US20150098845A1

US20150098845A1 - Fluid Machinery

Info

Publication number: US20150098845A1
Application number: US14/399,456
Authority: US
Inventors: Shinji Nakamura
Original assignee: Sanden Holdings Corp
Current assignee: Sanden Corp
Priority date: 2012-05-08
Filing date: 2013-05-02
Publication date: 2015-04-09
Also published as: CN104271951A; DE112013002403T5; JP2013234585A; WO2013168682A1; JP5984492B2

Abstract

A fluid machinery including: an expander that generates power by expansion of refrigerant; and a piston pump that pumps the refrigerant, and capable of reducing a decrease in lubrication performance of a mechanical sliding section in a crank chamber of the piston pump. A fluid machinery 29A includes an expander unit (scroll expander) 60A that generates power by expansion of refrigerant, and a pump unit (piston pump) 50A that pumps the refrigerant. A rotating shaft 28 of the fluid machinery 29A functions as an output shaft of the expander unit 60A and a drive shaft of the pump unit 50A. The rotating shaft 28 has a crank section 28 a housed in the crank chamber 72A. A refrigerant outlet chamber 78A, through which the expanded refrigerant is discharged from the expander unit 60A, communicates with the crank chamber 72A via a bearing 71 b, a housing space of a driven crank mechanism 80, and an anti-rotation member 77.

Description

TECHNICAL FIELD

The present invention relates to a fluid machinery used by being incorporated into a Rankine cycle or the like, in particular, relates to a fluid machinery that is provided with an expander that generates power by expansion of a refrigerant, and a piston pump that pumps the refrigerant.

BACKGROUND ART

As a fluid machinery incorporated into a Rankine cycle, a pump-integrated expander in which an expander that generates power by expansion of a refrigerant is integrally connected to a pump that pumps the refrigerant has been known (for example, see Patent Document 1). Inventors have considered adopting a piston pump, with high volumetric efficiency from a low rotational speed area to a high rotational speed area, as a pump of the fluid machinery of this type. In this case, a liquid-phase refrigerant drawn into the piston pump might flow into a crank chamber, and thus, there may be a concern over degradation of a lubrication state of each sliding section in the crank chamber.
On this point, Patent Document 2 discloses, in a fluid machinery incorporated into a Rankine cycle, a technique of sufficiently lubricating a mechanical sliding section of a refrigerant pumping pump, by separating a lubricating oil from a gas-phase refrigerant, and by supplying the separated lubricating oil to a liquid-phase refrigerant drawn into the refrigerant pumping pump.

REFERENCE DOCUMENT LIST

Patent Document

Patent Document 1: Japanese Patent Application Laid-open Publication No. 2010-077827
Patent Document 2: Japanese Patent No. 4725344

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the lubricating oil separated from the gas-phase refrigerant has a high temperature compared to the drawn refrigerant of the pump, and thus, as in the above-described related art, if the lubricating oil separated from the gas-phase refrigerant is supplied to the liquid-phase refrigerant drawn into the refrigerant pumping pump, a part of the drawn refrigerant of the pump is gasified (evaporated), and there may be a risk of a decrease in the volumetric efficiency of the pump.
Therefore, an object of the present invention is to reduce a risk of a decrease in the volume efficiency of a piston pump, while reducing a decrease in lubrication performance of a mechanical sliding section in a crank chamber of the piston pump, in a fluid machinery including an expander that generates power by the expansion of the refrigerant, and the piston pump that pumps the refrigerant.

Means for Solving the Problems

A fluid machinery according to an aspect of the invention including: an expander that generates power by expansion of a refrigerant; and a piston pump that pumps the refrigerant, in which a refrigerant outlet chamber through which the refrigerant after expansion is discharged from the expander communicates with a crank chamber of the piston pump.

Effects of the Invention

According to the fluid machinery, since the interior of the crank chamber is set to a state in which the liquid-phase refrigerant is easily gasified, by allowing the refrigerant outlet section, through which the refrigerant after expansion is discharged from the expander, to communicate with the crank chamber of the piston pump, it is possible to reduce an amount of liquid-phase refrigerant that flows into the crank chamber and/or is stored in the crank chamber. Furthermore, there is little fear of gasification of the drawn refrigerant of the pump as in the above-described related arts. This can reduce the risk of a decrease in volumetric efficiency of the piston pump, while reducing a decrease in lubrication performance of the mechanical sliding section of the piston pump.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a schematic configuration of an exhaust heat recovery apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a fluid machinery (pump-integrated expander) according to the first embodiment.

FIG. 3 is a diagram illustrating an example of a distribution passage of a gas-phase refrigerant in the fluid machinery (pump-integrated expander) according to the first embodiment.

FIGS. 4A and 4B are diagrams illustrating modified examples of the fluid machinery (pump-integrated expander) according to the first embodiment.

FIG. 5 is a diagram illustrating a schematic configuration of an exhaust heat recovery apparatus of a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a fluid machinery (expander-pump-generator motor-integrated fluid machinery) according to the second embodiment.

FIG. 7 is a diagram illustrating an example of the distribution passage of a gas-phase refrigerant in the fluid machinery (expander-pump-generator motor-integrated fluid machinery) according to the second embodiment.

