US20140174087A1 - Rankine cycle system - Google Patents
Rankine cycle system Download PDFInfo
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- US20140174087A1 US20140174087A1 US14/233,204 US201214233204A US2014174087A1 US 20140174087 A1 US20140174087 A1 US 20140174087A1 US 201214233204 A US201214233204 A US 201214233204A US 2014174087 A1 US2014174087 A1 US 2014174087A1
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- Prior art keywords
- refrigerant
- engine
- expander
- condenser
- pipe
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
- F01K7/16—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
- F01K23/101—Regulating means specially adapted therefor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/12—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled
- F01K23/14—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled including at least one combustion engine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
- F01K25/10—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours the vapours being cold, e.g. ammonia, carbon dioxide, ether
Definitions
- the present invention relates to a Rankine cycle system.
- JP2001-182504A mount an evaporator and an expander on an engine in an on-vehicle Rankine cycle system.
- the evaporator and the expander are connected to another member, e.g. a condenser mounted on a vehicle body via pipes. Since a member mounted on an engine and a member mounted on the vehicle body differ in vibration frequency, the member mounted on the engine and that mounted on the vehicle body are connected by a flexible pipe. Since flexible pipes are more expensive than pipes having high rigidity such as stainless steel pipes and aluminum pipes, the usage thereof is preferably reduced.
- the present invention was developed to solve the above problem and aims to reduce the cost of a Rankine cycle system by reducing the usage of flexible pipes.
- a Rankine cycle system includes a refrigerant pump which is mounted on an engine and is configured to feed refrigerant, a heat exchanger which is mounted on the engine and is configured to recover exhaust heat of the engine to the refrigerant, an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger, and a condenser which is mounted on a vehicle body and is configured to condense the refrigerant expanded by the expander.
- the expander and the condenser, and the condenser and the refrigerant pump are connected by flexible pipes having higher flexibility than other pipes.
- FIG. 1 is a schematic configuration diagram of an integrated cycle of a first embodiment of the present invention
- FIG. 2A is a schematic sectional view of an expander pump formed by integrating a pump and an expander
- FIG. 2B is a schematic sectional view of a refrigerant pump
- FIG. 2C is a schematic sectional view of an expander
- FIG. 3 is a schematic diagram showing functions of refrigeration system valves
- FIG. 4 is a schematic configuration diagram of a hybrid vehicle
- FIG. 5 is a schematic perspective view of an engine
- FIG. 6 is a schematic diagram showing an arrangement of an exhaust pipe when the vehicle is viewed from below
- FIG. 7A is a characteristic graph of a Rankine cycle operating region
- FIG. 7B is a characteristic graph of a Rankine cycle operating region
- FIG. 8 is a view diagrammatically showing a state of pipes of the integrated cycle of the first embodiment
- FIG. 9 is a schematic configuration diagram of a hybrid vehicle of a second embodiment of the present invention.
- FIG. 10 is a schematic configuration diagram of an integrated cycle of the second embodiment of the present invention.
- FIG. 11 is a view diagrammatically showing a state of pipes of the integrated cycle of the second embodiment.
- FIG. 12 is a view diagrammatically showing a state of pipes of an integrated cycle of a third embodiment.
- FIG. 1 is a schematic configuration diagram showing an 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 refrigerant and a condenser 38 with a refrigeration cycle 51 and a Rankine cycle system obtained by integrating the Rankine cycle 31 and the refrigeration cycle 51 is referred to as an integrated cycle 30 hereinafter.
- FIG. 4 is a schematic configuration diagram of a hybrid vehicle 1 in which the integrated cycle 30 is mounted.
- the integrated cycle 30 indicates the entire system including a circuit (passages) for cooling water and exhaust air in addition to a circuit (passages) in which the refrigerant of the Rankine cycle 31 and the refrigeration cycle 51 is circulated and constituent elements such as pumps, expanders and condensers provided at intermediate positions of the circuit.
- an engine 2 , a motor generator 81 and an automatic transmission 82 are coupled in series and an output of the automatic transmission 82 is transmitted to drive wheels 85 via a propeller shaft 83 and a differential gear 84 .
- a first drive shaft clutch 86 is provided between the engine 2 and the motor generator 81 .
- one of frictional engagement elements of the automatic transmission 82 is configured as a second drive shaft clutch 87 .
- the first and second drive shaft clutches 86 , 87 are connected to an engine controller 71 , and connection and disconnection (connected state) thereof are controlled according to a driving condition of the hybrid vehicle 1 .
- connection and disconnection connected state
- the engine 2 includes an exhaust passage 3 , which is composed of an exhaust manifold 4 and an exhaust pipe 5 connected to a collection part of the exhaust manifold 4 .
- the exhaust pipe 5 is branched off into a bypass exhaust pipe 6 at an intermediate position and an exhaust heat recovery device 22 for heat exchange between exhaust air and cooling water is provided in a section of the exhaust pipe 5 bypassed by the bypass exhaust pipe 6 .
- the exhaust heat recovery device 22 and the bypass exhaust pipe 6 are united into an exhaust heat recovery unit 23 and arranged between an underfloor catalyst 88 and a sub-muffler 89 downstream of the underfloor catalyst 88 as shown in FIG. 6 .
- the engine 2 is mounted on the vehicle body by being fixed to a frame member forming a vehicle body skeleton of the hybrid vehicle 1 via an unillustrated engine mount.
- the engine mount functions to reduce (damp) vibration transmitted between the engine 2 and the vehicle body and makes it difficult to transmit the vibration of the engine 2 to the vehicle body and the vibration of the vehicle body to the engine 2 .
- the engine 2 and the vehicle body produce different types of vibration, wherefore an engine 2 side component fixed to the engine 2 and a vehicle body side component fixed to the vehicle body also produce different types of vibration.
- Even components generally connected by a connecting component having high rigidity need to be connected by a connecting component having high flexibility (excellent in flexibility) to absorb relative displacements caused by vibration when they are separately mounted on the engine 2 and the vehicle body.
- Cooling water of about 80 to 90° C. coming out from the engine 2 separately flows in a cooling water passage 13 passing through a radiator 11 and a bypass cooling water passage 14 bypassing the radiator 11 . Thereafter, two flows join again in a thermostat valve 15 for determining an allocation of cooling water flow rates in the both passages 13 , 14 and are further returned to the engine 2 by way of a cooling water pump 16 .
- the cooling water pump 16 is driven by the engine 2 and a rotation speed thereof is synchronized with an engine rotation speed.
- the thermostat valve 15 relatively increases an amount of the cooling water passing through the radiator 11 by increasing a valve opening on the side of the cooling water passage 13 when a cooling water temperature is high, and relatively decreases the amount of the cooling water passing through the radiator 11 by reducing the valve opening on the side of the cooling water passage 13 when the cooling water temperature is low.
- the cooling water temperature is particularly low such as before the warm-up of the engine 2
- a total amount of the cooling water flows in the bypass cooling water passage 14 while completely bypassing the radiator 11 .
- the bypass cooling water passage 14 bypassing the radiator 11 is composed of a first bypass cooling water passage 24 branched off from the cooling water passage 13 and directly connected to a heat exchanger 36 to be described later and a second bypass cooling water passage 25 branched off from the cooling water passage 13 and connected to the heat exchanger 36 by way of the exhaust heat recovery device 22 .
- the heat exchanger 36 for performing heat exchange with the refrigerant of the Rankine cycle 31 is provided in the bypass cooling water passage 14 .
- This heat exchanger 36 is formed by integrating an evaporator and a superheater.
- two cooling water passages 36 a, 36 b are arranged substantially in a row and a refrigerant passage 36 c in which the refrigerant of the Rankine cycle 31 flows is provided adjacent to the cooling water passages 36 a, 36 b so as to enable heat exchange between the refrigerant and the cooling water.
- each passage 36 a, 36 b, 36 c is so configured that the refrigerant of the Rankine cycle 31 and the cooling water flow in opposite directions when the entire heat exchanger 36 is viewed from above.
- one cooling water passage 36 a located on an upstream side (left side of FIG. 1 ) for the refrigerant of the Rankine cycle 31 is inserted in the first bypass cooling water passage 24 .
- This cooling water passage 36 a and a left part of the heat exchanger formed by a refrigerant passage part adjacent to this cooling water passage 36 a constitute the evaporator for heating the refrigerant of the Rankine cycle 31 flowing in the refrigerant passage 36 c by directly introducing the cooling water coming out from the engine 2 to the cooling water passage 36 a.
- the cooling water having passed through the exhaust heat recovery device 22 via the second bypass cooling water passage 25 is introduced to the other cooling water passage 36 b on a downstream side (right side of FIG. 1 ) for the refrigerant of the Rankine cycle 31 .
- This cooling water passage 36 b and a right part (downstream side for the refrigerant of the Rankine cycle 31 ) of the heat exchanger formed by a refrigerant passage part adjacent to this cooling water 36 b constitute the superheater for overheating the refrigerant flowing in the refrigerant passage 36 c by introducing the cooling water obtained by further heating the cooling water at the exit of the engine 2 by the exhaust air to the cooling water passage 36 b.
- a cooling water passage 22 a of the exhaust heat recovery device 22 is provided adjacent to the exhaust pipe 5 .
- the cooling water can be heated, for example, up to 110 to 115° C. by the high-temperature exhaust air.
- the cooling water passage 22 a is so configured that the exhaust air and the cooling water flow in opposite directions when the entire exhaust heat recovery device 22 is viewed from above.
- a control valve 26 is disposed in the second bypass cooling water passage 25 including the exhaust heat recovery device 22 .
- An opening of this control valve 26 is reduced when a temperature detected by a cooling water temperature sensor 74 at the exit of the engine 2 reaches a predetermined value or higher so that an engine water temperature indicating the temperature of the cooling water in the engine 2 does not exceed a permissible temperature (e.g. 100° C.) for preventing, for example, efficiency deterioration of the engine 2 and the occurrence of knocking.
- a permissible temperature e.g. 100° C.
- the bypass exhaust pipe 6 bypassing the exhaust heat recovery device 22 is provided and a thermostat valve 7 for controlling an amount of the exhaust air passing through the exhaust heat recovery device 22 and an amount of the exhaust air passing through the bypass exhaust pipe 6 is provided in a branched part of the bypass exhaust pipe 6 .
