JP2012193671A - Waste heat recovery apparatus - Google Patents

Abstract

Provided is a waste heat recovery apparatus capable of easily and quickly determining a failure of vaporization of a working fluid in a superheater and executing an appropriate improvement process corresponding to the determined failure.
A waste heat recovery system (1) includes first failure determination means for determining a failure of vaporization of a working fluid in a superheater (8) based on a recovered heat amount and surface heat radiation amount of the system and an exhaust gas heat amount of an engine (50). The first improvement processing execution means for executing the processing for improving the failure of vaporization of the working fluid in the superheater 8 and the first improvement processing execution means executed when the first determination means is determined to be defective. Second failure determination means for determining failure of vaporization of the working fluid in the superheater 8 based on the recovered heat amount and surface heat release amount of the later system and the exhaust gas heat amount of the engine 50.
[Selection] Figure 5

Description

  The present invention relates to a waste heat recovery apparatus.

  2. Description of the Related Art Conventionally, a waste heat recovery apparatus that recovers waste heat accompanying operation of an internal combustion engine via a working fluid is known. As such a waste heat recovery apparatus, a configuration including an evaporator (superheater) that vaporizes the working fluid of the waste heat recovery apparatus by the heat of exhaust gas discharged from the internal combustion engine is widely adopted.

  For example, Patent Document 1 discloses a technique for improving the recovery efficiency of engine waste heat by exchanging heat between the working fluid vaporized by the superheater and the cooling water of the internal combustion engine.

  Further, Patent Documents 2 and 3 disclose other technologies that are considered to be related to the present invention.

JP 2010-156315 A JP 2009-174379 A JP-A-2005-117836

  In such a waste heat recovery device, when a failure occurs due to, for example, “freezing of the working fluid in the device”, “rising of the boiling point of the working fluid accompanying an increase in the internal pressure of the superheater”, “failure of the superheater”, etc. The working fluid cannot evaporate properly, and the waste heat recovery efficiency decreases. Therefore, it is required to easily and quickly determine the failure of vaporization of the working fluid in the superheater of the waste heat recovery apparatus. In addition, it is required to identify the cause of the vaporization failure of the working fluid in the superheater so that appropriate improvement processing can be performed for the failure that has occurred.

  This invention is made | formed in view of this point, and provides the waste heat recovery apparatus which can specify the cause of a defect, determining the defect of the vaporization of the working fluid in a superheater simply and rapidly. For the purpose.

In order to achieve the above object, the present invention provides a waste heat recovery apparatus having a superheater that exchanges heat with waste heat of an internal combustion engine to vaporize the working fluid, wherein the working fluid is vaporized in the superheater. A first defect determination unit that determines a defect; and a first improvement process execution unit that executes a process of improving a vaporization defect of the working fluid in the superheater when the first determination unit determines a defect; And second failure determination means for determining a failure of vaporization of the working fluid in the superheater after the first improvement process execution means has executed the process.
With the above configuration, it is possible to identify the cause of the failure while easily and quickly determining the failure of vaporization of the working fluid in the superheater.

In particular, the waste heat recovery apparatus of the present invention may be configured such that the first improvement processing execution means is one of heating the working fluid and reducing the pressure inside the superheater. it can.
With the above configuration, it is determined whether the cause of the vaporization failure of the working fluid in the superheater is the freezing of the working fluid in the system or the boiling point of the working fluid as the internal pressure of the superheater increases be able to.

Further, in the waste heat recovery apparatus of the present invention, the first failure determination means and the second failure determination means are based on the recovered heat amount and surface heat radiation amount of the waste heat recovery device and the exhaust gas heat amount of the internal combustion engine. It can be set as the structure which determines the defect of vaporization of the working fluid in the said superheater.
With the above configuration, it is possible to easily and quickly determine whether the working fluid is vaporized in the superheater without providing a new sensor or the like.

The waste heat recovery apparatus according to the present invention is a process for improving a vaporization failure of the working fluid in the superheater when the second determination unit determines that the second determination unit is defective, and executing the first improvement process. Second improvement process execution means for executing processing different from the means, and third failure determination means for determining failure of vaporization of the working fluid in the superheater after the second improvement process execution means has executed the process. It can be set as the structure provided with these.
With the above configuration, the cause of the failure can be specified in more detail while easily and quickly determining the failure of vaporization of the working fluid in the superheater.

Furthermore, the waste heat recovery apparatus of the present invention may be configured such that the second improvement processing execution means is one of heating the working fluid and reducing the pressure inside the superheater. it can.
According to the above configuration, the cause of the vaporization failure of the working fluid in the superheater is the freezing of the working fluid in the system, the boiling point of the working fluid as the internal pressure of the superheater increases, or the superheater Can be identified.

