JP7057129B2 - Vehicle waste heat recovery device - Google Patents

Description

The present invention expands a refrigerant pump that circulates the working fluid, a heater that heats the working fluid sent by the refrigerant pump by the waste heat of the vehicle engine, and a working fluid that is heated and vaporized by the heater. The present invention relates to a waste heat recovery device for a vehicle provided with a Rankine cycle having an expander for generating an output and a Rankine condenser for condensing the working fluid expanded by the expander.

As a prior art, there is known a waste heat regeneration system disclosed in Patent Document 1 that generates energy by utilizing waste heat of an engine. The waste heat regeneration system that uses the waste heat of this engine uses the waste heat of the refrigeration cycle for the Rankin cycle, so it has an internal combustion engine cooling system that cools the heat generated by the internal combustion engine with cooling water and a compressor that compresses the refrigerant. A heat exchanger that condenses and liquefies a high-temperature and high-pressure refrigerant compressed by the compressor, an expansion valve that vaporizes the refrigerant liquefied by the heat exchanger by expanding it, and air by the vaporized refrigerant. A refrigeration cycle system including a cooling evaporator, a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the medium of the Rankin cycle system, and an evaporator that vaporizes the medium by the heat of the cooling water. A Rankin cycle system including an expander that generates energy by the vaporized medium, a condenser that condenses and liquefies the vaporized medium, and a pump that sends the liquefied medium to the heat exchanger. It is a waste heat regeneration system equipped with.

Further, in Patent Document 2, as in Patent Document 1, it is a waste heat regeneration system that generates energy by using waste heat of an engine, and since the waste heat of the refrigeration cycle is used for the Rankin cycle, the refrigeration cycle is described. An air conditioner heat exchanger (first heat exchanger) that exchanges heat between the discharged refrigerant and the working fluid of the Rankin cycle, and the working fluid on the downstream side of the heat exchanger and the working fluid on the downstream heat side of the expander in the Rankin cycle. A waste heat regeneration system including an internal heat exchanger for heat exchange and a Rankin cycle provided with a boiler for heating the working fluid by utilizing the waste heat of the engine is disclosed.

Further, in Patent Document 3, as in Patent Document 1, it is a waste heat recovery system that generates energy by using engine waste heat, and since the waste heat of the refrigeration cycle is used, it is referred to as a discharge refrigerant in the refrigeration cycle. A heat exchanger that exchanges heat with the working fluid of the Rankin cycle, a Rankin cycle provided with a boiler that heats the working fluid using waste heat of the engine, and a refrigeration cycle provided with a capacitor on the downstream side of the heat exchanger. A waste heat recovery system equipped with the above is disclosed.

JP-A-2009-20204 JP 2011-85025 JP-A-2005-329843

Such a prior art response is a Rankin system that recovers energy by utilizing the waste heat of the engine and the waste heat of the refrigeration cycle, but the operation of these Rankin systems utilizes the waste heat of the engine, that is, Since the heat is recovered from the engine for operation, when the engine is started in a cold outside air such as in winter, it is difficult for the engine to warm up, so the Rankin system cannot be operated promptly. was there. Similarly, when the Rankin system is operated after the engine has been sufficiently warmed up in a cold outside air such as in winter, the Rankin system recovers the heat of the engine through the engine cooling water. When dehumidifying and heating the interior space of a vehicle, there is also a problem that the temperature of the engine cooling water used for heating does not rise sufficiently and the heating capacity becomes insufficient. Did not give sufficient consideration to engine warming and room heating during the winter months.

INDUSTRIAL APPLICABILITY The present invention solves the above-mentioned problems of the prior art, and can quickly warm up the engine even in a cold outside air such as in winter, and can provide a Rankin system after warming up the engine. Even if the engine is operated and the Rankin system recovers the heat of the engine cooling water, the lack of heating capacity can be compensated for when the vehicle interior space is dehumidified and heated by supplying the waste heat from the refrigeration cycle to the engine cooling water. It provides a vehicle waste heat recovery system that can be used.

