JP2013160076A - Rankine cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Rankine cycle device in which a regeneration amount of waste heat is increased and thermal efficiency is improved as a heat engine.SOLUTION: A Rankine cycle device comprises: a steam generator 21 which generates the steam of a hydraulic fluid; an expander 22 which expands the steam of the hydraulic fluid; a condenser 23 which condenses the hydraulic fluid flowing out of the expander 22; a pump for pressure-feeding the hydraulic fluid that flows out of the condenser 23 to the steam generator 21; and a hydraulic fluid circuit successively connecting the steam generator 21, the expander 22, the condenser 23 and the pump. In the Rankine cycle device, the condenser 23 performs heat exchange between cooling water at a downstream side of a radiator 12 that cools the cooling water of an internal combustion engine and the hydraulic fluid.

Description

  The present invention relates to a Rankine cycle device, and in particular, a steam generator that generates steam of a working fluid, an expander that expands the steam, a condenser that condenses the working fluid, and a working fluid that flows out of the condenser. The present invention relates to a Rankine cycle apparatus including a pump that pumps the steam to the steam generator, and a working fluid circuit that sequentially connects the steam generator, the expander, the condenser, and the pump.

As a prior art of the Rankine cycle apparatus, for example, the Rankine cycle disclosed in Patent Document 1 is known.
The Rankine cycle disclosed in Patent Document 1 includes a steam generator, an expander, and a heat exchanger.
The steam generator generates steam using the combustion gas discharged from the engine as a heat source, and the expander expands the steam generated by the steam generator.
The heat exchanger performs heat exchange between the working fluid that has been expanded by the expander and the engine coolant circulating in the engine coolant circuit, and condenses the working fluid.

The Rankine cycle has a radiator that exchanges heat between the engine coolant and the atmosphere.
In this Rankine cycle, a radiator and a heat exchanger are arranged in parallel to the flow of engine cooling water.

JP 2005-42618 A

  However, according to the Rankine cycle disclosed in Patent Document 1, since the working fluid is condensed using high-temperature engine cooling water after engine cooling in the heat exchanger, the condensation pressure increases, Since heat efficiency is low, there is a problem that the amount of regenerated waste heat is small.

  The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a Rankine cycle device that can increase the amount of regenerated waste heat and has high thermal efficiency as a heat engine.

  In order to solve the above problems, the present invention condenses a steam generator that generates steam of a working fluid, an expander that expands the steam of the working fluid, and the working fluid that flows out of the expander. Rankine cycle apparatus comprising a condenser, a pump for pumping the working fluid flowing out of the condenser to the steam generator, and a working fluid circuit for sequentially connecting the steam generator, the expander, the condenser and the pump The condenser is characterized in that heat is exchanged between the cooling water downstream of the radiator for cooling the cooling water of the internal combustion engine and the working fluid.

  According to the present invention, in the condenser, heat exchange between the low-temperature cooling water cooled in the radiator and the working fluid is performed, so that the condensation pressure is reduced and the heat efficiency as the heat engine is high. The amount can be increased.

Further, in the Rankine cycle device, the condenser in the working fluid circuit is a primary condenser, a secondary condenser is provided downstream of the primary condenser, and the working fluid flowing out from the primary condenser is It is good also as a structure condensed with a secondary condenser.
In this case, since the secondary condenser condenses the working fluid flowing out from the primary condenser, the amount of regeneration can be increased.
Further, even when the temperature of the cooling water is high and the amount of refrigerant condensed by the primary condenser is small, the amount of waste heat regenerated can be increased by the condensation by the secondary condenser.

In the Rankine cycle device, the heat source of the steam generator may be cooling water upstream of the radiator.
In this case, the temperature of the cooling water flowing into the condenser can be lowered by using the heat source of the steam generator as the cooling water upstream of the radiator.

