JP2009156039A - External combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a heating efficiency by a heater. <P>SOLUTION: An external combustion engine includes a tubular container 10 into which an working medium 14 is flowably sealed in a liquid state, a heater 15 arranged at one end side of the container 10, for heating to evaporate the working medium 14 by externally supplied heat, a cooler 19, arranged at the other end side of the arrangement area of the heater 15 in the container 10, for cooling to condensate vapor of the working medium 14 evaporated by the heater 15, and an output unit 11, communicating with the other end portion of the container 10, for converting displacement of liquid portion of the working medium 14 caused by volume fluctuations of the working medium 14 associated with evaporation and condensation of the working medium 14 into mechanical energy, and outputting it. The heater 15 is formed such that areas near the cooler 19 have thick wall, and areas apart from the cooler 19 have thin wall. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an external combustion engine that displaces a liquid portion of a working medium by evaporation and condensation of the working medium, converts the displacement of the liquid portion of the working medium into mechanical energy, and outputs the mechanical energy.

  Conventionally, this type of external combustion engine, also called a liquid piston steam engine, encloses a working medium in a tubular container so as to be able to flow in a liquid phase, and is in a liquid phase state by a heater arranged at one end of the container. A part of the working medium is heated to evaporate, the working medium vapor is cooled and condensed by a cooler disposed in the middle of the container, and the liquid part of the working medium is cycled by evaporation and condensation of the working medium. The self-excited vibration of the working medium is extracted as mechanical energy at an output portion that is displaced (so-called self-excited vibration) and communicates with the other end of the container (for example, Patent Document 1). .

  In the prior art of Patent Document 1, the heater is formed in a cylindrical shape extending in the vertical direction, and a space formed on the inner surface side of the cylindrical heater heats the working medium to evaporate. Is configured. The cylindrical heater has a constant inner diameter and an outer diameter, and a constant thickness.

Similarly, the cooler is also formed in a cylindrical shape extending in the vertical direction, and a space formed on the inner surface side of the cylindrical cooler constitutes a cooling unit that cools and condenses the working medium.
JP-A-2005-330909

  By the way, in the said prior art, since a working medium vibrates self-excited, the time in which the liquid part of a working medium exists differs in the lower part near a cooling part among heating parts, and the upper part away from the cooling part. More specifically, the time in which the liquid portion of the working medium exists becomes longer in the lower part closer to the cooling part. As a result, the amount of heat exchanged with the working medium increases in the lower part of the heater, and the amount of heat exchanged with the working medium decreases in the upper part of the heater.

  On the other hand, in the above prior art, since the thickness of the cylindrical heater is constant, the heater has the same heat capacity in the lower part and the upper part.

  For this reason, in the lower part of the heater where the amount of heat exchanging heat with the working medium is lower than that of the upper part where the amount of heat exchanging heat with the working medium is low, the heating efficiency of the heater is reduced. There's a problem.

  An object of this invention is to improve the heating efficiency by a heater in view of the said point.

In order to achieve the above object, in the invention described in claim 1, a tubular container (10) in which a working medium (14) is encapsulated so as to be able to flow in a liquid state;
A heater (15) disposed at one end of the container (10) and evaporating by heating the working medium (14) with heat supplied from outside;
A cooler (19) which is disposed on the other end side of the container (10) with respect to the arrangement portion of the heater (15) and cools and condenses the vapor of the working medium (14) evaporated by the heater (15); ,
Displacement of the liquid part of the working medium (14) caused by the volume fluctuation of the working medium (14) due to evaporation and condensation of the working medium (14) is communicated with the other end of the container (10) into mechanical energy. And an output unit (11) for outputting
The heater (15) is characterized in that the portion close to the cooler (19) is thick and the portion away from the cooler (19) is thin.

  According to this, since the site | part close | similar to a cooler (19) has comprised the heater (15), the heat capacity of the site | part close | similar to a cooler (19) among heaters (15) can be enlarged. For this reason, since the temperature fall in the site | part close | similar to a cooler (19) among heaters (15) can be suppressed, the heating efficiency of a heater (15) can be improved.

