JP2013076373A - Rankine cycle system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Rankine cycle system reduced in cost.SOLUTION: The Rankine cycle system 30 comprises: a refrigerant pump 32 attached to an engine 2 and sending out a refrigerant: a heat exchanger 36 attached to the engine 2 and recovering the waste heat of the engine 2 to the refrigerant; an expander 37 attached to the engine 2 and converting the waste heat recovered to the refrigerant to power by expanding the refrigerant which is raised in temperature by the heat exchanger 36; and a condenser 38 attached to a vehicle body and condensing the refrigerant which is expanded by the expander 37. A clearance between the expander 37 and the condenser 38 and a clearance between the condenser 38 and the refrigerant pump 32 are connected to each other by flexible piping 43a, 44b which are larger in flexibility than others.

Description

  The present invention relates to a Rankine cycle system.

  Conventionally, in an in-vehicle Rankine cycle system, Patent Document 1 discloses an evaporator and an expander that are attached to an engine.

JP 2001-182504 A

  The evaporator and the expander are connected to other members, such as a condenser attached to the vehicle body, via a pipe. Since the vibration frequency differs between the member attached to the engine and the member attached to the vehicle body, the member attached to the engine and the member attached to the vehicle body are connected by flexible piping. Since flexible piping is more expensive than piping having high rigidity such as stainless steel piping and aluminum piping, it is desirable to reduce the amount of use.

  However, in the above invention, such a point is not considered, and there is a problem that the cost of the Rankine cycle system is increased.

  The present invention was invented to solve such problems, and aims to reduce the amount of flexible piping used and the cost of the Rankine cycle system.

  A Rankine cycle system according to an aspect of the present invention includes a refrigerant pump that is attached to an engine and delivers a refrigerant, a heat exchanger that is attached to the engine and collects waste heat of the engine into the refrigerant, and is attached to the engine and is heated. An expander that converts waste heat recovered by the refrigerant by expanding the refrigerant whose temperature has been increased by the exchanger into power, and a condenser that is attached to the vehicle body and condenses the refrigerant expanded by the expander. The Rankine cycle system connects between an expander and a condenser, and between a condenser and a refrigerant pump with flexible piping that is more flexible than others.

  According to the present invention, the number of relatively expensive flexible pipes can be reduced and the cost can be reduced.

It is a schematic block diagram of the integration cycle of 1st Embodiment of this invention. It is a schematic sectional drawing of the expander pump which integrated the pump and the expander. It is a schematic sectional drawing of a refrigerant pump. It is a schematic sectional drawing of an expander. It is the schematic which shows the function of a refrigerant | coolant type | system | group valve | bulb. It is a schematic block diagram of a hybrid vehicle. It is a schematic perspective view of an engine. It is the schematic which looked at arrangement | positioning of an exhaust pipe from the downward direction of the vehicle. It is a characteristic view of a Rankine cycle operation area. It is a characteristic view of a Rankine cycle operation area. It is the figure which showed typically the mode of piping of the integrated cycle of 1st Embodiment. It is a schematic block diagram of the hybrid vehicle of 2nd Embodiment of this invention. It is a schematic block diagram of the integration cycle of 2nd Embodiment of this invention. It is the figure which showed typically the mode of piping of the integrated cycle of 2nd Embodiment. It is the figure which showed typically the mode of piping of the integrated cycle of 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing the entire system of a Rankine cycle 31 which is a premise of the present invention. The Rankine cycle 31 of FIG. 1 is configured to share the refrigerant and the condenser 38 with the refrigeration cycle 51, and the Rankine cycle system in which the Rankine cycle 31 and the refrigeration cycle 51 are integrated is hereinafter expressed as an integrated cycle 30. To do. FIG. 4 is a schematic configuration diagram of the hybrid vehicle 1 on which the integrated cycle 30 is mounted. The integrated cycle 30 includes a circuit (passage) through which the refrigerant of the Rankine cycle 31 and the refrigeration cycle 51 circulates and components such as a pump, an expander, and a condenser provided in the middle of the circuit, and a circuit for cooling water and exhaust. It shall refer to the entire system including (passage).

  In the hybrid vehicle 1, the engine 2, the motor generator 81, and the automatic transmission 82 are connected in series, and the output of the automatic transmission 82 is transmitted to the drive wheels 85 via the propeller shaft 83 and the differential gear 84. A first drive shaft clutch 86 is provided between the engine 2 and the motor generator 81. One of the frictional engagement elements of the automatic transmission 82 is configured as a second drive shaft clutch 87. The first drive shaft clutch 86 and the second drive shaft clutch 87 are connected to the engine controller 71, and their connection / disconnection (connected state) is controlled according to the driving conditions of the hybrid vehicle. In the hybrid vehicle 1, as shown in FIG. 7B, when the vehicle speed is in the EV traveling region where the efficiency of the engine 2 is poor, the engine 2 is stopped, the first drive shaft clutch 86 is disconnected, and the second drive shaft clutch 87 is connected. Thus, the hybrid vehicle 1 is caused to travel only by the driving force of the motor generator 81. On the other hand, when the vehicle speed deviates from the EV travel region and shifts to the Rankine cycle operation region, the engine 2 is operated to operate the Rankine cycle 31 (described later). The engine 2 includes an exhaust passage 3, and the exhaust passage 3 includes an exhaust manifold 4 and an exhaust pipe 5 connected to a collective portion of the exhaust manifold 4. The exhaust pipe 5 branches off from the bypass exhaust pipe 6 on the way, and the exhaust pipe 5 in the section bypassed by the bypass exhaust pipe 6 has a waste heat recovery unit for exchanging heat between the exhaust and the cooling water. 22. As shown in FIG. 6, the waste heat recovery unit 22 and the bypass exhaust pipe 6 are disposed between the underfloor catalyst 88 and the sub muffler 89 downstream thereof as a waste heat recovery unit 23 in which these are integrated.

