JP4557828B2 - Engine-driven air conditioner and control method thereof - Google Patents

Description

  The present invention relates to an engine-driven air conditioner that variably controls the rotational speed of an engine and circulates refrigerant discharged from a compressor driven by the engine to perform an air-conditioning operation and a control method therefor. It relates to load control.

2. Description of the Related Art Conventionally, a so-called engine-driven air conditioner that compresses and circulates refrigerant by driving a compressor of an outdoor unit by an engine using gas or the like as a fuel is known.
Some engine-driven air conditioners of this type variably control the engine speed according to the air conditioning load, and measure the outlet pressure of the compressor, the suction pressure, and the temperature of the refrigerant inlet / outlet of the heat exchanger. There is one that obtains a shaft output of a compressor from a measurement result and determines whether or not the engine is in an overload state based on the shaft output (for example, Patent Document 1). When it is determined that the engine is in an overload state, the engine load is reduced by, for example, restricting the expansion valve to avoid a decrease in engine life.
JP-A-6-137701

  By the way, when estimating the engine load from the shaft output of the compressor as described above, it is necessary to consider the volumetric efficiency and power efficiency of the compressor. However, the volumetric efficiency and power efficiency of the compressor are not constant, and there are problems that cannot be ignored due to the rotational speed of the compressor and the refrigerant pressure, making it difficult to accurately estimate the engine load.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an engine-driven air conditioner that can accurately determine whether an engine is in an overload state and appropriately avoid the engine overload state, and a control method therefor. There is.

In order to solve the above-described problems, the present invention variably controls the number of revolutions of an engine in accordance with an air-conditioning load, and refrigerant discharged from a compressor driven by the engine is converted into an outdoor heat exchanger, an indoor heat exchanger, In the engine-driven air conditioner that circulates between the air-conditioning operation , the fuel adjustment valve opening and the throttle opening are adjusted so that the engine rotates at a predetermined rotation speed while torque is applied to the engine. In this case, the engine torque value, ignition required voltage and excess air ratio are measured, and the measurement value when this measurement is performed a plurality of times by changing the torque applied to the engine and the engine speed, rotational speed of the engine, intake and storage means for storing fuel adjusting valve opening degree, and the throttle opening degree, the rotational speed of the engine, fuel adjusting valve opening degree, the throttle opening And the torque value of the engine by referring to the information stored in the storage unit based on the acquired information, to identify the ignition demand voltage and an excess air ratio, based on a comparison of the preset value with a specific value Te, the engine comprises judging means for judging whether or not the overload state, when the engine is determined to be in an overload condition, and control means for engine load reduction control to reduce the load of the engine It is characterized by that. In this invention, the engine speed, the fuel adjustment valve opening, and / or the throttle opening are all acquired, and the engine controlled according to the air conditioning load is overloaded based on the acquired information. Since it is determined whether or not there is, the engine load can be determined from the current control state of the engine, compared to the conventional one that determines whether or not the engine is overloaded indirectly from the compressor shaft output, It is possible to accurately determine whether or not the engine is in an overload state.

  In the above invention, a calculation formula for calculating at least one of the engine torque value, the ignition required voltage, and the excess air ratio from all or any of the engine speed, the fuel adjustment valve opening, and the throttle opening. Storage means for storing, and the determination means specifies at least one of the engine torque value, the ignition request voltage, and the excess air ratio from the acquired information using a calculation formula stored in the storage means Then, based on a comparison between the specified value and a preset setting value, it may be determined whether or not the engine is in an overload state.

  In the above invention, when the control means determines that the engine is in an overload state, an expansion valve corresponding to a heat exchanger functioning as an evaporator of the outdoor heat exchanger and the indoor heat exchanger is selected. Of the opening degree adjustment, the outdoor heat exchanger and the indoor heat exchanger, the rotation speed adjustment of the cooling fan for heat exchange functioning as a condenser, the adjustment of the engine speed, or the refrigerant high pressure part and the refrigerant low pressure part It is preferable to perform at least one of adjustment of the opening degree of the bypass valve of the bypass pipe provided therebetween. In this case, the control means has a lower limit value when adjusting the opening degree of the expansion valve corresponding to the heat exchanger functioning as the evaporator, and an upper limit value when adjusting the rotational speed of the cooling fan for heat exchange functioning as the condenser. The lower limit value at the time of adjusting the engine speed or the upper limit value at the time of adjusting the opening degree of the bypass valve may be changed according to the air conditioning load.

