Fluid machine for Rankine cycle

• US 20070175212A1
• Filed: 12/18/2006
• Published: 08/02/2007
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Original Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Inventors: Uno, Keiichi, Kishita, Hiroshi, Inaba, Atsushi, Kawase, Yasuhiro, Takeuchi, Yasuhiro, Asa, Hironori, Ogawa, Hiroshi, Uchida, Kazuhide
• Granted Patent: US 7,870,733 B2
• Time in Patent Office: Days
• US Class Current: 60/519
• CPC Class Codes: F01C 1/0215 where only one member is moving
• CPC Class Codes: F01C 13/04 for driving pumps or compressors
• CPC Class Codes: F01K 21/005 using mixtures of liquid and steam or evaporation of a liquid by expansion
• CPC Class Codes: F01K 25/04 the fluid being in different phases, e.g. foamed
• CPC Class Codes: F01K 25/06 using mixtures of different fluids plants using mixtures of steam and gas F01K21/04
• CPC Class Codes: F04C 2240/45 Hybrid prime mover

Abstract

It is an object to provide a fluid machine, which is simple in structure and in which lubricating oil containing smaller amount of the working fluid is supplied to sliding portions of an expansion device. The fluid machine has the expansion device for generating a driving force by expansion of the working fluid, which contains the lubricating oil and is heated to a gas phase condition. The fluid machine further has an electric power generating device driven by the driving force of the expansion device and generating electric power. An oil pooling portion is formed in a fluid passage, through which the working fluid discharged from the expansion device flows, such that the lubricating oil contained in the working fluid is brought into contact with at least one of sliding portions of the expansion device and the electric power generating device. And a heating unit is provided to heat the working fluid in the oil pooling portion.

Claims

1. A fluid machine comprising:

an expansion device for generating a driving force by expansion of working fluid, which includes lubricating oil and is heated to become gas-phase condition;

an electric power generator driven by the driving force of the expansion device and for generating electric power;

an oil pooling portion provided in a passage, through which the working fluid discharged from the expansion device flows, for pooling the lubricating oil contained in the working fluid such that the lubricating oil is in contact with at least one of sliding portions of the expansion device and the electric power generator; and

a heating unit for heating the working fluid in the oil pooling portion.

2. A fluid machine according to claim 1, wherein

the heating unit is operated at starting up the expansion device.

3. A fluid machine according to claim 1, wherein

the heating unit is operated during a normal operation of the expansion device.

4. A fluid machine according to claim 1, wherein

the heating unit is operated when viscosity of the lubricating oil or any physical quantity related to the viscosity is lower than a predetermined value.

5. A fluid machine according to claim 1, wherein

the heating unit comprises a stator of the electric power generator, wherein the stator generates the heat when electric current is supplied to the stator in such a manner that a power factor is decreased.

6. A fluid machine according to claim 1, wherein

the heating unit comprises a fluid passage, through which heat medium flows from an external high temperature source.

7. A fluid machine according to claim 1, wherein

the heating unit comprises an electric heating device.

8. A fluid machine comprising:

an expansion device for generating a driving force by expansion of working fluid, which includes lubricating oil and is heated to become gas-phase condition;

an electric power generator operated with the expansion device; and

a housing for accommodating the expansion device and the electric power generator,

wherein the fluid machine further comprises;

an oil separating portion for separating the lubricating oil contained in the working fluid discharged from the expansion device;

an oil pooling portion provided in the housing for pooling the lubricating oil separated from the working fluid;

a heating unit for heating the lubricating oil; and

an oil supply portion for supplying the lubricating oil pooled in the oil pooling portion to sliding portions of the expansion device.

9. A fluid machine according to claim 8, wherein

the electric power generator is arranged at an upper side of the expansion device,

a fluid passage is provided in the housing for introducing the working fluid discharged from the expansion device to an upper portion of the housing,

the oil separating portion is so structured that the lubricating oil is separated from the working fluid in accordance with decrease of flow speed of the working fluid, when the working fluid flows from the fluid passage into an inside of the housing,

the oil pooling portion is formed at an upper side of the expansion device,

the heating unit comprises a high temperature portion, the temperature of which is higher than that of the working fluid discharged from the expansion device, and

the oil supply portion comprises an oil passage for supplying the lubricating oil from the oil pooling portion to the sliding portions of the expansion device.

