Waste heat collecting apparatus

Abstract

A waste heat collecting apparatus has a loop-type heat pipe, which has a vaporizing portion arranged in an area for exhaust gas passage and a condensing portion provided in a water tank, through which coolant foran engine flows. Working fluid is circulated from the vaporizing portion to the condensing portion and back to the vaporizing portion. A valve device is provided at a downstream side of the condensing portion, wherein the valve device is operated to open or close a fluid passage for the working fluid depending on an inner pressure of the heat pipe.

1 . A waste heat collecting apparatus for an automotive vehicle comprising: 
 a loop-type heat pipe having; 
 a vaporizing portion arranged in an area for exhaust gas passage for vaporizing working fluid filled in the heat pipe with heat contained in exhaust gas from an engine;  
 a condensing portion for condensing working fluid, which is vaporized in the vaporizing portion, by coolant for the engine; and  
 a connecting passage for connecting the condensing portion with the vaporizing portion,  
   a valve device provided in the connecting passage between the condensing portion and the vaporizing portion for opening or closing the connecting passage,    wherein the valve device has a driving portion and a valve body connected with the driving portion for opening or closing the connecting passage,    the driving portion being operated by at least one of the operating parameters, which comprises 
 inner pressure of the working fluid in the heat pipe,  
 temperature of the working fluid in the heat pipe, and  
 temperature of the coolant, and  
   wherein the valve device is provided at a downstream side of the condensing portion or an upstream side of the vaporizing portion.    
   
   
       2 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the valve device has a hysteresis for an opening and closing operation of the valve body.    
   
   
       3 . A waste heat collecting apparatus according to  claim 2 , wherein 
 the driving portion is operated by the inner pressure of the working fluid in the heat pipe,    the valve body closes the connecting passage when the inner pressure is higher than a first predetermined pressure, and    the valve body opens the connecting passage when the inner pressure is lower than a second predetermined pressure,    wherein the first predetermined pressure is higher than the second predetermined pressure.    
   
   
       4 . A waste heat collecting apparatus according to  claim 3 , wherein 
 the first predetermined pressure is 0.1 MPa, and    the second predetermined pressure is 0.05 MPa.    
   
   
       5 . A waste heat collecting apparatus according to  claim 3 , wherein 
 water is used as the working fluid for the heat pipe,    the first predetermined pressure is 0.1 MPa, and    the second predetermined pressure is 0.6 kPa.    
   
   
       6 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the valve device has a bypass aperture such that a small amount of the working fluid is circulated from the condensing portion to the vaporizing portion even when the valve body is moved to its closed position.    
   
   
       7 . A waste heat collecting apparatus according to  claim 1 , further comprising: 
 a heat insulating portion provided between the vaporizing portion and the condensing portion for insulating the condensing portion from the vaporizing portion.    
   
   
       8 . A waste heat collecting apparatus according to  claim 7 , wherein 
 the heat insulating portion is formed by multiple air spaces formed at a heat insulating plate, which is provided between the vaporizing portion and the condensing portion.    
   
   
       9 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the connecting passage is arranged at such a portion, which is outside of the area for the exhaust gas passage.    
   
   
       10 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the connecting passage is arranged in the area for the exhaust gas passage.    
   
   
       11 . A waste heat collecting apparatus according to  claim 10 , further comprising: 
 a heat insulating wall provided at an upstream side of the connecting passage with respect to the exhaust gas flow.    
   
   
       12 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the vaporizing portion has multiple tubes arranged in the area for the exhaust gas passage, such that longitudinal direction of the tubes is arranged in a vertical direction,    the condensing portion is arranged at an upper side of the vaporizing portion and arranged in a coolant passage through which the coolant for the engine flows, and    the connecting passage is a return pipe, a longitudinal length of which is almost equal to that of the tubes ( 111 ) of the vaporizing portion.    
   
   
       13 . A waste heat collecting apparatus according to  claim 12 , wherein 
 the vaporizing portion comprises multiple tube lines, each having multiple tubes, wherein the tube lines are arranged in a direction of the exhaust gas flow, and    the return pipe is arranged at a downstream side of the multiple tube lines.    
   
   
       14 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the vaporizing portion comprises; 
 multiple tubes arranged in an area for the exhaust gas passage,  
 such that longitudinal direction of the tubes is arranged in a vertical direction,  
 a first header portion for collecting the working fluid from the tubes, and  
 a second header portion for distributing the condensed working fluid, which is condensed at the condensing portion,  
 into the tubes,  
   the condensing portion is arranged in a coolant passage through which the coolant for the engine flows, and    the condensing portion is respectively connected to the first and second header portions through the connecting passage.    
   
   
       15 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the driving portion of the valve device has a diaphragm, which is displaced depending on the inner pressure of the working fluid for the heat pipe.    
   