  The engine 2 is fixed to a frame member that forms the body frame of the hybrid vehicle 1 via an engine mount (not shown) and is mounted on the vehicle body. The engine mount plays a role of reducing (attenuating) vibration transmitted between the engine 2 and the vehicle body, making it difficult for the vibration of the engine 2 to be transmitted to the vehicle body and making the vibration of the vehicle body difficult to transmit to the engine 2. As a result, since the engine 2 and the vehicle body generate different vibrations, the engine 2 side component fixed to the engine 2 and the vehicle body side component fixed to the vehicle body also generate different vibrations. In general, even if the parts are connected with a connection part having high rigidity, when they are separately mounted on the engine 2 side and the vehicle body side, they absorb relative displacement due to vibration, and thus have high flexibility ( It is necessary to connect with connecting parts (excellent flexibility).

  First, the engine coolant circuit will be described with reference to FIG. The cooling water of about 80 to 90 ° C. leaving the engine 2 flows separately into a cooling water passage 13 that passes through the radiator 11 and a bypass cooling water passage 14 that bypasses the radiator 11. Thereafter, the two flows are merged again by a thermostat valve 15 that determines the distribution of the flow rate of the cooling water flowing through both passages 13 and 14, and then returns to the engine 2 via the cooling water pump 16. The cooling water pump 16 is driven by the engine 2 and its rotation speed is synchronized with the engine rotation speed. The thermostat valve 15 relatively increases the amount of cooling water passing through the radiator 11 by increasing the valve opening on the cooling water passage 13 side when the cooling water temperature is high, and on the cooling water passage 13 side when the cooling water temperature is low. The amount of cooling water passing through the radiator 11 is relatively reduced by reducing the valve opening. When the coolant temperature is particularly low, such as before the engine 2 is warmed up, the radiator 11 is completely bypassed and the entire amount of coolant flows through the bypass coolant passage 14 side. On the other hand, the valve opening on the bypass cooling water passage 14 side is not fully closed, and when the flow rate of the cooling water flowing through the radiator 11 is increased, the flow rate of the cooling water flowing through the bypass cooling water passage 14 is However, the thermostat valve 15 is configured so that the flow does not stop completely. A bypass cooling water passage 14 that bypasses the radiator 11 is branched from the cooling water passage 13 and directly connected to a heat exchanger 36, which will be described later, and from the cooling water passage 13 to recover waste heat. The second bypass cooling water passage 25 connected to the heat exchanger 36 after passing through the vessel 22.

  The bypass cooling water passage 14 includes a heat exchanger 36 that exchanges heat with the refrigerant of the Rankine cycle 31. This heat exchanger 36 is an integrated evaporator and superheater. That is, two cooling water passages 36a and 36b are arranged in a row in the heat exchanger 36, and a refrigerant passage 36c through which the refrigerant in the Rankine cycle 31 flows so that heat exchange between the refrigerant and the cooling water is possible. It is provided adjacent to 36b. Further, the passages 36a, 36b, and 36c are configured so that the refrigerant and the cooling water of the Rankine cycle 31 are in opposite directions when viewed from the whole heat exchanger 36.

  Specifically, one cooling water passage 36 a located on the upstream side (left side in FIG. 1) for the refrigerant of Rankine cycle 31 is interposed in the first bypass cooling water passage 24. The left side portion of the heat exchanger composed of the cooling water passage 36a and the refrigerant passage portion adjacent to the cooling water passage 36a flows through the refrigerant passage 36c by directly introducing the cooling water from the engine 2 into the cooling water passage 36a. It is an evaporator for heating the refrigerant of Rankine cycle 31.

  Cooling water that has passed through the waste heat recovery device 22 is introduced into the other cooling water passage 36b located on the downstream (right side in FIG. 1) side of the refrigerant in the Rankine cycle 31 via the second bypass cooling water passage 25. The right side portion of the heat exchanger (downstream side for the refrigerant of Rankine cycle 31) composed of the cooling water passage 36b and the refrigerant passage portion adjacent to the cooling water passage 36b is a cooling water obtained by further heating the cooling water at the outlet of the engine 2 by exhaust gas. Is a superheater that superheats the refrigerant flowing through the refrigerant passage 36c by introducing the refrigerant into the cooling water passage 36b.

  The cooling water passage 22 a of the waste heat recovery unit 22 is provided adjacent to the exhaust pipe 5. By introducing the cooling water at the outlet of the engine 2 into the cooling water passage 22a of the waste heat recovery unit 22, the cooling water can be heated to, for example, about 110 to 115 ° C. by high-temperature exhaust. The cooling water passage 22a is configured so that the exhaust and cooling water flow in opposite directions when the waste heat recovery device 22 is viewed from the top.

