JP2007205283A - Waste heat utilization device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste heat utilization device enabling efficient power generation by focusing on rotation speeds of an expander and a pump and to provide its control method. <P>SOLUTION: The waste heat utilization device comprises a Rankine cycle 300 having a heater 310 for heating coolant with a heat source of waste heat from heat generation equipment 10, the expander 320, a condenser 220 and the pump 330, a power generator 321 connected to the expander 320 and operated by driving force of the expander 320 to generate electric power, and a control means 500 for controlling operation of the power generator 321, wherein the pump 330 is connected to the expander 320. The control means 500 controls the operational rotation speed of the power generator 321 according to at least one of heating capacity of the heater 310 for the coolant, condensing capacity of the condenser 220 for the coolant and coolant pressure in the Rankine cycle 300. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a waste heat utilization apparatus that recovers power using waste heat of a heat-generating device and a control method thereof, and is suitable for use in, for example, a vehicle equipped with an internal combustion engine.

  For example, as shown in Patent Document 1, as a conventional waste heat utilization device (bottoming cycle power generation system in Patent Document 1), a Rankine cycle provided with a generator is known. The Rankine cycle consists of a pump that circulates the internal heat medium, a heat exchanger that heats the heat medium, an expander that rotates by the expansion of the heated heat medium (turbine), and heat dissipation that cools the expanded heat medium. The heat exchanger for use is connected in a ring shape. Here, a pump and a generator are connected to and integrated with the main shaft of the expander.

The heating heat exchanger is supplied with heating liquid or gas (gas turbine, engine exhaust, etc.). The heat medium sent from the pump becomes superheated steam in the heating heat exchanger, flows into the expander, and adiabatically expands in the expander to generate a driving force in the expander. Then, the pump and the generator connected by this driving force are operated, the operation of the Rankine cycle is continued, and the exhaust heat energy is stored as electric energy. The expanded heat medium is cooled and condensed by cooling air or the like in a heat radiating heat exchanger and sucked into a pump.
JP 2004-108220 A

  However, in the waste heat utilization apparatus, there is no specific mention of a method for determining the rotation speed of the expander and the pump.

  For example, if the number of revolutions is increased when the temperature of the heating liquid or gas is low, the flow rate of the heat medium increases, and the heating heat exchanger cannot evaporate, resulting in very poor power generation efficiency.

  In addition, for example, when the wind speed of the cooling air in the heat dissipation heat exchanger is low, if the rotation speed is increased, a large amount of heat is input in the heating heat exchanger, but the heat dissipation heat exchanger cannot radiate heat, The heat medium pressure in the heat radiating heat exchanger increases. Therefore, the pressure difference before and after the expander can no longer be taken, and the power generation efficiency becomes very poor.

  In view of the above problems, an object of the present invention is to provide a waste heat utilization apparatus and a control method thereof that enable efficient power generation by paying attention to the rotational speeds of an expander and a pump.

  In order to achieve the above object, the present invention employs the following technical means.

  In the first aspect of the invention, the heater (310) that heats the refrigerant using the waste heat of the heat generating device (10) as a heating source, and the expansion that is activated by the expansion of the superheated vapor refrigerant that flows out of the heater (310). (320), the condenser (220) that cools and condenses the expanded refrigerant flowing out from the expander (320) with a cooling medium, and the condensed refrigerant that flows out from the condenser (220) is pumped to the heater (310). A Rankine cycle (300) having a pump (330) for generating power, a generator (321) that is connected to the expander (320) and is activated by the driving force of the expander (320), and a generator (321) In the waste heat utilization apparatus in which the pump (330) is connected to the expander (320), the control means (500) includes a heater (3 The operating rotational speed of the generator (321) is controlled according to at least one of the heating capacity of 0), the condenser capacity of the condenser (220) with respect to the refrigerant, and the refrigerant pressure in the Rankine cycle (300). It is said.

  Thereby, since the generator (321) can be operated by the expander (320) while ensuring the heat balance in the Rankine cycle (300), efficient power generation is possible.

  As in the second aspect of the present invention, the waste heat utilization device (100) is an internal combustion engine (10), and the heating source is suitable as cooling water for cooling the internal combustion engine (10).

  In the invention according to claim 3, the control means (500) grasps the heating capacity from the temperature of the cooling water, and increases the operating rotational speed of the generator (321) as the temperature of the cooling water increases. It is a feature.

  Accordingly, when the flow rate of the cooling water is constant, the higher the cooling water temperature, the more waste heat energy is obtained in the refrigerant in the heater (310), and the expander (320) has a larger amount corresponding to the waste heat energy. Therefore, efficient power generation in the generator (321) becomes possible by increasing the operating rotational speed of the generator (321).

  In the invention according to claim 4, the control means (500) grasps the heating capacity by the flow rate of the cooling water, and increases the operating rotational speed of the generator (321) as the flow rate of the cooling water increases. It is a feature.

  As a result, when the temperature of the cooling water is kept constant, the larger the flow rate of the cooling water, the more waste heat energy is obtained in the refrigerant in the heater (310), and the expander (320) depends on the waste heat energy. Since much mechanical energy can be obtained, efficient power generation in the generator (321) becomes possible by increasing the operating rotational speed of the generator (321).

  In the invention described in claim 5, the cooling water is circulated through the internal combustion engine (10) by the pump means (22), and the control means (500) cools from the rotational speed of the pump means (22). It is characterized by estimating the water flow rate.

  As a result, the flow rate of the cooling water correlates with the rotational speed of the pump means (22). Therefore, the flow rate of the cooling water can be easily estimated from the rotational speed of the pump means (22) by grasping the relationship in advance. can do.

  In the invention as set forth in claim 6, the pump means (22) is driven by the power of the internal combustion engine (10), and the control means (500) sets the rotational speed of the pump means (22) to the internal combustion engine. It is characterized by estimating from the rotational speed of the engine (10).

  Thereby, since the rotation speed of the pump means (22) correlates with the rotation speed of the internal combustion engine (10), the pump means can be easily determined from the rotation speed of the internal combustion engine (10) by grasping the relationship in advance. The rotational speed of (22) can be estimated.

