JP2015071982A - Control device of gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas engine control device capable of improving the efficiency of a gas engine used in a gas engine cogeneration system or GHP. An engine control device 30 enables a gas engine cogeneration system 1 to generate an electric energy amount corresponding to a required electric energy amount H based on output characteristics with respect to the rotational speed of a gas engine 11 during a mirror cycle operation. In addition, the rotational speed control unit 31 that controls the rotational speed of the gas engine 11 and the operation state of the gas engine 11 is the mirror cycle operation when the predicted thermal energy amount H1 is equal to or greater than the required thermal energy amount H. An operation state control unit 32 that controls the operation state of the gas engine 11 is provided so that the operation state of the gas engine becomes a normal cycle operation when H1 is less than the required heat energy amount H. [Selection] Figure 8

Description

  The present invention relates to a control device for a gas engine, and more particularly to a control device for a gas engine used in a gas engine cogeneration system or a gas heat pump.

  The gas engine cogeneration system generates electrical energy by driving a generator using the driving output (rotational output) of the gas engine, and uses (recovers) the exhaust heat of the gas engine to generate thermal energy. Generate. Patent documents 1 and 2 disclose a regenerative gas engine cogeneration system.

JP-A-6-193998 JP-A-3-99142

(Problems to be solved by the invention)
A gas engine used in a gas engine cogeneration system is normally operated at a constant engine speed so that a constant amount of electrical energy can be extracted. However, the amount of electrical energy required from the electric load to the gas engine cogeneration system (the amount of required electrical energy) varies. Therefore, a gas engine cogeneration system configured to convert surplus electrical energy into heat energy and supply the converted heat energy to a heat load when the amount of generated electric energy is larger than the required amount of electric energy is proposed. Is done. However, when the amount of heat energy required for the gas engine cogeneration system from the heat load (required heat energy amount) is small or when heat energy is unnecessary, the converted heat energy is wasted. In other words, in a situation where the amount of generated electric energy is greater than the required amount of electric energy and no thermal energy is required, the conventional gas engine cogeneration system is forced to operate inefficiently.

  In order to avoid the situation as described above, it is conceivable to control the engine speed of the gas engine so as to generate electric energy corresponding to the required electric energy amount. However, there is a lower limit of the rotational speed for continuously supplying a stable power generation output. Therefore, when the required electric energy amount is smaller than the electric energy amount generated when the gas engine is operated at the lower limit rotation speed, the operation efficiency of the gas engine is deteriorated. Therefore, it is conceivable to reduce the load factor of the gas engine and perform partial load operation of the gas engine. However, since partial load operation of the engine is generally inefficient, it cannot be operated with high efficiency.

  The gas engine is also used for GHP (gas heat pump). The number of revolutions of the gas engine used for GHP varies according to operating conditions and air conditioning load variation. In this case as well, as in the above situation, a situation in which inefficient partial load operation is performed occurs, so that the efficiency cannot be sufficiently improved.

  The present invention relates to a gas engine control apparatus for controlling a gas engine so that the gas engine used in the gas engine cogeneration system or GHP can be operated with high efficiency and can supply the required energy. The purpose is to provide.

(Means for solving the problem)
The present invention is used in a gas engine cogeneration system that generates electric energy and heat energy, and realizes a thermodynamic cycle in which the expansion ratio and the compression ratio are equal, and the normal cycle operation and the expansion ratio are larger than the compression ratio. A control device for a gas engine that can switch an operation state to a mirror cycle operation that realizes a thermodynamic cycle, and that uses drive output for electric energy and exhaust heat for heat energy. Based on the output characteristics with respect to the rotational speed of the gas engine during mirror cycle operation, the gas engine cogeneration system can generate an electric energy amount corresponding to the required electric energy amount for the gas engine cogeneration system. Rotational speed control to control the rotational speed And the predicted thermal energy amount that the gas engine cogeneration system is expected to generate when the gas engine is operated in a mirror cycle at the rotation speed controlled by the rotation speed control section is the required thermal energy to the gas engine cogeneration system If the amount is equal to or greater than the amount, the operation state of the gas engine is Miller cycle operation, and if the predicted heat energy amount is less than the required heat energy amount, the operation state of the gas engine is normal cycle operation. An operating state control unit for controlling the gas engine is provided. In this case, the rotational speed control unit may control the rotational speed of the gas engine so that the rotational speed increases as the required electrical energy amount increases.

  According to the present invention, the rotational speed of the gas engine is controlled so that the cogeneration system can generate an electrical energy amount corresponding to the required electrical energy amount based on the rotational speed-output characteristic of the gas engine during mirror cycle operation. Is done. In addition, the operating state of the gas engine is predicted to be generated by the cogeneration system when the gas engine is operated in a mirror cycle at the rotation speed controlled by the rotation speed control unit, and the actual gas engine cogeneration is actually generated. It is controlled based on the amount of heat energy required for the generation system (the amount of required heat energy). Specifically, when the predicted heat energy amount is greater than or equal to the required heat energy amount, the gas engine operating state is set to mirror cycle operation, and when the predicted heat energy amount is less than the required heat energy amount, the gas engine operating state is normal. Cycle operation.

  That is, heat energy corresponding to the heat energy required for the cogeneration system can be supplied to the heat load by the heat energy generated when the gas engine is operated in the mirror cycle at the rotation speed controlled by the rotation speed control unit. In this case, the operation state is set to the mirror cycle operation. In this case, since the operation state is mirror cycle operation, the engine efficiency (thermal efficiency) is improved. In addition, mirror cycle operation has a smaller output than normal cycle operation, so it is possible to supply an electrical load from the cogeneration system to the electrical load that is commensurate with the small required electrical energy amount only by rotational speed control. Bad partial load operation can be avoided. On the other hand, if the heat energy corresponding to the required heat energy cannot be supplied by the heat energy generated when the gas engine is operated in the mirror cycle at the rotation speed controlled by the rotation speed control unit, the operation state is the normal cycle. To drive. In this case, since the operation state is normal cycle operation, the engine efficiency is reduced, but the amount of exhaust heat is increased, so that heat energy corresponding to the required heat energy amount is generated. That is, according to the present invention, efficient gas engine operation by performing mirror cycle operation at a rotational speed controlled according to the required amount of electrical energy and supply of sufficient thermal energy by performing normal cycle operation. Can be made compatible.

  In addition, the present invention is used for a gas heat pump, and includes a normal cycle operation that realizes a thermodynamic cycle in which an expansion ratio and a compression ratio are equal, and a mirror cycle operation that realizes a thermodynamic cycle in which the expansion ratio is larger than the compression ratio. It is a gas engine control device that can switch the operation state, and the drive output and exhaust heat are used for air-conditioning energy, and based on the output characteristics with respect to the rotation speed of the gas engine during the mirror cycle operation, The rotational speed control unit that controls the rotational speed of the gas engine so that the gas heat pump generates the air conditioning energy corresponding to the required air conditioning energy amount, and the operation state of the gas heat pump that is determined as an operation state that requires a large amount of air conditioning energy. The normal operation of the gas engine when the specified operating state is And an operation state control unit for controlling the operation state of the gas engine so that the operation state of the gas engine is a mirror cycle operation when the operation state of the gas heat pump is not the specific operation state. I will provide a. In this case, the rotational speed control unit may control the rotational speed of the gas engine so that the rotational speed increases as the required air conditioning energy amount increases.

  According to the present invention, the rotation speed of the gas engine corresponds to the required air conditioning energy (air conditioning energy required for the gas heat pump) based on the rotation speed-output characteristic of the gas engine during the mirror cycle operation. Controlled to generate air conditioning energy. Further, the operating state of the gas engine is controlled based on the operating state of the gas heat pump. Specifically, when the operating state of the gas heat pump is a specific operating state (an operating state that requires a large amount of air conditioning energy), the operating state of the gas engine is set to a normal cycle operation, and when the operating state is not the specific operating state, the gas The engine operating state is set to mirror cycle operation.

  Therefore, basically, a mirror cycle operation in which the number of revolutions is controlled according to the required air conditioning energy amount is realized, so that the gas engine can be operated efficiently. However, when the gas engine is operated in the mirror cycle, the engine efficiency is higher than in the normal cycle operation, but the drive output is reduced. For this reason, when the gas heat pump requires a large amount of air conditioning energy, there is a possibility that a driving output sufficient to generate the necessary air conditioning energy cannot be obtained even if the mirror cycle operation is performed at a controlled rotational speed. Therefore, in the present invention, when the operation state of the gas heat pump is a specific operation state (an operation state that requires large air-conditioning energy), the operation state is set to a normal cycle operation. As a result, the drive output increases and the amount of exhaust heat also increases, and a drive output sufficient to produce the required air conditioning energy can be obtained. That is, according to the present invention, efficient gas engine operation by performing mirror cycle operation at a rotational speed controlled according to the required air conditioning energy amount and normal cycle operation when in a specific operation state It is possible to achieve both sufficient air conditioning energy supply.