- a valve opening of the thermostat valve 7 is adjusted based on the temperature of the cooling water coming out from the exhaust heat recovery device 22 so that the temperature of the cooling water coming out from the exhaust heat recovery device 22 does not exceed a predetermined temperature (e.g. boiling temperature of 120°).
- the heat exchanger 36 , the thermostat valve 7 and the exhaust heat recovery device 22 are united into the exhaust heat recovery unit 23 and arranged at intermediate positions of the exhaust pipe under a substantially central part of a floor in a vehicle width direction.
- the thermostat valve 7 may be a relatively simple temperature sensitive valve using a bimetal or the like or may be a control valve controlled by a controller to which a temperature sensor output is input. Since an adjustment of a heat exchange amount from the exhaust air into the cooling water by the thermostat valve 7 causes a relatively long delay, it is difficult to prevent the engine water temperature from exceeding the permissible temperature if the thermostat valve 7 is singly adjusted.
- control valve 26 in the second bypass cooling water passage 25 is controlled based on the engine water temperature (exit temperature)
- a heat recovery amount can be quickly reduced to reliably prevent the engine water temperature from exceeding the permissible temperature.
- an exhaust heat recovery amount can be increased by performing heat exchange until the temperature of the cooling water coming out from the exhaust heat recovery device 22 reaches a high temperature (e.g. 110 to 115° C.) exceeding the permissible temperature of the engine water temperature.
- the cooling water coming out from the cooling water passage 36 b joins the first bypass cooling water passage 24 via the second bypass cooling water passage 25 .
- the valve opening of the thermostat valve 15 on the side of the cooling water passage 13 is reduced and the amount of the cooling water passing through the radiator 11 is relatively reduced.
- the valve opening of the thermostat valve 15 on the side of the cooling water passage 13 is increased and the amount of the cooling water passing through the radiator 11 is relatively increased. Based on such an operation of the thermostat valve 15 , the cooling water temperature of the engine 2 is appropriately maintained and heat is appropriately supplied (recovered) to the Rankine cycle 31 .
- the Rankine cycle 31 is described.
- the Rankine cycle 31 is configured not as a simple Rankine cycle, but as a part of the integrated cycle 30 integrated with the refrigeration cycle 51 .
- the Rankine cycle 31 as a basis is described first and the refrigeration cycle 51 is then mentioned.
- the Rankine cycle 31 is a system for recovering the exhaust heat of the engine 2 by the refrigerant using the cooling water of the engine 2 and regenerating the recovered exhaust heat as power.
- the Rankine cycle 31 includes a refrigerant pump 32 , the heat exchanger 36 as a superheater, an expander 37 and the condenser 38 and each constituent element is connected by refrigerant passages 41 to 44 in which the refrigerant (R134a, etc.) is circulated.
- the refrigerant passages 41 to 44 are generally formed by ordinary metal pipes (steel pipes) which easily ensure refrigerant sealability and have relatively high rigidity, but flexible pipes having high flexibility are used as some of them in the present embodiment. This is described in detail later.
- a shaft of the refrigerant pump 32 is arranged to be coupled to an output shaft of the expander 37 on the same axis, the refrigerant pump 32 is driven by an output (power) generated by the expander 37 and the generated power is supplied to an output shaft (crankshaft) of the engine 2 (see 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 mounted between a pump pulley 33 provided on the tip of the shaft of the refrigerant pump 32 and a crank pulley 2 a (see FIG. 1 ).
- the output shaft of the expander 37 and that of the engine 2 are configured to be able to transmit power.
- a gear-type pump is used as the refrigerant pump 32 and a scroll type expander is used as the expander 37 (see FIGS. 2B , 2 C).
- the refrigerant pump 32 and the expander 37 are mounted on the engine 2 as shown in FIG. 5 .
- An electromagnetic clutch (hereinafter, this clutch is referred to as an “expander clutch”) 35 (first clutch) is provided between the pump pulley 33 and the refrigerant pump 32 to make the refrigerant pump 32 and the expander 37 connectable to and disconnectable from the engine 2 (see FIG. 2A ).
- the expander clutch 35 when the output generated by the expander 37 exceeds a drive force of the refrigerant pump 32 and the friction of a rotating body (predicted expander torque is positive), the rotation of the engine output shaft can be assisted by the output generated by the expander 37 .
- the expander clutch 35 may be provided at any intermediate position of a 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 via the refrigerant passage 41 .
- the heat exchanger 36 is a heat exchanger for performing heat exchange between the cooling water of the engine 2 and the refrigerant and evaporating and overheating the refrigerant.
- the refrigerant from the heat exchanger 36 is supplied to the expander 37 via the refrigerant passage 42 .
- the expander 37 is a steam turbine for converging heat into rotational energy by expanding the evaporated and overheated refrigerant.
- the power recovered by the expander 37 drives the refrigerant pump 32 and is transmitted to the engine 2 via a belt transmission mechanism to assist the rotation of the engine 2 .
- the refrigerant from the expander 37 is supplied to the condenser 38 via refrigerant passages 43 a, 43 b.
- the condenser 38 is a heat exchanger for performing heat exchange between outside air and the refrigerant and cooling and liquefying the refrigerant.
- the condenser 38 is arranged in parallel with the radiator 11 and cooled by a radiator fan 12 .
- the condenser 38 is mounted on the vehicle body.
- the refrigerant passage 43 a is connected to the expander 37 .
- the refrigerant passage 43 b connects the refrigerant passage 43 a and the condenser 38 .
- the refrigerant passages 43 a, 43 b are connected at a refrigeration cycle junction 46 to be described later.
- the refrigerant passage 43 a connecting the engine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 43 b to absorb a relative displacement caused by vibration.
- High flexibility means low rigidity and being freely deformable.
- the flexible pipe has a bellows-like shape or is made of a material which is soft and excellent in flexibility.
- the refrigerant passage 43 a can be freely bent at any intermediate position and can absorb vibration if the vibration is transmitted.
- a part of the refrigerant passage 43 a on the side of the expander 37 mounted on the engine 2 vibrates together with the engine 2 and the expander 37 .
- the refrigerant passage 43 b is a pipe connected to the condenser 38 and having lower flexibility, i.e. higher rigidity than the refrigerant passage 43 a such as a stainless steel pipe or an aluminum pipe.
- the refrigerant passage 43 b vibrates together with the condenser 38 mounted on the vehicle body.
- the refrigerant passage 43 a is connected to the expander 37 mounted on the engine 2 . Further, the refrigerant passage 43 b is connected to the condenser 38 mounted on the vehicle body. Thus, when the vehicle is driven, a vibration frequency of the refrigerant passage 43 a and that of the refrigerant passage 43 b differ.
- the refrigerant passage 43 a is formed by a flexible pipe for refrigerant, whereby a vibrational difference between the part of the refrigerant passage 43 a on the side of the engine 2 and the refrigerant passage 43 b is absorbed by the refrigerant passage 43 a.
- the refrigerant liquefied by the condenser 38 is returned to the refrigerant pump 32 via refrigerant passages 44 a, 44 b.
- the refrigerant returned to the refrigerant pump 32 is fed to the heat exchanger 36 again by the refrigerant pump 32 and circulates through each constituent element of the Rankine cycle 31 .
- the refrigerant passage 44 a is connected to the condenser 38 .
- the refrigerant passage 44 b connects the refrigerant passage 43 a and the refrigerant pump 32 .
- the refrigerant passages 44 a, 44 b are connected at a refrigeration cycle junction 45 to be described later.
- the refrigerant passage 44 a is, for example, a stainless steel pipe or an aluminum pipe having lower flexibility than the refrigerant passage 44 b.
- the refrigerant passage 44 a vibrates together with the condenser 38 .
- the refrigerant passage 44 b connecting the engine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 44 a to absorb a relative displacement caused by vibration.
- a part of the refrigerant passage 44 b on the side of the engine 2 vibrates together with the engine 2 by having the vibration of the engine 2 transmitted thereto.
- the refrigeration cycle 51 is described. Since the refrigeration cycle 51 shares the refrigerant circulating in the Rankine cycle 31 , the refrigeration cycle 51 is integrated with the Rankine cycle 31 and the configuration thereof is simple. Specifically, the refrigeration cycle 51 includes a compressor 52 , the condenser 38 and an evaporator 55 .
- the compressor 52 is a fluid machine for compressing the refrigerant of the refrigeration cycle 51 at high temperature and high pressure.
- the compressor 52 is mounted on the vehicle body.
- the compressor 52 is an electric compressor and power is supplied thereto from an unillustrated battery or the like.
- the refrigerant from the compressor 52 is supplied to the condenser 38 via the refrigerant passage 43 b after joining the refrigerant passage 43 a at the refrigeration cycle junction 46 via a refrigerant passage 56 .
- the refrigerant passage 56 is formed by a general metal pipe (steel pipe) having relatively high rigidity.
- the condenser 38 is a heat exchanger for condensing and liquefying the refrigerant by heat exchange with outside air.
- the liquid refrigerant from the condenser 38 is supplied to the evaporator 55 via a refrigerant passage 57 branched off from the refrigerant passage 44 a at the refrigeration cycle junction 45 .
- the refrigerant passage 57 is also formed by a general metal pipe (steel pipe) having relatively high rigidity.
- the evaporator 55 is arranged in a case of an air conditioning unit in the same manner as an unillustrated heater core.
- the evaporator 55 is a heat exchanger for evaporating the liquid refrigerant from the condenser 38 and cooling air conditioning air from a blower fan by latent heat of evaporation.
- the refrigerant evaporated by the evaporator 55 is returned to the compressor 52 via a refrigerant passage 58 . It should be noted that a mixing ratio of the air conditioning air cooled by the evaporator 55 and that heated by the heater core is changed according to an opening of an air mix door to adjust the temperature to a temperature set by a passenger.
- the integrated cycle 30 composed of the Rankine cycle 31 and the refrigeration cycle 51 appropriately includes various valves at intermediate positions of the circuit to control the refrigerant flowing in the cycle.
- a pump upstream valve 61 is provided in the refrigerant passage 44 b allowing communication between the refrigeration cycle junction 45 and the refrigerant pump 32 and an expander upstream valve 62 is provided in the refrigerant passage 42 allowing communication between the heat exchanger 36 and the expander 37 .
- a check valve 63 for preventing a reverse flow of the refrigerant from the heat exchanger 36 to the refrigerant pump 32 is provided in the refrigerant passage 41 allowing communication between the refrigerant pump 32 and the heat exchanger 36 .