  In addition, a plurality of outdoor units having the compressor driven by the engine and the outdoor heat exchanger are provided, and even if the control by the determination unit and the control unit is performed in the outdoor unit in operation, the engine When the load state is continued, another stopped outdoor unit may be operated to reduce the engine load. In addition, in the outdoor unit in operation with a small capacity, comprising a plurality of outdoor units having different capacities having the compressor driven by the engine and the outdoor heat exchanger, control by the determination means and the control means Even if it is executed, when the engine overload state continues, it may be switched to the operation of the outdoor unit having a large capacity. A total control device for controlling a control device provided in each of the plurality of outdoor units, and even if the total control device is controlled by the determination means and the control means, the engine overload state is You may make it perform the said control in the case of continuing.

The present invention also variably controls the engine speed according to the air conditioning load, and circulates the refrigerant discharged from the compressor driven by the engine between the outdoor heat exchanger and the indoor heat exchanger. In the control method of the engine-driven air conditioner that performs air conditioning operation , the fuel adjustment valve opening and the throttle opening are adjusted so that the engine rotates at a predetermined rotation speed while torque is applied to the engine. The engine torque value, ignition required voltage, and excess air ratio are measured, and the measured value when this measurement is performed a plurality of times by changing the torque applied to the engine and the engine speed, and the engine at each measurement time. speed, fuel adjusting valve opening degree, and in a state in which the throttle opening is stored in advance in the storage means, the rotational speed of the engine, fuel adjusting valve opening degree, the throttle opening degree Acquired, the torque value of the engine by referring to the information stored in the storage unit based on the acquired information, to identify the ignition demand voltage and an excess air ratio, on a comparison of the preset value with a specific value On the basis of this, it is determined whether or not the engine controlled in accordance with the air conditioning load is in an overload state, and when it is determined that the engine is in an overload state, engine load reduction control is performed to reduce the load on the engine. It is characterized by performing. According to the present invention, the engine controlled according to the air conditioning load is overloaded based on the acquired information by acquiring all or any of the engine speed, the fuel adjustment valve opening, and the throttle opening. It is possible to determine the engine load from the current control state of the engine and to compare whether the engine is overloaded indirectly from the compressor shaft output. Thus, it can be accurately determined whether or not the engine is in an overload state.

  The present invention acquires the engine speed, the fuel adjustment valve opening, and / or the throttle opening, and based on the acquired information, the engine controlled according to the air conditioning load is overloaded. If it is determined whether or not the engine is in an overload state, engine load reduction control for reducing the engine load is performed, so that the engine load can be determined from the current control state of the engine. For this reason, it is possible to accurately determine whether or not the engine is overloaded, compared to the conventional one that indirectly determines whether or not the engine is overloaded from the shaft output of the compressor. An overload condition can be avoided appropriately.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of an engine-driven air conditioner 100 according to the present embodiment. The engine-driven air conditioner 100 includes a single outdoor unit 1 and a plurality of (for example, two) indoor units 2a and 2b, a refrigerant pipe (inter-unit pipe) 3 including a gas pipe 3a and a liquid pipe 3b. Connected and configured. The engine-driven air conditioner 100 includes a control device 4 that performs operation control of the air conditioner 100 and an operation unit 5 that performs operations such as an operation instruction of the control device 4.

  The operation unit 5 is a so-called remote control device that operates / stops the indoor units 2a, 2b, or a remote operation device that can check various settings and operation states of the indoor units 2a, 2b and the outdoor unit 1. It is. In the present embodiment, the engine-driven air conditioner 100 is configured to circulate an alternative refrigerant R410a having a high refrigerant capacity per unit volume and low pressure loss.

  The outdoor unit 1 is installed outdoors. The outdoor unit 1 is connected to an engine 10 that generates a driving force by burning fuel gas or the like, and a driving force transmitting means (not shown). A compressor 11 that compresses and discharges the refrigerant R410a, a four-way valve 12 that reverses the circulation direction of the refrigerant, an outdoor heat exchanger 13 that performs heat exchange between the refrigerant and the outside air, and an outdoor expansion valve 14 that depressurizes the refrigerant. An accumulator 15 that performs gas-liquid separation of the refrigerant sucked into the compressor 11 is connected and accommodated by a refrigerant pipe. An outdoor fan 16 that blows air to the outdoor heat exchanger 13 is disposed adjacent to the outdoor heat exchanger 13.

