JP2010138762A - Exhaust heat recovery system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize, when recovering heat energy of the exhaust heat discharged from a heat engine by an exhaust heat recovery engine, surplus power generated by the exhaust heat recovery engine while the heat engine is at rest. <P>SOLUTION: The exhaust heat recovery system 10 comprises a Stirling engine 100 that recovers heat energy from the exhaust gas Ex discharged from an internal combustion engine 1, a generator 2 driven by the Stirling engine 100, a storage battery 8 for storing power generated by the generator 2, and a charge and discharge control part 24 that is implemented as a function of an electronic control unit ECU 20 of the engine. While the internal combustion engine 1 is at rest, the charge and discharge control part 24 switches between the charge to the storage battery 8 and the discharge from the storage battery 8 based on the result of comparison between the electric energy generated by the Stirling engine 100 and the electric energy required by auxiliary machines of the vehicle on which the exhaust heat recovery system 10 is mounted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exhaust heat recovery system that generates power by recovering thermal energy from exhaust gas of a heat engine.

  There is an exhaust heat recovery engine that recovers exhaust heat of an internal combustion engine mounted on a vehicle such as a passenger car, a bus, or a truck by using a heat engine. As the exhaust heat recovery engine used for such an application, for example, an external combustion engine such as a Stirling engine having excellent theoretical thermal efficiency is used. Patent Document 1 includes an internal combustion engine, a Stirling engine that recovers thermal energy from the exhaust gas of the internal combustion engine, and a generator that is driven by the Stirling engine, and the exhaust that drives the generator by the Stirling engine when the internal combustion engine is stopped. A heat recovery device is disclosed.

JP 2007-270684 A

  By the way, when a Stirling engine is used as an exhaust heat recovery engine, thermal energy is acquired from a heat source via a heater. However, the exhaust heat recovery engine generates power even after heat input is stopped by heat stored in the heater. May continue. The exhaust heat recovery device disclosed in Patent Document 1 converts the power obtained from the Stirling engine after the heat input is stopped into electric power and stores it in the storage battery, but effectively uses the surplus power obtained by the heat stored in the heater. There is room for improvement in use.

  The present invention has been made in view of the above, and in recovering the heat energy of the exhaust heat discharged from the heat engine by the exhaust heat recovery engine, surplus generated by the exhaust heat recovery engine when the heat engine is stopped. The purpose is to make effective use of the power.

  In order to achieve the above object, an exhaust heat recovery system according to the present invention generates power and recovers heat energy from exhaust gas discharged from a heat engine mounted on a vehicle to generate power. A generator that generates electric power by being driven by the exhaust heat recovery engine, a power storage unit that can store the electric power generated by the generator, and an amount of power generated by the exhaust heat recovery engine when the heat engine is stopped And charge / discharge control means for switching between charging to the power storage means and discharging from the power storage means based on a result of comparison with a required power amount of an auxiliary machine mounted on the vehicle and operating with electric power. It is characterized by.

  With such a configuration, for example, even when the power storage means is in a fully charged state and cannot be charged any more, the electric power generated by the surplus power generated by the exhaust heat recovery engine is mounted on the vehicle as electric power. Can be supplied to auxiliary machines operating in As a result, the electric power generated by the surplus power is not wasted due to electric resistance or the like. As a result, the exhaust heat recovery system according to the present invention recovers excess heat generated by the exhaust heat recovery engine when the heat engine is stopped when recovering the heat energy of the exhaust heat exhausted from the heat engine by the exhaust heat recovery engine. Can be used effectively.

  As a preferred aspect of the present invention, in the exhaust heat recovery system, the charge / discharge control means, when the power generation amount by the exhaust heat recovery engine is larger than the required power amount of the auxiliary machine, When the difference from the required power amount is charged to the power storage means and the amount of power generated by the exhaust heat recovery engine is lower than the required power amount of the auxiliary machine, the shortage of the required power amount is compensated from the power storage means to the supplementary power. It is desirable to supply to the machine. When the amount of power generated by the exhaust heat recovery engine is equal to the required power amount of the auxiliary machine, the charge / discharge control means drives the auxiliary machine with the electric power generated by the exhaust heat recovery engine. In this case, the charge / discharge control means does not charge or discharge the power storage means.

  As a preferred aspect of the present invention, in the exhaust heat recovery system, the auxiliary machine is preferably an electric motor that drives a compressor of a vehicle air conditioner mounted on the vehicle.

