JP5516433B2 - Rankine cycle system equipment - Google Patents

Description

  The present invention relates to a Rankine cycle system device that recovers waste heat generated from an internal combustion engine through steam.

  2. Description of the Related Art A waste heat recovery apparatus that recovers waste heat generated by driving an internal combustion engine using a Rankine cycle is known. In this type of waste heat recovery device, for example, a water-cooled cooling system of an internal combustion engine has a sealed structure, and an expander (turbine) is driven using refrigerant (steam) vaporized by waste heat in the internal combustion engine. Some have recovered the thermal energy they have converted into mechanical power or electrical energy. For example, Patent Document 1 discloses such a technique.

  In addition, in a hybrid vehicle (hereinafter simply referred to as “hybrid vehicle”) that is used as a drive power source by switching or using both an internal combustion engine and an electric motor, waste heat is recovered from the electric motor and a device for obtaining power from the electric motor. Patent Documents 2 and 3 disclose such systems. The heat management system of Patent Document 2 exchanges heat between a first refrigerant that circulates in the engine and a second refrigerant that exchanges heat with the H / V motor. The heat storage system of Patent Document 3 preferentially collects one of waste heat stored by the refrigerant of the system that cools the internal combustion engine and waste heat stored by the refrigerant of the system that cools the electric diameter parts of the vehicle into the heat storage tank. .

JP 2010-133299 A JP 2009-202794 A JP 2004-132189 A

  By the way, an apparatus for recovering waste heat using the Rankine cycle is suitable for cooling the internal combustion engine by condensing the vaporized refrigerant because the waste heat is recovered and the vaporized refrigerant is supplied again to the engine. It is necessary to cool down to a certain temperature. A condenser (condenser) is used for cooling the refrigerant, and the refrigerant is cooled by exchanging heat between the air forcedly supplied by the cooling fan and the refrigerant. However, the vaporized refrigerant has a high temperature, and in order to condense the refrigerant and cool it to a predetermined temperature, the amount of heat exchange increases. Therefore, the condenser and the cooling fan must be made large. For this reason, the space for mounting the condenser is limited, and the waste heat recovery apparatus itself is increased in size. Large cooling fans also consume a lot of power, and there is room for improvement in terms of improving fuel consumption.

  Accordingly, an object of the present invention is to improve the ability to cool the refrigerant that obtains waste heat from the internal combustion engine and vaporizes it, and to reduce the size of the condenser.

  A Rankine cycle system device of the present invention that solves such a problem includes a hybrid system including an internal combustion engine and another power engine, and a first refrigerant that circulates in the internal combustion engine and is vaporized by waste heat of the internal combustion engine. A waste heat recovery machine that recovers energy of waste heat from the vaporized first refrigerant, a condenser that cools the vaporized first refrigerant, and a second refrigerant that exchanges heat with the other power engine A heat exchanging unit that exchanges heat between the first refrigerant and the second refrigerant in the condenser; a temperature measuring unit that measures a temperature of the second refrigerant; and a temperature measuring unit that measures the temperature of the second refrigerant. And a control unit that introduces the second refrigerant into the heat exchange unit based on temperature.

  With this configuration, since the second refrigerant is supplied to the condenser, the vaporized first refrigerant can exchange heat with the atmosphere and also exchange heat with the second refrigerant in the condenser. For this reason, the ability to cool the first refrigerant in the condenser is improved. That is, in the condenser, the amount of heat exchange with the atmosphere of the first refrigerant can be reduced by the amount of heat exchange between the first refrigerant and the second refrigerant, so that the condenser can be downsized.

  Moreover, in the structure of this invention, since a 2nd refrigerant | coolant acquires waste heat from a 1st refrigerant | coolant and heats up, the other power engine which heat-exchanges with a 2nd refrigerant | coolant can be warmed up. When the other power engine receives heat and warms up early, the operating efficiency of the other power engine can be improved. Such other power engines can employ an electric motor and peripheral devices incorporated together with the electric motor, for example, an inverter or a storage battery.