In order to achieve the above object, the invention of claim 1 is an expansion that heats a working fluid by utilizing waste heat of an engine and an expansion that expands a working fluid via the heater to generate power. It has a Rankin cycle circuit in which a machine, a Rankin condenser for condensing the working fluid via the expander, and a working fluid pump for delivering the working fluid via the Rankin condenser to the heater are sequentially arranged. A Rankin cycle system, an engine cooling water system having an engine cooling water circuit in which cooling water circulates through a pump via the heater and the engine, a compressor for compressing the refrigerant, and compression by the compressor. The heat exchanger includes a heat exchanger that dissipates heat from the refrigerant , a decompression device that decompresses the refrigerant, and a refrigeration cycle system having a refrigeration cycle circuit in which an evaporator that heats the decompressed refrigerant is sequentially arranged. A heat exchanger that exchanges heat between the cooling water flowing through the engine cooling water circuit and the refrigerant flowing through the refrigeration cycle circuit, and is arranged between the heater and the engine in the engine cooling water circuit. It is a waste heat recovery system for vehicles.

The invention of claim 2 is the invention of claim 1, wherein the heat exchanger is a waste heat recovery system for a vehicle arranged on the downstream side of the heater in the engine cooling water circuit.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the refrigerating cycle system uses the heat exchanger and the depressurizing radiator to exchange heat with the outside air for the refrigerant compressed by the compressor. It is a waste heat recovery system for vehicles arranged between the device and the device.

Further, according to the invention of claim 4, in the invention of claim 3, the refrigerating cycle circuit includes a space between the compressor and the heat exchanger and a space between the heat exchanger and the decompression device. It is a waste heat recovery system for vehicles provided with a bypass path that is connected to bypass the heat exchanger and a switching device that switches the flow of the refrigerant to the heat exchanger side or the pipes path side.

The invention according to claim 5 is the invention according to claim 4, wherein the switching device is a waste heat recovery system for a vehicle, which is a switching valve provided at a connection portion of the bypass path.

Further, in the invention according to claim 6, in the invention according to any one of claims 4 or 5, the discharge refrigerant temperature on the discharge side of the compressor in the refrigeration cycle circuit is the heat exchanger in the engine cooling water circuit. When the temperature is higher than the cooling water temperature on the inlet side, the switching device causes the refrigerant to flow to the heat exchanger side, and the discharge refrigerant temperature on the discharge side of the compressor is the inlet of the heat exchanger in the engine cooling water circuit. The switching device is a waste heat recovery system for vehicles controlled so that the refrigerant flows to the bypass road side when the temperature of the cooling water on the side is equal to or lower than that of the cooling water.

According to the present invention, a compressor that compresses the refrigerant, a heat exchanger that dissipates heat from the refrigerant compressed by the compressor, and a decompression device that decompresses the refrigerant after heat exchange with the outside air by the radiator. A refrigerating cycle system having a refrigerating cycle circuit in which evaporators for heating depressurized refrigerants are sequentially arranged is provided, and the heat exchanger includes cooling water flowing through the engine cooling water circuit and refrigerant flowing through the refrigerating cycle circuit. It is a heat exchanger that exchanges heat, and since it is arranged between the heater and the engine in the engine cooling water circuit, the heat of the refrigerant compressed by the operation of the compressor in the refrigeration cycle system is applied to the engine. Since it can be supplied to the cooling water flowing through the cooling water circuit, the engine can be quickly warmed up in a cold outside air such as in winter. Further, even if the Rankin cycle system is operated after the engine is warmed up to recover the heat of the cooling water flowing through the engine cooling water circuit, the heat of the refrigerant compressed by the operation of the compressor in the refrigerating cycle system is used in the engine cooling water circuit. By supplying the flowing cooling water, there is an advantage that the lack of heating capacity can be compensated for when the vehicle interior space is dehumidified and heated.

