The present invention relates to a Rankine cycle system.
Conventionally, it is disclosed in JP2001-182504A to mount an evaporator and an expander on an engine in an on-vehicle Rankine cycle system.
The evaporator and the expander are connected to another member, e.g. a condenser mounted on a vehicle body via pipes. Since a member mounted on an engine and a member mounted on the vehicle body differ in vibration frequency, the member mounted on the engine and that mounted on the vehicle body are connected by a flexible pipe. Since flexible pipes are more expensive than pipes having high rigidity such as stainless steel pipes and aluminum pipes, the usage thereof is preferably reduced.
However, in the above invention, no consideration is made on such a point and there is a problem of increasing the cost of the Rankine cycle system.
The present invention was developed to solve the above problem and aims to reduce the cost of a Rankine cycle system by reducing the usage of flexible pipes.
A Rankine cycle system according to one aspect of the present invention includes a refrigerant pump which is mounted on an engine and is configured to feed refrigerant, a heat exchanger which is mounted on the engine and is configured to recover exhaust heat of the engine to the refrigerant, an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger, and a condenser which is mounted on a vehicle body and is configured to condense the refrigerant expanded by the expander. In the Rankine cycle system, the expander and the condenser, and the condenser and the refrigerant pump are connected by flexible pipes having higher flexibility than other pipes.
Embodiments of the present invention and advantages thereof are described in detail below with reference to the accompanying drawings.
In the hybrid vehicle 1, an engine 2, a motor generator 81 and an automatic transmission 82 are coupled in series and an output of the automatic transmission 82 is transmitted to drive wheels 85 via a propeller shaft 83 and a differential gear 84. A first drive shaft clutch 86 is provided between the engine 2 and the motor generator 81. Further, one of frictional engagement elements of the automatic transmission 82 is configured as a second drive shaft clutch 87. The first and second drive shaft clutches 86, 87 are connected to an engine controller 71, and connection and disconnection (connected state) thereof are controlled according to a driving condition of the hybrid vehicle 1. In the hybrid vehicle 1, as shown in
The engine 2 is mounted on the vehicle body by being fixed to a frame member forming a vehicle body skeleton of the hybrid vehicle 1 via an unillustrated engine mount. The engine mount functions to reduce (damp) vibration transmitted between the engine 2 and the vehicle body and makes it difficult to transmit the vibration of the engine 2 to the vehicle body and the vibration of the vehicle body to the engine 2. As a result, the engine 2 and the vehicle body produce different types of vibration, wherefore an engine 2 side component fixed to the engine 2 and a vehicle body side component fixed to the vehicle body also produce different types of vibration. Even components generally connected by a connecting component having high rigidity need to be connected by a connecting component having high flexibility (excellent in flexibility) to absorb relative displacements caused by vibration when they are separately mounted on the engine 2 and the vehicle body.
First, an engine cooling water circuit is described based on
The heat exchanger 36 for performing heat exchange with the refrigerant of the Rankine cycle 31 is provided in the bypass cooling water passage 14. This heat exchanger 36 is formed by integrating an evaporator and a superheater. Specifically, in the heat exchanger 36, two cooling water passages 36a, 36b are arranged substantially in a row and a refrigerant passage 36c in which the refrigerant of the Rankine cycle 31 flows is provided adjacent to the cooling water passages 36a, 36b so as to enable heat exchange between the refrigerant and the cooling water. Further, each passage 36a, 36b, 36c is so configured that the refrigerant of the Rankine cycle 31 and the cooling water flow in opposite directions when the entire heat exchanger 36 is viewed from above.
In detail, one cooling water passage 36a located on an upstream side (left side of
The cooling water having passed through the exhaust heat recovery device 22 via the second bypass cooling water passage 25 is introduced to the other cooling water passage 36b on a downstream side (right side of
A cooling water passage 22a of the exhaust heat recovery device 22 is provided adjacent to the exhaust pipe 5. By introducing the cooling water at the exit of the engine 2 to the cooling water passage 22a of the exhaust heat recovery device 22, the cooling water can be heated, for example, up to 110 to 115° C. by the high-temperature exhaust air. The cooling water passage 22a is so configured that the exhaust air and the cooling water flow in opposite directions when the entire exhaust heat recovery device 22 is viewed from above.
