JP2011169257A - Rankine cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stop waste heat recovery by adequately grasping whether or not the pressure of a working fluid for a rankine cycle is abnormal. <P>SOLUTION: A pressure sensor 53 connected with a first flow passage 42 senses the pressure inside the first flow passage 42. A control part 26 controls an inverter 25 based on pressure sensing information obtained from the pressure sensor 53. The control part 26 compares the size of the pressure Px in a set (Nx, Px) of a command rotational frequency Nx and a sensed pressure Px with the pressure Pd in a group of a preset rotational frequency Nx and a pressure Pd (Nx, Pd). In the case of Pd>Px, the control part 26 outputs a stop command to the inverter 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention applies a rotational force to a drive shaft of the rotating electrical machine by utilizing a rotating electrical machine functioning as at least a generator, a rotational speed control means for controlling the rotational speed of the rotating electrical machine, and a Rankine cycle working fluid. The present invention relates to a Rankine cycle device including an expander and a pump that sucks and discharges a Rankine cycle working fluid.

  In this type of Rankine cycle device, when the Rankine cycle working fluid (refrigerant) leaks from the cycle, the Rankine cycle working fluid in the cycle is in a gas-mixed (cavitation) state or all gas state in the upstream region of the pump. Sometimes. In such a state, the flow rate of the Rankine cycle working fluid decreases. If the Rankine cycle is kept operating with the flow rate of the Rankine cycle working fluid lowered, the regenerative power is lowered, or the lubricating oil flowing together with the Rankine cycle working fluid is insufficient, resulting in poor lubrication of the necessary lubrication site. Alternatively, the Rankine cycle working fluid is overheated by heat from a heat exchanger (boiler) that takes heat from the cooling water that cools the heating element (for example, the engine) and transfers it to the Rankine cycle working fluid. When the Rankine cycle working fluid is deteriorated by high temperature, the Rankine cycle working fluid may be deteriorated.

  In the Rankine cycle device (thermal cycle device) disclosed in Patent Document 1, the difference between the upstream pressure and the downstream pressure of the pump that sends the Rankine cycle working fluid to the heat exchanger (boiler) side is a predetermined pressure. In the following cases, the waste heat recovery mode is stopped. If the waste heat recovery mode is stopped, it is possible to avoid the above-described problems caused by a decrease in the flow rate of the Rankine cycle working fluid.

JP 2006-17108 A

  However, even if the difference between the pressure on the upstream side and the pressure on the downstream side of the pump becomes a predetermined pressure or less, the pressure on the downstream side of the pump is not always low. That is, even if the difference becomes equal to or lower than a predetermined pressure, the Rankine cycle working fluid in the cycle is not necessarily in a state of being mixed with gas (cavitation) or completely in a gaseous state. Therefore, the information on the difference between the pressure on the upstream side and the pressure on the downstream side of the pump cannot accurately determine whether or not the Rankine cycle working fluid (refrigerant) is insufficient, and the waste heat recovery efficiency decreases. .

  In order to detect whether or not the Rankine cycle working fluid (refrigerant) is insufficient, it is necessary to detect the pressure on the downstream side of the pump. However, the upper limit of the pressure on the downstream side of the pump, which reflects the situation where the Rankine cycle working fluid (refrigerant) is insufficient, varies depending on the rotational speed. Therefore, it is impossible to accurately determine whether or not the Rankine cycle working fluid (refrigerant) is insufficient only by detecting the pressure on the downstream side of the pump.

  An object of the present invention is to appropriately grasp whether or not the pressure of the working fluid (refrigerant) for Rankine cycle is abnormal so that the recovery of waste heat can be stopped.