  The specific operation state includes an initial operation state within a predetermined time after the operation of the gas heat pump is started, and a low temperature heating operation in which the gas heat pump performs a heating operation when the outside air temperature is equal to or lower than a predetermined temperature. It is good that it is either a state and the defrost operation state in which a gas heat pump performs a defrost operation. When the operation state of the gas heat pump is one of the above-described operation states, sufficient air-conditioning energy cannot be obtained even if the gas engine is operated in a mirror cycle. Therefore, necessary air-conditioning energy can be obtained by operating the gas engine in a normal cycle at such times.

1 is an overall view of a gas engine cogeneration system 1 that uses a gas engine of a first embodiment. It is the schematic which shows the structure of the cam shaft vicinity in the gas engine of 1st Embodiment. It is the schematic which shows the structure of the cam shaft vicinity in the gas engine of 1st Embodiment. It is a graph which shows the change of the lift amount of the exhaust valve and intake valve of the gas engine of 1st Embodiment. It is a figure which shows the structure of an engine control apparatus. It is a flowchart which shows the rotation speed control routine which the rotation speed control part which concerns on 1st Embodiment performs. It is a characteristic line figure of drive output to number of rotations at the time of carrying out mirror cycle operation of the gas engine concerning a 1st embodiment. It is a flowchart which shows the driving | running state control routine which the driving | running state control part which concerns on 1st Embodiment performs. It is the schematic which shows the structure of the cam shaft vicinity in the gas engine of 2nd Embodiment. It is a graph which shows the change of the lift amount of the exhaust valve and intake valve of the gas engine of 2nd Embodiment. It is a flowchart which shows the driving | running state control routine which the driving | running state control part which concerns on 2nd Embodiment performs. It is the schematic which shows the whole structure of GHP (gas heat pump) which concerns on 3rd Embodiment. It is a flowchart which shows the rotation speed control routine which the rotation speed control part which concerns on 3rd Embodiment performs. It is a characteristic line figure of drive output to number of rotations at the time of carrying out mirror cycle operation of the gas engine concerning a 3rd embodiment. It is a flowchart which shows the driving | running state control routine which the driving | running state control part which concerns on 3rd Embodiment performs.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is an overall view of a gas engine cogeneration system 1 that uses a gas engine according to the present embodiment. The gas engine cogeneration system 1 is installed in, for example, a home, a restaurant, or a welfare facility, and generates electric energy and thermal energy by driving the gas engine. And the produced | generated electric energy and heat energy are supplied to an electric utilization apparatus (electric load) and a heat utilization apparatus (heat load). As shown in FIG. 1, the gas engine cogeneration system 1 includes a cogeneration unit 10, an exhaust heat recovery unit 20, and an engine control device 30.

  The cogeneration unit 10 includes a gas engine 11, a generator 12, an inverter 13, an engine coolant circuit 14, a pump 15, and an engine exhaust heat exchanger 16.

  The gas engine 11 is a single cylinder small engine. For example, propane gas can be used as the fuel gas. A rotation speed sensor 11 a is attached to the gas engine 11. The rotational speed sensor 11 a detects the engine rotational speed R of the gas engine 11 and outputs information representing the detected engine rotational speed R to the engine control device 30.

  The generator 12 is connected to the output shaft of the gas engine 11 and is configured to operate by driving the gas engine 11 to generate power. The DC power (electric energy) generated by the generator 12 is converted into AC by the inverter 13.

  The electric power converted from direct current to alternating current by the inverter 13 is supplied to a distribution board 41 in the home, for example. The distribution board 41 is also supplied with AC power from a commercial power source. Electric power is supplied from the distribution board 41 to each of the electricity utilization devices (electric loads) E1 to E6. The electric current flowing through the electrical wiring connecting the inverter 13 and the distribution board 41 is detected by the power measuring instrument 42. The power meter 42 calculates an electric energy amount (required electric energy amount) E required for the gas engine cogeneration system 1 from the detected current, and performs engine control on information indicating the calculated required electric energy amount E. Output to device 30.

  The engine coolant circuit 14 is constituted by a pipe filled with coolant. The engine coolant circuit 14 is connected to a coolant passage formed in the gas engine 11. A pump 15 and an engine exhaust heat exchanger 16 are connected to the engine coolant circuit 14. When the pump 15 is driven, the coolant in the engine coolant circuit 14 passes through the gas engine 11 to cool the gas engine 11 and absorbs the heat of the exhaust gas discharged from the gas engine 11. Cooling water that has cooled the gas engine 11 and absorbed the heat of the exhaust gas and heated is introduced into the engine exhaust heat exchanger 16, and in the exhaust heat recovery circuit 23, which will be described later, in the engine exhaust heat exchanger 16. Gives heat to the flowing refrigerant.

  The exhaust heat recovery unit 20 includes a hot water tank 21, a hot water supply device 22, and an exhaust heat recovery circuit 23. Water such as tap water is supplied into the hot water tank 21. The exhaust heat recovery circuit 23 includes a pipe filled with a refrigerant. The exhaust heat recovery circuit 23 is connected to the engine exhaust heat exchanger 16 in the cogeneration unit 10, and a part thereof passes through the hot water tank 21. A pump 24 is connected to the exhaust heat recovery circuit 23. When the pump 24 is driven, the refrigerant flows through the exhaust heat recovery circuit 23 and is introduced into the engine exhaust heat exchanger 16. In the engine exhaust heat exchanger 16, as described above, the heat from the cooling water that has cooled and heated the gas engine 11 is transferred to the refrigerant in the exhaust heat recovery circuit 23. Thereby, the refrigerant is heated. The refrigerant thus heated flows through the exhaust heat recovery circuit 23 and passes through the hot water tank 21, whereby the water in the hot water tank 21 is heated. In this way, thermal energy is generated by recovering the exhaust heat of the gas engine 11.

  The hot water tank 21 is connected to a hot water supply device 22. The hot water supply device 22 is connected to a domestic heat utilization device H1 (for example, a floor heating device) via a pipe or the like. Accordingly, the hot water in the hot water tank 21 is supplied to the heat utilization device H1 in the home via the hot water supply device 22. The hot water supply device 22 may be a water heater, for example. Further, the hot water supply device 22 calculates a thermal energy amount (required thermal energy amount) H required for the gas engine cogeneration system 1 from the domestic heat utilization device H1, and the magnitude of the calculated required thermal energy amount H. Is output to the engine control device 30.

  By the way, the gas engine 11 in the cogeneration unit 10 is configured such that its operation state can be switched between a normal cycle operation and a mirror cycle operation. “Normal cycle operation” is an operation state that realizes a thermodynamic cycle in which the expansion ratio and compression ratio are equal. “Mirror cycle operation” is a thermodynamic cycle in which the expansion ratio is larger than the compression ratio. It is the driving state which realizes. In the present embodiment, the gas engine 11 is configured such that the opening / closing timing of the intake valve in the gas engine 11 is different between the normal cycle operation and the mirror cycle operation. Therefore, a cam (normal cam) used for lifting the intake valve during normal cycle operation and a cam (mirror cam) used for lifting the intake valve during mirror cycle operation are required. Further, a switching mechanism for switching these cams is necessary.

  2 and 3 are schematic views showing a configuration in the vicinity of the camshaft in the gas engine 11. As shown in FIGS. 2 and 3, a camshaft 81 is rotatably disposed in the gas engine 11. The camshaft 81 rotates in conjunction with the rotation of the output shaft of the gas engine 11. A cam unit 82 is attached to the camshaft 81. The cam unit 82 includes an intake mirror cam 83, an intake normal cam 84, and an exhaust cam 85, and these cams are provided so as to be aligned along the axial direction of the camshaft 81. These cams 83, 84, 85 rotate integrally with the camshaft 81. A rocker shaft 86 is disposed in the gas engine 11 in parallel with the camshaft 81. A first roller rocker arm 871, a second roller rocker arm 872, and a third roller rocker arm 873 are swingably attached to the rocker shaft 86. These roller rocker arms 871, 872, and 873 are provided so as to be aligned along the axial direction of the rocker shaft 86. The roller R1 of the first roller rocker arm 871 contacts the cam surface of the intake mirror cam 83, the roller R2 of the second roller rocker arm 872 contacts the cam surface of the intake normal cam 84, and the third roller rocker arm. Each roller rocker arm is attached to the rocker shaft 86 so that the roller 873 of the 873 is in contact with the cam surface of the exhaust cam 85.

  An intake push rod 88 is attached to the first roller rocker arm 871, and an exhaust push rod 89 is attached to the third roller rocker arm 873. The intake valve 90 in the gas engine 11 operates in conjunction with the operation of the intake push rod 88, and the exhaust valve 91 in the gas engine 11 operates in conjunction with the operation of the exhaust push rod 89.