- a check valve 64 for preventing a reverse flow of the refrigerant from the refrigeration cycle junction 46 to the expander 37 is also provided in the refrigerant passage 43 a allowing communication between the expander 37 and the refrigeration cycle junction 46 .
- an expander bypass passage 65 is provided which bypasses the expander 37 from a side upstream of the expander upstream valve 62 and joins at a side upstream of the check valve 64 , and a bypass valve 66 is provided in this expander bypass passage 65 .
- a pressure regulating valve 68 is provided in a passage 67 bypassing the bypass valve 66 .
- an air conditioning circuit valve 69 is provided in the refrigerant passage 57 connecting the refrigeration cycle junction 45 and the evaporator 55 .
- any of the above four valves 61 , 62 , 66 and 69 is an electromagnetic on-off valve.
- To the engine controller 71 are input a signal indicating a pressure upstream of the expander detected by a pressure sensor 72 , a signal indicating a refrigerant pressure Pd at the exit of the condenser 38 detected by a pressure sensor 73 , a rotation speed signal of the expander 37 , etc.
- the compressor 52 of the refrigeration cycle 51 and the radiator fan 12 are controlled and the opening and closing of the above four electromagnetic on-off valves 61 , 62 , 66 and 69 are controlled based on each of these input signals according to a predetermined driving condition.
- an expander torque (regenerative power) is predicted based on the pressure upstream of the expander detected by the pressure sensor 72 and the expander rotation speed, and the expander clutch 35 is engaged when this predicted expander torque is positive (the rotation of the engine output shaft can be assisted) and released when the predicted expander torque is zero or negative.
- the expander torque can be predicted with high accuracy based on the sensor detected pressure and the expander rotation speed as compared with the case where the expander torque (regenerative power) is predicted from the exhaust temperature, and the expander clutch 35 can be properly engaged/released according to a generation state of the expander torque (for further details, see JP2010-190185A).
- the above four on-off valves 61 , 62 , 66 and 69 and two check valves 63 , 64 are refrigeration system valves. Functions of these refrigeration system valves are shown anew in FIG. 3 .
- the pump upstream valve 61 is for preventing an uneven distribution of the refrigerant (containing a lubricant component) to the Rankine cycle 31 by being closed under a predetermined condition that makes the refrigerant easily unevenly distributed to the circuit of the Rankine cycle 31 as compared with the circuit of the refrigeration cycle 51 such as during the stop of the Rankine cycle 31 , and closes the circuit of the Rankine cycle 31 in cooperation with the check valve 64 downstream of the expander 37 as described later.
- the expander upstream valve 62 cuts off the refrigerant passage 42 when a refrigerant pressure from the heat exchanger 36 is relatively low, so that the refrigerant from the heat exchanger 36 can be maintained until a high pressure is reached.
- the bypass valve 66 is for shortening a start-up time of the Rankine cycle 31 by being opened to actuate the refrigerant pump 32 after the expander 37 is bypassed such as when an amount of the refrigerant present on the side of the Rankine cycle 31 is insufficient such as at the start-up of the Rankine cycle 31 .
- the check valve 63 upstream of the heat exchanger 36 is for maintaining the refrigerant supplied to the expander 37 at a high pressure in cooperation with the bypass valve 66 , the pressure regulating valve 68 and the expander upstream valve 62 .
- the operation of the Rankine cycle is stopped and the circuit is closed in a section before and after the heat exchanger, whereby the refrigerant pressure during the stop is increased so that the Rankine cycle can be quickly restarted utilizing the high-pressure refrigerant.
- the pressure regulating valve 68 functions as a relief valve for allowing the refrigerant having reached an excessively high pressure to escape by being opened when the pressure of the refrigerant supplied to the expander 37 becomes excessively high.
- the check valve 64 downstream of the expander 37 is for preventing an uneven distribution of the refrigerant to the Rankine cycle 31 in cooperation with the aforementioned pump upstream valve 61 . If the engine 2 is not warm yet immediately after the operation of the hybrid vehicle 1 is started, the temperature of the Rankine cycle 31 is lower than that of the refrigeration cycle 51 and the refrigerant may be unevenly distributed toward the Rankine cycle 31 . Although a probability of uneven distribution toward the Rankine cycle 31 is not very high, there is a request to resolve even a slightly uneven distribution of the refrigerant to secure the refrigerant of the refrigeration cycle 51 , for example, immediately after the start of the vehicle operation in summer since it is wished to quickly cool vehicle interior and cooling capacity is required most. Accordingly, the check valve 64 is provided to prevent the uneven distribution of the refrigerant toward the Rankine cycle 31 .
- the compressor 52 is not so structured that the refrigerant can freely pass when the drive is stopped, and can prevent an uneven distribution of the refrigerant to the refrigeration cycle 51 in cooperation with the air conditioning circuit valve 69 . This is described.
- the refrigerant moves from the Rankine cycle 31 that is in steady operation and has a relatively high temperature to the refrigeration cycle 51 , whereby the refrigerant circulating in the Rankine cycle 31 may become insufficient.
- the temperature of the evaporator 55 is low immediately after the cooling is stopped and the refrigerant tends to stay in the evaporator 55 that has a relatively large volume and a low temperature.
- the uneven distribution of the refrigerant to the refrigeration cycle 51 is prevented by stopping the drive of the compressor 52 to block a movement of the refrigerant from the condenser 38 to the evaporator 55 and closing the air conditioning circuit valve 69 .
- FIG. 5 is a schematic perspective view of the engine 2 showing an entire package of the engine 2 .
- the heat exchanger 36 is arranged vertically above the exhaust manifold 4 . That is, the heat exchanger 36 is mounted on the engine 2 .
- the mountability of the Rankine cycle 31 on the engine 2 is improved.
- a tension pulley 8 is provided on the engine 2 .
- FIGS. 7A and 7B are graphs showing operating regions of the Rankine cycle 31 .
- FIG. 7A shows the operating region of the Rankine cycle 31 when a horizontal axis represents outside air temperature and a vertical axis represents engine water temperature (cooling water temperature)
- FIG. 7B shows the operating region of the Rankine cycle 31 when a horizontal axis represents engine rotation speed and a vertical axis represents engine torque (engine load).
- the Rankine cycle 31 is operated when a predetermined condition is satisfied.
- the Rankine cycle 31 is operated when both of these conditions are satisfied.
- FIG. 7A the operation of the Rankine cycle 31 is stopped in a region on a low water temperature side where the warm-up of the engine 2 is prioritized and a region on a high outside temperature side where a load of the compressor 52 increases. During the warm-up in which exhaust temperature is low and recovery efficiency is poor, the cooling water temperature is quickly increased rather by not operating the Rankine cycle 31 .
- the Rankine cycle 31 is stopped to provide the refrigeration cycle 51 with sufficient refrigerant and the cooling capacity of the condenser 38 .
- FIG. 7B the operation of the Rankine cycle 31 is stopped in the EV running region and a region on a high rotation speed side where the friction of the expander 37 increases since the vehicle is the hybrid vehicle 1 . Since it is difficult to provide the expander 37 with a highly efficient structure having little friction at all the rotation speeds, the expander 37 is so configured (dimensions and the like of each part of the expander 37 are set) in the case of FIG. 7B as to realize small friction and high efficiency in an engine rotation speed region where an operation frequency is high.
- FIG. 8 diagrammatically shows a state of pipes of the integrated cycle 30 of the first embodiment.
- each of the refrigerant pump 32 , the heat exchanger 36 and the expander 37 of the Rankine cycle 31 is mounted on the engine 2 and the condenser 38 is mounted on the vehicle body.
- the refrigerant pump 32 and the heat exchanger 36 , and the heat exchanger 36 and the expander 37 are connected by general metal pipes (steel pipes) 101 having relatively high rigidity.
- the expander 37 and the condenser 38 , and the condenser 38 and the refrigerant pump 32 are connected by passages (conduits) having high flexibility and including a flexible pipe 100 at least in an intermediate part.
- the present embodiment is not only configured to be able to drive the refrigerant pump 32 by the engine 2 by mounting the refrigerant pump 32 on the engine 2 , but also configured to be able to drive the refrigerant pump 32 by a regenerative output of the expander 37 by mounting the expander 37 on the engine 2 , and energy efficiency can be improved by enabling the refrigerant pump 32 to be driven also utilizing the regenerative output of the expander 37 while increasing a degree of freedom in the operation of the Rankine cycle 31 by enabling the refrigerant pump 32 to be driven by the power of the engine 2 .
- the refrigerant pump 32 and the heat exchanger 36 , and the heat exchanger 36 and the expander 37 can be connected by the passages (conduits) 101 having relatively high rigidity, and only the expander 37 and the condenser 38 , and the condenser 38 and the refrigerant pump 32 are connected by the flexible pipes 100 having high flexibility. This can suppress cost by reducing the number of the relatively expensive flexible pipes 100 . Specifically, only two flexible pipes 100 are provided at intermediate positions of the circuit of the Rankine cycle 31 .
- the refrigerant passage 43 a connected to the expander 37 mounted on the engine 2 is formed by a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 43 b connected to the condenser 38 mounted on the vehicle body.
- the refrigerant passage 43 a can be formed by a metal pipe less expensive than the flexible pipe for refrigerant such as a copper pipe, a stainless steel pipe or an aluminum pipe, and the number of the expensive flexible pipes for refrigerant can be reduced.
- the cost of the integrated cycle 30 can be reduced.
- the length of the pipe connecting the expander 37 and the condenser 38 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of the integrated cycle 30 can be improved.
- At least a part of the refrigerant passage 44 b connected to the refrigerant pump 32 mounted on the engine 2 is formed by a flexible pipe for refrigerant having higher flexibility than the refrigerant passage 44 a connected to the condenser 38 .
- This enables the refrigerant passage 44 b to absorb a vibrational difference between the refrigerant passage 44 a and the part of the refrigerant passage 44 b on the side of the engine 2 .
- the refrigerant passage 44 a can be formed by a metal pipe less expensive than the flexible pipe for refrigerant, and the number of the expensive flexible pipes for refrigerant can be reduced. Thus, the cost of the integrated cycle 30 can be reduced.
- the length of the pipe connecting the condenser 38 and the refrigerant pump 32 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of the integrated cycle 30 can be improved.
- the refrigerant passage 43 a By forming the refrigerant passage 43 a by a flexible pipe for refrigerant and forming the refrigerant passage 43 b, for example, by a metal pipe in the integrated cycle 30 in which the output shaft of the expander 37 and that of the engine 2 are configured to be able to transmit power, the above effects can be obtained more.