In the Rankine cycle apparatus, the heat source of the steam generator may be configured to use EGR gas waste heat or oil cooler oil waste heat.
In this case, the waste heat of EGR gas or the waste heat of oil in the oil cooler, which has conventionally been waste heat to the coolant other than the internal combustion engine, can be used to further reduce the temperature of the coolant flowing into the condenser. Can do.
In the Rankine cycle device, the working fluid circuit includes a bypass channel connecting the upstream side of the primary condenser and the upstream side of the secondary condenser, the primary condenser, and the bypass channel. It is good also as a structure provided with the flow control valve which controls the flow volume which flows.
In this case, when the temperature of the cooling water is equal to or higher than a predetermined value, it is possible to prevent the working fluid from being heated by the high-temperature cooling water by flowing the working fluid through the bypass flow path by the flow rate control valve.

  ADVANTAGE OF THE INVENTION According to this invention, the Rankine-cycle apparatus with much regeneration amount of waste heat and favorable thermal efficiency as a heat engine can be provided.

It is a mimetic diagram of a Rankine cycle device concerning a 1st embodiment. It is a mimetic diagram of a Rankine cycle device concerning a 2nd embodiment. It is a schematic diagram of the Rankine cycle apparatus which concerns on 3rd Embodiment.

(First embodiment)
Hereinafter, the Rankine cycle device according to the first embodiment will be described with reference to FIG.
The Rankine cycle device of the present embodiment is a vehicle-mounted Rankine cycle device mounted on a vehicle.
As shown in FIG. 1, the vehicle includes an engine 11, a radiator 12, and a pump 13, and includes a cooling water circuit 10 that circulates cooling water for engine cooling.
In addition, the Rankine cycle apparatus includes a steam generator 21, an expander 22, a primary condenser 23, a secondary condenser 26, and a refrigerant pump 27, and includes a refrigerant circuit 20 that circulates refrigerant.

The cooling water circuit 10 will be described.
The engine 11 as an internal combustion engine is a traveling drive source that generates a driving force for traveling the vehicle.
The engine 11 is cooled by cooling water circulating in the cooling water circuit 10.
The cooling water circulating through the cooling water circuit 10 is a known cooling water, and uses an antifreeze (LLC).
The radiator 12 is a radiator for cooling water that exchanges heat between the cooling water used for cooling the engine 11 and the atmosphere, and includes an electric blower fan 14 that generates cooling air.

The cooling water circuit 10 of the present embodiment includes a first flow path 15 that connects the cooling water outlet of the engine 11 and the cooling water inlet of the radiator 12, and a first flow path that connects the cooling water outlet of the radiator 12 and the cooling water inlet of the engine 11. Two flow paths 16 are provided.
A pump 13 is provided in the second flow path 16 that connects the cooling water outlet of the radiator 12 and the cooling water inlet of the engine 11.
The pump 13 is driven using the driving force of the engine 11 and circulates the cooling water in one direction in the cooling water circuit 10.
The cooling water circuit 10 includes a bypass flow path 17 that bypasses the cooling water flowing out from the engine 11 and returns it to the engine 11 without passing through the radiator 12, and the bypass flow path 17 starts from the branch point A of the first flow path 15. The junction B of the second flow path 16 is connected.

In the present embodiment, a thermostat 18 is provided at the junction B of the second flow path 16.
The thermostat 18 adjusts the flow rate of the cooling water flowing from the engine 11 to the bypass flow path 17 and the flow rate of the cooling water passing through the radiator 12.
By adjusting the flow rate of the cooling water in the thermostat 18, the temperature of the engine 11 can be kept within an appropriate temperature range.

The thermostat 18 adjusts the flow ratio of the cooling water to be passed to the radiator 12 and the cooling water to be passed to the bypass flow path 17, and can also pass all the cooling water to the radiator 12 or allow all the cooling water to pass to the bypass passage. Is possible.
The control device 28 is connected to the water temperature sensor 19, and the water temperature sensor 19 detects the temperature of the cooling water flowing into the engine 11.
The control device 28 controls driving of the blower fan 14 of the radiator 12.

