A control system and a method for controlling the exhaust gas flow in an exhaust line of a combustion engine

Abstract

The present invention relates a control system and a method for controlling exhaust flow in an exhaust line of a combustion engine comprising at least one exhaust treatment component and an evaporator of a waste heat recovery system. The control system comprises a valve arrangement in the exhaust line control unit, a temperature sensor to sense a temperature of the exhaust treatment component and a control unit configured to position the valve arrangement in a first position, when the exhaust treatment component has a lower temperature than a specific temperature of exhaust gases directed flow through to the exhaust treatment component before being directed to flow through the evaporator, and in a second position, when the exhaust treatment component has a higher temperature than said specific temperature of exhaust gases that are directed to flow through the evaporator before being directed to flow through the exhaust treatment component.

1 . A control system for controlling exhaust flow in an exhaust line of a combustion engine, wherein the exhaust line comprises at least one exhaust treatment component and an evaporator of a waste heat recovery system, and wherein the control system comprises:
 a valve arrangement in the exhaust line;   a temperature sensor configured to sense a temperature related to a temperature of the exhaust treatment component; and   a control unit configured to position the valve arrangement in a first position, when the exhaust treatment component has a lower temperature than a specific temperature of exhaust gases that are directed to flow through the exhaust treatment component before being directed to flow through the evaporator, and to position the valve arrangement in a second position, when the exhaust treatment component has a higher temperature than a specific temperature of the exhaust gases that are directed to flow through the evaporator before being directed to flow through the exhaust treatment component,   wherein the valve arrangement comprises a valve member or a valve part configured to change flow direction of a working medium in the evaporator, such that the working medium and the exhaust gases always flow in opposite directions through the evaporator.   
     
     
         2 . A control system according to  claim 1 , wherein the valve arrangement comprises a valve member configured to alternatively direct the exhaust gases from an upstream exhaust line section to either the exhaust treatment component or to the evaporator. 
     
     
         3 . A control system according to  claim 1 , wherein the exhaust line comprises:
 at least one intermediate exhaust line configured to direct exhaust gases between the exhaust treatment component and the evaporator; and   a valve member configured to control exhaust gas flow through the intermediate exhaust line.   
     
     
         4 . A control system according to  claim 1 , wherein the valve arrangement comprises a valve member configured to alternatively direct exhaust gases from either the exhaust treatment component or the evaporator to a downstream exhaust line section. 
     
     
         5 . A control system according to  claim 1 , wherein the valve arrangement comprises a valve member which, in said first position, is configured to direct exhaust gases from an upstream exhaust line section to the exhaust treatment component and exhaust gases from the evaporator to a downstream exhaust line section. 
     
     
         6 . A control system according to  claim 5 , wherein said valve member is, in said second position, configured to direct exhaust gases from the upstream exhaust line section to the evaporator and exhaust gases from the exhaust treatment component to the downstream exhaust line section. 
     
     
         7 . A control system according to  claim 1 , wherein the valve arrangement comprises a valve member which, in said first position, is configured to direct exhaust gases from an upstream exhaust line section to the exhaust treatment component and exhaust gases from the exhaust treatment component to the evaporator. 
     
     
         8 . A control system according to  claim 7 , wherein said valve member is, in said second position, configured to direct exhaust gases from the evaporator to the exhaust treatment component and exhaust gases from the exhaust treatment component to a downstream exhaust line section. 
     
     
         9 . A control system according to  claim 1 , further comprising a temperature sensor configured to sense the temperature of the exhaust gases in an upstream exhaust line section. 
     
     
         10 . A control system according to  claim 1 , further comprising a sensor configured to sense a pressure or a the temperature of the working medium in the waste heat recovery system. 
     
     
         11 . A control system according to  claim 1 , wherein the exhaust treatment component is a selective catalytic reduction catalyst. 
     
     
         12 . A vehicle comprising a control system for controlling exhaust flow in an exhaust line of a combustion engine, wherein the exhaust line comprises at least one exhaust treatment component and an evaporator of a waste heat recovery system, and wherein the control system comprises:
 a valve arrangement in the exhaust line;   a temperature sensor configured to sense a temperature related to a temperature of the exhaust treatment component; and   a control unit configured to position the valve arrangement in a first position, when the exhaust treatment component has a lower temperature than a specific temperature of exhaust gases that are directed to flow through the exhaust treatment component before being directed to flow through the evaporator, and to position the valve arrangement in a second position, when the exhaust treatment component has a higher temperature than a specific temperature of the exhaust gases that are directed to flow through the evaporator before being directed to flow through the exhaust treatment component,   wherein the valve arrangement comprises a valve member or a valve part configured to change flow direction of a working medium in the evaporator, such that the working medium and the exhaust gases always flow in opposite directions through the evaporator.   
     
     
         13 . A method for controlling the exhaust flow in an exhaust line of a combustion engine in a vehicle, wherein the exhaust line comprises at least one exhaust treatment component and an evaporator of a waste heat recovery, a valve arrangement, wherein said method comprises:
 directing exhaust gases in the exhaust line to flow through the exhaust treatment component before being directed to flow through the evaporator, when the exhaust treatment component has a lower temperature than a specific temperature;   directing the exhaust gases to flow through the evaporator before being directed to flow through the exhaust treatment component, when the exhaust treatment component has a higher temperature than said specific temperature; and   changing flow direction of a the working medium in the evaporator, such that the working medium and the exhaust gases always flow in opposite directions through the evaporator.   
     
     
         14 . A vehicle according to  claim 12 , wherein the valve arrangement comprises a valve member configured to alternatively direct the exhaust gases from an upstream exhaust line section to either the exhaust treatment component or to the evaporator. 
     
     
         15 . A vehicle according to  claim 12 , wherein the exhaust line comprises:
 at least one intermediate exhaust line configured to direct exhaust gases between the exhaust treatment component and the evaporator; and   a valve member configured to control exhaust gas flow through the intermediate exhaust line.   
     
     
         16 . A vehicle according to  claim 12 , wherein the valve arrangement comprises a valve member configured to alternatively direct exhaust gases from either the exhaust treatment component or the evaporator to a downstream exhaust line section. 
     
     
         17 . A method according to  claim 13  further comprising alternatively directing the exhaust gases from an upstream exhaust line section to either the exhaust treatment component or to the evaporator. 
     
     
         18 . A method according to  claim 13  further comprising alternatively directing exhaust gases from either the exhaust treatment component or the evaporator to a downstream exhaust line section.