  In the seventh aspect of the present invention, the pump means (22) is driven by the power of the electric motor controlled by the electric motor control means, and the control means (500) is the pump means (22). It is characterized in that the rotational speed is estimated from the control value of the electric motor.

  Thereby, the rotation speed of a pump means (22) can be estimated easily.

  As in the eighth aspect of the invention, if the operation output of the electric motor is duty-controlled, the control value can be the voltage duty ratio of the electric motor.

  Further, as in the ninth aspect of the invention, when the operation output of the electric motor is inverter-controlled, the control value can be the frequency of the inverter voltage of the electric motor.

  In the invention according to claim 10, the cooling medium is outside air, and the control means (500) grasps the condensing capacity from the outside air temperature, and the lower the outside air temperature is, the lower the operating rotational speed of the generator (321). It is characterized by raising the height.

  As a result, if the flow rate of the outside air is constant, the lower the temperature of the outside air, the higher the condensing capacity in the condenser (220), and the condensation of the refrigerant that expands and flows out by the expander (320) is sufficiently performed. Since this can be covered, efficient power generation in the generator (321) becomes possible by increasing the operating speed of the generator (321).

  In the eleventh aspect of the invention, the cooling medium is the outside air, and the control means (500) grasps the condensing capacity from the flow rate of the outside air, and as the flow rate of the outside air increases, the operating rotational speed of the generator (321). It is characterized by raising the height.

  As a result, when the temperature of the outside air is constant, the higher the flow rate of the outside air, the higher the condensing capacity in the condenser (220), and the condensation of the refrigerant that expands and flows out by the expander (320) is sufficiently performed. Since this can be covered, efficient power generation in the generator (321) becomes possible by increasing the operating speed of the generator (321).

  The invention according to claim 12 is characterized in that the control means (500) estimates the flow rate of the outside air from the wind speed of the outside air.

  Thereby, the flow volume of outside air can be estimated easily.

  In the invention according to claim 13, the outside air is introduced into the condenser (220) by the vehicle speed wind of the vehicle, and the control means (500) It is characterized by estimating the flow rate.

  Thereby, similarly to the invention according to claim 12, the flow rate of the outside air can be easily estimated.

  The vehicle according to claim 13 is suitable for vehicles including general passenger cars, hybrid vehicles, and trucks as in the invention according to claim 14.

  In the invention according to claim 15, the control means (500) uses at least one of the high-pressure side pressure of the Rankine cycle (300) and the low-pressure side pressure of the Rankine cycle (300) as the refrigerant pressure, It is characterized in that the operating rotational speed of the generator (321) is increased as at least one of the side pressure and the low pressure side pressure is lower.

  As a result, the lower the at least one of the high-pressure side pressure and the low-pressure side pressure, the higher the heating capability or the condensation capability in at least one of the heater (310) and the condenser (220). That is, a lot of waste heat energy is obtained in the refrigerant in the heater (310), and more mechanical energy corresponding to the waste heat energy can be obtained in the expander (320). Alternatively, the condenser (220) can sufficiently cover the condensation of the refrigerant that expands and flows out by the expander (320). Therefore, efficient power generation in the generator (321) becomes possible by increasing the operating rotational speed of the generator (321).

  In the invention according to claim 16, the control means (500) sets the temperature of the cooling water, the flow rate of the cooling water, the temperature of the outside air, the flow rate of the outside air, the refrigerant when setting the operating rotational speed of the generator (321). Of the pressure values, two or more values are used, and among the operating rotational speeds calculated from the two or more values, the operating rotational speed of the generator (321) is determined using the minimum value. It is characterized by that.

  As a result, the possibility of power generation under better conditions can be ensured, and the generator (321) can be operated under conditions that are safe with respect to the heat balance of the Rankine cycle (300), preventing excessive power generation. can do.

  The invention according to claim 17 includes a refrigeration cycle (200) having a compressor (210), an air conditioner condenser (220A), an expansion valve (240), and an evaporator (250), and the condenser (220); The air conditioner condenser (220A) is shared.

  Thereby, the setting of an air-conditioner condenser (220A) can be reduced and a refrigerating cycle (200) can be provided compactly.

  The invention described in claims 18 to 34 relates to a control method in the waste heat utilization apparatus (100), and its technical significance is essentially the same as that of the waste heat utilization apparatus described in claims 1 to 17. Are the same.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

(First embodiment)
A first embodiment of the present invention is shown in FIGS. 1 to 8, and a specific configuration will be described first. The waste heat utilization apparatus 100 of the present invention is applied to a general passenger car (vehicle) using the engine 10 as a drive source. The Rankine cycle 300 including the motor generator 321 and the Rankine cycle 300 (motor generator 321). And a control device 500 (500a to 500d) for controlling the operation of. The vehicle is equipped with a refrigeration cycle 200 that shares some of the equipment (condenser 220, gas-liquid separator 230, and subcooler 231) in the Rankine cycle 300.

  As shown in FIG. 1, the engine 10 is a water-cooled internal combustion engine (corresponding to the heat generating device in the present invention), and a radiator circuit 20 that cools the engine 10 by circulation of engine cooling water, and cooling water (hot water). A heater circuit 30 for heating the conditioned air is provided as a heat source. The engine 10 is provided with an alternator 11 that is driven by the driving force of the engine 10 transmitted through the belt 12 to generate electric power. The electric power generated by the alternator 11 is charged in the battery 40, and the electric power charged in the battery 40 is supplied to a vehicle electrical load (headlamp, wiper, audio, etc.) 41.

  The radiator circuit 20 is provided with a radiator 21. The radiator 21 cools the cooling water circulated by a hot water pump (corresponding to the pump means in the present invention) 22 by heat exchange with outside air. Here, the hot water pump 22 is a mechanical pump driven by the engine 10 and is operated at a predetermined rotation speed ratio with respect to the rotation speed of the engine 10 (hereinafter referred to as engine rotation speed). The engine 10 is provided with a rotation speed sensor 13 for detecting the engine rotation speed, and a rotation speed signal detected by the rotation speed sensor 13 is output to a control device 500 (vehicle control ECU 500b) described later. It has come to be.