  The first roller rocker arm 871 and the second roller rocker arm 872 are formed with holes that are opened on the opposite side surfaces so as to face each other. Accordingly, a passage 876 extending in the axial direction of the camshaft 81 is formed by these holes. A pin 877 serving as a switching mechanism is inserted into the passage 876.

  The pin 877 is configured to change its position in the passage 876 in response to an oil pressure from a hydraulic circuit (not shown). Specifically, the pin 877 has a hole in the first roller rocker arm 871 and a second roller rocker arm 872 so as to straddle the first roller rocker arm 871 and the second roller rocker arm 872 as shown in FIG. As shown in FIG. 3, all the pins 877 are inserted into the holes in the first roller rocker arm 871 and the holes in the second roller rocker arm 872 It can be displaced to a position where it is not inserted (mirror position).

  In the present embodiment, the intake valve 90 operates according to the cam profile of either the intake mirror cam 83 or the intake normal cam 84, and the exhaust valve 91 operates according to the cam profile of the exhaust cam 85. FIG. 4 is a graph showing changes in the lift amounts of the exhaust valve 91 and the intake valve 90 of the gas engine 11 according to the present embodiment. The horizontal axis in FIG. 4 is the crank angle, and the vertical axis is the lift amount. Curve A represents a change in the lift amount of the exhaust valve 91 when the exhaust valve 91 is operated in accordance with the cam profile of the exhaust cam 85. A curve B represents a change in the lift amount (normal profile) of the intake valve 90 when the intake valve 90 is operated according to the cam profile of the normal cam 84 for intake. A curve C represents a change in the lift amount (mirror profile) of the intake valve 90 when the intake valve 90 is operated according to the cam profile of the intake mirror cam 83.

  As shown in FIG. 4, when the intake valve 90 is operated according to the cam profile of the intake mirror cam 83, the valve opening time is shorter than when the intake valve 90 is operated according to the cam profile of the intake normal cam 84. That is, when the intake mirror cam 83 is used, the intake valve 90 closes earlier than when the intake normal cam 84 is used. Therefore, the compression stroke in the combustion chamber is shortened. Thereby, a mirror cycle in which the expansion ratio is larger than the compression ratio is realized. On the other hand, when the intake normal cam 84 is used, the compression ratio in the compression stroke and the expansion ratio in the expansion stroke are made substantially equal. As a result, a normal cycle in which the compression ratio and the expansion ratio are substantially equal is realized.

  As can be seen from FIG. 4, the mirror profile is included in the normal profile. That is, the lift amount of the intake valve 90 represented by the mirror profile is always smaller than the lift amount of the intake valve 90 represented by the normal profile.

  Here, the first roller rocker arm 871 receives an operating force accompanying the rotation of the intake mirror cam 83, and the second roller rocker arm 872 receives an operating force accompanying the rotation of the intake normal cam 84. As shown, when the pin 877 is in the normal position, the first roller rocker arm 871 is connected to the second roller rocker arm 872 via the pin 877. Therefore, the first roller rocker arm 871 operates in conjunction with the second roller rocker arm 872. That is, the first roller rocker arm 871 also receives an operating force accompanying the rotation of the intake normal cam 84. As described above, since the mirror profile is included in the normal profile, when the pin 877 is in the normal position, the normal profile is eventually given priority. The first roller rocker arm 871 and the intake push rod 88 are swung by the operating force accompanying the rotation of the intake normal cam 84. That is, when the pin 877 is in the normal position, the connection state between the intake valve 90 and the cam unit 82 is a normal connection state in which the intake valve 90 operates according to the cam profile of the intake normal cam 84. For this reason, the operation state of the gas engine is set to the normal cycle operation.

  On the other hand, when the pin 877 is in the mirror position as shown in FIG. 3, the first roller rocker arm 871 and the second roller rocker arm 872 operate separately. Accordingly, the first roller rocker arm 871 and the intake push rod 88 are swung by the operating force accompanying the rotation of the intake mirror cam 83. That is, when the pin 877 is in the mirror position, the connection state between the intake valve 90 and the cam unit 82 is a mirror connection state in which the intake valve 90 operates according to the cam profile of the intake mirror cam 83. For this reason, the operation state of the gas engine is set to the mirror cycle operation.

  As described above, the pin 877 operates so that the connection state between the intake valve 90 and the cam unit 82 can be switched between the normal connection state and the mirror connection state. The operation state of the gas engine 11 according to the present embodiment is configured to be switched between the normal cycle operation and the mirror cycle operation by switching the position of the pin 877 between the normal position and the mirror position. The engine control device 30 controls the position of the pin 877, that is, the connection state between the intake valve 90 and the cam unit 82, that is, the operation state of the gas engine 11.

  The engine control device 30 is configured by a microcomputer including a CPU, ROM, RAM, and the like. As described above, the information indicating the required electrical energy amount E is input from the power measuring device 42 to the engine control device 30, and the information indicating the engine speed R of the gas engine 11 is input from the speed sensor 11a. Information indicating the magnitude of the heat energy amount H is input from the hot water supply device 22. The engine control device 30 controls the engine speed and operating state of the gas engine 11 based on the input information. FIG. 5 is a block diagram showing only the part related to the present embodiment among the functions of the engine control device 30. As shown in FIG. 5, the engine control device 30 includes a rotation speed control unit 31 and an operation state control unit 32. The rotation speed control unit 31 controls the engine rotation speed of the gas engine 11. The operation state control unit 32 controls the operation state of the gas engine 11, specifically, switching between normal cycle operation and mirror cycle operation (that is, switching of the position of the pin 877).

  In the gas engine cogeneration system 1 having the above-described configuration, as described above, when the gas engine 11 is driven, the generator 12 generates electric power along with it, and the electric energy generated by the generator 12 is used in the household electric appliance E1. To E6. Further, the heat energy generated by recovering the heat generated by driving the gas engine 11 is supplied as hot water to a heat utilization device (heat load) H1 in the home.

  While the gas engine 11 is being driven, the rotation speed control unit 31 of the engine control device 30 executes a rotation speed control routine. FIG. 6 is a flowchart showing a rotation speed control routine executed by the rotation speed control unit 31. When the rotation speed control routine is activated, the rotation speed control unit 31 first reads out the required electrical energy amount E input from the power measuring instrument 42 in step 11 of FIG. 6 (hereinafter, step is abbreviated as S). Next, a driving output (necessary driving output) T of the gas engine 11 required for the generator 12 to generate an electric energy amount corresponding to the required electric energy amount E is calculated (S12). Subsequently, the rotation speed control unit 31 refers to the characteristic diagram of the drive output with respect to the rotation speed when the gas engine 11 is operated in the mirror cycle, and determines the engine rotation speed corresponding to the required drive output T as the required rotation speed Rr. (S13).

  FIG. 7 is a characteristic diagram of the drive output with respect to the rotation speed when the gas engine 11 is operated in a mirror cycle. As shown in FIG. 7, as the rotational speed increases, the drive output also increases. The rotational speed control unit 31 calculates the required rotational speed Rr corresponding to the necessary drive output T with reference to such a characteristic diagram.

  After calculating the required rotational speed Rr in S13, the rotational speed control unit 31 outputs the calculated required rotational speed Rr to the gas engine 11 (S14). Thus, the engine speed of the gas engine 11 is controlled so that the engine speed of the gas engine 11 matches the required speed Rr. Thereafter, the rotation speed control unit 31 ends this routine.

  As described above, the rotation speed control unit 31 executes the rotation speed control routine, so that the engine rotation speed of the gas engine 11 is set according to the amount of electric energy E required for the gas engine cogeneration system 1. Change. Specifically, the engine speed of the gas engine 11 is controlled so that the engine speed decreases as the required electrical energy amount E decreases. Therefore, a power generation amount commensurate with the required electric energy amount E can be obtained, and useless power generation can be suppressed. For this reason, engine efficiency can be improved.

  Further, while the gas engine 11 is being driven, the operation state control unit 32 of the engine control device 30 executes an operation state control routine. FIG. 8 is a flowchart showing an operation state control routine executed by the operation state control unit 32. When the operation state control routine is activated, the operation state control unit 32 first determines in S21 of FIG. 8 whether or not the elapsed time t is greater than the reference time t0. Here, the elapsed time t is an elapsed time since the gas engine 11 was started. The reference time t0 is determined in advance as a time required for the gas engine 11 to start and stabilize.

  When the elapsed time t is equal to or less than the reference time t0 (S21: No), that is, when the gas engine 11 is in the initial stage of starting and is not sufficiently warmed (not stable), the operating state control unit 32 performs S26. Proceed with the process. In S <b> 26, a normal operation signal is output to the gas engine 11. Accordingly, the position of the pin 877 is controlled so that the pin 877 in the gas engine 11 is positioned at the normal position. For this reason, the operation state of the gas engine 11 is set to the normal cycle operation. Thereafter, the operating state control unit 32 ends this routine.