Next, the refrigerant circuit 20 will be described.
The refrigerant circuit 20 through which the refrigerant as the working fluid flows corresponds to the working fluid circuit.
The refrigerant circuit 20 of the Rankine cycle device of the present embodiment sequentially connects a steam generator 21, an expander 22, a primary condenser 23, a secondary condenser 26, and a refrigerant pump 27.
The refrigerant in the refrigerant circuit 20 flows through the refrigerant circuit 20 along the arrangement order of the steam generator 21, the expander 22, the primary condenser 23, the secondary condenser 26, and the refrigerant pump 27.
The direction in which the refrigerant flows in the refrigerant circuit 20 is the refrigerant circulation direction.

The refrigerant circuit 20 uses a refrigerant based on a skeleton made of fluorocarbon.
In the present embodiment, HFC134a (R134a) is used as a refrigerant based on a skeleton made of fluorocarbon.
In the Rankine cycle device of the present embodiment, the lubricating oil circulates through the refrigerant circuit 20 together with the refrigerant.
The lubricating oil circulating in the refrigerant circuit 20 performs functions such as lubrication, sealing, and cooling in the sliding portions of the expander 22 and the refrigerant pump 27.

The steam generator 21 is a means for generating refrigerant vapor using the exhaust gas discharged from the engine 11 as a heat source (not shown).
In the steam generator 21, the refrigerant is heated by heat exchange between the refrigerant and the exhaust gas to generate steam.
In the refrigerant circuit 20 of the Rankine cycle device of the present embodiment, the refrigerant outlet of the steam generator 21 is connected to the refrigerant inlet of the expander 22 via the first flow path 29.

The expander 22 has turbine blades (not shown) that are driven by high-pressure steam, and the high-pressure steam rotates the turbine blades, whereby the expander 22 obtains rotational force at the output shaft.
The expander 22 decompresses and expands the steam in a substantially adiabatic state to convert the thermal energy of the steam into mechanical energy. The output shaft of the expander 22 is connected to a generator (not shown). The rotational force obtained in the step drives the generator.
In the refrigerant circuit 20 of the Rankine cycle device of this embodiment, the refrigerant outlet of the expander 22 is connected to the refrigerant inlet of the primary condenser 23 via the second flow path 30.

The primary condenser 23 has a refrigerant passage part 24 through which the refrigerant flowing out of the expander 22 passes and a cooling water passage part 25 through which the cooling water for cooling the vapor refrigerant passes.
The cooling water passage portion 25 of the primary condenser 23 is disposed between the radiator 12 and the thermostat 18 in the second flow path 16 of the cooling water circuit 10, and the cooling water passing through the cooling water passage portion 25 passes through the radiator 12. This is the later cooling water.
The cooling water after passing through the radiator 12 is subjected to heat exchange with the atmosphere in the radiator 12 and has a lower temperature than the cooling water before passing through the radiator 12.
The steam is condensed by heat exchange between the refrigerant of the steam flowing out from the expander 22 and the cooling water after passing through the radiator 12.
In the refrigerant circuit 20 of the Rankine cycle device of the present embodiment, the refrigerant outlet of the primary condenser 23 is connected to the refrigerant inlet of the secondary condenser 26 via the third flow path 31.

The secondary condenser 26 further condenses the refrigerant that has flowed out of the primary condenser 23. In the secondary condenser 26, the refrigerant is cooled by the air and condensed by exchanging heat with the air.
That is, the secondary condenser 26 is an air-cooled condenser.
In the refrigerant circuit 20 of the Rankine cycle device according to the present embodiment, the refrigerant outlet of the secondary condenser 26 is connected to the refrigerant inlet of the steam generator 21 via the fourth flow path 32. A refrigerant pump 27 is provided.