  In addition, a water temperature sensor 25 and a heater 310 of a Rankine cycle 300 to be described later are disposed in a flow path on the outlet side of the engine 10 (flow path between the engine 10 and the radiator 21). The water temperature sensor 25 is a water temperature detecting means for detecting the cooling water temperature on the outlet side of the engine 10, and a temperature signal detected by the water temperature sensor 25 is output to a control device 500 (system control ECU 500a) described later. It has become. Further, cooling water flowing out from the engine 10 circulates in the heater 310.

  The radiator circuit 20 is provided with a radiator bypass passage 23 through which the coolant flows around the radiator 21, and the coolant flow through the radiator 21 and the radiator bypass passage 23 are circulated by the thermostat 24. The cooling water flow rate is adjusted.

  A heater core 31 is provided in the heater circuit 30, and cooling water (hot water) is circulated by the hot water pump 22. The heater core 31 is disposed in the air conditioning case 410 of the air conditioning unit 400, and heats the conditioned air blown by the blower 420 by heat exchange with hot water. The heater core 31 is provided with an air mix door 430, and the amount of conditioned air passing through the heater core 31 is adjusted by opening and closing the air mix door 430.

  The Rankine cycle 300 collects waste heat energy (cooling water heat energy) generated in the engine 10 and converts the waste heat energy into electric energy for use. Hereinafter, the Rankine cycle 300 will be described.

  The Rankine cycle 300 includes a heater 310, an expander 320, a condenser 220, a gas-liquid separator 230, a supercooler 231, and a pump 330, which are sequentially connected to form a closed circuit.

  In the Rankine cycle 300, a motor generator (corresponding to a generator in the present invention) 321 having both functions of an electric motor and a generator is connected to the expander 320, and a pump 330 is connected to the expander 320. It has become. Specifically, one end side of the motor generator 321 is connected to the expander 320, and the other end side of the motor generator 321 is connected to the pump 330, so that the expander 320, the motor generator 321 and the pump 330 are integrated. Is formed.

  The operation of the motor generator 321 is controlled by a control device 500 (inverter 500d) described later. That is, the motor generator 321 drives (activates) the expander 320 and the pump 330 as motors when electric power is supplied from an inverter 500d described later. The motor generator 321 operates as a generator when receiving a driving force from the expander 320. At this time, the rotational speed of the motor generator 321 is controlled by the inverter 500d (details will be described later), and the power generation amount is adjusted accordingly. The generated power is charged into the battery 40 by the inverter 500d.

  The pump 330 is a fluid device that circulates the refrigerant in the Rankine cycle 300 and is operated by the driving force of the expander 320. The heater 310 is a heat exchanger that heats the refrigerant by exchanging heat between the refrigerant sent from the pump 330 and the high-temperature cooling water (corresponding to the heating source in the present invention) flowing through the radiator circuit 20. The expander 320 is a fluid device that generates a rotational driving force by the expansion of the superheated steam refrigerant heated by the heater 310.

  The condenser 220 is a heat exchanger that condenses and liquefies the refrigerant by heat exchange with outside air as a cooling medium, and is disposed, for example, in the front of the vehicle engine room. The vehicle speed wind at the time of traveling of the vehicle flows into the heat exchange part of the condenser 220 as outside air. The inflow of outside air increases according to the vehicle speed (vehicle speed). The gas-liquid separator 230 is a receiver that separates the refrigerant condensed in the condenser 220 into gas-liquid two layers. The subcooler 231 is a heat exchanger that further cools the liquid refrigerant flowing out of the gas-liquid separator 231. The condenser 220, the gas-liquid separator 230, and the supercooler 231 are in the form of a subcool condenser having a so-called gas-liquid separator. The condenser 220, the gas-liquid separator 230, and the supercooler 231 may be a gas-liquid separator integrated subcool condenser that is integrally formed.

  And between the pump 330 and the heater 310, the refrigerant | coolant pressure sensor 341 as a pressure detection means which detects the refrigerant | coolant pressure (henceforth a high voltage | pressure side pressure) used as the high voltage | pressure side of the Rankine cycle 300 is provided. The pressure signal detected by the refrigerant pressure sensor 341 is output to a control device 500 (system control ECU 500a) described later.

  In addition, a refrigerant pressure sensor 342 is provided between the supercooler 231 and the pump 330 as pressure detection means for detecting a refrigerant pressure on the low pressure side of the Rankine cycle 300 (hereinafter, low pressure side pressure). The pressure signal detected by the refrigerant pressure sensor 342 is output to a control device 500 (system control ECU 500a) described later.

  The refrigeration cycle 200 includes a compressor 210, a condenser 220, a gas-liquid separator 230, a supercooler 231, an expansion valve 240, and an evaporator 250, which are sequentially connected in a ring to form a closed circuit. . The condenser 220, the gas-liquid separator 230, and the supercooler 231 are commonly used in the Rankine cycle 300, and the working fluid that circulates in the refrigeration cycle 200 is the same as the refrigerant in the Rankine cycle 300. It has become a thing.

  The compressor 210 is a fluid device that compresses the refrigerant in the refrigeration cycle 200 to a high temperature and a high pressure. Here, the compressor 210 is driven by the driving force of the engine 10. That is, a pulley 211 as a driving means is fixed to the drive shaft of the compressor 210, and the driving force of the engine 10 is transmitted to the pulley 211 via the belt 12 to drive the compressor 210. The pulley 211 is provided with an electromagnetic clutch 212 that connects and disconnects between the compressor 210 and the pulley 211. The on / off state of the electromagnetic clutch 212 is controlled by a control device 500 (air conditioner control ECU 500c) described later.

  The refrigerant discharge side of the compressor 210 is connected so as to merge with the condenser 220, and is branched from the Rankine cycle 300 on the refrigerant outflow side of the subcooler 231 and connected to the expansion valve 240.