Further, since the heat exchanger is arranged on the downstream side of the heater in the engine cooling water circuit, the temperature difference between the engine cooling water whose temperature has dropped by passing through the heater and the high temperature refrigerant is secured. Since the heat can be exchanged, there is an advantage that the heat exchange efficiency is improved.

Further, in the refrigeration cycle system, a radiator for heat exchange of the refrigerant compressed by the compressor with the outside air is arranged between the heat exchanger and the decompression device, so that the heat exchanger can dissipate heat completely. Since the heat of the non-refrigerant can be dissipated by the radiator, there is an advantage that the efficiency of the refrigerating circuit is improved.

The refrigeration cycle circuit includes a bypass path that connects between the compressor and the heat exchanger and between the heat exchanger and the decompression device to bypass the heat exchanger, and a flow of refrigerant. Since a switching device for switching to the heat exchanger side or the bypass path side is provided, for example, the discharge refrigerant temperature on the discharge side of the compressor in the refrigeration cycle circuit is the heat exchanger in the engine cooling water circuit. When the temperature is lower than the cooling water temperature on the inlet side of the above, heat exchange with the heat exchanger has the advantage that it is possible to prevent the warming of the engine from being hindered and the efficiency of the refrigeration circuit system from being reduced. ..

Further, since the switching device is a switching valve provided at the connection portion of the bypass path, there is an advantage that it is easy to connect the switching valve to the refrigeration cycle circuit.

Further, when the discharge refrigerant temperature on the discharge side of the compressor in the refrigeration cycle circuit is higher than the cooling water temperature on the inlet side of the heat exchanger in the engine cooling water circuit, the switching device is on the heat exchanger side. When the discharge refrigerant temperature on the discharge side of the compressor is equal to or lower than the cooling water temperature on the inlet side of the heat exchanger in the engine cooling water circuit, the switching device causes the refrigerant to flow to the bypass path side. Therefore, for example, when the discharge refrigerant temperature on the discharge side of the compressor in the refrigeration cycle circuit is equal to or lower than the cooling water temperature on the inlet side of the heat exchanger in the engine cooling water circuit, the heat exchanger By exchanging heat with the heat exchange, there is an advantage that it is possible to surely suppress that the warming of the engine is hindered and the efficiency of the refrigerating circuit is lowered.

Configuration diagram of the waste heat recovery system for vehicles, which is the first embodiment. Configuration diagram of the waste heat recovery system for vehicles, which is the second embodiment. A block diagram showing the flow of the refrigerant (heat exchanger side) in the waste heat recovery system for vehicles which is the second embodiment. A block diagram showing the flow of the refrigerant (bypass road side) in the waste heat recovery system for vehicles which is the second embodiment. Flow chart of control of waste heat recovery system for vehicle which is 1st Example and 2nd Example Flow chart of the switching valve of the second embodiment

Next, a first embodiment of the present invention will be described with reference to FIGS. 1 and 5.
FIG. 1 is a diagram showing a configuration of a vehicle waste heat recovery system 1 according to an embodiment of the present invention. The waste heat recovery system of the present invention is a vehicle waste heat recovery system 1 that recovers waste heat from a vehicle engine. Is. The vehicle waste heat recovery system 1 includes a Rankine cycle system 2, an engine cooling water system 3, and a refrigeration cycle system 4, and the vehicle waste heat recovery system 1 has a control device 5. The control device 5 controls each system of the Rankine cycle system 2 and the refrigeration cycle system 4.

The Rankine cycle system 2 is a system that recovers the waste heat of the engine and converts it into electric power or a rotational driving force that assists the engine, and heats the circulating working fluid via the cooling water of the engine 23 described later. The heater 11, the expander 12 that expands the working fluid that has passed through the heater 11 to generate power, the Rankine condenser 13 that condenses the working fluid that has passed through the expander 12, and the Rankine condenser 13. It is provided with a Rankine cycle circuit 10 in which working fluid pumps 14 that sequentially send the working fluid that has passed through to the heater 11 are arranged.