  A control valve 26 is interposed in the second bypass cooling water passage 25 provided with the waste heat recovery unit 22. Cooling water temperature at the outlet of the engine 2 so that the engine water temperature, which indicates the temperature of the cooling water inside the engine 2, does not exceed the allowable temperature (for example, 100 ° C.) for preventing deterioration of the efficiency of the engine 2 or knocking When the detected temperature of the sensor 74 becomes equal to or higher than a predetermined value, the opening degree of the control valve 26 is decreased. When the engine water temperature approaches the permissible temperature, the amount of cooling water passing through the waste heat recovery device 22 is reduced, so that it is possible to reliably prevent the engine water temperature from exceeding the permissible temperature.

  On the other hand, if the flow rate of the second bypass cooling water passage 25 is decreased, the cooling water temperature rising by the waste heat recovery device 22 is excessively increased and the cooling water is evaporated (boiling). There is a risk that the flow of the cooling water will deteriorate and the component temperature will rise excessively. In order to avoid this, a bypass exhaust pipe 6 that bypasses the waste heat recovery unit 22, and a thermostat valve 7 that controls the exhaust passage amount of the waste heat recovery unit 22 and the exhaust passage amount of the bypass exhaust pipe 6 are provided in the bypass exhaust pipe 6. It is provided at the branch. In other words, the thermostat valve 7 is configured such that the valve opening degree of the cooling water exiting the waste heat recovery unit 22 is such that the temperature of the cooling water exiting the waste heat recovery unit 22 does not exceed a predetermined temperature (for example, boiling temperature 120 ° C.). Adjusted based on temperature.

  The heat exchanger 36, the thermostat valve 7, and the waste heat recovery unit 22 are integrated as a waste heat recovery unit 23, and are arranged in the middle of the exhaust pipe under the floor at the approximate center in the vehicle width direction. The thermostat valve 7 may be a relatively simple temperature-sensitive valve using bimetal or the like, or may be a control valve controlled by a controller to which a temperature sensor output is input. Adjustment of the amount of heat exchange from the exhaust gas to the cooling water by the thermostat valve 7 involves a relatively large delay. Therefore, if the thermostat valve 7 is adjusted alone, it is difficult to prevent the engine water temperature from exceeding the allowable temperature. However, since the control valve 26 of the second bypass cooling water passage 25 is controlled based on the engine water temperature (exit temperature), the heat recovery amount can be quickly reduced and the engine water temperature can be surely exceeded the allowable temperature. Can be prevented. Further, if the engine water temperature has a margin before the allowable temperature, heat exchange is performed until the temperature of the cooling water exiting the waste heat recovery unit 22 becomes high enough to exceed the allowable temperature of the engine water temperature (for example, 110 to 115 ° C.). To increase the amount of recovered waste heat. The cooling water that has exited the cooling water passage 36 b is joined to the first bypass cooling water passage 24 via the second bypass cooling water passage 25.

  If the temperature of the cooling water from the bypass cooling water passage 14 toward the thermostat valve 15 is sufficiently lowered by exchanging heat with the refrigerant of the Rankine cycle 31 by the heat exchanger 36, for example, the cooling water passage 13 side of the thermostat valve 15 The amount of cooling water passing through the radiator 11 is relatively reduced. Conversely, when the temperature of the cooling water from the bypass cooling water passage 14 toward the thermostat valve 15 becomes high due to the Rankine cycle 31 not being operated, the valve opening of the thermostat valve 15 on the cooling water passage 13 side is increased. The amount of cooling water passing through the radiator 11 is relatively increased. Based on the 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, Rankine cycle 31 will be described. Here, Rankine cycle 31 is not a simple Rankine cycle, but is configured as a part of integrated cycle 30 integrated with refrigeration cycle 51. Hereinafter, the basic Rankine cycle 31 will be described first, and then the refrigeration cycle 51 will be referred to.

  The Rankine cycle 31 is a system that recovers waste heat of the engine 2 to a refrigerant through cooling water of the engine 2 and regenerates the recovered waste heat as power. The Rankine cycle 31 includes a refrigerant pump 32, a heat exchanger 36 as a superheater, an expander 37, and a condenser (condenser) 38, and each component is connected by refrigerant passages 41 to 44 through which a refrigerant (R134a and the like) circulates. Has been. The refrigerant passages 41 to 44 are generally configured by a relatively rigid general metal pipe (steel pipe) that is easy to ensure the sealability of the refrigerant. In this embodiment, the refrigerant passages 41 to 44 are partially flexible. High flexible piping is used, details will be described later.

  The shaft of the refrigerant pump 32 is connected to the output shaft of the expander 37 on the same shaft, and the refrigerant pump 32 is driven by the output (power) generated by the expander 37 and the generated power is used as the output shaft of the engine 2 ( (Refer to FIG. 2A). The shaft of the refrigerant pump 32 and the output shaft of the expander 37 are arranged in parallel with the output shaft of the engine 2, and a belt 34 is hung between the pump pulley 33 provided at the tip of the shaft of the refrigerant pump 32 and the crank pulley 2a. Is turning (see FIG. 1). That is, the output shaft of the expander 37 and the output shaft of the engine 2 are configured to be able to transmit power. Note that a gear-type pump is employed as the refrigerant pump 32 of the present embodiment, and a scroll-type expander is employed as the expander 37 (see FIGS. 2B and 2C). The refrigerant pump 32 and the expander 37 are attached to the engine 2 as shown in FIG.