  The expansion valve 240 is a decompression unit that decompresses and expands the liquid refrigerant flowing out from the supercooler 231. In this embodiment, the expansion valve 240 decompresses the refrigerant in an enthalpy manner, and also superheats the refrigerant sucked into the compressor 210. A temperature type expansion valve that controls the opening degree of the throttle so that becomes a predetermined value is employed.

  The evaporator 250 is disposed in the air conditioning case 410 of the air conditioning unit 400 in the same manner as the heater core 31. The evaporator 250 is a heat exchanger that evaporates the refrigerant decompressed and expanded by the expansion valve 240 and cools the conditioned air from the blower 420 by the latent heat of evaporation at that time. The refrigerant outlet side of the evaporator 250 is connected to the suction side of the compressor 210. Note that the mixing ratio of the conditioned air cooled by the evaporator 250 and the conditioned air heated by the heater core 31 is adjusted according to the opening of the air mix door 430 and adjusted to a temperature set by the occupant.

  A control device (corresponding to the control means in the present invention) 500 is a control means for controlling the operation of various devices of the Rankine cycle 300 and the refrigeration cycle 200, and includes a system control ECU 500a, a vehicle control ECU 500b, an air conditioner control ECU 500c, and an inverter 500d. have.

  A vehicle control ECU 500b, an air conditioner control ECU 500c, and an inverter 500d are connected to the system control ECU 500a, and control signals are exchanged between them. The system control ECU 500a receives a detection signal from an outside air temperature sensor 510 as outside air temperature detecting means for detecting the outside air temperature.

  The system control ECU 500a performs overall control of the Rankine cycle 300 and the refrigeration cycle 200, and controls the operation of the motor generator 321 according to various conditions that contribute to the operating state of the Rankine cycle 300 as described later ( Details will be described later).

  The vehicle control ECU 500b mainly controls the engine 10, and is an engine load (engine torque) calculated from the coolant temperature from the water temperature sensor 25, the engine speed from the rotation speed sensor 13, the throttle valve opening, and the like. ) And the like, the fuel injection amount (fuel supply amount) is controlled so that the combustion efficiency of the fuel (gasoline) is optimized. The vehicle control ECU 500b calculates the speed of the vehicle, that is, the vehicle speed, from the engine speed, the transmission gear ratio (not shown), and the like.

  The air conditioner control ECU 500c controls the basic operation of the refrigeration cycle 200 according to the passenger's air conditioner request, set temperature, environmental conditions, and the like. The inverter 500d controls the operation of the Rankine cycle 300 by operating the motor generator 321 as an electric motor or a generator and adjusting the number of rotations thereof.

  Next, the operation of the waste heat utilization apparatus 100 based on the above configuration will be described. In this waste heat utilization apparatus 100, in addition to the following Rankine cycle single operation, simultaneous operation of Rankine cycle and refrigeration cycle and refrigeration cycle single operation are enabled.

1. Rankine cycle independent operation control device 500 disconnects electromagnetic clutch 212 (compressor 210) when it is determined that there is no air conditioner request and the cooling water temperature is equal to or higher than the predetermined cooling water temperature and sufficient waste heat of engine 10 is obtained. And the motor generator 321 is first actuated (activated) as an electric motor (by operating the expander 320 and the pump 330), and the Rankine cycle 300 is operated. Then, power is generated by the power generation action of the motor generator 321 accompanying the rotational driving force of the expander 320.

  More specifically, the liquid refrigerant from the supercooler 231 is boosted by the pump 330 and sent to the heater 310, where the liquid refrigerant is heated by the high-temperature engine cooling water and expands as superheated steam refrigerant. Sent to the machine 320. In the expander 320, the superheated vapor refrigerant is expanded and reduced in an isentropic manner, and part of the heat energy and pressure energy is converted into a rotational driving force, and the motor generator 321 is driven by the rotational driving force extracted by the expander 320. Actuated. When the rotational driving force in the expander 320 exceeds the driving force for the pump 330, the motor generator 321 operates as a generator that generates electric power, and the obtained electric power is supplied to the battery 40 via the inverter 500d. Charged. The charged electric power is used for the operation of the vehicle electric load 41. Therefore, the load on the alternator 11 is reduced. Note that the refrigerant decompressed by the expander 320 is condensed by the condenser 220, separated into gas and liquid by the gas / liquid separator 230, supercooled by the subcooler 231, and sucked into the pump 330 again.

2. Simultaneous operation of the Rankine cycle and the refrigeration cycle When the controller 500 determines that sufficient waste heat is obtained and that there is an air conditioner request, the Rankine cycle 300 and the refrigeration cycle 200 are operated simultaneously to generate power and air conditioning. Do both.

  In this case, the electromagnetic clutch 212 is connected and the motor generator 321 (expander 320, pump 330) is operated. Then, the refrigerant discharged from the expander 320 and the compressor 210 merges and flows through the condenser 220, the gas-liquid separator 230, and the supercooler 231, and then branches to the pump 330 side and the expansion valve 240 side. Then, the two cycles 300 and 200 are circulated. The operation content of the Rankine cycle 300 is the same as that of the Rankine cycle single operation. In the refrigeration cycle 200, the conditioned air is cooled by the evaporator 250. The cooled conditioned air and the conditioned air heated by the heater core 31 are mixed at a predetermined ratio by the air mix door 430 and adjusted to a temperature set by the occupant.

3. The refrigeration cycle single operation control device 500 is a case where sufficient waste heat cannot be obtained during warming up immediately after the engine 10 is started, that is, when the cooling water temperature obtained by the water temperature sensor 25 is less than a predetermined cooling water temperature. When it is determined that there is an air conditioner request from the occupant, the motor generator 321 is stopped (the expander 320 and the pump 330 are stopped), the electromagnetic clutch 212 is connected, and the compressor 210 is driven by the driving force of the engine 10. The refrigeration cycle 200 is operated alone.

  In the present embodiment, the rotational speed of the motor generator 321 is controlled according to various conditions that contribute to the operating state during the operation of the Rankine cycle 300, and will be described in detail below with reference to FIGS. To do.