FIG. 8 is a diagram illustrating a modified example of a fluid machinery (expander-pump-generator motor-integrated fluid machinery) according to the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 illustrates a schematic configuration of an exhaust heat recovery apparatus 1A to which a fluid machinery according to the present invention is applied in a first embodiment. The exhaust heat recovery apparatus 1A is mounted on a vehicle and recovers and uses exhaust heat of an engine 10 of the vehicle.
The exhaust heat recovery apparatus 1A has a Rankine cycle 2A that recovers the exhaust heat of the engine 10 and converts it into power, a transmission mechanism 3 that performs the transmission of power between the Rankine cycle 2A and the engine 10, and a control unit 4A that controls the overall operation of the exhaust heat recovery apparatus 1.
The engine 10 is a water-cooled internal combustion engine and is cooled by an engine cooling water that circulates in a cooling water flow passage 11. A heater 22 of the Rankine cycle 2A to be described later is disposed on the cooling water flow passage 11, so that the engine cooling water that has absorbed heat from the engine 10 flows through the heater 22.
The Rankine cycle 2A recovers the exhaust heat (here, heat of the engine cooling water) of the engine 10 as an external heat source, and converts the exhaust heat into power and outputs the power.
In a refrigerant circulation passage 21 of the Rankine cycle 2A, the heater 22, an expander 23, a condenser 24, and a pump 25 are disposed in this order. Furthermore, between the heater 22 and the condenser 24, a bypass passage 26 that circulates the refrigerant while bypassing the expander 23 is provided, and a bypass valve 27 that opens and closes the bypass passage 26 is provided in the bypass passage 26.
The heater 22 is a heat exchanger which heats the refrigerant to obtain superheated vapor, by performing heat exchange between the engine cooling water which has absorbed heat from the engine 10 and the refrigerant of the Rankine cycle 2A. Alternatively, although it is not illustrated, the heater 22 may be configured to perform heat exchange between the refrigerant and the exhaust gas of the engine 10, instead of the engine cooling water.
The expander 23 is a scroll expander that generates power (driving force) by expanding the refrigerant (gas-phase refrigerant), which is the superheated vapor heated by the heater 22, and by converting it into rotational energy.
The condenser 24 is a heat exchanger which cools and condenses (liquefies) the refrigerant, by performing the heat exchange between the refrigerant passed through the expander 23 and the ambient air.
The pump 25 is a mechanical type piston pump that pumps the refrigerant (liquid-phase refrigerant) liquefied by the condenser 24. When the pump 25 draws and discharges the refrigerant (liquid-phase refrigerant) liquefied in the condenser 24, the refrigerant circulates through each of the elements of the Rankine cycle 2A.
Here, the expander (scroll expander) 23 and the pump (piston pump) 25 are integrally connected to each other and is configured as a “pump-integrated expander” 29A having a common rotating shaft 28. That is, the rotating shaft 28 of the pump-integrated expander 29A has a function as an output shaft of the expander 23 and a function as a drive shaft of the pump 25.
The transmission mechanism 3 has a pulley 32 that is attached to the rotating shaft 28 of the pump-integrated expander 29A via an electromagnetic clutch 31, a crank pulley 33 that is attached to a crankshaft 12 of the engine 10, and a belt 34 that is wrapped around the pulley 32 and the crank pulley 33.
The control unit 4A controls the operation of the bypass valve 27 and the electromagnetic clutch 31.
When the control unit 4A opens the bypass valve 27, the refrigerant circulates while bypassing the expander 23. Furthermore, the control unit 4 controls to turn on (engage) and turn off (disengage) the electromagnetic clutch 31, so that the transmission mechanism 3 transfers and cuts off power between the engine 10 and the Rankine cycle 2A (more specifically, the pump-integrated expander 29A).
When starting up the Rankine cycle 2A, the control unit 4A opens the bypass valve 27 and drives the pump 25 by the engine 10 by turning on (engage) the electromagnetic clutch 31. Thus, the refrigerant is circulated while bypassing the expander 23. Then, for example, when a pressure difference before and after the expander 23 becomes a predetermined value or more, the control unit 4A closes the bypass valve 27 and causes the refrigerant to circulate via the expander 23. Thereafter, when the expander 23 generates sufficient driving force, a part of the driving force generated by the expander 23 drives the pump 25, the remaining driving force is transmitted to the engine 10 via the transmission mechanism 3 to assist the output (driving force) of the engine 10.
Furthermore, for example, by turning off (disengage) the electromagnetic clutch 31, the control unit 4A is able to stop the Rankine cycle 2A.
Next, a configuration of the pump-integrated expander 29A (fluid machinery) will be described.
FIG. 2 is a cross-sectional view of the pump-integrated expander 29A. As described above, the pump-integrated expander 29A is a fluid machinery in which the expander 23 that generates power by the expansion of the refrigerant is integrally connected to the pump 25 that pumps the refrigerant, and is used by being incorporated into the Rankine cycle 2A.
The pump-integrated expander 29A has a pump unit 50A that configures the pump (piston pump) 25, an expander unit 60A that configures the expander (scroll expander) 23, the rotating shaft 28 that has a function as a drive shaft of the pump unit 50A and a function as an output shaft of the expander unit 60A, and a housing 70 that houses these elements. In addition, the pump-integrated expander 29A is provided with the electromagnetic clutch 31 and the pulley 32 that configure the transmission mechanism 3.
The rotating shaft 28 extends in an axial direction (horizontal direction in the drawings) of the housing 70, and has a crank section 28 a, an axis of which is shifted (offset) from a rotational center of the rotating shaft 28, and a large-diameter end section 28 b.