  Further, an electromagnetic clutch (hereinafter referred to as “expander clutch”) 35 (first clutch) is provided between the pump pulley 33 and the refrigerant pump 32, and the refrigerant pump 32 and the expander 37 are connected to the engine. 2 (see FIG. 2A). Therefore, the expander 37 is connected by connecting the expander clutch 35 when the output generated by the expander 37 exceeds the driving force of the refrigerant pump 32 and the friction of the rotating body (when the predicted expander torque is positive). Rotation of the engine output shaft can be assisted (assisted) by the output generated. Thus, fuel efficiency can be improved by assisting rotation of an engine output shaft using energy obtained by waste heat recovery. Further, the energy for driving the refrigerant pump 32 that circulates the refrigerant can also be covered by the recovered waste heat. The expander clutch 35 may be provided anywhere in the power transmission path from the engine 2 to the refrigerant pump 32 and the expander 37.

  The refrigerant from the refrigerant pump 32 is supplied to the heat exchanger 36 through the refrigerant passage 41. The heat exchanger 36 is a heat exchanger that causes heat exchange between the coolant of the engine 2 and the refrigerant, vaporizes the refrigerant, and superheats the refrigerant.

  The refrigerant from the heat exchanger 36 is supplied to the expander 37 through the refrigerant passage 42. The expander 37 is a steam turbine that converts heat into rotational energy by expanding the vaporized and superheated refrigerant. The power recovered by the expander 37 drives the refrigerant pump 32 and is transmitted to the engine 2 via the belt transmission mechanism to assist the rotation of the engine 2.

  The refrigerant from the expander 37 is supplied to the condenser 38 via the refrigerant passages 43a and 43b. The condenser 38 is a heat exchanger that causes heat exchange between the outside air and the refrigerant to cool and liquefy the refrigerant. For this reason, the condenser 38 is arranged in parallel with the radiator 11 and is cooled by the radiator fan 12. The condenser 38 is attached to the vehicle body.

  The refrigerant passage 43 a is connected to the expander 37. The refrigerant passage 43b connects the refrigerant passage 43a and the condenser 38. The refrigerant passage 43a and the refrigerant passage 43b are connected at a refrigeration cycle junction 46 described later.

  The refrigerant passage 43a that connects the engine 2 side part and the vehicle body side part is a refrigerant flexible pipe that is more flexible than the refrigerant passage 43b in order to absorb relative displacement caused by vibration. High flexibility means low rigidity and deformation. In order to provide flexibility, the flexible pipe is a bellows-like shape, or uses a soft and excellent material as a material. Therefore, the refrigerant passage 43a can bend the middle part freely, and can absorb the vibration when the vibration is transmitted. A portion of the refrigerant passage 43 a on the side of the expander 37 attached to the engine 2 vibrates together with the engine 2 and the expander 37.

  The refrigerant passage 43b is connected to the condenser 38 and is less flexible than the refrigerant passage 43a, that is, has high rigidity, for example, stainless steel pipe or aluminum pipe. The refrigerant passage 43b vibrates together with the condenser 38 attached to the vehicle body.

  The refrigerant passage 43 a is connected to the expander 37 attached to the engine 2. The refrigerant passage 43b is connected to a condenser 38 attached to the vehicle body. Therefore, when the vehicle is driven, the frequency of the refrigerant passage 43a is different from the frequency of the refrigerant passage 43b. In the present embodiment, the refrigerant passage 43a is a flexible pipe for refrigerant, so that the refrigerant passage 43a absorbs the vibration difference between the engine 2 side portion of the refrigerant passage 43a and the refrigerant passage 43b.

  The refrigerant liquefied by the condenser 38 is returned to the refrigerant pump 32 via the refrigerant passages 44a and 44b. The refrigerant returned to the refrigerant pump 32 is sent again to the heat exchanger 36 by the refrigerant pump 32 and circulates through each component of the Rankine cycle 31.

  The refrigerant passage 44 a is connected to the condenser 38. The refrigerant passage 44b connects the refrigerant passage 43a and the refrigerant pump 32. The refrigerant passage 44a and the refrigerant passage 44b are connected at a refrigeration cycle branch point 45 described later.

  The refrigerant passage 44a is less flexible than the refrigerant passage 44b, for example, a stainless steel pipe or an aluminum pipe. The refrigerant passage 44a vibrates together with the condenser 38.

  The refrigerant passage 44b that connects the engine 2 side part and the vehicle body side part is a refrigerant flexible pipe that is more flexible than the refrigerant passage 44a in order to absorb relative displacement due to vibration. The vibration of the engine 2 is transmitted to the portion of the refrigerant passage 44b on the engine 2 side and vibrates together with the engine 2.

  By using the refrigerant passage 44b as the refrigerant flexible pipe, the vibration difference between the refrigerant passage 44a and the refrigerant passage 44b can be absorbed by the refrigerant passage 44b.

  Next, the refrigeration cycle 51 will be described. Since the refrigerating cycle 51 shares the refrigerant circulating through the Rankine cycle 31, it is integrated with the Rankine cycle 31, and the configuration of the refrigerating cycle 51 itself is simplified. That is, the refrigeration cycle 51 includes a compressor (compressor) 52, a condenser 38, and an evaporator (evaporator) 55.

  The compressor 52 is a fluid machine that compresses the refrigerant of the refrigeration cycle 51 to a high temperature and a high pressure. The compressor 52 is attached to the vehicle body. The compressor 52 is an electric compressor and is supplied with electric power from a battery (not shown).

