JP2011149373A - Waste heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste heat recovery device to recover energy from the steam generated by the waste heat of engine, capable of recovering the energy efficiently in case the power recovery is resumed from the condition that power recovery can no more be conducted owing to a decrease of the steam amount generated. <P>SOLUTION: The waste heat recovery device 1 is equipped with an impulse turbine 7 to work when the steam generated by the waste heat of the engine 100 is introduced, an electromagnetic clutch 10 to make coupling and uncoupling of a power shaft 73 of the turbine 7 with/from its rotor 12, and pulleys 13 and a belt 14 to transmit the power from the turbine 7 to a crank shaft 32 when the rotor 12 is coupled with the crank shaft 32 and the clutch 10 is coupled with the power shaft 73 and the rotor 12. The waste heat recovery device 1 has an ECU 17 which works when the steam amount introduced to the turbine 7 decrease below the first prescribed amount A1, for uncoupling the power shaft 73 from the rotor 23 using the clutch 10 while introducing the steam to the turbine 7 is continued. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a waste heat recovery device that recovers engine waste heat using a Rankine cycle system.

  2. Description of the Related Art A waste heat recovery device that recovers waste heat generated by driving an internal combustion engine (engine) using a Rankine cycle is known. In such a waste heat recovery device, steam generated by the waste heat of the engine is introduced into the turbine to operate the turbine, and mechanical power and electrical energy are recovered. For example, Patent Document 1 discloses an improved version of such a waste heat recovery apparatus.

  The waste heat recovery system of Patent Document 1 includes a plurality of nozzles that inject superheated steam into an impulse turbine, and is configured to be able to switch the presence or absence of superheated steam injection at the plurality of nozzles according to the pressure of the superheated steam. . According to Patent Document 1, this waste heat recovery system obtains high energy recovery efficiency in a wide range of engine operating conditions in which the flow rate and pressure of superheated steam change.

JP 2009-103060 A

  However, in such a waste heat recovery device, the amount of steam generated by the waste heat of the engine is reduced and the power recovery in the turbine cannot be performed when the engine load and the rotational speed are reduced. Conceivable. Patent Document 1 does not assume a case where the amount of steam is thus reduced and power recovery cannot be performed. By the way, when it becomes impossible to recover the power in the turbine due to the state of the steam as described above, a configuration is assumed in which the steam is bypassed without being introduced into the turbine. However, when the steam is not introduced, the turbine is stopped, and when the amount of steam is increased and the turbine is operated again, the rotation speed at which the power can be recovered after the steam is introduced into the turbine is reached. It takes time to complete. Thus, by stopping the turbine, efficient energy recovery is prevented.

  Therefore, an object of the present invention is to efficiently recover energy when power recovery in a turbine is resumed from a state where power recovery cannot be performed due to a decrease in the amount of steam.

  The waste heat recovery apparatus of the present invention that solves such a problem is a waste heat recovery apparatus that constitutes a Rankine cycle and recovers engine waste heat, and an expander that operates by introducing steam generated by engine waste heat; An energy recovery means having a power input section that operates in connection with the power shaft of the expander; and a clutch that connects and releases the power shaft and the power input section, and is introduced into the expander. When the energy of the steam falls below a first predetermined value, the clutch is released while continuing to introduce the steam into the expander.

  By adopting such a configuration, even when the amount of steam introduced into the expander decreases and power cannot be recovered, the expander can be maintained in a driven state without being stopped. As a result, when the amount of steam increases and power recovery is resumed, the time required for the expander to recover power can be shortened, and energy can be recovered efficiently. The first predetermined amount is the minimum amount of steam that can be recovered by the expander.

  In such a waste heat recovery apparatus, when the energy of the steam introduced into the expander is lower than the first predetermined value, the power input section of the power input unit is changed according to the energy of the steam introduced into the expander. In consideration of one inertial drive period, the clutch can be engaged during the first inertial drive period.

  Even when it is determined that the energy of the steam introduced into the expander cannot recover the power, the expander continues to be driven by inertia, so that the power can be recovered for a certain period. With the above configuration, the energy of the steam is recovered as much as possible, so that the energy recovery efficiency can be improved.

  In such a waste heat recovery apparatus, when the energy of the steam introduced into the expander becomes equal to or less than a second predetermined value smaller than the first predetermined value, the bypass means for bypassing the expander with the steam It can be set as the structure provided with.