In addition, bearings 71 a and 71 b that rotatably support the rotating shaft 28 are disposed within the housing 70. The bearing 71 a is disposed in a cylindrical section 70 a formed to project from the one end side (here, a left end side) of the housing 70 to rotatably support the vicinity of an end portion opposite to the large-diameter end section 28 b of the rotating shaft 28. The bearing 71 b is disposed in a substantially center in the axial direction of the housing 70 to rotatably support the large-diameter section 28 b of the rotating shaft 28.
The crank section 28 a of the rotating shaft 28 is housed in a crank chamber 72A formed in the housing 70. Furthermore, in the cylindrical section 70 a of the housing 70 at a position on the crank chamber 72A side from the bearing 71 a, a shaft seal 73 that seals a space between an outer peripheral surface of the rotating shaft 28 and an inner peripheral surface of the cylindrical section 70 a is provided.
An armature plate 81 is attached to the end portion (leading end portion) of the rotating shaft 28 protruding outward from the cylindrical section 70 a, and the pulley 32 is rotatably attached to the outer peripheral surface of the cylindrical section 70 a via a bearing 82. Also, a clutch coil 83 is housed in an annular groove 32 a formed on the end surface of the pulley 32. The electromagnetic clutch 31 includes the armature plate 81 and the clutch coil 83, the armature plate 81 is magnetically attracted to the end surface of the pulley 32 by energizing the clutch coil 83, and the electromagnetic clutch 31 is engaged.
Next, the pump unit 50A will be described.
The pump unit 50A includes a piston 51 housed in a pump cylinder 74A formed to communicate with the crank chamber 72A, and a connecting rod 52 which is connected to the piston 51 at one end and connected to the crank section 28 a of the rotating shaft 28 at the other end to convert rotational motion of the rotating shaft 28 into reciprocating linear motion of the piston 51.
An open end of the pump cylinder 74A is covered by a cylinder cover 75. The cylinder cover 75 is formed with a suction port 75 a that intakes the refrigerant (liquid-phase refrigerant) liquefied in the condenser 24 into the pump cylinder 74A, and a discharge port 75 b that discharges the drawn refrigerant. The suction port 75 a is provided with a check valve 76 a that only allows the intake of refrigerant, and the discharge port 75 b is provided with a check valve 76 b that only allows the discharge of the refrigerant.
The pump unit 50A repeats the intake and the discharge of the refrigerant (liquid-phase refrigerant) by reciprocating motion of the piston 51 within the pump cylinder 74A along with the rotation of the rotating shaft 28, thereby pumping the refrigerant.
Next, the expander unit 60A will be described.
The expander unit 60A includes a fixed scroll 61 fixed to an end portion (right end portion in the drawings) on the opposite side of the cylindrical section 70 a of the housing 70, and an orbiting scroll 62.
The fixed scroll 61 has a disk-shaped base portion 61 a, and a spiral wrap 61 b uprightly provided on one surface (left side in the drawings) of the base portion 61 a. An introduction port 61 c of the refrigerant is formed to penetrate through a substantially central portion of the base portion 61 a of the fixed scroll 61. Also, the orbiting scroll 62 has a substantially disk-shaped base portion 62 a, and a spiral wrap 62 b uprightly provided on the surface of the base portion 62 a on the fixed scroll 61 side.
The fixed scroll 61 and the orbiting scroll 62 are disposed so that the spiral wraps 61 b and 62 b are engaged with each other, and an expansion chamber 63 that expands the introduced refrigerant (gas-phase refrigerant) is formed between both wraps 61 b and 62 b. Furthermore, between a surface of the base portion 62 a of the orbiting scroll 62 on the opposite side to the fixed scroll 61 and a surface of the housing 70 facing thereto, an anti-rotation member 77 such as a ball coupling that prevents the rotation of the orbiting scroll 62 is disposed.
In the expander unit 60A, when the refrigerant (gas-phase refrigerant) introduced into the expansion chamber 63 via the introduction port 61 c is expanded within the expansion chamber 63, the orbiting scroll 62 performs orbiting motion with respect to the fixed scroll 61. The expansion chamber 63 moves to the peripheral portion from the central portion, while increasing the volume along with the orbiting motion of the orbiting scroll 62, and the refrigerant (gas-phase refrigerant) after expansion is discharged to a refrigerant outlet chamber 78A of the housing 70. The refrigerant outlet chamber 78A is, for example, a space formed on the radially outer side of the orbiting scroll 62 in the housing 70.
In the housing 70, the pump unit 50A and the expander unit 60A are connected to each other via a driven crank mechanism 80. Specifically, the large-diameter section 28 b of the rotating shaft 28 is connected to the orbiting scroll 62 via the driven crank mechanism 80.
The driven crank mechanism 80 has a flange section 81 fixed to the end surface of the large-diameter section 28 b of the rotating shaft 28, a crank pin 82 which is uprightly provided at a position shifted from the rotation center of the rotating shaft 28 of the end surface of the flange section 81 and which is parallel to the rotating shaft 28, and an eccentric bush 83 provided on the orbiting scroll 62 side. The eccentric bush 83 is disposed in a hollow boss section 62 c formed on the surface of the base portion 62 a of the orbiting scroll 62 on the opposite side to the fixed scroll 61 via a bearing 84.
The crank pin 82 is inserted into an insertion hole 83 a formed in the eccentric bush 83. The insertion hole 83 a is formed at a position shifted from the center of the bush, and the eccentric bush 83 is configured to oscillate with respect to the crank pin 82. Thus, in the driven crank mechanism 80, the orbiting motion of the crank pin 82 becomes orbiting motion of the eccentric bush 83 as it is, and conversely, the orbiting motion of the eccentric bush 83 becomes orbiting motion of the crank pin 82 as it is.
By the driven crank mechanism 80, the rotational motion of the rotating shaft 28 is converted into the orbiting motion of the orbiting scroll 62, or the orbiting motion of the orbiting scroll 62 is converted into the rotational motion of the rotating shaft 28. Moreover, as described above, the pump unit 50 is driven by the rotation of the rotating shaft 28 to pump the liquid-phase refrigerant.
