  claim 1 , wherein the valve driving control unit comprises:
 a valve timing varying mechanism adapted to vary a valve timing for the exhaust valve, and   first control unit programmed to control the valve timing varying mechanism in such a manner that the exhaust valve is kept open until during a descent of a piston after end of an exhaust stroke, when the flow rate of the exhaust gas is equal to or larger than the predetermined value.   
     
     
         3 . The internal combustion engine according to  claim 1 , wherein the valve driving control unit comprises:
 a halting mechanism adapted to halt operation of at least one of the intake valve and the exhaust valve in a part of a plurality of cylinders; and   second control unit programmed to control the halting mechanism so as to halt the operation of at least one of the intake valve and the exhaust valve in the part of cylinders, when the flow rate of the exhaust gas is equal to or larger than the predetermined value.   
     
     
         4 . The internal combustion engine according to  claim 1 , further comprising detection unit for detecting an amount of intake air as a substitute value for the flow rate of the exhaust gas, and
 wherein the valve driving control unit controls the valve driving state of at least one of the intake valve and the exhaust valve so as to reduce the flow rate of the exhaust gas when the amount of intake air detected by the detection unit is equal to or larger than a predetermined value.   
     
     
         5 . The internal combustion engine according to  claim 1 , wherein the burner apparatus comprises a fuel addition valve, ignition unit, and a pretreatment catalytic converter.