Hybrid air conditioning system

Abstract

To downsize a hybrid air conditioning system.SOLUTION: A hybrid air conditioning system includes a refrigerant circuit provided with an indoor heat exchanger and an outdoor heat exchanger, a motor generator 21 in which an MG shaft gear 232 is attached to a rotation shaft 211, an engine 20 in which an EG shaft gear 231 is attached to an output shaft 201, a compressor in which CP shaft gears 233a, 233b are provided in input shafts 221a, 221b and which is operated by a driving force supplied to the input shafts 221a, 221b to circulate refrigerant in the refrigerant circuit, and the CP shaft gears 233a, 233b which are coaxially attached to the input shafts 221a, 221b of compressors 22a, 22b and are coordinated with the EG shaft gear 231 to transmit power. The MG shaft gear 232, the EG shaft gear 231, and the CP shaft gears 233a, 233b are disposed on the same plane.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hybrid air conditioning system. [Background technology]

[0002] Patent Documents 1 and 2 disclose hybrid air conditioning systems equipped with an engine and a motor as driving power sources for a compressor that compresses a refrigerant. The hybrid air conditioning system described in Patent Document 1 (referred to in Patent Document 1 as a hybrid refrigerant compression heat transfer device) is configured so that driving power is transmitted from either the engine or the motor to the compressor via a switching coupling device. Furthermore, the hybrid air conditioning system described in Patent Document 2 (referred to in Patent Document 2 as a heat pump system) is configured so that driving power is transmitted from the engine and the motor to the compressor via a pulley belt.

[0003] However, there is a demand for such hybrid air conditioning systems to be made smaller (space-saving).However, the hybrid air conditioning systems described in Patent Documents 1 and 2 are difficult to make smaller.

[0004] That is, the switching coupling device of the hybrid air conditioning system described in Patent Document 1 includes a bevel gear provided on the input shaft of the compressor, and this bevel gear is configured to mesh with both a bevel gear provided on the output shaft of the engine and a bevel gear provided on the output shaft of the motor. The engine and the motor are arranged to face each other via the coupling switching device, and the compressor is arranged to the side of the engine and the motor. This makes it difficult to arrange the engine, motor, and compressor close to each other, making it difficult to reduce the size of the hybrid air conditioning system.

[0005] Furthermore, in the hybrid air conditioning system described in Patent Document 2, the engine, motor, and two compressors are positioned offset from one another when viewed in the axial direction of the engine output shaft. This increases the size of the hybrid air conditioning system when viewed in the axial direction of the engine output shaft, making it difficult to miniaturize. Furthermore, in the hybrid air conditioning system described in Patent Document 2, the motor output is input to the engine output shaft via a pulley and a belt. In this case, in order to maintain the motor rotation speed and the engine rotation speed within their respective appropriate ranges, the diameters of the motor-side pulley connected to the motor output shaft and the engine-side pulley connected to the engine output shaft must be appropriately adjusted. When transmitting driving force from the motor side to the engine side, if the diameter of the motor-side pulley is approximately half the diameter of the engine-side pulley or less, the frictional force is lower than the driving force due to the small contact area between the motor-side pulley and the belt, resulting in belt slippage and reduced transmission efficiency of the power output from the motor. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-132594 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-225556 Summary of the Invention

[0007] (Problem to be solved by the invention) In view of the above circumstances, one object of the present invention is to reduce the size (space) of a hybrid air conditioning system that includes an engine and a motor that supply driving force to a compressor that compresses a refrigerant.

[0008] (Means for solving the problem) In order to achieve the above object, the hybrid air conditioning system according to the present invention comprises: a refrigerant circuit including an indoor heat exchanger and an outdoor heat exchanger; a motor that generates driving force when supplied with power; a motor gear attached coaxially to a motor shaft that is an output shaft of the motor; an engine that generates driving force when fuel is supplied; an engine gear attached coaxially to an engine shaft which is an output shaft of the engine; a compressor that operates when a driving force output from at least one of the motor and the engine is transmitted to an input shaft, and that circulates a refrigerant through the refrigerant circuit; a compressor gear that is coaxially attached to the input shaft of the compressor and that is linked to the engine gear so as to be able to transmit driving force; Equipped with the engine gear, the motor gear, and the input shaft of the compressor are linked together so as to be able to transmit power; The motor gear, the engine gear, and the compressor gear are arranged on the same plane.

[0009] According to the present invention, the dimension of the power transmission mechanism including the motor gear, engine gear, and compressor gear in the direction parallel to the engine output shaft can be reduced, which reduces the distance between the engine and the motor and the distance between the engine and the compressor, thereby reducing the dimension of the hybrid air conditioning system in the direction parallel to the engine output shaft. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a hybrid air conditioning system. [Figure 2] FIG. 2 is a diagram showing the configuration of a power unit including a power transmission mechanism. [Figure 3] FIG. 3 is a diagram showing the configuration of a power unit including a power transmission mechanism. [Figure 4] FIG. 4 is a diagram showing the configuration of a power unit according to a first modified example. [Figure 5] FIG. 5 is a diagram showing the configuration of a power unit according to a second modified example. [Figure 6]FIG. 6 is a diagram showing the configuration of a power unit according to a third modified example. [Figure 7] FIG. 7 is a diagram showing the configuration of a power unit according to a fourth modified example. [Figure 8] FIG. 8 is a diagram showing the configuration of a power unit according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] A hybrid air conditioning system according to an embodiment of the present invention will be described below. In the following description, the "hybrid air conditioning system" may be abbreviated as "air conditioning system."

[0012] <Air conditioning system configuration> Fig. 1 is a diagram showing the configuration of an air conditioning system 10. As shown in Fig. 1, the air conditioning system 10 includes an outdoor unit 11 installed outdoors, a plurality of indoor units 12 installed indoors, and a refrigerant circuit 13 provided across the outdoor unit 11 and the indoor units 12. The outdoor unit 11 of the air conditioning system 10 includes a power unit 14A, a coolant circuit 15, a control device 16, and a battery 17. The power unit 14A includes one engine 20, one motor generator 21, two compressors (a first compressor 22a and a second compressor 22b), and a power transmission mechanism 23A.