Further, in the waste heat recovery apparatus of the present invention, the third failure determination unit is configured to reduce the amount of working fluid in the superheater based on the recovered heat amount and surface heat release amount of the waste heat recovery device and the exhaust gas heat amount of the internal combustion engine. It can be set as the structure which determines the defect of vaporization.
With the above configuration, it is possible to easily and quickly determine whether the working fluid is vaporized in the superheater without providing a new sensor or the like.

The waste heat recovery apparatus according to the present invention includes a notification unit that notifies the user of the internal combustion engine of the failure of the superheater when the third failure determination unit determines that the failure has occurred. it can.
With the above configuration, when it is specified that the cause of the vaporization failure of the working fluid in the superheater is a failure of the superheater, the fact is notified to the user of the internal combustion engine to prompt the repair of the superheater. it can.

  According to the waste heat recovery apparatus of the present invention, the cause of the failure can be specified while determining the failure of vaporization of the working fluid in the superheater easily and quickly.

It is the figure which showed one structural example of the waste heat recovery system of an Example. It is the figure which showed schematic structure of the superheater. It is the figure which showed schematic structure of the connection part of a liquid reservoir tank and a working fluid circulation flow path. The determination method of the defect of the vaporization of the refrigerant | coolant in the superheater of the waste heat recovery system of an Example is shown. It is a flowchart which shows an example of a process of ECU.

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

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a waste heat recovery system 1 provided with a waste heat recovery apparatus of the present invention.

  The waste heat recovery system 1 shown in FIG. 1 is a vapor loop system that recovers and liquefies the heat of the vaporized working fluid after the working fluid that is liquid at normal temperature is vaporized by exchanging heat with the waste heat of the engine 50. Is forming. The waste heat recovery system 1 includes a superheater 8 assembled in the exhaust passage 501 of the engine 50, and includes a heater core 10 that communicates with the superheater 8 through the working fluid circulation channel 3. Further, the waste heat recovery system 1 includes an ECU (Electronic Control Unit) 30 that comprehensively controls the operation of the system. The waste heat recovery system 1 includes a liquid reservoir tank 14, a first control valve 143, and a second control valve 144 in the middle of the working fluid circulation channel 3.

The engine 50 is a multi-cylinder engine mounted on a vehicle, and each cylinder includes a piston that constitutes a combustion chamber. The piston of each combustion chamber is connected to a crankshaft as an output shaft member via a connecting rod.
The working fluid circulation channel 3 is connected to the engine 50. The other side of the working fluid circulation channel 3 is connected to the superheater 8, thereby forming a cycle in which the working fluid circulates between the engine 50 and the superheater 8. The working fluid is vaporized by exchanging heat with the exhaust gas flowing through the exhaust passage 501 of the engine 50 while circulating through the superheater 8. The vaporized working fluid reaches the engine 50 via the working fluid circulation passage 3 and locally warms a part of the engine 50. The working fluid cooled by heat exchange with the engine 50 returns to a liquid and is returned to the superheater 8 via the working fluid circulation passage 3. That is, the engine 50 functions as a condenser for the working fluid. The engine 50 adjusts the output to change the heat quantity of the exhaust gas, thereby adjusting the efficiency of vaporization in the superheater 8 and adjusting the pressure of the steam of the working fluid circulating in the system path.
The engine 50 is a configuration example of the second improvement processing execution unit of the present invention.

  The superheater 8 is a steam generator installed in the exhaust passage 501 on the downstream side of the exhaust purification catalyst of the engine 50. FIG. 2 is a diagram showing a schematic configuration of the superheater 8. The superheater 8 has a configuration in which the working fluid circulates in the inside thereof, and heat exchange is performed between the exhaust gas passing through the superheater 8 and the working fluid. Although water is used as the working fluid in this embodiment, the same LLC (Long Life Coolant) as the engine cooling water may be used, or other fluids may be used. The working fluid circulation channel 3 is connected to the superheater 8. The other side of the working fluid circulation channel 3 is connected to the engine 50 and the heater core 10, thereby forming a cycle in which the working fluid circulates between the superheater 8, the engine 50 and the heater core 10.