  The refrigerant from the compressor 52 joins the refrigerant passage 43a at the refrigeration cycle junction 46 through the refrigerant passage 56, and then is supplied to the condenser 38 through the refrigerant passage 43b. The refrigerant passage 56 is configured by a general metal pipe (steel pipe) having relatively high rigidity. The condenser 38 is a heat exchanger that condenses and liquefies the refrigerant by heat exchange with the outside air. The liquid refrigerant from the condenser 38 is supplied to an evaporator (evaporator) 55 through a refrigerant passage 57 branched from the refrigerant passage 44a at the refrigeration cycle branching point 45. The refrigerant passage 57 is also composed of a general metal pipe (steel pipe) having relatively high rigidity. The evaporator 55 is disposed in the case of the air conditioner unit in the same manner as a heater core (not shown). The evaporator 55 is a heat exchanger that evaporates the liquid refrigerant from the condenser 38 and cools the conditioned air from the blower fan by the latent heat of evaporation at that time.

  The refrigerant evaporated by the evaporator 55 is returned to the compressor 52 through the refrigerant passage 58. Note that the mixing ratio of the conditioned air cooled by the evaporator 55 and the conditioned air heated by the heater core is adjusted to a temperature set by the occupant according to the opening of the air mix door.

  In the integrated cycle 30 including the Rankine cycle 31 and the refrigeration cycle 51, various valves are appropriately provided in the middle of the circuit in order to control the refrigerant flowing in the cycle. For example, in order to control the refrigerant circulating in the Rankine cycle 31, a refrigerant passage connecting the pump upstream valve 61, the heat exchanger 36 and the expander 37 to a refrigerant passage 44b connecting the refrigeration cycle branch point 45 and the refrigerant pump 32. 42 is provided with an expander upstream valve 62. The refrigerant passage 41 that connects the refrigerant pump 32 and the heat exchanger 36 is provided with a check valve 63 to prevent the refrigerant from flowing backward from the heat exchanger 36 to the refrigerant pump 32. The refrigerant passage 43 a that connects the expander 37 and the refrigeration cycle merge point 46 is also provided with a check valve 64 to prevent the refrigerant from flowing back from the refrigeration cycle merge point 46 to the expander 37. Further, an expander bypass passage 65 that bypasses the expander 37 from the upstream of the expander upstream valve 62 and merges upstream of the check valve 64 is provided, and a bypass valve 66 is provided in the expander bypass passage 65. Further, a pressure regulating valve 68 is provided in a passage 67 that bypasses the bypass valve 66. Also on the refrigeration cycle 51 side, an air conditioner circuit valve 69 is provided in the refrigerant passage 57 that connects the refrigeration cycle branch point 45 and the evaporator 55.

  The four valves 61, 62, 66, and 69 are all electromagnetic on-off valves. An expander upstream pressure signal detected by the pressure sensor 72, a refrigerant pressure Pd signal at the outlet of the condenser 38 detected by the pressure sensor 73, a rotation speed signal of the expander 37, and the like are input to the engine controller 71. . The engine controller 71 controls the compressor 52 of the refrigeration cycle 51 and the radiator fan 12 based on these input signals in accordance with predetermined operating conditions, and also controls the four electromagnetic on-off valves 61, 62, 66. , 69 is controlled.

  For example, the expander torque (regenerative power) is predicted based on the expander upstream pressure detected by the pressure sensor 72 and the expander rotational speed, and when the predicted expander torque is positive (assist rotation of the engine output shaft). The expander clutch 35 is engaged, and when the predicted expander torque is zero or negative, the expander clutch 35 is released. Based on the sensor detection pressure and expander rotational speed, the expander torque can be predicted with higher accuracy than when the expander torque (regenerative power) is predicted from the exhaust temperature. Accordingly, the expander clutch 35 can be appropriately engaged / released (refer to Japanese Unexamined Patent Application Publication No. 2010-190185 for details).

  The four on-off valves 61, 62, 66, 69 and the two check valves 63, 64 are refrigerant valves. The functions of these refrigerant valves are shown again in FIG.

  In FIG. 3, the pump upstream valve 61 closes under a predetermined condition in which the refrigerant tends to be biased to the circuit of the Rankine cycle 31 as compared with the circuit of the refrigeration cycle 51, such as when the Rankine cycle 31 is stopped. In order to prevent the bias of the lubricating component (including the lubricating component), the circuit of the Rankine cycle 31 is closed in cooperation with the check valve 64 downstream of the expander 37, as will be described later. The expander upstream valve 62 blocks the refrigerant passage 42 when the refrigerant pressure from the heat exchanger 36 is relatively low so that the refrigerant from the heat exchanger 36 can be held until the pressure becomes high. is there. Thereby, even when the expander torque cannot be sufficiently obtained, the heating of the refrigerant is promoted, and for example, the time until the Rankine cycle 31 is restarted (regeneration can actually be performed) can be shortened. The bypass valve 66 is opened so that the refrigerant pump 32 can be operated after the expander 37 is bypassed when the amount of refrigerant existing on the Rankine cycle 31 side is insufficient when the Rankine cycle 31 is started. This is for shortening the startup time of the Rankine cycle 31. By operating the refrigerant pump 32 after the expander 37 is bypassed, the refrigerant temperature at the outlet of the condenser 38 or the inlet of the refrigerant pump 32 has a predetermined temperature difference (subcool degree SC) from the boiling point considering the pressure at that portion. ) If the state lowered as described above is realized, the Rankine cycle 31 is ready to supply a sufficient liquid refrigerant.