  FIG. 2 is a control flow for controlling the rotational speed of the motor generator 321 when the control device 500 operates the Rankine cycle 300. At the time of operation of Rankine cycle 300, control device 500 first reads various data in step S100. The various data are the coolant temperature (Tw) obtained from the water temperature sensor 25, the engine speed (Ne) obtained from the rotational speed sensor 13, the outside air temperature (TA) obtained from the outside air temperature sensor 510, and the vehicle control ECU 500b. The vehicle speed (Vv) obtained, the high pressure side pressure (Pr) obtained from the refrigerant pressure sensor 341, and the low pressure side pressure (Ph) obtained from the refrigerant pressure sensor 342.

  In step S110, the rotational speed (N) corresponding to each data is calculated using the control characteristic diagrams shown in FIGS.

  The control characteristic diagram shown in FIG. 3 is to calculate the optimum rotation speed Ntw of the expander 320 and the pump 330 with respect to the cooling water temperature. This is because if the cooling water flow rate is constant, the higher the cooling water temperature, the higher the heating capacity in the heater 310 and the more waste heat energy can be recovered, so the rotation speed Ntw is set higher. Is. A value corresponding to the cooling water temperature obtained from the water temperature sensor 25 is calculated as the rotation speed Ntw using this control characteristic diagram. Note that the rotation speed of the expander 320 and the pump 330 can be a minimum rotation speed (Nmin) to a maximum rotation speed (Nmin) as a design specification. Thus, hysteresis is provided between the minimum cooling water temperature (Twmin) and a predetermined value + α.

  The control characteristic diagram shown in FIG. 4 is for calculating the optimum rotation speed Nqw of the expander 320 and the pump 330 with respect to the engine rotation speed. Here, the engine speed is taken as the flow rate of the cooling water. That is, the flow rate of the cooling water is proportional to the number of revolutions of the hot water pump 22, and the warm water pump 22 is a mechanical pump driven by the engine 10, so that the number of revolutions of the hot water pump 22 is the engine speed. It is proportional to the number. Therefore, the flow rate of the cooling water, which is difficult to grasp directly, can be captured by the engine speed.

  In the above control characteristic diagram, if the cooling water temperature is constant, the higher the engine speed (cooling water flow rate), the higher the heating capacity in the heater 310 and the more waste heat energy can be recovered. Is set higher. Then, using this control characteristic diagram, a value corresponding to the engine speed obtained from the speed sensor 13 is calculated as the speed Nqw. As in the control characteristic diagram of FIG. 3, in the control characteristic diagram of FIG. 4, a hysteresis is provided between the minimum engine speed (Nemin) and the predetermined value + α on the minimum speed (Nmin) side. I have to.

  The control characteristic diagram shown in FIG. 5 is for calculating the optimum rotation speed Nta of the expander 320 and the pump 330 with respect to the outside air temperature. This is because if the outside air flow rate is constant, the lower the outside air temperature, the higher the condensing capacity of the condenser 220 and the sufficient condensation of the refrigerant flowing out of the expander 310. It is set to be high. Using this control characteristic diagram, a value corresponding to the outside air temperature obtained from the outside air temperature sensor 510 is calculated as the rotation speed Nta. As in the control characteristic diagram of FIG. 3, in the control characteristic diagram of FIG. 5, a hysteresis is provided between the maximum outside air temperature (TAmax) and the predetermined value −α on the minimum rotational speed (Nmin) side. I have to.

  The control characteristic diagram shown in FIG. 6 is for calculating the optimum rotation speed Nvv of the expander 320 and the pump 330 with respect to the vehicle speed. Here, the vehicle speed is taken as the flow rate of outside air flowing into the condenser 220. That is, the flow rate of the outside air is proportional to the wind speed of the outside air, and the wind speed of the outside air is proportional to the vehicle speed. Therefore, the flow rate of outside air can be captured at the vehicle speed.

  In the above control characteristic diagram, if the outside air temperature is constant, the higher the vehicle speed (outside air flow rate), the higher the condensing capacity in the condenser 220, so that the refrigerant flowing out of the expander 310 can be sufficiently covered. The rotation speed Nvv is set higher. Then, using this control characteristic diagram, a value corresponding to the vehicle speed calculated by the vehicle control ECU 500b is calculated as the rotation speed Nvv. Similar to the control characteristic diagram of FIG. 3, in the control characteristic diagram of FIG. 6, a hysteresis is provided between the minimum vehicle speed (Vvmin) and the predetermined value + α on the minimum speed (Nmin) side. Yes.

  The control characteristic diagram shown in FIG. 7 is to calculate the optimum rotation speed Nph of the expander 320 and the pump 330 with respect to the low-pressure side pressure of the Rankine cycle 300. This is because the condensing capacity in the condenser 220 becomes higher as the pressure on the low pressure side becomes lower, and the condensation of the refrigerant flowing out of the expander 310 can be sufficiently covered, so the rotational speed Nph is set higher. is there. A value corresponding to the low-pressure side pressure obtained from the refrigerant pressure sensor 342 is calculated as the rotation speed Nph using this control characteristic diagram. Similar to the control characteristic diagram of FIG. 3, in the control characteristic diagram of FIG. 7, hysteresis is provided between the maximum pressure (Phmax) and the predetermined value −α on the minimum rotational speed (Nmin) side. . When the refrigeration cycle 200 is operated due to an air conditioner request, the condensing capacity of the condenser 220 is also used for the refrigeration cycle 200, so the low-pressure side pressure is increased and the rotational speed Nph is set low. The operation of Rankine cycle 300 is limited. Accordingly, it is possible to prevent the efficiency of the refrigeration cycle 200 from being deteriorated by the Rankine cycle 300 and the compressor 210 of the refrigeration cycle 200 being consumed excessively.

