JP2014238007A - Rankine cycle system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Rankine cycle system for heating engine coolant.SOLUTION: A Rankine cycle system 30 comprises: a Rankine cycle 31 that includes a refrigerant pump 32 circulating refrigerant, a heat exchanger 36 recovering waste heat of an engine 2 to refrigerant, an expansion machine 37 converting the waste heat recovered to the refrigerant to power by expanding the refrigerant, and a condenser 38 condensing the refrigerant expanded by the expansion machine 37; and a refrigeration cycle 51 that includes a compressor 52 circulating the refrigerant and an evaporator 55 evaporating the refrigerant, and that uses the condenser 38 and the refrigerant commonly to the Rankine cycle 31. If the engine 2 starts from a cold state, the compressor 52 is driven, and the evaporator 55 absorbs heat to heat the refrigerant in the refrigeration cycle 51. If the engine 2 starts from the cold state, the heat exchanger 36 warms coolant of the engine 2 by heat of the refrigerant absorbed by the evaporator 55 in the Rankine cycle 31.

Description

  The present invention relates to a Rankine cycle system.

  Conventionally, Patent Document 1 discloses that a hot gas refrigerant circuit is replenished with a refrigerant in a condenser in order to improve a heating function.

Japanese Patent Laid-Open No. 5-272817

  However, in the above invention, when the temperature of the engine cooling water is low, the point of warming the engine cooling water is not considered, and when the temperature of the engine cooling water is low, the refrigerant in the condenser is used. There is a problem that the engine coolant cannot be heated.

  The present invention has been invented to solve such problems, and aims to warm engine cooling water with a refrigerant in a refrigeration cycle.

  A Rankine cycle system according to an aspect of the present invention uses a refrigerant pump that circulates a refrigerant, a heat exchanger that recovers engine waste heat into the refrigerant, and waste heat recovered by the refrigerant by expanding the refrigerant. A refrigeration cycle having a Rankine cycle including an expander for conversion, a condenser for condensing the refrigerant expanded by the expander, a compressor for circulating the refrigerant, and an evaporator for evaporating the refrigerant, and sharing the condenser and the refrigerant Is a Rankine cycle system. When the engine starts from a cold state, the refrigeration cycle drives the compressor and absorbs heat by the evaporator to heat the refrigerant. In the Rankine cycle, when the engine starts from a cold state, the coolant of the engine is warmed by the heat exchanger by the refrigerant that has absorbed heat by the evaporator.

  According to this aspect, when the engine is started from a cold state, the cooling water of the engine can be warmed by the refrigerant of the refrigeration cycle by driving the compressor of the refrigeration cycle.

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 a schematic block diagram of the integration cycle of 2nd Embodiment of this invention. It is a schematic block diagram of the integration cycle of 3rd Embodiment of this invention.

  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.

  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. Further, a part of the cooling water flowing through the cooling water passage 13 flows into the cooling water passage 27 passing through the heater core 28. The cooling water passage 27 is provided with a cooling water valve 29 that is an electromagnetic valve. The cooling water that has passed through the heater core 28 merges with the cooling water that has passed through the radiator 11 downstream of 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 of the Rankine cycle 31 flows so that heat can be exchanged between the refrigerant and the cooling water is a cooling water passage 36a, 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 and knocking, for example. 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 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). That is, 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 the belt 34 is provided between the pump pulley 33 provided at the tip of the shaft of the refrigerant pump 32 and the crank pulley 2a. (See FIG. 1). 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).

  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 passage 43. 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 refrigerant liquefied by the condenser 38 is returned to the refrigerant pump 32 via the refrigerant passage 44. 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.

  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, and is driven by the engine 2. That is, as shown in FIG. 4, the compressor pulley 53 is fixed to the drive shaft of the compressor 52, and the 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 52 is driven. An electromagnetic clutch (hereinafter referred to as “compressor clutch”) 54 (second clutch) is provided between the compressor pulley 53 and the compressor 52 so that the compressor 52 and the compressor pulley 53 can be connected and disconnected. ing.