  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 adjusting valve 68, and the expander upstream valve 62. When the Rankine cycle regenerative efficiency is low, the Rankine cycle operation is stopped, the circuit is closed over the front and rear sections of the heat exchanger, the refrigerant pressure during the stop is increased, and the high-pressure refrigerant is used. Allow the Rankine cycle to restart quickly. The pressure regulating valve 68 functions as a relief valve that opens when the pressure of the refrigerant supplied to the expander 37 becomes too high and releases the refrigerant that has become too high.

  The check valve 64 downstream of the expander 37 is for preventing the bias of the refrigerant to the Rankine cycle 31 in cooperation with the above-described pump upstream valve 61. If the engine 2 is not warmed immediately after the start of the operation of the hybrid vehicle 1, the Rankine cycle 31 becomes cooler than the refrigeration cycle 51, and the refrigerant may be biased toward the Rankine cycle 31 side. Although the probability of being biased toward the Rankine cycle 31 is not so high, for example, immediately after the start of vehicle operation in summer, the cooling capacity is most demanded in the situation where it is desired to cool the interior quickly, so the slight uneven distribution of refrigerant is also eliminated. Therefore, there is a demand for securing the refrigerant for the refrigeration cycle 51. Therefore, a check valve 64 is provided to prevent uneven distribution of refrigerant to the Rankine cycle 31 side.

  The compressor 52 does not have a structure in which the refrigerant can freely pass when driving is stopped, but can prevent the refrigerant from being biased toward the refrigeration cycle 51 in cooperation with the air conditioner circuit valve 69. This will be described. When the operation of the refrigeration cycle 51 stops, the refrigerant may move from the relatively high temperature Rankine cycle 31 side to the refrigeration cycle 51 side during steady operation, and the refrigerant circulating through the Rankine cycle 31 may be 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 accumulate in the evaporator 55 having a relatively large volume and a low temperature. In this case, the movement of the refrigerant from the condenser 38 to the evaporator 55 is interrupted by stopping the driving of the compressor 52, and the air conditioner circuit valve 69 is closed to prevent the refrigerant from being biased to the refrigeration cycle 51.

  Next, FIG. 5 is a schematic perspective view of the engine 2 showing a package of the entire engine 2. 5 is characterized in that the heat exchanger 36 is arranged vertically above the exhaust manifold 4. That is, the heat exchanger 36 is attached to the engine 2. By placing the heat exchanger 36 in the space vertically above the exhaust manifold 4, the mountability of the Rankine cycle 31 to the engine 2 is improved. The engine 2 is provided with a tension pulley 8.

  Next, a basic operation method of the Rankine cycle 31 will be described with reference to FIGS. 7A and 7B.

  First, FIGS. 7A and 7B are operation region diagrams of the Rankine cycle 31. FIG. FIG. 7A shows the operating range of Rankine cycle 31 when the horizontal axis is the outside air temperature and the vertical axis is the engine water temperature (cooling water temperature). In FIG. 7B, the horizontal axis is the engine speed and the vertical axis is the engine torque (engine The operating range of the Rankine cycle 31 is shown.

  7A and 7B, the Rankine cycle 31 is operated when a predetermined condition is satisfied, and the Rankine cycle 31 is operated when both of these conditions are satisfied. In FIG. 7A, the operation of the Rankine cycle 31 is stopped in a region on the low water temperature side where priority is given to warm-up of the engine 2 and a region on the high outside air temperature side where the load on the compressor 52 increases. During warm-up when the exhaust temperature is low and the recovery efficiency is poor, the Rankine cycle 31 is not operated, so that the coolant temperature is quickly raised. The Rankine cycle 31 is stopped at a high outside air temperature where high cooling capacity is required, and sufficient refrigerant and cooling capacity of the condenser 38 are provided to the refrigeration cycle 51. In FIG. 7B, since the vehicle is a hybrid vehicle, the operation of the Rankine cycle 31 is stopped in the EV traveling region and the region on the high rotational speed side where the friction of the expander 37 increases. Since it is difficult to make the expander 37 have a high-efficiency structure with little friction at all rotation speeds, in the case of FIG. 7B, the expansion is performed so that the friction is small and the efficiency is high in the engine rotation speed range where the operation frequency is high. The machine 37 is configured (the dimensions of each part of the expander 37 are set).

  The effect of 1st Embodiment of this invention is demonstrated.

  FIG. 8 schematically shows a piping state of the integrated cycle 30 of the first embodiment. As described above, the refrigerant pump 32, the heat exchanger 36, and the expander 37 of the Rankine cycle 31 are each attached to the engine 2, and the condenser 38 is attached to the vehicle body side. The refrigerant pump 32 and the heat exchanger 36 and between the heat exchanger 36 and the expander 37 are connected by a relatively rigid general metal pipe (steel pipe) 101, and the expander 37 and the condenser 38 are connected to each other. The condenser 38 and the refrigerant pump 32 are connected by a flexible passage (pipe) including the flexible pipe 100 at least partly along the way. Thereby, the vibration difference (change in relative position) between the expander 37 and the refrigerant pump 32 attached to the engine 2 side and the condenser 38 attached to the vehicle body side is absorbed by the flexible pipe 100, This increases the reliability of the parts or suppresses the transmission of unpleasant vibrations to the occupant.

