JP4705845B2 - Engine driven heat pump - Google Patents

Description

  The present invention relates to an engine-driven heat pump, and more particularly to a startup technology for an engine-driven heat pump including a compressor driven by a engine via a clutch.

  Conventionally, a heat pump device that circulates a refrigerant using a compressor driven by an engine is well known as an engine-driven heat pump. In this engine-driven heat pump, the transmission of power to the compressor is interrupted, that is, the operation of the compressor is switched between on and off, and the ON / OFF of a clutch such as an electromagnetic clutch interposed between the compressor and the engine drive shaft. -Some are performed by ОFF.

In this engine-driven heat pump, if the clutch is turned ON after the engine is started, the engine may become less than a predetermined number of rotations due to the torque fluctuation at the start of the compressor, and engine stall may occur. In Patent Document 1, when starting with the engine and the compressor connected, until the engine is warmed up, the start-up torque is suppressed by the capacity control on the compressor side or the refrigerant high / low pressure bypass, or the fuel at the start-up An activation control is disclosed in which the engine stall is prevented and the engine is quickly activated by maximizing the injection amount and the torque.
JP-A-6-221713

  However, in this prior art, when a cell motor is used for engine start-up, an output for always driving both the engine and the compressor is required, and a large amount of current flows through the cell motor at each start-up, so that the cell motor deteriorates early. There is a fear.

  In an engine-driven heat pump, after engine startup, in order to prevent engine stalls due to torque fluctuations at the start of the compressor, it is assumed that the engine and compressor are in a connected state (clutch ON). In addition, it is necessary to prevent a large amount of current from flowing through the cell motor to prevent early deterioration of the cell motor. Therefore, the problem to be solved is to achieve both reduction of engine stall and prevention of early deterioration of the cell motor at the start of the engine-driven heat pump.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

In claim 1, in the engine-driven heat pump having a compressor driven by the engine via the clutch, it is determined whether or not the previous time was the clutch ON activation. It is determined whether or not the predetermined time has elapsed, and if the previous time was a clutch OFF start, or if the previous operation time was a predetermined time or longer, the clutch was turned OFF and the clutch was turned ON after starting the engine. When the engine has stalled, a starting means is provided that restarts the engine once with a clutch ON after forcibly stopping the engine.

  According to a second aspect of the present invention, in the engine-driven heat pump according to the first aspect, when the engine is restarted as the clutch ON, when the engine stops after continuing operation for a predetermined time or more, the clutch is turned off next time. As a starting means for starting the engine.

  The engine-driven heat pump according to claim 3, wherein a plurality of the compressors are provided, and when the load is large or small among the compressors, the compressor is started from a small load side of the compressor, and the compressor When the load is equal, start means for starting the compressor alternately is provided.

  According to a fourth aspect of the present invention, in the engine-driven heat pump according to the first aspect, a bypass path that connects a discharge side and a suction side of the compressor is provided, and an activation unit that communicates the bypass path when the engine is activated is provided.

  According to a fifth aspect of the present invention, in the engine-driven heat pump according to the first aspect, when the engine is started with the clutch turned ON, the engine is stalled, and then the engine is restarted with the clutch turned to OFF.・ Equipped with a starting means to generate a warning when a stall occurs.

  6. The engine-driven heat pump according to claim 1, further comprising start means for starting the engine with the clutch being set to ONF, the cell motor being set to ON, and the clutch being set to ON immediately after the cell motor is set to OFF. It was.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, since it is possible to prevent the cell motor from prematurely deteriorating because it can be based on the start-up with the clutch as OFF, and when the engine stalls, the engine- The recurrence of stall occurrence can be reduced.

  According to the second aspect of the present invention, when the engine starts and stops at a short time interval due to the thermo-OFF, etc., the engine stall can be reduced, and when the engine stops after a predetermined time of operation, the clutch is returned to the start-up. Thus, early deterioration of the cell motor can be prevented.

  In the third aspect, in addition to the effect of the first or second aspect, the compressor starting torque can be reduced. Moreover, when there are a plurality of compressors, the total operating time of each compressor can be made uniform.

  In the fourth aspect, in addition to the effect of the first or second aspect, the discharge side and the suction side of the compressor can be bypassed to reduce the compressor starting torque when starting the engine.

  In claim 5, in addition to the effect of claim 1 or 2, an abnormality can be detected early.

  According to the sixth aspect of the present invention, the power of the cell motor can only drive the engine load and prevent early deterioration of the cell motor. Further, since the compressor starts to be driven when the rotational acceleration is applied, the engine speed can be suppressed, and the prevention of engine stall can be reduced.