A control valve 26 is disposed in the second bypass cooling water passage 25 including the exhaust heat recovery device 22. An opening of this control valve 26 is reduced when a temperature detected by a cooling water temperature sensor 74 at the exit of the engine 2 reaches a predetermined value or higher so that an engine water temperature indicating the temperature of the cooling water in the engine 2 does not exceed a permissible temperature (e.g. 100° C.) for preventing, for example, efficiency deterioration of the engine 2 and the occurrence of knocking. When the engine water temperature approaches the permissible temperature, the amount of the cooling water passing through the exhaust heat recovery device 22 is reduced. This can reliably prevent the engine water temperature from exceeding the permissible temperature.
On the other hand, if the cooling water temperature increased by the exhaust heat recovery device 22 becomes too high and the cooling water evaporates (boils) due to a reduction in the flow rate of the second bypass cooling water passage 25, the flow of the cooling water in the cooling water passage may become poor and component temperatures may excessively increase. To avoid this, the bypass exhaust pipe 6 bypassing the exhaust heat recovery device 22 is provided and a thermostat valve 7 for controlling an amount of the exhaust air passing through the exhaust heat recovery device 22 and an amount of the exhaust air passing through the bypass exhaust pipe 6 is provided in a branched part of the bypass exhaust pipe 6. Specifically, a valve opening of the thermostat valve 7 is adjusted based on the temperature of the cooling water coming out from the exhaust heat recovery device 22 so that the temperature of the cooling water coming out from the exhaust heat recovery device 22 does not exceed a predetermined temperature (e.g. boiling temperature of 120°).
The heat exchanger 36, the thermostat valve 7 and the exhaust heat recovery device 22 are united into the exhaust heat recovery unit 23 and arranged at intermediate positions of the exhaust pipe under a substantially central part of a floor in a vehicle width direction. The thermostat valve 7 may be a relatively simple temperature sensitive valve using a bimetal or the like or may be a control valve controlled by a controller to which a temperature sensor output is input. Since an adjustment of a heat exchange amount from the exhaust air into the cooling water by the thermostat valve 7 causes a relatively long delay, it is difficult to prevent the engine water temperature from exceeding the permissible temperature if the thermostat valve 7 is singly adjusted. However, since the control valve 26 in the second bypass cooling water passage 25 is controlled based on the engine water temperature (exit temperature), a heat recovery amount can be quickly reduced to reliably prevent the engine water temperature from exceeding the permissible temperature. Further, if there is a margin between the engine water temperature and the permissible temperature, an exhaust heat recovery amount can be increased by performing heat exchange until the temperature of the cooling water coming out from the exhaust heat recovery device 22 reaches a high temperature (e.g. 110 to 115° C.) exceeding the permissible temperature of the engine water temperature. The cooling water coming out from the cooling water passage 36b joins the first bypass cooling water passage 24 via the second bypass cooling water passage 25.
If the temperature of the cooling water flowing from the bypass cooling water passage 14 toward the thermostat valve 15 is sufficiently reduced, for example, by heat exchange with the refrigerant of the Rankine cycle 31 in the heat exchanger 36, the valve opening of the thermostat valve 15 on the side of the cooling water passage 13 is reduced and the amount of the cooling water passing through the radiator 11 is relatively reduced. Conversely, if the temperature of the cooling water flowing from the bypass cooling water passage 14 toward the thermostat valve 15 is increased such as because the Rankine cycle 31 is not operated, the valve opening of the thermostat valve 15 on the side of the cooling water passage 13 is increased and the amount of the cooling water passing through the radiator 11 is relatively increased. Based on such an operation of the thermostat valve 15, the cooling water temperature of the engine 2 is appropriately maintained and heat is appropriately supplied (recovered) to the Rankine cycle 31.
Next, the Rankine cycle 31 is described. Here, the Rankine cycle 31 is configured not as a simple Rankine cycle, but as a part of the integrated cycle 30 integrated with the refrigeration cycle 51. The Rankine cycle 31 as a basis is described first and the refrigeration cycle 51 is then mentioned.
The Rankine cycle 31 is a system for recovering the exhaust heat of the engine 2 by the refrigerant using the cooling water of the engine 2 and regenerating the recovered exhaust heat as power. The Rankine cycle 31 includes a refrigerant pump 32, the heat exchanger 36 as a superheater, an expander 37 and the condenser 38 and each constituent element is connected by refrigerant passages 41 to 44 in which the refrigerant (R134a, etc.) is circulated. The refrigerant passages 41 to 44 are generally formed by ordinary metal pipes (steel pipes) which easily ensure refrigerant sealability and have relatively high rigidity, but flexible pipes having high flexibility are used as some of them in the present embodiment. This is described in detail later.