  According to a preferred aspect of the present invention, in the exhaust heat recovery system, the charge / discharge control means includes a power generation amount by the exhaust heat recovery engine and the vehicle when the vehicle stops and the heat engine stops. It is desirable to switch between charging of the power storage means and discharging from the power storage means based on a comparison result with the required power amount of the auxiliary machine that is mounted and operates with power.

  As a preferred aspect of the present invention, in the exhaust heat recovery system, it is desirable that the heat engine is an internal combustion engine mounted on the vehicle, and the exhaust heat recovery engine is a Stirling engine mounted on the vehicle.

  The present invention can effectively use surplus power generated by the exhaust heat recovery engine when the heat engine is stopped when recovering the heat energy of the exhaust heat discharged from the heat engine by the exhaust heat recovery engine.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements disclosed below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. In the following description, a case where a Stirling engine is used as the exhaust heat recovery engine and thermal energy is recovered from the exhaust gas of the internal combustion engine, which is a heat engine, is taken as an example. As the exhaust heat recovery engine, an external combustion engine is preferable, and in addition to the Stirling engine, an exhaust heat recovery engine using a Brayton cycle may be used. Moreover, the kind of heat engine which is the collection object of exhaust heat is not ask | required.

(Embodiment)
The present embodiment is an exhaust heat recovery system that recovers thermal energy of heat exhausted from a heat engine by an exhaust heat recovery engine. When the heat engine is stopped, the amount of power generated by the exhaust heat recovery engine is Thus, there is a feature in that charging to the power storage means and discharging from the power storage means are switched based on the comparison result with the required power amount of the auxiliary machine that operates with electric power. First, the configuration of the exhaust heat recovery engine according to the present embodiment will be described.

  FIG. 1 is a cross-sectional view showing a Stirling engine that is an exhaust heat recovery engine according to the present embodiment. A Stirling engine 100 that is an exhaust heat recovery engine according to the present embodiment is a so-called α-type in-line two-cylinder Stirling engine. A high temperature side piston 103 that is a first piston housed in a high temperature side cylinder 101 that is a first cylinder, and a low temperature side piston 104 that is a second piston housed in a low temperature side cylinder 102 that is a second cylinder. Are arranged in series.

  The high temperature side cylinder 101 and the low temperature side cylinder 102 are directly or indirectly supported and fixed to a substrate 111 which is a reference body. In the Stirling engine 100 according to the present embodiment, the substrate 111 serves as a position reference for each component of the Stirling engine 100. Further, as will be described later, in the Stirling engine 100 according to the present embodiment, the gas bearing GB is interposed between the high temperature side cylinder 101 and the high temperature side piston 103 and between the low temperature side cylinder 102 and the low temperature side piston 104. .

  Between the high temperature side cylinder 101 and the low temperature side cylinder 102, a heat exchanger 108 including a substantially U-shaped heater (heater) 105, a regenerator 106, and a cooler (cooler) 107 is disposed. . A working fluid (air in this embodiment) is sealed in the high temperature side cylinder 101, the low temperature side cylinder 102, and the heat exchanger 108, and a Stirling cycle is performed by heat supplied from the heater 105 and heat discharged from the cooler 107. Configure and drive the Stirling engine 100.

  One end of the heater 105 is connected to the high temperature side cylinder 101 so that the working fluid flows in and out between the high temperature side cylinder 101 and the heater 105, and the other end is connected to the regenerator 106 to regenerate with the heater 105. The working fluid flows in and out of the vessel 106. The regenerator 106 is connected to the cooler 107 at the end opposite to the side connected to the heater 105, and the working fluid flows in and out between the regenerator 106 and the cooler 107. An end of the cooler 107 opposite to the side to which the regenerator 106 is connected is connected to the low temperature side cylinder 102, and the working fluid flows in and out between the cooler 107 and the low temperature side cylinder 102.

  In the heat exchanger 108, at least the heater 105 is disposed in the exhaust passage 5. The exhaust passage 5 uses, for example, a passage for exhaust gas Ex discharged from an internal combustion engine that is an exhaust heat recovery target. The heater 105 heats the working fluid in the heater 105 with heat energy from the exhaust gas Ex flowing through the exhaust passage 5. Note that the regenerator 106 of the heat exchanger 108 may be disposed in the exhaust passage 5. In the present embodiment, the exhaust gas Ex flows from the high temperature side cylinder 101 side toward the low temperature side cylinder 102 side. As a result, the exhaust gas Ex discharged from the heat engine is supplied to the heater 105 in a state in which the temperature decrease is suppressed, so that the thermal energy of the exhaust gas Ex can be efficiently recovered.