  Returning to FIG. 1, the refrigerant from the compressor 52 joins the refrigerant passage 43 via the refrigerant passage 56 and is then supplied to the condenser 38. 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 44. The evaporator 55 is disposed in the case of the air conditioner unit, similarly to the heater core 28. 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. The conditioned air cooled by the evaporator 55 and the conditioned air heated by the heater core 28 are adjusted to a temperature set by the occupant by changing the mixing ratio 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, the refrigerant passage 44 that connects the pump upstream valve 61, the heat exchanger 36, and the expander 37 to the refrigerant passage 44 that connects the refrigeration cycle branch point 45 and the refrigerant pump 32. 42 is provided with an expander upstream valve 62. The refrigerant passage 43 that connects the expander 37 and the refrigeration cycle junction 46 is provided with a check valve 64 to prevent the refrigerant from flowing back from the refrigeration cycle junction 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 downstream 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. A cooling water valve 29 is provided in the cooling water passage 27.

  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 check valve 64 are refrigerant valves. The functions of these refrigerant valves are shown again in FIG.

  In FIG. 3, the pump upstream valve 61 is provided at the inlet of the refrigerant pump 32, and the pump upstream valve 61 tends to bias the refrigerant in the circuit of the Rankine cycle 31 compared to the circuit of the refrigeration cycle 51, such as when the Rankine cycle 31 is stopped. In order to prevent the refrigerant (including the lubricating component) from being biased to the Rankine cycle 31 by closing under a predetermined condition, the Rankine cooperates with the check valve 64 downstream of the expander 37 as described later. The circuit of cycle 31 is closed. 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 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.

  On the other hand, the cooling water valve 29 is a cooling water system valve. The opening degree of the cooling water valve 29 is controlled by the engine controller 71 in response to a passenger's heating or temperature control request.

  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. 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. Note that not operating the Rankine cycle 31 (stopping operation) includes a state in which the refrigerant flows in a direction opposite to the direction of refrigerant flow when the Rankine cycle 31 is operated. 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).

  Next, the operation of this embodiment will be described.

  When the engine 2 is started from a cold state where the temperature of the coolant of the engine 2 is low and the temperature of the cooling water of the engine 2 is low, the compressor 52 is driven without operating the Rankine cycle 31 after the engine 2 is started. When the compressor 52 is driven, the refrigerant absorbs heat by the evaporator 55 and further absorbs heat generated when the engine 52 is driven by the engine 2 to increase the temperature. The refrigerant whose temperature has increased flows in the Rankine cycle 31 in which the refrigerant pump 32 is stopped, in the direction opposite to that during the operation of the Rankine cycle 31, and warms the cooling water of the engine 2 by the heat exchanger 36. Specifically, the refrigerant flows into the heat exchanger 36 through the refrigerant passage 56, the refrigerant passage 43, the expander bypass passage 65, and the refrigerant passage 42. The heat of the refrigerant is transmitted to the cooling water by the heat exchanger 36, and the temperature of the cooling water increases. The refrigerant whose temperature has been lowered due to heat transfer to the cooling water is discharged from the heat exchanger 36, passes through the refrigerant passage 41, the refrigerant pump 32, the refrigerant passage 44, the refrigerant passage 57, the evaporator 55, and the refrigerant passage 58, and is then supplied to the compressor 52. Flow into. In this way, the refrigerant circulates through the refrigeration cycle 51 and the Rankine cycle 31. The expander clutch 35 is released.

  Further, when the engine 2 is started from the cold state and there is a request for heating or temperature control by the occupant, the temperature of the passenger compartment is adjusted by the inside air circulation mode, and the cooling water of the engine 2 is warmed. The inside air circulation mode is a mode in which air in the passenger compartment is circulated. When the compressor 52 is driven, the air temperature around the evaporator 55 decreases due to heat absorption by the evaporator 55, but the heater core 28 warms the air around the evaporator 55, thereby satisfying the heating or temperature control request by the occupant. Warm the 2 cooling water.