  When the elapsed time t is greater than the reference time t0 (S21: Yes), that is, when the gas engine 11 has already been sufficiently warmed (stable), the operating state control unit 32 advances the process to S22. . In S <b> 22, the operation state control unit 32 reads the required heat energy amount H input from the hot water supply device 22. Next, the operating state control unit 32 calculates a predicted heat energy amount H1 (S23). The predicted heat energy amount is a predicted value of the heat energy amount generated by the cogeneration system 1 when the gas engine 11 is operated in a mirror cycle at the engine speed controlled by the rotation speed control unit 31. . The calculation of the predicted heat energy amount H1 can be performed, for example, by investigating the relationship between the rotational speed of the gas engine 11 that is operating in the mirror cycle and the exhaust heat amount in advance, and based on the investigation result.

  After calculating the predicted heat energy amount H1 in S23, the operation state control unit 32 determines whether or not the predicted heat energy amount H1 is larger than the required heat energy amount H (S24). When it is determined that the predicted heat energy amount H1 is equal to or greater than the required heat energy amount H (S24: Yes), the operation state control unit 32 advances the process to S25. In S25, a mirror operation signal is output to the gas engine 11. Accordingly, the position of the pin 877 is controlled so that the pin 877 in the gas engine 11 is positioned at the mirror position. For this reason, the operation state of the gas engine 11 is set to the mirror cycle operation. Thereafter, the operating state control unit 32 ends this routine.

  In S24, when it is determined that the predicted heat energy amount H1 is less than the required heat energy amount H (S24: No), the operation state control unit 32 advances the process to S26. In S <b> 26, a normal operation signal is output to the gas engine 11. Accordingly, the position of the pin 877 is controlled so that the pin 877 in the gas engine 11 is positioned at the normal position. For this reason, the operation state of the gas engine 11 is set to the normal cycle operation. Thereafter, the operating state control unit 32 ends this routine.

  As a result of the above-described control being performed by the rotational speed control unit 31 and the operating state control unit 32, the engine rotational speed is controlled so that the engine rotational speed R decreases as the required electrical energy amount E decreases, and the predicted thermal energy amount. When H1 is greater than or equal to the required heat energy amount H, the gas engine 11 is operated in a mirror cycle, and when the predicted heat energy amount H1 is less than the required heat energy amount H, the gas engine 11 is operated in a normal cycle.

  That is, the heat energy generated when the engine control device 30 controls the gas engine 11 as described above to cause the gas engine 11 to perform a mirror cycle operation at the rotation speed controlled by the rotation speed control unit 31. If the heat energy corresponding to the heat energy required for the cogeneration system 1 can be supplied, the operation state is set to the mirror cycle operation. In this case, since the operation state is the mirror cycle operation, the engine efficiency is improved. On the other hand, when the heat energy corresponding to the required heat energy cannot be supplied by the heat energy generated when the gas engine 11 is operated in the mirror cycle at the rotation speed controlled by the rotation speed control unit 31, the operation state is Normal cycle operation is performed. In this case, since the operation state is normal cycle operation, the engine efficiency is reduced, but the amount of exhaust heat is increased, so that heat energy corresponding to the required heat energy amount is generated. That is, according to this embodiment, sufficient heat energy by performing efficient operation of the gas engine 11 by performing mirror cycle operation at a rotational speed controlled according to the required amount of electric energy and performing normal cycle operation. Can be made compatible with the supply of

(Second Embodiment)
In the first embodiment, the example in which one intake mirror cam 83 is provided in the gas engine 11 has been described. However, a plurality of (for example, three) intake mirror cams are provided in the gas engine 11 to rotate the engine. Depending on the number, one intake mirror cam may be selected from among a plurality of intake mirror cams, and the gas engine 11 may be operated in a mirror cycle using the selected intake mirror cam. In this case, the configuration in the vicinity of the camshaft in the gas engine 11 may be as shown in FIG. According to FIG. 9, the cam unit 82 attached to the camshaft 81 disposed in the gas engine 11 includes the intake first mirror cam 831, the intake second mirror cam 832, the intake third mirror cam 833, and the intake air. A normal cam 84 and an exhaust cam 85 are provided, and these cams are provided in this order along the axial direction of the camshaft 81. These cams 831, 832, 833, 84, and 85 rotate integrally with the camshaft 81. The intake valve 90 operates in accordance with any one of the intake cams 831, 832, 833, and 834, and the exhaust valve 91 operates in accordance with the cam profile of the exhaust cam 85.

  Further, a rocker shaft 86 disposed in the gas engine 11 in parallel with the camshaft 81 is provided with a first roller rocker arm 871, a second roller rocker arm 872, a third roller rocker arm 873, a fourth roller rocker arm 874, A fifth roller rocker arm 875 is swingably attached. These roller rocker arms 871, 872, 873, 874, and 875 are provided so as to be arranged in this order along the axial direction of the rocker shaft 86. The roller R1 of the first roller rocker arm 871 comes into contact with the cam surface of the first mirror cam 831 for intake, the roller R2 of the second roller rocker arm 872 comes into contact with the cam surface of the second mirror cam 832 for intake, and the third The roller R3 of the roller rocker arm 873 comes into contact with the cam surface of the third mirror cam 833 for intake, the roller R4 of the fourth roller rocker arm 874 comes into contact with the cam surface of the normal cam 84 for intake, and the fifth roller rocker arm Each roller rocker arm is attached to the rocker shaft 86 so that the 875 roller R5 comes into contact with the cam surface of the exhaust cam 85.

  An intake push rod 88 is attached to the first roller rocker arm 871, and an exhaust push rod 89 is attached to the fifth roller rocker arm 875. The intake valve 90 in the gas engine 11 operates in conjunction with the operation of the intake push rod 88, and the exhaust valve 91 in the gas engine 11 operates in conjunction with the operation of the exhaust push rod 89.

  A through hole is formed in the first roller rocker arm 871, the second roller rocker arm 872, and the third roller rocker arm 873, and a bottomed hole is formed in the fourth roller rocker arm 874. These holes are opened on the respective opposing side surfaces of the respective roller rocker arms 871, 872, 873, and 874 so as to face the adjacent roller rocker arms. Moreover, the center axis directions of these holes coincide. Accordingly, a passage 876 extending in the axial direction of the camshaft 81 is formed by these holes. A pin 877 serving as a switching mechanism is inserted into the passage 876.

  The pin 877 is configured to change its position in the passage 876 in response to an oil pressure from a hydraulic circuit (not shown). Specifically, the pin 877 is configured to be displaceable to a normal position, a third mirror position, a second mirror position, and a first mirror position. The normal position is a hole formed in these roller rocker arms 871, 872, 873, 874 such that the pin 877 straddles the first, second, third, fourth roller rocker arms 871, 872, 873, 874. This is the position where the pin 877 is inserted into all of the above. The third mirror position is inserted through holes formed in these roller rocker arms 871, 872, 873 so that the pin 877 straddles the first, second and third roller rocker arms 871, 872, 873, This is a position where the pin 877 is not inserted into the hole formed in the four-roller rocker arm 874. The second mirror position is inserted into holes formed in these roller rocker arms 871 and 872 so that the pin 877 straddles the first and second roller rocker arms 871 and 872, and the third and fourth roller rocker arms It is a position where the pin 877 is not inserted into the hole formed in 873,874. In the first mirror position, the pin 877 is inserted only into the hole formed in the first roller rocker arm 871, and is inserted into the hole formed in the second, third and fourth roller rocker arms 872, 873, 874. It is not a position. The case where the pin 877 is in the normal position is shown in FIG. 9A, the case where the pin 877 is in the third mirror position is shown in FIG. 9B, and the case where the pin 877 is in the second mirror position. 9 (c), and the case where the pin 877 is at the first mirror position is shown in FIG. 9 (d).

  FIG. 10 is a graph showing changes in the lift amounts of the exhaust valve 91 and the intake valve 90 of the gas engine 11 according to the present embodiment. The horizontal axis in FIG. 10 is the crank angle, and the vertical axis is the lift amount. Curve A represents a change in the lift amount of the exhaust valve 91 when the exhaust valve 91 is operated in accordance with the cam profile of the exhaust cam 85. A curve B represents a change in the lift amount (normal profile) of the intake valve 90 when the intake valve 90 is operated according to the cam profile of the normal cam 84 for intake. A curve C represents a change in the lift amount of the intake valve 90 (third mirror profile) when the intake valve 90 is operated according to the cam profile of the intake third mirror cam 833. A curve D represents a change in the lift amount of the intake valve 90 (second mirror profile) when the intake valve 90 is operated according to the cam profile of the intake second mirror cam 832. A curve E represents a change in the lift amount of the intake valve 90 (first mirror profile) when the intake valve 90 is operated according to the cam profile of the intake first mirror cam 831.