  In the outdoor unit 1, a bypass pipe 17 is connected between a refrigerant high-pressure part (discharge side of the compressor 11) and a refrigerant low-pressure part (in the illustrated example, before the accumulator 15). (Motorized valve) 18 is provided. By adjusting the opening degree of the bypass valve 18, a part of the refrigerant discharged from the compressor 11 through the bypass pipe 17 is guided to the suction side of the compressor 11, and the outdoor unit 1 and the indoor units 2 a and 2 b. Is adjusted.

  Further, the outdoor unit 1 is provided with a liquid pipe 40 for appropriately supplying the liquid refrigerant flowing through the pipe (liquid pipe) 19 on the outdoor unit 1 side before the accumulator 15 provided on the suction side of the compressor 11. The liquid pipe 40 is provided with a liquid valve (motor valve) 41. The liquid valve 41 is normally closed, and is opened when the refrigerant discharged from the compressor 11 exceeds a predetermined temperature (for example, 115 ° C. depending on the type of refrigerant), and the temperature is low from the pipe 19 on the outdoor unit 1 side. Liquid refrigerant is supplied to the front side of the accumulator 15. Thereby, the temperature of the gas refrigerant sucked into the compressor 11 is lowered, and overheating of the refrigerant discharged from the compressor 11 is prevented.

  The indoor units 2a and 2b include indoor heat exchangers 20a and 20b for exchanging heat between indoor air in which the indoor units 2a and 2b are installed and the refrigerant, and refrigerant flowing into the indoor units 2a and 2b. Indoor expansion valves 21a and 21b for controlling the amount of refrigerant are respectively connected and accommodated by refrigerant piping. Indoor fans 22a and 22b for sending air to the indoor heat exchangers 20a and 20b are arranged adjacent to the indoor heat exchangers 20a and 20b, respectively.

  A fuel / air mixture is supplied from the engine fuel supply device 31 to the combustion chamber of the engine 10 that drives the compressor 11. In the engine fuel supply device 31, a fuel cutoff valve 33, a zero governor 34, a fuel adjustment valve 35, and a throttle valve 36 are sequentially disposed in a fuel supply pipe 32, and the throttle valve 36 is connected to the combustion chamber of the engine 10. Has been. The fuel cut-off valve 33 constitutes a closed type fuel cut-off valve mechanism, and the fuel cut-off valve 33 is fully closed or fully opened, and the cut-off and communication without leakage of the fuel gas are performed alternatively.

  FIG. 2 is a block diagram illustrating a configuration of the control device 4. The control device 4 includes a setting unit 47 for setting operation instructions for the engine 10 and the compressor 11, various settings of the engine-driven air conditioner 100, a control program, control data, and a database 50 (FIG. 3). And the like, a CPU 43 that controls the entire engine-driven air conditioner 100 based on a control program in the EEPROM 42, a RAM 44 that temporarily stores various data, and an operation The transmission / reception part 45 which communicates with the part 5 and the interface (I / F) 46 for transmitting / receiving a signal with each part of the engine drive type air conditioning apparatus 100 are provided.

The control device 4 further includes a rotational speed detector (not shown) for detecting the rotational speed of the engine 10 and a temperature sensor (an indoor temperature sensor (not shown) for measuring the indoor temperature) via the I / F 46. And a temperature sensor (not shown) for measuring the refrigerant inlet / outlet temperature of the heat exchangers 13, 20a, 20b, and a temperature sensor 23a, 23b for measuring the temperature of air blown by the indoor fans 22a, 22b of the indoor units 2a, 2b. The engine speed and the temperature at each location can be acquired.
When the operation unit 5 is operated, the control device 4 includes the engine 10, the four-way valve 12, the outdoor expansion valve 14, the outdoor fan 16 in the outdoor unit 1, and the indoor expansion valves 21a, 21b in the indoor units 2a and 2b. The indoor fans 22a and 22b are controlled.