  The heater core 10 heats air (air conditioned air) introduced into the vehicle of the vehicle on which the engine 50 is mounted by the heat of the working fluid vaporized through the superheater 8. That is, the heater core 10 is configured to recover energy by exchanging heat with the vaporized working fluid of the conditioned air blown by the blower. The working fluid heat-exchanged with the conditioned air in the heater core 10 returns to a liquid and is returned to the superheater 8 via the working fluid circulation passage 3. That is, the heater core 10 functions as a condenser for the working fluid. A temperature sensor 101 and an air volume sensor 102 are installed in the heater core 10, and the temperature of the heater core 10 and the air volume of the blower are detected and transmitted to the ECU 30. The ECU 30 recognizes the recovered heat quantity of the waste heat recovery system 1 from the received detection results of the temperature sensor 101 and the air volume sensor 102.

The liquid reservoir tank 14 is provided in the middle of the working fluid circulation passage 3 through which the working fluid from the superheater 8 toward the engine 50 flows. The liquid reservoir tank 14 has a configuration in which the vaporized working fluid flowing through the working fluid circulation passage 3 is taken inside, and the taken working fluid is condensed, liquefied, and stored.
The liquid tank 14 is an example of the configuration of the second improvement processing execution means (or first improvement processing execution means) of the present invention.

  A connecting portion between the liquid storage tank 14 and the working fluid circulation passage 3 has a first connecting portion 141 and a second connecting portion 142, and a first control valve 143 and a second control valve 144 are provided respectively. It has been. FIG. 3 is a diagram showing a schematic configuration of a connection portion between the liquid reservoir tank 14 and the working fluid circulation passage 3. The first connection part 141 is provided above the second connection part 142. The first control valve 143 and the second control valve 144 are urged in a direction to close the first connection portion 141 and the second connection portion 142, respectively, by an urging force of an elastic member (for example, a helical spring). Further, the urging force of the first control valve 143 in the valve closing direction is set larger than the urging force of the second control valve 144 in the valve closing direction.

The opening / closing behavior of the first control valve 143 and the second control valve 144 will be described. When the pressure of the vapor of the working fluid flowing through the working fluid circulation channel 3 rises and exceeds the biasing force of the elastic member, the first control valve 143 and the second control valve 144 become the first connection portion 141 and the second connection portion 142. Move in the direction to release. As a result, the working fluid circulation channel 3 and the liquid storage tank 14 communicate with each other, and the vapor flowing through the working fluid circulation channel 3 flows into the liquid storage tank 14 (see FIG. 3A). The vapor flowing into the liquid tank 14 is condensed and liquefied and stored in the liquid tank 14. Then, when the pressure of the steam flowing through the working fluid circulation channel 3 decreases and falls below the urging force of the elastic member of the first control valve 143, the first control valve 143 moves in a direction to close the first connection portion 141. (See FIG. 3B). Then, the liquefied working fluid stored in the liquid storage tank 14 flows out to the working fluid circulation passage 3 through the second connection portion 142. When the pressure of the steam flowing through the working fluid circulation channel 3 further decreases and falls below a predetermined pressure, the second control valve 144 moves in a direction to close the second connection part 142 (see FIG. 3C). The working fluid outflow to the working fluid circulation passage 3 stops. By such opening and closing behavior of the control valve, the working fluid circulating through the waste heat recovery system 1 is adjusted to a predetermined amount, whereby the internal pressure of the working fluid circulation channel 3 is reduced to a predetermined pressure or less. In this case, the amount of the working fluid circulating in the system path can be arbitrarily adjusted by adjusting the biasing force of the elastic member of the first control valve 143.
The first control valve 143 and the second control valve 144 are a configuration example of the second improvement processing execution means (or first improvement processing execution means) of the present invention.

A hot wire heater 19 is provided in the working fluid circulation passage 3 through which the working fluid circulates. Specifically, the hot wire heater 19 is provided in the working fluid circulation passage 3 on the side (liquid line) where the working fluid liquefied by heat exchange in the engine 50 and the heater core 10 returns to the superheater 8. The hot wire heater 19 is wound around the outer surface of the liquid line of the working fluid circulation channel 3, generates heat based on a command from the ECU 30 to be described later, and transfers the working fluid existing in the working fluid circulation channel 3 from the outside. Heat. In this case, the hot wire heater 19 is not limited to the configuration wound around the outer surface of the liquid line of the working fluid circulation channel 3, but is configured to be attached to the outer surface of the liquid line or the liquid line of the working fluid circulation channel 3. The structure provided in an internal side may be sufficient. Further, the position where the heat ray heater 19 is installed is not limited to the above-described part, and can be provided at an arbitrary position in the system path where heat dissipation is large.
The hot wire heater 19 is an example of the configuration of the first improvement processing execution means and the second improvement processing execution means of the present invention.

