System for a heat energy recovery

Abstract

A system is provided for heat energy recovery in a vehicle including an internal combustion engine, such as a diesel engine, and a corresponding method is provided for operating such a system.

1 . An exhaust gas system for a vehicle, comprising:
 an arrangement for conveying an exhaust gas stream;   a thermodynamic engine comprising a heat exchanger positioned in the exhaust gas stream for recovery of heat from the exhaust gas stream, the thermodynamic engine comprising a working fluid circulation circuit holding a working fluid, the working fluid comprising a first base component mixed with a first additional component at a selected concentration, and   a first container for storing an amount of at least the first additional component of the working fluid, the first container fluidly connected to the working fluid circulation circuit,   wherein the first container is connected downstream of the heat exchanger at a gaseous phase of the working fluid circulation circuit, and that the exhaust gas system is further configured to allow adjustment of a pressure of the working fluid at the gaseous phase of the working fluid circulation circuit to conform with one of a plurality of predetermined conditions, wherein the plurality of predetermined conditions are dependent on different operational conditions for the vehicle.   
     
     
         2 . The exhaust gas system according to  claim 1 , further comprising a pressure detector arranged downstream of the heat exchanger at the gaseous phase of the working fluid circulation circuit, wherein the adjustment of the pressure of the working fluid at the gaseous phase of the working fluid circulation circuit is dependent on a pressure detected by the pressure detector. 
     
     
         3 . The exhaust gas system according to  claim 1 , wherein the pressure of the working fluid at the gaseous phase of the working fluid circulation circuit is adjusted by adjusting the selected concentration of the first additional component in relation to the first base component. 
     
     
         4 . The exhaust gas system according to  claim 1 , wherein the selected concentration of the first additional component in relation to the first base component is adjusted based on an ambient temperature detected by a temperature sensor. 
     
     
         5 . The exhaust gas system according to  claim 1 , further comprising a second container fluidly connected to the working fluid circulation circuit at the gaseous phase of the working fluid circulation circuit, wherein the first container is configured for allowing an increase of the pressure at one of the predetermined conditions, and the second container is configured for reducing the pressure at another one of the predetermined conditions. 
     
     
         6 . The exhaust gas system according to  claim 1 , further comprising a working fluid release means and an exhaust gas treatment unit, wherein the working fluid release means is configured to provide a fluid connection between the working fluid circulation circuit and the exhaust gas treatment unit, and the first container is configured for allowing an increase of the pressure at one of the predetermined conditions, and the exhaust gas treatment unit in combination with the working fluid release means is configured for reducing the pressure at another one of the predetermined conditions. 
     
     
         7 . The exhaust gas system according to  claim 6 , wherein in the exhaust gas treatment unit is formed by a selective catalytic reduction unit (SCR). 
     
     
         8 . The exhaust gas system according to  claim 6 , wherein the working fluid release means is connected downstream of the beat exchanger at the gaseous phase of the working fluid circulation circuit. 
     
     
         9 . The exhaust gas system according to  claim 1 , wherein the first additional component is at least one of ammonia and alcohol. 
     
     
         10 . The exhaust gas system according to  claim 5 , wherein at least one of the first and the second container is configured to stare liquid ammonia and/or an ammonia adsorbing material. 
     
     
         11 . The exhaust gas system according to  claim 2 , further comprising a control unit ( 110 ) being electrically connected to the pressure detector and configured to adjust, using at least one controllable valve ( 42 ) operatively connected to the control unit ( 110 ), the pressure of the working fluid at the gaseous phase of the working fluid circulation circuit. 
     
     
         12 . A method for controlling an exhaust gas system for a vehicle, the exhaust gas system comprising an arrangement for conveying an exhaust gas stream, a thermodynamic engine comprising a heat exchanger positioned in the exhaust gas stream for recovery of heat from the exhaust gas stream, the thermodynamic engine comprising a working fluid circulation circuit holding a working fluid, the working fluid comprising a first base component mixed with a first additional component at a concentration, and a first container for storing an amount of at least a first additional component of the working fluid, wherein the first container is fluidly connected downstream of the heat exchanger at a gaseous phase of the working fluid circulation circuit, comprising:
 detecting a pressure of the working fluid at a gaseous phase of the working fluid circulation circuit; and   adjusting the pressure to conform to one of a plurality of predetermined conditions, wherein the plurality of predetermined conditions are dependent on different operational conditions for the vehicle.   
     
     
         13 . The method according to  claim 12 , further comprising the step of:
 fluidly connecting a working fluid release means between the working fluid circulation circuit and an exhaust gas treatment unit provided with the vehicle, wherein the first container is configured for allowing an increase of the pressure at one of the predetermined conditions, and the exhaust gas treatment unit in combination with the working fluid release means is configured for reducing the pressure at another one of the predetermined conditions.   
     
     
         14 . The method according to  claim 12 , further comprising the steps of:
 determining a current operational condition for the vehicle, and   controlling a least one controllable valve dependent on the determined current operational condition for the vehicle for adjusting the pressure of the working fluid at the gaseous phase of the working fluid circulation circuit.   
     
     
         15 . Computer program product comprising a non-transitory computer readable medium having stored thereon a computer program for controlling an exhaust gas system for a vehicle according to  claim 12 .