  As shown in FIG. 1, the constituent elements such as the high temperature side cylinder 101, the high temperature side piston 103, the connecting rod 109, and the crankshaft 110 that constitute the Stirling engine 100 are stored in a casing 100C. Here, the housing 100C of the Stirling engine 100 includes a crankcase 114A and a cylinder block 114B. The inside of the housing 100C is pressurized by the pressurizing means 115. This is because the working fluid in the high temperature side and low temperature side cylinders 101 and 102 and the heat exchanger 108 is pressurized to extract more output from the Stirling engine 100.

  As described above, the high temperature side piston 103 and the low temperature side piston 104 are supported in the high temperature side cylinder 101 and the low temperature side cylinder 102 via the gas bearing GB. That is, the piston is supported in the cylinder without using a piston ring. Thereby, the friction between the piston and the cylinder can be reduced, and the thermal efficiency of the Stirling engine 100 can be improved. Further, by reducing the friction between the piston and the cylinder, for example, the Stirling engine 100 can be recovered by recovering thermal energy even under a low heat source and low temperature difference operating condition such as exhaust heat recovery of an internal combustion engine. .

  Each of the high temperature side piston 103 and the low temperature side piston 104 has a hollow structure. That is, it has a space (internal space) surrounded by the top, sides, and partition of the piston. An air supply port 120 that communicates the internal space 103I and the outside of the high temperature side piston 103 is formed at the side of the high temperature side piston 103, and the internal space 104I and the low temperature side are formed at the side of the low temperature side piston 104. An air supply port 121 that communicates with the outside of the piston 104 is formed.

  Gas (working fluid in this embodiment) is supplied to each of the internal spaces 103I and 104I from a gas bearing pump 130, which is a gas bearing pressure generating means, disposed inside the housing 100C. The gas supplied to each of the internal spaces 103I and 104I flows out of the air supply ports 120 and 121 toward the high temperature side cylinder 101 and the low temperature side cylinder 102, thereby forming a gas bearing GB. The gas bearing pump 130 may be disposed outside the housing 100C. However, by disposing the gas bearing pump 130 inside the housing 100C as in the present embodiment, the gas bearing pump 130 causes the working fluid in the housing 100C pressurized by the pressurizing means 115 to flow into the internal space. Since it is only sent to 103I and 104I, the work amount of the gas bearing pump 130 required for forming the gas bearing GB can be reduced.

  In the Stirling engine 100, a seal bearing 116 is attached to the housing 100C, and the crankshaft 110 is supported by the seal bearing 116. The crankshaft 110 serves as an output shaft of the Stirling engine 100, and the power generated by the Stirling engine 100 is taken out of the housing 100C through a flexible coupling 118 such as an Oldham coupling. Next, the configuration of the exhaust heat recovery system according to the present embodiment will be described.

  FIG. 2 is a plan view showing the configuration of the exhaust heat recovery system according to the present embodiment. FIG. 3 is a conceptual diagram showing a state in which the exhaust heat recovery system according to the present embodiment is mounted on a vehicle. The exhaust heat recovery system 10 is mounted on a vehicle and serves as a power generation source. The exhaust heat recovery system 10 according to the present embodiment includes a Stirling engine 100 that is an exhaust heat recovery engine, a clutch 6E that is a power interrupting means, and a generator (M / G) 2.

  As shown in FIG. 3, the internal combustion engine 1 and the Stirling engine 100 are mounted on a vehicle 50 such as a passenger car or a truck and serve as a power generation source of the vehicle 50. The internal combustion engine 1 always generates an output as a main power generation source while the vehicle 50 is traveling. In the exhaust heat recovery system 10, the Stirling engine 100 is disposed in the vicinity of the internal combustion engine 1 that is a heat engine for exhaust heat recovery.

  The heater 105 of the Stirling engine 100 is disposed in the exhaust passage 5 of the internal combustion engine 1. The Stirling engine 100 generates power by recovering the thermal energy of the exhaust gas Ex discharged from the internal combustion engine 1 from the heater 105. This power is extracted from the crankshaft (exhaust heat recovery engine output shaft) 110 of the Stirling engine 100. A Stirling engine pulley 3AS is attached to the crankshaft 110 of the Stirling engine 100. An internal combustion engine pulley 3E is attached to the output shaft 1s of the internal combustion engine 1. A belt 4 serving as power transmission means is wound around the pulley 3AS for Stirling engine and the pulley 3E for internal combustion engine.