  Next, embodiments of the invention will be described. FIG. 1 is a refrigerant circuit diagram of an engine-driven heat pump according to the present invention, FIG. 2 is a graph showing a change in the engine speed of a start pattern from the clutch OFF, and FIG. 3 is a graph of the engine speed of the start pattern from the clutch ON. It is a graph which shows a change. FIG. 4 is a graph showing a change in engine speed in a start (hereinafter referred to as “cell motor OFF” start) pattern in which the clutch is ON immediately after the cell motor OFF, and FIG. 5 is a first embodiment of the engine start control according to the present invention. FIG. 6 is a flowchart showing the second embodiment. FIG. 7 is a refrigerant circuit diagram showing the refrigerant behavior of the first embodiment of engine-driven heat pump activation control, FIG. 8 is a refrigerant circuit diagram showing the refrigerant behavior of the second embodiment, and FIG. 9 is the refrigerant of the third embodiment. It is a refrigerant circuit diagram which shows a behavior.

  Next, embodiments of the invention will be described with reference to the drawings. A drive source configuration and a refrigerant circuit configuration of an engine-driven heat pump according to the present invention will be described with reference to FIG.

  The engine-driven heat pump 1 according to the present invention has two compressors 2a and 2b that are selectively driven simultaneously or only by an engine 4 as a drive source. Is used for air conditioning. Intermittent motive power from driving the engine 4 to the compressor 2, that is, switching between operation and stop of the compressor 2, is interposed between a driving pulley (not shown) of the compressor 2 and a driving shaft of the compressor 2. This is performed by turning on and off the clutch 3 to be performed. In this embodiment, the clutch 3 is an electromagnetic clutch having a known configuration. The engine 4 uses a gas engine that uses city gas or the like as a fuel, or a liquid fuel such as kerosene, and is provided with a cell motor (starter) 5 that cranks the engine 4. The waste heat of the engine 4 is cooled by circulating cooling water, and this cooling water is cooled by a radiator (not shown) and the waste heat recovery unit 24. The engine 4, the clutch 3 and the cell motor 5 are controlled by a controller 100 as a control means.

  The engine-driven heat pump 1 according to the present invention includes the compressor 2, a four-way valve 13 that is connected to the discharge side of the compressor 2 and switches the flow of refrigerant during cooling and heating, and four-way valves from the compressor 2 during cooling. An outdoor heat exchanger 14 to which refrigerant is supplied via the valve 13, an indoor heat exchanger 15 to which refrigerant is supplied from the compressor 2 via the four-way valve 13 during heating, the outdoor heat exchanger 14 and the indoor heat exchange It has the outdoor expansion valve 16 arrange | positioned between the containers 15, and uses the refrigerant | coolant cycle comprised by these.

  The compressor 2 has a discharge path 31 connected to the discharge side and a suction path 32 connected to the suction side. That is, one end of the four-way valve 13 is connected via a discharge path 31 on the discharge side of the compressor 2, and the compressor 2 sucks and compresses the gas refrigerant passing through the suction path 32, thereby increasing the temperature and pressure. The gas refrigerant is discharged into the discharge path 31. The discharge path 31 is provided with an oil separator (oil separator) 8 for separating the compressor oil (lubricating oil) contained in the high-temperature and high-pressure gas refrigerant and returning it to the suction side of the compressor 2. It has been. That is, the gas refrigerant discharged from the compressor 2 flows into the four-way valve 13 via the oil separator 8 and is guided in a predetermined direction by the four-way valve 13. Further, the suction side of the compressor 2 and another end of the four-way valve 13 are connected, and the gas refrigerant sucked into the compressor 2 is also guided by the four-way valve 13. Further, a bypass path 33 that short-circuits the discharge path 31 and the suction path is provided via the bypass expansion valve 25.

  Another end of the four-way valve 13 is connected to one end of the indoor heat exchanger 15, and a liquid refrigerant receiver 22 for storing liquid refrigerant is connected to the other end of the indoor heat exchanger 15. It is connected. The liquid refrigerant receiver 12 is connected to the suction path 30 via a path 35, and the refrigerant flowing out from the liquid refrigerant receiver outlet 22 c after being used for supercooling by the liquid refrigerant receiver 22 is connected to the path 35 in the engine. A waste heat recovery device 24 for evaporating with the heat of the cooling water (warm water) 4 is provided. Similarly, the outdoor heat exchanger 14 is connected to the other end of the four-way valve 13, and the outdoor expansion valve is connected to a path 34 connecting the outdoor heat exchanger 14 and the indoor heat exchanger 15. 16 is provided.

