JP2014001667A - Rankine cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Rankine cycle device capable of always obtaining a constant lubrication oil supply amount with a simple constitution.SOLUTION: A Rankine cycle device comprises: a pump 1; an evaporator 2; an expander 3; a condenser 4; an oil separator 7; a lubrication oil flow passage 8 extending from the oil separator 7 to the expander 3; a variable throttle device 9 having a variable throttle valve 90 provided in the middle of the lubrication oil flow passage, and operation fluid pressure detection means 91 for detecting a pressure of operation fluid in the expander; and a stationary throttle section provided on the lubrication oil flow passage on a downstream side of the variable throttle valve in series with the variable throttle valve. The variable throttle device controls a pressure of lubrication oil on an outlet side so that a differential pressure between the pressure of the lubrication oil on the outlet side of the variable throttle valve and a low pressure of the operation fluid on the emission side of the expander becomes constant.

Description

  The present invention relates to a Rankine cycle apparatus, and more particularly, to a Rankine cycle apparatus in which lubricating oil separated from a working fluid is supplied to an expander.

  Patent Document 1 discloses a Rankine cycle apparatus that separates and collects lubricating oil mixed in a working fluid of the Rankine cycle apparatus and supplies an appropriate amount to an expander and a pump that require lubrication. In the apparatus of Patent Document 1, oil separated by an oil separator disposed downstream of a regenerative heat exchanger is pumped to an expander via a first lubricating oil supply path and via a second lubricating oil supply path. Supplied to each.

  In the embodiment shown in FIG. 1 of Patent Document 1, when the pressure of the working fluid is high, for example, the pressure of the expansion chamber of the expander increases, and the lubricating oil flowing into the lubrication required portion of the expander decreases, resulting in insufficient lubrication. On the other hand, when the pressure of the working fluid is low, the pressure of the expansion chamber of the expander becomes low, and there is a possibility that the lubricating oil flowing into the required lubrication part becomes excessive and the Rankine cycle efficiency is lowered.

  On the other hand, in the embodiment shown in FIG. 2 of Patent Document 1 in particular, a variable throttle mechanism is arranged in the first and second lubricating oil supply passages in order to optimize the amount of lubricating oil supplied to the expander and the pump. And is controlled by the control device so as to obtain an appropriate amount of lubricating oil supplied in accordance with the detected rotational speeds of the expander and the pump. Thereby, it is considered that supply of an appropriate amount of lubricating oil to the expander or the like is realized. However, a relatively complicated configuration including the control device and its program is required.

JP 2009-138684 A

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a Rankine cycle apparatus that can always obtain a constant lubricating oil supply amount with a simple configuration.

  To achieve the above object, the present invention includes a pump (1) for pumping a working fluid, an evaporator (2) for heating the working fluid, an expander (3) for expanding the working fluid to extract power, A condenser (4) that cools the working fluid and a working fluid pipe that connects the pump (1), the evaporator (2), the expander (3), and the condenser (4) to form a working fluid circulation path. An oil separator (7) disposed in the middle of the path (5) and the working fluid line (5) from the evaporator (2) to the expander (3) to separate the lubricating oil from the working fluid; Lubricating oil flow path (8) extending from the oil separator (7) to the required lubrication part of the expander (3), a variable throttle valve (90) provided in the middle of the lubricating oil flow path (8), and the expander A variable throttle device (9, 209) having working fluid pressure detecting means (91, 291) for detecting the pressure of the working fluid in (3); A Rankine cycle device comprising: a fixed throttle portion provided in series with a variable throttle valve (90) in a lubricating oil flow path (8) downstream of the throttle valve (90), wherein the variable throttle device (9, 209) is based on the detected pressure of the working fluid and the difference between the lubricating oil pressure on the outlet side of the variable throttle valve (90) and the low pressure on the discharge side of the expander (3) of the working fluid. Provided is a Rankine cycle device for controlling the lubricant pressure on the outlet side so that the pressure becomes constant.