  The present invention relates to at least a rotating electrical machine that functions as a generator, an expander that applies a rotational force to a drive shaft of the rotating electrical machine using Rankine cycle working fluid, and an intake and discharge of Rankine cycle working fluid. A Rankine cycle device comprising a pump and rotation control means for controlling the rotation of the drive shaft, wherein the expander and the pump rotate together, is provided downstream of the pump. A pressure detecting means for detecting the pressure in the high pressure flow path upstream of the expander, a rotational speed grasping means for grasping the rotational speed of the drive shaft, and a rotational speed grasped by the rotational speed grasping means; Determining means for determining whether or not a set of the pressure detected by the pressure detecting means is within a preset rotation speed-pressure allowable region, and the rotation control means includes: Force the rotation speed - when in the low pressure area than the pressure tolerance range performs stop control to zero the rotational speed of the rotary electric machine.

  Since it is determined whether or not the set of the detected pressure and the number of revolutions in the high-pressure channel is in the low-pressure region than the preset revolution-pressure allowable region, the Rankine cycle working fluid is insufficient. It is possible to accurately grasp whether or not

In a preferred example, the rotation control means performs the stop control when the pressure in the set is in a higher pressure region than the rotation speed-pressure allowable region.
The pressure in the high-pressure channel may become abnormally high due to clogging of foreign matter. In order to judge whether or not the set of the pressure and the number of rotations in the high-pressure flow path is in a higher pressure region than the preset rotation number-pressure allowable region, the abnormal high pressure of Rankine cycle working fluid is accurately I can grasp it well.

  According to a third aspect of the present invention, a rotating electrical machine that functions as at least a generator, an expander that applies a rotational force to the drive shaft of the rotating electrical machine using the Rankine cycle working fluid, and a Rankine cycle working fluid are sucked in. In the Rankine cycle device in which the expander and the pump rotate integrally with each other, a downstream of the pump and a rotation control means for controlling the rotation of the drive shaft. Pressure detecting means for detecting the pressure in the upstream high-pressure flow path, rotational speed grasping means for grasping the rotational speed of the drive shaft, pressure detected by the pressure detecting means, and grasping by the rotational speed grasping means Determining means for determining whether or not the set with the set number of revolutions is within a preset number of revolutions-pressure permissible region, wherein the rotation control means is configured so that the pressure in the set is Number - when in the high pressure area than the pressure tolerance range performs stop control to zero the rotational speed of the drive shaft.

  In a preferred example, a bypass flow path connecting the downstream side of the expander and the high pressure flow path is provided, and an opening / closing means for opening and closing the bypass flow path is provided. In this control, the opening / closing means is controlled so as to open a path, and then the rotational speed of the drive shaft is made zero.

  If the rotational speed command control means suddenly issues a command to make the rotational speed zero, the rotational speed may increase rapidly. If the bypass flow path is opened before the command for setting the rotational speed to zero is issued, a rapid increase in the rotational speed can be avoided.

In a preferred example, the rotation control means is a rotation speed command control means for commanding and controlling the rotation speed of the rotating electrical machine.
The information on the rotational speed commanded by the rotational speed control means is simple as information for grasping the rotational speed.

  The present invention has an excellent effect that the waste heat recovery can be stopped by properly grasping whether or not the pressure of the Rankine cycle working fluid (refrigerant) is abnormal.

1 is a schematic diagram illustrating a vehicle waste heat recovery apparatus according to a first embodiment. (B) is a sectional side view showing a fluid machine. Rotation speed-pressure graph. The flowchart showing an abnormal pressure countermeasure control program. The rotation speed-pressure graph which shows 2nd Embodiment. The flowchart showing an abnormal pressure countermeasure control program.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1A, the vehicle waste heat recovery apparatus 10 includes an engine 11 and a Rankine cycle circuit 12 as a waste heat source. In the vehicle waste heat recovery device 10 as the Rankine cycle device, a Rankine cycle working fluid (hereinafter referred to as a refrigerant) heated by the waste heat from the engine 11 circulates in the Rankine cycle circuit 12.

  FIG. 1B shows a fluid machine 13 constituting the vehicle waste heat recovery apparatus 10. The housing 14 constituting the fluid machine 13 includes a rotating electrical machine housing 15, a pump housing 16 connected to the rotating electrical machine housing 15, and an expander housing 17 connected to the pump housing 16.