[0013] The engine 20 is a driving force source for the two compressors 22a, 22b. An output shaft 201 of the engine 20 is an example of an engine shaft of the present invention. A gas engine that generates driving force by burning gaseous fuel such as fuel gas is used as the engine 20. The engine 20 operates (outputs driving force) using gas (e.g., city gas) supplied from outside the air conditioning system 10 as fuel. The engine 20 is provided with a water jacket (not shown). This water jacket is provided on a coolant circuit 15 (which will be described later) (it can also be said that the water jacket forms part of the coolant circuit 15). The power unit 14A is provided with a starter motor (not shown) that operates using power from the battery 17, and the engine 20 is configured to be able to start by this starter motor.

[0014] The motor generator 21 is an example of a motor of the present invention. The rotating shaft 211 of the motor generator 21 is an example of an output shaft of a motor of the present invention. The motor generator 21 functions as a driving power source for two compressors 22a and 22b (described later) and as a generator that generates electricity using the driving power output by the engine 20. The motor generator 21 is electrically connected to the system power supply and the battery 17, and when functioning as a motor (driving power source), it can operate (output driving power) using power supplied from the system power supply and power supplied from the battery 17. When functioning as a generator, it can charge the generated power into the battery 17.

[0015] The two compressors (first compressor 22a and second compressor 22b) include input shafts 221a and 221b, and are configured to operate when a driving force is input to the input shafts 221a and 221b, thereby circulating a refrigerant through the refrigerant circuit 13. Both of the two compressors 22a and 22b are driven (operated) by a driving force output from at least one of the engine 20 and the motor generator 21. Both of the two compressors 22a and 22b include a refrigerant suction port 222 and a refrigerant discharge port 223, and are configured to draw in a refrigerant through the refrigerant suction port 222, compress the drawn refrigerant, and discharge it from the refrigerant discharge port 223. The refrigerant suction port 222 and the refrigerant discharge port 223 of each of the two compressors 22a and 22b are connected to the refrigerant circuit 13 (it can also be said that each of the two compressors 22a and 22b forms a part of the refrigerant circuit 13). The configuration of the two compressors 22a and 22b is not particularly limited, and a conventionally known configuration can be applied.

[0016] The power transmission mechanism 23A is configured to be able to transmit the driving force output by the engine 20 to the two compressors 22a, 22b. The power transmission mechanism 23A is also configured to be able to transmit the driving force output by the motor generator 21 to the two compressors 22a, 22b. The power transmission mechanism 23A is also configured to be able to transmit the driving force output by the engine 20 to the motor generator 21. The configuration of the power transmission mechanism 23A will be described in detail later.

[0017] The battery 17 is electrically connected to the motor generator 21 and a system power supply (not shown). The battery 17 can be charged with power supplied from the system power supply, and can also be charged with power generated by the motor generator 21. The battery 17 can also supply operating power to each part of the air conditioning system 10, including the power unit 14A and the control device 16.

[0018] The control device 16 is a device that controls each part of the air conditioning system 10, including the power unit 14A. The control device 16 is equipped with a computer that includes a CPU, ROM, and RAM. The ROM of the computer of the control device 16 stores a computer program for controlling each part of the air conditioning system 10 in advance. The CPU of the computer of the control device 16 then reads this computer program from the ROM, expands it into RAM (using the RAM as a work area), and executes it. This realizes control of the air conditioning system 10.

[0019] The refrigerant circuit 13 is configured to allow refrigerant to circulate. The refrigerant circuit 13 includes a refrigerant path 41 through which the refrigerant can flow, and an indoor heat exchanger 47 and an outdoor heat exchanger 45 provided on the refrigerant path 41. The coolant circuit 15 is configured to allow coolant to circulate for cooling the engine 20 and the motor generator 21. The configuration of the refrigerant circuit 13 and the coolant circuit 15 will be described later.

[0020] 2, in the power unit 14A, the engine 20 is disposed on one side of the gear train of the power transmission mechanism 23A (more specifically, on one side in a direction parallel to the rotational axes of the gears), and the motor generator 21 and the two compressors 22a, 22b are disposed on one side opposite to the side on which the engine 20 is disposed. In other words, the engine 20, the motor generator 21, and the two compressors 22a, 22b are disposed on opposite sides of the power transmission mechanism 23A in a direction parallel to the rotational axes of the gears. In yet other words, the engine 20, the motor generator 21, and the two compressors 22a, 22b are disposed so as to face each other across the power transmission mechanism 23A.

[0021] <Power transmission mechanism configuration> Next, the configuration of the power transmission mechanism 23A will be described. Figures 2 and 3 are schematic diagrams showing the configuration of the power unit 14A including the power transmission mechanism 23A. Note that Figure 2 is a view seen in a direction perpendicular to the output shaft 201 of the engine 20, and Figure 3 is a view seen in a direction parallel to the output shaft 201 of the engine 20. Note that in Figure 3, the outlines of the engine 20, the motor generator 21, and the two compressors 22a, 22b are shown with dashed lines.

[0022] 2 and 3, the power transmission mechanism 23A includes one EG shaft gear 231, one MG shaft gear 232, two CP shaft gears 233a and 233b (i.e., the same number as the compressors 22a and 22b), one CT gear 234, one EG shaft clutch 235, two CP shaft clutches 236a and 236b (i.e., the same number as the compressors 22a and 22b), a damper 237, and a housing 238. The EG shaft gear 231 is an example of an engine gear of the present invention, the MG shaft gear 232 is an example of a motor gear of the present invention, the CP shaft gears 233a and 233b are examples of compressor gears of the present invention, and the CT gear 234 is an example of a counter gear of the present invention. The one MG shaft gear 232, the two CP shaft gears 233a and 233b, and the one CT gear 234 form a gear train that is linked to each other so as to be able to transmit driving force. The gears of the power transmission mechanism 23A are rotatably housed in a housing 238.

[0023] The EG shaft gear 231 is a gear provided coaxially on the output shaft 201 of the engine 20. The MG shaft gear 232 is a gear provided coaxially on the rotating shaft 211 of the motor generator 21. The two CP shaft gears 233a, 233b are gears provided coaxially on the input shafts 221a, 221b of the two compressors 22a, 22b, respectively. The CT gear 234 is a counter gear interposed between the EG shaft gear 231 and the two CP shaft gears 233a, 233b. The CT gear 234 is an idle gear, and is rotatably supported on the housing 238 via its rotating shaft (hereinafter referred to as the CT shaft 239). As shown in FIG. 3, the EG shaft gear 231 and the MG shaft gear 232 mesh directly, the EG shaft gear 231 and the CT gear 234 mesh directly, and the CT gear 234 and the two CP shaft gears 233a and 233b mesh directly.