  Next, an engine starting method of the engine driven heat pump 1 according to the present invention will be described with reference to FIGS. As shown in FIG. 2, the horizontal axis indicates time T, the vertical axis in the graph of engine speed indicates the engine speed N, and the vertical axis indicating the operating status of the cell motor 5 and the clutch 3 is ON or ОFF operation is shown. Further, the engine is controlled to rotate at the set rotational speed No by the controller 100 at the rotational speed N. Hereinafter, the same applies to the graphs of FIGS. 3 and 4.

  FIG. 2 shows a change in the engine speed N in the engine starting method in which the clutch 3 is turned on after the engine 4 is started (hereinafter referred to as “clutch ONF activation”). In this clutch OFF activation, when the engine 4 is activated by the cell motor 5 (T = t0), the temperature in the combustion chamber rises, the fuel ignites and burns, and the rotation of the engine 4 rises (T = t1). 5 is OFF, and the engine 4 is controlled so as to approach the target rotational speed No. When the engine speed N is No and the clutch 3 is turned on (T = t2), resistance due to the clutch 3 being connected and resistance due to starting compression work in the compressor 2 (compressor The engine speed N temporarily decreases at (starting torque) (see A in FIG. 2). The decrease in the engine speed N after the clutch ON causes an engine stall (engine stall).

  FIG. 3 shows a change in the engine speed N in the engine starting method in which the clutch 3 is turned ON simultaneously with the starting of the engine 4 (hereinafter referred to as clutch ON starting). When the clutch ON is started, the engine 4 is started by the cell motor 5 (T = t0) while the clutch is ON, and when the rotation of the engine 4 starts up (T = t1), the cell motor 5 is set to ONF. Control is performed so as to approach the target rotational speed No. This engine starting method requires an output for driving the engine load and the compressor starting torque only by the power of the cell motor 5, and an excessive current flows through the cell motor 5 every time the engine is started. Get early.

  FIG. 4 shows a change in the engine speed N in the engine starting method in which the cell motor 5 is set to OFF and the clutch 3 is set to ON after starting the engine 4 (hereinafter referred to as starting the cell motor OFF). In this cell motor OFF activation, the engine 4 is activated by the cell motor 5 (T = t0), the temperature in the combustion chamber rises, the fuel ignites and burns, and the rotation of the engine 4 rises (T = t1). 5 is set to ONF, and at the same time, the clutch 3 is set to ON (T = t2), and the engine 4 is controlled so as to approach the target rotational speed No. In this engine starting method, since the power of the cell motor 5 only drives the engine load, early deterioration of the cell motor 5 can be prevented. Further, the engine rotation speed N is not temporarily lowered unlike the clutch ON activation, and the prevention of engine stall can be reduced.

  Here, a first embodiment of the engine start control of the engine driven heat pump 1 according to the present invention will be described along the flowchart shown in FIG. As shown in FIG. 5, when the previous start of the engine 4 is the clutch ON start, the controller 100 further sets the operation time of the previous engine 4 for a predetermined time (in this embodiment, 2 hours. It is determined whether or not the configuration can be changed arbitrarily (S101). If the previous operation time of the engine 4 is 2 hours or more, the clutch ON is started (S201), and if it is 2 hours or less, the clutch OFF is started (S102). In other words, when the engine-driven heat pump 1 repeatedly starts and stops the engine at short intervals due to the start and stop of the thermostat, etc., the clutch motor FF is activated to prevent early deterioration of the cell motor 5, and when the engine is normally activated, the clutch ON is activated. Reduces engine stalls. Next, the engine 4 is started by starting the clutch OFF (S102). Here, if an engine stall has occurred (S103), the restart is defined as clutch ON activation (S201). If engine stall does not occur, normal operation is assumed. Further, after the clutch ON is started (S201), if an engine stall occurs (S202), the restart is set to the clutch OFF (S301). If engine stall does not occur, normal operation is assumed. Here, after the clutch OFF is started (S301), if an engine stall occurs (S302), the start of the engine 4 is stopped with a warning display (S401).

  In this way, by making the optimum selection of the clutch ON activation and the clutch OFF activation in accordance with the previous activation method and the previous engine operating time, based on the clutch OFF activation, the generation of engine stall and the cell motor can be reduced. Both prevention of early deterioration can be realized. Furthermore, when an engine stall occurs when the clutch О is started, the engine 100 is restarted when the clutch OF is started. However, when the engine stall occurs again, the controller 100 does not cause the torque fluctuation of the compressor, It is determined that an abnormality has occurred in the engine 4. In this way, it is possible to detect an abnormality early by giving up the start of the engine 4 and notifying the outside of the warning. The warning means is not particularly limited to the display means in the present embodiment, but a warning light or the like is lit on the operation unit, a warning sound is emitted from a speaker or a buzzer, or the position where the operator can easily check A method is preferred.