  The control characteristic diagram shown in FIG. 8 is to calculate the optimum rotation speed Npr of the expander 320 and the pump 330 with respect to the high pressure side pressure of the Rankine cycle 300. This is because the lower the high-pressure side pressure, the lower the refrigerant temperature, the higher the heating capacity in the heater 310, and the more waste heat energy can be recovered, so the rotational speed Npr is set higher. . On the contrary, the higher the high-pressure side pressure, the lower the heating capacity and the more the pressure resistance of the Rankine cycle 300 becomes less, so the rotation speed Npr is set lower. Using this control characteristic diagram, a value corresponding to the high-pressure side pressure obtained from the refrigerant pressure sensor 341 is calculated as the rotation speed Npr. Similar to the control characteristic diagram of FIG. 3, in the control characteristic diagram of FIG. 8, a hysteresis is provided between the maximum pressure (Prmax) and the predetermined value −α on the minimum rotational speed (Nmin) side. ing.

  Since the motor generator 321 is connected to the expander 320 and the pump 330, the rotational speeds Ntw, Nqw, Nta, Nvv, Nph, and Npr calculated in the control characteristic diagrams of FIGS. This is the number of rotations to be controlled for the motor generator 321.

  In step S120, the control rotational speed Nmg of the motor generator 321 is determined. Here, it is determined as Nmg = MIN (Ntw, Nqw, Nta, Nvv, Nph, Npr). That is, among the rotation speeds Ntw, Nqw, Nta, Nvv, Nph, and Npr calculated above, the minimum rotation speed is set as the control rotation speed Nmg.

  In step S130, the inverter 500d adjusts so that the operating rotational speed of the motor generator 321 becomes the control rotational speed Nmg.

  As a result, the motor generator 321 can be operated by the expander 320 while ensuring the heat balance in the Rankine cycle 300, so that efficient power generation is possible.

  Here, the rotation speed to be controlled by the motor generator 321 is calculated using a plurality of data (cooling water temperature, engine rotation speed, outside air temperature, vehicle speed, high pressure side pressure, low pressure side pressure), and the calculated rotation Since the minimum value is used among the numbers (Ntw, Nqw, Nta, Nvv, Nph, Npr), the possibility of power generation under better conditions can be ensured and the heat balance of the Rankine cycle 300 can be secured. The motor generator 321 can be operated under safe conditions, and excessive power generation can be prevented.

  In addition, since the control characteristic diagrams (FIGS. 2 to 8) for calculating the number of rotations (Ntw, Nqw, Nta, Nvv, Nph, Npr) to be controlled have hysteresis, the minimum rotation It is possible to prevent hunting of the OFF state or ONN state of the motor generator 321 due to minute fluctuations of various data on the number (Nmin) side, and stable control becomes possible.

  In addition, the flow rate of the cooling water flowing through the heater 310 is regarded as the rotational speed of the hot water pump 22, and the rotational speed of the hot water pump 22 is captured based on the engine rotational speed. The above control can be calculated by estimation.

  In addition, since the flow rate of the outside air flowing into the condenser 220 is regarded as the wind speed and further as the vehicle speed, the flow rate of the outside air can be easily estimated to perform the above calculation.

  In addition, the control rotation speed of the motor generator 321 is determined in consideration of the high pressure side pressure of the Rankine cycle 300. When the high pressure side pressure is high, the rotation speed of the motor generator 321 is controlled to the low side. Therefore, the reliability related to the pressure resistance of the Rankine cycle 300 can be improved.

  In addition, since the refrigeration cycle 200 is formed by sharing the condenser 220 (gas-liquid separator 230, supercooler 231) of the Rankine cycle 300, the setting of dedicated equipment for the refrigeration cycle 200 is reduced, The refrigeration cycle 200 can be made compact.

(Second Embodiment)
For the determination of the control rotation speed Nmg with respect to the first embodiment, Nmg = (Ntw, Nqw, Nph, Npr), and the conditions of the rotation speed Nta associated with the outside air temperature and the rotation speed Nvv associated with the vehicle speed are omitted. May be.

  That is, in the condenser 220, the higher the outside air temperature, the lower the condensing capacity and the higher the condensing temperature, and accordingly the low pressure side pressure increases. Further, the lower the vehicle speed, the lower the flow rate of outside air, the lower the condensing capacity, and accordingly the low pressure side pressure increases. That is, since the outside air temperature and the vehicle speed are included in the low pressure side pressure, if the low pressure side pressure condition is used during the control, the outside air temperature and the vehicle speed can be omitted.

  This eliminates the need to detect the outside air temperature and the vehicle speed (no need to set the outside air temperature sensor 510), further simplifies the calculation in the control flow described in FIG. 2, and simplifies the control of the motor generator 321. be able to.

(Third embodiment)
A third embodiment of the present invention is shown in FIG. The refrigeration cycle 200 of the first embodiment may be a refrigeration cycle 200 </ b> A formed independently of the Rankine cycle 300 by providing a dedicated air conditioner condenser 220 </ b> A and a gas-liquid separator 230 </ b> A. The control of the motor generator 321 is performed in the same manner as in the first embodiment or the second embodiment. Thereby, the effect similar to the said 1st, 2nd embodiment can be acquired.

(Other embodiments)
In the first to third embodiments, the controlled rotation of the motor generator 321 is based on a plurality of (six) data such as cooling water temperature, engine speed, outside air temperature, vehicle speed, high pressure side pressure, and low pressure side pressure. Although the number is determined, it may be executed using one of the plurality of data or using two or more (two, three, four, five).

  Further, in controlling the rotational speed of the motor generator 321, the flow rate of the cooling water is estimated from the engine rotational speed by using the hot water pump 22 as a mechanical pump driven by the engine 10, but the hot water pump 22 is driven by the electric motor. As the electric pump to be driven, the flow rate of the cooling water may be estimated by grasping the pump rotation speed from the control value of the electric motor. For example, if duty control is performed on the operation output of the electric motor, the voltage duty ratio at that time can be regarded as the pump rotation speed. Or if the operation output of an electric motor is inverter-controlled, the frequency of the inverter voltage at that time can be grasped as a pump rotation speed.

  Further, the flow rate of the cooling water may be directly grasped by providing flow rate detection means such as a flow rate counter in the radiator circuit 20.

  In addition, the flow rate of the outside air in the condenser 220 is estimated from the vehicle speed. Instead, the wind speed of the outside air flowing into the condenser 220 is directly detected by a wind speed sensor or the like, and thus obtained. You may make it grasp | ascertain the flow volume of external air using a wind speed.