The refrigerant pump 27 pumps the refrigerant flowing out from the secondary condenser 26 to the steam generator 21. In this embodiment, an electric pump is used.
The refrigerant pump 27 is connected to the control device 28, and the refrigerant pump 27 is driven by the control of the control device 28.
When the refrigerant pump 27 is controlled by the control device 28, the refrigerant flows in the refrigerant circuit 20 in the order in which the vapor generator 21, the expander 22, the primary condenser 23, the secondary condenser 26, and the refrigerant pump 27 are arranged. Can circulate.
The refrigerant circuit 20 is provided with a bypass passage 33 that connects the upstream side of the primary condenser 23 and the upstream side of the secondary condenser 26. A flow rate control valve 34 capable of controlling the flow rate of the refrigerant flowing through the refrigerant passage portion 24 and the bypass flow channel 33 is provided at a connection portion between the bypass flow channel 33 and the second flow channel 30. The flow rate control valve 34 is controlled by the control device 28 according to the temperature of the cooling water detected by the water temperature sensor 19.

Next, the operation of the Rankine cycle device of the present embodiment will be described.
During operation of the engine 11, the pump 13 of the cooling water circuit 10 is driven, and the cooling water of the cooling water circuit 10 is supplied to the engine 11, the radiator 12, the cooling water passage 25 of the primary condenser 23, the thermostat 18, and the pump 13. It circulates in the order.
Further, a part of the cooling water flowing out from the engine 11 passes through the bypass passage 17 and the pump 13 from the thermostat 18 without passing through the radiator 12 and the primary condenser 23.

By the way, when the engine 11 is in a low load operation state and the amount of ventilation of the radiator 12 is large, the control device 28 controls the thermostat 18 so that the engine 11 is not overcooled by the cooling water flowing into the engine 11. .
Specifically, the thermostat 18 is configured so that the amount of cooling water passing through the bypass passage 17 is increased and the amount of cooling water flowing into the radiator 12 is reduced so that the temperature of the cooling water before entering the engine 11 does not become too low. Control the flow of cooling water.
Note that when the engine 11 is in a high-load operation state and the amount of ventilation of the radiator 12 is small, the temperature of the cooling water flowing out of the radiator 12 becomes high.
The control device 28 controls the blower fan 14 of the radiator 12 so as to keep the temperature of the cooling water before entering the engine 11 within an appropriate temperature range.

During the operation of the engine 11, the refrigerant pump 27 of the refrigerant circuit 20 is driven, and the refrigerant of the refrigerant circuit 20 is supplied from the steam generator 21, the expander 22, the primary condenser 23, the secondary condenser 26, and the refrigerant pump 27. Cycles along the order.
By driving the refrigerant pump 27, high-pressure steam generated in the steam generator 21 flows into the expander 22.
The steam flowing into the expander 22 is decompressed and expanded in a substantially adiabatic state in the expander 22, and the heat energy of the steam is converted into mechanical energy and output from the output shaft of the expander 22.
The output of the expander 22 drives a generator, and electric power is obtained by the generator. ).

The vapor flowing out of the expander 22 flows into the primary condenser 23, passes through the refrigerant passage portion 24, and is condensed by heat exchange with the cooling water in the primary condenser 23.
The cooling water passing through the cooling water passage portion 25 of the primary condenser 23 is the cooling water after passing through the radiator 12, and the cooling water after passing through the radiator 12 is at a lower temperature than the cooling water before passing through the radiator 12.
For this reason, in the heat exchange between the cooling water and the refrigerant after passing through the radiator 12, the temperature difference between the cooling water and the refrigerant after passing through the radiator 12 is larger than in the heat exchange between the cooling water and the refrigerant before passing through the radiator 12. For this reason, the amount of refrigerant condensed increases. Further, since the cooling water is low in temperature, the condensation pressure of the refrigerant can be lowered.

In particular, when the engine 11 is in a low-load operation state and the air flow rate of the radiator 12 is large, the thermostat 18 controls the flow of the cooling water so as to prevent the engine 11 from being overcooled.
In this case, the thermostat 18 controls the flow rate of the cooling water so that the amount of the cooling water passing through the bypass channel 17 is increased and the cooling water flowing into the radiator 12 is reduced.
Since the cooling water passing through the radiator 12 becomes small due to the operation of the thermostat 18, the cooling water after passing through the radiator 12 is sufficiently cooled as compared with the case where there is much cooling water passing through the radiator 12. The temperature of the cooling water is greatly reduced.
For this reason, in the primary condenser 23, the amount of refrigerant condensed increases due to heat exchange between the cooling water having a low temperature and the refrigerant. Further, since the cooling water is low in temperature, the condensation pressure of the refrigerant can be lowered.