  Specifically, the control device 4 sets the air conditioning device 100 to the cooling operation or the heating operation by switching the four-way valve 12. That is, when the four-way valve 12 is switched to the cooling side, the refrigerant flows as indicated by the broken line arrows, the outdoor heat exchanger 13 functions as a condenser, and the indoor heat exchangers 20a and 20b function as an evaporator, thereby entering a cooling operation state. Each indoor heat exchanger 20a, 20b cools the room. When the control device 4 switches the four-way valve 12 to the heating side, the refrigerant flows as indicated by solid arrows, the indoor heat exchangers 20a and 20b function as a condenser, and the outdoor heat exchanger 13 functions as an evaporator. It will be in an operation state and each indoor heat exchanger 20a, 20b will heat a room.

  Further, the control device 4 determines the opening degree of the fuel adjustment valve 35 and the throttle valve 36 (fuel adjustment valve) based on the difference between the set temperature set by the operation unit 5 and the room temperature acquired by the room temperature sensor. The opening number and the throttle opening degree) are controlled to variably control the rotational speed of the engine 10, and the outdoor expansion valve 14 and the indoor expansion valve 21a are controlled based on the refrigerant inlet / outlet temperature difference of the heat exchangers 13, 20a, 20b. , 21b is controlled.

  During the air conditioning operation, the control device 4 determines whether or not the engine 10 to be controlled according to the air conditioning load is in an overload state. If the engine 10 is in the overload state, a process for reducing the engine load (engine load reduction). Process). In this embodiment, information (control information) indicating the current control state of the engine 10 such as the engine speed, fuel adjustment valve opening, and throttle opening of the engine 10 is acquired, and the database 50 is referred to based on this information. The engine 10 is determined to be overloaded. FIG. 3 is a diagram illustrating an example of the database 50.

  The database 50 is associated with engine speed, fuel adjustment valve opening, throttle opening, torque value of the engine 10, engine thermal efficiency, IG (ignition) required voltage, fuel gas flow rate, and λ (excess air ratio). is described. Among these, the engine speed, the fuel adjustment valve opening, and the throttle opening are information that can be measured during the control of the engine 10, and the torque value, the IG required voltage, and λ are whether the engine 10 is in an overload state. This is information for determining whether or not. In other words, if the torque value is excessive, the engine durability will be reduced, if the required IG voltage is high, the coil life will be reduced, and if λ is small, knocking may occur and the engine may be damaged. This is information (load specifying information) for specifying. The engine thermal efficiency is information used to determine whether or not the engine is operating at a rotational speed with good engine thermal efficiency during energy saving operation. The fuel gas flow rate is information that is preferably used in gas demand control and energy saving operation.

  For example, the database 50 applies a torque of 1, 3, 5, 7, 9, 11, 13 (kg · m) as a load to the engine 10 so that the engine 10 rotates at 1000 (rpm) for each torque. By adjusting the fuel adjustment valve opening and throttle opening, and measuring the fuel adjustment valve opening, throttle opening, fuel gas flow rate, torque value, engine thermal efficiency, IG required voltage, fuel gas flow rate and λ in that state Ask. Similarly, for engine speeds 1200 (rpm), 1400 (rpm)... 2000 (rpm), the fuel adjustment valve opening, throttle opening, fuel gas flow rate, engine thermal efficiency, IG required voltage, fuel at each torque The gas flow rate and λ are obtained by measurement or the like, and these measurement data are created by mapping and stored in the EEPROM 42 of the control device 4. Not only the actual measurement but also the values when the operating state of the engine 10 is changed in various ways as described above may be obtained by simulation or the like, and the database 50 may be created from these data.

FIG. 4 is a flowchart showing such engine load reduction processing.
First, the control device 4 acquires the current engine speed, fuel adjustment valve opening, and throttle opening, and refers to the database 50 stored in the EEPROM 42 to obtain the acquired engine speed, fuel adjustment valve opening, The current torque value, IG required voltage, and λ are acquired from the throttle opening (step S1). In this case, if the torque value, IG required voltage, and λ cannot be specified directly from the database 50, the torque is calculated by performing a complementary calculation from the operating conditions close to the current engine speed, fuel adjustment valve opening, and throttle opening. Get value, IG required voltage and λ.

  Next, the control device 4 determines whether or not the engine 10 is in an overload state based on the acquired torque value, IG request voltage, and λ (step S2). Specifically, the control device 4 determines whether or not the torque value is higher than a preset torque upper limit value, whether or not the IG request voltage is higher than a preset voltage upper limit value, and λ is greater than a preset λ lower limit value. It is determined whether or not the engine 10 is small. If any of the conditions is met, it is determined that the engine 10 is in an overload state. If none of the conditions is met, the engine 10 is determined not to be in an overload state.