  The waste heat recovery system 1 includes an outside air temperature sensor 21. The outside air temperature sensor 21 detects the temperature outside the system and transmits the detection result to the ECU 30 described later. In addition, the waste heat recovery system 1 includes an indoor temperature sensor 22. The room temperature sensor 22 detects the temperature in the room of the vehicle on which the system is mounted, and transmits the detection result to the ECU 30 described later. The ECU 30 recognizes the temperature outside the system and the room temperature from the detection results of the received outside air temperature sensor 21 and indoor temperature sensor 22.

  In addition to the above, the waste heat recovery system 1 includes an ECU 30 that comprehensively controls the operation of the system. The ECU 30 includes a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that stores data, and an NVRAM (Non Volatile RAM). It is a computer. The ECU 30 of this embodiment also serves as an ECU that controls the operation of the engine 50 in an integrated manner, but may be provided separately.

  The ECU 30 determines a failure of vaporization of the working fluid in the superheater 8 of the waste heat recovery system 1, and executes a defect improvement process based on the determination result. And ECU30 performs control which specifies the cause of a failure by determining the failure of vaporization of the working fluid in superheater 8 after execution of improvement processing. Below, control of the waste-heat recovery system 1 which ECU30 performs is demonstrated.

  First, the ECU 30 calculates the amount of heat recovered and the surface heat radiation of the waste heat recovery system 1 and the amount of exhaust gas heat of the engine 50 during operation of the engine 50 (when the ignition switch is ON). Specifically, the ECU 30 recovers the amount of heat recovered by the waste heat recovery system 1 from the temperature of the heater core 10 detected by the temperature sensor 101, the air volume of the blower detected by the air volume sensor 102, and the indoor temperature of the vehicle detected by the indoor temperature sensor 22. Is calculated. In this case, the correlation between the temperature of the heater core 10, the air flow rate of the blower and the room temperature and the recovered heat amount of the system is confirmed in advance by a bench test or the like, and a map is created and stored in the ROM or the like of the ECU 30. The amount of heat recovered by the system can be calculated easily and quickly. Further, the ECU 30 calculates the surface heat radiation amount of the waste heat recovery system 1 from the amount of heat recovered by the waste heat recovery system 1 and the temperature outside the system detected by the outside air temperature sensor 21. Then, the ECU 30 calculates the exhaust gas heat amount of the engine 50 from the output (rotation speed, load) of the engine 50 recognized from the detection result of the crank angle sensor or the like of the engine 50. The surface heat radiation amount of the system and the exhaust gas heat amount of the engine 50 can also be calculated easily and quickly by creating a map in advance by a bench test or the like.

（Ｑ_ｋａｉ：システム回収熱量，Ｑ_ｓ：システム表面放熱量，Ｑ_ｅｘ：エンジン排ガス熱量）
ＥＣＵ３０は、上記（１）から算出したη_ｂ値と、廃熱回収システム１の過熱器８における作動流体の蒸気化が正常に行われているときに上記（１）式から算出した正常値（η_ａ値）との差分（｜η_ａ−η_ｂ｜＝θ）を算出する（図４参照）。この場合、正常値η_ａ値は、予め台上試験等で求めた値をＥＣＵ３０のＲＯＭ等に記憶させておくことができる。そして、ＥＣＵ３０は、求めた差分θが所定のしきい値未満である場合、過熱器８における作動流体の蒸気化が正常に行われている（すなわち不良でない）と判定し、制御の処理を終了する。一方、ＥＣＵ３０は、求めた差分θが所定のしきい値以上である場合、過熱器８における作動流体の蒸気化が正常に行われていない（すなわち不良である）と判定する。ここで、不良判定のための所定のしきい値は、安全率やその他の影響を加味した任意の値を適用することができるが、ゼロ（０）値を適用してもよい。 Subsequently, the ECU 30 executes control (first failure determination) for determining failure of vaporization of the working fluid in the superheater 8 based on the calculated recovered heat amount, surface heat release amount, and exhaust gas heat amount. Specifically, the ECU 30 calculates the current value (η _b value) of the waste heat recovery system 1 based on the following equation (1), for example.
[Calculation formula for the current value of waste heat recovery system]

(Q _kai : system recovery heat, Q _s : system surface heat dissipation, Q _ex : engine exhaust gas heat)
The ECU 30 calculates the η _b value calculated from the above (1) and the normal value calculated from the above formula (1) when the working fluid is normally vaporized in the superheater 8 of the waste heat recovery system 1 ( The difference (| η _a −η _b | = θ) with respect to (η _a value) is calculated (see FIG. 4). In this case, as the normal value ηa value, _a value obtained in advance by a bench test or the like can be stored in the ROM of the ECU 30 or the like. When the obtained difference θ is less than the predetermined threshold value, the ECU 30 determines that the working fluid is vaporized normally (that is, not defective) in the superheater 8 and ends the control process. To do. On the other hand, when the obtained difference θ is equal to or greater than a predetermined threshold value, the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, defective). Here, as the predetermined threshold value for defect determination, an arbitrary value in consideration of the safety factor and other influences can be applied, but a zero (0) value may be applied.