  A drive shaft 18 is rotatably supported by bearings 19 and 20 on the end wall 151 of the rotating electrical machine housing 15 and the pump housing 16, and a rotor 21 is fixed to the drive shaft 18. A stator 22 is fixed to the inner peripheral surface of the rotating electrical machine housing 15 so as to surround the rotor 21. The drive shaft 18, the stator 22 and the rotor 21 constitute a motor / generator 23 as a rotating electrical machine.

  The motor / generator 23 has a function as an electric motor that rotates the rotor 21 by energizing the coil 221 of the stator 22 and a function as a generator that generates electric power in the coil 221 of the stator 22 when the rotor 21 rotates. Have both.

  As shown in FIG. 1A, a battery 24 is electrically connected to the motor / generator 23 via an inverter 25. Electric power generated by the motor / generator 23 is stored in the battery 24 via the inverter 25. A control unit 26 is signal-connected to the inverter 25.

  A pair of side plates 27 and 28 are fixed in the expander housing 17 so as to face each other. A pump chamber 311 is defined between the pump housing 16 and the side plate 27. The drive shaft 18 passes through the pump housing 16 and the side plate 27. A drive gear 29 fixed to the drive shaft 18 and a driven gear 30 meshing with the drive gear 29 are disposed in the pump chamber 311. The pump chamber 311, the drive gear 29 and the driven gear 30 constitute a gear pump 31.

  A cylindrical cylinder block 32 is accommodated between the pair of side plates 27 and 28. In the cylinder block 32, a cylindrical rotor 33 is fixed to the drive shaft 18 on the drive shaft 18, and a vane 34 is provided on the outer peripheral surface of the rotor 33 so as to be able to appear and retract. When the drive shaft 18 rotates, the rotor 33 rotates. As the rotor 33 rotates, the tip of the vane 34 slides on the inner peripheral surface of the cylinder block 32. The outer peripheral surface of the rotor 33, the inner peripheral surface of the cylinder block 32, and the adjacent vane 34 define a working chamber 35 between the pair of side plates 27 and 28.

  A discharge space 36 is defined between the expander housing 17 and the side plate 28, and a discharge port 37 is formed in the expander housing 17 so as to communicate with the discharge space 36. A suction port (not shown) communicating with the working chamber 35 is formed in the expander housing 17.

The side plates 27 and 28, the cylinder block 32, the rotor 33, the vane 34, and the working chamber 35 constitute an expander 38 that outputs mechanical energy by expansion of the refrigerant.
Next, the Rankine cycle circuit 12 in the vehicle waste heat recovery apparatus 10 including the fluid machine 13 will be described.

The Rankine cycle circuit 12 includes an expander 38 and a condenser 39 of the fluid machine 13, a gear pump 31 of the fluid machine 13, a first boiler 40, and a second boiler 41.
The first boiler 40 includes a heat absorber 401 and a heat radiator 402. A heat absorber 401 of the first boiler 40 is connected to the discharge side of the pump chamber 311 (see FIG. 1B) in the gear pump 31 via the first flow path 42. The radiator 402 is provided on the cooling water circulation path 43 connected to the engine 11. A radiator 44 is provided on the cooling water circulation path 43. Cooling water (high temperature fluid) that has cooled the engine 11 of the vehicle circulates in the cooling water circulation path 43. A part of the heat of the cooling water circulating through the cooling water circulation path 43 is transmitted to the heat absorber 401 via the radiator 402 of the first boiler 40. A part of the heat of the cooling water circulating through the cooling water circulation path 43 is radiated by the radiator 44.

  The second boiler 41 includes a heat absorber 411 and a heat radiator 412. A heat absorber 411 of the second boiler 41 is connected to the discharge side of the heat absorber 401 of the first boiler 40 via a connection channel 47. The radiator 412 is provided on an exhaust passage 49 connected to the engine 11. The exhaust from the engine 11 is exhausted from the muffler 50 after radiating heat with the radiator 412.