A shaft of the refrigerant pump 32 is arranged to be coupled to an output shaft of the expander 37 on the same axis, the refrigerant pump 32 is driven by an output (power) generated by the expander 37 and the generated power is supplied to an output shaft (crankshaft) of the engine 2 (see
An electromagnetic clutch (hereinafter, this clutch is referred to as an “expander clutch”) 35 (first clutch) is provided between the pump pulley 33 and the refrigerant pump 32 to make the refrigerant pump 32 and the expander 37 connectable to and disconnectable from the engine 2 (see
The refrigerant from the refrigerant pump 32 is supplied to the heat exchanger 36 via the refrigerant passage 41. The heat exchanger 36 is a heat exchanger for performing heat exchange between the cooling water of the engine 2 and the refrigerant and evaporating and overheating the refrigerant.
The refrigerant from the heat exchanger 36 is supplied to the expander 37 via the refrigerant passage 42. The expander 37 is a steam turbine for converging heat into rotational energy by expanding the evaporated and overheated refrigerant. The power recovered by the expander 37 drives the refrigerant pump 32 and is transmitted to the engine 2 via a belt transmission mechanism to assist the rotation of the engine 2.
The refrigerant from the expander 37 is supplied to the condenser 38 via refrigerant passages 43a, 43b. The condenser 38 is a heat exchanger for performing heat exchange between outside air and the refrigerant and cooling and liquefying the refrigerant. Thus, the condenser 38 is arranged in parallel with the radiator 11 and cooled by a radiator fan 12. The condenser 38 is mounted on the vehicle body.
The refrigerant passage 43a is connected to the expander 37. The refrigerant passage 43b connects the refrigerant passage 43a and the condenser 38. The refrigerant passages 43a, 43b are connected at a refrigeration cycle junction 46 to be described later.
The refrigerant passage 43a connecting the engine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 43b to absorb a relative displacement caused by vibration. High flexibility means low rigidity and being freely deformable. To provide flexibility, the flexible pipe has a bellows-like shape or is made of a material which is soft and excellent in flexibility. Thus, the refrigerant passage 43a can be freely bent at any intermediate position and can absorb vibration if the vibration is transmitted. A part of the refrigerant passage 43a on the side of the expander 37 mounted on the engine 2 vibrates together with the engine 2 and the expander 37.
The refrigerant passage 43b is a pipe connected to the condenser 38 and having lower flexibility, i.e. higher rigidity than the refrigerant passage 43a such as a stainless steel pipe or an aluminum pipe. The refrigerant passage 43b vibrates together with the condenser 38 mounted on the vehicle body.
The refrigerant passage 43a is connected to the expander 37 mounted on the engine 2. Further, the refrigerant passage 43b is connected to the condenser 38 mounted on the vehicle body. Thus, when the vehicle is driven, a vibration frequency of the refrigerant passage 43a and that of the refrigerant passage 43b differ. In the present embodiment, the refrigerant passage 43a is formed by a flexible pipe for refrigerant, whereby a vibrational difference between the part of the refrigerant passage 43a on the side of the engine 2 and the refrigerant passage 43b is absorbed by the refrigerant passage 43a.
The refrigerant liquefied by the condenser 38 is returned to the refrigerant pump 32 via refrigerant passages 44a, 44b. The refrigerant returned to the refrigerant pump 32 is fed to the heat exchanger 36 again by the refrigerant pump 32 and circulates through each constituent element of the Rankine cycle 31.
The refrigerant passage 44a is connected to the condenser 38. The refrigerant passage 44b connects the refrigerant passage 43a and the refrigerant pump 32. The refrigerant passages 44a, 44b are connected at a refrigeration cycle junction 45 to be described later.
The refrigerant passage 44a is, for example, a stainless steel pipe or an aluminum pipe having lower flexibility than the refrigerant passage 44b. The refrigerant passage 44a vibrates together with the condenser 38.
The refrigerant passage 44b connecting the engine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 44a to absorb a relative displacement caused by vibration. A part of the refrigerant passage 44b on the side of the engine 2 vibrates together with the engine 2 by having the vibration of the engine 2 transmitted thereto.
By forming the refrigerant passage 44b by the flexible pipe for refrigerant, a vibrational difference between the refrigerant passages 44a, 44b can be absorbed by the refrigerant passage 44b.
Next, the refrigeration cycle 51 is described. Since the refrigeration cycle 51 shares the refrigerant circulating in the Rankine cycle 31, the refrigeration cycle 51 is integrated with the Rankine cycle 31 and the configuration thereof is simple. Specifically, the refrigeration cycle 51 includes a compressor 52, the condenser 38 and an evaporator 55.
