Warm-up method and system for warming up exhaust purification catalyst

Abstract

A warm-up system for warming up an exhaust purification catalyst arranged in an exhaust passage of an engine equipped with a turbocharger. The warm-up system includes an electric motor coupled to a turbine of the turbocharger, and control device that operates the electric motor to apply counter torque to the turbine when the exhaust purification catalyst needs to be warmed up.

1 . A warm-up method for warming up an exhaust purification catalyst arranged in an exhaust passage of an internal combustion engine equipped with a turbocharger,
 wherein temperature of an exhaust gas in the exhaust passage is raised by applying counter torque to a turbine of the turbocharger.   
     
     
         2 . The warm-up method according to  claim 1 , wherein the exhaust gas is recirculated from an upstream side of the turbine back to a downstream side of a compressor of the turbocharger. 
     
     
         3 . The warm-up method according to  claim 1 , wherein the turbocharger includes a turbine flow rate adjusting device that adjusts a flow rate of the exhaust gas flowing in to the turbine, and the turbine flow rate adjusting device is controlled such that energy loss of the exhaust gas is lessened. 
     
     
         4 . The warm-up method according to  claim 1 , wherein the turbocharger includes a turbine flow rate adjusting device that adjusts a flow rate of the exhaust gas flowing into the turbine, and the turbine flow rate adjusting device is controlled such that the exhaust gas is recirculated from an upstream side of the turbine back to a downstream side of a compressor of the turbocharger. 
     
     
         5 . A warm-up system for warming up an exhaust purification catalyst arranged in an exhaust passage of an internal combustion engine equipped with a turbocharger, comprising:
 a load device coupled to a turbine of the turbocharger;   and   a control device that operates the load device to apply counter torque to the turbine when the exhaust purification catalyst needs to be warmed up.   
     
     
         6 . The warm-up system according to  claim 5 , wherein the control device controls the load device in accordance with an output of a sensor for detecting a rotating speed of the turbine or a pressure in the exhaust passage. 
     
     
         7 . The warm-up system according to  claim 5 ,
 further comprising:   an exhaust gas recirculation device for recirculating an exhaust gas of the engine from an upstream side of the turbine back to a downstream side of a compressor of the turbocharger; and   a control device that operates the exhaust gas recirculation device to recirculate the exhaust gas when the exhaust purification catalyst needs to be warmed up.   
     
     
         8 . The warm-up system according to  claim 5 ,
 further comprising:   a turbine flow rate adjusting device that adjusts a flow rate of an exhaust gas flowing into the turbine; and   a control device that operates the turbine flow rate adjusting device to lessen energy loss of the exhaust gas when the exhaust purification catalyst needs to be warmed up.   
     
     
         9 . The warm-up system according to  claim 5 ,
 further comprising:   an exhaust gas recirculation device for recirculating an exhaust gas of the engine from an upstream side of the turbine back to a downstream side of a compressor of the turbocharger;   a turbine flow rate adjusting device that adjusts a flow rate of the exhaust gas flowing into the turbine; and   a control device that operates the exhaust gas recirculation device and the turbine flow rate adjusting device to recirculate the exhaust gas when the exhaust purification catalyst needs to be warmed up.