The refrigerant discharged from the gear pump 31 is heated by heat exchange between the heat absorbers 401 and 411 and the radiators 402 and 412 of the first boiler 40 and the second boiler 41.
A suction port (not shown) in the expander 38 is connected to the discharge side of the heat absorber 411 of the second boiler 41 via a suction flow path 45. The high-temperature and high-pressure refrigerant heated by the first boiler 40 and the second boiler 41 is introduced into the expander 38 through the suction passage 45. The first flow path 42, the heat absorbers 401 and 411, the connection flow path 47, and the suction flow path 45 constitute a high-pressure flow path that is downstream of the gear pump 31 and upstream of the expander 38.

  A condenser 39 is connected to a discharge port 37 (see FIG. 1B) of the expander 38 via a discharge flow path 46. The low-pressure refrigerant expanded by the expander 38 is discharged to the condenser 39 via the discharge flow path 46. A pump chamber 311 (see FIG. 1B) of the gear pump 31 is connected to the discharge side of the condenser 39 via a second flow path 48.

  A bypass channel 51 is connected to the first channel 42. The bypass flow path 51 is connected to the discharge flow path 46 via a direction switching valve 52 that is excited and demagnetized. The direction switching valve 52 includes a normal state in which the suction channel 45 communicates with the condenser 39 via the expander 38 and the discharge channel 46 without passing through the bypass channel 51, and the discharge channel 46 is connected to the bypass channel 51. It is possible to switch from either one of the emergency states communicating with the first flow path 42 via the other 51 to the other. The direction switching valve 52 is in a normal state in a demagnetized state and in an emergency state in an excited state. The direction switching valve 52 is subjected to excitation / demagnetization control by the control unit 26.

  A pressure detector 53 is connected to the first flow path 42. The pressure detector 53 detects the pressure in the first flow path 42. The pressure detection information obtained by the pressure detector 53 as pressure detection means is sent to the control unit 26. The control unit 26 controls excitation and demagnetization of the direction switching valve 52 and the inverter 25 based on the pressure detection information obtained by the pressure detector 53.

Next, the operation of the vehicle waste heat recovery apparatus 10 will be described.
The operation of the vehicle waste heat recovery apparatus 10 is started by operating the motor / generator 23 as an electric motor. The control unit 26 sends a start command to the inverter 25, and the inverter 25 operates the motor / generator 23 as an electric motor based on the start command. The control unit 26 obtains temperature detection information from a temperature detector (not shown) that detects the temperature of the cooling water in the cooling water circulation path 43, and when the detected temperature becomes equal to or higher than a predetermined temperature, the control unit 26 displays the inverter 25. Command to start. When the motor / generator 23 is operated as an electric motor, the drive shaft 18 starts to rotate, and the drive gear 29 of the gear pump 31 and the rotor 33 of the expander 38 start to rotate integrally with the drive shaft 18. The rotation of the drive gear 29 of the gear pump 31 is transmitted to the driven gear 30, and the drive gear 29 and the driven gear 30 rotate in opposite directions while meshing with each other. As a result, the refrigerant in the second flow path 48 passes through the gear pump 31 and is sent to the first flow path 42.

  The refrigerant sent to the first flow path 42 passes through the heat absorber 401 of the first boiler 40, the connection flow path 47, and the heat absorber 411 of the second boiler 41 and is sent to the suction flow path 45. The refrigerant passing through the heat absorber 401 of the first boiler 40 and the heat absorber 411 of the second boiler 41 is heated by waste heat from the engine 11. The high-pressure refrigerant after heating is introduced from the suction port (not shown) into the working chamber 35 of the expander 38 and expands. Due to the expansion of the refrigerant, the expander 38 outputs mechanical energy (rotation imparting force), and the rotor 33 and the drive shaft 18 are rotated by the rotation imparting force. The expander 38 applies a rotational force to the drive shaft 18 of the motor / generator 23 using a refrigerant.