The compressor 52 is a fluid machine for compressing the refrigerant of the refrigeration cycle 51 at high temperature and high pressure. The compressor 52 is mounted on the vehicle body. The compressor 52 is an electric compressor and power is supplied thereto from an unillustrated battery or the like.
The refrigerant from the compressor 52 is supplied to the condenser 38 via the refrigerant passage 43b after joining the refrigerant passage 43a at the refrigeration cycle junction 46 via a refrigerant passage 56. The refrigerant passage 56 is formed by a general metal pipe (steel pipe) having relatively high rigidity. The condenser 38 is a heat exchanger for condensing and liquefying the refrigerant by heat exchange with outside air. The liquid refrigerant from the condenser 38 is supplied to the evaporator 55 via a refrigerant passage 57 branched off from the refrigerant passage 44a at the refrigeration cycle junction 45. The refrigerant passage 57 is also formed by a general metal pipe (steel pipe) having relatively high rigidity. The evaporator 55 is arranged in a case of an air conditioning unit in the same manner as an unillustrated heater core. The evaporator 55 is a heat exchanger for evaporating the liquid refrigerant from the condenser 38 and cooling air conditioning air from a blower fan by latent heat of evaporation.
The refrigerant evaporated by the evaporator 55 is returned to the compressor 52 via a refrigerant passage 58. It should be noted that a mixing ratio of the air conditioning air cooled by the evaporator 55 and that heated by the heater core is changed according to an opening of an air mix door to adjust the temperature to a temperature set by a passenger.
The integrated cycle 30 composed of the Rankine cycle 31 and the refrigeration cycle 51 appropriately includes various valves at intermediate positions of the circuit to control the refrigerant flowing in the cycle. For example, to control the refrigerant circulating in the Rankine cycle 31, a pump upstream valve 61 is provided in the refrigerant passage 44b allowing communication between the refrigeration cycle junction 45 and the refrigerant pump 32 and an expander upstream valve 62 is provided in the refrigerant passage 42 allowing communication between the heat exchanger 36 and the expander 37. Further, a check valve 63 for preventing a reverse flow of the refrigerant from the heat exchanger 36 to the refrigerant pump 32 is provided in the refrigerant passage 41 allowing communication between the refrigerant pump 32 and the heat exchanger 36. A check valve 64 for preventing a reverse flow of the refrigerant from the refrigeration cycle junction 46 to the expander 37 is also provided in the refrigerant passage 43a allowing communication between the expander 37 and the refrigeration cycle junction 46. Further, an expander bypass passage 65 is provided which bypasses the expander 37 from a side upstream of the expander upstream valve 62 and joins at a side upstream of the check valve 64, and a bypass valve 66 is provided in this expander bypass passage 65. Furthermore, a pressure regulating valve 68 is provided in a passage 67 bypassing the bypass valve 66. Also in the refrigeration cycle 51, an air conditioning circuit valve 69 is provided in the refrigerant passage 57 connecting the refrigeration cycle junction 45 and the evaporator 55.
Any of the above four valves 61, 62, 66 and 69 is an electromagnetic on-off valve. To the engine controller 71 are input a signal indicating a pressure upstream of the expander detected by a pressure sensor 72, a signal indicating a refrigerant pressure Pd at the exit of the condenser 38 detected by a pressure sensor 73, a rotation speed signal of the expander 37, etc. In the engine controller 71, the compressor 52 of the refrigeration cycle 51 and the radiator fan 12 are controlled and the opening and closing of the above four electromagnetic on-off valves 61, 62, 66 and 69 are controlled based on each of these input signals according to a predetermined driving condition.
For example, an expander torque (regenerative power) is predicted based on the pressure upstream of the expander detected by the pressure sensor 72 and the expander rotation speed, and the expander clutch 35 is engaged when this predicted expander torque is positive (the rotation of the engine output shaft can be assisted) and released when the predicted expander torque is zero or negative. The expander torque can be predicted with high accuracy based on the sensor detected pressure and the expander rotation speed as compared with the case where the expander torque (regenerative power) is predicted from the exhaust temperature, and the expander clutch 35 can be properly engaged/released according to a generation state of the expander torque (for further details, see JP2010-190185A).