  In the exhaust heat recovery system 10, the power generated by the Stirling engine 100 is transmitted to the output shaft 1 s of the internal combustion engine 1 and is taken out from the output shaft 1 s of the internal combustion engine 1 together with the power generated by the internal combustion engine 1. In the exhaust heat recovery system 10, the generator 2 can be driven by the Stirling engine 100 to convert the heat energy of the exhaust gas Ex of the internal combustion engine 1 into electric energy and recover it. In this case, the clutch 6E is released, and the generator 2 is driven by the Stirling engine 100 alone. For example, when the vehicle 50 is stopped by a signal or the like, the internal combustion engine 1 may be stopped in order to suppress the fuel consumption of the internal combustion engine 1, but even in such a case, the heater 105 of the Stirling engine 100 may be stopped. The Stirling engine 100 generates power by the stored residual heat. For this reason, when the internal combustion engine 1 stops, the clutch 6E is released, the generator 2 is driven by the Stirling engine 100 alone, and the remaining heat of the heater 105 is recovered as electric power.

  The clutch 6E that is a power interrupting means is provided between the internal combustion engine 1 that is a heat engine and the Stirling engine 100 that is an exhaust heat recovery engine, and between the internal combustion engine 1 and the generator 2. In the present embodiment, a clutch 6E is attached to the output shaft 1s of the internal combustion engine 1 between the internal combustion engine 1 and the pulley 3E for the internal combustion engine. Thereby, the power of the Stirling engine 100 input to the output shaft 1s of the internal combustion engine 1 from the pulley 3E for the internal combustion engine can be interrupted.

  When the clutch 6E is engaged, that is, engaged, the crankshaft 110 of the Stirling engine 100 and the output shaft 1s of the internal combustion engine 1 are mechanically connected. Thus, the Stirling engine 100 and the internal combustion engine 1 are connected, and the power generated by the Stirling engine 100 is transmitted to the output shaft 1s of the internal combustion engine 1 via the clutch 6E. Further, when the clutch 6E is disconnected, that is, released, the connection between the internal combustion engine 1 and the Stirling engine 100 is released (becomes a disconnected state), so that the internal combustion engine pulley 3E is connected to the output shaft 1s of the internal combustion engine 1. The power of the Stirling engine 100 is not transmitted.

  The operation of the clutch 6E is controlled by a clutch control unit 23 of an exhaust heat recovery control device 21 provided in an engine ECU (Electronic Control Unit) 20. Here, the exhaust heat recovery control device 21 manages the control function of the exhaust heat recovery system 10 provided in the engine ECU 20, and is realized as one function of the engine ECU 20. The exhaust heat recovery control device 21 is configured to include an operation state determination unit 22, a clutch control unit 23, and a charge / discharge control unit 24 that is a charge / discharge control unit. The operation of the heat recovery system 10 is controlled.

  An input shaft 2s of the generator 2 is attached to the Stirling engine pulley 3AS. The generator 2 is driven by the Stirling engine 100 via the crankshaft 110 of the Stirling engine 100 and the input shaft 2s of the generator 2. Thereby, the generator 2 generates electric power. When the Stirling engine 100 stops, the power generation by the generator 2 stops.

  With such a configuration, the exhaust heat recovery system 10 drives the generator 2 with the power generated by the Stirling engine 100 by engaging / releasing the clutch 6E, or uses the power generated by the Stirling engine 100 as internal combustion. Whether to take out from the output shaft 1 s of the internal combustion engine 1 together with the power generated by the engine 1 can be selected. In the latter case, the generator 2 is driven by a part of the power generated by the Stirling engine 100 or a part of the power generated by the internal combustion engine 1.

  Here, the generator 2 charges the storage battery 8 serving as a power storage means, or an auxiliary device of the vehicle 50 on which the exhaust heat recovery system 10 is mounted, for example, the compressor (air conditioner compressor) 9 of the vehicle air conditioner or the electric power. It supplies power to drive steering motors, brake actuators, lights, and the like. This auxiliary machine is an auxiliary machine that operates on electric power.