  The refrigerant whose pressure has decreased due to expansion is discharged into the discharge space 36 and then discharged into the discharge flow path 46 through the discharge port 37. The refrigerant discharged to the discharge flow path 46 passes through the condenser 39. As the gear pump 31 is driven by the rotation of the drive shaft 18, the refrigerant discharged from the condenser 39 is introduced into the pump chamber 311 through the second flow path 48 and discharged from the pump chamber 311 to the first flow path 42. The The refrigerant discharged to the first flow path 42 returns to the first boiler 40.

  After the motor / generator 23 starts operating as an electric motor, the mechanical energy (rotation imparting force) output by the expander 38 rotates the drive shaft 18. The control unit 26 controls the motor / generator 23 to function as a generator after the start command, and the motor / generator 23 functions as a generator. Electric power obtained by the motor / generator 23 functioning as a generator is charged to the battery 24 via the inverter 25. The control unit 26 controls the inverter 25 so that the maximum generated power corresponding to the temperature of the cooling water is obtained. That is, the control unit 26 controls the rotation of the motor / generator 23 by instructing the inverter 25 to rotate the motor / generator 23 so that the maximum generated power can be obtained.

  The flowchart of FIG. 3 represents an abnormal pressure countermeasure control program for dealing with the abnormal pressure of the refrigerant. Hereinafter, the abnormal pressure countermeasure control by the control unit 26 will be described based on the flowchart of FIG. 3 and the graph of FIG. 2.

  The direction switching valve 52 is in a demagnetized state, the suction flow path 45 communicates with the condenser 39 via the discharge flow path 46, and the first flow path 42 extends from the discharge flow path 46 via the bypass flow path 51. Communication with is blocked. The control unit 26 detects (understands) the pressure Px in the first flow path 42 at a predetermined sampling interval based on the pressure detection information obtained by the pressure detector 53 (step S1). The control unit 26 determines whether or not the set (Nx, Px) of the command rotational speed Nx commanded to the inverter 25 and the detected pressure Px is within the region Z1 shown in the graph of FIG. 2 (step S2).

  The horizontal axis in the graph of FIG. 2 represents the number of rotations, and the vertical axis represents the pressure. The end line L1 represents the lower limit of the command speed Nx commanded to the inverter 25, and the end line L2 represents the upper limit of the command speed Nx commanded to the inverter 25. A region Zo [region shown by oblique lines] surrounded by the curves K1, K2 and the end lines L1, L2 is a rotation speed-pressure normal region set as a normal region. A region Z1 surrounded by the curves Kd, K1 and the end lines L1, L2 is a rotation speed-pressure allowable region set as an allowable region.

  In the configuration in which the gear pump 31 and the expander 38 rotate integrally (the rotation speed of the gear pump 31 and the rotation speed of the expander 38 are the same), the high pressure of the refrigerant depends on the refrigerant flow rate and the suction flow rate of the expander 38. It is determined within a certain range. The high pressure of the refrigerant is the pressure in the flow path downstream of the gear pump 31 and upstream of the expander 38, and the refrigerant flow rate is determined by the outside air temperature, the pump capacity of the gear pump 31, and the volume efficiency of the gear pump 31. The rotation speed-pressure normal region Zo is set as the predetermined range. If the pressure in the flow path downstream of the gear pump 31 and upstream of the expander 38 falls below the rotational speed-pressure normal range Zo, the refrigerant flow rate decreases and it can be considered that cavitation has occurred.

  When the set (Nx, Px) is within the rotation speed-pressure allowable region Z1 (YES in step S2), the control unit 26 proceeds to step S1. When the set (Nx, Px) is not within the rotation speed-pressure allowable range Z1 (NO in step S2), the control unit 26 determines the pressure Px in the set (Nx, Px) and a preset set (Nx, Pd). ) Is compared with the pressure Pd (step S3). The command rotational speed Nx in the group (Nx, Pd) is the same rotational speed as the command rotational speed Nx in the group (Nx, Px). The group (Nd, Pd) in FIG. 2 is an example on the curve Kd. The pressure Pd is set as a lower limit pressure allowed at the command rotational speed Nd.