  When the engine 2 is started from a cold state, the coolant of the engine 2 is warmed up by the refrigerant even during deceleration such as immediately after the vehicle starts. Even when the vehicle is decelerating, the compressor clutch 54 is engaged and the compressor 52 is driven. Therefore, even when the vehicle is decelerating, the refrigerant is circulated to the Rankine cycle 31 by the compressor 52 and the cooling water of the engine 2 is warmed by the heat exchanger 36.

  The effect of this embodiment will be described.

  When starting the engine 2 from the cold state, the compressor 52 of the refrigeration cycle 51 is driven without operating the Rankine cycle 31. Thereby, the cooling water of the engine 2 can be warmed by the refrigerant in the heat exchanger 36 by the heat absorption by the evaporator 55 of the refrigeration cycle 51 and the heat given by the work of the compressor 52. That is, the cooling water is effectively increased by exchanging heat with the refrigerant warmed by both the heat (vaporization latent heat) received from the passenger compartment air by the evaporator 55 and the heat generated by driving the compressor 52. Warm up. In addition, by sharing the refrigerant in the Rankine cycle 31 and the refrigeration cycle 51, the cooling water of the engine 2 can be warmed by the refrigerant without adding a new heat exchanger or circuit. Therefore, by warming the cooling water of the engine 2 by the heat recoverable by the integrated system 30, the cooling water of the engine 2 can be quickly warmed without using a new warm-up means for warming the cooling water of the engine 2. it can.

  When the cooling water of the engine 2 is warmed by the refrigerant and the heating or temperature control is requested by the occupant, the outside air introduction mode (inside the outside is taken in) by adjusting the temperature inside the vehicle compartment by the inside air circulation mode. The ventilation loss can be reduced as compared with the case where the temperature is adjusted by a mode in which air is heated. In the outside air introduction mode, the air inside the vehicle interior is ventilated to the outside of the vehicle interior, so that the window glass is less likely to fog up due to condensation. However, the heater core 28 needs to heat a lot of air, and the vehicle interior heating requires a lot of heat. Is taken away and cooling water is hard to warm up. As a result, it may take time not only to warm up the engine 2 but also to warm the passenger compartment. On the other hand, in the inside air circulation mode, it is not necessary to warm the ventilation portion, so that the temperature of the cooling water can be effectively increased, and the humidity of the passenger compartment air is reduced by the evaporator 55, so that the window due to condensation is reduced. Glass is less likely to fog up. That is, even if the same energy as that in the outside air introduction mode is supplied, the temperature of the cooling water is further increased, and both the warming up of the engine 2 and the warming of the passenger compartment are quickly achieved. Can be suppressed. Even when there is no request for heating by the occupant, the temperature of the passenger compartment air is heated by the heater core 28 as much as the temperature of the passenger compartment air is reduced by the evaporator 55, so that the temperature of the passenger compartment air is not excessively lowered. You can also.

  The cooling water of the engine 2 can be warmed by using a part of the deceleration energy of the vehicle even at a low temperature when the regenerative energy cannot be stored in the hybrid vehicle, and the deceleration energy of the vehicle can be utilized.

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

  FIG. 8 is a schematic configuration diagram showing the entire system of the Rankine cycle 31 of the second embodiment. Here, a different part from 1st Embodiment is demonstrated. In the present embodiment, a condenser valve 47 that is an electromagnetic valve is provided between the refrigeration cycle branch point 45 and the condenser 38.

  The opening and closing of the condenser valve 47 is controlled by the engine controller 71. When the Rankine cycle 31 is operated, the condenser valve 47 is opened, and when starting the engine 2 from the cold state, the condenser valve 47 is closed.