  When the energy of the steam decreases, the steam may condense in the expander. When the vapor condenses in the expander, the condensed liquid may become the friction of the expander operation and damage the turbine blades. With the above configuration, when the energy of the steam becomes the second predetermined value at which the steam may condense, introduction of the steam into the expander is suppressed. As a result, condensation of steam in the expander is prevented, so that the friction of the expander is reduced and at the same time damage to the turbine blades can be prevented.

  In such a waste heat recovery apparatus, when the energy of the steam introduced into the expander is equal to or less than the second predetermined value, the power input unit In consideration of the second inertial drive period, the introduction of steam into the expander can be continued for a predetermined time during the second inertial drive period.

  Even when the energy of the steam introduced into the expander decreases so that the condensation of the steam occurs, the steam does not immediately start condensing because the expander continues to be driven by inertia. Even during this period, by continuing to drive the expander, when the steam energy is recovered, it is possible to quickly move to power recovery and improve the energy recovery efficiency.

  In such a waste heat recovery apparatus, the energy of the steam introduced into the expander can be estimated based on the amount of steam generated by recovering the waste heat of the engine.

  This makes it possible to estimate steam energy that is difficult to measure easily. The amount of steam can be estimated from engine load, engine speed, engine temperature, and the like. In addition, pressure measuring means for measuring the pressure of the steam introduced into the expander is provided, and the clutch engagement or disengagement can be determined based on the measurement value of the pressure measuring means.

  By adopting such a configuration, even when the amount of steam introduced into the expander becomes a predetermined amount or less that makes it impossible to recover power, the steam is introduced into the expander to idle the expander. Can do. As a result, when the amount of steam increases and power recovery is resumed, the time until the expander becomes capable of recovering power can be shortened, and waste heat energy can be recovered efficiently.

It is explanatory drawing which showed schematic structure of the waste heat recovery apparatus. It is explanatory drawing which showed schematic structure of a turbine and an electromagnetic clutch. It is the flow of control about the switching of the electromagnetic clutch of Example 1, and a three-way valve. It is explanatory drawing which showed an example of the map of the vapor | steam amount computed based on the engine speed and the engine load. It is the flow of control about the switching of the electromagnetic clutch of Example 2, and a three-way valve.

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

  Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a waste heat recovery apparatus 1 of the present embodiment. The waste heat recovery apparatus 1 is incorporated in the engine 100.

  The engine 100 includes an engine body 2, and the engine body 2 includes a cylinder head 21 and a cylinder block 22. The piston 3 is slidably disposed in the cylinder block 22. The piston 3 is connected to the crankshaft 32 by a connecting rod 31. Further, water jackets 41 and 42 through which the refrigerant passes are formed inside the cylinder head 21 and the cylinder block 22.

  The waste heat recovery apparatus 1 includes a refrigerant passage 5 through which refrigerant flows, a superheater 6, an impulse turbine 7, a condenser 8, and a water pump 9. The refrigerant passage 5 connects the pipe 51 connecting the water jacket 41 formed in the cylinder head 21 and the superheater 6, the pipe 52 connecting the superheater 6 and the impulse turbine 7, and the impulse turbine 7 and the condenser 8. The pipe 53, the pipe 54 connecting the condenser 8 and the water pump 9, the water pump 9, and the pipe 55 connecting the water jacket 42 formed on the cylinder block 22 are configured. That is, the refrigerant passage 5 forms a loop-shaped circulation passage that connects the water jacket 41 on the cylinder head 21 side and the water jacket 42 on the cylinder block 22 side. Then, on the refrigerant passage 5, the superheater 6, the impulse turbine 7, the condenser 8, and the water pump 9 are arranged in this order from the cylinder head 21 side to constitute the waste heat recovery apparatus 1.

  The refrigerant collects heat from the cylinder head 21 and the cylinder block 22 that are overheated by the operation of the engine 100 to cool the cylinder head 21 and the cylinder block 22 and evaporates into vapor. Evaporated steam collects at the upper part of the water jacket 41 formed in the cylinder head 21 and flows out to the pipe 51.

  The steam generated in the engine body 2 passes through the pipe 51 and flows into the superheater 6. The superheater 6 takes in the exhaust gas discharged after the combustion of the engine body 2 and exchanges heat between the steam and the exhaust gas. Thereby, the steam is superheated by the heat of the exhaust gas. The steam heated to a high temperature by the exhaust gas in this way passes through the pipe 52 and is introduced into the impulse turbine 7.