The engine cooling water system 3 is a system for cooling the engine 23, which is an internal combustion engine mounted on the vehicle, and sequentially passes the engine 23, the pump 24, the thermostat 25, and the radiator 26 through which the cooling water for cooling the engine 23 passes. It has an engine cooling water circuit 20 having an arranged circulation path 21 and a branch passage 22 arranged in the middle of the circulation path 21, and the branch passage 22 is between the pump 24 and the radiator 26 and is a thermostat 25. Branches from the circulation path 21 at the branch point 29 in which the radiator 26 is arranged, and joins the circulation path 21 again at the branch point 29 between the radiator 26 and the engine 3.

The pump 24 pumps the cooling water that has passed through the engine 23, and the thermostat 25 adjusts the amount of the cooling water that flows into either the radiator side or the branch passage side depending on the temperature of the cooling water. The cooling water that has passed through the thermostat 25 and has flowed into the radiator side is cooled by exchanging heat with the running wind of the vehicle and the air blown by a fan (not shown) by passing through the radiator 26, and then sent to the thermostat. The cooling water that has passed through 25 and has flowed into the branch passage side is sent to the engine via the branch point 29 without passing through the radiator 26. For example, when the temperature of the cooling water is lower than the predetermined first set temperature (for example, 90 ° C.), the thermostat 25 causes the cooling water to flow to the branch passage side without flowing to the radiator side, and the cooling water temperature is the predetermined first setting. If the temperature is higher than the set temperature, the cooling water is flowed to the radiator side without flowing to the branch passage side, and the amount of cooling water to be flowed to the radiator side and the amount of cooling water to be flowed to the branch passage side are adjusted according to the temperature of the cooling water. Although the pump 24 is driven by the engine 23, it may be driven by another driving means such as an electric motor.

Therefore, when the engine 23 is not sufficiently warmed at the beginning of the engine start, the cooling water passing through the engine 23 is not hot, so that the cooling water flows through the branch passage 22 without flowing to the radiator side and returns to the engine 23. It flows in. On the other hand, when the vehicle is climbing a slope and the engine 23 rotates at a high speed, or when a sufficient time has passed since the engine 23 started in summer, the engine 23 becomes a high temperature state. Therefore, since the cooling water is also at a high temperature, the cooling water flows to the radiator side, is cooled by the radiator 26, and then flows into the engine 23 again to cool the engine 23.

Further, the engine cooling water circuit system 3 has a heater core 28 for heat exchange for warming the vehicle interior space. The heater core 28 is a heat exchanger that heats the vehicle interior space by exchanging heat between the cooling water warmed by the waste heat of the engine 23 and the air in the space where the heater core 28 is installed, and the heater core 28 is the engine cooling water. It is arranged on the circulation path 21 of the system 3 between the engine 23 and the branch passage 22. In this embodiment, the heater core 28 is arranged on the circulation path 21 of the engine cooling water system 3, but the heater core may be arranged on the passage branching from the circulation path 21 and rejoining the circulation path 21. I do not care. In that case, a switching valve is provided at the branch point branching from the circulation path 21 to control the cooling water to flow to the heater core side or to flow to the circulation path side without flowing to the heater core side.

The heater 11 disposed in the Rankine cycle circuit 10 is a heater 11 also disposed in the branch passage 22 of the engine cooling water circuit 20, and is the working fluid circulating in the Rankine cycle circuit 10 and the engine cooling water. It is a heater 11 that exchanges heat with the cooling water circulating in the circuit 20. By the heater 11, the Rankine cycle system 2 recovers the waste heat of the engine through the cooling water circulating in the engine cooling water circuit 20 and converts it into electric power or a rotational driving force that assists the engine 23. Further, the working fluid pump 14 provided in the Rankine cycle circuit 10 is driven when the temperature of the cooling water immediately before passing through the heater 11 becomes a predetermined second set temperature (for example, 85 ° C.) or higher, and the heater 11 is driven. It is controlled to stop when the temperature of the cooling water immediately before passing through is lower than the predetermined second set temperature.