- FIGS. 9 and 10 Next, a second embodiment of the present invention is described using FIGS. 9 and 10 .
- FIG. 9 is a schematic configuration diagram of a hybrid vehicle in the present embodiment.
- FIG. 10 is a schematic configuration diagram of an integrated cycle in the present embodiment. The second embodiment is described, centering on parts different from the first embodiment. The same configuration as the first embodiment is denoted by the same reference signs as in the first embodiment and not described here.
- a compressor 59 is mounted on an engine 2 and driven by the engine 2 .
- a compressor pulley 53 is fixed to a drive shaft of the compressor 59 and a belt 34 is mounted on this compressor pulley 53 and a crank pulley 2 a.
- a drive force of the engine 2 is transmitted to the compressor pulley 53 via this belt 34 to drive the compressor 59 .
- an electromagnetic clutch 54 is provided between the compressor pulley 53 and the compressor 59 to make the compressor 59 and the compressor pulley 53 connectable to and disconnectable from each other.
- a refrigerant passage 56 connected to the compressor 59 is a flexible pipe for refrigerant having higher flexibility than a refrigerant passage 43 b.
- a refrigerant passage 58 provided between the compressor 59 and an evaporator 55 and connected to the compressor 59 is a flexible pipe for refrigerant similarly to the refrigerant passage 56 .
- a vibration frequency of the refrigerant passage 56 connected to the compressor 59 and that of the refrigerant passage 43 b connected to a condenser 38 differ when the vehicle is driven.
- a vibrational difference between the refrigerant passages 56 and 43 b is absorbed by forming the refrigerant passage 56 by the flexible pipe for refrigerant.
- FIG. 11 diagrammatically shows a state of pipes of the integrated cycle 30 of the second embodiment.
- a difference from the first embodiment is that the refrigerant passages before and after the compressor 59 are formed by flexible pipes 100 since the compressor 59 is mounted on the engine 2 .
- cost can be suppressed by reducing the number of relatively expensive flexible pipes 100 .
- only two flexible pipes 100 are provided at intermediate positions of a circuit of a Rankine cycle 31 and the number of the flexible pipes 100 is suppressed to four in the entire integrated cycle 30 .
- the refrigerant passage 56 is formed by the flexible pipe for refrigerant and the refrigerant passage 56 is connected to the refrigerant passage 43 b at a refrigeration cycle junction 46 . This enables the refrigerant passage 43 b to absorb a vibrational difference between the refrigerant passages 43 b and 56 .
- the third embodiment is described, centering on parts different from the second embodiment.
- a refrigerant passage 43 b is formed by a flexible pipe having higher flexibility than refrigerant passages 43 a and 56 . Further, the refrigerant passages 43 a and 56 are formed, for example, by stainless steel pipes or aluminum pipes having low flexibility.
- FIG. 12 diagrammatically shows a state of pipes of an integrated cycle 30 of the third embodiment.
- a difference from the second embodiment is that a pipe connecting an expander 37 and a condenser 38 and a pipe connecting a compressor 59 and the condenser 38 join each other at an intermediate position and a part after the junction is formed by a flexible pipe 100 .
- cost can be suppressed by reducing the number of relatively expensive flexible pipes 100 .
- only two flexible pipes 100 are provided at intermediate positions of a circuit of a Rankine cycle 31 and the number of the flexible pipes 100 is suppressed to three in the entire integrated cycle 30 .
- a refrigerant passage 43 b connected to the condenser 38 is formed by a flexible pipe for refrigerant
- a refrigerant passage 43 a connected to the expander 37 and a refrigerant passage 56 connected to the compressor 59 are formed, for example, by stainless pipes or aluminum pipes less expensive than flexible pipes for refrigerant. This enables the absorption of a vibrational difference between the refrigerant passage 43 b and the refrigerant passages 43 a, 56 .
- the refrigerant passages 43 a, 56 can be formed by inexpensive pipes and the cost of the integrated cycle 30 can be reduced.
- a refrigerant passage 44 a may be formed by a flexible pipe for refrigerant and a refrigerant passage 44 b may be formed by a stainless steel pipe or an aluminum pipe.
- the length of the pipes connecting the expander 37 or the compressor 59 and the condenser 38 and the pipe connecting the condenser 38 and a refrigerant pump 32 can be shortened, a pressure loss in the pipes can be reduced and the efficiency of the integrated cycle 30 can be improved.
- a pipe configured to include a flexible pipe for refrigerant having high flexibility in a part (at an intermediate position) of a general metal pipe may be used as a passage pipe having high flexibility to absorb a relative displacement caused by vibration.
Abstract
A Rankine cycle system includes a refrigerant pump which is mounted on an engine and is configured to feed refrigerant, a heat exchanger which is mounted on the engine and is configured to recover exhaust heat of the engine to the refrigerant, an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger, and a condenser which is mounted on a vehicle body and is configured to condense the refrigerant expanded by the expander. The expander and the condenser, and the condenser and the refrigerant pump are connected by flexible pipes having higher flexibility than other pipes.
Description
- The present invention relates to a Rankine cycle system.
- Conventionally, it is disclosed in JP2001-182504A to mount an evaporator and an expander on an engine in an on-vehicle Rankine cycle system.
- The evaporator and the expander are connected to another member, e.g. a condenser mounted on a vehicle body via pipes. Since a member mounted on an engine and a member mounted on the vehicle body differ in vibration frequency, the member mounted on the engine and that mounted on the vehicle body are connected by a flexible pipe. Since flexible pipes are more expensive than pipes having high rigidity such as stainless steel pipes and aluminum pipes, the usage thereof is preferably reduced.
- However, in the above invention, no consideration is made on such a point and there is a problem of increasing the cost of the Rankine cycle system.
- The present invention was developed to solve the above problem and aims to reduce the cost of a Rankine cycle system by reducing the usage of flexible pipes.
- A Rankine cycle system according to one aspect of the present invention includes a refrigerant pump which is mounted on an engine and is configured to feed refrigerant, a heat exchanger which is mounted on the engine and is configured to recover exhaust heat of the engine to the refrigerant, an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger, and a condenser which is mounted on a vehicle body and is configured to condense the refrigerant expanded by the expander. In the Rankine cycle system, the expander and the condenser, and the condenser and the refrigerant pump are connected by flexible pipes having higher flexibility than other pipes.
- Embodiments of the present invention and advantages thereof are described in detail below with reference to the accompanying drawings.
-
FIG. 1 is a schematic configuration diagram of an integrated cycle of a first embodiment of the present invention, -
FIG. 2A is a schematic sectional view of an expander pump formed by integrating a pump and an expander, -
FIG. 2B is a schematic sectional view of a refrigerant pump, -
FIG. 2C is a schematic sectional view of an expander, -
FIG. 3 is a schematic diagram showing functions of refrigeration system valves, -
FIG. 4 is a schematic configuration diagram of a hybrid vehicle, -
FIG. 5 is a schematic perspective view of an engine, -
FIG. 6 is a schematic diagram showing an arrangement of an exhaust pipe when the vehicle is viewed from below, -
FIG. 7A is a characteristic graph of a Rankine cycle operating region, -
FIG. 7B is a characteristic graph of a Rankine cycle operating region, -
FIG. 8 is a view diagrammatically showing a state of pipes of the integrated cycle of the first embodiment, -
FIG. 9 is a schematic configuration diagram of a hybrid vehicle of a second embodiment of the present invention, -
FIG. 10 is a schematic configuration diagram of an integrated cycle of the second embodiment of the present invention, -
FIG. 11 is a view diagrammatically showing a state of pipes of the integrated cycle of the second embodiment, and -
FIG. 12 is a view diagrammatically showing a state of pipes of an integrated cycle of a third embodiment. -
FIG. 1 is a schematic configuration diagram showing an entire system of a Rankinecycle 31 which is a premise of the present invention. The Rankinecycle 31 ofFIG. 1 is configured to share refrigerant and acondenser 38 with arefrigeration cycle 51 and a Rankine cycle system obtained by integrating the Rankinecycle 31 and therefrigeration cycle 51 is referred to as an integratedcycle 30 hereinafter.FIG. 4 is a schematic configuration diagram of ahybrid vehicle 1 in which the integratedcycle 30 is mounted. It should be noted that the integratedcycle 30 indicates the entire system including a circuit (passages) for cooling water and exhaust air in addition to a circuit (passages) in which the refrigerant of the Rankinecycle 31 and therefrigeration cycle 51 is circulated and constituent elements such as pumps, expanders and condensers provided at intermediate positions of the circuit. - In the
hybrid vehicle 1, anengine 2, amotor generator 81 and anautomatic transmission 82 are coupled in series and an output of theautomatic transmission 82 is transmitted to drivewheels 85 via apropeller shaft 83 and adifferential gear 84. A firstdrive shaft clutch 86 is provided between theengine 2 and themotor generator 81. Further, one of frictional engagement elements of theautomatic transmission 82 is configured as a seconddrive shaft clutch 87. The first and seconddrive shaft clutches engine controller 71, and connection and disconnection (connected state) thereof are controlled according to a driving condition of thehybrid vehicle 1. In thehybrid vehicle 1, as shown inFIG. 7B , when a vehicle speed is in an EV running region where the efficiency of theengine 2 is poor, theengine 2 is stopped, the firstdrive shaft clutch 86 is disengaged and the seconddrive shaft clutch 87 is connected, whereby thehybrid vehicle 1 is caused to run only by a drive force by themotor generator 81. On the other hand, when the vehicle speed deviates from the EV running region and transitions to a Rankine cycle operating region, the Rankine cycle 31 (to be described later) is operated by driving theengine 2. Theengine 2 includes an exhaust passage 3, which is composed of anexhaust manifold 4 and anexhaust pipe 5 connected to a collection part of theexhaust manifold 4. Theexhaust pipe 5 is branched off into abypass exhaust pipe 6 at an intermediate position and an exhaustheat recovery device 22 for heat exchange between exhaust air and cooling water is provided in a section of theexhaust pipe 5 bypassed by thebypass exhaust pipe 6. The exhaustheat recovery device 22 and thebypass exhaust pipe 6 are united into an exhaustheat recovery unit 23 and arranged between anunderfloor catalyst 88 and asub-muffler 89 downstream of theunderfloor catalyst 88 as shown inFIG. 6 . - The