  As shown in FIG. 10, regarding the operation of the intake valve 90, when the intake valve 90 is operated according to the cam profile of the intake first mirror cam 831 (curve E), the opening time of the intake valve 90 is the shortest (that is, the earliest). close up). When the intake valve 90 is operated according to the cam profile of the intake second mirror cam 832 (curve D), the valve opening time of the intake valve 90 is the next shortest (and then closed earlier), and according to the cam profile of the intake third mirror cam 833 When the intake valve 90 is activated, the opening time of the intake valve 90 is the next shortest (and then closes earlier). When the intake valve 90 is operated according to the cam profile of the normal intake cam 84, the valve opening time of the intake valve 90 is the longest (closed latest). In this case, the compression ratio in the compression stroke is substantially equal to the expansion ratio in the expansion stroke. Therefore, by driving the gas engine 11 using the intake normal cam 84, a normal cycle operation in which the compression ratio and the expansion ratio are substantially equal is realized. By driving the gas engine 11 using other intake cams, mirror cycle operation in which the expansion ratio is larger than the compression ratio is realized.

  As can be seen from FIG. 10, the third mirror profile (curve C) is included in the normal profile (curve B), the second mirror profile (curve D) is included in the third mirror profile (curve C), One mirror profile (curve E) is included in the second mirror profile (curve D). That is, the lift amount of the intake valve 90 represented by the third mirror profile is always smaller than the lift amount of the intake valve 90 represented by the normal profile, and the lift amount of the intake valve 90 represented by the second mirror profile is the third mirror profile. The lift amount of the intake valve 90 represented by the first mirror profile is always smaller than the lift amount of the intake valve 90 represented by the second mirror profile.

  Here, the first roller rocker arm 871 connected to the intake valve 90 via the intake push rod 88 receives an operating force accompanying the rotation of the intake first mirror cam 831. The second roller rocker arm 872 receives an operating force accompanying the rotation of the intake second mirror cam 832, and the third roller rocker arm 873 receives an operating force accompanying the rotation of the intake third mirror cam 833, and receives the fourth roller rocker arm 873. The arm 874 receives an operating force accompanying the rotation of the intake normal cam 84. At this time, as shown in FIG. 9A, when the pin 877 is in the normal position, the first, second, third, and fourth roller rocker arms 871, 872, 873, and 874 are connected via the pin 877. . The cam having the largest cam profile among the cams for operating the connected roller rocker arms is the intake normal cam 84. Therefore, when the pin 877 is in the normal position, the first roller rocker arm 871 operates in accordance with the normal profile, and accordingly, the intake valve 90 connected to the first roller rocker arm 871 via the intake push rod 88 is also included. Works according to the normal profile. That is, when the pin 877 is in the normal position, the connection state between the intake valve 90 and the cam unit 82 is a mirror connection state in which the intake valve 90 operates according to the cam profile of the intake normal cam 84, and the operation of the gas engine 11 is performed. The state is set to normal cycle operation.

  9B, when the pin 877 is at the third mirror position, the first, second, and third roller rocker arms 871, 872, and 873 are connected via the pin 877. The cam having the largest cam profile among the cams for operating the connected roller rocker arms is the third mirror cam 833. Therefore, when the pin 877 is at the third mirror position, the first roller rocker arm 871 operates according to the third mirror profile, and accordingly, the intake valve 90 connected to the first roller rocker arm 871 also follows the third mirror profile. Operate. That is, when the pin 877 is at the third mirror position, the connection state between the intake valve 90 and the cam unit 82 is the third mirror connection state in which the intake valve 90 operates according to the cam profile of the intake third mirror cam 833, The operation state of the gas engine 11 is set to the mirror cycle operation (third mirror cycle operation) using the third mirror cam 833.

  9C, when the pin 877 is at the second mirror position, the first and second roller rocker arms 871 and 872 are connected via the pin 877. The cam having the largest cam profile among the cams for operating the connected roller rocker arms is the second mirror cam 832. Accordingly, when the pin 877 is at the second mirror position, the first roller rocker arm 871 operates according to the second mirror profile, and accordingly, the intake valve 90 connected to the first roller rocker arm 871 also follows the second mirror profile. Operate. That is, when the pin 877 is in the second mirror position, the connection state between the intake valve 90 and the cam unit 82 is the second mirror connection state in which the intake valve 90 operates according to the cam profile of the intake second mirror cam 832. The operation state of the gas engine 11 is set to the mirror cycle operation (second mirror cycle operation) using the second mirror cam 832.

  Further, as shown in FIG. 9D, when the pin 877 is at the first mirror position, the first roller rocker arm 871 operates alone. Therefore, when the pin 877 is at the first mirror position, the first roller rocker arm 871 is operated according to the cam profile (first mirror profile) of the first mirror cam 831 and is connected to the first roller rocker arm 871 accordingly. The intake valve 90 also operates according to the first mirror profile. That is, when the pin 877 is at the first mirror position, the connection state between the intake valve 90 and the cam unit 82 is the first mirror connection state in which the intake valve 90 is operated according to the cam profile of the intake first mirror cam 831. The operation state of the gas engine 11 is set to the mirror cycle operation (first mirror cycle operation) using the first mirror cam 831.

  As described above, the pin 877 operates so that the connection state between the intake valve 90 and the cam unit 82 can be switched between the normal connection state and the plurality of mirror connection states. The operating state of the gas engine 11 according to this embodiment is switched to either the normal cycle operation or the plurality of mirror cycle operations by switching the position of the pin 877 to either the normal position or the plurality of mirror positions. It is configured to be able to. The engine control device 30 controls the position of the pin 877, that is, the connection state between the intake valve 90 and the cam unit 82, that is, the operation state of the gas engine 11.

  When the gas engine having the structure shown in FIG. 9 is used, the rotation speed control unit 31 of the engine control device 30 performs the same process as the process shown in the flowchart shown in FIG. To control. In this case, the rotation speed control unit 31 refers to the characteristic diagram of the drive output with respect to the rotation speed when the first mirror cycle operation with the highest efficiency is performed in calculating the required rotation speed Rr in S13.

  Moreover, when using the gas engine which has a structure shown in FIG. 9, the driving | running state control part 32 of the engine control apparatus 30 performs the driving | running state control routine shown in FIG. When the operation state control routine shown in FIG. 11 is started, the operation state control unit 32 first determines whether or not the elapsed time t is larger than the reference time t0 in S31 of FIG. When the elapsed time t is equal to or less than the reference time t0 (S31: No), that is, when the gas engine 11 is in the initial stage of starting and is not sufficiently warmed (not stable), the operation state control unit 32 performs S42. Proceed with the process. In S <b> 42, a normal operation signal is output to the gas engine 11. Accordingly, the position of the pin 877 is controlled so that the pin 877 in the gas engine 11 is positioned at the normal position. For this reason, the operating state of the gas engine 11 is set to the normal operating state. Thereafter, the operating state control unit 32 ends this routine.

  On the other hand, when the elapsed time t is greater than the reference time t0 (S31: Yes), that is, when the gas engine 11 is already sufficiently warmed (stable), the operation state control unit 32 advances the process to S32. . In S <b> 32, the operation state control unit 32 reads out the required heat energy amount H input from the hot water supply device 22. Next, a first predicted heat energy amount H1 is calculated (S33). The first predicted thermal energy amount H1 is a predicted value of the thermal energy amount generated by the cogeneration system 1 when the gas engine 11 is operated in the first mirror cycle at the engine speed controlled by the rotational speed control unit 31. It is. Subsequently, the operation state control unit 32 calculates the second predicted heat energy amount H2 (S34). The second predicted thermal energy amount H2 is a predicted value of the thermal energy amount generated by the cogeneration system 1 when the gas engine 11 is operated in the second mirror cycle at the engine speed controlled by the rotational speed control unit 31. It is. Next, the operation state control unit 32 calculates a third predicted heat energy amount H3 (S35). The third predicted thermal energy amount H3 is a predicted value of the thermal energy amount generated by the cogeneration system 1 when the gas engine 11 is operated in the third mirror cycle at the engine speed controlled by the rotational speed control unit 31. It is. The first predicted thermal energy amount H1 is smaller than the second predicted thermal energy amount H2, and the second predicted thermal energy amount H2 is smaller than the third thermal energy amount H3.

  After calculating each predicted heat energy amount H1, H2, H3, the operation state control unit 32 advances the process to S36. In S36, the operation state control unit 32 determines whether or not the first predicted thermal energy amount H1 is equal to or greater than the required thermal energy amount. When the first predicted heat energy amount H1 is equal to or greater than the required heat energy amount (S36: Yes), the operation state control unit 32 outputs a first mirror operation signal (S39). Thereby, the pin 877 in the gas engine 11 is positioned at the first mirror position, and the operation state of the gas engine 11 is set to the first mirror cycle operation. After outputting the first mirror operation signal, the operation state control unit 32 ends this routine.