  The electric power obtained by the generator 2 is supplied to the storage battery 8 or supplied to the auxiliary equipment of the vehicle 50 via the power distribution device 7 having a rectification function and a power distribution function. Moreover, when the electric power obtained by the generator 2 is less than the required power of the auxiliary machine, the power distribution device 7 supplies the shortage from the storage battery 8 to the auxiliary machine. The power storage means stores power generated by approaching the generator 2, and is not limited to the storage battery 8, but may be a capacitor, for example. The air conditioner compressor 9 includes a compressor 9C and a compressor motor 9M that drives the compressor 9C.

  FIG. 4 is a plan view showing a configuration of an exhaust heat recovery engine according to a modification of the present embodiment. The exhaust heat recovery system 10 a according to this modification is substantially the same as the above-described exhaust heat recovery system 10 except that the Stirling engine 100 drives the generator 2 via the belt 4. Other configurations are the same as those of the exhaust heat recovery system 10 described above.

  A belt 4 serving as power transmission means is wound around a Stirling engine pulley 3AS attached to the crankshaft 110 of the Stirling engine 100 and an internal combustion engine pulley 3E attached to the output shaft 1s of the internal combustion engine 1. With such a configuration, the power generated by the Stirling engine 100 is transmitted to the output shaft 1 s of the internal combustion engine 1. The power generated by the Stirling engine 100 is extracted from the output shaft 1 s of the internal combustion engine 1 together with the power generated by the internal combustion engine 1.

  The generator 2 is driven by power input from the input shaft 2s of the generator 2 to generate electric power. A generator pulley 3 </ b> A is attached to the input shaft 2 s and is driven by at least one of the Stirling engine 100 and the internal combustion engine 1 via the belt 4. That is, when the clutch 6E is engaged, the generator 2 is driven by the Stirling engine 100 and the internal combustion engine 1, and when the clutch 6E is released, the generator 2 is driven by the Stirling engine 100. With such a configuration, the generator 2 can be driven by the Stirling engine 100 by releasing the clutch 6E when there is no drive request for the internal combustion engine 1 (for example, when the internal combustion engine is stopped by idling stop).

  FIG. 5 is a plan view showing a configuration of an exhaust heat recovery engine according to a modification of the present embodiment. In the exhaust heat recovery system 10b according to this modification, the power of the Stirling engine 100 is not combined with the output of the internal combustion engine 1, and the Stirling engine 100 alone drives the generator 2. Other configurations are the same as those of the exhaust heat recovery system 10 described above. According to this configuration, the power of the Stirling engine 100 cannot be combined with the power of the internal combustion engine 1, but the clutch 6E shown in FIG. 3 is not required, so that the system configuration can be simplified. Since the exhaust heat recovery system 10b does not include the clutch 6E, the clutch control unit 23 of the exhaust heat recovery control device 21 is unnecessary.

  FIG. 6 is a flowchart illustrating a control example of the exhaust heat recovery system according to the present embodiment. FIG. 7 is a timing chart showing a control example of the exhaust heat recovery system according to the present embodiment. In the following description, the exhaust heat recovery system 10 is taken as an example, but the basic control is the same in the other exhaust heat recovery systems 10a and 10b. This control of the exhaust heat recovery system is effective when an eco-run (or idling stop) for stopping the internal combustion engine 1 is executed when the vehicle 50 equipped with the exhaust heat recovery system 10 is stopped by a signal or the like. This is control for recovering exhaust heat.

  In the present embodiment, when the operation of the internal combustion engine 1 is stopped, the power generation amount obtained by driving the generator by the Stirling engine 100 and an auxiliary device mounted on the vehicle 50 and operating with electric power (in this embodiment, an air conditioner compressor). Based on the comparison result with the required power amount of 9), the charging to the storage battery 8 and the discharging from the storage battery 8 are switched. This function is realized by the charge / discharge control unit 24 of the exhaust heat recovery control device 21 provided in the engine ECU 20. By controlling the exhaust heat recovery system 10 during the eco-run, the exhaust heat can be effectively recovered during the eco-run. Next, a control procedure of the exhaust heat recovery system according to the present embodiment will be described.