If it determines with the engine 10 being in an overload state (step S2: YES), the control apparatus 4 will perform engine load reduction control which reduces the load of the engine 10. FIG.
More specifically, the control device 4 first determines that the opening degree of the expansion valve on the evaporator side (the indoor expansion valves 21a and 21b during the cooling operation and the outdoor expansion valve 14 during the heating operation) is a preset lower limit value L1. It is determined whether or not they match (step S3). And when not agree | coinciding with the lower limit L1 (when larger than the lower limit L1), the control apparatus 4 makes an expansion valve opening degree small predetermined amount (step S4). Here, the lower limit value L1 is a lower limit value of the expansion valve opening degree that does not significantly reduce the air conditioning performance, and by reducing the expansion valve opening amount in a range that does not significantly reduce the air conditioning performance, the refrigerant circulation amount is reduced, and the engine The load can be reduced.

  When the control device 4 determines that the engine 10 is not in an overload state after reducing the expansion valve opening degree, the control device 4 continues to determine whether or not the engine 10 is in an overload state by shifting to the processing of step S1. It comes to judge. For this reason, every time it is determined that the engine 10 is in an overload state, the control device 4 gradually decreases the opening of the evaporator expansion valve to gradually reduce the engine load. If it is still determined that the engine 10 is overloaded and the opening of the evaporator expansion valve is reduced to the lower limit value L1 (step S3: lower limit value L1), the process proceeds to step S5.

  In the process of step S5, the control device 4 determines whether the rotational speed of the condenser side fan (the outdoor fan 16 during the cooling operation and the indoor fans 22a and 22b during the heating operation) matches the preset upper limit value U2. If it does not match (if it is smaller than the upper limit value U2), the rotational speed of the fan is increased by a predetermined amount (step S6). Here, the upper limit value U2 is set to an allowable upper limit rotational speed of the fan or an upper limit rotational speed within which the noise from the fan is within an allowable range. Thus, by increasing the rotation speed of the fan, the condensation pressure can be improved and the load on the engine 10 can be reduced.

  After increasing the rotational speed of the fan, the control device 4 gradually increases the rotational speed of the fan every time it is determined again that the engine 10 is in an overload state by shifting to the process of step S1. If it is determined that the engine 10 is still in an overload state and the rotational speed of the fan reaches the upper limit value U2 (step S5: upper limit value L2), the control device 4 proceeds to the process of step S7.

  In the process of step S7, the control device 4 determines whether or not the engine speed matches the preset lower limit value L3. If the engine speed does not match the lower limit value L3 (if greater than the lower limit value L3), The rotational speed is reduced by a predetermined amount (step S8). Here, the lower limit L3 is set to an engine speed that does not significantly reduce the air conditioning. By reducing the engine speed in this way, the compression ratio of the compressor 11 is lowered, and the engine load can be reduced.

  After reducing the engine speed, the control device 4 proceeds to the process of step S1 to gradually reduce the engine speed every time it is determined again that the engine 10 is overloaded. When it is determined that 10 is in an overload state and the engine speed reaches the lower limit L3 (step S7: lower limit L3), the control device 4 proceeds to the process of step S9.

  In the process of step S9, the control device 4 determines whether or not the opening degree of the bypass valve 18 matches the preset upper limit value L4. If not, the control device 4 determines that the bypass valve 18 is smaller than the upper limit value L4. The opening degree of 18 is increased by a predetermined amount (step S10). Here, the upper limit value L4 is set to a bypass valve opening degree at which air-conditioning performance is not significantly reduced. By opening the bypass valve 18 in this way, the compression ratio of the compressor 11 is lowered, and the engine load can be reduced.

  After opening the bypass valve 18, the control device 4 shifts to the processing of step S <b> 1, so that the opening degree of the bypass valve 18 is gradually increased every time it is determined again that the engine 10 is in an overload state. If it is still determined that the engine 10 is overloaded, the opening of the bypass valve 18 is finally increased to the upper limit value L4.