  Further, a second embodiment of engine start control of the engine driven heat pump 1 according to the present invention will be described with reference to a flowchart shown in FIG. As shown in FIG. 6, when the previous start of the engine 4 is the clutch ON start, the controller 100 further determines whether or not the previous operation time of the engine 4 is 2 hours or more (S501). If the previous operation time of the engine 4 is 2 hours or more, the clutch ON is started (S601), and if it is 2 hours or less, the cell motor OFF is started (S502). That is, when the engine-driven heat pump 1 repeatedly starts and stops the engine at short intervals due to the start and stop of the thermostat, etc., the cell motor 5 is activated to prevent premature deterioration of the cell motor 5, and in the normal activation, the clutch ON is activated. Reduces engine stalls. Next, the engine 4 is started by starting the cell motor OFF (S502). Here, if an engine stall has occurred (S503), the restart is set to clutch ON activation (S601). If engine stall does not occur, normal operation is assumed. Further, after the clutch ON is restarted (S601), if an engine stall occurs (S602), the restart is set as the cell motor OFF (S701). If engine stall does not occur, normal operation is assumed. Further, after the start of the cell motor OFF (S701), if an engine stall occurs (S702), the restart is set to the clutch OFF start (S801). If engine stall does not occur, normal operation is assumed. Here, after the clutch OFF is started (S801), if an engine stall occurs (S802), the start of the engine 4 is stopped with a warning display (S901).

  In this way, the engine stall can be generated by appropriately selecting the start of the cell motor OFF and the start of the clutch ON, and further the start of the clutch OFF according to the previous start method and the previous engine operation time, based on the start of the cell motor OFF. Both reduction and prevention of early deterioration of the cell motor can be realized. Furthermore, when an engine stall occurs when the cell motor IFF is activated, the engine stall is reduced by restarting with all the activation methods. If an engine stall occurs even after implementing these, it is possible to detect an abnormality early by giving up the engine 4 and giving a warning.

  Next, start-up control (hereinafter referred to as GHP start-up control) of the engine-driven heat pump 1 using the engine start-up control described above will be described below. As shown by the thick solid line in FIG. 7, the refrigerant behavior of the cooling operation of the engine-driven heat pump 1 will be described using the refrigerant circuit configuration. In addition, about heating operation, since it is starting control similar to cooling operation, description is abbreviate | omitted in a present Example. In the cooling operation, the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 2 is sent to the outdoor heat exchanger 14 through the four-way valve 13 through the discharge path 31, and in this outdoor heat exchanger 14. It is condensed by dissipating heat to the outside air blown by the outdoor fan 17, and this heat of condensation is dissipated into the outdoor air. Here, the high-temperature and high-pressure supersaturated gas refrigerant changes from gas to liquid. The liquefied refrigerant flows from the check valve 7a through the liquid refrigerant receiver outlet 22a into the liquid refrigerant receiver 22, and further from the liquid refrigerant receiver outlet 22b through the check valve 7b to the indoor expansion valve 18. The pressure is rapidly reduced by the indoor expansion valve 18 to be easily evaporated and led to the indoor heat exchanger 15. The indoor heat exchanger 15 serves as an evaporator, and the refrigerant removes heat of evaporation from the indoor air and changes from a liquid to a gas, and cools the indoor air. The vaporized refrigerant passes through the suction path 32 via the four-way valve 13 and is sucked and compressed by the compressor 2 and then discharged again.

  Here, a first embodiment of GHP activation control will be described with reference to FIG. As shown in FIG. 7, in the engine-driven heat pump 1 of this embodiment, two compressors 2 a and 2 b are driven by one engine 4. Here, for example, when the indoor cooling load is small, capacity control is performed by the compressor 2 and operation is performed at a capacity corresponding to the demand cooling load. Actually, the compressor 2 on the driving side is connected, that is, only the clutch 3a is turned ON and connected to the engine 4. In the engine-driven heat pump 1 of this embodiment, the capacities of the two compressors 2a and 2b are the same. In such a case, the two compressors 2a and 2b are started from only one different each time the engine is started. Specifically, only one of the compressors 2a is activated first, and then the compressor 2b is activated (thick solid line in FIG. 7). At the next activation, only one compressor 2b is activated (thick broken line in FIG. 7), and then the compressor 2a is activated.