  In particular, in the present embodiment, not only the refrigerant pump 32 is attached to the engine 2 side so that the engine 2 can drive the refrigerant pump 32, but also the expander 37 is attached to the engine 2 side. The refrigerant pump 32 can be driven also by the regenerative output of the expander 37, the refrigerant pump 32 can be driven by the power of the engine 2, and the degree of freedom of operation of the Rankine cycle 31 is increased. Even if the regenerative output is utilized, the refrigerant pump 32 can be driven to improve the energy efficiency. Under such a premise, since the heat exchanger 36 provided between the refrigerant pump 32 and the expander 37 is attached to the engine 2 side, heat exchange is performed between the refrigerant pump 32 and the heat exchanger 36. The expander 36 and the expander 37 can be connected by a relatively rigid passage (pipe) 101, and only between the expander 37 and the condenser 38, and between the condenser 38 and the refrigerant pump 32. For example, the flexible pipe 100 can be connected with great flexibility. As a result, the number of relatively expensive flexible pipes 100 can be reduced and the cost can be reduced. That is, only two flexible pipes 100 are provided in the circuit of the Rankine cycle 31.

  Specifically, the refrigerant flexible pipe having at least a part of the refrigerant passage 43a connected to the expander 37 attached to the engine 2 having higher flexibility than the refrigerant passage 43b connected to the condenser 38 attached to the vehicle body, To do. Thereby, the vibration difference between the engine 2 side portion of the refrigerant passage 43a and the refrigerant passage 43b can be absorbed by the refrigerant passage 43a. Further, the refrigerant passage 43b can be a metal pipe such as a copper pipe, a stainless steel pipe, and an aluminum pipe, which is cheaper than the refrigerant flexible pipe, and the number of expensive refrigerant flexible pipes can be reduced. Therefore, the cost of the integration cycle 30 can be reduced.

  By using the refrigerant flexible pipe for at least a part of the refrigerant passage 43a, the length of the pipe connecting the expander 37 and the condenser 38 can be shortened, the pressure loss in the pipe can be reduced, and integrated. The efficiency of the cycle 30 can be improved.

  At least a part of the refrigerant passage 44b connected to the refrigerant pump 32 attached to the engine 2 is a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 44a connected to the condenser 38. Thereby, the difference in vibration between the refrigerant passage 44a and the portion of the refrigerant passage 44b on the engine 2 side can be absorbed by the refrigerant passage 44b. In addition, the refrigerant passage 44a can be a metal pipe that is cheaper than the refrigerant flexible pipe, and the number of expensive refrigerant flexible pipes can be reduced. Therefore, the cost of the integration cycle 30 can be reduced.

  By using the refrigerant flexible pipe for at least a part of the refrigerant passage 43a, the length of the pipe connecting the condenser 38 and the refrigerant pump 32 can be shortened, the pressure loss in the pipe can be reduced, and integration is performed. The efficiency of the cycle 30 can be improved.

  In the integrated cycle 30 configured to transmit power between the output shaft of the expander 37 and the output shaft of the engine 2, the refrigerant passage 43a is a flexible pipe for refrigerant, and the refrigerant passage 43b is a metal pipe, for example. Can get more.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 9 is a schematic configuration diagram of a hybrid vehicle in the present embodiment. FIG. 10 is a schematic configuration diagram of an integration cycle in the present embodiment. The second embodiment will be described with a focus on differences from the first embodiment. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted here.

  The compressor 59 is attached to the engine 2 and is driven by the engine 2. As shown in FIG. 9, a compressor pulley 53 is fixed to the drive shaft of the compressor 59, and a belt 34 is wound around the compressor pulley 53 and the crank pulley 2a. The driving force of the engine 2 is transmitted to the compressor pulley 53 via the belt 34, and the compressor 59 is driven. In addition, an electromagnetic clutch 54 is provided between the compressor pulley 53 and the compressor 59 so that the compressor 59 and the compressor pulley 53 can be connected and disconnected.

  The refrigerant passage 56 connected to the compressor 59 is a refrigerant flexible pipe having greater flexibility than the refrigerant passage 43b.

  The refrigerant passage 58 provided between the compressor 59 and the evaporator 55 and connected to the compressor 59 is a refrigerant flexible pipe, like the refrigerant passage 56.

  When the compressor 59 is attached to the engine 2, the frequency of the refrigerant passage 56 connected to the compressor 59 is different from the frequency of the refrigerant passage 43 b connected to the condenser 38 when the vehicle is driven. In the present embodiment, the refrigerant passage 56 is a flexible pipe for refrigerant, so that the vibration difference between the refrigerant passage 56 and the refrigerant passage 43 b is absorbed by the refrigerant passage 56.

  The effect of 2nd Embodiment of this invention is demonstrated.

  FIG. 11 schematically shows the piping state of the integration cycle 30 of the second embodiment. The difference from the first embodiment is that since the compressor 59 is attached to the engine 2 side, the refrigerant passage before and after the compressor 59 is constituted by the flexible pipe 100. Also according to the second embodiment, the number of relatively expensive flexible pipes 100 can be reduced and the cost can be suppressed. That is, only two flexible pipes 100 are provided in the circuit of the Rankine cycle 31, and the number of the flexible pipes 100 is suppressed to four when viewed in the integrated cycle 30 as a whole.

  Specifically, at least a part of the refrigerant passage 56 is a refrigerant flexible pipe, and the refrigerant passage 56 is connected to the refrigerant passage 43 b at the refrigeration cycle junction 46. Thereby, the vibration difference between the refrigerant passage 43b and the refrigerant passage 56 can be absorbed by the refrigerant passage 43b.

