Control unit and control method for reductant supply system

Abstract

There are provided a control unit and a control method for a reductant supply system, which are capable of reducing energy consumption by immediately stopping heating means in the case of entering an idling stop mode. A control unit which performs control of a reductant supply system includes an idling stop determination portion that determines whether an internal combustion engine is stopped by idling stop control that automatically stops the internal combustion engine, a heating means operation determination portion that determines whether the heating means provided in the reductant supply route that supplies the liquid reductant to the reductant injection valve is in operation, and a heating means control portion that stops operation of the heating means in a state where the internal combustion engine is automatically stopped and the heating means is in operation.

1 - 9 . (canceled) 
     
     
         10 . A control unit for a reductant supply system, which performs control of a reductant supply system which is used in an exhaust gas purification device that injects and supplies a liquid reductant to an exhaust gas upstream side of a reduction catalyst disposed in an exhaust gas passage of an internal combustion engine, and that reduces and purifies nitrogen oxides contained in exhaust gas using the reduction catalyst, the reductant supply system having a storage tank that stores the liquid reductant, a pump that pressure-feeds the liquid reductant stored in the storage tank, a reductant injection valve that controls a supply amount of the liquid reductant that is pressure-fed by the pump, and a reductant supply passage through which the liquid reductant is caused to flow, the control unit comprising:
 an idling stop determination portion that determines whether the internal combustion engine is stopped by idling stop control that automatically stops the internal combustion engine;   a heating means operation determination portion that determines whether heating means provided in a reductant supply route that supplies the liquid reductant to the reductant injection valve is in operation; and   a heating means control portion that stops operation of the heating means in a state where the internal combustion engine is automatically stopped and the heating means is in operation.   
     
     
         11 . The control unit for a reductant supply system according to  claim 10 , wherein the heating means control portion stops the operation of the heating means when a predetermined period of time elapses after it is determined that the internal combustion engine has been automatically stopped. 
     
     
         12 . The control unit for a reductant supply system according to  claim 10 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         13 . The control unit for a reductant supply system according to  claim 11 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         14 . The control unit for a reductant supply system according to  claim 10 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         15 . The control unit for a reductant supply system according to  claim 11 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         16 . The control unit for a reductant supply system according to  claim 12 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         17 . The control unit for a reductant supply system according to  claim 13 , further comprising an outside air temperature detection portion that detects outside air temperature information, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the outside air temperature. 
     
     
         18 . The control unit for a reductant supply system according to  claim 10 , further comprising an energy detection portion that detects a magnitude of energy supplied from a source of power of the heating means, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the magnitude of the energy. 
     
     
         19 . The control unit for a reductant supply system according to  claim 11 , further comprising an energy detection portion that detects a magnitude of energy supplied from a source of power of the heating means, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the magnitude of the energy. 
     
     
         20 . The control unit for a reductant supply system according to  claim 12 , further comprising an energy detection portion that detects a magnitude of energy supplied from a source of power of the heating means, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the magnitude of the energy. 
     
     
         21 . The control unit for a reductant supply system according to  claim 14 , further comprising an energy detection portion that detects a magnitude of energy supplied from a source of power of the heating means, wherein the heating means control portion changes a time period from when it is determined that the internal combustion engine is automatically stopped until when the heating means is stopped, in accordance with the magnitude of the energy. 
     
     
         22 . The control unit for a reductant supply system according to  claim 10 , further comprising a reductant return control portion that causes the liquid reductant of the reductant supply route to be collected into the storage tank when the internal combustion engine is automatically stopped. 
     
     
         23 . The control unit for a reductant supply system according to  claim 11 , further comprising a reductant return control portion that causes the liquid reductant of the reductant supply route to be collected into the storage tank when the internal combustion engine is automatically stopped. 
     
     
         24 . The control unit for a reductant supply system according to  claim 21 , further comprising a reductant return control portion that causes the liquid reductant of the reductant supply route to be collected into the storage tank when the internal combustion engine is automatically stopped. 
     
     
         25 . The control unit for a reductant supply system according to  claim 22 , wherein the reductant return control portion collects the liquid reductant when a predetermined period of time elapses after it is determined that the internal combustion engine has been automatically stopped. 
     
     
         26 . The control unit for a reductant supply system according to claim  5 , wherein the reductant return control portion collects the liquid reductant when a predetermined period of time elapses after it is determined that the internal combustion engine has been automatically stopped. 
     
     
         27 . The control unit for a reductant supply system according to  claim 10 , wherein the idling stop determination portion determines that the internal combustion engine has been automatically stopped when at least a key switch of the internal combustion engine is on and when a rotational speed of the internal combustion engine continues to be equal to or less than a predetermined value for a predetermined period of time. 
     
     
         28 . The control unit for a reductant supply system according to  claim 10 , wherein the idling stop determination portion determines whether the internal combustion engine has been automatically stopped, based on a signal from an engine control unit that performs operation control of the internal combustion engine. 
     
     
         29 . A control method for a reductant supply system which is used in an exhaust gas purification device that injects and supplies a liquid reductant to an exhaust gas upstream side of a reduction catalyst disposed in an exhaust gas passage of an internal combustion engine, and that reduces and purifies nitrogen oxides contained in exhaust gas using the reduction catalyst, the reductant supply system having a storage tank that stores the liquid reductant, a pump that pressure-feeds the liquid reductant stored in the storage tank, a reductant injection valve that controls a supply amount of the liquid reductant that is pressure-fed by the pump, and a reductant supply passage through which the liquid reductant flows, the control method comprising the steps of: determining whether heating means provided in a reductant supply route is in operation in a state where the internal combustion engine is stopped by idling stop control that automatically stops the internal combustion engine; and stopping operation of the heating means when the heating means is in operation.