  Thus, when the engine 10 reaches an overload state, the expansion valve opening adjustment on the evaporator side, the condenser fan speed adjustment, the engine rotation speed adjustment, and the bypass valve opening adjustment are sequentially executed. At any stage, the engine 10 can be returned from the overload state to the normal load state. However, if it is determined that the engine 10 is in an overload state even after all the stages are executed, some abnormality such as an error in the acquired engine speed, fuel adjustment valve opening, and throttle opening occurs. Therefore, the control device 4 preferably executes processing such as leaving a predetermined warning.

  By the way, the lower limit value L1, the upper limit value L2, the lower limit value L3, and the upper limit value L4 are set to an evaporator expansion valve opening, a condenser fan speed, an engine speed, and a bypass valve opening that do not significantly reduce air conditioning. However, if these values are fixed values, for example, the lower limit value L1 is set according to the case where the air conditioning load is large. If the air conditioning load is small, the expansion valve opening is lower than the lower limit value L1. Even if the value is set, the engine load can be reduced without significantly reducing the air conditioning performance, and the adjustment amount of the engine load is limited.

  Therefore, in the present embodiment, the control device 4 performs control to change the lower limit value L1, the upper limit value L2, the lower limit value L3, and the upper limit value L4 according to the current air conditioning load. Specifically, for example, the control device 4 acquires the blowing temperatures of the indoor units 2a and 2b by the temperature sensors 23a and 23b, and performs control to change the values L1 to L4 according to the blowing temperatures. For example, at the time of cooling, when the blowing temperature is 8 ° C. or lower, when it is 8 ° C. to 12 ° C., when it is 12 ° C. to 16 ° C., when it is 16 ° C. The values L1 to L4 are changed accordingly. As a result, it is possible to secure a wide range of changes in the opening of the evaporator expansion valve, the speed of the condenser fan, the engine speed, and the bypass valve opening within a range that does not significantly reduce the air conditioning performance, that is, the engine load This adjustment amount can be sufficiently secured, and the engine 10 can be more reliably avoided from being overloaded.

  As described above, in the engine-driven air conditioner 100 of this embodiment, it is determined whether or not the engine 10 is in an overload state based on the engine speed, the fuel adjustment valve opening, and the throttle opening. Thus, the engine load can be determined from the current control state of the engine 10, and the engine 10 is compared with the conventional one that determines whether the engine is in an overload state indirectly from the shaft output of the compressor. It is possible to accurately determine whether or not an overload state exists.

  Further, when the engine 10 is in an overload state, the opening degree of the evaporator side expansion valve is reduced to the lower limit value L1, the condenser fan speed is increased to the upper limit value L2, and the engine speed is decreased to the lower limit value L3. In general, priority is given to the control of the evaporator side expansion valve opening degree that is executed when the engine load is reduced by reducing the engine load in the order of increasing the opening degree of the bypass valve 18 to the upper limit value L4. Thus, the engine load can be reduced, and the engine 10 can be reliably avoided from the overload state.

  Furthermore, since each of the above values L1 to L4 is changed in real time according to the air conditioning load, it is possible to ensure a wide adjustment amount of the engine load without significantly reducing the air conditioning performance, and to ensure that the engine 10 is overloaded more reliably. Can be avoided.

Next, another embodiment will be described.
In this embodiment, as shown in FIG. 5, in addition to the indoor units 2a and 2b, two indoor units 2c and 2d having substantially the same configuration as the indoor units 2a and 2b, and an outdoor unit 1 having substantially the same configuration. The outdoor unit A includes an outdoor unit A. The outdoor unit A is configured by multi-connecting two other outdoor units B and C having different capacities in parallel.
Control units 4A, 4B, and 4C are connected to the outdoor units A, B, and C, respectively, and these control units 4A, 4B, and 4C have substantially the same function as the control unit 4 in the above-described embodiment. Have. A total control device 200 is connected to each control device 4A, 4B, 4C.

FIG. 6 shows the processing flow of this embodiment.
It is determined by the control device (determination means) 4A whether the load of the outdoor unit being operated (herein, the outdoor unit A) is in an overload state (step S21). If determined, engine load reduction control is executed by the same process as the process of steps S3 to S10 of FIG. 4 (step S22).
After execution of the engine load reduction control, it is determined whether or not the overload continues for a predetermined time (step S23). If the overload continues for a predetermined time, the outdoor unit A that is in operation has the capacity of the other outdoor unit B that is stopped. , C (step S24). Control after this comparison is controlled by the total control device 200.