   
       16 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the driving portion of the valve device has a thermo-wax portion, which is displaced depending on the temperature of the working fluid for the heat pipe or the temperature of the coolant for the engine.    
   
   
       17 . A waste heat collecting apparatus according to  claim 16 , wherein 
 the valve device has the thermo-wax portion expanded or contracted depending on the temperature of the coolant,    the valve body comprises a bellows having one opened end connected to the thermo-wax portion, wherein the other end of the bellows is closed, and    a communication port is provided in the valve device so that a part of the coolant enters into the inside space of the bellows.    
   
   
       18 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the connecting passage has a fluid flow-in passage for allowing the working fluid vaporized at the vaporizing portion to flow into the condensing portion, and a fluid flow-out passage for returning the condensed working fluid condensed at the condensing portion to the vaporizing portion,    the fluid flow-in and flow-out passages are arranged closer to each other, and    the fluid flow-in passage is arranged at a position higher in a vertical direction than a liquid level of the working fluid in the vaporizing portion, which corresponds to a liquid level of the working fluid when the heat collecting apparatus is not in its operation.    
   
   
       19 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the connecting passage is formed by a single pipe, which is arranged at a position higher in a vertical direction than a liquid level of the working fluid in the vaporizing portion, which corresponds to a liquid level of the working fluid when the heat collecting apparatus is not in its operation.    
   
   
       20 . A waste heat collecting apparatus according to  claim 19 , wherein 
 a partitioning wall provided in the pipe for separating a space of the pipe into an upper space for the working fluid and a lower space for the condensed working fluid, so that the condensed working fluid is not directly contacted with the working fluid.    
   
   
       21 . A waste heat collecting apparatus according to  claim 1 , wherein 
 the valve device is arranged at a position higher in a vertical direction than a liquid level of the working fluid in the vaporizing portion, which corresponds to a liquid level of the working fluid when the heat collecting apparatus is not in its operation.    
   
   
       22 . A waste heat collecting apparatus according to  claim 1 , wherein 
 a reverse flow preventing means is provided in the condensing portion, so that a reverse flow of the condensed working fluid to the vaporizing portion is suppressed.    
   
   
       23 . A waste heat collecting apparatus according to  claim 22 , wherein 
 the reverse flow preventing means is formed by a plate member, which is inclined in a flow direction of the working fluid.    
   
   
       24 . A waste heat collecting apparatus according to  claim 22 , wherein 
 the reverse flow preventing means is formed as a restricting portion, so that an inner diameter of a fluid passage for the working fluid is made smaller.    
   
   
       25 . A waste heat collecting apparatus having a loop-type heat pipe comprising: 
 a vaporizing portion arranged in an area for exhaust gas passage for vaporizing working fluid filled in the heat pipe with heat contained in exhaust gas from an engine, wherein the vaporizing portion having multiple tubes vertically extending, and a lower and an upper header tank portion provided at both longitudinal ends of the multiple tubes;    a water tank provided at an upper side of the vaporizing portion, through which coolant for the engine flows;    a condensing portion provided in an inside of the water tank for condensing working fluid, which is vaporized in the vaporizing portion, by means of heat exchange with the coolant flowing through the water tank, wherein an upstream end of the condensing portion is connected with the upper header tank portion and a downstream end of the condensing portion is operatively connected to the lower header tank portion;    a condensed water return portion provided between the downstream end of the condensing portion and the lower header tank portion; and    a valve device provided in the water tank for opening or closing a fluid passage between the downstream end of the condensing portion and the condensed water return portion, wherein the valve device has a driving portion and a valve body connected with the driving portion for opening or closing the fluid passage, and the driving portion is operated by an inner pressure of the working fluid in the heat pipe.    
   
   
       26 . A waste heat collecting apparatus having a loop-type heat pipe comprising: 
 a vaporizing portion arranged in an area for exhaust gas passage for vaporizing working fluid filled in the heat pipe with heat contained in exhaust gas from an engine, wherein the vaporizing portion having multiple tubes vertically extending, and a lower and an upper header tank portion provided at both longitudinal ends of the multiple tubes;    a water tank provided at a horizontal side of the vaporizing portion, through which coolant for the engine flows;    a condensing portion provided in an inside of the water tank for condensing working fluid, which is vaporized in the vaporizing portion, by means of heat exchange with the coolant flowing through the water tank, wherein an upstream end of the condensing portion is connected with the upper header tank portion and a downstream end of the condensing portion is operatively connected to the lower header tank portion; and    a valve device provided in the water tank at a downstream side of the condensing portion for opening or closing a fluid passage between the downstream end of the condensing portion and the lower header tank portion, wherein the valve device has a driving portion and a valve body connected with the driving portion for opening or closing the fluid passage, and the driving portion is operated by an inner pressure of the working fluid in the heat pipe.