  In the Rankine cycle system apparatus, the control unit may be configured to introduce the second refrigerant into the heat exchange unit when the temperature of the second refrigerant is lower than a first predetermined temperature.

  When the temperature of the second refrigerant is low, the amount of heat that the second refrigerant takes away from the first refrigerant is large, and the cooling capacity is high. Furthermore, since the temperature of the low-temperature second refrigerant is increased by the heat obtained from the first refrigerant, the other power engine can be warmed up. Here, the first predetermined temperature is a temperature at which the other power engine is warmed up.

  In the Rankine cycle system device, the control unit is configured to introduce the second refrigerant into the heat exchange unit when the temperature of the first refrigerant at the outlet of the condenser is equal to or higher than a second predetermined temperature. be able to.

  The first refrigerant is used not only to obtain heat from the internal combustion engine but also to appropriately cool the internal combustion engine. For this reason, it is necessary to cool the first refrigerant. The second refrigerant is supplied to the condenser, and the amount of heat taken away from the first refrigerant is increased. Thereby, a 1st refrigerant | coolant is cooled and an internal combustion engine can be cooled to appropriate temperature. Here, the second predetermined temperature is an upper limit temperature suitable for supplying to the internal combustion engine.

  The present invention includes a hybrid system including an internal combustion engine and another power engine, and the first refrigerant circulating in the internal combustion engine exchanges heat with the second refrigerant that exchanges heat with the other power engine. The ability to cool the first refrigerant is improved, and the condenser can be reduced in size.

It is explanatory drawing which showed schematic structure of the Rankine cycle system apparatus which concerns on embodiment. It is a block diagram of a control system of a Rankine cycle system device. It is a flowchart of the control regarding the heat exchange of a refrigerant | coolant in operation | movement of a Rankine cycle system.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a schematic configuration of a Rankine cycle system apparatus 1 according to the present embodiment. The Rankine cycle system apparatus 1 includes a hybrid system 2. The hybrid system 2 includes an internal combustion engine 3 and an electric motor 4, and functions as a power source by driving either the internal combustion engine 3 or the electric motor 4 alone or both at the same time. The electric motor 4 constitutes another power engine together with the inverter 41 and the HV (hybrid) battery 42. The Rankine cycle system device 1 can be mounted on a vehicle.

  A first refrigerant passage 5 through which the first refrigerant circulates is provided in the internal combustion engine 3. The first refrigerant circulates in the internal combustion engine 3, cools the internal combustion engine 3, and is vaporized by waste heat generated from the internal combustion engine 3. The arrows shown in the figure indicate the direction in which the first refrigerant flows. The Rankine cycle system device 1 includes a waste heat recovery machine 6. The waste heat recovery machine 6 recovers waste heat energy from the first refrigerant vaporized by the waste heat of the internal combustion engine 3.

  In the Rankine cycle system apparatus 1, a second refrigerant passage 7 through which the second refrigerant circulates is provided. The second refrigerant exchanges heat with the electric motor 4, the inverter 41, and the HV battery 42. That is, the second refrigerant supplies heat to the electric motor 4, the inverter 41, and the HV battery 42, collects heat from the electric motor 4, the inverter 41, and the HV battery 42 to cool the electric motor 4, the inverter 41, and the HV battery 42. Or The second refrigerant may be configured to exchange heat with any one of the electric motor 4, the inverter 41, and the HV battery 42. In addition to the electric motor 4, the inverter 41, and the HV battery 42, the second refrigerant may be combined with the electric motor 4 in the hybrid system 2. It is good also as a structure which heat-exchanges with the peripheral device incorporated.