If it is determined that the capacity of the outdoor unit A during operation is smaller, the operation of the outdoor unit A where the overload continues is stopped, or the capacity is greatly reduced, and the outdoor unit B or C is stopped. The operation is switched (step S25), and thereafter the operation control of the outdoor units B and C is executed (step S26).
When the capacity is set to A <B <C, first, the operation may be switched to the operation of the outdoor unit B, and the operation of the outdoor unit B may be switched to the operation of the outdoor unit C when the overload is reached. Alternatively, an overload situation may be detected, and depending on this situation, switching to the operation of the outdoor unit C may be performed at once.

If it is determined that the capacity of the outdoor unit A during operation is small, one of the stopped outdoor units B and C is operated while continuing the operation of the outdoor unit A where the overload continues (step S27). Then, it is determined whether or not the engine overload has decreased as a result of starting the operation of any of the outdoor units B and C (step S28). In this case, two units are used simultaneously until the engine overload decreases. When the above operation is executed and the overload is reduced, the outdoor unit A is returned to the single operation (step S29).
When the capacity is set to A <B <C, first, switch to the simultaneous operation of the outdoor unit B. If the simultaneous operation of the outdoor unit B is overloaded, the operation of the outdoor unit B is stopped. The operation may be switched to the simultaneous use operation of the outdoor unit C.
Alternatively, an overload situation may be detected, and depending on this situation, the simultaneous operation of the outdoor unit C may be switched at once.

  In the embodiment of FIG. 1, if the engine 10 does not escape from the overload state even if all the control steps are executed, it is assumed that there is some abnormality and the control device 4 leaves a predetermined warning as described above. In this embodiment, the air conditioning operation is continued in order to reduce the engine load by switching the operation to another outdoor unit or switching to the simultaneous use operation with another outdoor unit. Is secured.

Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, each set value and piping configuration shown in the above embodiment is not limited to this, and can be appropriately changed without departing from the spirit of the present invention.
For example, in this embodiment, the engine speed, the fuel adjustment valve opening, and the throttle opening are all acquired, and the case where it is determined whether or not the engine 10 is overloaded based on these information is illustrated. Any one of the rotational speed, the fuel adjustment valve opening, and the throttle opening may be acquired, and it may be determined based on this information whether or not the engine 10 is in an overload state. Also in this case, since it is determined whether the engine 10 is in an overload state from the actual state (control state) of the engine 10, it is conventionally determined whether the engine is indirectly overloaded from the shaft output of the compressor. It is possible to accurately determine whether or not the engine 10 is in an overload state.

  In the present embodiment, the engine speed, the fuel adjustment valve opening degree, the throttle opening degree, the torque value of the engine 10, the engine thermal efficiency, the IG required voltage, the fuel gas flow rate, and the storage means for mapping and storing λ are stored. However, the engine thermal efficiency and the fuel gas flow rate may be omitted, and the engine speed and the fuel adjustment valve are opened in advance using a neural network that is an information processing mechanism created by mimicking the structure of the human brain. Torque, throttle opening, torque value, IG required voltage and λ by learning experimental data obtained from λ, torque from all or any of engine speed, fuel adjustment valve opening and throttle opening It is good also as a structure provided with the memory | storage means to memorize | store the calculation formula which calculates at least any one of a value, IG request voltage, and (lambda). According to this, the usage amount of the EEPROM 42 can be suppressed.

  In the present embodiment, when the engine 10 is in an overload state, the expansion valve opening adjustment on the evaporator side, the condenser fan speed adjustment, the engine rotation speed adjustment, and the bypass valve opening adjustment are sequentially executed. However, it is not always necessary to perform all these engine load reduction controls, and only one or a plurality of controls may be performed.

It is a figure which shows the structure of the engine drive type air conditioning apparatus concerning this embodiment. It is a block diagram which shows the structure of a control apparatus. It is a figure explaining a database. It is a flowchart which shows an engine load reduction process. It is a figure which shows the structure of the air conditioning apparatus concerning another embodiment. It is a flowchart which shows an engine load reduction process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Engine drive type air conditioner 1 Outdoor unit A, B, C Outdoor unit 2a, 2b Indoor unit 4 Control apparatus 4A, 4B, 4C Control apparatus 5 Operation part 10 Engine 11 Compressor 13 Outdoor heat exchanger 14 Outdoor expansion valve 17 Bypass pipe 18 Bypass valve 20a, 20b Indoor heat exchanger 21a, 21b Indoor expansion valve 22a, 22b Indoor fan 31 Engine fuel supply device 50 Database 200 Total control device