  In addition, since the heater (15) has a thin portion away from the cooler (19), the thickness of the heater (15) away from the cooler (19) becomes excessive. Thus, it is possible to reduce the size and weight.

In the invention according to claim 2, in the external combustion engine according to claim 1, the heater (15) has a closed cross section (15a) for heating the working medium (14) on the inner surface side,
The closed cross section (15a) is characterized in that a portion close to the cooler (19) has a large cross sectional area and a portion away from the cooler (19) has a small cross sectional area.

  According to a third aspect of the present invention, in the external combustion engine according to the second aspect, the closed cross section (15a) has an outer surface as it goes from a side away from the cooler (19) toward a side closer to the cooler (19). Has a shape that expands outward.

  According to a fourth aspect of the present invention, in the external combustion engine according to the second aspect, the closed cross section (15a) has an inner surface as it goes from a side closer to the cooler (19) to a side away from the cooler (19). It has the shape which becomes depressed toward the outer surface side, It is characterized by the above-mentioned.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the present embodiment, an external combustion engine (liquid piston steam engine) according to the present invention is applied to a power generator mounted on a vehicle.

  FIG. 1 is a cross-sectional view showing a schematic configuration of the liquid piston steam engine according to the present embodiment, and the up and down arrows in FIG. 1 indicate the vertical direction in the installed state of the liquid piston steam engine. FIG. 2 is an enlarged view of a main part of FIG.

  The liquid piston steam engine according to the present embodiment includes a container 10 and a generator 11 that forms an output unit. The generator 11 houses a mover 13 in which a permanent magnet is embedded in a casing 12, and generates an electromotive force when the mover 13 is displaced by vibration.

  The container 10 is a tubular pressure container in which a working medium (in this example, water) 14 is sealed so as to be able to flow in a liquid state. It is formed in a shape. In this example, the container 10 is made of stainless steel.

  The generator 11 is disposed at one end of a substantially U-shaped container 10, and the other end of the container 10 is heated to heat the working medium 14 using a high-temperature fluid (exhaust gas in this example) as a heating source. A container 15 is arranged. The heater 15 is made of a material having excellent thermal conductivity (in this example, copper).

  The heater 15 can be integrally formed. Alternatively, the heater 15 may be formed by dividing the heater 15 into a plurality of divided bodies and then integrally fastening the plurality of divided bodies with fastening means such as screws.

  The heater 15 has a cylindrical closed section 15a extending in the vertical direction, and heats the working medium 14 on the inner surface side of the closed section 15a. The lower part of the internal space of the closed cross section 15a constitutes a heating unit 16 that heats and evaporates the liquid working medium 14, and the upper part of the internal space of the closed cross section 15a is the vapor of the working medium 14. Constitutes a steam reservoir 17 for accumulating water.

  The outer diameter of the cylindrical closed cross-section portion 15a continuously increases from the upper side to the lower side, and the outer surface of the closed cross-section portion 15a increases radially outward as it goes from the upper side to the lower side. ing. On the other hand, the inner diameter of the cylindrical closed section 15a is substantially constant.

  Thereby, as for the closed cross-section part 15a, the lower part has a large cross-sectional area and the upper part has a small cross-sectional area. In other words, the heater 15 is formed such that the lower part is thick and the upper part is thin.

  The upper portion (thin wall portion) of the heater 15 has a thickness that can withstand the vapor pressure of the working medium 14. Although not shown, the heater 15 is supplied with heat from exhaust gas (hot gas) discharged from the engine (internal combustion engine) of the vehicle.

  A portion of the internal space of the container 10 located below the heater 15 constitutes a cooling unit 18 that cools and condenses the vapor of the working medium 14 evaporated by the heating unit 16. A cooler 19 in which cooling water for cooling a vehicle engine (internal combustion engine) circulates is disposed in contact with the outer peripheral surface of the container 10 in the cooling unit 18 so as to be able to conduct heat.