Since the balance between the eccentric bush 83 and the orbiting scroll 62 is kept to reduce an occurrence of vibration or the like in the expander unit 60A, a counterweight (balance weight) 85 is fixed to the eccentric bush 83. In addition, an oscillating range of the eccentric bush 83 with respect to the crank pin 82 is regulated by engagement between a regulating hole 81 a provided in the flange section 81 and a regulating projection 83 b provided in the eccentric bush 83.
Here, in the housing 70, the crank chamber 72A on the pump unit 50A side and the refrigerant outlet chamber 78A on the expander unit 60A side are in communication with each other via the bearing 71 b that supports the large-diameter section 28 b of the rotating shaft 28, a housing space of the driven crank mechanism 80, and the anti-rotation member 77, in other words, via a gap space between the pump unit 50A and the expander unit 60A in the housing 70. In addition, an outlet port 79A through which the refrigerant after expansion discharged to the refrigerant outlet chamber 78A from the expander unit 60A flows out to the condenser 24 is open to the crank chamber 72A.
It is preferable that the outlet port 79A be formed to open to the bottom (a lower portion in the vertical direction of the pump-integrated expander 29A) of the crank chamber 72A.
Thus, in the pump-integrated expander 29A, as illustrated by arrows in FIG. 3, the gas-phase refrigerant (of high temperature after expansion), which has been discharged to the refrigerant outlet chamber 78A from the expander unit 60A, enters the crank chamber 72A via the anti-rotation member 77, the housing space of the driven crank mechanism 80, and the bearing 71 b, and then, flows out of the outlet port 79A that is open to the crank chamber 72A (that is, flows out through the crank chamber 72). The gas-phase refrigerant, which has flowed out of the outlet port 79A, is liquefied by the condenser 24, and then is pumped by the pump unit 50A.
According to the above-described pump-integrated expander 29A (fluid machinery), since the refrigerant outlet chamber 78A through which the gas-phase refrigerant after expansion is discharged from the expander unit 60A (expander) is in communication with the crank chamber 72A of the pump unit 50A (piston pump), the interior of the crank chamber 72A can be set to a state in which the liquid-phase refrigerant is easily gasified, and it is possible to reduce the amount of the liquid-phase refrigerant that flows into the crank chamber 72A and/or is stored in the crank chamber 72A. Thus, in particular, a decrease in lubrication performance of the mechanical sliding section in the crank chamber 72A of the pump unit 50A and an increase in stirring resistance of the liquid-phase refrigerant due to the rotating shaft 28 (crank section 28 b) can be reduced, durability of the mechanical sliding section can be improved, and the mechanical loss can be small.
Furthermore, since the outlet port 79A is open to the bottom (lower portion) of the crank chamber 72A, even if the liquid-phase refrigerant flows into the crank chamber 72A, the flowed-in liquid-phase refrigerant can be discharged from the outlet port 79A, and thus, the storage of the refrigerant in the crank chamber 72A can be reduced.
Furthermore, since the gas-phase refrigerant after expansion of the relatively high temperature flows to the outside (the condenser 24 side) through the crank chamber 72A, even when the liquid-phase refrigerant is stored in the crank chamber 72A, it is possible to cause the liquid-phase refrigerant to flow (discharge) out of the outlet port 79A as a gas-phase refrigerant, by gasifying the majority of the liquid-phase refrigerant. This makes it possible to further reduce a decrease in the lubrication performance of the mechanical sliding section of the pump unit 50A and an increase in the stirring resistance of the liquid-phase refrigerant due to the rotating shaft 28.
In addition, by allowing the crank chamber 72A and the refrigerant outlet chamber 78A to communicate with each other via the bearing 71 b that rotatably supports the rotating shaft 28 and via the anti-rotation member 77 that prevents rotation of the orbiting scroll 62, there is no need to form, in the housing 70, a new dedicated communication passage or the like for allowing the crank chamber 72A and the refrigerant outlet chamber 78A to communicate with each other. This makes it possible to reduce an increase in size of the pump-integrated expander 29A and an increase in production cost.
Incidentally, the pump-integrated expander 29A is configured so that the outlet port 79A through which the refrigerant after expansion flows toward the condenser 24 is open to the crank chamber 72A and the gas-phase refrigerant after expansion discharged from the expander 60 flows to the outside (the condenser 24 side) via the crank chamber 72A. However, the crank chamber 72A and the refrigerant outlet chamber 78A may have any configuration that enables communication with each other, and the position at which the outlet port 79A is formed is not limited to the configuration according to the above-described embodiment.
For example, as illustrated in FIG. 4A, the outlet port 79A may be open to the refrigerant outlet chamber 78A. In addition, as illustrated in FIG. 4B, a communication passage 91 through which the crank chamber 72A and the space on the expander unit 60A side such as the housing space of the driven crank mechanism 80 are in communication with each other may be formed in the housing 70. Also in this case, since the crank chamber 72A can be set to a state in which the liquid-phase refrigerant is easily gasified, it is possible to reduce an amount of liquid-phase refrigerant that flows into the crank chamber 72A and/or is stored in the crank chamber 72A.
Furthermore, in a case in which the outlet port 79A is open to the refrigerant outlet chamber 78A, the refrigerant gasified in the crank chamber 72A is supplied to the refrigerant outlet chamber 78A via the bearing 71 b, the housing space of the anti-rotation member 77, and the anti-rotation member 77, and flows to the outside (condenser 24 side) from the outlet port 79A along with the gas-phase refrigerant after expansion, as illustrated by arrows in FIG. 4A.
Furthermore, when the communication passage 91 through which the crank chamber 72A communicates with the space on the expander unit 60A side such as the housing space of the driven crank mechanism 80 is formed in the housing 70, the refrigerant after expansion, which has passed through the anti-rotation member 77 and the housing space of the driven crank mechanism 80, enters the crank chamber 72A via the bearing 71 b and the communication passage 91, and then flows out of the outlet port 79A that is open to the crank chamber 72A, as illustrated in FIG. 4B.