engine 2 is mounted on the vehicle body by being fixed to a frame member forming a vehicle body skeleton of thehybrid vehicle 1 via an unillustrated engine mount. The engine mount functions to reduce (damp) vibration transmitted between theengine 2 and the vehicle body and makes it difficult to transmit the vibration of theengine 2 to the vehicle body and the vibration of the vehicle body to theengine 2. As a result, theengine 2 and the vehicle body produce different types of vibration, wherefore anengine 2 side component fixed to theengine 2 and a vehicle body side component fixed to the vehicle body also produce different types of vibration. Even components generally connected by a connecting component having high rigidity need to be connected by a connecting component having high flexibility (excellent in flexibility) to absorb relative displacements caused by vibration when they are separately mounted on theengine 2 and the vehicle body. - First, an engine cooling water circuit is described based on
FIG. 1 . Cooling water of about 80 to 90° C. coming out from theengine 2 separately flows in acooling water passage 13 passing through aradiator 11 and a bypasscooling water passage 14 bypassing theradiator 11. Thereafter, two flows join again in athermostat valve 15 for determining an allocation of cooling water flow rates in the bothpassages engine 2 by way of acooling water pump 16. Thecooling water pump 16 is driven by theengine 2 and a rotation speed thereof is synchronized with an engine rotation speed. Thethermostat valve 15 relatively increases an amount of the cooling water passing through theradiator 11 by increasing a valve opening on the side of thecooling water passage 13 when a cooling water temperature is high, and relatively decreases the amount of the cooling water passing through theradiator 11 by reducing the valve opening on the side of thecooling water passage 13 when the cooling water temperature is low. When the cooling water temperature is particularly low such as before the warm-up of theengine 2, a total amount of the cooling water flows in the bypasscooling water passage 14 while completely bypassing theradiator 11. On the other hand, the valve opening on the side of the bypasscooling water passage 14 is not completely closed, and thethermostat valve 15 is configured not to completely stop the flow although a flow rate of the cooling water flowing in the bypasscooling water passage 14 decreases as compared with the case where the total amount of the cooling water flows in the bypasscooling water passage 14 when a flow rate of the cooling water flowing through theradiator 11 increases. The bypasscooling water passage 14 bypassing theradiator 11 is composed of a first bypasscooling water passage 24 branched off from thecooling water passage 13 and directly connected to aheat exchanger 36 to be described later and a second bypasscooling water passage 25 branched off from thecooling water passage 13 and connected to theheat exchanger 36 by way of the exhaustheat recovery device 22. - The
heat exchanger 36 for performing heat exchange with the refrigerant of the Rankinecycle 31 is provided in the bypasscooling water passage 14. Thisheat exchanger 36 is formed by integrating an evaporator and a superheater. Specifically, in theheat exchanger 36, twocooling water passages refrigerant passage 36 c in which the refrigerant of the Rankinecycle 31 flows is provided adjacent to thecooling water passages passage cycle 31 and the cooling water flow in opposite directions when theentire heat exchanger 36 is viewed from above. - In detail, one
cooling water passage 36 a located on an upstream side (left side ofFIG. 1 ) for the refrigerant of theRankine cycle 31 is inserted in the first bypass coolingwater passage 24. This coolingwater passage 36 a and a left part of the heat exchanger formed by a refrigerant passage part adjacent to thiscooling water passage 36 a constitute the evaporator for heating the refrigerant of theRankine cycle 31 flowing in therefrigerant passage 36 c by directly introducing the cooling water coming out from theengine 2 to the coolingwater passage 36 a. - The cooling water having passed through the exhaust
heat recovery device 22 via the second bypass coolingwater passage 25 is introduced to the othercooling water passage 36 b on a downstream side (right side ofFIG. 1 ) for the refrigerant of theRankine cycle 31. This coolingwater passage 36 b and a right part (downstream side for the refrigerant of the Rankine cycle 31) of the heat exchanger formed by a refrigerant passage part adjacent to this coolingwater 36 b constitute the superheater for overheating the refrigerant flowing in therefrigerant passage 36 c by introducing the cooling water obtained by further heating the cooling water at the exit of theengine 2 by the exhaust air to the coolingwater passage 36 b. - A cooling
water passage 22 a of the exhaustheat recovery device 22 is provided adjacent to theexhaust pipe 5. By introducing the cooling water at the exit of theengine 2 to the coolingwater passage 22 a of the exhaustheat recovery device 22, the cooling water can be heated, for example, up to 110 to 115° C. by the high-temperature exhaust air. The coolingwater passage 22 a is so configured that the exhaust air and the cooling water flow in opposite directions when the entire exhaustheat recovery device 22 is viewed from above. - A
control valve 26 is disposed in the second bypass coolingwater passage 25 including the exhaustheat recovery device 22. An opening of thiscontrol valve 26 is reduced when a temperature detected by a coolingwater temperature sensor 74 at the exit of theengine 2 reaches a predetermined value or higher so that an engine water temperature indicating the temperature of the cooling water in theengine 2 does not exceed a permissible temperature (e.g. 100° C.) for preventing, for example, efficiency deterioration of theengine 2 and the occurrence of knocking. When the engine water temperature approaches the permissible temperature, the amount of the cooling water passing through the exhaustheat recovery device 22 is reduced. This can reliably prevent the engine water temperature from exceeding the permissible temperature. - On the other hand, if the cooling water temperature increased by the exhaust
heat recovery device 22 becomes too high and the cooling water evaporates (boils) due to a reduction in the flow rate of the second bypass coolingwater passage 25, the flow of the cooling water in the cooling water passage may become poor and component temperatures may excessively increase. To avoid this, thebypass exhaust pipe 6 bypassing the exhaustheat recovery device 22 is provided and athermostat valve 7 for controlling an amount of the exhaust air passing through the exhaustheat recovery device 22 and an amount of the exhaust air passing through thebypass exhaust pipe 6 is provided in a branched part of thebypass exhaust pipe 6. Specifically, a valve opening of thethermostat valve 7 is adjusted based on the temperature of the cooling water coming out from the exhaustheat recovery device 22 so that the temperature of the cooling water coming out from the exhaustheat recovery device 22 does not exceed a predetermined temperature (e.g. boiling temperature of 120°). - The
heat exchanger 36, thethermostat valve 7 and the exhaustheat recovery device 22 are united into the exhaustheat recovery unit 23 and arranged at intermediate positions of the exhaust pipe under a substantially central part of a floor in a vehicle width direction. Thethermostat valve 7 may be a relatively simple temperature sensitive valve using a bimetal or the like or may be a control valve controlled by a controller to which a temperature sensor output is input. Since an adjustment of a heat exchange amount from the exhaust air into the cooling water by thethermostat valve 7 causes a relatively long delay, it is difficult to prevent the engine water temperature from exceeding the permissible temperature if thethermostat valve 7 is singly adjusted. However, since thecontrol valve 26 in the second bypass coolingwater passage 25 is controlled based on the engine water temperature (exit temperature), a heat recovery amount can be quickly reduced to reliably prevent the engine water temperature from exceeding the permissible temperature. Further, if there is a margin between the engine water temperature and the permissible temperature, an exhaust heat recovery amount can be increased by performing heat exchange until the temperature of the cooling water coming out from the exhaustheat recovery device 22 reaches a high temperature (e.g. 110 to 115° C.) exceeding the permissible temperature of the engine water temperature. The cooling water coming out from the coolingwater passage 36 b joins the first bypass coolingwater passage 24 via the second bypass coolingwater passage 25. - If the temperature of the cooling water flowing from the bypass cooling
water passage 14 toward thethermostat valve 15 is sufficiently reduced, for example, by heat exchange with the refrigerant of theRankine cycle 31 in theheat exchanger 36, the valve opening of thethermostat valve 15 on the side of the coolingwater passage 13 is reduced and the amount of the cooling water passing through theradiator 11 is relatively reduced. Conversely, if the temperature of the cooling water flowing from the bypass coolingwater passage 14 toward thethermostat valve 15 is increased such as because theRankine cycle 31 is not operated, the valve opening of thethermostat valve 15 on the side of the coolingwater passage 13 is increased and the amount of the cooling water passing through theradiator 11 is relatively increased. Based on such an operation of thethermostat valve 15, the cooling water temperature of theengine 2 is appropriately maintained and heat is appropriately supplied (recovered) to theRankine cycle 31. - Next, the
Rankine cycle 31 is described. Here, theRankine cycle 31 is configured not as a simple Rankine cycle, but as a part of theintegrated cycle 30 integrated with therefrigeration cycle 51. TheRankine cycle 31 as a basis is described first and therefrigeration cycle 51 is then mentioned. - The
Rankine cycle 31 is a system for recovering the exhaust heat of theengine 2 by the refrigerant using the cooling water of theengine 2 and regenerating the recovered exhaust heat as power. TheRankine cycle 31 includes arefrigerant pump 32, theheat exchanger 36 as a superheater, anexpander 37 and thecondenser 38 and each constituent element is connected byrefrigerant passages 41 to 44 in which the refrigerant (R134a, etc.) is circulated. Therefrigerant passages 41 to 44 are generally formed by ordinary metal pipes (steel pipes) which easily ensure refrigerant sealability and have relatively high rigidity, but flexible pipes having high flexibility are used as some of them in the present embodiment. This is described in detail later. - A shaft of the
refrigerant pump 32 is arranged to be coupled to an output shaft of theexpander 37 on the same axis, therefrigerant pump 32 is driven by an output (power) generated by theexpander 37 and the generated power is supplied to an output shaft (crankshaft) of the engine 2 (seeFIG. 2A ). The shaft of therefrigerant pump 32 and the output shaft of theexpander 37 are arranged in parallel with the output shaft of theengine 2, and abelt 34 is mounted between apump pulley 33 provided on the tip of the shaft of therefrigerant pump 32 and acrank pulley 2 a (seeFIG. 1 ). Specifically, the output shaft of theexpander 37 and that of theengine 2 are configured to be able to transmit power. It should be noted that, in the present embodiment, a gear-type pump is used as therefrigerant pump 32 and a scroll type expander is used as the expander 37 (seeFIGS. 2B , 2C). Therefrigerant pump 32 and theexpander 37 are mounted on theengine 2 as shown inFIG. 5 . - An electromagnetic clutch (hereinafter, this clutch is referred to as an “expander clutch”) 35 (first clutch) is provided between the