The refrigerant flowing out of the primary condenser 23 flows into the secondary condenser 26, and the refrigerant flowing into the secondary condenser 26 exchanges heat with the atmosphere.
When the refrigerant is sufficiently condensed in the primary condenser 23, the refrigerant is hardly condensed in the secondary condenser 26.
However, when the refrigerant that has not been sufficiently condensed in the primary condenser 23 flows into the secondary condenser 26, the refrigerant is condensed in the secondary condenser 26.
For example, when the engine 11 is in a high-load operation state and the amount of ventilation of the radiator 12 that cools the cooling water is small, the cooling water after passing through the radiator 12 is cooled by heat exchange with the atmosphere in the radiator 12. The temperature of the cooling water after passing through the radiator 12 is high.
As the temperature of the cooling water increases, the temperature of the cooling water and the refrigerant decreases, the amount of refrigerant condensed in the primary condenser 23 decreases, and the refrigerant is not sufficiently condensed.
When the refrigerant is not sufficiently condensed in the primary condenser 23, the secondary condenser 26 condenses the refrigerant and increases the amount of refrigerant condensed.
The refrigerant that has flowed out of the secondary condenser 26 is pumped to the steam generator 21 by the refrigerant pump 27.
When the temperature of the cooling water detected by the water temperature sensor 19 is equal to or higher than a predetermined value, the control device 28 causes the refrigerant flowing through the second flow path 30 to flow through the bypass flow path 33 by the flow rate control valve 34 to cool the high temperature. Prevents the refrigerant from being heated by water. The refrigerant flowing through the bypass flow path 33 is condensed by the secondary condenser 26.

The Rankine cycle device of the present embodiment has the following operational effects.
(1) Since the primary condenser 23 performs heat exchange between the cooling water cooled in the radiator 12 and the refrigerant, the amount of waste heat regenerated during condensation can be increased, and the thermal efficiency of the heat engine is improved. be able to.
(2) The secondary condenser 26 condenses the refrigerant flowing out from the primary condenser 23 even if the refrigerant is not sufficiently condensed in the primary condenser 23 due to the operating state of the engine 11 and the ventilation state of the radiator 12. Therefore, the amount of waste heat regenerated can be increased.
(3) Since the bypass flow path 17 and the thermostat 18 are provided, the flow rates of the cooling water passing through the radiator 12 and the primary condenser 23 and the cooling water passing through the bypass flow path 17 can be adjusted. By adjusting the flow rate of the cooling water, the engine 11 can be prevented from being overcooled, and the refrigerant can be efficiently condensed in the primary condenser 23.

(Second Embodiment)
Next, a Rankine cycle device according to the second embodiment will be described.
The Rankine cycle device according to the second embodiment is a vehicle-mounted Rankine cycle device mounted on a vehicle as in the first embodiment, but the configuration of the refrigerant circuit is different from that of the first embodiment.
In this embodiment, about the structure which is common in 1st Embodiment, description of 1st Embodiment is used and description is abbreviate | omitted and the same code | symbol is used.

As shown in FIG. 2, in the Rankine cycle device of the present embodiment, the steam generator 41 of the refrigerant circuit 40 is provided so that the cooling water flowing out from the engine 11 is used as a heat source.
The refrigerant circuit 40 connects the first flow path 44 that connects the steam generator 41 and the expander 22, the second flow path 45 that connects the expander 22 and the condenser 23, and connects the condenser 23 and the steam generator 41. A third flow path 46 is provided.
A refrigerant pump 27 is provided in the third flow path 46.
The condenser 23 of the present embodiment has the same configuration as that of the primary condenser 23 of the first embodiment, but no secondary condenser is installed in the refrigerant circuit 40.