  ECU30 performs the process (1st improvement process) for improving a defect, when it determines with the vaporization of the working fluid in the superheater 8 being defective in 1st defect determination. Specifically, the ECU 30 instructs the heat-wire heater 19 to generate heat, and heats the working fluid in the system path, thereby executing control for improving the defect based on “freezing of the working fluid in the system path”. . The ECU 30 determines that “freezing of the working fluid in the system path” has been improved when a predetermined time has elapsed since the heat generation of the heat ray heater 19 is turned on, and commands the heat ray heater 19 to turn off the heat generation.

ECU30 performs control (2nd defect determination) which determines the defect of the vaporization of the working fluid in the superheater 8 again after performing the 1st improvement process. Specifically, the ECU 30 calculates the recovered heat amount and the surface heat radiation amount of the waste heat recovery system 1 and the exhaust gas heat amount of the engine 50 after executing the first improvement process. Then, the ECU 30 calculates the current value (η _b value) of the waste heat recovery system 1 from the above equation (1), and the difference (| η _a −η _b | = from the normal value (η _a value) obtained in advance. θ) is calculated (see FIG. 4). When the obtained difference θ is less than a predetermined threshold value, the ECU 30 determines that the working fluid is normally vaporized in the superheater 8 (that is, it is not defective), and the cause of the failure is “system path”. It is determined that the working fluid is frozen, and the control process is terminated. On the other hand, when the obtained difference θ is equal to or greater than a predetermined threshold value, the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, defective).

  When the ECU 30 determines that the vaporization of the working fluid in the superheater 8 is defective in the second defect determination, the ECU 30 is a process for improving the defect and is different from the first improvement process (second improvement). Process). Specifically, the ECU 30 commands the engine 50 to increase the output, commands the heat ray heater 19 to generate heat, and reduces the pressure in the system path (inside the superheater 8), thereby The control which improves the defect based on "the boiling point rise of the working fluid accompanying the rise in pressure" is performed.

An example of control for reducing the pressure inside the superheater 8 in this embodiment will be described. First, the ECU 30 commands the engine 50 to improve the output, and increases the exhaust gas heat amount of the engine 50 to promote the vaporization of the working fluid in the superheater 8. At the same time, the ECU 30 instructs the heater core 10 to generate heat, and heats and vaporizes the working fluid flowing through the liquid line of the working fluid circulation passage 3. This increases the pressure of the steam in the system path. When the pressure of the steam in the system path increases, the first control valve 143 and the second control valve 144 move in a direction to open the first connection part 141 and the second connection part 142, and flow through the working fluid circulation channel 3. Steam and gas to flow into the liquid storage tank 14 (see FIG. 3A). Subsequently, the ECU 30 instructs the heater core 10 to stop the heat generation while instructing to stop improving the output of the engine 50, thereby reducing the pressure of the steam in the system path. When the pressure of the steam in the system path decreases, the first control valve 143 moves in a direction to close the first connection portion 141 (see FIG. 3B), and the working fluid stored in the liquid storage tank 14 is moved. It flows out to the working fluid circulation channel 3. When the pressure of the steam in the system path further decreases, the second control valve 144 moves in a direction to close the second connection part 142 (see FIG. 3C), and the working fluid flows into the working fluid circulation passage 3. The outflow stops. As a result, the working fluid circulating in the system path is adjusted to a predetermined amount, so that the pressure in the system path is reduced to a predetermined pressure or less. That is, the output of the engine 50 is improved to increase the amount of exhaust gas heat, or the heating fluid is heated to vaporize the heating fluid circulating through the working fluid circulation passage 3 by generating heat from the heat ray heater 19. The pressure can be reduced.
In this case, the ECU 30 may command one of the output improvement to the engine 50 and the heat generation to the heater core 10 in order to reduce the pressure inside the superheater 8. Further, the control for reducing the pressure inside the superheater 8 is not limited to the above. For example, if it is the structure provided with the pump which decompresses the inside of a system path | route, you may reduce the pressure inside the superheater 8 by turning ON the drive of a pump.