  The impulse turbine 7 is an expander that takes out steam energy and converts it into mechanical energy when high-temperature steam introduced therein expands. FIG. 2 is an explanatory diagram showing a schematic configuration of the impulse turbine 7 and the electromagnetic clutch 10. As shown in FIG. 2, the impulse turbine 7 includes an inlet 71 through which steam is introduced, an outlet 72 through which steam is led out, a power shaft 73, and a turbine wheel 74 coupled to the power shaft 73. The electromagnetic clutch 10 includes a coil 11 and a rotor 12 corresponding to a power input unit. In the electromagnetic clutch 10, when the coil 11 is energized, the electromagnetic particles enclosed between the power shaft 73 and the rotor 12 are coupled, and the power shaft 73 and the rotor 12 are engaged. Further, the rotor 12 is coupled to the pulley 13. The pulley 13 is connected to a crank pulley 33 coupled to the crankshaft 32 shown in FIG. Therefore, the electromagnetic clutch 10 connects the power shaft 73 of the impulse turbine 7 and the crankshaft 32 when the coil 11 is energized. In this case, the power shaft 73 of the impulse turbine 7 and the crankshaft 32 are interlocked, and power is transmitted from the impulse turbine 7 to the crankshaft 32. In the state where the power shaft 73 of the impulse turbine 7 and the crankshaft 32 are connected, when the steam flowing into the impulse turbine 7 exceeds a certain amount, the energy of the waste heat recovered by the steam assists the rotation of the crankshaft 32. Can be recovered as auxiliary power. On the other hand, when the energization to the coil 11 is stopped, the electromagnetic clutch 10 releases the connection between the power shaft 73 and the crankshaft 32 to the impulse turbine 7. As a result, the rotation of the impulse turbine 7 is not transmitted to the crankshaft 32, and the impulse turbine 7 idles. The steam after expanding in the impulse turbine 7 is led out to the pipe 53 from the outlet 72.

  Steam derived from the impulse turbine 7 flows into the condenser 8 through the pipe 53. The condenser 8 takes in air and exchanges heat with the inflowing steam. Thereby, the vapor | steam which flowed into the capacitor | condenser 8 is cooled and condensed, and changes to a liquid phase refrigerant | coolant. The refrigerant that has become a liquid phase in the condenser 8 is sucked and pumped by the water pump 9, passes through the pipes 54 and 55, and is supplied to the water jacket 42 formed in the cylinder block 22. As described above, the waste heat recovery apparatus 1 includes energy recovery means for recovering waste heat energy using a refrigerant as a working fluid, an engine body 2 as a steam generation source, and an impulse turbine 7 as an expander, thereby forming a Rankine cycle system. is doing.

  Further, the three-way valve 15 is incorporated in the pipe 52. The openings 151 and 152 of the three-way valve 15 are provided toward the upstream side and the downstream side of the pipe 52, and one end of the bypass passage 16 is connected to the opening 153. The other end of the bypass passage 16 is connected to the pipe 53 on the downstream side of the impulse turbine 7. The three-way valve 15 connects the opening 151 and the opening 152, the steam from the superheater 6 to the impulse turbine 7, and the steam from the superheater 6 that connects the opening 151 and the opening 153. Is switched to the passage for sending the to the bypass passage 16.

  Further, the waste heat recovery apparatus 1 includes an ECU (Electronic Control Unit) 17. The energization of the coil 11 is controlled by the ECU 17. That is, the ECU 17 controls the connection and release state of the power shaft 73 of the impulse turbine 7 and the crankshaft 32 by the electromagnetic clutch 10. The three-way valve 15 and the ECU 17 are electrically connected, and the ECU 17 controls the switching of the passage of the three-way valve 15.

  Next, switching control of the electromagnetic clutch 10 and the three-way valve 15 by the ECU 17 will be described. In this control, the ECU 17 opens the electromagnetic clutch 10 while continuing the introduction of the steam into the impulse turbine 7 when the energy of the steam introduced into the impulse turbine 7 becomes a first predetermined value or less. In particular, the ECU 17 estimates the energy of steam introduced into the impulse turbine 7 based on the amount of steam generated by collecting the waste heat of the engine body 2. In the following description, the predetermined amount A1 of the steam amount corresponds to the case where the energy of the steam is the first predetermined value, and the predetermined amount A2 of the steam amount corresponds to the case where the energy of the steam is the second predetermined value. .