[0024] The output shaft 201 of the engine 20, the rotary shaft 211 of the motor generator 21, and the input shafts 221a and 221b of the two compressors 22a and 22b are all parallel to one another. The EG shaft gear 231, the MG shaft gear 232, the CT gear 234, and the two CP shaft gears 233a and 233b are all parallel shaft gears (sometimes called cylindrical gears). These gears may be spur gears or helical gears.

[0025] 3, the EG shaft gear 231, the MG shaft gear 232, the CT gear 234, and the two CP shaft gears 233a and 233b are arranged on a common imaginary plane P extending in a direction perpendicular to their rotation shafts 211. More specifically, the EG shaft gear 231, the MG shaft gear 232, the CT gear 234, and the two CP shaft gears 233a and 233b are arranged so that their face width centers (centers in the axial direction) are located on a common plane P extending in a direction perpendicular to their rotation shafts 211. The imaginary plane P is a plane perpendicular to the paper surface in FIG. 2, and is a plane parallel to the paper surface in FIG. 3.

[0026] Between the EG shaft gear 231 and the main body of the engine 20, a damper 237 and an EG shaft clutch 235 are arranged in this order from the side closest to the main body of the engine 20. Therefore, it can also be said that "the EG shaft gear 231 is attached to the output shaft 201 of the engine 20 via the damper 237 and the EG shaft clutch 235." The damper 237 is a damping device for absorbing vibrations and noise of the engine 20. The configuration of the damper 237 is not limited, but the configurations disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-71731 or Japanese Patent Application Laid-Open No. 2007-16855 can be applied. The EG shaft clutch 235 is configured to be able to interrupt the transmission of power between the engine 20 and the EG shaft gear 231 under the control of the control device 16. The configuration of the EG shaft clutch 235 is not particularly limited, and various electromagnetic clutches can be applied.

[0027] The two CP shaft clutches 236a, 236b are disposed between the CP shaft gears 233a, 233b and the main bodies of the compressors 22a, 22b, respectively. Therefore, it can also be said that "the CP shaft gears 233a, 233b are attached to the input shafts 221a, 221b of the compressors 22a, 22b via the CP shaft clutches 236a, 236b." The two CP shaft clutches 236a, 236b are configured to be able to connect and disconnect the transmission of power between the CP shaft gears 233a, 233b and the main bodies of the compressors 22a, 22b under the control of the control device 16. The configuration of the CP shaft clutches 236a, 236b is not particularly limited, and various electromagnetic clutches can be applied.

[0028] As shown in FIG. 3 , the output shaft 201 of the engine 20 (in other words, the rotational shaft of the EG shaft gear 231), the rotational shaft 211 of the motor generator 21 (in other words, the rotational shaft of the MG shaft gear 232), the input shafts 221a and 221b of the two compressors 22a and 22b (in other words, the rotational shafts of the CP shaft gears 233a and 233b), and the CT shaft 239 are all located inside the outline of the engine 20 (more specifically, the outlines (contours) of the crankcase, cylinder, and cylinder head of the engine 20) when viewed in a direction parallel to the output shaft 201 of the engine 20. With this configuration, it is possible to reduce the size of the outline of the power unit 14A when viewed in a direction parallel to the output shaft 201 of the engine 20. This reduces the space required to arrange the power unit 14A, thereby enabling the air conditioning system 10, and in particular the outdoor unit 11, to be reduced in size.

[0029] In addition, it is preferable that the MG shaft gear 232, the CT gear 234, and the two CP shaft gears 233a, 233b are arranged on opposite sides of the EG shaft gear 231 in the longitudinal direction of the engine 20 when viewed in a direction parallel to the output shaft 201 of the engine 20. In Fig. 2 and Fig. 3, the vertical direction is the longitudinal direction of the engine 20, and a configuration is shown in which the MG shaft gear 232 is arranged above the EG shaft gear 231, and the CT gear 234 and the two CP shaft gears 233a, 233b are arranged below the EG shaft gear 231. With this configuration, the motor generator 21 and the two compressors 22a, 22b can be arranged side by side in a direction substantially parallel to the longitudinal direction of the engine 20, and therefore, when viewed in a direction parallel to the output shaft 201 of the engine 20, the portions of the motor generator 21 and the two compressors 22a, 22b that protrude outside the outline of the engine 20 can be made small. In other words, the dimensions of the power unit 14A in the "longitudinal direction of the engine 20 and the direction perpendicular to the output shaft 201" can be reduced.

[0030] In this case, the output shaft 201 of the engine 20, the rotation shaft 211 of the motor generator 21, and the CT shaft 239 of the CT gear 234 are preferably arranged to align on a single imaginary straight line L that is approximately parallel to the longitudinal direction of the engine 20. The two CP shaft gears 233a, 233b are preferably arranged at positions that are line-symmetrical with respect to the imaginary straight line L when viewed in a direction parallel to the output shaft 201 of the engine 20. This configuration enhances the effect of reducing the dimensions of the power unit 14A in the "longitudinal direction of the engine 20 and the direction perpendicular to the output shaft 201." Therefore, the effect of reducing the size of the air conditioning system 10 can be enhanced.

[0031] Furthermore, as in this embodiment, if the EG shaft gear 231, the MG shaft gear 232, the CP shaft gears 233a, 233b, and the CT gear 234 are all parallel shaft gears (cylindrical gears) and are configured to be arranged on the same plane P, it is possible to reduce the distance between the engine 20 and the motor generator 21 and the distance between the two compressors 22a, 22b of the engine 20. Therefore, it is possible to reduce the "dimension in the direction parallel to the output shaft 201 of the engine 20" of the air conditioning system 10, thereby enhancing the effect of miniaturizing the air conditioning system 10.

[0032] Furthermore, the two compressors 22a, 22b and the motor generator 21 are disposed opposite the engine 20 via the gear train of the power transmission mechanism 23A (in other words, on opposite sides of the gear train). This configuration allows the power unit 14A to be miniaturized (in other words, the space required for the power unit 14A) to which the power transmission mechanism 23A is applied. That is, if one of the two compressors 22a, 22b and the motor generator 21 is disposed on the same side as the engine 20, one of the compressors 22a, 22b and the motor generator 21 is disposed adjacent to the engine 20 when viewed in a direction parallel to the output shaft 201 of the engine 20. This increases the external dimensions of the power unit 14A when viewed in a direction parallel to the output shaft 201 of the engine 20. However, this arrangement does not reduce the dimension of the engine 20 in a direction parallel to the output shaft 201. This increases the size of the power unit 14A (in other words, the space required for the power unit 14A).

