Vehicle with system for recovering waste heat

Abstract

A vehicle comprising: an internal combustion engine comprising a combustion chamber and an exhaust duct; and a system for recovering waste heat of the internal combustion engine, wherein the waste heat recovery system comprises: i) a first heat exchanger configured to evaporate a working fluid by transferring heat from a heated medium originating from the engine; ii) an expander unit configured to expand the working fluid that has been evaporated in the first heat exchanger and produce a power output; iii) a second heat exchanger configured to condense the working fluid; and iv) at least one pump for feeding the condensed working fluid to the first heat exchanger. The invention is characterized in that the waste heat recovery system is configured to use water as working fluid.

1 . A vehicle, comprising
 an internal combustion engine comprising a combustion chamber and an exhaust duct; and   a system for recovering waste heat of the internal combustion engine, wherein the waste heat recovery system comprises:
 i) a first heat exchanger configured to evaporate a working fluid by transferring heat from a heated medium originating from the engine; 
 ii) an expander unit configured to expand the working fluid that has been evaporated in the first heat exchanger and produce a power output; 
 iii) a second heat exchanger configured to condense the working fluid; and 
 iv) at least one pump for feeding the condensed working fluid to the first heat exchanger; 
 wherein the waste heat recovery system is configured to use water as working fluid; 
 wherein a working fluid/water passage is arranged between the expander unit and the exhaust duct so as to direct the expanded working fluid/water into the exhaust duct; 
 wherein the second heat exchanger is arranged in association with the exhaust duct and being configured to condense water present in the exhaust gas; and 
 wherein the second heat exchanger is positioned at or downstream a point or zone of the exhaust duct at which the expanded working fluid/water is directed into the exhaust gas. 
   
     
     
         2 . The vehicle according to  claim 1 , wherein the vehicle further comprises:
 a system for introducing water directly or indirectly into the combustion chamber of the internal combustion engine, wherein the vehicle comprises a water distribution system configured to distribute the water condensed in the second heat exchanger between the first heat exchanger and the combustion chamber.   
     
     
         3 . The vehicle according to  claim 1 , wherein the at least one pump for feeding the condensed working fluid to the first heat exchanger includes a high pressure pump. 
     
     
         4 . The vehicle according to  claim 3 , wherein the high pressure pump is capable of providing the working fluid/water with a pressure of at least 20 bar. 
     
     
         5 . The vehicle according to  claim 1 , wherein the vehicle comprises a water tank arranged for storage of water condensed in the second heat exchanger. 
     
     
         6 . The vehicle according to  claim 1 , wherein the expander unit comprises a steam expander and a power output that is connected to an electric generator for production of electricity or that is mechanically connected to a drivetrain of the internal combustion engine. 
     
     
         7 . The vehicle according to  claim 2 , wherein the water distribution system comprises water conduits leading from the second heat exchanger to the first heat exchanger and to the engine. 
     
     
         8 . The vehicle according to  claim 2 , wherein the water tank forms a common water tank for both the waste heat recovery system and the system for introducing water directly or indirectly into the combustion chamber. 
     
     
         9 . The vehicle according to  claim 8 , wherein the vehicle comprises a condensate pump configured to pump water from the second heat exchanger to the water tank. 
     
     
         10 . The vehicle according to  claim 9 , wherein the water distribution system comprises a low pressure pump arranged upstream of the water tank, wherein the low pressure pump is configured to pump water towards both the first heat exchanger and the engine. 
     
     
         11 . The vehicle according to  claim 1 , wherein the heated medium originating from the engine is exhaust gas. 
     
     
         12 . The vehicle according to  claim 1 , wherein the internal combustion engine is arranged for propulsion of the vehicle. 
     
     
         13 . A system for recovering waste heat of an internal combustion engine comprising a combustion chamber and an exhaust duct, the waste heat recovery system comprising:
 i) a first heat exchanger configured to evaporate a working fluid by transferring heat from a heated medium originating from the engine;   ii) an expander unit configured to expand the working fluid that has been evaporated in the first heat exchanger and produce a power output;   iii) a second heat exchanger configured to condense the working fluid; and   iv) at least one pump for feeding the condensed working fluid to the first heat exchanger;   wherein the waste heat recovery system is configured to use water as working fluid;   wherein a working fluid/water passage is arranged between the expander unit and the exhaust duct so as to direct the expanded working fluid/water into the exhaust duct;   wherein the second heat exchanger is arranged in association with the exhaust duct and being configured to condense water present in the exhaust gas; and   wherein the second heat exchanger is positioned at or downstream a point or zone of the exhaust duct at which the expanded working fluid/water is directed into the exhaust gas.