The steam generator 41 is provided between the branch point A of the first flow path 15 in the cooling water circuit 10 and the radiator 12, and in addition to the refrigerant passage portion 42 through which the refrigerant passes, the cooling water passage portion 43 through which the cooling water passes. I have.
In the steam generator 41, steam is generated by heating the refrigerant by heat exchange between the high-temperature cooling water flowing out from the engine 11 passing through the cooling water passage portion 43 and the refrigerant passing through the refrigerant passage portion 42.

According to this embodiment, when the refrigerant pump 27 of the refrigerant circuit 40 is operated, the refrigerant of the refrigerant circuit 40 flows into the steam generator 41.
In the steam generator 41, the high-temperature cooling water that has flowed out of the operating engine 11 passes through the cooling water passage portion 43, and heat exchange between the cooling water that passes through the cooling water passage portion 43 and the refrigerant that passes through the refrigerant passage portion 42 is performed. Done.
In the steam generator 41, high-pressure refrigerant vapor is generated by heating the refrigerant with high-temperature cooling water.
The high-pressure steam flowing out from the steam generator 41 flows into the expander 22, and the steam flowing out from the expander 22 is condensed in the condenser 23 by heat exchange with the cooling water flowing out from the radiator 12.

On the other hand, the temperature of the cooling water that has passed through the steam generator 41 has decreased due to heat exchange with the refrigerant.
This cooling water flows into the radiator 12 and is further cooled by the radiator 12.
For this reason, the cooling water which flowed out of the radiator 12 turns into cooling water with a lower temperature.
And in the condenser 23, since a refrigerant | coolant is condensed by heat exchange with the cooling water with the low temperature which flowed out from the radiator 12, and a refrigerant | coolant, the condensed amount of a refrigerant | coolant increases more.
In the present embodiment, the temperature of the cooling water flowing out of the radiator 12 and flowing into the condenser 23 can be lowered by using the heat source of the steam generator 41 as the cooling water upstream of the radiator 12 in the cooling water circuit 10. In comparison with the first embodiment, the amount of waste heat regenerated can be increased.

(Third embodiment)
Next, a Rankine cycle device according to a third embodiment will be described.
The Rankine cycle device according to the third embodiment is an in-vehicle Rankine cycle device that is mounted on a vehicle as in the first embodiment, but the configuration of the refrigerant circuit is different from that of the first embodiment.
In this embodiment, about the structure which is common in 1st Embodiment, description of 1st Embodiment is used and description is abbreviate | omitted and the same code | symbol is used.

As shown in FIG. 3, in the Rankine cycle device of the present embodiment, the steam generator of the refrigerant circuit 50 is an EGR (Exhaust Gas Recirculation) cooler 51, and the EGR gas passing through the EGR cooler 51 is used as a heat source for generating steam. Is provided.
The refrigerant circuit 50 includes a first flow path 54 that connects the EGR cooler 51 and the expander 22, a second flow path 55 that connects the expander 22 and the primary condenser 23, the primary condenser 23, and the secondary condenser 26. And a fourth flow path 57 for connecting the secondary condenser 26 and the steam generator 41.
A refrigerant pump 27 is provided in the fourth flow path 57.
The refrigerant circuit 50 of the present embodiment is not provided with a bypass flow path that connects the upstream side of the primary condenser 23 and the upstream side of the secondary condenser 26 or a flow rate control valve for the bypass flow path.

The EGR cooler 51 as a steam generator includes an EGR gas passage portion 53 through which EGR gas passes, in addition to a refrigerant passage portion 52 through which the refrigerant passes.
A pipe 58 on the upstream side of the EGR gas passage 53 is connected to an exhaust manifold (not shown) provided in the engine 11, and a pipe 59 on the downstream side of the EGR gas passage 53 is connected to an intake manifold (not shown). ing.
In the EGR cooler 51, a part of the combustion gas of the engine 11 passing through the EGR gas passage portion 53 is used as EGR gas, and heat exchange between the high-temperature EGR gas and the refrigerant passing through the refrigerant passage portion 52 is performed.

