Method pertaining to an scr system and an scr system

Abstract

For an SCR system for a motor vehicle ( 100; 110 ), the vehicle including a feed device ( 230 ) to feed reducing agent from a container ( 205 ) to a dosing unit ( 250 ) for supply of reducing agent to an exhaust duct of the vehicle ( 100; 110 ); a method of controlling the dosage of the dosing unit ( 250 ) by a pressure (Pr) at which reducing agent is dosed, and/or controlling pressure (Pr) of a rotation speed (RPM) of the feed device ( 230 ). Also a computer program product with program code (P) for a computer ( 200; 210 ) for implementing the method. Also an SCR system and a motor vehicle ( 100, 110 ) equipped with the SCR system.

1 . A method pertaining to an SCR system for a motor vehicle comprising
 an engine having an exhaust duct;   a feed device configured to feed a reducing agent from a container to a dosing unit for supply of the reducing agent to the exhaust duct of the vehicle, the feed device being rotatable in a path of the reducing agent to the dosing unit, the rotation being at a controllable rotation speed;   the method comprising,   controlling a dosage of the reducing agent supplied by the dosing unit by controlling a pressure (Pr) at which the reducing agent is dosed, and controlling the pressure (Pr) by control of the rotation speed of the feed device.   
     
     
         2 . A method according to  claim 1 , in which the system further comprises a feedback line for reducing agent from the dosing unit to the container and an alterable constriction in the feedback line;
 the method further comprising controlling the pressure (Pr) by altering the constriction in the feedback line.   
     
     
         3 . A method according to  claim 1 , further comprising controlling the pressure (Pr) by altering the configuration of the dosing unit. 
     
     
         4 . A method according to  claim 1 , further comprising controlling the dosage of the dosing unit by means of the pressure (Pr) based on a prevailing temperature (T2) of a surface or a component of the exhaust duct ( 290 ). 
     
     
         5 . A method according to  claim 1 , further comprising controlling the dosage of the dosing unit by means of the pressure (Pr) based on a prevailing temperature (T1) of an exhaust flow from the engine and/or a prevailing mass flow (MF) of exhaust gases from the engine. 
     
     
         6 . A method according to  claim 1 , further comprising controlling the dosage of the dosing unit by means of the pressure (Pr) and a dosing cycle rate (CF). 
     
     
         7 . A method according to  claim 1 , further comprising the varying the pressure (Pr) of the reducing agent is within a range of 5-15 bar. 
     
     
         8 . A method according to  claim 1 , further comprising controlling the dosage of the dosing unit by means of the pressure (Pr) and a dosing cycle rate (CF) on the basis of a prevailing exhaust temperature (T) and/or a prevailing mass flow (MF) of exhaust gases from the engine of the vehicle. 
     
     
         9 . An SCR system for a motor vehicle comprising:
 a feed device configured to feed reducing agent from a container to a dosing unit for supply of the reducing agent to an exhaust duct of the vehicle;   the feed device being rotatable in a path of the reducing agent to the dosing unit, the rotation being at a controllable rotation speed;   a control device for controlling a dosage of the dosing unit by means of a pressure (Pr) at which the reducing agent is dosed, and   
       and the control device being configured for controlling the pressure by control of a rotation speed (RPM) of the feed device. 
     
     
         10 . An SCR system according to  claim 9 , further comprising:
 a feedback line for reducing agent from the dosing unit to the container and an alterable constriction in the feedback line;   the control device being configured for controlling the pressure (Pr) by altering the constriction in a feedback line for the reducing agent from the dosing unit to the container.   
     
     
         11 . An SCR system according to  claim 9 , further comprising the control device being configured for controlling the pressure (Pr) by altering the configuration of the dosing unit. 
     
     
         12 . An SCR system according to  claim 9 , further comprising the control device being configured for controlling the dosage of the dosing unit by means of the pressure (Pr) based on a prevailing temperature (T2) of a surface or a component of the exhaust duct. 
     
     
         13 . An SCR system according to  claim 12 , further comprising a sensor for determining a prevailing temperature (T2) of a surface or component of the exhaust duct. 
     
     
         14 . An SCR system according to  claim 9 , further comprising the control device being configured for controlling the dosage of the dosing unit by means of the pressure (Pr) based on a prevailing temperature (T1) of an exhaust flow from the engine and/or a prevailing mass flow (MF) of exhaust gases from the engine. 
     
     
         15 . An SCR system according to  claim 9 , further comprising the control device being configured for controlling the dosage of the dosing unit by means of the pressure (Pr) and a dosing cycle rate (CF). 
     
     
         16 . An SCR system according to  claim 9 , further comprising the control device being configured for varying the pressure (Pr) of the reductant within a range of 5-15 bar. 
     
     
         17 . An SCR system according to  claim 9 , further comprising the control device being configured for controlling the dosage of the dosing unit by means of the pressure (Pr) and a dosing cycle rate (CF) on the basis of a prevailing exhaust temperature (T) and/or a prevailing mass flow (MF) of exhaust gases from the engine of the vehicle. 
     
     
         18 . A motor vehicle provided with an SCR system according to  claim 9 . 
     
     
         19 . A motor vehicle according to  claim 18 , comprising any from among a truck, bus or car. 
     
     
         20 . (canceled) 
     
     
         21 . A computer program product pertaining to an SCR system, the system comprising a feed device to feed reducing agent from a container to a dosing unit for supply of the reducing agent to an exhaust duct of a vehicle;
 the program product comprising a program code stored on a non-volatile computer-readable medium wherein the program comprises program code for causing an electronic control unit or another computer connected to the electronic control unit to perform steps according to  claim 1  for when the computer program is run on the electronic control unit or another computer connected to the electronic control unit.