  According to this, the lubricating oil pressure on the outlet side of the variable throttle valve is increased or decreased in accordance with the increase or decrease of the pressure of the working fluid in the expander, whereby the outlet side lubricating oil pressure and the discharge side of the working fluid in the expander Is controlled to be substantially constant, and as a result, a substantially constant amount of lubricating oil is supplied to the expander.

  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.

It is a mimetic diagram showing composition of a Rankine cycle device by a 1st embodiment of the present invention. It is a typical longitudinal section of a variable throttle valve with which a Rankine cycle device by a 1st embodiment is provided. It is a schematic diagram which shows the structure of the Rankine-cycle apparatus by the 2nd Embodiment of this invention. It is a typical expanded longitudinal cross-sectional view of the direct pressure detection means with which the Rankine cycle apparatus by 2nd Embodiment is provided. It is a mimetic diagram showing the composition of the modification of the Rankine cycle device by a 1st embodiment. It is a modification of the variable throttle valve with which the Rankine cycle apparatus by 1st and 2nd embodiment is provided.

  A Rankine cycle device according to a first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The Rankine cycle device includes a pump 1 that pumps the working fluid to operate the Rankine cycle, and an evaporator 2 that heats the working fluid pumped by the pump 1 by exchanging heat with a high-temperature heat source. The expander 3 that extracts power while expanding the working fluid that has been pressurized by the pump 1 and heated by the evaporator 2, and cools the working fluid decompressed by the expander 3 by exchanging heat with a low-temperature heat source. A condenser 4, a pump 1, an evaporator 2, an expander 3, a working fluid pipe line 5 that forms a working fluid circulation path by connecting the condenser 4, and a rotating electrical machine integrally coupled to the expander 3 6.

  The Rankine cycle device according to the present embodiment includes an oil separator 7 that is disposed between the evaporator 2 and the expander 3 and separates lubricating oil from the working fluid, and requires lubrication of the expander 3 from the oil separator 7. And a variable throttle device 9 provided in the middle of the lubricating oil flow path 8.

  In the present embodiment, for example, high-temperature cooling water or exhaust gas of a vehicle internal combustion engine can be used as the high-temperature heat source, and relatively low-temperature air around the condenser 4 can be used as the low-temperature heat source. Further, for example, a chlorofluorocarbon refrigerant can be used as the working fluid.

  The expander 3 is of a well-known scroll type, and has an uppermost substantially disc-shaped top housing 31 that functions as a fixed scroll 31, a disc-shaped middle housing 32 coupled to the lower portion thereof, and a top housing. 31 and a orbiting scroll 33 disposed between the middle housing 32 and the middle housing 32. The fixed scroll 31 (top housing) and the orbiting scroll 33 have helical tooth portions 31a and 33a that mesh with each other so as to face each other, and an expansion chamber 34 is formed between the helical tooth portions 31a and 33a. Is done.

  The shaft 35 of the expander 3 is shared with the shaft 35 of the rotating electrical machine 6, and the shaft 35 supports the orbiting scroll 33 by a crank portion 35 a that is eccentric from the center axis. Therefore, the orbiting scroll 33 can revolve with a predetermined revolution radius with respect to the central axis of the shaft 35, but at this time, rotation is prevented by a rotation prevention mechanism (not shown).

  The top housing 31 of the expander 3 includes an inflow port 36 and a discharge port 37 for the working fluid. The inflow port 36 is provided in the center and communicates with the expansion chamber 34 on the center side. It is provided in the section and communicates with the expansion chamber 34 on the outer peripheral side. Since the expander 3 is configured as described above, the high-temperature and high-pressure working fluid that has flowed from the inflow port 36 into the expansion chamber 34 on the center side undergoes adiabatic expansion when the expansion chamber 34 sequentially expands toward the outer edge side. As a result, the orbiting scroll 33 and thus the shaft 35 are rotated to generate power, and then flow out from the discharge port 37 on the outer peripheral side toward the condenser 4 in a state where both temperature and pressure are reduced.