pump pulley 33 and therefrigerant pump 32 to make therefrigerant pump 32 and theexpander 37 connectable to and disconnectable from the engine 2 (seeFIG. 2A ). Thus, by connecting theexpander clutch 35 when the output generated by theexpander 37 exceeds a drive force of therefrigerant pump 32 and the friction of a rotating body (predicted expander torque is positive), the rotation of the engine output shaft can be assisted by the output generated by theexpander 37. By assisting the rotation of the engine output shaft using energy obtained by exhaust heat recovery in this way, fuel economy can be improved. Further, energy for driving therefrigerant pump 32 for circulating the refrigerant can also be generated using the recovered exhaust heat. It should be noted that theexpander clutch 35 may be provided at any intermediate position of a power transmission path from theengine 2 to therefrigerant pump 32 and theexpander 37. - The refrigerant from the
refrigerant pump 32 is supplied to theheat exchanger 36 via therefrigerant passage 41. Theheat exchanger 36 is a heat exchanger for performing heat exchange between the cooling water of theengine 2 and the refrigerant and evaporating and overheating the refrigerant. - The refrigerant from the
heat exchanger 36 is supplied to theexpander 37 via therefrigerant passage 42. Theexpander 37 is a steam turbine for converging heat into rotational energy by expanding the evaporated and overheated refrigerant. The power recovered by theexpander 37 drives therefrigerant pump 32 and is transmitted to theengine 2 via a belt transmission mechanism to assist the rotation of theengine 2. - The refrigerant from the
expander 37 is supplied to thecondenser 38 viarefrigerant passages condenser 38 is a heat exchanger for performing heat exchange between outside air and the refrigerant and cooling and liquefying the refrigerant. Thus, thecondenser 38 is arranged in parallel with theradiator 11 and cooled by aradiator fan 12. Thecondenser 38 is mounted on the vehicle body. - The
refrigerant passage 43 a is connected to theexpander 37. Therefrigerant passage 43 b connects therefrigerant passage 43 a and thecondenser 38. Therefrigerant passages refrigeration cycle junction 46 to be described later. - The
refrigerant passage 43 a connecting theengine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than therefrigerant passage 43 b to absorb a relative displacement caused by vibration. High flexibility means low rigidity and being freely deformable. To provide flexibility, the flexible pipe has a bellows-like shape or is made of a material which is soft and excellent in flexibility. Thus, therefrigerant passage 43 a can be freely bent at any intermediate position and can absorb vibration if the vibration is transmitted. A part of therefrigerant passage 43 a on the side of theexpander 37 mounted on theengine 2 vibrates together with theengine 2 and theexpander 37. - The
refrigerant passage 43 b is a pipe connected to thecondenser 38 and having lower flexibility, i.e. higher rigidity than therefrigerant passage 43 a such as a stainless steel pipe or an aluminum pipe. Therefrigerant passage 43 b vibrates together with thecondenser 38 mounted on the vehicle body. - The
refrigerant passage 43 a is connected to theexpander 37 mounted on theengine 2. Further, therefrigerant passage 43 b is connected to thecondenser 38 mounted on the vehicle body. Thus, when the vehicle is driven, a vibration frequency of therefrigerant passage 43 a and that of therefrigerant passage 43 b differ. In the present embodiment, therefrigerant passage 43 a is formed by a flexible pipe for refrigerant, whereby a vibrational difference between the part of therefrigerant passage 43 a on the side of theengine 2 and therefrigerant passage 43 b is absorbed by therefrigerant passage 43 a. - The refrigerant liquefied by the
condenser 38 is returned to therefrigerant pump 32 viarefrigerant passages refrigerant pump 32 is fed to theheat exchanger 36 again by therefrigerant pump 32 and circulates through each constituent element of theRankine cycle 31. - The
refrigerant passage 44 a is connected to thecondenser 38. Therefrigerant passage 44 b connects therefrigerant passage 43 a and therefrigerant pump 32. Therefrigerant passages refrigeration cycle junction 45 to be described later. - The
refrigerant passage 44 a is, for example, a stainless steel pipe or an aluminum pipe having lower flexibility than therefrigerant passage 44 b. Therefrigerant passage 44 a vibrates together with thecondenser 38. - The
refrigerant passage 44 b connecting theengine 2 side component and the vehicle body side component is a flexible pipe for refrigerant having higher flexibility than therefrigerant passage 44 a to absorb a relative displacement caused by vibration. A part of therefrigerant passage 44 b on the side of theengine 2 vibrates together with theengine 2 by having the vibration of theengine 2 transmitted thereto. - By forming the
refrigerant passage 44 b by the flexible pipe for refrigerant, a vibrational difference between therefrigerant passages refrigerant passage 44 b. - Next, the
refrigeration cycle 51 is described. Since therefrigeration cycle 51 shares the refrigerant circulating in theRankine cycle 31, therefrigeration cycle 51 is integrated with theRankine cycle 31 and the configuration thereof is simple. Specifically, therefrigeration cycle 51 includes acompressor 52, thecondenser 38 and anevaporator 55. - The
compressor 52 is a fluid machine for compressing the refrigerant of therefrigeration cycle 51 at high temperature and high pressure. Thecompressor 52 is mounted on the vehicle body. Thecompressor 52 is an electric compressor and power is supplied thereto from an unillustrated battery or the like. - The refrigerant from the
compressor 52 is supplied to thecondenser 38 via therefrigerant passage 43 b after joining therefrigerant passage 43 a at therefrigeration cycle junction 46 via arefrigerant passage 56. Therefrigerant passage 56 is formed by a general metal pipe (steel pipe) having relatively high rigidity. Thecondenser 38 is a heat exchanger for condensing and liquefying the refrigerant by heat exchange with outside air. The liquid refrigerant from thecondenser 38 is supplied to theevaporator 55 via arefrigerant passage 57 branched off from therefrigerant passage 44 a at therefrigeration cycle junction 45. Therefrigerant passage 57 is also formed by a general metal pipe (steel pipe) having relatively high rigidity. Theevaporator 55 is arranged in a case of an air conditioning unit in the same manner as an unillustrated heater core. Theevaporator 55 is a heat exchanger for evaporating the liquid refrigerant from thecondenser 38 and cooling air conditioning air from a blower fan by latent heat of evaporation. - The refrigerant evaporated by the
evaporator 55 is returned to thecompressor 52 via arefrigerant passage 58. It should be noted that a mixing ratio of the air conditioning air cooled by theevaporator 55 and that heated by the heater core is changed according to an opening of an air mix door to adjust the temperature to a temperature set by a passenger. - The
integrated cycle 30 composed of theRankine cycle 31 and therefrigeration cycle 51 appropriately includes various valves at intermediate positions of the circuit to control the refrigerant flowing in the cycle. For example, to control the refrigerant circulating in theRankine cycle 31, a pumpupstream valve 61 is provided in therefrigerant passage 44 b allowing communication between therefrigeration cycle junction 45 and therefrigerant pump 32 and an expanderupstream valve 62 is provided in therefrigerant passage 42 allowing communication between theheat exchanger 36 and theexpander 37. Further, acheck valve 63 for preventing a reverse flow of the refrigerant from theheat exchanger 36 to therefrigerant pump 32 is provided in therefrigerant passage 41 allowing communication between therefrigerant pump 32 and theheat exchanger 36. Acheck valve 64 for preventing a reverse flow of the refrigerant from therefrigeration cycle junction 46 to theexpander 37 is also provided in therefrigerant passage 43 a allowing communication between theexpander 37 and therefrigeration cycle junction 46. Further, anexpander bypass passage 65 is provided which bypasses theexpander 37 from a side upstream of the expanderupstream valve 62 and joins at a side upstream of thecheck valve 64, and abypass valve 66 is provided in thisexpander bypass passage 65. Furthermore, apressure regulating valve 68 is provided in apassage 67 bypassing thebypass valve 66. Also in therefrigeration cycle 51, an airconditioning circuit valve 69 is provided in therefrigerant passage 57 connecting therefrigeration cycle junction 45 and theevaporator 55. - Any of the above four
valves engine controller 71 are input a signal indicating a pressure upstream of the expander detected by apressure sensor 72, a signal indicating a refrigerant pressure Pd at the exit of thecondenser 38 detected by apressure sensor 73, a rotation speed signal of theexpander 37, etc. In theengine controller 71, thecompressor 52 of therefrigeration cycle 51 and theradiator fan 12 are controlled and the opening and closing of the above four electromagnetic on-offvalves - For example, an expander torque (regenerative power) is predicted based on the pressure upstream of the expander detected by the
pressure sensor 72 and the expander rotation speed, and theexpander clutch 35 is engaged when this predicted expander torque is positive (the rotation of the engine output shaft can be assisted) and released when the predicted expander torque is zero or negative. The expander torque can be predicted with high accuracy based on the sensor detected pressure and the expander rotation speed as compared with the case where the expander torque (regenerative power) is predicted from the exhaust temperature, and theexpander clutch 35 can be properly engaged/released according to a generation state of the expander torque (for further details, see JP2010-190185A). - The above four on-off
valves check valves FIG. 3 . - In
FIG. 3 , the pumpupstream valve 61 is for preventing an uneven distribution of the refrigerant (containing a lubricant component) to theRankine cycle 31 by being closed under a predetermined condition that makes the refrigerant easily unevenly distributed to the circuit of theRankine cycle 31 as compared with the circuit of therefrigeration cycle 51 such as during the stop of theRankine cycle 31, and closes the circuit of theRankine cycle 31 in cooperation with thecheck valve 64 downstream of theexpander 37 as described later. The expanderupstream valve 62 cuts off therefrigerant passage 42 when a refrigerant pressure from theheat exchanger 36 is relatively low, so that the refrigerant from theheat exchanger 36 can be maintained until a high pressure is reached. This can prompt the heating of the refrigerant even if the expander torque cannot be sufficiently obtained and can shorten a time, for example, until theRankine cycle 31 is restarted (regeneration comes to be actually performed). Thebypass valve 66 is for shortening a start-up time of theRankine cycle 31 by being opened to actuate therefrigerant pump 32 after theexpander 37 is bypassed such as when an amount of the refrigerant present on the side of theRankine cycle 31 is insufficient such as at the start-up of theRankine cycle 31. If a state where the refrigerant temperature at the exit of thecondenser 38 or at the entrance of therefrigerant pump 32 is reduced from a boiling point in consideration of a pressure at that location by a predetermined temperature difference (subcool temperature SC) or more is realized by actuating therefrigerant pump 32 after theexpander 37 is bypassed, a state is prepared where the liquid refrigerant can be sufficiently supplied to theRankine cycle 31. - The