[0033] In contrast, if the two compressors 22a, 22b and the motor generator 21 are arranged on the same side as seen from the gear train but on the opposite side from the engine 20, the compressors 22a, 22b and the motor generator 21 are not arranged adjacent to the engine 20. This makes it possible to prevent or suppress an increase in the dimension of the power unit 14A as viewed in a direction parallel to the output shaft 201 of the engine 20.

[0034] The power transmission mechanism 23A is configured to transmit power using a gear train, which can improve the power transmission efficiency compared to a configuration that transmits power using a combination of pulleys and belts.

[0035] That is, in a configuration using pulleys and belts, the ratio between the diameter of the pulley provided on output shaft 201 of engine 20 and the diameter of the pulleys provided on input shafts 221a, 221b of two compressors 22a, 22b is determined according to the relationship between the rotation speed of output shaft 201 of engine 20 and the rotation speed of input shafts 221a, 221b of two compressors 22a, 22b. Also, the ratio between the diameter of the pulley provided on rotating shaft 211 of motor generator 21 and the diameter of the pulleys provided on input shafts 221a, 221b of two compressors 22a, 22b is determined according to the relationship between the rotation speed of rotating shaft 211 of motor generator 21 and the rotation speed of input shafts 221a, 221b of two compressors 22a, 22b when motor generator 21 functions as a motor.

[0036] When attempting to achieve an appropriate relationship between the rotation speed of output shaft 201 of engine 20 and the rotation speed of input shafts 221a, 221b of two compressors 22a, 22b, and between the rotation speed of rotating shaft 211 of motor generator 21 and the rotation speed of input shafts 221a, 221b of two compressors 22a, 22b when motor generator 21 functions as a motor, the diameter of the pulley provided on rotating shaft 211 of motor generator 21 may become smaller than the diameter of the pulley provided on output shaft 201 of engine 20. For this reason, in this case, the contact angle of the belt of the pulley provided on rotating shaft 211 of motor generator 21 becomes too small, making slippage more likely to occur and reducing the efficiency of power transmission. In particular, the shorter the distance between the pulley of the output shaft 201 of the engine 20 and the pulley of the rotating shaft 211 of the motor generator 21 is made in order to downsize the air conditioning system 10, the smaller the contact angle of the belt of the pulley provided on the rotating shaft 211 of the motor generator 21 becomes, making slippage more likely to occur (or increasing the slippage).

[0037] In contrast, the power transmission mechanism 23A according to this embodiment uses a gear train to transmit power, so slippage does not occur. This prevents a decrease in power transmission efficiency. In particular, even if the output shaft 201 of the engine 20 and the rotating shaft 211 of the motor generator 21 are brought closer to each other for the purpose of downsizing, the efficiency of power transmission does not decrease. In other words, the air conditioning system 10 can be downsized without a decrease in power transmission efficiency.

[0038] Furthermore, when a gear train is applied to the power transmission mechanism 23A, the dimension of the power unit 14A in the direction parallel to the output shaft 201 of the engine 20 can be reduced compared to a configuration using pulleys and a belt. That is, in the configuration disclosed in JP 2012-225556 A, two pulleys are attached to the output shaft of the engine or the input shaft of one of the compressors so as to be aligned in the axial direction, so the dimension of the power transmission mechanism in the direction parallel to the output shaft of the engine is large. In contrast, when a gear train is applied as in this embodiment, both the MG shaft gear 232 and the CT gear 234 can be meshed with one EG shaft gear 231, so the dimension of the power transmission mechanism 23A in the direction parallel to the output shaft 201 of the engine 20 can be reduced.

[0039] Furthermore, a configuration in which a gear train is applied to power transmission mechanism 23A makes maintenance easier than a configuration in which a combination of pulleys and belts is applied. That is, a configuration in which a combination of pulleys and belts is applied requires the attachment and detachment of belts during maintenance of two compressors 22a, 22b or motor generator 21. In contrast, a configuration in which a gear train is applied does not require such work.

[0040] In addition, in this embodiment, a damper 237 is provided between the output shaft 201 of the engine 20 and the rotating shaft 211 of the motor generator 21. With this configuration, vibrations transmitted from the engine 20 to the EG shaft gear 231 are reduced, thereby reducing vibrations in the gear train of the power transmission mechanism 23A and noise generated in the gear train of the power transmission mechanism 23A. Furthermore, since the damper 237 is provided at a position closer to the main body of the engine 20 than the EG shaft gear 231, vibrations transmitted from the engine 20 to other parts of the power unit 14A and other parts of the air conditioning system 10 to which the power unit 14A is applied can be reduced. Therefore, the effect of reducing noise and vibrations generated in the air conditioning system 10 can be enhanced.

[0041] Furthermore, if a damper 237 is provided between the output shaft 201 of the engine 20 and the rotating shaft 211 of the motor generator 21, when the engine 20 operates and the motor generator 21 operates as a motor (described later), the difference in rotation speed between the engine 20 and the motor generator 21 is absorbed by the damper 237. This reduces vibration and noise of the air conditioning system 10, and also reduces the load on the engine 20 and the motor generator 21.

[0042] Furthermore, with a configuration in which the CT gear 234 is interposed between the EG shaft gear 231 and the two CP shaft gears 233a, 233b, the rotation direction of the driving force transmitted from the engine 20 to the two compressors 22a, 22b can be adjusted. That is, the rotation direction of the driving force output by the engine 20 is generally one direction that is determined in advance, and the rotation directions of the input shafts 221a, 221b of the two compressors 22a, 22b are also one direction that is determined in advance. For this reason, if the rotation direction of the driving force output by the engine 20 is the same as the rotation direction of the input shafts 221a, 221b of the two compressors 22a, 22b in a state in which the engine 20 and the two compressors 22a, 22b are arranged to face each other, the two compressors 22a, 22b cannot be driven with a configuration in which the EG shaft gear 231 is directly meshed with the two CP shaft gears 233a, 233b. Therefore, in such a case, by interposing one CT gear 234 between the EG shaft gear 231 and the two CP shaft gears 233a, 233b, the two compressors 22a, 22b can be driven by the driving force output by the engine 20.

[0043] However, in a configuration in which the engine 20 and the two compressors 22a, 22b are arranged to face each other, if the rotation direction of the driving force output by the engine 20 and the rotation direction of the input shafts 221a, 221b of the two compressors 22a, 22b are opposite to each other, the EG shaft gear 231 and the CP shaft gears 233a, 233b may be directly meshed with each other. In this case, the power transmission mechanism 23A may be provided with two CT gears 234. In this case, a configuration is applied in which the two CT gears 234 directly mesh with each other, one of the two CT gears 234 directly meshes with the EG shaft gear 231, and the other CT gear 234 directly meshes with the two CP shaft gears 233a, 233b.