10. A fluid machine according to claim 9, wherein

the high temperature portion corresponds to a high temperature area of the expansion device.

11. A fluid machine according to claim 9, wherein

a partitioning portion, which partitions the oil pooling portion and the motor generator, is formed as a thin-walled portion than the other portions.

12. A fluid machine according to claim 8, wherein

the oil pooling portion is arranged at a lower side of the motor generator.

13. A fluid machine according to claim 12, wherein

the working fluid discharged from the expansion device flows to the oil pooling portion, through the inside of the motor generator or through a portion adjacent to an inverter, which controls an operation of the motor generator.

14. A fluid machine according to claim 9, wherein

a pump device is integrally provided to the expansion device at a discharge side of the working fluid, for circulating the working fluid, and

the lubricating oil of the oil pooling portion is sucked by a pressure difference between the expansion device and the pump device, so that the lubricating oil is supplied to the sliding portions through the oil passage.

15. A fluid machine according to claim 14, wherein

the lubricating oil supplied to the sliding portions is further supplied to sliding portions of the pump device.

16. A fluid machine according to claim 8, wherein

fins are provided at the oil pooling portion to increase contact area with the lubricating oil.

17. A fluid machine according to claim 8, wherein

the oil separating portion is provided between the discharge side of the expansion device for the working fluid and the oil pooling portion to separate the lubricating oil from the working fluid.

18. A fluid machine according to claim 8, wherein

a pump device is provided to the expansion device at a discharge side of the working fluid for circulating the working fluid,

the motor generator is arranged at a lower side of the expansion device,

the pump device is arranged at a lower side of the motor generator, and

the oil pooling portion is arranged at a lower side of the pump device,

wherein the fluid machine further comprises;

a fluid passage provided for supplying the working fluid discharged from the expansion device to the oil pooling portion,

an oil passage for communicating the oil pooling portion with the fluid passage through the pump sliding portions of the pump device and the sliding portions for the expansion device, and

an oil pump for supplying the lubricating oil from the oil pooling portion to the pump sliding portions and the sliding portions for the expansion device,

the oil separating portion is provided in the fluid passage at a downstream side of an interfluent point, at which the oil passage interflows into the fluid passage, and

the oil supply portion is composed of the oil passage and the oil pump, and

the heating unit comprises the working fluid, which is discharged from the expansion device and located at the interfluent point of the oil passage.

19. A fluid machine according to claim 18, wherein

the fluid passage is formed such that a part of the fluid passage is formed within the inside space of the housing for the motor generator and the remaining part thereof is formed at an outside of the housing and communicated with the oil pooling portion, and

the oil passage is communicated with inside space of the housing through the sliding portions for the expansion device.

20. A fluid machine according to claim 18, wherein

the expansion device, the motor generator, and the pump device are connected with one another by one single shaft, and

a part of the oil passage is formed in the shaft.

21. A fluid machine according to claim 19, wherein

an oil seal is provided between the motor generator and the pump device in order to block a leakage of the lubricating oil from a side of the motor generator to a side of the pump device.

22. A fluid machine comprising:

a flat and annular cylinder for forming a cylinder chamber;

a ring shaped piston accommodated in the cylinder chamber;

a driving shaft inserted into a center portion of the ring shaped piston and driven by an external driving source; and

bearings for rotatably supporting the driving shaft,

wherein the ring shaped piston is operated within the cylinder chamber by rotation of the driving shaft, so that working fluid sucked into the cylinder chamber is pressurized and pumped out,

an oil storing chamber is so formed around the driving shaft as to cover contacting portions of the driving shaft, which are in contact with the ring shaped piston and the bearings, the oil storing chamber being filled with lubricating oil having a higher viscosity than the working fluid, and

a small space is formed at an axial side surface of the ring shaped piston and at an outer side of the oil storing chamber, the small space being held at a pressure lower than that of the oil storing chamber.