  In the casing 12 of the generator 11, a piston 20 that is displaced by receiving pressure from the liquid portion of the working medium 14 is slidably disposed on the cylinder portion 21. The piston 20 is connected to a shaft 22, and a coil spring 23 that generates an elastic force so as to push back the piston 20 once pushed out is provided at the end of the shaft 22 opposite to the piston 20. Yes. The above-described movable element 13 is connected to the shaft 22, and the movable element 13 is also displaced by vibration when the shaft 22 is displaced by vibration.

  Next, the operation in the above configuration will be described. When the heater 15 and the cooler 19 are operated, first, the working medium 14 in the liquid phase in the heating unit 16 is heated and evaporated by the heater 15, and the high-temperature and high-pressure is generated in the vapor reservoir 17 and the heating unit 16. The vapor of the working medium 14 is accumulated, and the liquid level 14a of the working medium 14 is pushed down. Then, the liquid part of the working medium 14 is displaced toward the piston 20 side in the substantially U-shaped container 10 and pushes up the piston 20. At this time, the coil spring 23 is elastically compressed.

  Next, when the liquid level 14a of the working medium 14 falls to the cooling unit 18 and the vapor of the working medium 14 enters the cooling unit 18, the vapor of the working medium 14 is cooled and condensed by the cooler 19, so that The force to push down the liquid level 14a of the medium 14 disappears.

  Then, the piston 20 on the generator 11 side once pushed up by the expansion of the vapor of the working medium 14 is lowered by the elastic restoring force of the coil spring 23, and the liquid portion of the working medium 14 heats the inside of the substantially U-shaped container 10. Displacement toward the portion 16 side. Then, the liquid level 14 a of the working medium 14 in the container 10 rises to the heating unit 16.

  Such an operation is repeatedly executed until the operations of the heater 15 and the cooler 19 are stopped. During this time, the working medium 14 in the container 10 is periodically displaced (so-called self-excited vibration), and the mover of the generator 11 is moved. 13 is moved up and down.

  That is, by alternately and repeatedly generating and condensing the vapor of the working medium 14, the liquid portion of the working medium 14 is self-excited and vibrated as a liquid piston, and the self-excited vibration displacement of the liquid piston is extracted as an output.

  As can be seen from the above description, the time in which the liquid portion of the working medium 14 exists is different between the lower part of the heating part 16 near the cooling part 18 and the upper part away from the cooling part 18. That is, in the heating unit 16, the time in which the liquid portion of the working medium 14 exists becomes longer as the lower part is closer to the cooling unit 18.

  As a result, the amount of heat exchanged with the working medium 14 increases in the lower part of the heater 15, and the amount of heat exchanged with the working medium 14 decreases in the upper part of the heater 15.

  In view of this point, in this embodiment, since the heat capacity of the lower part of the heater 15 is increased by making the lower part of the heater 15 thick, the working medium 14 and the heat of the heater 15 are increased. It is possible to suppress a temperature drop in the lower part where a large amount of heat is exchanged, and thus the heating efficiency of the heater 15 can be improved.

  On the other hand, since the upper part of the heater 15 is made thin, it is possible to avoid the thickness of the upper part of the heater 15 from becoming excessive, and it is possible to reduce the size and weight.

(Second Embodiment)
In the first embodiment, the outer diameter of the closed cross-section portion 15a continuously increases from the upper side toward the lower side. However, in the second embodiment, as shown in FIG. The outer diameter of 15a is increased stepwise from the upper side toward the lower side. Thereby, since the process of the closed cross-section part 15a can be made easy, cost reduction can be aimed at.

(Third embodiment)
In the first embodiment, the outer diameter of the closed section 15a continuously increases from the upper side to the lower side, and the inner diameter of the closed section 15a is substantially constant. In the embodiment, as shown in FIG. 4, the outer diameter of the closed section 15a is substantially constant, and the inner diameter of the closed section 15a is continuously increased from the upper side to the lower side.

  In other words, in the present embodiment, the inner surface of the closed cross-section portion 15a is recessed outward in the radial direction from the lower side toward the upper side.