Furthermore, a communication passage through which the crank chamber 72A and the refrigerant outlet chamber 78A directly communicate with each other may be formed in the housing 70, and a communication passage through which the outlet port 79A and the refrigerant outlet chamber 78A in the configuration illustrated in FIGS. 2 and 3 communicate with each other may be formed in the housing 70. Furthermore, these communication passages may be provided outside the housing 70. Also in this case, since the interior of the crank chamber 72A can be set to a state in which the liquid-phase refrigerant is easily gasified, it is possible to reduce an amount of liquid-phase refrigerant that flows into the crank chamber 72A and/or is stored in the crank chamber 72A.
Next, a second embodiment of the present invention will be described. FIG. 5 illustrates a schematic configuration of an exhaust heat recovery apparatus 1B in the second embodiment to which the fluid machinery according to the present invention is applied.
The exhaust heat recovery apparatus 1A of the first embodiment drives the pump 25 that circulates the refrigerant of the Rankine cycle 2A by the driving force generated by the expander 23, and assists the output of the engine 10. Moreover, the pump-integrated expander 29A is incorporated into the Rankine cycle 2A.
In contrast, the exhaust heat recovery apparatus 1B of the second embodiment has a generator motor 100 and converts exhaust heat of an engine 10 into electrical energy to use it, by driving the generator motor 100 by the driving force generated by an expander 23. Moreover, an expander-pump-generator motor-integrated fluid machinery 29B is incorporated into a Rankine cycle 2B. In addition, in the present embodiment, the transmission mechanism 3 in the first embodiment is not provided, and a pump 25 is driven by the generator motor 100. Also, in FIG. 5, the same elements as those of FIG. 1 are denoted by the same reference numbers, and the functions thereof are the same.
In FIG. 5, the exhaust heat recovery apparatus 1B includes the Rankine cycle 2B, the generator motor 100, and a control unit 4B.
In a refrigerant circulation passage 21 of the Rankine cycle 2B, a heater 22, the expander 23, a condenser 24, and the pump 25 are disposed in this order. Furthermore, a bypass passage 26 that circulates the refrigerant while bypassing the expander 23 is provided between the heater 22 and the condenser 24, and in the bypass passage 26, a bypass valve 27 that opens and closes the bypass passage 26 is provided.
The generator motor 100 is connected to a power storage apparatus 102 via a power converter 101 (such as a rectifier and an inverter). The generator motor 100 is disposed between the expander 23 and the pump 25, is driven by the power supplied from the power storage apparatus 102, or is driven by the driving force generated by the expander 23.
The control unit 4B controls the operation of the bypass valve 27 and controls power supply and/or stop of power supply to the generator motor 100 from the power storage apparatus 102. When power is supplied to the generator motor 100 from the power storage apparatus 102, the generator motor 100 is operated as a motor to drive the pump 25. Meanwhile, when the power supply to the generator motor 100 from the power storage apparatus 102 is stopped, the generator motor 100 is operated as a generator, and is driven by the driving force generated by the expander 23 to generate power.
When the Rankine cycle 2B is started up, the control unit 4B opens the bypass valve 27 and supplies the power to the generator motor 100 from the power storage apparatus 102 to operate the generator motor 100 as a motor, thereby driving the pump 25. Thus, the refrigerant is circulated while bypassing the expander 23. Moreover, for example, when the pressure difference before and after the expander 23 becomes equal to or greater than a predetermined value, the control unit 4B closes the bypass valve 27 and causes the refrigerant to circulate via the expander 23. Thereafter, when the expander 23 generates sufficient driving force, the control unit 4B stops the power supply to the generator motor 100 from the power storage apparatus 102, to operate the generator motor 100 as a generator. Thus, the driving force generated by the expander 23 drives the pump 25 and drives the generator motor 100, and thus, the generator motor 100 generates electric power. The electric power generated by the generator motor 100 is supplied to the power storage apparatus 102 via the power converter 101.
In this embodiment, the expander 23, the pump (piston pump) 25, and the generator motor 100 are integrally connected and configured as a fluid machinery 29B having a common rotating shaft 105. That is, the rotating shaft 105 of the fluid machinery 29B has a function as an output shaft of the expander 23, a function as a drive shaft of the pump 25, and a function as a drive shaft of the generator motor 100.
Next, the configuration of the fluid machinery 29B in which the expander 23, the pump (piston pump) 25, and the generator motor 100 are integrally connected will be described.
FIG. 6 is a cross-sectional view of the fluid machinery 29B.
As illustrated in FIG. 6, the fluid machinery 29B has a pump unit 50B that configures the pump (piston pump) 25, a generator motor unit 110 that configures the generator motor 100, an expander unit 60B that configures the expander (scroll expander) 23, the rotating shaft 105 that has a function as a drive shaft of the pump unit 50B, a function as a drive shaft of the generator motor unit 110, and a function as an output shaft of the expander unit 60B, and a housing 120 that houses these elements.
The housing 120 has a first housing 121 that houses the pump unit 50B and the generator motor unit 110, a second housing 122 that houses the expander unit 60B, and a connecting member 123 that connects the first housing 121 and the second housing 122. Specifically, the first housing 121 is fitted and fixed to one side (left side in the drawings) of the connecting member 123, and the second housing 122 is fitted and fixed to the other side (right side in the drawings) of the connecting member 123.
A through hole 123 a is formed in the connecting member 123, and the internal space of the first housing 121 and the internal space of the second housing 122 are in communication with each other by the through hole 123 a.