  Further, although the vehicle engine (internal combustion engine) 10 is used as the heat generating device, the heat generating device is not limited to this. For example, an external combustion engine, a fuel cell stack of a fuel cell vehicle, various motors, an inverter, and the like generate heat during operation. Along with this, any part of the heat for temperature control (those that generate waste heat) can be widely applied. In that case, the heating source for the heater 310 is a fluid for cooling various waste heat equipment.

  Further, the cooling medium in the condenser 220 is not limited to the outside air, but may be other cooling fluid (cooling water or the like).

  Moreover, you may abolish the supercooler 231 as needed.

  In addition, the Rankine cycle 300 (and the refrigeration cycle 200) has been described as being mounted on a general passenger car. However, the target vehicle is not limited to this, and can be widely applied to other vehicles such as hybrid vehicles, trucks, and buses. Applicable.

  In addition, when the Rankine cycle 300 and the refrigeration cycle 200 are operated during operation, the operating rotational speed of the motor generator 321 is controlled so as to keep the output of the Rankine cycle 300 low compared to the case where the Rankine cycle 300 is operated alone. You may make it do. Accordingly, it is possible to prevent the efficiency of the refrigeration cycle 200 from being deteriorated by the Rankine cycle 300 and the compressor 210 of the refrigeration cycle 200 being consumed excessively.

Further, in each of the above embodiments, the waste heat utilization apparatus 100 in which the pump 330 that pumps the condensed refrigerant flowing out from the condenser 220 to the heater 310 is connected to the expander 320 has been described. 320 can be driven separately, and the controller 500 controls the operating speed of the pump 330 according to at least one of the heating capacity of the heater 310, the condensation capacity of the condenser 220, and the refrigerant pressure in the Rankine cycle 300. Even if it is controlled, efficient power generation becomes possible.

It is a schematic diagram which shows the whole waste heat utilization apparatus in 1st Embodiment. It is a control flow of the motor generator which the control apparatus in 1st Embodiment performs. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the cooling water temperature in a 1st embodiment. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the engine number of rotations in a 1st embodiment. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the outside temperature in a 1st embodiment. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the vehicle speed in a 1st embodiment. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the low-pressure side pressure in a 1st embodiment. It is a control characteristic figure which calculates the optimal number of rotations corresponding to the high-pressure side pressure in a 1st embodiment. It is a schematic diagram which shows the whole waste heat utilization apparatus in 3rd Embodiment.

Explanation of symbols

10 Engine (heat generating equipment, internal combustion engine)
22 Hot water pump (pump means)
DESCRIPTION OF SYMBOLS 100 Waste heat utilization apparatus 200 Refrigeration cycle 210 Compressor 220 Condenser 220A Air-conditioner condenser 240 Expansion valve 250 Evaporator 300 Rankine cycle 310 Heater 320 Expander 321 Motor generator (generator)
330 Pump 500 Control device (control means)

Claims (34)