  The internal combustion engine 3 includes a cylinder block 30a and a cylinder head 30b of the internal combustion engine body 30. The first refrigerant passage 5 connects a block-side water jacket 31a formed in the cylinder block 30a and a head-side water jacket 31b formed in the cylinder head 30b. The first refrigerant in the first refrigerant passage 5 flows from the head side water jacket 31b side to the block side water jacket 31a. A gas-liquid separator 32, an evaporator 33, a superheater 34, a waste heat recovery machine 6, a condenser 35, a condensation tank 36, a vane type water pump 37, and a check valve 38 are sequentially provided in the first refrigerant passage 5 from the upstream side. A water pump 39 is arranged.

  The first refrigerant in the block-side water jacket 31a and the head-side water jacket 31b cools the cylinder block 30a and the cylinder head 30b. When the water pump 39 is activated, the first refrigerant in the block-side water jacket 31a and the head-side water jacket 31b is sent to the gas-liquid separator 32. The gas-liquid separator 32 separates the first refrigerant into vapor and liquid. The gas-liquid separator 32 is connected to the evaporator 33 by two passages 51 and 52. The gas separated in the gas-liquid separator 32 passes through the passage 51, and the liquid separated in the gas-liquid separator 32 passes through the passage 52. An electromagnetic valve 521 is provided in the passage 52. When the solenoid valve 521 is opened, the first refrigerant flows through the passage 52. Thereby, when the 1st refrigerant | coolant in the evaporator 33 runs short, it is comprised so that it can supply from the gas-liquid separator 32. FIG.

  The evaporator 33 is in communication with the superheater 34. The evaporator 33 and the superheater 34 are configured to exchange heat between the exhaust gas discharged from the internal combustion engine 3 and the first refrigerant. More specifically, the exhaust pipe 8 is formed so as to pass through the evaporator 33 and the superheater 34. The first refrigerant in the evaporator 33 is vaporized by obtaining heat from the exhaust gas. The vaporized first gas is sent to the superheater 34. The vaporized first refrigerant in the superheater 34 obtains heat from the exhaust gas and becomes high-temperature and high-pressure vapor. The superheater 34 is arranged upstream of the evaporator 33 in the exhaust pipe 8. Accordingly, the first refrigerant in the superheater 34 exchanges heat with the exhaust gas having a higher temperature than the first refrigerant in the evaporator 33.

  The high-temperature and high-pressure steam in the superheater 34 is then sent to the waste heat recovery machine 6. The waste heat recovery machine 6 is a waste heat recovery unit including a supersonic nozzle 61, a turbine 62, a generator 63, and a storage battery 64. High-temperature and high-pressure steam is sprayed from the supersonic nozzle 61 to the turbine 62. Thereby, the turbine 62 rotates. When the turbine 62 rotates, power is generated by the generator 63 and the generated electricity is stored in the storage battery 64. Thus, the waste heat recovery machine 6 recovers energy from the first refrigerant vaporized by the waste heat of the internal combustion engine 3.

  The condenser 35 condenses the steam after driving the turbine 62 in the waste heat recovery machine 6 into a liquid. The condenser 35 cools the first refrigerant by sending the first refrigerant to the subdivided passage and promoting heat exchange with the atmosphere. Further, a cooling fan 9 for forcibly supplying the atmosphere to the condenser 35 is provided. In addition, a first temperature sensor 10 that measures the temperature of the first refrigerant after condensation is provided at the outlet of the first refrigerant of the condenser 35.

  The first refrigerant condensed into the liquid by the condenser 35 is temporarily stored in the header tank 11 downstream of the condenser 35 and then sent to the condensation tank 36. The first refrigerant in the condensing tank 36 is supplied to the water pump 39 side by the vane type water pump 37. Further, the first refrigerant is supplied to the block-side water jacket 31 a by the water pump 39 and circulates in the internal combustion engine 3. Further, the vane type water pump 37 operates to adjust the amount of the first refrigerant in the gas-liquid separator 32. The check valve 38 between the vane type water pump 37 and the water pump 39 prevents the first refrigerant from flowing back to the vane type water pump 37.