  The middle housing 32 of the expander 3 has a lubricating oil inflow port 38 provided on the outer periphery thereof, and a lubricating oil that connects the lubricating oil inflow port 38 and a lubrication required portion such as a bearing portion or a sliding portion in the expander 3. And an internal passage 83. The lubricating oil internal passage 83 includes a fixed throttle portion (not shown) having a reduced flow passage cross-sectional area.

  The rotating electrical machine 6 is coupled to the lower side of the middle housing 32 of the expander 3, and houses the shaft 35 common to the expander 3, the stator 61, the rotor 62 that rotates in the stator 61, and these. A cylindrical rotating electrical machine main housing 63, a substantially disc-shaped bearing housing 64 coupled to the lower side thereof, and a disc-shaped base plate 65 fixed to the lower side thereof are provided. The rotor 62 is a magnet rotor in which a permanent magnet (not shown) is embedded, and is fixed to the shaft 35. The rotating electrical machine main housing 63 supports the upper part of the shaft 35 via an upper ball bearing 66 so as to be rotatable, and the bearing housing 64 supports the lower part of the shaft 35 via a lower ball bearing 67 so as to be rotatable. .

  The rotating electrical machine 6 configured as described above rotates the rotor 62 when electric power is supplied from a battery (not shown) to the stator 61 via an inverter (not shown) when the Rankine cycle apparatus is started. The rotating scroll 33 and the shaft 35 of the expander 3 operate as a generator that generates electric power when rotated by the working fluid.

  The oil separator 7 of the present embodiment is a centrifugal type having a main body formed in a cylindrical shape, and the lubricating oil separated here is sent to the lubricating oil flow path 8, and the lubricating oil is separated. The working fluid is sent to the expander 3 via the working fluid pipe 5.

  The lubricating oil flow path 8 is provided to supply the lubricating oil separated from the working fluid by the oil separator 7 to the expander 3 via the variable throttle device 9. A first lubricating oil passage 81 between the device 9, a second lubricating oil passage 82 between the variable throttle device 9 and the lubricating oil inflow port 38 of the expander 3, and the inside of the lubricating oil in the expander 3 And a passage 83.

  As described above, the variable throttle device 9 is provided in the middle of the lubricating oil flow path 8 from the oil separator 7 to the expander 3, and includes a variable throttle valve 90 and a temperature sensitive cylinder 91 as a working fluid pressure detection means. And a connecting pipe 92 for fluidly connecting them.

  The variable throttle valve 90 includes a substantially cylindrical valve housing 93 that forms a lubricating oil flow chamber 94 therein, a diaphragm 95 coupled to the top of the valve housing 93, and the diaphragm 95 sandwiched between the valve housing 93. And a dome-shaped lid 97 that forms a control pressure chamber 96 in the upper part of the diaphragm 95, and a variable throttle part 98. The variable throttle part 98 includes a circular valve port 101, the valve A substantially conical valve seat 102 that surrounds the mouth 101 and a spherical valve body 104 that is connected to the lower surface of the diaphragm 95 via a stem 103 and is disposed below the valve seat 102.

  Further, the variable throttle valve 90 has a predetermined minimum amount of lubrication even when the valve port 101 is closed by the valve body 104 in addition to the lubricating oil inflow port 99 on the bottom surface and the lubricating oil discharge port 105 on the upper peripheral surface. The valve housing 93 is provided with a bypass passage 106 formed to allow oil to flow, and the control fluid port 107 to which one end of the connection pipe 92 is connected is provided in the lid 97. Therefore, the control pressure chamber 96 of the variable throttle valve 90 is fluidly connected to the temperature sensitive cylinder 91 by the connection pipe 92.

  The temperature sensing cylinder 91 is formed in a cylindrical shape from a metal having high thermal conductivity. A control fluid made of the same type of fluid as the working fluid is sealed in a gas-liquid mixed state in the temperature sensing cylinder 91, the connecting pipe 92, and the control pressure chamber 96 of the variable throttle valve 90. It is desirable that the control fluid is sealed in the gas-liquid mixture in the temperature sensing tube 91 and in the control pressure chamber 96 of the connection line 92 and the variable throttle valve 90.