A heater (310) for heating the refrigerant using waste heat of the heat generating device (10) as a heating source, an expander (320) operated by expansion of superheated steam refrigerant flowing out from the heater (310), and the expander A condenser (220) that cools and condenses the expanded refrigerant flowing out from (320) with a cooling medium, and a pump (330) that pumps the condensed refrigerant flowing out from the condenser (220) to the heater (310) A Rankine cycle (300) having
A generator (321) that is connected to the expander (320) and is activated by the driving force of the expander (320) to generate electric power;
Control means (500) for controlling the operation of the generator (321),
In the waste heat utilization apparatus in which the pump (330) is connected to the expander (320),
The control means (500) includes at least one of a heating capacity of the heater (310) with respect to the refrigerant, a condensing capacity of the condenser (220) with respect to the refrigerant, and a refrigerant pressure in the Rankine cycle (300). The waste heat utilization apparatus characterized by controlling the operation | movement rotation speed of the said generator (321) according to. The heat generating device (10) is an internal combustion engine (10),
The waste heat utilization apparatus according to claim 1, wherein the heating source is cooling water for cooling the internal combustion engine (10).   The said control means (500) grasps | ascertains the said heating capability with the temperature of the said cooling water, and makes the working rotation speed of the said generator (321) high, so that the temperature of the said cooling water is high. Item 3. A waste heat utilization apparatus according to Item 2.   The said control means (500) grasps | ascertains the said heating capability with the flow volume of the said cooling water, and makes the working rotation speed of the said generator (321) high, so that the flow volume of the said cooling water is large. Item 3. A waste heat utilization apparatus according to Item 2. The cooling water is circulated through the internal combustion engine (10) by a pump means (22),
The waste heat utilization apparatus according to claim 4, wherein the control means (500) estimates the flow rate of the cooling water from the rotational speed of the pump means (22). The pump means (22) is driven by the power of the internal combustion engine (10),
The waste heat utilization apparatus according to claim 5, wherein the control means (500) estimates the rotational speed of the pump means (22) from the rotational speed of the internal combustion engine (10). The pump means (22) is driven by the power of the electric motor that is controlled by the electric motor control means,
The waste heat utilization apparatus according to claim 5, wherein the control means (500) estimates the rotational speed of the pump means (22) from a control value of the electric motor. The electric motor is one whose operation output is duty controlled,
The waste heat utilization apparatus according to claim 7, wherein the control value is a voltage duty ratio of the electric motor. The electric motor is an inverter whose operation output is controlled by an inverter,
The waste heat utilization apparatus according to claim 7, wherein the control value is a frequency of an inverter voltage of the electric motor. The cooling medium is outside air;
The said control means (500) grasps | ascertains the said condensation capacity | capacitance by the temperature of the said outside air, and makes the working rotation speed of the said generator (321) high, so that the temperature of the said outside air is low. The waste heat utilization device described in 1. The cooling medium is outside air;
The said control means (500) grasps | ascertains the said condensation capacity | capacitance with the flow volume of the said outside air, and makes the working rotation speed of the said generator (321) high, so that the flow volume of the said outside air is large. The waste heat utilization device described in 1.   The waste heat utilization apparatus according to claim 11, wherein the control means (500) estimates a flow rate of the outside air from a wind speed of the outside air. Mounted on a vehicle, the outside air is introduced into the condenser (220) by the vehicle speed wind of the vehicle,
The waste heat utilization apparatus according to claim 11, wherein the control means (500) estimates the flow rate of the outside air from a vehicle speed of the vehicle.   The waste heat utilization apparatus according to claim 13, wherein the vehicle includes a general passenger car, a hybrid vehicle, and a truck. The control means (500) uses at least one of the high pressure side pressure of the Rankine cycle (300) and the low pressure side pressure of the Rankine cycle (300) as the refrigerant pressure,
The waste heat utilization apparatus according to claim 1, wherein the operating rotational speed of the generator (321) is increased as at least one of the high-pressure side pressure and the low-pressure side pressure is low. When the operating speed of the generator (321) is set, the control means (500) sets the temperature of the cooling water, the flow rate of the cooling water, the temperature of the outside air, the flow rate of the outside air, and the refrigerant pressure. Two or more values are used among the values,
The operating rotational speed of the generator (321) is determined using the minimum value among the operating rotational speeds calculated from the two or more values. The waste heat utilization apparatus of Claim 11, Claim 15. A refrigeration cycle (200) having a compressor (210), an air conditioner condenser (220A), an expansion valve (240), and an evaporator (250);
The waste heat utilization apparatus according to any one of claims 1 to 16, wherein the condenser (220) and the air conditioner condenser (220A) are shared. A heater (310) for heating the refrigerant using waste heat of the heat generating device (10) as a heating source, an expander (320) operated by expansion of superheated steam refrigerant flowing out from the heater (310), and the expander A condenser (220) that cools and condenses the expanded refrigerant flowing out from (320) with a cooling medium, and a pump (330) that pumps the condensed refrigerant flowing out from the condenser (220) to the heater (310) A Rankine cycle (300) having
A generator (321) that is connected to the expander (320) and that is operated by the driving force of the expander (320) to generate electric power;
The pump (330) is a method for controlling a waste heat utilization apparatus connected to the expander (320),
The generator (321) according to at least one of the heating capacity of the heater (310) with respect to the refrigerant, the condensation capacity of the condenser (220) with respect to the refrigerant, and the refrigerant pressure in the Rankine cycle (300). The control method of the waste heat utilization apparatus characterized by controlling the operation | movement rotation speed of (3). The heat generating device (10) is an internal combustion engine (10),
The method of controlling a waste heat utilization apparatus according to claim 18, wherein the heating source is cooling water for cooling the internal combustion engine (10).   The use of waste heat according to claim 19, wherein the heating capacity is grasped by the temperature of the cooling water, and the operating speed of the generator (321) is increased as the temperature of the cooling water is higher. Control method of the device.   The use of waste heat according to claim 19, wherein the heating capacity is grasped by the flow rate of the cooling water, and the operating rotational speed of the generator (321) is increased as the flow rate of the cooling water is increased. Control method of the device. The cooling water is circulated through the internal combustion engine (10) by a pump means (22),
The method for controlling a waste heat utilization apparatus according to claim 21, wherein the flow rate of the cooling water is estimated from the rotational speed of the pump means (22). The pump means (22) is driven by the power of the internal combustion engine (10),
23. The method for controlling a waste heat utilization apparatus according to claim 22, wherein the rotational speed of the pump means (22) is estimated from the rotational speed of the internal combustion engine (10). The pump means (22) is driven by the power of an electric motor,
23. The method for controlling a waste heat utilization apparatus according to claim 22, wherein the rotational speed of the pump means (22) is estimated from a control value at the time of the electric motor operation control. The electric motor is one whose operation output is duty controlled,
The method for controlling a waste heat utilization apparatus according to claim 24, wherein the control value is a voltage duty ratio of the electric motor. The electric motor is an inverter whose operation output is controlled by an inverter,
The method for controlling a waste heat utilization apparatus according to claim 24, wherein the control value is a frequency of an inverter voltage of the electric motor. The cooling medium is outside air;
The waste heat utilization apparatus according to claim 18, wherein the condensing capacity is grasped by the temperature of the outside air, and the operating rotational speed of the generator (321) is increased as the temperature of the outside air is lower. Control method. The cooling medium is outside air;
The waste heat utilization apparatus according to claim 18, wherein the condensing capacity is grasped by the flow rate of the outside air, and the operating rotational speed of the generator (321) is increased as the flow rate of the outside air is increased. Control method.   29. The method for controlling a waste heat utilization apparatus according to claim 28, wherein a flow rate of the outside air is estimated from a wind speed of the outside air. Mounted in a vehicle, the outside air is introduced into the condenser (220) by vehicle speed wind.
The waste heat utilization apparatus control method according to claim 28, wherein the flow rate of the outside air is estimated from a vehicle speed of the vehicle.   30. The method according to claim 29, wherein the vehicle includes a general passenger car, a hybrid car, and a truck. As the refrigerant pressure, at least one of a high pressure side pressure of the Rankine cycle (300) and a low pressure side pressure of the Rankine cycle (300) is used,
The method of controlling a waste heat utilization apparatus according to claim 18, wherein the operating rotational speed of the generator (321) is increased as at least one of the high-pressure side pressure and the low-pressure side pressure is lower. When setting the operating rotational speed of the generator (321), two or more values of the cooling water temperature, the cooling water flow rate, the outside air temperature, the outside air flow rate, and the refrigerant pressure value are selected. Value is used,
The operating rotational speed of the generator (321) is determined using a minimum value among the operating rotational speeds calculated from the two or more values. The control method of the waste heat utilization apparatus of Claim 28 and Claim 32. A refrigeration cycle (200) having a compressor (210), an air conditioner condenser (220A), an expansion valve (240), and an evaporator (250);
The waste heat utilization apparatus control method according to any one of claims 18 to 33, wherein the condenser (220) and the air conditioner condenser (220A) are shared.

Images