  As described above, the first refrigerant recovers waste heat from the exhaust gas of the internal combustion engine body 30 and the internal combustion engine 3 and becomes high-temperature and high-pressure steam. The waste heat recovery machine 6 converts the heat energy of the vaporized first refrigerant into electric energy and recovers it. The vaporized first refrigerant is condensed again in the liquid state in the condenser 35. The condensed first refrigerant is sent to the internal combustion engine 3. Accordingly, the first refrigerant circulates in the Rankine cycle system device 1. Therefore, a Rankine cycle using the first refrigerant as a working fluid is configured.

  A heat exchange pipe 71 is formed in a part of the second refrigerant passage 7. The heat exchange pipe 71 is configured to pass through the condenser 35. The second refrigerant passing through the heat exchange pipe 71 exchanges heat with the first refrigerant in the condenser 35. The heat exchange pipe 71 functions as a heat exchange unit in the condenser 35 where the first refrigerant and the second refrigerant exchange heat. An electric pump 72 is provided in the second refrigerant passage 7. A second temperature sensor 73 in the second refrigerant passage 7 is provided. The second temperature sensor 73 can be arranged on the downstream side of the electric motor 4, the inverter 41, and the HV battery 42. The hybrid system 2 is provided with a cooling system (not shown) for separately cooling the electric motor 4, the inverter 41, and the HV battery 42.

  Next, the configuration of the control system 20 of the Rankine cycle system apparatus 1 will be described. FIG. 2 is a block diagram of the control system 20. The control system 20 has an ECU (Electronic Control Unit) 21. The ECU 21 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a known type digital computer in which input / output ports are connected by a bidirectional bus. The hybrid system 2 and the internal combustion engine 3 is controlled by exchanging signals with various sensors and actuators provided for the control of No. 3.

  In particular, in the present embodiment, the ECU 21 is electrically connected to the first temperature sensor 10 and the second temperature sensor 73. The ECU 21 acquires the temperature of the first refrigerant at the outlet of the condenser 35 measured by the first temperature sensor 10 and the temperature of the second refrigerant in the second refrigerant passage 7 measured by the second temperature sensor 73. The ECU 21 is electrically connected to the electric pump 72, the cooling fan 9, and the electromagnetic valve 521, and based on information acquired by various sensors of the hybrid system 2 and the internal combustion engine 3, the electric pump 72, the cooling fan 9 is controlled, and the open / close state of the solenoid valve 521 is controlled. In particular, the ECU 21 performs control for sending a drive signal to the electric pump 72 and introducing the second refrigerant into the heat exchange pipe 71 based on the temperature of the second refrigerant measured by the second temperature sensor 73.

  Next, control relating to heat exchange of the refrigerant during operation of the Rankine cycle system will be described with reference to FIG. FIG. 3 is a flowchart of control related to heat exchange of the refrigerant during operation of the Rankine cycle system. This control is performed by the ECU 21. Note that the second refrigerant is at a lower temperature than the first refrigerant under the conditions in which this control is performed.

In step S1, the ECU 21 determines whether or not the Rankine cycle system is in operation. If the ECU 21 determines YES in step S1, that is, if the Rankine cycle system is operating, the process proceeds to step S2. ECU21 in step S2, detects the temperature _{T 2} of the temperature _{T 1} and the second refrigerant of the first refrigerant. The temperature T ₁ of the first refrigerant is the temperature of the first refrigerant at the outlet of the condenser 35 measured by the first temperature sensor 10. The temperature T ₂ of the second refrigerant is the temperature of the second refrigerant in the second refrigerant passage 7 measured by the second temperature sensor 73.

ECU21 then in step S3, the temperature _{T 2} of the second refrigerant determined whether below the temperature _{T A.} The temperature T _A is the first predetermined temperature. Temperature _{T A} is the motor 4, is the temperature at which the warm-up has been completed of the inverter 41, HV battery 42. Therefore, it can be said that the process of step S3 is a process of determining whether the electric motor 4, the inverter 41, and the HV battery 42 have been warmed up and whether the inverter 41 and the HV battery 42 can be charged / discharged. ECU21 If judged YES in step S3, i.e., when the temperature _{T 2} of the second refrigerant is below the temperature _{T A,} the process proceeds to step S4.