check valve 63 upstream of theheat exchanger 36 is for maintaining the refrigerant supplied to theexpander 37 at a high pressure in cooperation with thebypass valve 66, thepressure regulating valve 68 and the expanderupstream valve 62. Under a condition that the regeneration efficiency of the Rankine cycle is low, the operation of the Rankine cycle is stopped and the circuit is closed in a section before and after the heat exchanger, whereby the refrigerant pressure during the stop is increased so that the Rankine cycle can be quickly restarted utilizing the high-pressure refrigerant. Thepressure regulating valve 68 functions as a relief valve for allowing the refrigerant having reached an excessively high pressure to escape by being opened when the pressure of the refrigerant supplied to theexpander 37 becomes excessively high. - The
check valve 64 downstream of theexpander 37 is for preventing an uneven distribution of the refrigerant to theRankine cycle 31 in cooperation with the aforementioned pumpupstream valve 61. If theengine 2 is not warm yet immediately after the operation of thehybrid vehicle 1 is started, the temperature of theRankine cycle 31 is lower than that of therefrigeration cycle 51 and the refrigerant may be unevenly distributed toward theRankine cycle 31. Although a probability of uneven distribution toward theRankine cycle 31 is not very high, there is a request to resolve even a slightly uneven distribution of the refrigerant to secure the refrigerant of therefrigeration cycle 51, for example, immediately after the start of the vehicle operation in summer since it is wished to quickly cool vehicle interior and cooling capacity is required most. Accordingly, thecheck valve 64 is provided to prevent the uneven distribution of the refrigerant toward theRankine cycle 31. - The
compressor 52 is not so structured that the refrigerant can freely pass when the drive is stopped, and can prevent an uneven distribution of the refrigerant to therefrigeration cycle 51 in cooperation with the airconditioning circuit valve 69. This is described. When the operation of therefrigeration cycle 51 is stopped, the refrigerant moves from theRankine cycle 31 that is in steady operation and has a relatively high temperature to therefrigeration cycle 51, whereby the refrigerant circulating in theRankine cycle 31 may become insufficient. In therefrigeration cycle 51, the temperature of theevaporator 55 is low immediately after the cooling is stopped and the refrigerant tends to stay in theevaporator 55 that has a relatively large volume and a low temperature. In this case, the uneven distribution of the refrigerant to therefrigeration cycle 51 is prevented by stopping the drive of thecompressor 52 to block a movement of the refrigerant from thecondenser 38 to theevaporator 55 and closing the airconditioning circuit valve 69. - Next,
FIG. 5 is a schematic perspective view of theengine 2 showing an entire package of theengine 2. What is characteristic inFIG. 5 is that theheat exchanger 36 is arranged vertically above theexhaust manifold 4. That is, theheat exchanger 36 is mounted on theengine 2. By arranging theheat exchanger 36 in a space vertically above theexhaust manifold 4, the mountability of theRankine cycle 31 on theengine 2 is improved. Further, atension pulley 8 is provided on theengine 2. - Next, a basic operation method of the
Rankine cycle 31 is described with reference toFIGS. 7A and 7B . - First,
FIGS. 7A and 7B are graphs showing operating regions of theRankine cycle 31.FIG. 7A shows the operating region of theRankine cycle 31 when a horizontal axis represents outside air temperature and a vertical axis represents engine water temperature (cooling water temperature) andFIG. 7B shows the operating region of theRankine cycle 31 when a horizontal axis represents engine rotation speed and a vertical axis represents engine torque (engine load). - In both
FIGS. 7A and 7B , theRankine cycle 31 is operated when a predetermined condition is satisfied. TheRankine cycle 31 is operated when both of these conditions are satisfied. InFIG. 7A , the operation of theRankine cycle 31 is stopped in a region on a low water temperature side where the warm-up of theengine 2 is prioritized and a region on a high outside temperature side where a load of thecompressor 52 increases. During the warm-up in which exhaust temperature is low and recovery efficiency is poor, the cooling water temperature is quickly increased rather by not operating theRankine cycle 31. During a high outside temperature period in which high cooling capacity is required, theRankine cycle 31 is stopped to provide therefrigeration cycle 51 with sufficient refrigerant and the cooling capacity of thecondenser 38. InFIG. 7B , the operation of theRankine cycle 31 is stopped in the EV running region and a region on a high rotation speed side where the friction of theexpander 37 increases since the vehicle is thehybrid vehicle 1. Since it is difficult to provide theexpander 37 with a highly efficient structure having little friction at all the rotation speeds, theexpander 37 is so configured (dimensions and the like of each part of theexpander 37 are set) in the case ofFIG. 7B as to realize small friction and high efficiency in an engine rotation speed region where an operation frequency is high. - Effects of the first embodiment of the present invention are described.
-
FIG. 8 diagrammatically shows a state of pipes of theintegrated cycle 30 of the first embodiment. As described above, each of therefrigerant pump 32, theheat exchanger 36 and theexpander 37 of theRankine cycle 31 is mounted on theengine 2 and thecondenser 38 is mounted on the vehicle body. Therefrigerant pump 32 and theheat exchanger 36, and theheat exchanger 36 and theexpander 37 are connected by general metal pipes (steel pipes) 101 having relatively high rigidity. Theexpander 37 and thecondenser 38, and thecondenser 38 and therefrigerant pump 32 are connected by passages (conduits) having high flexibility and including aflexible pipe 100 at least in an intermediate part. This causes theflexible pipes 100 to absorb vibrational differences (changes in relative positions) between theexpander 37 and therefrigerant pump 32 mounted on theengine 2 and thecondenser 38 mounted on the vehicle body, thereby enhancing component reliability or suppressing the transmission of unpleasant vibration to passengers. - Particularly, the present embodiment is not only configured to be able to drive the
refrigerant pump 32 by theengine 2 by mounting therefrigerant pump 32 on theengine 2, but also configured to be able to drive therefrigerant pump 32 by a regenerative output of theexpander 37 by mounting theexpander 37 on theengine 2, and energy efficiency can be improved by enabling therefrigerant pump 32 to be driven also utilizing the regenerative output of theexpander 37 while increasing a degree of freedom in the operation of theRankine cycle 31 by enabling therefrigerant pump 32 to be driven by the power of theengine 2. Since theheat exchanger 36 provided between therefrigerant pump 32 and theexpander 37 is mounted on theengine 2 under such an assumption, therefrigerant pump 32 and theheat exchanger 36, and theheat exchanger 36 and theexpander 37 can be connected by the passages (conduits) 101 having relatively high rigidity, and only theexpander 37 and thecondenser 38, and thecondenser 38 and therefrigerant pump 32 are connected by theflexible pipes 100 having high flexibility. This can suppress cost by reducing the number of the relatively expensiveflexible pipes 100. Specifically, only twoflexible pipes 100 are provided at intermediate positions of the circuit of theRankine cycle 31. - Specifically, at least a part of the
refrigerant passage 43 a connected to theexpander 37 mounted on theengine 2 is formed by a flexible pipe for refrigerant having higher flexibility than therefrigerant passage 43 b connected to thecondenser 38 mounted on the vehicle body. This enables therefrigerant passage 43 a to absorb a vibrational difference between the part of therefrigerant passage 43 a on the side of theengine 2 and therefrigerant passage 43 b. Further, therefrigerant passage 43 b can be formed by a metal pipe less expensive than the flexible pipe for refrigerant such as a copper pipe, a stainless steel pipe or an aluminum pipe, and the number of the expensive flexible pipes for refrigerant can be reduced. Thus, the cost of theintegrated cycle 30 can be reduced. - By using the flexible pipe for refrigerant at least in a part of the
refrigerant passage 43 a, the length of the pipe connecting theexpander 37 and thecondenser 38 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of theintegrated cycle 30 can be improved. - At least a part of the
refrigerant passage 44 b connected to therefrigerant pump 32 mounted on theengine 2 is formed by a flexible pipe for refrigerant having higher flexibility than therefrigerant passage 44 a connected to thecondenser 38. This enables therefrigerant passage 44 b to absorb a vibrational difference between therefrigerant passage 44 a and the part of therefrigerant passage 44 b on the side of theengine 2. Further, therefrigerant passage 44 a can be formed by a metal pipe less expensive than the flexible pipe for refrigerant, and the number of the expensive flexible pipes for refrigerant can be reduced. Thus, the cost of theintegrated cycle 30 can be reduced. - By using the flexible pipe for refrigerant at least in a part of the
refrigerant passage 43 a, the length of the pipe connecting thecondenser 38 and therefrigerant pump 32 can be shortened, a pressure loss in the pipe can be reduced and the efficiency of theintegrated cycle 30 can be improved. - By forming the
refrigerant passage 43 a by a flexible pipe for refrigerant and forming therefrigerant passage 43 b, for example, by a metal pipe in theintegrated cycle 30 in which the output shaft of theexpander 37 and that of theengine 2 are configured to be able to transmit power, the above effects can be obtained more. - Next, a second embodiment of the present invention is described using
FIGS. 9 and 10 . -
FIG. 9 is a schematic configuration diagram of a hybrid vehicle in the present embodiment.FIG. 10 is a schematic configuration diagram of an integrated cycle in the present embodiment. The second embodiment is described, centering on parts different from the first embodiment. The same configuration as the first embodiment is denoted by the same reference signs as in the first embodiment and not described here. - A
compressor 59 is mounted on anengine 2 and driven by theengine 2. As shown inFIG. 9 , acompressor pulley 53 is fixed to a drive shaft of thecompressor 59 and abelt 34 is mounted on thiscompressor pulley 53 and acrank pulley 2 a. A drive force of theengine 2 is transmitted to thecompressor pulley 53 via thisbelt 34 to drive thecompressor 59. Further, anelectromagnetic clutch 54 is provided between thecompressor pulley 53 and thecompressor 59 to make thecompressor 59 and thecompressor pulley 53 connectable to and disconnectable from each other. - A
refrigerant passage 56 connected to thecompressor 59 is a flexible pipe for refrigerant having higher flexibility than arefrigerant passage 43 b. - A
refrigerant passage 58 provided between thecompressor 59 and anevaporator 55 and connected to thecompressor 59 is a flexible pipe for refrigerant similarly to therefrigerant passage 56. - When the
compressor 59 is mounted on theengine 2, a vibration frequency of therefrigerant passage 56 connected to thecompressor 59 and that of therefrigerant passage 43 b connected to acondenser 38 differ when the vehicle is driven. In the present embodiment, a vibrational difference between therefrigerant passages refrigerant passage 56 by the flexible pipe for refrigerant. - Effects of the second embodiment of the present invention are described.