The refrigeration cycle system 4 is used in an air conditioning system mounted on a vehicle, and is a compressor 31 that is driven by an engine 23 or an electric motor to compress a refrigerant, and an outside air that compresses the refrigerant by the compressor 31. A radiator 32 as a condenser that condenses heat by exchanging heat with the radiator 32, an expansion valve 33 as a decompression device that decompresses the refrigerant after heat exchange with the outside air and condensing with the radiator 32, and cooling the air in the vehicle interior. A refrigeration cycle circuit 30 is provided in which an evaporator 34 for heat exchange between the refrigerant decompressed by the expansion valve 33 and the air in the vehicle interior is sequentially arranged. In this embodiment, the radiator 32 as a condenser is used. However, for example, when the refrigerant is carbon dioxide, the carbon dioxide refrigerant does not condense, so the carbon dioxide refrigerant is used instead of the radiator 32 as the condenser. It may be a radiator that dissipates heat.

The operation of the refrigeration cycle system 4 is performed by turning on a switch of an air conditioning system (not shown) by the vehicle user, and in the case of the compressor 31 operated by driving the engine 23, for example, the engine 23 and the compressor An electromagnetic clutch (not shown) arranged between 31 transmits the drive of the engine 23 to the compressor 31 by turning on the switch of the air conditioning system, and the compressor 31 is driven. When the compressor 31 is operated by an electric motor, the electric motor is operated by turning on the switch of the air conditioning system to drive the compressor 31.

Further, the vehicle waste heat recovery system 1 has a heat exchanger 27 that exchanges heat between the refrigerant flowing through the refrigeration cycle circuit 30 and the cooling water flowing through the engine cooling water circuit 20. The heat exchanger 27 is arranged between the compressor 31 of the refrigerating cycle circuit 30 and the radiator 32, and is arranged on the downstream side of the heater in the branch passage 22 of the engine cooling water circuit 20. The heat of the refrigerant discharged from the 31 and heated to a high temperature is transferred to the cooling water via the heat exchanger 27.

In the refrigeration cycle system 4 of the present embodiment, the heat exchanger 27 that exchanges heat between the refrigerant flowing through the refrigeration cycle circuit 30 and the cooling water flowing through the engine cooling water circuit 20 and the refrigerant compressed by the compressor 31 are used. A radiator 32 as a condenser that condenses heat by exchanging heat with the outside air is arranged in the refrigeration cycle circuit 30, but if the heat exchanger 27 is arranged, the radiator 32 is not necessarily arranged. It does not have to be.

Next, the operation of this embodiment will be described. When the engine is started, the pump 24 is driven and the cooling water circulates in the engine cooling water circuit 20. Since the temperature of the cooling water is low at the beginning of the engine start and the temperature of the cooling water passing immediately before the thermostat 25 is less than the first set temperature (90 ° C.), the cooling water flows into the branch passage side instead of the radiator side by the thermostat 25. Then, after passing through the heater 11 and the heat exchanger 27, it flows into the engine 23 again and circulates in the engine cooling water circuit 20. When the outside air is cold, such as when the engine is started in winter, the temperature of the cooling water is lower than in summer. It will take. Further, since the cooling water having a low temperature also flows through the heater core 28 for warming the vehicle interior space, the vehicle interior space cannot be heated.