  The ECU 21 introduces the second refrigerant into the condenser 35 in step S4. Specifically, the electric pump 72 is driven to cause the second refrigerant in the second refrigerant passage 7 to flow. Thereby, since a 2nd refrigerant | coolant passes the heat exchange pipe | tube 71, a 2nd refrigerant | coolant and a 1st refrigerant | coolant heat-exchange. The second refrigerant receives heat from the first refrigerant and raises the temperature. Since the second refrigerant whose temperature has increased in this way exchanges heat with the electric motor 4, the inverter 41, and the HV battery 42, the warming up of the electric motor 4, the inverter 41, and the HV battery 42 is promoted. In particular, the waste heat obtained from the internal combustion engine 3 can be actively used to warm up the electric motor 4, the inverter 41, and the HV battery 42 under conditions where the temperature of the second refrigerant is low, such as when starting in winter or in a cold region. . Further, since charging and discharging are possible when the inverter 41 and the HV battery 42 are warmed up, fuel consumption can be improved by warming up the inverter 41 and the HV battery 42 at an early stage. The ECU 21 returns after completing step S4.

ECU21 If judged NO in step S3, i.e., when the temperature _{T 2} of the second coolant is not less than the temperature _{T A,} the process proceeds to step S5. ECU21 in step S5, the temperature _{T 2} of the second refrigerant determined whether below the temperature _{T B (T B> T A} ). Temperature _{T B} is the motor 4 is operable upper limit temperature of the inverter 41, HV battery 42. ECU21 If judged YES in step S5, i.e., if the temperature _{T 2} of the second refrigerant is below the temperature _{T B,} the process proceeds to step S6.

ECU21 in step S6, the temperature _{T 1} of the first refrigerant is determined whether or temperature _{T C.} The temperature T _C is the second predetermined temperature. Temperature T _C is the upper limit temperature of the temperature of the first refrigerant suitable for supplying to the internal combustion engine 3. ECU21 If judged YES in step S6, namely, when the temperature _{T 1} of the first refrigerant is not less than a temperature _{T C,} the flow proceeds to step S4. In the case where YES is determined in step S6, and the temperature T ₁ of the first refrigerant is less than the upper limit temperature of the optimum temperature, temperature T ₂ is the electric motor 4 of the second refrigerant, the upper limit of the operable temperature of the inverter 41, HV battery 42 Below the temperature. At this time, the second refrigerant has a sufficient capacity to receive heat. Therefore, by introducing the second refrigerant into the condenser 35, the first refrigerant and the second refrigerant can exchange heat, and the first refrigerant can be cooled. Thereby, the condenser 35 can be cooled to an appropriate temperature. In particular, when the temperature of the second refrigerant is low, the amount of heat that the second refrigerant takes away from the first refrigerant increases, so that a high cooling capacity can be obtained. In this process, the temperature of the electric motor 4, the inverter 41, and the HV battery 42 is equal to or lower than the upper limit temperature when the cooling capacity of the condenser 35 by only the cooling fan 9 is insufficient in a situation where high load operation is continuously performed. And it is effective when there is a margin in the amount of heat received. The efficiency of the Rankine cycle system can be improved by cooling the first refrigerant with the second refrigerant.

Meanwhile, ECU 21 when it is determined that NO in the step S5, that is, when the temperature _{T 2} of the second coolant is not less than the temperature _{T B,} the process proceeds to step S7. In step S7, the ECU 21 stops introducing the second refrigerant into the condenser 35. Specifically, the operation of the electric pump 72 is stopped. Thereby, the flow of the second refrigerant in the second refrigerant passage 7 is stopped, and the heat exchange between the first refrigerant and the second refrigerant in the heat exchange pipe 71 is stopped. If the temperature T ₂ of the second coolant is not less than the temperature T _B, since the second refrigerant can not afford the volume receives heat, suppresses heat exchange between the first refrigerant and the second refrigerant. For this reason, the heat exchange between the first refrigerant and the second refrigerant is stopped.