[0044] <Basic operation of air conditioning systems> Next, we will explain the basic operation of the air conditioning system 10. When power is supplied from a system power supply (not shown) and gas is supplied from outside the air conditioning system 10, the control device 16 determines whether one or both of the two compressors 22a, 22b are driven by the driving force of the engine 20, one or both of the two compressors 22a, 22b are driven by the driving force of the motor generator 21, or one or both of the two compressors 22a, 22b are driven by the driving force of the engine 20 and the motor generator 21, depending on whether predetermined conditions are met.

[0045] When both of the two compressors 22a, 22b are driven by the driving force of the engine 20, the control device 16 maintains the EG shaft clutch 235 and the two CP shaft clutches 236a, 236b in a "state that permits power transmission" (hereinafter, sometimes referred to as a "connected state"). Therefore, the driving force output by the engine 20 is transmitted to each of the two compressors 22a, 22b via the damper 237, the EG shaft clutch 235, the EG shaft gear 231, the CT gear 234, the two CP shaft gears 233a, 233b, and the two CP shaft clutches 236a, 236b. In this case, the control device 16 does not operate the motor generator 21 as either a driving force source or a generator. Therefore, in this case, the driving force is transmitted to the motor generator 21 via the EG shaft gear 231 and the MG shaft gear 232 (the rotary shaft 211 of the motor generator 21 rotates), but the motor generator 21 rotates idly without generating electricity.

[0046] When both of the two compressors 22a, 22b are driven by the driving force of the motor generator 21, the control device 16 maintains the EG shaft clutch 235 in a "state that does not allow power transmission" (hereinafter, sometimes referred to as a "disconnected state") and maintains the two CP shaft clutches 236a, 236b in an engaged state. Therefore, the driving force output by the motor generator 21 is transmitted to each of the two compressors 22a, 22b via the MG shaft gear 232, the EG shaft gear 231, the CT gear 234, the two CP shaft gears 233a, 233b, and the two CP shaft clutches 236a, 236b. In this case, the control device 16 does not operate the engine 20. Since the EG shaft clutch 235 is in the disconnected state, the driving force of the motor generator 21 is not transmitted to the output shaft 201 of the engine 20.

[0047] Furthermore, when the air conditioning load (sometimes referred to as the heating and cooling load) is high, the control device 16 operates the engine 20 and also operates the motor generator 21 as a motor. As a result, the two compressors 22a and 22b are driven by the driving forces of the engine 20 and the motor generator 21.

[0048] On the other hand, when the air conditioning load is low, one of the two compressors 22a, 22b is alternately driven at a predetermined cycle by the driving force of either the engine 20 or the motor generator 21. That is, the control device 16 operates one of the engine 20 and the motor generator 21 depending on whether a predetermined condition is met. When the engine 20 is operated, the control device 16 maintains the EG shaft clutch 235 in an engaged state, and when the motor generator 21 is operated, the control device 16 maintains the EG shaft clutch 235 in a disengaged state. The control device 16 also alternately switches the two CP shaft clutches 236a, 236b between an engaged state and a disengaged state at a predetermined cycle. That is, the control device 16 alternately switches between a state in which the first compressor 22a is driven and the second compressor 22b is not driven and a state in which the second compressor 22b is driven and the first compressor 22a is not driven at a predetermined cycle.

[0049] If the supply of gas from the outside continues but the supply of power from the grid power supply is stopped (i.e., if the grid power supply is interrupted), the control device 16 operates using power supplied from the battery 17. The control device 16 drives one or both of the two compressors 22a, 22b using the driving force of the engine 20, and also operates the motor generator 21 as a power generator using the driving force of the engine 20. The power generated by the motor generator 21 is charged to the battery 17. If the supply of power from the grid power supply is stopped while the air conditioning system 10 is in operation, the control device 16 temporarily stops the operation of the engine 20 and the motor generator 21. The control device 16 then starts the engine 20 by operating a starter motor (not shown) using the power from the battery 17. After the engine 20 starts operating, the control device 16 operates the motor generator 21 as a power generator. In this way, the air conditioning system 10 can start operating even if the supply of power from the grid power supply is stopped.

[0050] When the supply of gas from outside the air conditioning system 10 is stopped (i.e., when the gas supply is shut off) while the supply of power from the system power supply continues, the control device 16 operates the motor generator 21 as a motor (driving force source) using the power supplied from the system power supply, and drives one or both of the two compressors 22a, 22b using the driving force output by the motor generator 21.

[0051] In this way, when the air conditioning system 10 is configured to include the engine 20 and the motor generator 21 as the driving power sources for the two compressors 22a, 22b, operation (cooling operation and heating operation) can be continued even if the supply of either gas or electricity from outside the air conditioning system 10 is stopped. Therefore, the livability of a facility (building, etc.) to which the air conditioning system 10 is applied can be improved.

[0052] The carbon dioxide emission coefficient can be used as a condition for selecting whether to drive one or both of the two compressors 22a, 22b with the driving force of the engine 20 or to drive one or both of the two compressors 22a, 22b with the driving force of the motor generator 21. Specifically, the control device 16 compares the carbon dioxide emission coefficient when one or both of the two compressors 22a, 22b are driven with the driving force output by the engine 20 with the carbon dioxide emission coefficient when one or both of the two compressors 22a, 22b are driven with the driving force output by the motor generator 21, and drives one or both of the two compressors 22a, 22b with the lower driving force source. This configuration can reduce carbon dioxide emissions caused by operation of the air conditioning system 10.

[0053] Furthermore, the power usage status of the grid power supply can be used as a condition for the selection. Specifically, the control device 16 monitors the power usage status of the entire facility (e.g., the entire building) to which the air conditioning system 10 is applied, and when the power usage of the entire facility approaches the allowable upper limit, the control device 16 drives one or both of the two compressors 22a, 22b using the driving force of the engine 20 alone, and operates the motor generator 21 as a generator. With this configuration, the power consumption of the grid power supply by the air conditioning system 10 can be reduced or eliminated, thereby alleviating the degree of pressure on the power usage status of the grid power supply.