Therefore, since it takes time to warm up the engine 23, the air conditioning system is switched on when the driver determines that he / she wants to promote warming up. When the switch of the air conditioning system is turned on, the compressor 31 is driven, the high temperature refrigerant discharged from the compressor 31 flows into the heat exchanger 27, and the high temperature refrigerant exchanges heat with the cooling water whose temperature is still low to cool. The temperature of the water is raised, and the cooling water whose temperature has been raised by the heat exchanger 27 flows into the engine 23 again, and the warm air of the engine 23 is promoted. Further, the cooling water whose temperature has risen by the heat exchanger 27 also flows into the heater core 28 to promote heating of the vehicle interior space.

When the warming of the engine 23 is promoted and the temperature of the cooling water rises, and the temperature of the cooling water immediately before passing through the heater 11 reaches the second set temperature (85 ° C.), the working fluid pump 14 is driven and operates. The fluid circulates in the Rankine cycle circuit 10, the Rankine cycle system 2 operates, and the expander 21 drives to generate power. Here, when the Rankine cycle system 2 is operated, the heat of the cooling water is transferred to the working fluid in the heater 11, so that the temperature of the cooling water after passing through the heater is lowered. However, in this embodiment, since the heat exchanger 27 is arranged on the downstream side of the heater in the branch passage 22 of the engine cooling water circuit 20, the cooling water whose temperature has dropped after passing through the heater is the heat exchanger 27. Since the heat is recovered from the high-temperature discharged refrigerant, it is possible to promote the warming of the engine and the heating of the vehicle interior space in winter even when the Rankin cycle system 2 is operating.

If the power recovered by the expander 12 (Rankin output) is insufficient, for example, if the power recovered by the expander 12 is converted into electric power, the power does not reach a predetermined value, or the expansion is performed. If the pressure difference between the upstream side and the downstream side of the machine 12 does not reach a predetermined value, the control device 5 considers that the Rankin output is insufficient and stops driving the working fluid pump 14.

A second embodiment of the present invention will be described with reference to FIGS. 2 to 5 and 6. The difference between the first embodiment and the second embodiment is that in the second embodiment, a bypass path 35 that bypasses the heat exchanger 27 is provided between the compressor 31 and the radiator 32 of the refrigeration cycle circuit 30. In the first embodiment, there is no bypass path 35, and other configurations are the same as those in the first embodiment. Since the same reference numerals as those of the first embodiment in the second embodiment are the same components, detailed description thereof will be omitted.

In FIG. 2, the refrigeration cycle system 4 includes a space between the compressor 31 and the heat exchanger 27 of the refrigeration cycle circuit 30 common to the refrigeration cycle circuit 4 of the first embodiment, and a heat exchanger 27 and a radiator 32. It has a bypass path 35 that is connected to the space and bypasses the heat exchanger 27, and a switching valve 36 as a switching device that switches the flow of the refrigerant discharged from the compressor 31 to the heat exchanger side or the bypass path side. The switching valve 36 is arranged at the compressor side connection portion (the connection portion between the compressor and the heat exchanger) of the bypass path 35. In this embodiment, the switching valve 36 is arranged at the compressor side connection portion of the bypass path 35, but the switching valve 36 is the radiator side connection portion of the bypass path 35 (between the heat exchanger and the radiator). It may be arranged at the connection portion with the passage). Further, in the present embodiment, the switching device is the switching valve 36, but the switching device is provided with on-off valves, for example, on the bypass path and on the refrigeration cycle circuit in which the heat exchanger 27 to be bypassed is arranged. The flow of the refrigerant discharged from the compressor 31 may be switched to the heat exchanger side or the bypass road side.

Further, in the refrigeration cycle system 4 of the present embodiment, the heat exchanger 27 for heat exchange between the refrigerant flowing through the refrigeration cycle circuit 30 and the cooling water flowing through the engine cooling water circuit 20 is compressed by the compressor 31. A radiator 32 as a condenser that condenses the refrigerant by exchanging heat with the outside air is arranged in the refrigeration cycle circuit 30, but if the heat exchanger 27 is arranged, the radiator 32 is not necessarily arranged. It does not have to be installed.