After executing the second improvement process, the ECU 30 again executes control (third defect determination) for determining a failure of vaporization of the working fluid in the superheater 8. That is, the ECU 30 determines the current value (η _b value) of the waste heat recovery system 1 after executing the second improvement process and the normal value (η _a value) obtained in advance, as in the first and second defect determinations described above. ) (| Η _a −η _b | = θ) is calculated (see FIG. 4). When the obtained difference θ is less than the predetermined threshold value, the ECU 30 determines that the working fluid is vaporized normally in the superheater 8 (that is, not defective), and the cause of the defect is “ The control processing is terminated by specifying that the boiling point of the working fluid has increased as the internal pressure of the superheater 8 increases. On the other hand, when the obtained difference θ is equal to or greater than a predetermined threshold value, the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, defective).

When the ECU 30 determines in the third failure determination that the vaporization of the working fluid in the superheater 8 is defective, the ECU 30 identifies the cause of the failure as “failure of the superheater 8”. Subsequently, the ECU 30 lights up an abnormality indicator light (hereinafter, abbreviated as MIL) corresponding to the “failure of the superheater 8” to the user of the vehicle on which the engine 50 is mounted. “Failure” is notified, and the control process is terminated. In this case, the notifying means is not limited to the lighting of the MIL, and the failure may be notified to the user by other methods such as voice.
The ECU 30 repeats the above control while the ignition switch of the vehicle is ON.

  In a waste heat recovery device system provided in an internal combustion engine, the energy recovery rate is increased by heat-exchanging waste heat of exhaust gas and working fluid in a superheater for vaporization. For this reason, if an abnormal defect in the vaporization of the working fluid in the superheater occurs, the recovery efficiency of the engine waste heat will be greatly reduced. It is demanded to execute an improvement process. However, the cause of the failure of vaporization of the working fluid in the superheater is, for example, “freezing of the working fluid in the system”, “boiling point rise of working fluid due to increase in internal pressure of superheater”, “superheater failure”, etc. There is. Therefore, in order to execute an appropriate improvement process for an abnormal failure, it is required to identify the cause of the failure of vaporization of the working fluid in the superheater.

  Therefore, the waste heat recovery system 1 according to the present embodiment executes the first to third defect determination control based on the recovered heat amount and surface heat radiation amount of the waste heat recovery system 1 and the exhaust gas heat amount of the engine 50, whereby the superheater 8 It is possible to easily and quickly determine whether or not the working fluid is vaporized. And by performing control of 1st-3rd defect determination and 1st-2nd improvement process, the cause of the defect of the vaporization of the working fluid in the superheater 8 is "freezing of the working fluid in a system." , “Boiling point rise of working fluid accompanying increase in internal pressure of superheater” or “failure of superheater” can be specified.

  Further, the waste heat recovery system 1 of the present embodiment is provided with a new sensor or the like for the recovered heat amount, the surface heat radiation amount, and the exhaust gas heat amount of the engine 50 that are used for determining the failure of vaporization of the working fluid in the superheater 8. It can be obtained from existing equipment. Therefore, improvement in system cost can be suppressed.

In the present embodiment, the process for improving the defect based on the “freezing of the working fluid in the system path”, which is more frequently generated, is defined as the first improvement process, and the “boiling point of the working fluid accompanying the increase in the internal pressure of the superheater 8”. Although the process for improving the defect based on “rising” is the second improvement process, it is not limited to this. That is, according to the operating environment of the internal combustion engine or the like, a process for improving a defect based on “an increase in the boiling point of the working fluid accompanying an increase in the internal pressure of the superheater 8” is referred to as a first improvement process. The process for improving the defect based on “freezing” may be the second improvement process. Moreover, although the 1st-3rd defect determination was performed in a present Example, the structure which performs a 1st and 2nd defect determination may be sufficient. In this case, the “failure of the superheater 8” can be notified to the user after the second failure determination.
The ECU 30 is a configuration example of the first defect determination unit, the second defect determination unit, the third defect determination unit, and the notification unit according to the present invention.

  Subsequently, the operation of the waste heat recovery system 1 will be described along the control flow of the ECU 30. FIG. 5 is a flowchart illustrating an example of processing of the ECU 30. The waste heat recovery system 1 of the present embodiment performs the first to second improvement processes while performing the first to third defect determinations based on the recovered heat amount and the surface heat radiation amount of the waste heat recovery system 1 and the exhaust gas heat amount of the engine 50. By executing this, the control for identifying the cause of the failure of vaporization of the working fluid in the superheater 8 is executed.