[0054] Furthermore, when the CP shaft clutches 236a and 236b are provided on the input shafts 221a and 221b of the two compressors 22a and 22b, respectively, the two compressors 22a and 22b can be alternately driven as described above. This reduces the drive time of each compressor 22a and 22b, thereby extending the lifespan of the compressors 22a and 22b. Furthermore, when the CP shaft clutches 236a and 236b are provided on the input shafts 221a and 221b of the two compressors 22a and 22b, respectively, if one of the compressors 22a and 22b malfunctions, the driving force is prevented from being transmitted to that compressor. By preventing the driving force from being transmitted to the malfunctioning compressor 22a or 22b, the driving force is prevented from being consumed by the malfunctioning compressor 22a or 22b, thereby preventing or suppressing unnecessary energy consumption.

[0055] Furthermore, if the damper 237 is provided on the output shaft 201 of the engine 20, when the engine 20 operates and the motor generator 21 operates as a motor, the damper 237 absorbs the difference in rotation speed between the engine 20 and the motor generator 21. This reduces vibration and noise in the air conditioning system 10. Note that, although the present embodiment shows a configuration in which the damper 237 is provided on the output shaft 201 of the engine 20, the present invention is not limited to this configuration. For example, the damper 237 may be provided on the rotating shaft 211 of the motor generator 21, as long as it is to absorb the difference in rotation speed between the engine 20 and the motor generator 21. In short, it is sufficient that the damper 237 is disposed between the engine 20 and the motor generator 21.

[0056] <Configuration of the cooling water circuit, configuration of the refrigerant circuit, and specific operation of the air conditioning system> Next, the configuration of the coolant circuit 15, the configuration of the refrigerant circuit 13, and the specific operation of the air conditioning system 10 will be described.

[0057] The coolant circuit 15 is a circuit configured to circulate coolant that cools the engine 20 and the motor generator 21. The coolant circuit 15 includes a coolant passage 31, a coolant pump 32, an exhaust heat exchanger 33, an ATF cooler 34, a waste heat recovery heat exchanger 35, and a radiator 36. The coolant passage 31 is a passage configured to allow coolant to flow. The coolant pump 32 is configured to circulate coolant through the coolant circuit 15 when it is operated. The exhaust heat exchanger 33 is configured to exchange heat between the exhaust gas of the engine 20 and the coolant. The ATF cooler 34 is configured to exchange heat between the coolant and lubricating oil that lubricates each part of the power transmission mechanism 23A. The waste heat recovery heat exchanger 35 is configured to exchange heat between a refrigerant and the coolant. The radiator 36 is configured to dissipate heat contained in the coolant to the outside air.

[0058] The coolant circuit 15 is configured so that, by operation of the coolant pump 32, the coolant circulates through the radiator 36, the exhaust heat exchanger 33, a water jacket (not shown) of the engine 20, the exhaust heat recovery heat exchanger 35, and the radiator 36 in that order. The coolant circuit 15 is also configured so that a portion of the coolant that has passed through the radiator 36 passes through the ATF cooler 34 before flowing into the exhaust heat exchanger 33.

[0059] A portion of the coolant (cooled coolant) that has dissipated heat in the radiator 36 flows into the ATF cooler 34, where it exchanges heat with the lubricating oil. This cools the lubricating oil. In this embodiment, the motor generator 21 is configured to be cooled by the lubricating oil. Therefore, the motor generator 21 is cooled by cooling the lubricating oil. The coolant cooled in the radiator 36 (including the coolant that has passed through the ATF cooler 34) passes sequentially through the exhaust heat exchanger 33 and the water jacket (not shown) of the engine 20. The coolant then absorbs heat from the exhaust gas of the engine 20 as it passes through the exhaust heat exchanger 33, and absorbs heat from the engine 20 as it passes through the water jacket of the engine 20.

[0060] The coolant then passes through the exhaust heat recovery heat exchanger 35, exchanging heat with the refrigerant and thereby providing heat to the refrigerant. The coolant that has passed through the exhaust heat recovery heat exchanger 35 flows into the radiator 36. The coolant is then cooled by exchanging heat with outside air as it passes through the radiator 36. In this way, the coolant circuit 15 is configured to remove heat from the exhaust gas of the engine 20, the engine 20, and the motor generator 21 using the coolant and provide the removed heat to the refrigerant.

[0061] The refrigerant circuit 13 is a circuit through which a refrigerant circulates. In addition to two compressors 22a and 22b, the refrigerant circuit 13 includes a refrigerant path 41, a four-way valve 42, an oil separator 43, an accumulator 44, an outdoor heat exchanger 45, an exhaust heat recovery heat exchanger 35, an indoor electronic expansion valve 46, and an indoor heat exchanger 47. The refrigerant path 41 includes a discharge path 51, an intermediate path 52, an accumulator inlet path 53, an accumulator outlet path 54, a bypass path 55, an oil discharge path 56, an outdoor unit side refrigerant path 57, and an indoor unit side refrigerant path 58.

[0062] The two compressors 22a, 22b each include a refrigerant suction port 222 and a refrigerant discharge port 223. When driven (operated), the two compressors 22a, 22b are configured to draw in refrigerant from the refrigerant suction port 222, compress the drawn refrigerant, and discharge the compressed refrigerant from the refrigerant discharge port 223. The refrigerant discharge port 223 of each of the two compressors 22a, 22b is connected to a first port 421 of a four-way valve 42, which will be described later, by a discharge path 51.

[0063] The four-way valve 42 has four ports: a first port 421, a second port 422, a third port 423, and a fourth port 424. The four-way valve 42 is configured to be able to selectively realize a first state and a second state. In the first state, the first port 421 and the second port 422 are in communication with each other, and the third port 423 and the fourth port 424 are in communication with each other. In the second state, the first port 421 and the third port 423 are in communication with each other, and the second port 422 and the fourth port 424 are in communication with each other. Under the control of the control device 16, the four-way valve 42 is set to the first state in the heating mode of the air conditioning system 10, and to the second state in the cooling mode.

[0064] The oil separator 43 has a refrigerant inlet 431, a refrigerant outlet 432, and an oil discharge port 433. The oil separator 43 is configured to separate the compressor oil from a mixture of refrigerant and compressor oil that flows in through the refrigerant inlet 431, and the refrigerant flows out through the refrigerant outlet 432 and the compressor oil is discharged through the oil discharge port 433. The oil separator 43 is disposed on a discharge path 51. The refrigerant inlet 431 is connected to the refrigerant discharge ports 223 of the two compressors 22a and 22b via the discharge path 51, and the refrigerant outlet 432 is connected to the first port 421 of the four-way valve 42 via the discharge path 51. The oil discharge port 433 of the oil separator 43 is connected to the refrigerant suction ports 222 of the two compressors 22a and 22b via an oil discharge path 56 and an accumulator outlet path 54.