  In the example shown in FIG. 7, the vehicle 50 starts decelerating at time t = t1, and the output We of the internal combustion engine 1 gradually decreases. On the other hand, since the Stirling engine 100 has a large heat capacity of the heater 105, heat is stored in the heater 105. Due to the remaining heat, the output Ws of the Stirling engine 100 (corresponding to the amount of power generated by the generator 2 in this embodiment) Ws starts to decrease after the decrease in the output We of the internal combustion engine 1 (immediately before time t = t2). . In the example shown in FIG. 7, the air conditioner compressor 9 which is an auxiliary machine mounted on the vehicle 50 and driven by electric power is operated with a constant load. That is, the required power of the air conditioner compressor 9 is Wh.

  When the vehicle 50 stops, the engine ECU 20 performs an eco-run to stop the internal combustion engine 1. When the power generated by the Stirling engine 100 is combined with the power generated by the internal combustion engine 1, the clutch 6E is engaged. In this case, before the engine ECU 20 stops the internal combustion engine 1, the clutch control unit 23 of the exhaust heat recovery control device 21 provided in the engine ECU 20 releases the clutch 6E, and the output shaft 1s of the internal combustion engine 1 and the Stirling engine 100 crankshafts 110 are disconnected. Thus, the Stirling engine 100 is not stopped even when the internal combustion engine 1 is stopped, and the generator 2 can be driven by the Stirling engine 100 alone. When power is generated with the power generated by the Stirling engine 100 during operation of the internal combustion engine 1, the clutch 6E is released, so the clutch control unit 23 maintains the state where the clutch 6E is released. The exhaust heat recovery system 10b shown in FIG. 5 has a configuration in which the generator 2 is driven by the Stirling engine 100 alone and does not include the clutch 6E, and thus the above-described operation is unnecessary.

  In step S101, the operating state determination unit 22 of the exhaust heat recovery control device 21 provided in the engine ECU 20 determines whether or not the vehicle 50 is executing an eco-run. That is, it is determined whether or not the internal combustion engine 1 mounted on the vehicle 50 is stopped. This determination may be based on a stop command for the internal combustion engine 1 transmitted from the engine ECU 20, or may be based on the rotational speed of the output shaft 1s of the internal combustion engine 1. When based on the rotational speed of the output shaft 1 s of the internal combustion engine 1, the operating state determination unit 22, for example, when the rotational speed of the output shaft 1 s of the internal combustion engine 1 detected from the crank angle sensor of the internal combustion engine 1 is 0, When the ignition key of the vehicle 50 is ON, it is determined that the vehicle 50 is performing an eco-run.

  When it is determined Yes in step S101, that is, when the driving state determination unit 22 determines that the vehicle 50 is executing an eco-run (E / G stop after time t = t2), the process proceeds to step S102. In step S102, the charge / discharge control unit 24 of the exhaust heat recovery control device 21 provided in the engine ECU 20 generates the power generation amount by the Stirling engine 100, that is, the power generation amount Ws of the generator 2 driven by the Stirling engine 100, and the air conditioner compressor. 9 is compared with the required power amount Wh.

  When it is determined Yes in step S102, that is, when the charge / discharge control unit 24 determines that the power generation amount Ws by the Stirling engine 100 is larger than the required power amount Wh of the air conditioner compressor 9 (Ws> Wh), A surplus occurs in the power generation amount Ws. In this case, the process proceeds to step S103, and the charge / discharge control unit 24 controls the power distribution device 7 to charge the storage battery 8 with the difference (Ws−Wh) between the power generation amount Ws and the required power amount Wh. The area corresponding to the portion indicated by A in FIG. 7 corresponds to the amount of power charged in the storage battery 8.

  When it is determined No in step S102, that is, when the charge / discharge control unit 24 determines that the power generation amount Ws by the Stirling engine 100 is equal to or less than the required power amount Wh of the air conditioner compressor 9 (Ws ≦ Wh), Proceed to step S104. In step S <b> 104, the charge / discharge control unit 24 determines whether the power generation amount Ws by the Stirling engine 100 is equal to the required power amount Wh of the air conditioner compressor 9.

  When it is determined No in step S104, that is, when the charge / discharge control unit 24 determines that the power generation amount Ws by the Stirling engine 100 is lower than the required power amount Wh of the air conditioner compressor 9 (Ws <Wh), the request is made. A shortage occurs in the amount of power Wh. For example, when the remaining heat stored in the heater 105 of the Stirling engine 100 is consumed, the power generation amount Ws decreases and falls below the required power amount Wh. In this case, the process proceeds to step S105, and the charge / discharge control unit 24 controls the power distribution device 7 to discharge the difference (Wh−Ws) between the required power amount Wh and the power generation amount Ws from the storage battery 8, and the air conditioner compressor 9 is supplied. The area indicated by C in FIG. 7 corresponds to the amount of power discharged from the storage battery 8 and supplied to the air conditioner compressor 9.

