Rankine cycle system

Abstract

A Rankine cycle system mounted on a vehicle has a Rankine cycle circuit through which working fluid circulates, a power generator, a power storage and a controller. The Rankine cycle circuit includes a fluid expansion device, a fluid transferring device, first and second passages, a heater, a cooling device, a bypass passage and a flow regulating valve. The bypass passage connects the first passage to the second passage. The flow regulating valve is provided in the bypass passage for opening and closing the bypass passage. The power generator converts the work generated by the fluid expansion device into electric power. The controller monitors charge rate of the electric power charged in the power storage and controls an operation of the flow regulating valve based on the monitored charge rate. The controller causes the flow regulating valve to be opened when the monitored charge rate is greater than a predetermined value.

1 . A Rankine cycle system mounted on a vehicle comprising:
 a Rankine cycle circuit through which working fluid circulates, the Rankine cycle circuit including;
 a fluid expansion device expanding the working fluid for generating work; 
 a fluid transferring device transferring the working fluid to the fluid expansion device; 
 a first passage connecting the fluid transferring device to the fluid expansion device; 
 a second passage connecting the fluid expansion device to the fluid transferring device; 
 a heater provided in the first passage for heating the working fluid; 
 a cooling device provided in the second passage for cooling the working fluid; 
 a bypass passage connecting the first passage to the second passage, and 
 a flow regulating valve provided in the bypass passage for opening and closing the bypass passage; 
   a power generator converting the work generated by the fluid expansion device into electric power;   a power storage storing the electric power converted by the power generator, and   a controller monitoring charge rate of the electric power charged in the power storage, the controller controlling an operation of the flow regulating valve based on the charge rate, the controller causing the flow regulating valve to be opened when the charge rate reaches or is greater than a first predetermined value.   
     
     
         2 . The Rankine cycle system according to  claim 1 , wherein the controller monitors an electric load of the vehicle and controls an opening of the flow regulating valve based on the monitored electric load of the vehicle in opening the flow regulating valve, thereby adjusting a flow rate of the working fluid flowing through the bypass passage and the controller controls generation of the electric power by the power generator in such a way to suppress an increase of the charge rate of the power storage. 
     
     
         3 . The Rankine cycle system according to  claim 1 , wherein the controller controls an opening of the flow regulating valve based on a minimum electric load required for operating the vehicle under normal conditions in opening the flow regulating valve, thereby adjusting the flow rate of the working fluid flowing through the bypass passage and the controller controls generation of the electric power by the power generator in such a way to suppress an increase of the charge rate of the power storage. 
     
     
         4 . The Rankine cycle system according to  claim 1 , wherein the controller monitors an electric load of the vehicle and controls an opening of the flow regulating valve such that the amount of the electric power supplied to the power storage is less than the monitored electric load of the vehicle and more than a minimum electric load required for operating the vehicle under normal conditions, thereby adjusting the flow rate of the working fluid flowing through the bypass passage and the controller controls generation of the electric power by the power generator in such a way to suppress an increase of the charge rate of the power storage. 
     
     
         5 . The Rankine cycle system according to  claim 1 , wherein the controller causes the flow regulating valve to be closed when the charge rate reaches or is smaller than a second predetermined value which is smaller than the first predetermined value. 
     
     
         6 . The Rankine cycle system according to  claim 1 , wherein the bypass passage connects the first passage between the fluid transferring device and the heater to the second passage. 
     
     
         7 . The Rankine cycle system according to  claim 1 , wherein the bypass passage connects the first passage between the heater and the fluid expansion device to the second passage. 
     
     
         8 . The Rankine cycle system according to  claim 1 , wherein the bypass passage connects the first passage to the second passage between the fluid expansion device and the cooling device. 
     
     
         9 . The Rankine cycle system according to  claim 1 , wherein the heater is a cooling water boiler in which the working fluid is heated through heat exchange with engine cooling water and/or a waste gas boiler in which the working fluid is heated through heat exchange with exhaust gas.