  When it is determined in S36 that the first predicted heat energy amount H1 is less than the required heat energy amount H (S36: No), the operation state control unit 32 advances the process to S37. In S37, the operation state control unit 32 determines whether or not the second predicted thermal energy amount H2 is equal to or greater than the required thermal energy amount H. When the second predicted heat energy amount H2 is equal to or greater than the required heat energy amount H (S37: Yes), the operation state control unit 32 outputs a second mirror operation signal (S40). Thereby, the pin 877 in the gas engine 11 is positioned at the second mirror position, and the operation state of the gas engine 11 is set to the second mirror cycle operation. After outputting the second mirror operation signal, the operation state control unit 32 ends this routine.

  When it is determined in S37 that the second predicted heat energy amount H2 is less than the required heat energy amount H (S37: No), the operation state control unit 32 advances the process to S38. In S38, the operation state control unit 32 determines whether or not the third predicted heat energy amount H3 is equal to or greater than the required heat energy amount H. When the third predicted heat energy amount H3 is equal to or greater than the required heat energy amount H (S38: Yes), the operation state control unit 32 outputs a third mirror operation signal (S41). Thereby, the pin 877 in the gas engine 11 is positioned at the first mirror position, and the operation state of the gas engine 11 is set to the first mirror cycle operation. After outputting the first mirror operation signal, the operation state control unit 32 ends this routine.

  When it is determined in S38 that the third predicted heat energy amount H3 is less than the required heat energy amount H (S38: No), the operation state control unit 32 proceeds to S42 and outputs a normal operation signal to the gas engine 11. . Accordingly, the position of the pin 877 is controlled so that the pin 877 in the gas engine 11 is positioned at the normal position. For this reason, the operating state of the gas engine 11 is set to the normal operating state. Thereafter, the operating state control unit 32 ends this routine.

  When the required thermal energy amount H is equal to or less than the third predicted thermal energy amount H3, the operating state control unit 32 executes the above-described operating state control routine. The operating state changes to cycle operation, second mirror cycle operation, and third mirror cycle operation. Specifically, the gas engine is operated in a mirror cycle by using a mirror cam in which the expansion ratio with respect to the compression ratio increases as the required heat energy amount H decreases. Therefore, the gas engine 11 can be operated in a mirror cycle so that the engine efficiency is maximized while supplying the heat energy corresponding to the required heat energy amount.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In this embodiment, a control device for a gas engine used for GHP will be described. FIG. 12 is a schematic diagram showing the overall configuration of GHP2. The GHP 2 performs air conditioning by circulating the refrigerant in the refrigerant circuit by driving the gas engine. As shown in FIG. 12, the GHP 2 includes a gas engine 51, a compressor 52, a refrigerant pipe 53, an indoor heat exchanger 54, an outdoor heat exchanger 55, an expansion valve 56, a four-way switching valve 57, and an accumulator. 58, an indoor remote controller 59, and an engine control device 30. The indoor heat exchanger 54, the outdoor heat exchanger 55, the expansion valve 56, and the four-way switching valve 57 are interposed in the refrigerant pipe 53. The refrigerant flows through the refrigerant pipe 53.

  The gas engine 51 is driven by supplying fuel gas. The drive output and exhaust heat of the gas engine 51 are used for generating air conditioning energy by GHP. The compressor 52 has an input shaft connected to the output shaft of the gas engine 51 so that power can be transmitted, and is driven by the driving force of the gas engine 51. The compressor 52 has a discharge port 521 and a suction port 522. One end of the refrigerant pipe 53 is connected to the suction port 522, and the other end of the refrigerant pipe 53 is connected to the discharge port 521. When the compressor 52 is driven, the low-pressure gas refrigerant in the refrigerant pipe 53 is sucked from the suction port 522, the sucked low-pressure gas refrigerant is compressed inside, and the compressed high-pressure gas refrigerant is discharged from the discharge port 521 to the refrigerant pipe 53. To do.

  The indoor heat exchanger 54 and the outdoor heat exchanger 55 introduce the refrigerant in the refrigerant pipe 53, respectively, and exchange heat between the introduced refrigerant and ambient air. As can be seen from FIG. 12, an expansion valve 56 is interposed in the middle of the refrigerant pipe 53 that connects the indoor heat exchanger 54 and the outdoor heat exchanger 55. The expansion valve 56 expands the refrigerant in the refrigerant pipe 53.

The four-way switching valve 57 is connected to the discharge port 521 of the compressor 52 via the refrigerant pipe 53. The four-way switching valve 57 is configured to be able to selectively switch between a heating connection state and a cooling connection state. When the four-way switching valve 57 is in the heating connection state, the discharge port 521 of the compressor 52 and the indoor heat exchanger 54 are communicated with each other via the four-way switching valve 57 and the suction port 522 of the compressor 52 and the outdoor heat exchanger 55 are connected. Are communicated via a four-way switching valve 57. On the other hand, when the four-way switching valve 57 is in the cooling connection state, the discharge port 521 of the compressor 52 and the outdoor heat exchanger 55 are communicated with each other via the four-way switching valve 57, and the suction port 522 of the compressor 52 and the indoor heat are connected. The exchanger 54 is in communication with the four-way switching valve 57. During the heating operation, the four-way switching valve 57 is in a heating connection state, and during the cooling operation, the four-way switching valve 57 is in a cooling connection state. An exhaust heat recovery heat exchanger 65 and an accumulator 58 are interposed in the middle of the refrigerant pipe 53 that connects the four-way switching valve 57 and the suction port 522 of the compressor 52.

  A cooling water circuit 60 is connected to the gas engine 51. The cooling water circuit 60 is configured by a cooling water pipe filled with cooling water. In the middle of the cooling water circuit 60, a pump 64 and an exhaust heat recovery heat exchanger 65 are interposed. By operating the pump 64 while the gas engine 51 is being driven, the cooling water in the cooling water circuit 60 cools the gas engine 11. The exhaust heat recovery heat exchanger 65 exchanges heat between the cooling water in the cooling water circuit 60 heated by receiving heat from the gas engine 11 and the refrigerant flowing through the refrigerant pipe between the four-way switching valve 57 and the accumulator 58. .

  The heating operation and cooling operation of GHP2 will be briefly described. First, the heating operation will be described. When the compressor 52 is driven by the gas engine 51, low-pressure gas refrigerant is sucked into the compressor 52 from the suction port 522 and the sucked low-pressure gas refrigerant is compressed. Then, the compressed high-pressure gas refrigerant is discharged from the discharge port 521. The high-pressure gas refrigerant discharged from the discharge port 521 is introduced into the indoor heat exchanger 54 via the four-way switching valve 57. The high-pressure gas refrigerant introduced into the indoor heat exchanger 54 emits heat to the indoor air and condenses while circulating in the indoor heat exchanger 54. At this time, the indoor air is warmed by the heat discharged from the high-pressure gas refrigerant, and the room is heated.

  The refrigerant condensed by exhausting heat to the indoor air is partially liquefied and discharged from the indoor heat exchanger 54. Then, the pressure is reduced by expansion by the expansion valve 56 and then introduced into the outdoor heat exchanger 55. While the refrigerant introduced into the outdoor heat exchanger 55 flows through the outdoor heat exchanger 55, it takes away heat from the outside air and partially evaporates.

  The refrigerant that has partially taken away heat from the outside air is discharged from the outdoor heat exchanger 55, passes through the four-way switching valve 57, and further passes through the exhaust heat recovery heat exchanger 65. At this time, the refrigerant is heated by the cooling water of the gas engine 51. Thereafter, the refrigerant is supplied to the accumulator 58. In the accumulator 58, the refrigerant is separated into a liquid refrigerant and a low-pressure gas refrigerant. Then, only the low-pressure gas refrigerant returns to the compressor 52 from the suction port 522 of the compressor 52.

  Next, the cooling operation will be described. When the compressor 52 is driven by the gas engine 51, high-pressure gas refrigerant is discharged from the discharge port 521 of the compressor 52. The high-pressure gas refrigerant discharged from the discharge port 521 is introduced into the outdoor heat exchanger 55 via the four-way switching valve 57. The high-pressure gas refrigerant introduced into the outdoor heat exchanger 55 is condensed by discharging heat to the outside air while circulating in the outdoor heat exchanger 55.

  The refrigerant that is condensed by discharging heat to the outside air is partially liquefied and discharged from the outdoor heat exchanger 55. Then, the pressure is reduced by expansion by the expansion valve 56 and then introduced into the indoor heat exchanger 54. While the refrigerant introduced into the indoor heat exchanger 54 circulates in the indoor heat exchanger 54, it takes away the heat of the indoor air and partially evaporates. At this time, the refrigerant removes heat from the room air, thereby cooling the room air and cooling the room.

  The refrigerant that has partially taken away heat from the indoor air is discharged from the indoor heat exchanger 54, passes through the four-way switching valve 57, and further passes through the exhaust heat recovery heat exchanger 65. At this time, the refrigerant is heated by the cooling water of the gas engine 51. Thereafter, the refrigerant is supplied to the accumulator 58. In the accumulator 58, the refrigerant is separated into a liquid refrigerant and a low-pressure gas refrigerant. Then, only the low-pressure gas refrigerant returns to the compressor 52 from the suction port 522 of the compressor 52.