  When it is determined Yes in step S104, that is, when the charge / discharge control unit 24 determines that the power generation amount Ws by the Stirling engine 100 is equal to the required power amount Wh of the air conditioner compressor 9 (Ws = Wh), the air conditioner compressor The required power amount Wh of 9 can be covered by the power generation amount Ws of the Stirling engine 100. In this case, since the storage battery 8 does not need to be charged or discharged, the process proceeds to step S106. In step S106, the charge / discharge control unit 24 controls the power distribution device 7 to supply all the electric power generated by the Stirling engine 100 to the air conditioner compressor 9, and neither charge nor discharge the storage battery 8. I won't let you. In this way, the charge / discharge control unit 24 switches between charging the storage battery 8 and discharging from the storage battery 8 based on the comparison result between the power generation amount Ws by the Stirling engine 100 and the required power amount Wh of the air conditioner compressor 9.

  When step S103 or step S105 or step S106 is executed, the process returns to step S101. And when it determines with No by step S101, ie, when the driving | running state determination part 22 determines with the vehicle 50 not performing eco-run, this control is complete | finished. For example, when the internal combustion engine 1 is started and the vehicle 50 starts, the eco-run of the vehicle 50 ends. Therefore, it is determined No in step S101, and this control ends. In the example shown in FIG. 7, the eco-run ends at time t = t3, the vehicle 50 starts and accelerates, and shifts to steady running (the output We of the internal combustion engine 1 is constant) at time t = t4.

  During the eco-run of the vehicle 50, by controlling the exhaust heat recovery system 10 as described above, if there is a margin in the power generation amount Ws by the Stirling engine 100, the surplus is stored in the storage battery 8, and the power generation by the Stirling engine 100 is performed. When there is no allowance for the amount Ws, the shortage is taken out from the storage battery 8. As a result, the surplus power generated by the Stirling engine 100 is not wasted due to electric resistance or the like, so that exhaust heat can be effectively recovered and used during an eco-run (ie, when the internal combustion engine 1 is stopped). Moreover, since the driving force shortage of the air conditioner compressor 9 can be suppressed, the on-vehicle air conditioner can be stably operated. Further, there are many occasions where the vehicle air conditioner is used while the vehicle 50 is traveling. For this reason, the air conditioner compressor 9 is preferable because it is a stable supply target of the power generated by the Stirling engine 100.

  8 and 9 are timing charts showing an example of controlling the exhaust heat recovery system according to the present embodiment when the required power amount of the auxiliary machine is zero. When the eco-run is executed when the required electric energy Wh of the auxiliary machine mounted on the vehicle 50 and driven by electric power, for example, the air conditioner compressor 9 is 0 (E / G stop after time t = t2 in FIG. 8) The charge / discharge control unit 24 controls the power distribution device 7 to charge the storage battery 8 with the entire power generation amount Ws by the Stirling engine 100. The area of the portion indicated by D in FIG. 8 corresponds to the amount of power charged in the storage battery 8. At time t = t3, the eco-run ends and the vehicle 50 starts and accelerates. At time t = t4, the vehicle moves to steady running (the output We of the internal combustion engine 1 is constant).

  Note that when the clutch 6E is engaged during the operation of the internal combustion engine 1 (a period up to time t = t2 in FIG. 8), the clutch control unit 23 starts the eco-run, that is, before the internal combustion engine 1 stops. Release the clutch 6E. When the eco-run is started and the internal combustion engine 1 is stopped, the generator 2 generates power to an auxiliary machine (for example, an air conditioner compressor 9) mounted on the vehicle 50 and driven by electric power instead of charging the storage battery 8. It may be operated by supplying power.

  FIG. 9 shows an example of control when the internal combustion engine 1 stops other than the eco-run. When the required electric energy Wh of the air conditioner compressor 9 is 0 and the internal combustion engine 1 is stopped other than the eco-run (E / G stop after time t = t2 in FIG. 9), the charge / discharge control unit 24 7, the storage battery 8 is charged with the entire power generation amount Ws by the Stirling engine 100. The area indicated by E in FIG. 9 corresponds to the amount of power charged in the storage battery 8. If the clutch 6E is engaged during the operation of the internal combustion engine 1 (period until time t = t2 in FIG. 9), the clutch control unit 23 releases the clutch 6E before the internal combustion engine 1 stops. .