  In this way, in the engine-driven heat pump 1 provided with a plurality of compressors 2, it is possible to avoid starting the plurality of compressors 2 at the same time, and to start up the engine 4 by starting only from one compressor 2. The load is reduced. Further, by alternately starting each time the engine is started, the operation loads of the two compressors 2 and the clutch 3 are made uniform.

  A second embodiment of GHP activation control will be described with reference to FIG. As shown in FIG. 8, in the engine-driven heat pump 1 of the present embodiment, the capacity of one compressor 2b out of the two compressors 2a and 2b is configured to be larger than the capacity of the other compressor 2a. . In such a case, the small compressor 2a is first activated. The thick solid line in FIG. 8 shows the refrigerant behavior of the engine-driven heat pump 1 at the time of startup.

  As described above, in the engine-driven heat pump 1 provided with a plurality of compressors 2 having large and small capacities, the engine starting torque is reduced by starting the compressor 2 having the minimum capacity first.

  Furthermore, a third embodiment of GHP activation control will be described with reference to FIG. As shown in FIG. 9, the controller 100 fully opens the bypass expansion valve 25 at the time of activation. By guiding the refrigerant to the bypass path 33 in this way, the pressure difference between the suction path 32 and the discharge path 31 is reduced, and the starting torque of the compressor 2 at the time of starting can be reduced.

  In the engine start control and the GHP start control described in the present embodiment, the effects of reducing the occurrence of engine stall and preventing early deterioration of the cell motor can be further exhibited by combining them. For example, when a plurality of compressors are provided, the bypass expansion valve 25 is fully opened at the time of start-up, and when there are a plurality of compressors having different capacities, a compressor with a small capacity is started. The compressor that is started alternately or first is made different at each stop. In addition, the refrigerant circuit structure of a present Example is an example of the refrigerant circuit structure which the engine drive type heat pump 1 which concerns on this invention has, and is not limited to this structure.

The refrigerant circuit figure of the engine drive type heat pump concerning the present invention. The graph figure which shows the change of the engine speed of the starting pattern from clutch OFF. The graph which shows the change of the engine speed of the starting pattern from clutch ON. The graph which shows the engine speed change of the starting (henceforth abbreviated as the cell motor OFF starting) which makes the clutch ON just after the cell motor OFF. The flowchart figure which shows the 1st Example of the engine starting control which concerns on this invention. The flowchart figure which similarly shows a 2nd Example. The refrigerant circuit figure which shows the refrigerant | coolant behavior of the 1st Example of engine drive type heat pump starting control. The refrigerant circuit figure which similarly shows the refrigerant | coolant behavior of a 2nd Example. The refrigerant circuit figure which similarly shows the refrigerant | coolant behavior of a 3rd Example.

1 Engine-driven heat pump 2 Compressor 3 Clutch 4 Engine

Claims (6)

In an engine-driven heat pump having a compressor driven by a clutch via an engine, it is determined whether or not the previous time was a clutch ON start. In the case of a clutch ON start, whether or not the previous operation time was a predetermined time or more When the previous time was the clutch OFF start, or when the previous operation time was a predetermined time or more, the clutch OFF start, the engine was started , and the clutch was turned ON , An engine-driven heat pump characterized by comprising an activation means for restarting the engine with a clutch ON after the engine has been forcibly stopped once the engine has stalled.   2. The engine-driven heat pump according to claim 1, wherein when the engine is restarted as the clutch ON and the engine stops after continuing operation for a predetermined time or more, the engine is started next time with the clutch as OFF. An engine-driven heat pump characterized by comprising an activation means.   2. The engine-driven heat pump according to claim 1, wherein a plurality of the compressors are provided, and when the load is large or small among the compressors, the compressor is started from a small load side of the compressor, and the load of the compressor is equalized. In such a case, an engine-driven heat pump characterized in that it includes start means for alternately starting the compressor.   2. The engine drive heat pump according to claim 1, further comprising a bypass path that connects a discharge side and a suction side of the compressor, and an activation unit that communicates the bypass path when the engine is activated. Type heat pump.   2. The engine-driven heat pump according to claim 1, wherein when the engine is started with the clutch set to ON, the engine is stalled, then the engine is restarted with the clutch set to OFF, and the engine is stalled again. Is an engine-driven heat pump, characterized in that it includes a starting means for generating a warning.   2. The engine-driven heat pump according to claim 1, further comprising starting means for setting the clutch to ON immediately after switching the cell motor to OFF after starting the engine with the clutch being set to OFF and the cell motor being ON. Engine-driven heat pump.

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