  The indoor remote controller 59 is configured so that the user can set the indoor set temperature and the like. While the gas engine 11 is being driven, the temperature set by the indoor remote controller 59 and information (indoor temperature information) S regarding the actual indoor temperature are input to the engine control device 30.

  A pressure sensor 62 is attached in the middle of the refrigerant pipe 53 that connects between the discharge port 521 of the compressor 52 and the four-way switching valve 57. The pressure sensor 62 detects the discharge pressure Ph of the compressor 52. Information regarding the detected discharge pressure Ph is input to the engine control device 30.

  The gas engine 51 is provided with a rotation speed sensor 63 that detects the engine rotation speed. Information regarding the engine speed R detected by the speed sensor 63 is input to the engine control device 30.

Further, a coolant temperature sensor 61 that detects the temperature of coolant discharged from the gas engine 51 is attached to the coolant circuit 60. Information regarding the coolant temperature Tw detected by the coolant temperature sensor 61 is input to the engine control device 30.

  While the gas engine 51 is being driven, the engine control device 30 inputs information from various sensors as described above. Note that detection information from sensors other than the above-described sensors may be input to the engine control device 30. And the engine control apparatus 30 controls the engine speed and driving | running state of the gas engine 51 based on the input information. As with the gas engine of the first embodiment, the operation state of the gas engine 51 of the present embodiment is configured to be switchable between a normal cycle operation and a mirror cycle operation.

  The engine control device 30 according to the present embodiment also includes a rotation speed control unit 31 and an operation state control unit 32 as in the engine control device 30 described in the first embodiment (see FIG. 5). The rotational speed control unit 31 controls the engine rotational speed R of the gas engine 51 by executing a rotational speed control routine while the gas engine 51 is being driven.

  FIG. 13 is a flowchart showing a rotation speed control routine executed by the rotation speed control unit 31 according to the present embodiment. When this routine is started, the rotational speed control unit 31 firstly receives information (cooling water temperature Tw, engine rotational speed R, discharge pressure Ph, indoor temperature information S, etc.) input to the engine control device 30 in S51 of FIG. ). Next, an air conditioning energy amount (required air conditioning energy amount) L required for the GHP 2 is calculated based on the read information (S52). The required air conditioning energy L can be calculated from, for example, the difference between the set temperature obtained from the room temperature information S and the actual room temperature. Next, the rotation speed control unit 31 calculates the drive output (required drive output) T of the gas engine 51 required for the GHP 2 to generate the required air conditioning energy L (S53). Subsequently, the rotation speed control unit 31 refers to the characteristic diagram of the drive output with respect to the rotation speed when the gas engine 51 is operated in the mirror cycle, and determines the engine rotation speed corresponding to the required drive output T as the required rotation speed Rr. (S54).

  FIG. 14 is a characteristic diagram of the drive output with respect to the rotation speed when the gas engine 51 is operated in a mirror cycle. As shown in FIG. 14, as the rotational speed increases, the drive output also increases. The rotational speed control unit 31 calculates the required rotational speed Rr corresponding to the necessary drive output T with reference to such a characteristic diagram.

  After calculating the required rotational speed Rr in S54, the rotational speed control unit 31 outputs the calculated required rotational speed Rr to the gas engine 51 (S55). Thus, the engine speed of the gas engine 51 is controlled so that the engine speed of the gas engine 51 matches the required speed Rr. Thereafter, the rotation speed control unit 31 ends this routine.

  The engine speed of the gas engine 51 changes according to the magnitude of the air conditioning energy amount L required for the GHP by the engine speed controller 31 executing the engine speed control routine as described above. Specifically, the engine speed of the gas engine 51 is controlled so that the engine speed decreases as the required air conditioning energy amount L decreases. Therefore, it is possible to obtain a power generation amount commensurate with the required air conditioning energy amount L, and to suppress wasteful power generation. For this reason, engine efficiency can be improved.

  Further, while the gas engine 51 is being driven, the operation state control unit 32 of the engine control device 30 executes an operation state control routine. FIG. 15 is a flowchart showing an operation state control routine executed by the operation state control unit 32 according to the present embodiment. When the operation state control routine is activated, the operation state control unit 32 first determines whether or not the operation state of the GHP is a specific operation state in S61 of FIG. Here, the specific operation state is an operation state in which it is determined that a large amount of air conditioning energy is necessary. For example, an operating state in which it is determined that an air conditioning energy amount larger than the air conditioning energy amount that can be obtained when the gas engine 51 is operated in a mirror cycle at the rotational speed controlled by the rotational speed control unit 31. However, the specific operation state may be set.

  As the specific operation state, for example, an initial startup state can be cited. Since the comfort can be increased by rapidly air-conditioning the GHP at the beginning of startup, a larger amount of air-conditioning energy than originally required is required. Moreover, as a specific operation state, a low temperature heating operation state is mentioned, for example. During heating operation (low temperature heating operation) when the outside air temperature is lower than a predetermined set temperature, heat cannot be sufficiently collected from the outside air. In this case, the air conditioning energy larger than the air conditioning energy obtained by collecting from outside air is required. Moreover, a defrost operation state is mentioned as a specific operation state. During the defrosting operation, more air conditioning energy is required to shorten the defrosting period as much as possible. Thus, the specific operation state is an operation state of the GHP 2 that is determined to require a large amount of air conditioning energy. Note that whether or not the operating state of the GHP 2 is the specific operating state may be determined based on information from various sensors input to the engine control device 30. Or you may be comprised so that the engine control apparatus 30 may acquire the driving | running state of GHP2 from the GHP control apparatus (not shown) provided in GHP2.

  If the operation state control unit 32 determines in S61 that the operation state of the GHP2 is the specific operation state (S61: Yes), the operation state control unit 32 outputs a normal operation signal to the gas engine 51 (S62). Thereby, the operation state of the gas engine 51 is set to the normal cycle operation. Thereafter, the operating state control unit 32 ends this routine.

  On the other hand, when it is determined in S61 that the operation state of GHP2 is not the specific operation state (S61: No), a mirror operation signal is output to the gas engine 11 (S63). As a result, the operation state of the gas engine 51 is changed to the mirror operation state. Thereafter, the operating state control unit 32 ends this routine.

  When the operation state control unit executes the operation state control routine described above, when the operation state of the GHP 2 is not the specific operation state, the operation state of the gas engine 51 is set to the mirror cycle operation. For this reason, GHP2 can be driven efficiently.

  When the operation state of the GHP 2 is a startup initial state that is one of the specific operation states, the operation state of the gas engine 51 is set to the normal cycle operation. For this reason, although the efficiency is lowered, the engine output is increased, so that the room temperature can be quickly reached the target temperature and the comfort can be improved.

  Further, when the operation state of the GHP 2 is a low temperature heating operation state that is one of the specific operation states, the operation state of the gas engine 51 is set to the normal cycle operation. For this reason, although the efficiency is reduced, the amount of heat exhausted from the gas engine 51 is increased, so that the amount of heat transferred to the refrigerant in the exhaust heat exchanger 65 is increased. In this way, the shortage of heat that cannot be sufficiently obtained from the outside air can be compensated.

  Moreover, also when the operation state of GHP2 is a defrost operation state which is one of the specific operation states, the operation state of the gas engine 51 is set to the normal cycle operation. For this reason, although the efficiency is reduced, the amount of heat exhausted from the gas engine 51 is increased, so that the amount of heat transferred to the refrigerant in the exhaust heat exchanger 65 is increased. For this reason, the temperature of the refrigerant | coolant sent to the outdoor heat exchanger 55 at the time of a defrost operation increases more, and it can defrost quickly.

  The embodiment of the present invention has been described above. The first embodiment is used in a gas engine cogeneration system 1 that generates electric energy and thermal energy, and its operation state can be switched between a normal cycle operation and a mirror cycle operation, and a drive output is used for electric energy. A control device (engine control device 30) of the gas engine 11 in which exhaust heat is used for heat energy is disclosed. The engine control device 30 includes a rotation speed control unit 31 and an operation state control unit 32. The rotational speed control unit 31 gasses the amount of electrical energy corresponding to the required electrical energy amount H to the gas engine cogeneration system 1 based on the output characteristics (FIG. 7) with respect to the rotational speed of the gas engine 11 during mirror cycle operation. The rotation speed of the gas engine 11 is controlled so that the engine cogeneration system 1 can be generated. The operating state control unit 32 has a predicted thermal energy amount H1 that is predicted to be generated by the gas engine cogeneration system 1 when the gas engine 11 is operated in a mirror cycle at the rotational speed controlled by the rotational speed control unit 31. When the required thermal energy amount H to the cogeneration system 1 is equal to or higher than the required thermal energy amount H, the operation state of the gas engine 11 is the mirror cycle operation, and when the predicted thermal energy amount H1 is less than the required thermal energy amount H, The operation state of the gas engine 11 is controlled so that the normal cycle operation is performed.