23. A fluid machine according to claim 22, wherein

the small space comprises a groove formed at the axial side surface.

24. A fluid machine according to claim 22, further comprises:

end surface portions arranged to be close to and opposed to the axial side surface to seal an end of the cylinder chamber,

wherein the small space comprises a groove formed at the end surface portions.

25. A fluid machine according to claim 22, wherein

the small space is formed into a circular form at the axial side surface.

26. A fluid machine according to claim 22, wherein

the small space comprises a first space and a second space, which are respectively formed at both axial side surfaces of the ring shaped piston.

27. A fluid machine according to claim 26, wherein

a communication hole is so formed as to penetrate the ring shaped piston in the axial direction, so that the first space and the second space are communicated with each other at a predetermined position.

28. A fluid machine according to claim 22, further comprises:

an inlet port for sucking the working fluid from the outside into the cylinder chamber,

wherein the small space is communicated with the inlet port.

29. A fluid machine according to claim 22, wherein

the lubricating oil is pressurized by an exclusive oil supply pump and supplied to the oil storing chamber.

30. A fluid machine according to claim 29, wherein

the oil supply pump is commonly driven by the external driving source.

31. A fluid machine according to claim 22, wherein

the driving shaft has a crank portion, and

the ring shaped piston is slidably arranged at an outer periphery of the crank portion, so that the ring shaped piston slides on the crank portion and is rotated in accordance with the rotation of the driving shaft with an orbital motion within the cylinder chamber.

32. A fluid machine according to claim 22, wherein

the working fluid is a working fluid circulated in Rankine cycle, which is formed by a heating device, an expansion device, and a condensing device, wherein those components are sequentially connected in a circuit.

33. A fluid machine according to claim 32, wherein

the oil separated from the working fluid at a discharge side of the expansion device is supplied to the oil storing chamber as the lubricating oil through an oil supply passage, which bypasses the condensing device.

34. A fluid machine according to claim 32, wherein

the external driving source comprises an electric motor connected to the expansion device.

35. An expansion device comprises:

a high pressure chamber, into which working fluid heated to a high pressure steam is introduced;

a driven portion driven by expansion of the working fluid of the high pressure steam from the high pressure chamber;

a low pressure portion, from which the working fluid, a pressure of which becomes lower as a result of the expansion, flows out of the expansion device; and

a housing for accommodating the above high pressure chamber, the driven portion, and the low pressure portion,

wherein the expansion device further comprises;

a communication port formed in the housing for bypassing the driven portion and for directly communicating the high pressure chamber with the low pressure portion; and

a switching device for opening and closing the communication port.

36. An expansion device according to claim 35, further comprises:

a partitioning portion provided between the high pressure chamber and the driven portion for partitioning the high pressure chamber and the driven portion from each other,

wherein the communication port is formed in the partitioning portion such that the communication port penetrates the partitioning portion.

37. An expansion device according to claim 35, wherein the switching device comprises;

an electromagnetic valve for opening and closing the communication port in response to an external electrical signal, or a valve body for opening and closing the communication port in association with an electromagnetic valve.

38. An expansion device according to claim 37, wherein

the electromagnetic valve or the valve body closes the communication port when the external electrical signal is supplied thereto, and opens the communication port when the external electrical signal thereto is cut off.

39. An expansion device according to claim 35, further comprising:

an electric power generator provided on a side of the low pressure portion and connected to the driven portion,

wherein the low pressure portion is communicated with the inside of the electric power generator.

40. An expansion device according to claim 35, wherein

the expansion device is provided in Rankine cycle,

a control unit is provided for controlling an operation of the expansion device, and

the control unit opens the switching device when an operation of the Rankine cycle is stopped.

41. An expansion device according to claim 40, wherein

the control unit stops the operation of the expansion device after having opened the switching device.

42. An expansion device according to claim 40, wherein

the control unit opens the switching device when starting up the operation of the Rankine cycle, and closes the switching device after a predetermined time period passes by.