-
FIG. 11 diagrammatically shows a state of pipes of theintegrated cycle 30 of the second embodiment. A difference from the first embodiment is that the refrigerant passages before and after thecompressor 59 are formed byflexible pipes 100 since thecompressor 59 is mounted on theengine 2. Also according to the second embodiment, cost can be suppressed by reducing the number of relatively expensiveflexible pipes 100. Specifically, only twoflexible pipes 100 are provided at intermediate positions of a circuit of aRankine cycle 31 and the number of theflexible pipes 100 is suppressed to four in the entireintegrated cycle 30. - Specifically, at least a part of the
refrigerant passage 56 is formed by the flexible pipe for refrigerant and therefrigerant passage 56 is connected to therefrigerant passage 43 b at arefrigeration cycle junction 46. This enables therefrigerant passage 43 b to absorb a vibrational difference between therefrigerant passages - Next, a third embodiment of the present invention is described.
- The third embodiment is described, centering on parts different from the second embodiment.
- In the third embodiment, a
refrigerant passage 43 b is formed by a flexible pipe having higher flexibility thanrefrigerant passages refrigerant passages - Effects of the third embodiment of the present invention are described.
-
FIG. 12 diagrammatically shows a state of pipes of anintegrated cycle 30 of the third embodiment. A difference from the second embodiment is that a pipe connecting anexpander 37 and acondenser 38 and a pipe connecting acompressor 59 and thecondenser 38 join each other at an intermediate position and a part after the junction is formed by aflexible pipe 100. Also according to the third embodiment, cost can be suppressed by reducing the number of relatively expensiveflexible pipes 100. Specifically, only twoflexible pipes 100 are provided at intermediate positions of a circuit of aRankine cycle 31 and the number of theflexible pipes 100 is suppressed to three in the entireintegrated cycle 30. - Specifically, a
refrigerant passage 43 b connected to thecondenser 38 is formed by a flexible pipe for refrigerant, and arefrigerant passage 43 a connected to theexpander 37 and arefrigerant passage 56 connected to thecompressor 59 are formed, for example, by stainless pipes or aluminum pipes less expensive than flexible pipes for refrigerant. This enables the absorption of a vibrational difference between therefrigerant passage 43 b and therefrigerant passages refrigerant passages integrated cycle 30 can be reduced. - It should be noted that a
refrigerant passage 44 a may be formed by a flexible pipe for refrigerant and arefrigerant passage 44 b may be formed by a stainless steel pipe or an aluminum pipe. - By using flexible pipes for refrigerant at least as some of the refrigerant passages, the length of the pipes connecting the
expander 37 or thecompressor 59 and thecondenser 38 and the pipe connecting thecondenser 38 and arefrigerant pump 32 can be shortened, a pressure loss in the pipes can be reduced and the efficiency of theintegrated cycle 30 can be improved. - The present invention is not limited to the above embodiments. For example, a pipe configured to include a flexible pipe for refrigerant having high flexibility in a part (at an intermediate position) of a general metal pipe may be used as a passage pipe having high flexibility to absorb a relative displacement caused by vibration.
- Although the embodiments of the present invention have been described above, the above embodiments are only an illustration of some application examples of the present invention and not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.
- This application claims a priority of Japanese Patent Application No. 2011-216772 filed with the Japan Patent Office on Sep. 30, 2011, all the contents of which are hereby incorporated by reference.
Claims (9)
1. A Rankine cycle system, comprising:
a refrigerant pump which is mounted on an engine and is configured to feed refrigerant;
a heat exchanger which is mounted on the engine and is configured to recover exhaust heat of the engine to the refrigerant;
an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger; and
a condenser which is mounted on a vehicle body and condenses the refrigerant expanded by the expander; wherein
the expander and the condenser, and the condenser and the refrigerant pump are connected by flexible pipes having higher flexibility than other pipes.
2. The Rankine cycle system according to claim 1 , comprising:
a refrigeration cycle which is configured to share the condenser and the refrigerant; wherein
a compressor provided in the refrigeration cycle is mounted on the engine, a pipe between the expander and the condenser and a pipe between the compressor and the condenser are joined in a state where the pipes are supported on the engine, and a junction and the condenser are connected by a flexible pipe.
3. The Rankine cycle system according to claim 1 , wherein an output shaft of the expander and an engine output shaft are configured to be able to transmit power.
4. A Rankine cycle system, comprising:
a heat exchanger which is mounted on an engine and is configured to recover exhaust heat of the engine to refrigerant;
an expander which is mounted on the engine and is configured to convert the exhaust heat recovered to the refrigerant into power by expanding the refrigerant whose temperature has been increased by the heat exchanger;
a condenser which is mounted on a vehicle body and is configured to condense the refrigerant expanded by the expander;
a refrigeration cycle of an air conditioner which is configured to share the condenser and the refrigerant;
a first pipe which is connected to the expander; and
a third pipe which is connected to the first pipe and a second pipe connected to a compressor of the refrigeration cycle and is configured to introduce the refrigerant to the condenser; wherein
either one of the first and third pipes has higher flexibility than the other.
5. The Rankine cycle system according to claim 4 , wherein
the compressor is mounted on the vehicle body; and
the first pipe has higher flexibility than the second and third pipes.
6. The Rankine cycle system according to claim 4 , wherein
the compressor is mounted on the engine; and
the first and second pipes have higher flexibility than the third pipe.
7. The Rankine cycle system according to claim 4 , wherein
the compressor is mounted on the engine; and
the third pipe has higher flexibility than the first and second pipes.
8. The Rankine cycle system according to claim 4 , comprising:
a refrigerant pump which is configured to supply the refrigerant condensed by the condenser to the heat exchanger;
a fourth pipe which is connected to the refrigerant pump; and
a sixth pipe which is connected to the fourth pipe and a fifth pipe connected to an evaporator of the refrigeration cycle and in which the refrigerant discharged from the condenser flows; wherein
either one of the fourth and sixth pipes has higher flexibility than the other.
9. The Rankine cycle system according to claim 4 , wherein
an output shaft of the expander and an output shaft of the engine are configured to be able to transmit power.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-216772 | 2011-09-30 | ||
JP2011216772A JP2013076373A (en) | 2011-09-30 | 2011-09-30 | Rankine cycle system |
PCT/JP2012/072725 WO2013047139A1 (en) | 2011-09-30 | 2012-09-06 | Rankine cycle system |
Publications (1)
Publication Number | Publication Date |
---|---|
US20140174087A1 true US20140174087A1 (en) | 2014-06-26 |
Family
ID=47995179
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/233,204 Abandoned US20140174087A1 (en) | 2011-09-30 | 2012-09-06 | Rankine cycle system |
Country Status (5)
Country | Link |
---|---|
US (1) | US20140174087A1 (en) |
EP (1) | EP2762688A4 (en) |
JP (1) | JP2013076373A (en) |
CN (1) | CN103797218A (en) |
WO (1) | WO2013047139A1 (en) |
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US20140208754A1 (en) * | 2011-09-30 | 2014-07-31 | Nissan Motor Co., Ltd. | Rankine cycle |
US20140224469A1 (en) * | 2013-02-11 | 2014-08-14 | Access Energy Llc | Controlling heat source fluid for thermal cycles |
US20150047351A1 (en) * | 2011-09-30 | 2015-02-19 | Takayuki Ishikawa | Waste heat utilization apparatus |
US20150360539A1 (en) * | 2014-06-11 | 2015-12-17 | Hyundai Motor Company | Heating system of hybrid vehicle |
CN105805850A (en) * | 2016-05-10 | 2016-07-27 | 合肥天鹅制冷科技有限公司 | All-sealed air conditioning device |
US20170001494A1 (en) * | 2013-12-16 | 2017-01-05 | Byd Company Limited | Air conditioning system, method for controlling the same and hybrid vehicle |
US9551487B2 (en) | 2012-03-06 | 2017-01-24 | Access Energy Llc | Heat recovery using radiant heat |
US20170074121A1 (en) * | 2014-03-03 | 2017-03-16 | Eaton Corporation | Coolant energy and exhaust energy recovery system |
WO2017142496A1 (en) * | 2016-02-18 | 2017-08-24 | Vural Erdal | A cooling and electricity generation system |
US20180355775A1 (en) * | 2015-11-17 | 2018-12-13 | Carrier Corporation | Temperature control of exhaust gas of a transportation refrigeration unit |
US10626754B2 (en) | 2014-08-21 | 2020-04-21 | Kobe Steel, Ltd. | Compression device |
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US20140208754A1 (en) * | 2011-09-30 | 2014-07-31 | Nissan Motor Co., Ltd. | Rankine cycle |
US20150047351A1 (en) * | 2011-09-30 | 2015-02-19 | Takayuki Ishikawa | Waste heat utilization apparatus |
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US9551487B2 (en) | 2012-03-06 | 2017-01-24 | Access Energy Llc | Heat recovery using radiant heat |
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US20170001494A1 (en) * | 2013-12-16 | 2017-01-05 | Byd Company Limited | Air conditioning system, method for controlling the same and hybrid vehicle |
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US10160288B2 (en) * | 2014-06-11 | 2018-12-25 | Hyundai Motor Company | Heating system of hybrid vehicle |
US10626754B2 (en) | 2014-08-21 | 2020-04-21 | Kobe Steel, Ltd. | Compression device |
US20180355775A1 (en) * | 2015-11-17 | 2018-12-13 | Carrier Corporation | Temperature control of exhaust gas of a transportation refrigeration unit |
US10704438B2 (en) * | 2015-11-17 | 2020-07-07 | Carrier Corporation | Temperature control of exhaust gas of a transportation refrigeration unit |
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CN105805850A (en) * | 2016-05-10 | 2016-07-27 | 合肥天鹅制冷科技有限公司 | All-sealed air conditioning device |
Also Published As
Publication number | Publication date |
---|---|
JP2013076373A (en) | 2013-04-25 |
EP2762688A4 (en) | 2015-03-04 |
WO2013047139A1 (en) | 2013-04-04 |
EP2762688A1 (en) | 2014-08-06 |
CN103797218A (en) | 2014-05-14 |
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