  The control of the ECU 30 is started when the ignition switch is turned on and the engine 50 is started, and the following control process is repeated while the engine 50 is in operation. Further, the ECU 30 always receives the detection results of the temperature sensor 101, the air volume sensor 102, and the outside air temperature sensor 21 during the control process.

First, in step S1, the ECU 30 calculates a difference (| η _a −η) between _a current value (η _b value) of the waste heat recovery system 1 calculated from the above equation (1) and a normal value (η _a value) obtained in advance. _b | = θ) is calculated (see FIG. 4). After finishing the process of step S1, the ECU 30 proceeds to the next step S2.

  In step S2, the ECU 30 executes a first failure determination for determining whether or not the difference θ calculated in step S1 is equal to or greater than a predetermined threshold value. Since the predetermined threshold value has been described above, a detailed description thereof will be omitted. When the difference θ is not equal to or greater than the predetermined threshold value (less than the threshold value) (step S2 / NO), the ECU 30 is normally vaporizing the working fluid in the superheater 8 (that is, not defective). And the control process ends. When the difference θ is equal to or larger than the predetermined threshold value (step S2 / YES), the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, defective), and The process proceeds to step S3.

  In step S3, the ECU 30 instructs the heat ray heater 19 to generate heat, and heats the working fluid in the system path, thereby improving the defect based on “freezing of the working fluid in the system path” (first improvement). Process). After completing the process of step S3, the ECU 30 proceeds to the next step S4.

In step S4, the ECU 30 calculates the current value (η _b value) of the waste heat recovery system 1 after the execution of the first improvement process from the above equation (1), and calculates the normal value (η _a value) obtained in advance. The difference (| η _a −η _b | = θ) is calculated (see FIG. 4). After finishing the process of step S4, the ECU 30 proceeds to the next step S5.

  In step S5, the ECU 30 executes second defect determination for determining whether or not the difference θ calculated in step S4 is equal to or greater than a predetermined threshold value. When the difference θ is not greater than or equal to the predetermined threshold value (less than the threshold value) (step S5 / NO), the ECU 30 is normally vaporizing the working fluid in the superheater 8 (that is, not defective). It is determined that the cause of the failure is “freezing of the working fluid in the system path”, and the control process is terminated. When the difference θ is equal to or larger than the predetermined threshold (step S5 / YES), the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, is defective), and then The process proceeds to step S6.

  In step S <b> 6, the ECU 30 instructs the engine 50 and the heat wire heater 19 to reduce the pressure inside the superheater 8, thereby causing a failure based on “an increase in the boiling point of the working fluid accompanying an increase in the internal pressure of the superheater 8”. The control for improving (second improvement process) is executed. In addition, since the control content of the 2nd improvement process was mentioned above, the detailed description is abbreviate | omitted. After finishing the process of step S6, the ECU 30 proceeds to the next step S7.

In step S7, the ECU 30 calculates the current value (η _b value) of the waste heat recovery system 1 after the execution of the second improvement process from the above equation (1), and calculates the normal value (η _a value) obtained in advance. The difference (| η _a −η _b | = θ) is calculated (see FIG. 4). After finishing the process of step S7, the ECU 30 proceeds to the next step S8.

  In step S8, the ECU 30 executes third defect determination for determining whether or not the difference θ calculated in step S7 is equal to or greater than a predetermined threshold value. When the difference θ is not equal to or greater than the predetermined threshold value (less than the threshold value) (step S8 / NO), the ECU 30 is normally vaporizing the working fluid in the superheater 8 (that is, not defective). It is determined that the cause of the defect is “an increase in the boiling point of the working fluid accompanying an increase in the internal pressure of the superheater 8”, and the control process is terminated. When the difference θ is equal to or greater than the predetermined threshold value (step S8 / YES), the ECU 30 determines that the working fluid is not normally vaporized in the superheater 8 (that is, defective), and then The process proceeds to step S9.

  In step S9, the ECU 30 specifies that the cause of the failure of vaporization of the working fluid in the superheater 8 is “failure of the superheater 8”. Subsequently, the ECU 30 lights up the MIL corresponding to “failure of the superheater 8”, and notifies the user of the vehicle on which the engine 50 is mounted “failure of the superheater 8”. When finishing the process of step S9, the ECU 30 ends the control process.

  By executing the above control, it is possible to easily and quickly determine whether the working fluid is vaporized in the superheater 8 of the waste heat recovery system 1. Further, the cause of the failure of vaporization of the working fluid in the superheater 8 is “freezing of the working fluid in the system”, “increase in boiling point of the working fluid accompanying an increase in the internal pressure of the superheater”, “failure of the superheater” Can be specified.