  The lower side of the curve Kd shown in FIG. 2 is a low-pressure region having a lower pressure than the rotation speed-pressure allowable region Z1. When the refrigerant pressure in the first flow path 42 is in the low pressure region below the curve Kd, cavitation occurs due to insufficient refrigerant. A curve Kd is an index set to determine whether or not the refrigerant circulating in the Rankine cycle circuit 12 is insufficient.

When pressure Px is equal to or higher than pressure Pd (NO in step S3), control unit 26 proceeds to step S1.
When the pressure Px is less than the pressure Pd (YES in step S3), the control unit 26 instructs the direction switching valve 52 to end processing (step S4).

  The end processing command for the direction switching valve 52 is an excitation command, and the direction switching valve 52 is switched from the demagnetized state to the excited state by this excitation command. When the direction switching valve 52 is excited, the communication from the suction flow path 45 to the condenser 39 via the discharge flow path 46 is blocked, and the discharge flow path 46 is connected to the first flow path via the bypass flow path 51. 42 is communicated. Thereby, the refrigerant discharged from the expander 38 to the discharge flow path 46 goes to the first flow path 42 via the bypass flow path 51.

  When a predetermined time has elapsed from the end processing command for the direction switching valve 52, the control unit 26 outputs a stop command to the inverter 25 (step S5). The stop command for the inverter 25 is a command for setting the rotation speed to zero. As a result, the rotation of the motor / generator 23 is stopped.

  The direction switching valve 52 is an opening / closing means that opens and closes the bypass channel 51. The control unit 26 and the inverter 25 constitute rotation control means for controlling the rotation of the drive shaft 18 and perform stop control. The stop control is control for stopping the rotation of the motor / generator 23 by the control unit 26 outputting a stop command for making the rotational speed of the drive shaft 18 zero to the inverter 25. The control unit 26 is a rotational speed command control unit that commands and controls the rotational speed of the motor / generator 23, and is a rotational speed grasping unit that grasps the rotational speed of the drive shaft 18. The control unit 26 is a determination unit that determines whether or not the set (Nx, Px) is in a preset rotation speed-pressure allowable region.

In the first embodiment, the following effects can be obtained.
(1) The refrigerant is insufficient if the set (Nx, Px) of the command rotational speed Nx and the pressure Px in the first flow path 42 at this time is within the preset rotational speed-pressure allowable range Z1. There is no. If the set (Nx, Px) of the command rotational speed Nx and the pressure Px in the first flow path 42 at this time is in a lower pressure region than the rotational speed-pressure allowable region Z1, the refrigerant is insufficient. The control unit 26 determines whether the set (Nx, Px) of the grasped pressure Px in the first flow path 42 and the command rotational speed Nx is in a lower pressure region than the preset rotational speed-pressure allowable region Z1. Determine whether or not. That is, since it is determined whether or not the pressure Px is too low according to the command rotational speed Nx (the rotational speed of the gear pump 31 and the expander 38), it is possible to accurately grasp whether or not the refrigerant is insufficient. it can.

  (2) When the control unit 26 suddenly issues a command to make the commanded rotational speed zero, the power generation in the motor / generator 23 is stopped, and the rotational resistance suddenly increases with respect to the rotational force applied to the drive shaft 18 by the expander 38. It disappears. Therefore, the rotation of the drive shaft 18 rises rapidly. If it does so, unusual noise will generate | occur | produce and the reliability of the bearings 19 and 20 will be impaired.