According to the present embodiment, when the refrigerant pump 27 of the refrigerant circuit 50 is operated, the refrigerant in the refrigerant circuit 50 flows into the EGR cooler 51.
In the EGR cooler 51, high-temperature EGR gas, which is a part of combustion gas, from the operating engine 11 passes through the EGR gas passage portion 53, and heat exchange between the refrigerant passing through the refrigerant passage portion 52 and the EGR gas is performed.
In the EGR cooler 51, refrigerant vapor is generated by heating the refrigerant using EGR gas as a heat source.
On the other hand, the EGR gas is cooled to an appropriate temperature with the EGR gas by heat exchange with the refrigerant.
The high-pressure steam that has flowed out of the EGR cooler 51 flows into the expander 22.
In the expander 22, the thermal energy of the steam is converted into mechanical energy, and the high-pressure steam is decompressed and expanded in a substantially adiabatic state.
The steam flowing out from the expander 22 is condensed in the condenser 23 by heat exchange with the cooling water.

  Conventionally, the EGR gas is cooled by the cooling water of the engine 11 and the heat of the EGR gas is discarded in the cooling water. As a heat engine, the efficiency can be improved.

  The above embodiment shows an embodiment of the present invention, and the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the invention as described below. Is possible.

In the above embodiment, the in-vehicle Rankine cycle device mounted on the vehicle is used, but the Rankine cycle device is not limited to in-vehicle use. For example, the Rankine cycle apparatus installed on the ground may be used.
In the first embodiment, the air-cooled secondary condenser is provided in the refrigerant circuit. However, the secondary condenser is not an essential requirement and may be omitted. Moreover, even when providing a secondary condenser, not only an air cooling type but a water cooling type condenser may be used, for example.
In the third embodiment, the steam generator is an EGR cooler and the heat source is EGR gas waste heat. However, instead of the EGE cooler, the oil cooler is a steam generator, and the oil cooler oil waste heat is reduced. It is good also as a heat source. Also in this case, the heat of oil that has been discarded in the cooling water in the past can be effectively used as a heat source of the steam generator, and the efficiency as a heat engine can be improved.
In the above embodiment, the internal combustion engine is simply described as an engine, but the internal combustion engine may be a gasoline engine or a diesel engine.

DESCRIPTION OF SYMBOLS 10 Cooling water circuit 11 Engine 12 Radiator 13 Pump 17 Bypass flow path 18 Thermostat 19 Water temperature sensor 20, 40, 50 Refrigerant circuit (as working fluid circuit)
21, 41 Steam generator 22 Expander 23 Primary condenser 26 Secondary condenser 27 Refrigerant pump 28 Control device 33 Bypass flow path 34 Flow control valve 51 EGR cooler (as steam generator)
58, 59 Piping A Branch point B Junction point

Claims (5)

A steam generator for generating working fluid steam; an expander for expanding the working fluid steam; a condenser for condensing the working fluid flowing out from the expander; and a working fluid flowing out from the condenser In the Rankine cycle device comprising a pump for pumping to the steam generator, and a working fluid circuit for sequentially connecting the steam generator, the expander, the condenser and the pump,
The Rankine cycle device according to claim 1, wherein the condenser causes heat exchange between the cooling water downstream of the radiator for cooling the cooling water of the internal combustion engine and the working fluid. The condenser in the working fluid circuit is a primary condenser, and a secondary condenser is provided downstream of the primary condenser,
The Rankine cycle apparatus according to claim 1, wherein the working fluid flowing out from the primary condenser is condensed by the secondary condenser.   The Rankine cycle apparatus according to claim 1 or 2, wherein a heat source of the steam generator is cooling water upstream of the radiator.   The Rankine cycle apparatus according to claim 1 or 2, wherein the heat source of the steam generator is waste heat of EGR gas or waste heat of oil of an oil cooler.   The working fluid circuit includes a bypass flow path that connects an upstream side of the primary condenser and an upstream side of the secondary condenser, and a flow rate control valve that controls a flow rate flowing through the primary condenser and the bypass flow path. The Rankine-cycle apparatus of Claim 2 provided with.

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