  FIG. 3 is a flow showing control for switching the electromagnetic clutch 10 and the three-way valve 15. Hereinafter, the flow of FIG. 3 will be described. In step S11, the ECU 17 connects the opening 151 and the opening 152 of the three-way valve 15. Further, the ECU 17 energizes the coil 11, connects the electromagnetic clutch 10, and connects the power shaft 73 of the impulse turbine 7 and the crankshaft 32. In this state, power is recovered from the steam discharged from the engine body 2. The ECU 17 proceeds to step S12 after completing the process of step S11.

  In step S12, the ECU 17 acquires the amount of steam introduced into the impulse turbine 7 from the map. The map is created by measuring in advance the steam amount downstream of the superheater 6 when the engine speed and the engine load change. FIG. 4 is an explanatory view showing an example of such a map. As shown in FIG. 4, the vertical axis of the map represents torque (engine load), and the horizontal axis represents engine speed. The curve on the map is a line connecting points with the same amount of steam. The equivalence line of the vapor amount increases as the distance from the origin on the graph increases. In step S <b> 12, the ECU 17 compares the torque and the rotational speed of the engine 100 with the map, and acquires the amount of steam introduced into the impulse turbine 7. After completing step S12, the ECU 17 proceeds to step S13.

  In step S13, the ECU 17 determines whether or not the steam amount acquired in step S12 is less than the predetermined amount A1 and greater than the predetermined amount A2. If the amount of steam flowing into the impulse turbine 7 continues to decrease from the amount capable of recovering power, even if the impulse turbine 7 can be operated, power sufficient to assist the rotation of the crankshaft 32 cannot be obtained. The predetermined amount A1 is a minimum amount of steam that can recover power in the crankshaft 32. That is, when the amount of steam is less than the predetermined amount A1, the crankshaft 32 cannot obtain auxiliary power using energy recovered from waste heat. Moreover, if the power shaft 73 of the impulse turbine 7 and the crankshaft 32 are connected to each other, the friction for rotating the power shaft 73 is applied and the fuel efficiency is deteriorated. On the other hand, the predetermined amount A2 is a smaller amount than the predetermined amount A1. When the amount of heat exchanged in the water jackets 41 and 42 decreases, the temperature of the exhaust gas also decreases, so that the amount of generated steam decreases and the temperature of the steam also decreases. Condensation begins when the steam volume decreases and the steam temperature continues to drop further. The predetermined amount A2 is an amount of steam necessary for the turbine to maintain a certain rotational speed or more. If the ECU 17 determines that the amount of steam flowing into the impulse turbine 7 is less than the predetermined amount A1 and greater than the predetermined amount A2, the ECU 17 proceeds to step S14.

  In step S14, the ECU 17 stops energization of the coil 11 of the electromagnetic clutch 10. As a result, the coupling between the power shaft 73 of the impulse turbine 7 and the rotor 12 is released, the torque of the power shaft 73 is not transmitted to the crankshaft 32, and the impulse turbine 7 idles. At this time, the power is not recovered, but the steam is introduced into the impulse turbine 7, so that the impulse turbine 7 is maintained in an operating state. As a result, the torque and rotational speed of the engine rise again, and when the amount of steam introduced into the impulse turbine 7 exceeds the predetermined amount A1, the rotational speed of the impulse turbine 7 reaches the rotational speed at which power can be recovered quickly. To do. Thus, since the time until power recovery is shortened, the energy recovery efficiency of waste heat is improved. Further, since the coupling between the power shaft 73 of the impulse turbine 7 and the crankshaft 32 is released when the steam amount is lower than the predetermined amount A1, the torque transmitted from the crankshaft 32 to the power shaft 73 is suppressed, and the fuel consumption is deteriorated. Is suppressed. When the ECU 17 finishes the process of step S14, the process proceeds to step S15.

  In step S15, the ECU 17 determines whether or not the turbine speed is below a predetermined value N1. When the amount of generated steam decreases, the temperature of the steam also decreases. When the amount of steam continues to decrease, condensation of the steam begins. The predetermined value N1 is the turbine speed when the amount of steam is the predetermined amount A2. When the turbine rotation speed falls below a predetermined value N1, the liquid refrigerant generated by condensation in the impulse turbine 7 becomes resistance when the turbine wheel 74 rotates, and the recovery efficiency is reduced during power recovery. If the ECU 17 determines that the turbine speed is below the predetermined value N1, the ECU 17 proceeds to step S16.