  Next, a third embodiment of the present invention will be described.

  The third embodiment will be described with a focus on differences from the second embodiment.

  In the third embodiment, the refrigerant passage 43 b is a flexible pipe that is more flexible than the refrigerant passage 43 a and the refrigerant passage 56. Further, the refrigerant passage 43a and the refrigerant passage 56 are made of, for example, stainless steel pipe or aluminum pipe having low flexibility.

  The effect of the third embodiment of the present invention will be described.

  FIG. 12 schematically shows the piping state of the integration cycle 30 of the third embodiment. The difference from the second embodiment is that the pipe connecting the expander 37 and the condenser 38 and the pipe connecting the compressor 59 and the condenser 38 are joined together on the way, and the part after joining is a flexible pipe. 100. Also according to the third embodiment, the number of relatively expensive flexible pipes 100 can be reduced and the cost can be suppressed. That is, only two flexible pipes 100 are provided in the circuit of the Rankine cycle 31, and the number of the flexible pipes 100 is suppressed to three when viewed in the integrated cycle 30 as a whole.

  Specifically, the refrigerant passage 43b connected to the condenser 38 is a refrigerant flexible pipe, and the refrigerant passage 43a connected to the expander 37 and the refrigerant passage 56 connected to the compressor 59 are less expensive than the refrigerant flexible pipe. For example, stainless steel pipes and aluminum pipes are used. Thereby, the vibration difference between the refrigerant passage 43b and the refrigerant passage 43a and the refrigerant passage 56 can be absorbed. Moreover, the refrigerant passage 43a and the refrigerant passage 56 can be made into inexpensive piping, and the cost of the integrated cycle 30 can be reduced.

  The refrigerant passage 44a may be a flexible pipe for refrigerant, and the refrigerant passage 44b may be a stainless steel pipe, an aluminum pipe, or the like.

  By using the refrigerant flexible pipe for at least a part of the refrigerant passage, the length of the pipe connecting the expander 37 and the compressor 59 and the condenser 38 and the pipe connecting the condenser 38 and the refrigerant pump 32 are shortened. The pressure loss in the piping can be reduced, and the efficiency of the integrated cycle 30 can be improved.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea. For example, as a flexible passage pipe for absorbing relative displacement due to vibration, a part of a general metal pipe including a flexible pipe for refrigerant having high flexibility (in the middle) is adopted. Of course it is also good.

2 Engine 30 Integrated cycle (Rankine cycle system)
32 Refrigerant pump 36 Heat exchanger 37 Expander 38 Condenser 43a Refrigerant passage (first pipe)
43b Refrigerant passage (third piping)
44a Refrigerant passage (sixth pipe)
44b Refrigerant passage (4th piping)
51 Refrigeration cycle 52 Compressor 56 Refrigerant passage (second pipe)
57 Refrigerant passage (fifth pipe)

Claims (9)

A refrigerant pump attached to the engine and delivering refrigerant;
A heat exchanger attached to the engine for recovering waste heat of the engine into the refrigerant;
An expander that is attached to the engine and converts the waste heat recovered by the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger;
In a Rankine cycle system comprising a condenser attached to a vehicle body and condensing the refrigerant expanded by the expander,
A Rankine cycle system characterized in that a connection between the expander and the condenser and between the condenser and the refrigerant pump are connected by flexible piping that is more flexible than others. A refrigeration cycle sharing the condenser and the refrigerant;
A compressor provided in the refrigeration cycle is attached to the engine, and a pipe between the expander and the condenser and a pipe between the compressor and the condenser are joined together while being supported on the engine side. The Rankine cycle system according to claim 1, wherein the junction and the condenser are connected by a flexible pipe.   The Rankine cycle system according to claim 1, wherein an output shaft of the expander and an engine output shaft are configured to be capable of transmitting power. A heat exchanger attached to the engine and recovering the waste heat of the engine into a refrigerant;
An expander that is attached to the engine and converts the waste heat recovered by the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger;
A condenser attached to a vehicle body for condensing the refrigerant expanded by the expander;
In the Rankine cycle system comprising the condenser and the refrigeration cycle of the air conditioner that shares the refrigerant,
A first pipe connected to the expander;
A first pipe connected to the second pipe connected to the compressor of the refrigeration cycle, and a third pipe for introducing the refrigerant into the condenser;
The Rankine cycle system according to any one of the first piping and the third piping, wherein the piping has higher flexibility than the other piping. The compressor is attached to the vehicle body,
The Rankine cycle system according to claim 4, wherein the first pipe is more flexible than the second pipe and the third pipe. The compressor is attached to the engine;
The Rankine cycle system according to claim 4, wherein the first pipe and the second pipe are more flexible than the third pipe. The compressor is attached to the engine;
The Rankine cycle system according to claim 4, wherein the third pipe is more flexible than the first pipe and the second pipe. A refrigerant pump for supplying the refrigerant condensed by the condenser to the heat exchanger;
A fourth pipe connected to the refrigerant pump;
A fourth pipe connected to the fourth pipe and a fifth pipe connected to the evaporator of the refrigeration cycle, and a sixth pipe through which the refrigerant discharged from the condenser flows;
The Rankine cycle system according to any one of claims 4 to 7, wherein any one of the fourth pipe and the sixth pipe has higher flexibility than the other pipe.   The Rankine cycle system according to any one of claims 4 to 8, wherein the output shaft of the expander and the output shaft of the engine can transmit power.

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