  As described above, in the present embodiment, when the operation of the internal combustion engine 1 is stopped, the charging of the storage battery 8 and the storage battery 8 are based on the comparison result between the power generation amount by the Stirling engine 100 and the required power amount of the auxiliary machine of the vehicle 50. Switch between discharge and. As a result, even if the required power amount of the auxiliary equipment of the vehicle 50 is 0, the heat energy recovered from the exhaust heat is converted into electricity and stored in the storage battery 8, so that the exhaust heat is effective when the internal combustion engine 1 is stopped. Can be recovered and used.

  As described above, the exhaust heat recovery system according to the present invention is useful for power generation by an exhaust heat recovery engine that recovers thermal energy discharged from a heat engine.

It is sectional drawing which shows the Stirling engine which is a waste heat recovery engine which concerns on this embodiment. It is a top view which shows the structure of the waste heat recovery system which concerns on this embodiment. It is a key map showing the state where the exhaust heat recovery system concerning this embodiment was carried in vehicles. It is a top view which shows the structure of the waste heat recovery engine which concerns on the modification of this embodiment. It is a top view which shows the structure of the waste heat recovery engine which concerns on the modification of this embodiment. It is a flowchart which shows the example of control of the waste heat recovery system which concerns on this embodiment. It is a timing chart which shows the example of control of the exhaust heat recovery system concerning this embodiment. It is a timing chart which shows the example which controls the exhaust heat recovery system which concerns on this embodiment, when the required electric energy of an auxiliary machine is 0. It is a timing chart which shows the example which controls the exhaust heat recovery system which concerns on this embodiment, when the required electric energy of an auxiliary machine is 0.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Generator 3A Generator pulley 3AS Stirling engine pulley 3E Internal engine pulley 4 Belt 5 Exhaust passage 6E Clutch 7 Power distribution device 8 Storage battery 9 Air conditioner compressor 9C Compressor 9M Compressor motor 10, 10a, 10b Waste heat recovery system 20 Engine ECU
DESCRIPTION OF SYMBOLS 21 Waste heat recovery control apparatus 22 Operation state determination part 23 Clutch control part 24 Charge / discharge control part 50 Vehicle 100 Stirling engine 101 High temperature side cylinder 102 Low temperature side cylinder 103 High temperature side piston 104 Low temperature side piston 105 Heater 106 Regenerator 107 Cooler 108 Heat Exchanger 110 Crankshaft 120, 121 Air supply port

Claims (5)

An exhaust heat recovery engine that generates power by generating thermal power from exhaust gas that is generated by a heat engine mounted on the vehicle and generating power;
A generator driven by the exhaust heat recovery engine to generate electric power;
Power storage means capable of storing the power generated by the generator;
When the heat engine is stopped, charging to the power storage means and the power storage based on a comparison result between the amount of power generated by the exhaust heat recovery engine and the required power amount of an auxiliary machine mounted on the vehicle and operating with power. Charge / discharge control means for switching between discharge from the means;
An exhaust heat recovery system comprising: The charge / discharge control means includes
When the amount of power generated by the exhaust heat recovery engine is greater than the required power amount of the auxiliary machine, the difference between the generated power amount and the required power amount is charged to the power storage means,
2. The exhaust heat recovery system according to claim 1, wherein when the amount of power generated by the exhaust heat recovery engine is less than the required power amount of the auxiliary machine, the shortage of the required power amount is supplied from the power storage unit to the auxiliary machine. .   The exhaust heat recovery system according to claim 1 or 2, wherein the auxiliary machine is an electric motor that drives a compressor of a vehicle air conditioner mounted on the vehicle. The charge / discharge control means includes
When the vehicle is stopped and the heat engine is stopped, the power storage based on the result of comparison between the amount of power generated by the exhaust heat recovery engine and the required power amount of an auxiliary device mounted on the vehicle and operating with electric power. The exhaust heat recovery system according to any one of claims 1 to 3, wherein switching between charging to the means and discharging from the power storage means is performed.   The exhaust heat recovery system according to any one of claims 1 to 4, wherein the heat engine is an internal combustion engine mounted on the vehicle, and the exhaust heat recovery engine is a Stirling engine mounted on the vehicle.

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