  In the present embodiment, the temperature sensing cylinder 91 detects the intermediate temperature between the relatively high temperature suction side temperature and the relatively low temperature discharge side temperature of the working fluid expanded by the expander 3. The fixed scroll 31 is attached between the center of the upper surface and the outer edge.

  Since the variable throttle device 9 is configured in this way, a pressure corresponding to the intermediate temperature of the control fluid in the temperature sensing cylinder 91 acts on the control pressure chamber 96 of the variable throttle valve 90, and the lubricating oil circulation chamber. The pressure of the lubricating oil acts on 94. The opening degree of the variable throttle valve 90 is such that the valve body 104 positioned below the valve port 101 moves up and down in the drawing in conjunction with the diaphragm 95, so that the pressure of the lubricating oil acting on the lower surface of the diaphragm 95 and the diaphragm It is determined by the differential pressure with the pressure of the control fluid acting on the upper surface of 95. Further, since the valve body 104 is positioned below the valve port 101, the pressure of the lubricating oil acting on the lower surface of the diaphragm 95 increases with the increase of the pressure of the control fluid, and the pressure of the control fluid decreases. Accordingly, the pressure of the lubricating oil is reduced.

  When the Rankine cycle is activated and the working fluid flows through the working fluid pipe 5, the working fluid is separated from the working fluid by the oil separator 7 provided on the downstream side of the evaporator 2. The Based on the pressure difference between the relatively high pressure in the oil separator 7 and the relatively low pressure of the lubrication required portion in the expander 3, the separated lubricating oil is extracted from the first lubricating oil passage 81. It flows into the expander 3 from the lubricating oil inflow port 38 of the expander 3 via the variable throttle valve 90 and the second lubricant flow passage 82, and the bearing portion via the lubricant internal passage 83 in the expander 3. Or after flowing into a lubrication required part, such as a sliding part, and lubricating there, it merges with a working fluid and flows out of the expander 3 from the discharge port 37 with a working fluid.

  Since the lubricating oil internal passage 83 in the expander 3 is provided with a fixed throttle (not shown), the second lubricating oil on the downstream side of the variable throttle valve 90 because the pressure is reduced when the lubricating oil passes therethrough. The pressure in the flow path 82 is an intermediate pressure, that is, an intermediate pressure between a high pressure in the oil separator 7 and a low pressure at the expander discharge port. Since the flow resistance of the fixed throttle is substantially constant, if the variable throttle valve 90 is controlled so that the differential pressure between the intermediate pressure and the low pressure is substantially constant, the flow into the expander 3 is controlled. Regardless of the change in the pressure of the fluid, it is possible to always supply a substantially constant amount of lubricating oil to the lubrication required portion.

  In the variable throttle valve 90 of the present embodiment, since the spherical valve body 104 connected to the lower surface of the diaphragm 95 by the stem 103 is located below the valve port 101, the temperature of the working fluid flowing into the expander 3 is As a result, when the pressure of the control fluid in the temperature sensing cylinder 91 for detecting the intermediate temperature and thus in the control pressure chamber 96 of the variable throttle valve 90 increases, the valve opening of the variable throttle valve 90 increases. Thus, the intermediate pressure of the lubricating oil acting on the lower surface of the diaphragm 95 also increases. On the contrary, when the temperature of the working fluid flowing into the expander 3 is lowered, the intermediate pressure of the lubricating oil acting on the lower surface of the diaphragm 95 is also lowered due to the reverse action. As a result, the differential pressure between the intermediate pressure of the lubricating oil and the low pressure on the discharge side of the expander 3 can be controlled to be substantially constant.

  Further, in the variable throttle valve 90 of the present embodiment, when the pressure of the working fluid of the expander 3 becomes a predetermined pressure or less, the valve port 101 is closed by the valve body 104, but the bypass passage 106 is provided. Therefore, a certain amount of lubricating oil can be circulated therethrough. Thus, when the pressure of the working fluid of the expander 3 becomes equal to or lower than the predetermined pressure, the variable throttle valve 90 does not perform the above-described control and serves as a fixed throttle that supplies a minimum amount of lubricating oil. work.

