Method for automatically controlling a vapor content of a working medium heated in a vaporizer of a system for carrying out a thermodynamic cycle, control unit for a system, system for a thermodynamic cycle, and arrangement consisting of an internal combustion engine and a system

Abstract

A method for automatically controlling a steam content of a working medium heated in an evaporator of a system for carrying out a thermodynamic cycle with the following steps: carrying out a phase separation for the working medium downstream from the evaporator, wherein liquid components are separated from vapor components of the working medium; conducting the separated liquid components to a reservoir; determining a level in the reservoir; and varying a control variable for automatically controlling the steam content as a function of the level.

We claim: 
     
         1 . A method for automatically controlling a steam content of a working medium heated in an evaporator of a system for carrying out a thermodynamic cycle, comprising the steps of:
 carrying out a phase separation for the working medium downstream from the evaporator, wherein liquid components are separated from vapor components of the working medium;   conducting the separated liquid components to a reservoir;   determining a level in the reservoir; and   varying a command variable to control the steam content automatically as a function of the level.   
     
     
         2 . The method according to  claim 1 , including varying a mass flow of the working medium in the system as a function of the level. 
     
     
         3 . The method according to  claim 2 , including determining a change in the level in the reservoir, and varying the mass flow is varied as a function of the change in level. 
     
     
         4 . The method according to  claim 2 , wherein the mass flow is varied by variation of an output of a conveying device, wherein the conveying device is used to convey the working medium in the system. 
     
     
         5 . The method according to  claim 1 , wherein a pressure and/or a temperature of the working medium downstream from the evaporator and/or upstream from a separation device and/or upstream of an expansion device of the system is determined and used as input for the automatic control of the steam content. 
     
     
         6 . The method according to  claim 1 , wherein the automatic steam content control is calibrated by operating the system on or beyond a saturated steam curve of the working medium and by intentional deviation from the saturated steam curve into a wet steam region. 
     
     
         7 . The method according to  claim 1 , wherein a withdrawal of liquid from the reservoir is used as an input for the automatic steam content control. 
     
     
         8 . A control unit for a system for a thermodynamic cycle, wherein the control unit is set up to carry out a method for automatically controlling a steam content of a working medium heated in a evaporator of the system according to  claim 1 , wherein the control unit is operatively configured to determine a level in a reservoir, which is located downstream from the evaporator and is connected to a separation device, and to vary a command variable for automatically controlling the steam content as a function of the level. 
     
     
         9 . A system for a thermodynamic cycle, comprising a control unit according to  claim 8 . 
     
     
         10 . The system according to  claim 9 , wherein the system comprises a evaporator, a separation device, an expansion device, a condenser, and a conveying device for the working medium, arranged in series in a flow direction of the working medium through a circuit, wherein a reservoir, to which liquid components of the working medium separated in the separation device are conducted, is connected to the separation device. 
     
     
         11 . The system according to  claim 9 , wherein the expansion device is configured as a helical screw expander. 
     
     
         12 . The system according to  claim 9 , wherein the system is arranged to use waste heat of an internal combustion engine. 
     
     
         13 . An arrangement, comprising: an internal combustion engine; and a system for a thermodynamic cycle according to  claim 9 .