The rotating shaft 105 extends in the first housing 121 in an axial direction (horizontal direction in the drawings), and has a crank section 105 a having an axial center shifted (offset) from a rotation center of the rotating shaft 105 at one end side thereof (left end side in the drawings). The rotating shaft 105 is rotatably supported by a bearing 131 a disposed in the first housing 121 and a bearing 131 b held by the connecting member 123. Furthermore, the crank section 105 a of the rotating shaft 105 is housed in a crank chamber 72B formed in the first housing 121.
The pump unit 50B includes a piston 51 housed in a pump cylinder 74B that is formed to communicate with the crank chamber 72B, and a connecting rod 52 that is connected to the piston 51 at one end and is connected to the crank section 105 a of the rotating shaft 105 at the other end to convert rotational motion of the rotating shaft 105 into reciprocating linear motion of the piston 51. Furthermore, similar to the first embodiment, an open end of the pump cylinder 74B is covered by a cylinder cover 75 that is formed with a suction port 75 a and a discharge port 75 b. The suction port 75 a and the discharge port 75 b are provided with check valves 76 a and 76 b, respectively.
The pump unit 50B repeats the intake and discharge of the refrigerant (liquid-phase refrigerant) by reciprocating motion of the piston 51 within the pump cylinder 74B along with the rotation of the rotating shaft 105, thereby pumping the refrigerant.
The generator motor unit 110 is disposed in a space (housing space) adjacent to the crank chamber 72B via the bearing 131 a within the first housing 121.
The generator motor unit 110 has a rotor 111 including, for example, a permanent magnet fixed to the rotating shaft 105, and a stator 112 fixed to the inner peripheral surface of the first housing 121 so as to surround the rotor 111.
The stator 112 has a yoke 112 a, and, for example, three sets of coils 112 b wound around the yoke 112 a. The coil 112 b generates a magnetic field that rotates the rotor 111 by being supplied with three-phase alternating current from the power storage apparatus 102 via the power converter 101, whereby the rotating shaft 105 rotates and the pump unit 50B is driven. Furthermore, the coil 112 b generates the three-phase alternating current along with the rotation of the rotor 111, and the generated three-phase alternating current is supplied to the power storage apparatus 102 via the power converter 101. Thus, the power storage apparatus 102 is charged.
Similar to the first embodiment, the expander unit 60B includes a fixed scroll 61, and an orbiting scroll 62. The fixed scroll 61 is fixed within the second housing 122, and the second housing 122 is formed with an introduction hole 122 a for introducing the refrigerant into the second housing 122.
The fixed scroll 61 has a disk-shaped base portion 61 a, and a spiral wrap 61 b uprightly provided on one surface (left surface in the drawings) of the base portion 61 a. An introduction port 61 c of the refrigerant is formed to penetrate through a substantially central portion of the base portion 61 a of the fixed scroll 61. Furthermore, the orbiting scroll 62 has a substantially disk-shaped base portion 62 a, and a spiral wrap 62 b uprightly provided on the surface of the base portion 62 a on the fixed scroll 61 side.
The fixed scroll 61 and the orbiting scroll 62 are disposed so that the spiral wraps 61 b and 62 b are engaged with each other, and an expansion chamber 63 that expands the introduced gas-phase refrigerant is formed between the wraps 61 b and 62 b. In this embodiment, a space 122 b having a relatively large volume is formed on the rear side (opposite side of the orbiting scroll 61 side) of the fixed scroll 61 of the second housing 122, and thus, for example, even when the refrigerant introduced from the introduction hole 122 a contains the liquid-phase refrigerant (that is, a gas-liquid mixed state), introduction of the liquid-phase refrigerant into the introduction port 61 c formed at the base portion 61 a of the fixed scroll 61, and ultimately into the expansion chamber 63 can be suppressed.
Furthermore, between the surface of the base portion 62 a of the orbiting scroll 62 on the opposite side to the fixed scroll 61 and the surface of the connecting member 123 facing thereto, an anti-rotation member 77 such as a ball coupling that prevents rotation of the orbiting scroll 62 is disposed.
In the expander unit 60B, the gas-phase refrigerant is introduced into the expansion chamber 63 via the introduction hole 122 a formed in the second housing 122, the space 122 b on the rear side of the fixed scroll 61, and the introduction port 61 c formed in the base portion 61 a of the fixed scroll 61. Moreover, when the introduced gas-phase refrigerant expands within the expansion chamber 63, the orbiting scroll 62 performs the orbiting motion with respect to the fixed scroll 61. The expansion chamber 63 moves while increasing the volume to the peripheral portion from the central portion along with the orbiting motion of the orbiting scroll 62, and the refrigerant after expansion (gas-phase refrigerant) is discharged to a refrigerant outlet chamber 78B in the second housing 122. The refrigerant outlet chamber 78B is, for example, a space formed on the radially outer side of the orbiting scroll 62 in the second housing 122.
Furthermore, the rotating shaft 105 extending in the first housing 121 in the axial direction is connected to the orbiting scroll 62 via a driven crank mechanism 80.
Similar to the first embodiment, the driven crank mechanism 80 includes a flange section 81 fixed to the end surface of the rotating shaft 105, a crank pin 82 which is uprightly provided at a position shifted from the rotation center of the rotating shaft 28 of the end surface of the flange section 81 and which is parallel to the rotating shaft 28, and an eccentric bush 83 provided on the orbiting scroll 62 side.
The eccentric bush 83 is disposed in a hollow boss section 62 c formed on the surface of the base portion 62 a of the orbiting scroll 62 on the opposite side to the fixed scroll 61 via a bearing 84. The crank pin 82 is inserted into the insertion hole 83 a formed in the eccentric bush 83. The insertion hole 83 a is formed at a position shifted from the center of the bush, and the eccentric bush 83 is configured to oscillate with respect to the crank pin 82.