[0065] The accumulator 44 has a first refrigerant inlet 441, a second refrigerant inlet 442, and a refrigerant outlet 443. The accumulator 44 is configured so that the refrigerant (gas-liquid two-phase refrigerant) flowing in through each of the first refrigerant inlet 441 and the second refrigerant inlet 442 is separated into gas phase refrigerant and liquid phase refrigerant, and the gas phase refrigerant flows out from the refrigerant outlet 443. The first refrigerant inlet 441 of the accumulator 44 is connected to the fourth port 424 of the four-way valve 42 via an accumulator inlet path 53. The second refrigerant inlet 442 is connected to one end of a bypass path 55. The refrigerant outlet 443 of the accumulator 44 is connected to the refrigerant suction ports 222 of the two compressors 22a, 22b via an accumulator outlet path 54.

[0066] The outdoor heat exchanger 45 is configured to exchange heat between the refrigerant flowing through an internal path and the outdoor air. The configuration of the outdoor heat exchanger 45 is not particularly limited, and a conventionally known configuration can be applied. One end of the internal path of the outdoor heat exchanger 45 is connected to the third port 423 of the four-way valve 42 via the outdoor unit side refrigerant path 57, and the other end is connected to the indoor heat exchangers 47 of each of the multiple indoor units 12 via the intermediate path 52.

[0067] As described above, the exhaust heat recovery heat exchanger 35 is included in the coolant circuit 15 and also in the refrigerant circuit 13. The exhaust heat recovery heat exchanger 35 is disposed on the bypass path 55. The exhaust heat recovery heat exchanger 35 is configured to exchange heat between the coolant flowing through the coolant path 31 and the refrigerant flowing through the bypass path 55 (to transfer heat of the coolant to the refrigerant). One end of the bypass path 55 is connected to the second refrigerant inlet 442 of the accumulator 44, and the other end is connected to the intermediate path 52.

[0068] The indoor heat exchanger 47 is configured to allow refrigerant to pass through it and to exchange heat between the passing refrigerant and the indoor air. One end of the indoor heat exchanger 47 is connected to the second port 422 of the four-way valve 42 via an indoor unit side refrigerant path 58. The other end of the indoor heat exchanger 47 is connected to the other end of the outdoor heat exchanger 45 via an intermediate path 52. The indoor side electronic expansion valve 46 is arranged on the intermediate path 52.

[0069] Next, the air conditioning operation of the air conditioning system 10 will be described. The air conditioning system 10 has a heating mode and a cooling mode as air conditioning modes. The four-way valve 42 is set to a first state in the heating mode and to a second state in the cooling mode. In FIG. 1, the flow of refrigerant during heating operation (operation in the heating mode) is indicated by solid arrows, and the flow of refrigerant during cooling operation (operation in the cooling mode) is indicated by dashed lines.

[0070] Heating operation is as follows. The two compressors 22a, 22b are driven by the driving force of at least one of the engine 20 and the motor generator 21, so that they draw in low-temperature, low-pressure gas-phase refrigerant from the accumulator outlet path 54 through the refrigerant suction port 222, compress it, and discharge the high-temperature, high-pressure gas-phase refrigerant from the refrigerant discharge port 223. The refrigerant discharged from the refrigerant discharge port 223 passes through the discharge path 51 and flows into the first port 421 of the four-way valve 42. An oil separator 43 is disposed on the discharge path 51, and the refrigerant (refrigerant mixed with compressor oil) discharged from the two compressors 22a, 22b is separated into the refrigerant and the compressor oil while passing through the oil separator 43. The compressor oil separated from the refrigerant is discharged from the oil separator 43 through the oil discharge port 433 and flows into the refrigerant suction ports 222 of the two compressors 22a, 22b via the oil discharge path 56 and the accumulator outlet path 54.

[0071] When the air conditioning mode is the heating mode, the four-way valve 42 is set to the first state (a state in which the first port 421 is connected to the second port 422). Therefore, the refrigerant (high-temperature, high-pressure refrigerant) that flows from the discharge path 51 into the first port 421 of the four-way valve 42 flows out of the four-way valve 42 through the second port 422, passes through the indoor unit-side refrigerant path 58 connected to the second port 422, and flows into the indoor heat exchangers 47 of each indoor unit 12. The refrigerant that flows into the indoor heat exchanger 47 releases heat into the room in the indoor heat exchanger 47 (exchanges heat with the indoor air), and a portion of the refrigerant condenses.

[0072] The refrigerant that has passed through the indoor heat exchanger 47 flows into the intermediate path 52 and is pressurized to an intermediate pressure when it passes through the indoor electronic expansion valve 46 arranged on the intermediate path 52. The intermediate-pressure refrigerant flows into the outdoor heat exchanger 45, and a portion of the refrigerant flows into the bypass path 55. The refrigerant that has flowed into the outdoor heat exchanger 45 exchanges heat with the outdoor air (removes heat from the outdoor air) and is partially vaporized. The partially vaporized refrigerant passes through the outdoor unit side refrigerant path 57 and flows into the third port 423 of the four-way valve 42. The refrigerant that has flowed into the exhaust heat recovery heat exchanger 35 exchanges heat with the coolant flowing in the coolant circuit 15 (removes heat from the coolant).

[0073] When the air conditioning mode is the heating mode, the third port 423 of the four-way valve 42 is in communication with the fourth port 424. Therefore, the refrigerant that flows from the outdoor unit side refrigerant path 57 into the third port 423 of the four-way valve 42 passes through the fourth port 424 and the accumulator inlet path 53, and flows into the first refrigerant inlet 441 of the accumulator 44. In this way, low-temperature, low-pressure refrigerant that has returned from the indoor unit 12 flows through the accumulator inlet path 53. In addition, the refrigerant that flows into the bypass path 55 from the intermediate path 52 is heat exchanged with coolant in the exhaust heat recovery heat exchanger 35 that is arranged on the bypass path 55, and then flows into the second refrigerant inlet 442 of the accumulator 44.

[0074] The refrigerant that flows into the accumulator 44 is separated into gas phase refrigerant and liquid phase refrigerant, and the low temperature, low pressure gas phase refrigerant passes through the accumulator outlet path 54 and flows into the refrigerant suction ports 222 of the compressors 22a and 22b. This refrigerant circulation cycle is repeated, thereby continuing the room heating.