  According to the first embodiment, an efficient operation of the gas engine 11 by performing the mirror cycle operation at the rotation speed controlled according to the required electric energy amount H, and sufficient thermal energy by performing the normal cycle operation. Can be made compatible with the supply of In addition, when the required heat energy is low, the operation state of the gas engine 11 is basically a mirror cycle operation with a low output, so that the low load operation can be performed only by controlling the rotation speed of the gas engine 11. Therefore, partial load operation at low load can be avoided.

  Moreover, the said 3rd Embodiment is used for GHP2, the operation state can be switched to a normal cycle operation and a mirror cycle operation, and the control apparatus of the gas engine 51 by which drive output and waste heat are utilized for air-conditioning energy (Engine control device 30) is disclosed. The engine control device 30 also includes a rotation speed control unit 31 and an operation state control unit 32. Based on the output characteristics (FIG. 14) with respect to the rotational speed of the gas engine during the mirror cycle operation, the rotational speed control unit 31 is configured so that the GHP2 generates air conditioning energy corresponding to the required air conditioning energy amount L for GHP. The number of revolutions of the engine 51 is controlled. The operation state control unit 32 is configured such that the operation state of the gas engine 51 is a normal cycle operation when the operation state of the GHP2 is the specific operation state, and the operation state of the gas engine 51 is a mirror when the operation state of the GHP2 is not the specific operation state. The operation state of the gas engine 51 is controlled so that the cycle operation is performed.

  According to the third embodiment, the efficient operation of the gas engine 51 by performing the mirror cycle operation at the rotation speed controlled according to the required air conditioning energy amount L and the normal cycle operation when in the specific operation state. It is possible to achieve both sufficient supply of air-conditioning energy. Further, when the operating state of the gas engine 51 is not in the specific operating state, the operating state of the gas engine 51 is, as a rule, a mirror cycle operation with a low output. Therefore, partial load operation at low load can be avoided.

  The gas engine 11 shown in the first embodiment includes a cam unit 82 that is attached to a camshaft 81 and has an intake normal cam 84 and an intake mirror cam 83 for operating the intake valve 90, an intake valve 90, and a cam. It operates so that the connection state with the unit 82 can be switched between a normal connection state in which the intake valve 90 operates according to the cam profile of the normal cam 84 and a mirror connection state in which the intake valve 90 operates according to the cam profile of the mirror cam 83. Pins 877. Further, the normal cam 84 is configured so that the operation state of the gas engine 11 becomes a normal cycle operation when the intake valve 90 is operated according to the cam profile, and the mirror cam 83 is operated with the intake valve 90 operated according to the cam profile. In this case, the operation state of the gas engine 11 is configured to be a mirror cycle operation. According to this, the driving | running state control part 32 controls the action | operation of the pump 877, and can switch the driving | running state of the gas engine 11 easily.

  In the gas engine 11 shown in the second embodiment, the cam unit 82 includes a plurality of mirror cams (831, 832, 833) having different cam profiles. The operation state control unit 32 then selects one of the plurality of mirror cams (831, 832, 833) based on the required heat energy amount H when the operation state of the gas engine 11 is the mirror cycle operation. And the pin 877 is controlled so that the intake valve 90 operates according to the cam profile of one selected mirror cam. Specifically, a cam having a larger expansion ratio with respect to the compression ratio is selected as the required heat energy amount H is smaller. According to this, the engine efficiency can be further improved by selecting a mirror cam that is more efficient as the required heat energy amount H is smaller.

  The present invention should not be limited to the above embodiment. For example, in the third embodiment, the control device for the gas engine used in the GHP that performs only air conditioning has been described. However, in addition to air conditioning, the supply of electric energy by power generation and the supply of thermal energy by recovery of engine exhaust heat are also possible. The present invention can also be applied to a control device for a gas engine used for GHP that can be performed. Thus, the present invention can be modified without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... Gas engine cogeneration system, 10 ... Cogeneration unit, 11 ... Gas engine, 11a ... Speed sensor, 12 ... Generator, 14 ... Engine cooling water circuit, 16 ... Engine waste heat exchanger, 20 ... Waste heat recovery Unit: 23 ... Exhaust heat recovery circuit, 30 ... Engine control device, 31 ... Rotational speed control unit, 32 ... Operating state control unit, 42 ... Power measuring device, 51 ... Gas engine, 52 ... Compressor, 53 ... Refrigerant piping, 54 ... Indoor heat exchanger, 55 ... Outdoor heat exchanger, 56 ... Expansion valve, 57 ... Four-way switching valve, 58 ... Accumulator, 59 ... Indoor remote control, 60 ... Cooling water circuit, 61 ... Cooling water temperature sensor, 62 ... Pressure sensor , 63 ... Rotational speed sensor, 81 ... Cam shaft, 82 ... Cam unit, 83 ... Mirror cam for intake, 831 ... First mirror cam for intake, 83 2nd mirror cam for intake, 833 ... 3rd mirror cam for intake, 84 ... Normal cam for intake, 85 ... Cam for exhaust, 86 ... Rocker shaft, 871 ... First roller rocker arm, 872 ... Second roller rocker arm, 873 ... third roller rocker arm, 874 ... fourth roller rocker arm, 875 ... fifth roller rocker arm, 876 ... passage, 877 ... pin (switching mechanism), 88 ... push rod for intake, 89 ... push rod for exhaust, 90 ... Intake valve, 91 ... Exhaust valve, E ... Required electrical energy amount, Eth ... Reference electrical energy amount, H ... Required thermal energy amount, Hth ... Reference thermal energy amount, L ... Air conditioning load, R ... Engine speed, Rr ... Required rotational speed, Rth ... Reference rotational speed

Claims (4)

Used in gas engine cogeneration systems that generate electrical and thermal energy, normal cycle operation to achieve a thermodynamic cycle where the expansion ratio and compression ratio are equal, and heat that causes the expansion ratio to be greater than the compression ratio A control device for a gas engine that can switch an operation state to a mirror cycle operation that realizes a mechanical cycle, uses a drive output for electric energy, and uses exhaust heat for heat energy,
Based on the output characteristics with respect to the rotational speed of the gas engine during mirror cycle operation, the gas engine cogeneration system can generate an electric energy amount corresponding to the required electric energy amount to the gas engine cogeneration system. A rotational speed control unit for controlling the rotational speed of the gas engine;
The predicted amount of heat energy predicted to be generated by the gas engine cogeneration system when the gas engine is operated in a mirror cycle at the rotation speed controlled by the rotation speed control unit is the required heat to the gas engine cogeneration system. When the energy amount is equal to or greater than the amount of energy, the operation state of the gas engine is a mirror cycle operation, and when the predicted heat energy amount is less than the required heat energy amount, the operation state of the gas engine is a normal cycle operation. An operating state control unit for controlling the operating state of the gas engine;
A control device for a gas engine. Used in gas heat pumps, the operation state can be switched between normal cycle operation that realizes a thermodynamic cycle with the same expansion ratio and compression ratio and mirror cycle operation that realizes a thermodynamic cycle with an expansion ratio larger than the compression ratio. There is a control device for a gas engine in which drive output and exhaust heat are used for air conditioning energy,
Based on the output characteristics with respect to the rotational speed of the gas engine during mirror cycle operation, the rotational speed of the gas engine is controlled so that the gas heat pump generates air conditioning energy corresponding to the amount of air conditioning energy required for the gas heat pump. A rotational speed control unit,
When the operation state of the gas heat pump is a specific operation state that is predetermined as an operation state that requires a large amount of air conditioning energy, the operation state of the gas engine is a normal cycle operation, and the operation state of the gas heat pump is the specific operation state. An operating state control unit that controls the operating state of the gas engine so that the operating state of the gas engine becomes a mirror cycle operation when not in a state;
A control device for a gas engine. The control device for a gas engine according to claim 2,
The specific operation state includes an initial operation state that is within a predetermined time after the operation of the gas heat pump is started, and low-temperature heating in which the gas heat pump performs a heating operation when an outside air temperature is equal to or lower than a predetermined temperature. A control device for a gas engine, which is one of an operation state and a defrost operation state in which the gas heat pump performs a defrost operation. In the control device of the gas engine according to any one of claims 1 to 3,
The gas engine is attached to a camshaft and includes a cam unit having a normal cam for intake and an intake mirror cam for operating an intake valve, and a connection state between the intake valve and the cam unit. A switching mechanism that operates so as to be able to switch between a normal connection state in which the intake valve operates according to and a mirror connection state in which the intake valve operates according to a cam profile of the mirror cam,
The normal cam is configured such that when the intake valve is operated according to the cam profile, the operating state of the gas engine is the normal cycle operation,
The mirror cam is configured such that the operating state of the gas engine is the mirror cycle operation when the intake valve is operated according to the cam profile,
The operation state control unit controls the operation state of the gas engine by controlling the operation of the switching mechanism.

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