  Thereby, the same effect as the said 1st Embodiment can be acquired. In addition, in the present embodiment, it is possible to ensure a larger volume of the vapor reservoir 17 than in the first embodiment.

(Fourth embodiment)
In each of the above embodiments, the closed cross section 15a is formed in a cylindrical shape extending in the vertical direction. However, in the fourth embodiment, as shown in FIG. 5, a hollow disk that expands the closed cross section 15a in the horizontal direction. It is formed in a shape.

  The heating part 16 and the vapor reservoir part 17 are configured by mutually independent spaces, and have a circular shape extending in the horizontal direction. And the upper end part of the container 10 is connected to the center part of the heating part 16, and the heating part 16 and the steam reservoir part 17 are mutually connected via the communication path 20. FIG.

  Since the hollow disk-shaped closed cross-section portion 15a has a shape in which the outer surface expands in the vertical direction from the radially outer side toward the radially inner side, the radially inner portion has a large cross-sectional area, and the radially outer side This part has a small cross-sectional area. Therefore, in the heater 15, the radially inner portion is thick, and the radially outer portion is thin.

  According to the present embodiment, the time in which the liquid portion of the working medium 14 exists in the heating unit 16 in the radial direction closer to the cooling unit 18 becomes longer. Although the amount of heat to be exchanged is increased, since the radially inner portion of the heater 15 is thick, the temperature drop of the radially inner portion of the heater 15 can be suppressed. The heating efficiency can be improved.

  Further, in the present embodiment, when the vapor of the working medium 14 is cooled and condensed by the cooler 19 and the liquid level 14 a of the working medium 14 rises, the liquid portion of the working medium 14 collides with the upper wall surface of the heating unit 16. .

  Thereby, since the working medium 14 in the heating part 16 is stirred and a turbulent flow is generated, the temperature boundary layer in the heating part 16 can be destroyed. As a result, the heating efficiency of the heater 13 can be further improved.

(Other embodiments)
In each of the above embodiments, the case where the present invention is applied to the drive source of the power generation apparatus has been described. However, the external combustion engine of the present invention can also be used as a drive source other than the power generation apparatus.

It is sectional drawing which shows schematic structure of the external combustion engine by 1st Embodiment of this invention. It is a principal part enlarged view of FIG. It is sectional drawing which shows the principal part of the external combustion engine by 2nd Embodiment. It is sectional drawing which shows the principal part of the external combustion engine by 3rd Embodiment. It is sectional drawing which shows the principal part of the external combustion engine by 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Container 11 Output part 14 Working medium 15 Heater 15a Closed cross-section part 19 Cooler

Claims (4)

A tubular container (10) in which a working medium (14) is encapsulated so as to be able to flow in a liquid state;
A heater (15) disposed on one end side of the container (10) and heating and evaporating the working medium (14) with heat supplied from outside;
A cooler that is disposed on the other end side of the container (10) with respect to the heater (15) and cools and condenses the vapor of the working medium (14) evaporated by the heater (15). (19)
Displacement of the liquid part of the working medium (14), which is communicated with the other end of the container (10) and caused by volume fluctuation of the working medium (14) due to evaporation and condensation of the working medium (14), is mechanically performed. An output unit (11) for converting into energy and outputting,
The heater (15) is formed so that a portion close to the cooler (19) is thick and a portion away from the cooler (19) is thin. organ. The heater (15) has a closed cross section (15a) for heating the working medium (14) on the inner surface side,
The closed cross section (15a) is formed so that a portion close to the cooler (19) has a large cross-sectional area and a portion away from the cooler (19) has a small cross-sectional area. The external combustion engine according to claim 1.   The closed cross section (15a) has a shape in which an outer surface expands outward as it goes from a side away from the cooler (19) toward a side closer to the cooler (19). The external combustion engine according to claim 2.   The closed cross section (15a) has a shape in which the inner surface is recessed toward the outer surface side from the side closer to the cooler (19) toward the side away from the cooler (19). The external combustion engine according to claim 2, wherein the engine is an external combustion engine.