  Next, a Rankine cycle device according to a second embodiment of the present invention will be described below with reference to FIGS. The Rankine cycle device according to the second embodiment differs from that of the first embodiment in that the variable throttle device 209 includes a direct pressure detection means 291 instead of the temperature sensitive cylinder 91 as a pressure detection means. However, other configurations are almost the same as shown in FIG. Therefore, the differences will be mainly described below.

  The variable throttle device 209 according to the second embodiment includes a variable throttle valve 90, a direct pressure detection unit 291 and a connection pipe line 92 that fluidly connects them.

  The direct pressure detection means 291 includes a cylinder chamber 292 formed in the fixed scroll 3 of the expander, and a piston 293 slidably disposed in the cylinder chamber 292. The cylinder chamber 292 is partitioned by a piston 293 into a lower first chamber 292a and an upper second chamber 292b. The first chamber 292a is in fluid communication with the expansion chamber 34 of the expander 3, so that the pressure of the working fluid in the expansion chamber 34 acts on the first chamber 292a. In the present embodiment, the first chamber 292a is substantially in the radial direction of the expansion chamber 34 so that the pressure acting on the first chamber 292a is an intermediate pressure between the inflow pressure and the discharge pressure of the working fluid. In fluid communication with the site of

  On the other hand, the second chamber 292 b of the direct pressure detection means 291 is in fluid communication with the control pressure chamber 96 of the variable throttle valve 90 via the connection pipe line 92. The second chamber 292b, the connecting pipe line 92, and the control pressure chamber 96 are filled with hydraulic oil that is an incompressible fluid as a control fluid.

  Since the variable throttle device 209 is configured as described above, it is between the inflow pressure and the discharge pressure of the working fluid in the expansion chamber 34 that acts on the end surface of the piston 293 of the direct pressure detection means 291 on the first chamber 292a side. Is transmitted into the control pressure chamber 96 of the variable throttle valve 90 via hydraulic oil. As a result, also in the second embodiment, the pressure of the lubricating oil acting on the lower surface of the diaphragm 95 of the variable throttle valve 90 increases in accordance with the increase in the pressure of the control fluid that transmits the pressure of the working fluid. As the pressure decreases, the pressure of the lubricating oil decreases.

Other Embodiments In the first embodiment, the temperature sensing cylinder 91 is attached to the upper surface of the fixed scroll 31 of the expander 3, but the temperature sensing cylinder 91 is intermediate between the suction side temperature and the discharge side temperature of the working fluid. It may be attached anywhere as long as the temperature can be detected. For example, as shown in FIG. 5, it may be attached to the working fluid line 5 leading to the expander 3. However, in this case, a thermal resistance member 91 a for temperature compensation is inserted between the surface of the working fluid pipe 5 and the temperature sensing cylinder 91. The thickness and material of the heat resistance member 91a are determined so as to show the intermediate temperature even though the temperature sensing cylinder 91 is attached to the working fluid pipe 5 upstream from the inlet of the expander 3. ing. Further, without using such a heat resistance member 91a, the surface of the working fluid pipe line 5 and the inside of the temperature sensing cylinder 91 can be obtained by increasing the thickness of the temperature sensing cylinder 91 itself or selecting a material having low thermal conductivity. The thermal resistance up to the fluid may be adjusted.

  In the first and second embodiments, the variable throttle valve 90 has a bypass passage 106 to allow a predetermined minimum amount of lubricating oil to flow even when the valve port 101 is closed by the valve body 104. However, instead of such a bypass passage 106, the variable throttle valve 90 may have a stopper 108 as shown in FIG. The stopper 108 protrudes from the valve seat 102 toward the center of the valve port 101 so as to prevent the valve body 104 from contacting the valve seat 102.