  In step S <b> 16, the ECU 17 connects the opening 151 and the opening 153 of the three-way valve 15 and sends the steam flowing through the pipe 52 to the bypass passage 16. Further, the ECU 17 stops energization of the coil 11 and opens the connection between the power shaft 73 of the impulse turbine 7 and the rotor 12. Thereby, the connection state of the power shaft 73 and the crankshaft 32 is released. By this process, the introduction of steam into the impulse turbine 7 is suppressed, and the steam is prevented from condensing in the impulse turbine 7. Accordingly, an increase in the resistance of rotation of the turbine wheel 74 due to accumulation of liquid-phase refrigerant in the impulse turbine 7 is prevented, and a reduction in the recovery efficiency of waste heat energy is suppressed.

  After completing the process of step S16, the ECU 17 proceeds to step S12 and repeats the process of determining the steam amount again.

  Further, when the ECU 17 determines in step S15 that the turbine rotational speed does not fall below the predetermined value N1, the ECU 17 proceeds to step S12 and repeats the process for determining the steam amount again.

  When the ECU 17 determines in step S13 that the amount of steam flowing into the impulse turbine 7 is not less than the predetermined amount A1 or not more than the predetermined amount A2, the ECU 17 proceeds to step S17.

  In step S17, the ECU 17 determines whether or not the amount of steam flowing into the impulse turbine 7 is a predetermined amount A2 or less. If the amount of steam flowing into the impulse turbine 7 is less than or equal to the predetermined amount A2, the ECU 17 proceeds to step S16. On the other hand, when the amount of steam flowing into the impulse turbine 7 is not equal to or less than the predetermined amount A2, that is, when it is equal to or greater than the predetermined amount A1, the ECU 17 proceeds to step S11.

  According to the process of step S17, when the amount of steam flowing into the impulse turbine 7 is equal to or less than the predetermined amount A2, the steam flowing into the impulse turbine 7 may condense in the impulse turbine 7, so that the ECU 17 has the three-way valve 15 Thus, the flow is changed to a flow path in which the steam bypasses the impulse turbine 7. Moreover, since auxiliary power is not obtained and friction is increased, the ECU 17 opens the electromagnetic clutch 10. On the other hand, when the amount of steam flowing into the impulse turbine 7 is greater than or equal to the predetermined amount A1, the auxiliary power can be recovered by the impulse turbine 7, so the ECU 17 maintains the flow path of the pipe 52 as it is with the three-way valve 15, and the electromagnetic The coupling state of the clutch 10 is maintained.

  As described above, when the amount of steam introduced into the impulse turbine 7 is such an amount that the auxiliary power cannot be recovered, the waste heat recovery apparatus 1 opens the electromagnetic clutch 10 and causes the impulse turbine 7 to idle. Thereby, the friction concerning rotation of the power shaft 73 of the impulse turbine 7 is reduced, and deterioration of fuel consumption is suppressed. Furthermore, since the impulse turbine 7 is continuously operated, when the steam amount becomes an amount capable of recovering power, the impulse turbine 7 can be quickly increased to a recoverable rotational speed, and waste heat energy Recovery efficiency is improved.

  When the amount of steam introduced into the impulse turbine 7 is such that the steam is condensed in the impulse turbine 7, the introduction of the steam into the impulse turbine 7 is stopped, and the liquid refrigerant is introduced into the impulse turbine 7. Suppresses accumulation. Thereby, the rotational resistance of the power shaft 73 of the impulse turbine 7 is reduced, and the reduction in energy recovery efficiency is suppressed.

  Next, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment in that the control of the electromagnetic clutch 10 and the three-way valve 15 by the ECU 17 is different. In the present embodiment, when the energy of the steam introduced into the impulse turbine 7 is lower than the first predetermined value, the ECU 17 takes into account the inertial drive period and determines the predetermined energy according to the energy of the steam introduced into the impulse turbine 7. The electromagnetic clutch 10 is connected for a time. Further, when the energy of the steam introduced into the impulse turbine 7 is equal to or less than the second predetermined value, the ECU 17 takes into account the inertial drive period and determines a predetermined time according to the energy of the steam introduced into the impulse turbine 7. The introduction of steam into the impulse turbine 7 is continued. Further, as in the first embodiment, the ECU 17 estimates the energy of the steam introduced into the impulse turbine 7 based on the amount of steam generated by recovering the waste heat of the engine body 2. Note that the waste heat recovery apparatus of the present embodiment has the same configuration as the waste heat recovery apparatus 1 of the first embodiment. Therefore, the configuration of the apparatus will be described using the same numbers as in the first embodiment.