Claims (7)

An engine that variably controls the rotational speed of the engine according to the air conditioning load and circulates the refrigerant discharged from the compressor driven by the engine between the outdoor heat exchanger and the indoor heat exchanger to perform the air conditioning operation In the drive type air conditioner,
Measure the torque value, ignition required voltage, and excess air ratio of the engine when the fuel adjustment valve opening and the throttle opening are adjusted so that the engine rotates at a predetermined speed while torque is applied to the engine. The measured value when this measurement is performed a plurality of times by changing the torque applied to the engine and the engine speed, and the engine speed, fuel adjustment valve opening, and throttle opening at each measurement Storage means for storing;
Rotational speed of the engine, fuel adjusting valve opening degree, and obtains the throttle opening degree, the torque value of the engine by referring to the information stored in the storage means based on the acquired information, the ignition demand voltage and an excess air ratio It was identified based on a comparison of the preset value with a specific value, a determination unit configured to determine whether the engine is overloaded,
An engine-driven air conditioner comprising: control means for performing engine load reduction control for reducing the load of the engine when it is determined that the engine is in an overload state. When determining that the engine is in an overload state, the control means adjusts an opening degree of an expansion valve corresponding to a heat exchanger functioning as an evaporator among the outdoor heat exchanger and the indoor heat exchanger, Among heat exchangers and indoor heat exchangers, adjustment of the rotational speed of a cooling fan for heat exchange functioning as a condenser, adjustment of the engine speed, or bypass provided between the refrigerant high-pressure part and the refrigerant low-pressure part claim 1 Symbol placing the engine driving type air conditioner and performing at least one of adjustment of the opening degree of the bypass valve of the tube. The control means includes a lower limit value at the time of adjusting the opening degree of an expansion valve corresponding to the heat exchanger functioning as the evaporator, an upper limit value at the time of adjusting the rotational speed of a cooling fan for heat exchange functioning as the condenser, the engine The engine-driven air conditioner according to claim 2 , wherein a lower limit value at the time of adjusting the rotational speed or an upper limit value at the time of adjusting the opening degree of the bypass valve is changed according to an air conditioning load. A plurality of outdoor units each having the compressor driven by the engine and the outdoor heat exchanger are provided, and in the outdoor unit in operation, even if the control by the determination unit and the control unit is executed, the engine overload state The engine-driven air conditioner according to any one of claims 1 to 3 , wherein when the operation is continued, another outdoor unit that is stopped is operated to reduce the engine load. A plurality of outdoor units having different capacities having the compressor driven by the engine and the outdoor heat exchanger are provided, and the control by the determination means and the control means is executed in the operating outdoor unit having a small capacity. However, when the engine overload state is continued, the engine-driven air conditioner according to any one of claims 1 to 3 is switched to an operation of an outdoor unit having a large capacity. A total control device for controlling a control device provided in each of the plurality of outdoor units, and even if the total control device is controlled by the determination means and the control means, the engine overload state is The engine-driven air conditioner according to claim 4 or 5 , wherein the control is executed when the operation is continued. An engine that variably controls the rotational speed of the engine according to the air conditioning load and circulates the refrigerant discharged from the compressor driven by the engine between the outdoor heat exchanger and the indoor heat exchanger to perform the air conditioning operation In the control method of the drive type air conditioner,
Measure the torque value, ignition required voltage, and excess air ratio of the engine when the fuel adjustment valve opening and the throttle opening are adjusted so that the engine rotates at a predetermined speed while torque is applied to the engine. The measured value when this measurement is performed a plurality of times by changing the torque applied to the engine and the engine speed, and the engine speed, fuel adjustment valve opening, and throttle opening at each measurement are as follows: In the state stored in the storage means in advance,
Rotational speed of the engine, fuel adjusting valve opening degree, and obtains the throttle opening degree, the torque value of the engine by referring to the information stored in the storage means based on the acquired information, the ignition demand voltage and an excess air ratio identify, based on a comparison of the preset value with a specific value, the engine is controlled to determine whether or not the overload state in accordance with the air conditioning load,
If it determines with the said engine being in an overload state, the engine load reduction control which reduces the load of the said engine is performed. The control method of the engine drive type air conditioning apparatus characterized by the above-mentioned.

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