  In the present embodiment, since the bypass flow path 51 is opened and then the rotational speed of the drive shaft 18 is controlled to zero, the rotational force applied to the drive shaft 18 by the expander 38 is gradually reduced. go. The stop command for setting the rotational speed to zero is issued after a predetermined time has elapsed from the end processing command. During this predetermined time, the rotation given to the drive shaft 18 by the expander 38 so that the rotation of the drive shaft 18 does not increase. It is set as the time required for the force to be sufficiently reduced. Therefore, a sudden increase in the rotational speed of the drive shaft 18 can be avoided.

(3) The information on the rotational speed commanded by the control unit 26 is simple as information for grasping the rotational speed of the drive shaft 18 (the rotational speed of the gear pump 31 and the expander 38).
(4) The second boiler 41 has a higher temperature than the first boiler 40, and the first boiler 42 is upstream of the first boiler 40 and the second boiler 41 among the high-pressure channels 42, 47, 45. By connecting the pressure detector 53, it becomes difficult to be affected by the heat of the first boiler 40 and the second boiler 41. Therefore, it is not necessary to take a special heat protection measure for the pressure detector 53, and an increase in the cost of the pressure detector 53 can be avoided.

  Next, a second embodiment of FIGS. 4 and 5 will be described. The same reference numerals are used for the same components as those in the first embodiment, and detailed description thereof is omitted. In the flowchart of FIG. 5, the same reference numerals are used for the same control steps, and detailed description thereof will be omitted.

  A region Z2 surrounded by the curves Kd and Ku and the end lines L1 and L2 in the graph of FIG. 4 is a rotational speed-pressure allowable region set as an allowable region. The upper side of the curve Ku is a high pressure region having a higher pressure than the rotation speed-pressure allowable region Z2. A set (Nu, Pu) of the rotational speed Nu and the pressure Pu is an example on the curve Ku. When the refrigerant pressure in the first flow path 42 is in the high pressure region above the curve Ku, it is a case where abnormal high pressure occurs due to clogging of foreign matter. A curve Ku is an index set for determining whether or not the refrigerant in the first flow path 42 has an abnormally high pressure.

  As shown in FIG. 5, the control unit 26 determines whether or not the set (Nx, Px) of the command rotational speed Nx commanded to the inverter 25 and the detected pressure Px is within a region Z2 shown in the graph of FIG. Judgment is made (step S21). When the set (Nx, Px) is within the rotation speed-pressure allowable region Z2 (YES in step S21), the control unit 26 proceeds to step S1. When the set (Nx, Px) is not within the rotation speed-pressure allowable range Z2 (NO in step S21), the control unit 26 proceeds to step S4.

  The pressure in the first flow path 42 may become abnormally high due to foreign matter clogging. The control unit 26 determines whether or not the set (Nx, Px) of the grasped pressure Px and the rotational speed Nx in the first flow path 42 is in a higher pressure region than the preset rotational speed-pressure allowable region Z2. Judgment is made. That is, since it is determined whether or not the pressure Px is too high according to the command rotational speed Nx (the rotational speeds of the gear pump 31 and the expander 38), it is accurately determined whether or not the refrigerant is in an abnormally high pressure state. be able to.

In the present invention, the following embodiments are also possible.
In the second embodiment, the region surrounded by the curves K2, Ku and the end lines L1, L2 is the rotation speed-pressure allowable region, and the set (Nx, Px) is not within this rotation speed-pressure allowable region. Alternatively, only the magnitude comparison between the pressure Px in the set (Nx, Px) and the preset pressure Pu may be performed.

The region Zo may be the rotation speed-pressure allowable region.
-The pressure in the connection channel 47 may be detected.
The pressure in the heat absorbers 401 and 411, the connection channel 47 or the suction channel 45 may be detected.

In place of the direction switching valve 52, an open / close valve may be provided in the middle of the bypass flow path 51.
The bypass channel 51 and the direction switching valve 52 may be omitted.
A rotation speed detection means for detecting the rotation speed of the drive shaft 18 may be provided, and this rotation speed detection means may be used as the rotation speed grasping means.