Furthermore, in order to keep a balance between the eccentric bush 83 and the orbiting scroll 62 to reduce an occurrence of vibration or the like in the expander unit 60B, a counterweight (balance weight) 85 is fixed to the eccentric bush 83. In addition, an oscillating range of the eccentric bush 83 with respect to the crank pin 82 is regulated by engagement between a regulating hole 81 a provided in the flange section 81 and a regulating projection 83 b provided in the eccentric bush 83.
By the driven crank mechanism 80, the rotational motion of the rotating shaft 105 is converted into the orbiting motion of the orbiting scroll 62, or the orbiting motion of the orbiting scroll 62 is converted into the rotational motion of the rotating shaft 105. Furthermore, as described above, the pump unit 50B is driven by the rotation of the rotating shaft 105 to pump the liquid-phase refrigerant, the generator motor unit 110 is driven to generate electric power, and the power storage apparatus 102 is charged.
Here, in the housing 120, the crank chamber 72B on the pump unit 50B side and the refrigerant outlet chamber 78B on the expander unit 60B side are in communication with each other, via the bearing 131 b that supports the rotating shaft 105, the generator motor unit 110 (especially, a gap space between the rotor 111 and the stator 112), the through hole 123 a formed in the connecting member 123, and the anti-rotation member 77.
In addition, an outlet port 79B that causes the refrigerant after expansion to flow toward the condenser 24 is open to the crank chamber 72B. It is preferable that the outlet port 79B be formed to open to the bottom (lower portion in the vertical direction of the fluid machinery 29B) of the crank chamber 72B.
Thus, in the fluid machinery 29B according to this embodiment, as illustrated by arrows in FIG. 7, the gas-phase refrigerant (after expansion), which has been discharged to the refrigerant outlet chamber 78B from the expander unit 60B, enters the crank chamber 72B via the anti-rotation member 77, the through hole 123 a formed in the connecting member 123, the generator motor unit 110 (the gap space between the rotor 111 and the stator 112), and the bearings 131 a, and then flows out of the outlet port 79B that is open to the crank chamber 72B. Moreover, the gas-phase refrigerant, which has flowed out of the outlet port 79B, is liquefied by the condenser 24, and then is pumped by the pump unit 50B.
Also in the fluid machinery 29B according to the second embodiment, since the refrigerant outlet chamber 78B through which the refrigerant (gas-phase refrigerant) after expansion is discharged from the expander unit 60B (expander) is in communication with the crank chamber 72B of the pump unit 50B (piston pump), it is possible to obtain the same effects as that of the fluid machinery (pump-integrated expander 29A) according to the first embodiment.
That is, since the interior of the crank chamber 72B can be set to a state in which the liquid-phase refrigerant is easily gasified, it is possible to reduce the amount of liquid-phase refrigerant that flows into the crank chamber 72B and/or is stored in the crank chamber 72B. Furthermore, even if the liquid-phase refrigerant flows into the crank chamber 72B, the flowed-in liquid-phase refrigerant can be discharged from the outlet port 79B, and thus, the storage of the refrigerant in the crank chamber 72B can be reduced. Furthermore, since the gas-phase refrigerant after expansion of relatively high temperature flows to the outside through the crank chamber 72B, even when the liquid-phase refrigerant is stored in the crank chamber 72B, it is possible to cause the liquid-phase refrigerant to flow (discharge) out of outlet port 79B as the gas-phase refrigerant, by gasifying the majority of the liquid-phase refrigerant.
In the fluid machinery 29B of the above-described embodiment, the outlet port 79B through which the refrigerant after expansion flows out toward the condenser 24 is open to the crank chamber 72B, but is not limited thereto. The crank chamber 72B and the refrigerant outlet chamber 78B may have any configuration that enables communication with each other, and for example, as illustrated in FIG. 8, the outlet port 79B may be open to the housing space of the generator motor unit 110 of the first housing 121. Furthermore, the outlet port 79B may be open to the refrigerant outlet chamber 72B, or a communication passage through which the housing space of the generator motor 90 communicates with the crank chamber 72B may be formed in the first housing 121.
Furthermore, a communication passage through which the crank chamber 72B and the refrigerant outlet chamber 78B directly communicate with each other may be formed in the housing 120 (the first housing 121, the second housing 122, and the connecting member 123), or a communication passage through which the outlet port 79B and the refrigerant outlet chamber 78B in the configuration illustrated in FIG. 6 communicate with each other may be formed in the housing 120. Furthermore, these communication passages may be provided outside the housing 120. Also in this case, since the interior of the crank chamber 72B can be set to a state in which the liquid-phase refrigerant is easily gasified, it is possible to reduce the amount of liquid-phase refrigerant that flows into the crank chamber 72A and/or is stored in the crank chamber 72B.
Moreover, in the fluid machinery 29B of the above-described embodiment, the expander 23, the pump (piston pump) 25, and the generator motor 100 are integrally connected, but the generator motor 100 may be used as a generator. In this case, it is preferable that the exhaust heat recovery apparatus 1B have a transmission mechanism 3 similar to the exhaust heat recovery apparatus 1A according to the first embodiment, and be configured to be able to drive the pump 25 by the engine 10.
The fluid machinery has been described above which is applied to the Rankine cycle and has the expander that generates power by expanding the gas-phase refrigerant and the piston pump that pumps the liquid-phase refrigerant. However, it is also possible to apply the technical concept of the present invention to a case in which the expander and the piston pump are separately provided. In this case, in the Rankine cycle, a communication passage through which the crank chamber of the piston pump that pumps the liquid-phase refrigerant communicates with a portion that is on the outlet side of the expander, for example, the communication passage through which the crank chamber of the piston pump communicates with the refrigerant flow passage leading to the condenser from the expander may be provided.