  As described above, the waste heat recovery system of the present embodiment determines whether the working fluid is vaporized poorly in the superheater based on the recovered heat amount and surface heat release amount of the waste heat recovery system and the exhaust gas heat amount of the engine. A first failure determination means; a first improvement process execution means for executing a process for improving a failure of vaporization of the working fluid in the superheater when the first determination means determines a failure; and a first improvement process execution means. Second failure determination means for determining failure of vaporization of the working fluid in the superheater based on the recovered heat amount and surface heat release amount of the waste heat recovery system after the processing is performed and the exhaust gas heat amount of the engine. Thus, it is possible to identify the cause of the failure while simply and quickly determining the failure of the working fluid vaporization in the superheater.

  Further, the waste heat recovery system of the present embodiment is a process for improving the vaporization of the working fluid in the superheater when the second determination unit determines that the second determination unit is defective, and the first improvement process execution unit. Is based on the second improvement processing execution means for executing different processes, the recovered heat amount and surface heat radiation amount of the waste heat recovery system after the second improvement processing execution means executes the processing, and the exhaust gas heat amount of the engine. By providing the third failure determination means for determining the failure of vaporization of the working fluid in the heater, the cause of the failure of vaporization of the working fluid in the superheater can be specified in more detail.

  The above embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to these, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

  For example, the present invention is a Rankine cycle (steam turbine cycle) system that replaces the heater core 10 of the present embodiment with a steam turbine having a turbine that can be rotated by steam, and converts thermal energy into electric energy or the like for recovery. Can also be applied.

  Further, instead of the mechanical first control valve 143 and the second control valve 144, an electronic control valve or a check valve that opens and closes based on a command from the ECU 30 is provided, so that the liquid reservoir tank 14 and the working fluid circulation passage 3 are provided. You may control opening and closing of the connection part. In this case, it is desirable to provide a water level sensor in the liquid storage tank 14 to control the opening / closing of the electronic control valve based on the amount of working fluid stored in the liquid storage tank 14.

DESCRIPTION OF SYMBOLS 1 Waste heat recovery system 3 Working fluid circulation flow path 8 Superheater 10 Heater core 14 Liquid reservoir tank (2nd improvement process execution means)
19 Heat wire heater (first improvement processing execution means, second improvement processing execution means)
21 outside air temperature sensor 22 indoor temperature sensor 30 ECU (first defect determination means, second defect determination means, third defect determination means, notification means)
50 engine (second improvement processing execution means)
101 Temperature Sensor 102 Air Flow Sensor 141 First Connection Unit (Second Improvement Processing Execution Unit)
142 2nd connection part (2nd improvement process execution means)
143 1st control valve (2nd improvement process execution means)
144 Second control valve (second improvement processing execution means)

Claims (7)

A waste heat recovery device having a superheater that exchanges heat with waste heat of an internal combustion engine to vaporize a working fluid,
First failure determination means for determining failure of vaporization of the working fluid in the superheater;
First improvement processing execution means for executing a process for improving the failure of vaporization of the working fluid in the superheater when the first determination means determines that the failure is;
Second failure determination means for determining failure of vaporization of the working fluid in the superheater after the first improvement processing execution means has executed processing;
A waste heat recovery apparatus comprising:   2. The waste heat recovery apparatus according to claim 1, wherein the first improvement processing execution unit is one of heating a working fluid and lowering a pressure inside the superheater.   The first failure determination unit and the second failure determination unit are configured to determine whether the working fluid is vaporized in the superheater based on the recovered heat amount and surface heat release amount of the waste heat recovery device and the exhaust gas heat amount of the internal combustion engine. The waste heat recovery apparatus according to claim 1 or 2, wherein When the second determination means determines a failure, a second process for improving the vaporization failure of the working fluid in the superheater and performing a process different from the first improvement process execution means. Improvement processing execution means;
4. The apparatus according to claim 1, further comprising: a third defect determination unit that determines a vaporization defect of the working fluid in the superheater after the second improvement process execution unit executes the process. The waste heat recovery apparatus according to item 1.   The waste heat recovery apparatus according to claim 4, wherein the second improvement processing execution means is any one of heating the working fluid and reducing the pressure inside the superheater.   The third failure determination means determines a failure of vaporization of the working fluid in the superheater based on the recovered heat amount and surface heat radiation amount of the waste heat recovery device and the exhaust gas heat amount of the internal combustion engine. The waste heat recovery apparatus according to claim 4 or 5.   7. The system according to claim 4, further comprising a notification unit configured to notify a user of the internal combustion engine of a failure of the superheater when the third failure determination unit determines that the failure has occurred. Waste heat recovery equipment.

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