The above four on-off valves 61, 62, 66 and 69 and two check valves 63, 64 are refrigeration system valves. Functions of these refrigeration system valves are shown anew in
In
The check valve 63 upstream of the heat exchanger 36 is for maintaining the refrigerant supplied to the expander 37 at a high pressure in cooperation with the bypass valve 66, the pressure regulating valve 68 and the expander upstream valve 62. Under a condition that the regeneration efficiency of the Rankine cycle is low, the operation of the Rankine cycle is stopped and the circuit is closed in a section before and after the heat exchanger, whereby the refrigerant pressure during the stop is increased so that the Rankine cycle can be quickly restarted utilizing the high-pressure refrigerant. The pressure regulating valve 68 functions as a relief valve for allowing the refrigerant having reached an excessively high pressure to escape by being opened when the pressure of the refrigerant supplied to the expander 37 becomes excessively high.
The check valve 64 downstream of the expander 37 is for preventing an uneven distribution of the refrigerant to the Rankine cycle 31 in cooperation with the aforementioned pump upstream valve 61. If the engine 2 is not warm yet immediately after the operation of the hybrid vehicle 1 is started, the temperature of the Rankine cycle 31 is lower than that of the refrigeration cycle 51 and the refrigerant may be unevenly distributed toward the Rankine cycle 31. Although a probability of uneven distribution toward the Rankine cycle 31 is not very high, there is a request to resolve even a slightly uneven distribution of the refrigerant to secure the refrigerant of the refrigeration cycle 51, for example, immediately after the start of the vehicle operation in summer since it is wished to quickly cool vehicle interior and cooling capacity is required most. Accordingly, the check valve 64 is provided to prevent the uneven distribution of the refrigerant toward the Rankine cycle 31.
The compressor 52 is not so structured that the refrigerant can freely pass when the drive is stopped, and can prevent an uneven distribution of the refrigerant to the refrigeration cycle 51 in cooperation with the air conditioning circuit valve 69. This is described. When the operation of the refrigeration cycle 51 is stopped, the refrigerant moves from the Rankine cycle 31 that is in steady operation and has a relatively high temperature to the refrigeration cycle 51, whereby the refrigerant circulating in the Rankine cycle 31 may become insufficient. In the refrigeration cycle 51, the temperature of the evaporator 55 is low immediately after the cooling is stopped and the refrigerant tends to stay in the evaporator 55 that has a relatively large volume and a low temperature. In this case, the uneven distribution of the refrigerant to the refrigeration cycle 51 is prevented by stopping the drive of the compressor 52 to block a movement of the refrigerant from the condenser 38 to the evaporator 55 and closing the air conditioning circuit valve 69.
Next,
Next, a basic operation method of the Rankine cycle 31 is described with reference to
First,
In both
Effects of the first embodiment of the present invention are described.
Particularly, the present embodiment is not only configured to be able to drive the refrigerant pump 32 by the engine 2 by mounting the refrigerant pump 32 on the engine 2, but also configured to be able to drive the refrigerant pump 32 by a regenerative output of the expander 37 by mounting the expander 37 on the engine 2, and energy efficiency can be improved by enabling the refrigerant pump 32 to be driven also utilizing the regenerative output of the expander 37 while increasing a degree of freedom in the operation of the Rankine cycle 31 by enabling the refrigerant pump 32 to be driven by the power of the engine 2. Since the heat exchanger 36 provided between the refrigerant pump 32 and the expander 37 is mounted on the engine 2 under such an assumption, the refrigerant pump 32 and the heat exchanger 36, and the heat exchanger 36 and the expander 37 can be connected by the passages (conduits) 101 having relatively high rigidity, and only the expander 37 and the condenser 38, and the condenser 38 and the refrigerant pump 32 are connected by the flexible pipes 100 having high flexibility. This can suppress cost by reducing the number of the relatively expensive flexible pipes 100. Specifically, only two flexible pipes 100 are provided at intermediate positions of the circuit of the Rankine cycle 31.
Specifically, at least a part of the refrigerant passage 43a connected to the expander 37 mounted on the engine 2 is formed by a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 43b connected to the condenser 38 mounted on the vehicle body. This enables the refrigerant passage 43a to absorb a vibrational difference between the part of the refrigerant passage 43a on the side of the engine 2 and the refrigerant passage 43b. Further, the refrigerant passage 43b can be formed by a metal pipe less expensive than the flexible pipe for refrigerant such as a copper pipe, a stainless steel pipe or an aluminum pipe, and the number of the expensive flexible pipes for refrigerant can be reduced. Thus, the cost of the integrated cycle 30 can be reduced.