Further, in the refrigeration cycle system 4 of the present embodiment, the bypass path 35 is connected between the compressor 31 and the heat exchanger 27 and between the heat exchanger 27 and the radiator 32 to generate heat. The exchanger 27 is bypassed, but the bypass path 35 is connected between the compressor 31 and the heat exchanger 27 and between the expansion valve 33 and the radiator 32, and the heat exchanger 27 and the radiator 32 are connected. It may be a heat exchanger that bypasses and. That is, it may be a bypass path that bypasses the heat exchanger 27.

Further, in the refrigeration cycle system 4 of the present embodiment, even when the radiator 32 is not arranged, the compressor 31 and the heat exchanger 27 are similarly provided as long as the bypass path bypasses the heat exchanger 27. A bypass path connecting the space and the space between the expansion valve 33 and the heat exchanger 27 may be used.

The operation of the switching valve 36 is performed by the control device 5 as follows. A temperature sensor (not shown) provided between the compressor 31 of the refrigeration cycle circuit 30 and the switching valve 36 is provided between the temperature T1 of the discharged refrigerant and between the heater 11 and the heat exchanger 27 of the engine cooling water circuit 20. The temperature T2 of the cooling water after passing through the heater is measured by a temperature sensor (not shown), and when the temperature T1 of the discharged refrigerant exceeds the temperature T2 of the cooling water, the control device 5 sets the switching valve 36 to the heat exchanger side. The refrigerant is switched and flows to the heat exchanger 27, and when the temperature T1 of the discharged refrigerant is equal to or lower than the temperature T2 of the cooling water, the control device 5 switches the switching valve 36 to the bypass path side and flows the refrigerant to the bypass path 35.

Next, the operation of this embodiment will be described. When the engine is started, the pump 24 is driven and the cooling water circulates in the engine cooling water circuit 20. Since the temperature of the cooling water is low at the beginning of the engine start and is less than the first set temperature (90 ° C) of the cooling water passing immediately before the thermostat 25, the cooling water flows into the branch passage side instead of the radiator side by the thermostat 25. After passing through the heater 11 and the heat exchanger 27, it flows into the engine 23 again and circulates in the engine cooling water circuit 20. When the outside air is cold, such as when the engine is started in winter, the temperature of the cooling water is lower than in summer. It will take. Further, since the cooling water having a low temperature also flows through the heater core 28 for warming the vehicle interior space, the vehicle interior space cannot be heated.

Therefore, since it takes time to warm up the engine 23, the air conditioning system is switched on when the driver determines that he / she wants to promote warming up. When the switch of the air conditioning system is turned on, the compressor 31 is driven, and the high temperature refrigerant discharged from the compressor 31 circulates in the refrigeration cycle circuit 30. Since the cooling water temperature T2 after passing through the heater is lower than the temperature T1 of the discharged refrigerant because it is at the time of starting the engine, the temperature T1 of the discharged refrigerant exceeds the cooling water temperature T2 after passing through the heater. The switching valve 36 switches the discharged refrigerant so as to flow to the heat exchanger side, and the high-temperature discharged refrigerant exchanges heat with the cooling water whose temperature is still low to raise the temperature of the cooling water, and the temperature is raised by the heat exchanger 27. The cooling water flows into the engine 23 again, and the warm air of the engine 23 is promoted. Further, the cooling water whose temperature has risen by the heat exchanger 27 also flows into the heater core 28 to promote heating of the vehicle interior space.

Since the temperature of the indoor space is lower in winter than in summer, the refrigerating cycle system 4 operates with a low load. Therefore, the temperature of the cooling water rises due to the heat exchanger 27 to warm the engine 23 and the interior space of the vehicle. When heating is promoted, the cooling water temperature T2 after passing through the heater rises, the temperature T1 of the discharged refrigerant becomes the cooling water temperature T2 or less, and the switching valve 36 switches so that the discharged refrigerant flows to the bypass passage side. .. Since the discharged refrigerant flows to the bypass passage side and does not flow to the heat exchanger 27, it is possible to prevent the temperature of the discharged refrigerant from rising due to the heat exchanger 27, thereby suppressing the decrease in the efficiency of the refrigeration cycle system 4. There is an effect that can be done.