  In the first and second embodiments, the variable throttle valve 90 uses the diaphragm 95. However, the variable throttle valve uses a piston slidably disposed in the cylinder chamber instead of the diaphragm. It may be of the type to do. In this case, the pressure of the control pressure chamber acts on one end face of the piston, and the pressure of the lubricating oil circulation chamber acts on the other end face.

DESCRIPTION OF SYMBOLS 1 Pump 2 Evaporator 3 Expander 4 Condenser 5 Working fluid line 7 Oil separator 8 Lubricating oil flow path 9 Variable throttle device 90 Variable throttle valve 91 Working fluid pressure detection means

Claims (4)

A pump (1) for pumping the working fluid;
An evaporator (2) for heating the working fluid;
An expander (3) that expands the working fluid and extracts power;
A condenser (4) for cooling the working fluid;
A working fluid line (5) connecting the pump (1), the evaporator (2), the expander (3), and the condenser (4) to form a circulation path of the working fluid;
An oil separator (7) disposed in the middle of the working fluid line (5) from the evaporator (2) to the expander (3) for separating lubricating oil from the working fluid;
A lubricating oil flow path (8) extending from the oil separator (7) to a lubrication required portion of the expander (3);
A variable throttle device having a variable throttle valve (90) provided in the middle of the lubricating oil passage (8) and a working fluid pressure detecting means (91, 291) for detecting the pressure of the working fluid in the expander (3). (9,209),
A Rankine cycle device comprising: a fixed throttle portion provided in series with the variable throttle valve (90) in the lubricating oil flow path (8) downstream of the variable throttle valve (90). ,
Based on the pressure of the working fluid detected by the variable throttle device (9, 209), the lubricating oil pressure on the outlet side of the variable throttle valve (90) and the low pressure on the discharge side of the working fluid in the expander (3) are reduced. The Rankine cycle device, wherein the outlet side lubricating oil pressure is controlled so that a differential pressure between the pressure and the pressure is constant. The working fluid pressure detection means (91) comprises a temperature sensing tube (91),
The variable throttle valve (90) includes a diaphragm (95), a control pressure chamber (96) provided on one side of the diaphragm (95), and a lubricating oil circulation chamber (94) provided on the other side. Have
The temperature sensing cylinder (91) is filled with a control fluid that is the same type of fluid as the working fluid in a gas-liquid mixed state, and is intermediate between the inlet temperature and the outlet temperature of the working fluid in the expander (3). Arranged to detect temperature, and in fluid communication with the control pressure chamber (96) of the variable throttle valve (90) via the control fluid;
The variable throttle valve (90) opens the variable throttle valve according to a differential pressure between the pressure of the control fluid acting on one side surface of the diaphragm (95) and the pressure of the lubricating oil acting on the other side surface. The Rankine cycle apparatus according to claim 1, wherein the degree is adjusted. The working fluid pressure detection means (291) comprises direct pressure detection means (291),
The direct pressure detection means (291) includes a cylinder chamber (292) and a piston (293) slidably disposed in the cylinder chamber (292).
The cylinder chamber (292) is partitioned into a first chamber (292a) and a second chamber (292b) by the piston (293), and the first chamber (292a) is used for working fluid in the expander (3). The intermediate chamber is in fluid communication with the expansion chamber (34) of the expander (3) so that an intermediate pressure between the inflow pressure and the discharge pressure acts, and the second chamber (292b) reduces the intermediate pressure to the variable throttle. In fluid communication with the control pressure chamber (96) via an incompressible control fluid to communicate to the control pressure chamber (96) of a valve (90);
The variable throttle valve (90) has an opening degree of the variable throttle valve according to a differential pressure between the pressure of the control fluid acting on one side surface of the diaphragm (95) and the pressure of the lubricating oil acting on the other side surface. The Rankine cycle apparatus according to claim 1, wherein   The variable throttle valve (90) serves as a fixed throttle that maintains a certain minimum opening degree when a pressure acting on the control pressure chamber (96) is a predetermined value or less. The Rankine cycle apparatus according to claim 1.

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