By using the flexible pipe for refrigerant at least in a part of the refrigerant passage 43a, the length of the pipe connecting the expander 37 and the condenser 38 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of the integrated cycle 30 can be improved.
At least a part of the refrigerant passage 44b connected to the refrigerant pump 32 mounted on the engine 2 is formed by a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 44a connected to the condenser 38. This enables the refrigerant passage 44b to absorb a vibrational difference between the refrigerant passage 44a and the part of the refrigerant passage 44b on the side of the engine 2. Further, the refrigerant passage 44a can be formed by a metal pipe less expensive than the flexible pipe for refrigerant, and the number of the expensive flexible pipes for refrigerant can be reduced. Thus, the cost of the integrated cycle 30 can be reduced.
By using the flexible pipe for refrigerant at least in a part of the refrigerant passage 43a, the length of the pipe connecting the condenser 38 and the refrigerant pump 32 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of the integrated cycle 30 can be improved.
By forming the refrigerant passage 43a by a flexible pipe for refrigerant and forming the refrigerant passage 43b, for example, by a metal pipe in the integrated cycle 30 in which the output shaft of the expander 37 and that of the engine 2 are configured to be able to transmit power, the above effects can be obtained more.
Next, a second embodiment of the present invention is described using
A compressor 59 is mounted on an engine 2 and driven by the engine 2. As shown in
A refrigerant passage 56 connected to the compressor 59 is a flexible pipe for refrigerant having higher flexibility than a refrigerant passage 43b.
A refrigerant passage 58 provided between the compressor 59 and an evaporator 55 and connected to the compressor 59 is a flexible pipe for refrigerant similarly to the refrigerant passage 56.
When the compressor 59 is mounted on the engine 2, a vibration frequency of the refrigerant passage 56 connected to the compressor 59 and that of the refrigerant passage 43b connected to a condenser 38 differ when the vehicle is driven. In the present embodiment, a vibrational difference between the refrigerant passages 56 and 43b is absorbed by forming the refrigerant passage 56 by the flexible pipe for refrigerant.
Effects of the second embodiment of the present invention are described.
Specifically, at least a part of the refrigerant passage 56 is formed by the flexible pipe for refrigerant and the refrigerant passage 56 is connected to the refrigerant passage 43b at a refrigeration cycle junction 46. This enables the refrigerant passage 43b to absorb a vibrational difference between the refrigerant passages 43b and 56.
Next, a third embodiment of the present invention is described.
The third embodiment is described, centering on parts different from the second embodiment.
In the third embodiment, a refrigerant passage 43b is formed by a flexible pipe having higher flexibility than refrigerant passages 43a and 56. Further, the refrigerant passages 43a and 56 are formed, for example, by stainless steel pipes or aluminum pipes having low flexibility.
Effects of the third embodiment of the present invention are described.
Specifically, a refrigerant passage 43b connected to the condenser 38 is formed by a flexible pipe for refrigerant, and a refrigerant passage 43a connected to the expander 37 and a refrigerant passage 56 connected to the compressor 59 are formed, for example, by stainless pipes or aluminum pipes less expensive than flexible pipes for refrigerant. This enables the absorption of a vibrational difference between the refrigerant passage 43b and the refrigerant passages 43a, 56. Further, the refrigerant passages 43a, 56 can be formed by inexpensive pipes and the cost of the integrated cycle 30 can be reduced.
It should be noted that a refrigerant passage 44a may be formed by a flexible pipe for refrigerant and a refrigerant passage 44b may be formed by a stainless steel pipe or an aluminum pipe.
By using flexible pipes for refrigerant at least as some of the refrigerant passages, the length of the pipes connecting the expander 37 or the compressor 59 and the condenser 38 and the pipe connecting the condenser 38 and a refrigerant pump 32 can be shortened, a pressure loss in the pipes can be reduced and the efficiency of the integrated cycle 30 can be improved.
The present invention is not limited to the above embodiments. For example, a pipe configured to include a flexible pipe for refrigerant having high flexibility in a part (at an intermediate position) of a general metal pipe may be used as a passage pipe having high flexibility to absorb a relative displacement caused by vibration.
Although the embodiments of the present invention have been described above, the above embodiments are only an illustration of some application examples of the present invention and not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.
This application claims a priority of Japanese Patent Application No. 2011-216772 filed with the Japan Patent Office on Sep. 30, 2011, all the contents of which are hereby incorporated by reference.
Number | Date | Country | Kind |
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2011-216772 | Sep 2011 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2012/072725 | 9/6/2012 | WO | 00 | 1/16/2014 |