REFERENCE SYMBOL LIST

1A, 1B Exhaust heat recovery apparatus
2A, 2B Rankine cycle
10 Engine
21 Refrigerant circulating passage
22 Heater
23 Expander
24 Condenser
25 Pump (piston pump)
28 Rotating shaft
29A Pump-integrated expander (fluid machinery)
29B Expander-pump-generator motor-integrated fluid machinery
50A, 50B Pump unit
51 Piston
52 Connecting rod
60A, 60B Expander unit
61 Fixed scroll
62 Orbiting scroll
71 a, 71 b Bearing (bearing section)
70 Housing
72A, 72B Crank chamber
77 Anti-rotation member
78A, 78B Refrigerant outlet chamber
79A, 79B Outlet port
80 Driven crank mechanism
91 Communication passage
100 Generator motor
105 Rotating shaft
110 Generator motor unit
111 Rotor
112 Stator
120 Housing

Claims

1. A fluid machinery comprising:

an expander that generates power by expansion of a refrigerant; and

a piston pump that pumps the refrigerant,

wherein a refrigerant outlet chamber through which the refrigerant after expansion is discharged from the expander communicates with a crank chamber of the piston pump.

2. The fluid machinery according to claim 1,

wherein the refrigerant outlet chamber and the crank chamber communicate with each other within a housing that houses the expander and the piston pump.

3. The fluid machinery according to claim 2,

wherein the refrigerant after expansion, which has been discharged to the refrigerant outlet chamber from the expander, is discharged to the outside of the housing through the crank chamber.

4. The fluid machinery according to claim 2,

wherein the refrigerant outlet chamber and the crank chamber communicate with each other via a bearing section that rotatably supports a rotating shaft having a function as an output shaft of the expander and a function as a drive shaft of the piston pump.

5. The fluid machinery according to claim 4,

wherein the expander is a scroll expander,

the refrigerant outlet chamber and the crank chamber communicate with each other via the bearing section and an anti-rotation member that prevents rotation of an orbiting scroll in the scroll expander.

6. The fluid machinery according to claim 1,

wherein a communication passage through which the refrigerant outlet chamber and the crank chamber communicate with each other is provided.

7. The fluid machinery according to claim 1,

wherein a generator motor is provided between the expander and the piston pump.

8. The fluid machinery according to claim 7,

wherein the refrigerant outlet chamber and the crank chamber communicate with each other via the generator motor.