-A rotary electric machine may function only as a generator.
The present invention may be applied to a complex fluid machine in which a clutch is provided between the rotation shaft of the compressor and the drive shaft 18 so that the rotation of the drive shaft 18 can be transmitted to the rotation shaft of the compressor.

  ○ An expander of a type other than the vane type may be used as the expander. For example, an axial fan may be attached to the drive shaft 18 so that the refrigerant flows in the axial direction of the drive shaft 18 to rotate the axial fan and the drive shaft 18 integrally.

-An expander may be comprised by a movable scroll and a fixed scroll similarly to the scroll compressor provided with the movable scroll and a fixed scroll.
The present invention may be applied to Rankine cycle devices other than those for vehicles.

The technical idea that can be grasped from the above-described embodiment will be described below.
(A) A Rankine cycle device according to any one of claims 1 to 5, wherein a boiler is provided on the flow path, and the pressure detection means detects a pressure upstream of the boiler.

  10 ... Waste heat recovery device for vehicles as Rankine cycle device. 18 ... Drive shaft. 23: A motor generator as a rotating electric machine. 26: A control unit that is a rotation command control unit, a determination unit, and a rotation control unit as a rotation number grasping unit. 31 ... Gear pump as a pump. 38 ... Expander. 42: a first flow path constituting a high pressure flow path. 51: Bypass channel. 53 ... Pressure detector as pressure detecting means. Z1, Z2... Rotational speed-pressure allowable region. Px: Pressure. Nx: Number of rotations. Pair (Nx, Px).

Claims (5)

A rotating electrical machine that functions as at least a generator, an expander that applies a rotational force to the drive shaft of the rotating electrical machine using Rankine cycle working fluid, a pump that sucks and discharges the Rankine cycle working fluid, and A Rankine cycle device in which the expander and the pump rotate integrally with a rotation control means for controlling the rotation of the drive shaft;
Pressure detecting means for detecting the pressure in the high pressure flow path downstream of the pump and upstream of the expander;
A rotational speed grasping means for grasping the rotational speed of the drive shaft;
Determining means for determining whether a set of the rotational speed grasped by the rotational speed grasping means and the pressure detected by the pressure detecting means is in a preset rotational speed-pressure allowable region;
The rotation control means is a Rankine cycle device that performs stop control to reduce the rotation speed of the drive shaft to zero when the pressure in the set is in a lower pressure area than the rotation speed-pressure allowable area.   The Rankine cycle apparatus according to claim 1, wherein the rotation control means performs the stop control when the pressure in the set is in a higher pressure region than the rotation speed-pressure allowable region. A rotating electrical machine that functions as at least a generator, an expander that applies a rotational force to the drive shaft of the rotating electrical machine using Rankine cycle working fluid, a pump that sucks and discharges the Rankine cycle working fluid, and A Rankine cycle device in which the expander and the pump rotate integrally with a rotation control means for controlling the rotation of the drive shaft;
Pressure detecting means for detecting the pressure in the high pressure flow path downstream of the pump and upstream of the expander;
A rotational speed grasping means for grasping the rotational speed of the drive shaft;
Determining means for determining whether a set of the pressure detected by the pressure detecting means and the rotational speed grasped by the rotational speed grasping means is in a preset rotational speed-pressure allowable region;
The rotation control means is a Rankine cycle device that performs stop control to make the rotational speed of the drive shaft zero when the pressure in the set is in a higher pressure region than the rotational speed-pressure allowable region.   A bypass passage connecting the downstream side of the expander and the high-pressure passage is provided, and an opening / closing means for opening and closing the bypass passage is provided, and the stop control is performed so as to open the bypass passage. The Rankine cycle apparatus according to any one of claims 1 to 3, wherein the opening / closing means is controlled, and thereafter, the rotational speed of the drive shaft is made zero.   The Rankine cycle apparatus according to any one of claims 1 to 4, wherein the rotation control means is a rotation speed command control means that commands and controls the rotation speed of the rotating electrical machine.

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