In the first and second embodiments of the present invention, since the heat exchanger 27 in the engine cooling water circuit 20 is arranged on the downstream side of the heater 11, the heat exchanger 27 in the engine cooling water circuit 20 and the heat exchanger 27 Compared to the case where the heater 11 is arranged in the opposite direction, the temperature difference between the cooling water that has passed through the heater 11 and the temperature has dropped and the high-temperature discharged refrigerant can be secured, so that the heat exchange in the heat exchanger 27 can be secured. It has the effect of improving efficiency.

1 Waste heat recovery system for vehicles 2 Rankine cycle system 3 Engine cooling water system 4 Refrigeration cycle system 5 Control device 10 Rankine cycle circuit 11 Heater 12 Inflator 13 Rankine condenser 14 Working fluid pump 20 Engine cooling water circuit 21 Circulation path 22 Branch passage 23 Engine 24 Pump 25 Thermostat 26 Radiator 27 Heat exchanger 28 Heater core 29 Branch point 30 Refrigeration cycle circuit 31 Compressor 32 Dissipator 33 Expansion valve 34 Evaporator 35 Bypass path 36 Switching valve

Claims (6)

For a heater that heats the working fluid using the waste heat of the engine, an expander that expands the working fluid that has passed through the heater to generate power, and a Rankine that condenses the working fluid that has passed through the expander. A Rankine cycle system having a Rankine cycle circuit in which a condenser and a working fluid pump for sequentially delivering a working fluid via the Rankine condenser to the heater are arranged.
An engine cooling water system having an engine cooling water circuit in which cooling water circulates through a pump via the heater and the engine, and an engine cooling water system.
A refrigeration cycle circuit in which a compressor that compresses the refrigerant, a heat exchanger that dissipates heat from the refrigerant compressed by the compressor, a decompression device that decompresses the refrigerant , and an evaporator that heats the decompressed refrigerant are sequentially arranged. Equipped with a refrigeration cycle system
The heat exchanger is a heat exchanger that exchanges heat between the cooling water flowing through the engine cooling water circuit and the refrigerant flowing through the refrigerating cycle circuit, and the heater and the engine in the engine cooling water circuit. A waste heat recovery system for vehicles, which is characterized by being arranged between them. The waste heat recovery system for a vehicle according to claim 1, wherein the heat exchanger is arranged on the downstream side of the heater in the engine cooling water circuit. The refrigerating cycle system according to claim 1 or 2, wherein a radiator for exchanging heat of the refrigerant compressed by the compressor with the outside air is provided between the heat exchanger and the decompression device. Waste heat recovery system for vehicles The refrigeration cycle circuit includes a bypass path that connects between the compressor and the heat exchanger and between the heat exchanger and the decompression device to bypass the heat exchanger, and a flow of refrigerant. The waste heat recovery system for a vehicle according to claim 3, wherein a switching device for switching to the heat exchanger side or the bypass road side is provided. The vehicle waste heat recovery system according to claim 4, wherein the switching device is a switching valve provided at a connection portion of the bypass path. When the discharge refrigerant temperature on the discharge side of the compressor in the refrigeration cycle circuit is higher than the cooling water temperature on the inlet side of the heat exchanger in the engine cooling water circuit, the switching device moves the refrigerant to the heat exchanger side. Shed,
When the discharge refrigerant temperature on the discharge side of the compressor is equal to or lower than the cooling water temperature on the inlet side of the heat exchanger in the engine cooling water circuit, the switching device is controlled to flow the refrigerant to the bypass path side. The vehicle waste heat recovery system according to any one of claims 4 or 5.

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