  The effect of this embodiment will be described.

  When the engine 2 is started from the cold state, the refrigerant valve is prevented from flowing into the condenser 38 by closing the condenser valve 47, and the entire flow rate of the refrigerant can be introduced into the heat exchanger 36. Thus, the cooling water of the engine 2 can be efficiently warmed.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  FIG. 9: has shown the schematic block diagram showing the whole system of Rankine cycle 31 of 3rd Embodiment. Here, a different part from 2nd Embodiment is demonstrated. In this embodiment, the Rankine cycle 31 includes a bypass passage 39 that bypasses the refrigerant pump 32 and a pump bypass valve 63 provided in the bypass passage 39.

  The opening and closing of the pump bypass valve 63 is controlled by the engine controller 71. The pump bypass valve 63 is closed during operation of the Rankine cycle 31, and the pump bypass valve 63 is opened when the engine 2 is started from a cold state.

  The effect of this embodiment will be described.

  When the engine 2 is started from a cold state, the refrigerant can be prevented from flowing to the refrigerant pump 32 by opening the pump bypass valve 63, and pressure loss can be reduced.

  The pump bypass valve 63 may be provided between the junction of the bypass passage 39 and the refrigerant passage 41 and the refrigerant pump 32. In this case, the pump bypass valve 63 is opened during operation of the Rankine cycle 31, and the pump bypass valve 63 is closed when the engine 2 is started from the cold state. Further, a valve is provided between the bypass passage 39 and the junction of the bypass passage 39 and the refrigerant passage 41 and the refrigerant pump 32. During operation of the Rankine cycle 31, the refrigerant is allowed to flow only through the refrigerant pump 32, and the engine 2 is started from the cold state. When starting, the refrigerant may flow only in the bypass passage 39. By these, when starting the engine 2 from a cold state, it can suppress that a refrigerant | coolant flows into the refrigerant | coolant pump 32, and can further reduce pressure loss.

  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.

2 Engine 28 Heater core (temperature control means)
30 Integrated cycle (Rankine cycle system)
32 refrigerant pump 36 heat exchanger 37 expander 38 condenser 39 bypass passage 47 condenser valve (inflow prevention means)
51 Refrigeration cycle 52 Compressor 63 Pump bypass valve (inflow means)

Claims (5)

A refrigerant pump that circulates the refrigerant; a heat exchanger that recovers waste heat of the engine to the refrigerant; an expander that converts the waste heat recovered by the refrigerant into power by expanding the refrigerant; and the expander A Rankine cycle comprising a condenser for condensing the refrigerant expanded by
A Rankine cycle system comprising a compressor that circulates the refrigerant and an evaporator that evaporates the refrigerant, and a refrigeration cycle that shares the condenser and the refrigerant,
The refrigeration cycle is
When the engine starts from a cold state, the compressor is driven, the refrigerant absorbs heat to heat the refrigerant,
The Rankine cycle is
When the engine is started from the cold state, the coolant of the engine is warmed by the heat exchanger by the refrigerant that has absorbed heat by the evaporator.   The Rankine cycle system according to claim 1, further comprising an inflow prevention unit configured to prevent the refrigerant from flowing into the condenser when the engine is started from the cold state and the compressor is driven. . A bypass passage for bypassing the refrigerant pump;
The Rankine cycle system according to claim 1, further comprising an inflow unit that causes the refrigerant to flow into the bypass passage when the engine starts from the cold state. The refrigeration cycle includes a temperature control means for warming the air in the passenger compartment of a vehicle equipped with a Rankine cycle system,
The temperature control means warms the air in an inside air circulation mode when the engine is started from the cold state and there is a warm-up or temperature control request for the passenger compartment. The Rankine cycle system according to any one of the above.   The Rankine cycle system according to any one of claims 1 to 4, wherein the compressor is driven by transmission of rotation of the engine.

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