Further, ECU 21 when it is determined that NO in step S6, namely, when the temperature _{T 1} of the first refrigerant is less than the temperature _{T C,} the flow proceeds to step S7. In case where NO is determined in step S6, but the second refrigerant is spare capacity to receive heat, the temperature T ₁ of the first coolant is in the state of an appropriate temperature, there is no need for cooling. Therefore, the heat exchange between the first refrigerant and the second refrigerant is stopped. The ECU 21 returns after completing step S7. The ECU 21 also returns when it determines NO in step S1. Further, separately from such a control process, the cooling fan 9 is appropriately operated to cool the first refrigerant. The electric motor 4, the inverter 41, and the HV battery 42 are also appropriately cooled by a separate cooling system and maintained at a temperature suitable for operation.

  With the above-described configuration and control, the Rankine cycle system apparatus 1 supplies the second refrigerant to the condenser 35 and exchanges heat with the vaporized first refrigerant. Thereby, the capability of cooling the first refrigerant of the condenser 35 is improved. Furthermore, since the amount of heat exchange between the first refrigerant and the atmosphere can be reduced in the condenser 35 by the amount of heat exchange between the first refrigerant and the second refrigerant, the condenser 35 can be reduced in size. In addition, since the flow rate of the air supplied to the condenser 35 can be reduced, the cooling fan 9 that forcibly supplies the air to the condenser 35 can be reduced in size and power consumption.

  Further, the second refrigerant receives heat from the first refrigerant and raises the temperature instead of cooling the first refrigerant. Thus, the 2nd refrigerant | coolant which temperature rose can warm up the electric motor 4, the inverter 41, and the HV battery 42 at the time of cold start. Therefore, the cooling capacity of the condenser 35 can be improved, and the electric motor 4, the inverter 41, and the HV battery 42 can be operated at an early stage to improve fuel efficiency.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope. In the above embodiment, the other power engine is a peripheral device incorporated together with the motor and the motor, but the other power engine is not limited to the above-described configuration, and is another power engine that can perform heat exchange. Including things.

1 Rankine cycle system device 2 Hybrid system 3 Internal combustion engine 4 Electric motor (part of other power engine)
DESCRIPTION OF SYMBOLS 5 1st refrigerant path 6 Waste heat recovery machine 7 2nd refrigerant path 9 Cooling fan 10 1st temperature sensor 21 ECU (control part)
35 Condenser 41 Inverter (part of other power engine)
42 HV battery (part of other power engines)
71 Heat exchange pipe (Heat exchange part)
73 Second temperature sensor (temperature measurement unit)

Claims (3)

A hybrid system comprising an internal combustion engine and another power engine;
A first refrigerant that circulates in the internal combustion engine and is vaporized by waste heat of the internal combustion engine;
A waste heat recovery machine that recovers energy of waste heat from the vaporized first refrigerant;
A condenser for cooling the vaporized first refrigerant;
A second refrigerant that exchanges heat with the other power engine;
A heat exchanging section for exchanging heat between the first refrigerant and the second refrigerant in the condenser;
A temperature measuring unit for measuring the temperature of the second refrigerant;
A control unit for introducing the second refrigerant into the heat exchange unit based on the temperature of the second refrigerant measured by the temperature measurement unit;
Rankine cycle system device equipped with.   The Rankine cycle system device according to claim 1, wherein the controller introduces the second refrigerant into the heat exchange unit when the temperature of the second refrigerant is lower than a first predetermined temperature.   3. The Rankine cycle system device according to claim 1, wherein the controller introduces the second refrigerant to the heat exchange unit when a temperature of the first refrigerant at an outlet of the condenser is equal to or higher than a second predetermined temperature. 4. .

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