  FIG. 5 is a control flow for the electromagnetic clutch 10 and the three-way valve 15 in this embodiment. The control flow of the present embodiment is substantially the same as the flow of the first embodiment. The control of the present embodiment differs from the control of the first embodiment in that step S21 is performed instead of step S14, and step S22 is performed instead of step S16. In the flow of FIG. 5, the same steps as those in the flow of FIG.

  In step S21, the ECU 17 stops energization of the coil 11 of the electromagnetic clutch 10 after elapse of S1 seconds. Even if the amount of steam introduced into the impulse turbine 7 is below a predetermined amount A1 at which power recovery is impossible, the impulse turbine 7 rotates due to inertia for a while even if the amount of steam falls below the predetermined amount A1. In order to continue, there is an inertial drive period during which power can be recovered. Such an inertial drive period S1 second is determined by the amount of steam acquired in step S12 and the steam temperature in this state. This steam temperature can be obtained from a temperature sensor installed in the pipe or calculated from a map based on other temperature information correlated with the steam temperature.

  In step S22, the ECU 17 connects the opening 151 and the opening 153 of the three-way valve 15 after S2 seconds, and sends the steam flowing through the pipe 52 to the bypass passage 16. Even if the amount of steam generated in the engine main body 2 is equal to or less than the predetermined amount A2 that may condense in the impulse turbine 7, the impulse turbine is used for a while even if the amount of steam becomes the predetermined amount A2. Since 7 continues to rotate due to inertia, there is an inertial drive period in which the rotational speed of the turbine is equal to or greater than the predetermined value N1. When the amount of steam exceeds the predetermined amount A2 during such a period, since the idling turbine 7 is kept idle, the amount of steam further increases, and when the amount of steam can be recovered to a predetermined amount A1 or more, You can quickly move to power recovery. Such an inertial drive period S2 is determined by the amount of steam acquired in step S12 and the steam temperature in this state. This steam temperature can be acquired by the same method as in step S21.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

  For example, the steam amount estimated from the map in step S12 can be estimated based on the engine temperature of the engine. Further, a pressure sensor can be provided in the pipe 52, the pressure of steam introduced into the impulse turbine 7 can be measured, the amount of steam can be calculated based on the measured value of the pressure sensor, and the electromagnetic clutch 10 can be controlled.

DESCRIPTION OF SYMBOLS 1 Waste heat recovery apparatus 2 Engine main body 7 Impulse turbine 10 Electromagnetic clutch 11 Coil 12 Rotor 13 Pulley 15 Three-way valve 16 Bypass passage 17 ECU
32 Crankshaft 73 Power shaft 100 Engine

Claims (5)

In the waste heat recovery equipment that constitutes the Rankine cycle and recovers engine waste heat,
An expander that operates by introducing steam generated by engine waste heat;
Energy recovery means having a power input that operates in conjunction with the power shaft of the expander;
A clutch for connecting and releasing the power shaft and the power input unit;
With
The waste heat recovery apparatus, wherein when the energy of the steam introduced into the expander falls below a first predetermined value, the clutch is released while continuing the introduction of the steam into the expander. The waste heat recovery apparatus according to claim 1,
When the energy of the steam introduced into the expander is less than the first predetermined value, depending on the energy of the steam introduced into the expander, taking into account the first inertial drive period of the power input unit, The waste heat recovery apparatus, wherein the clutch is engaged during the first inertial drive period. The waste heat recovery apparatus according to claim 1 or 2,
Waste comprising: bypass means for bypassing the expander when the energy of the steam introduced into the expander is equal to or less than a second predetermined value that is smaller than the first predetermined value. Heat recovery device. The waste heat recovery apparatus according to claim 3,
When the energy of the steam introduced into the expander is equal to or less than the second predetermined value, the second inertial drive period of the power input unit is taken into account according to the energy of the steam introduced into the expander. The waste heat recovery apparatus is characterized in that the introduction of steam to the expander is continued for a predetermined time during the second inertial drive period. The waste heat recovery apparatus according to any one of claims 1 to 4,
A waste heat recovery apparatus that estimates energy of steam introduced into the expander based on an amount of steam generated by recovering waste heat of an engine.

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