[0075] Cooling operation is as follows. As in heating operation, high-temperature, high-pressure gas-phase refrigerant is discharged from the refrigerant discharge ports 223 of the two compressors 22a, 22b. The discharged refrigerant is separated from the compressor oil in the oil separator 43 and flows into the first port 421 of the four-way valve 42. When the air conditioning mode is cooling mode, the four-way valve 42 is set to the second state (a state in which the first port 421 and the third port 423 of the four-way valve 42 are connected). Therefore, the refrigerant that flows from the discharge path 51 into the first port 421 of the four-way valve 42 passes through the third port 423 and the outdoor-unit-side refrigerant path 57 and flows into the outdoor heat exchanger 45. Then, the refrigerant (high-temperature, high-pressure gas-phase refrigerant) that flows into the outdoor heat exchanger 45 releases heat to the outside air (exchanges heat with the outside air) while passing through the outdoor heat exchanger 45, causing a portion of it to condense.

[0076] The refrigerant that has passed through the outdoor heat exchanger 45 flows into the indoor heat exchanger 47 of each indoor unit 12 through the intermediate path 52. During cooling operation, the flow control valve 48 located on the bypass path 55 is generally closed to prevent the refrigerant from flowing through the exhaust heat recovery heat exchanger 35. An indoor electronic expansion valve 46 configured to expand (lower the pressure of) the refrigerant passing through is located on the indoor unit 12 side of the intermediate path 52. Therefore, expanded (lower-pressurized) refrigerant flows into the indoor heat exchanger 47 to facilitate evaporation. The refrigerant that has flowed into the indoor heat exchanger 47 absorbs heat from the indoor air as it passes through the indoor heat exchanger 47 and evaporates (exchanges heat with the indoor air). This cools the indoor air, cooling the room. The refrigerant that has passed through the indoor heat exchanger 47 flows into the second port 422 of the four-way valve 42 through the indoor unit-side refrigerant path 58.

[0077] When the air conditioning mode is the cooling mode, the four-way valve 42 is maintained in the second state (a state in which the second port 422 is connected to the fourth port 424). Therefore, the refrigerant that flows into the second port 422 of the four-way valve 42 flows into the first refrigerant inlet 441 of the accumulator 44 through the accumulator inlet path 53. In this way, as in the cooling operation, low-temperature, low-pressure refrigerant returning from the indoor unit 12 flows through the accumulator inlet path 53. Then, as in the heating operation, the refrigerant is separated into gas and liquid in the accumulator 44, and the low-temperature, low-pressure gas-phase refrigerant flows into the refrigerant suction ports 222 of the two compressors 22a, 22b through the accumulator outlet path 54. This refrigerant circulation cycle is repeated, thereby continuing indoor cooling.

[0078] The above-described configuration and operation of the refrigerant circuit 13 are merely an example, and the configuration and operation of the refrigerant circuit 13 are not limited to the above-described configuration and operation.

[0079] <Modifications of the power unit and power transmission mechanism> Next, power units 14B to 14F according to first to fifth modified examples and power transmission mechanisms 23B to 23F according to first to fifth modified examples will be described. Each power unit 14B to 14B according to each modified example includes one engine 20, one motor generator 21, two compressors (a first compressor 22a and a second compressor 22b), and the power transmission mechanism 23B to 23F according to the modified example. The same configurations as those in the above-described embodiment can be applied to the engine 20, the motor generator 21, and the two compressors 22a and 22b. Furthermore, the configurations of the air conditioning system 10 to which the power units 14B to 14F according to the modified examples are applied, other than the power units 14B to 14F, are the same as those in the above-described embodiment. Note that a description of the configurations common to the above-described embodiment will be omitted.

[0080] <First Modification> FIG. 4 is a diagram showing the configuration of a power unit 14B according to a first modified example. The power unit 14B according to the first modified example is applied to a power transmission mechanism 23B according to the first modified example. As shown in FIG. 4, in the power unit 14B according to the first modified example, the engine 20 and the two compressors 22a and 22b are arranged on the same side of the gear train of the power transmission mechanism 23B (more specifically, on one side parallel to the rotational axes of the gears), and the motor generator 21 is arranged on the side opposite to the side on which the engine 20 and the two compressors 22a and 22b are arranged. In other words, the engine 20 and the two compressors 22a and 22b and the motor generator 21 are arranged on opposite sides of the power transmission mechanism 23A in the direction parallel to the rotational axes of the gears. In other words, the engine 20 and the two compressors 22a and 22b and the motor generator 21 are arranged so as to face each other across the power transmission mechanism 23A.

[0081] The power transmission mechanism 23B has the same configuration as the power transmission mechanism 23A according to the above embodiment, except for the direction in which the input shafts 221a, 221b of the two compressors 22a, 22b protrude from the housing 238. That is, in the power transmission mechanism 23A according to the above embodiment, the input shafts 221a, 221b of the two compressors 22a, 22b protrude in the opposite direction to the output shaft 201 of the engine 20, whereas in the power transmission mechanism 23B according to the first modified example, the input shafts 221a, 221b of the two compressors 22a, 22b protrude in the same direction as the output shaft 201 of the engine 20 (the opposite direction to the rotation shaft 211 of the motor generator 21).

[0082] Note that, because the arrangement direction of the two compressors 22a and 22b is opposite to that of the above embodiment, the rotation direction of the input shafts 221a and 221b of the two compressors 22a and 22b is opposite to that of the above embodiment. Therefore, in order to adjust the rotation direction of the input shafts 221a and 221b of the two compressors 22a and 22b, the power transmission mechanism 23B may be provided with two CT gears 234. In this case, a configuration in which the two CT gears 234 directly mesh with each other, one CT gear 234 directly meshes with the EG shaft gear 231, and the other CT gear 234 directly meshes with each of the two CP shaft gears 233a and 233b can be applied.

[0083] <Second modified example> FIG. 5 is a diagram showing the configuration of a power unit 14C according to a second modified example. A power transmission mechanism 23C according to the second modified example is applied to the power unit 14C according to the second modified example. As shown in FIG. 5, in the power unit 14C according to the second modified example, the engine 20 and the motor generator 21 are disposed on the same side of the gear train of the power transmission mechanism 23C (more specifically, on one side parallel to the rotational axes of the gears), and the two compressors 22a, 22b are disposed on the side opposite to the side on which the engine 20 and the motor generator 21 are disposed. In other words, the engine 20 and the motor generator 21 and the two compressors 22a, 22b are disposed on opposite sides of the power transmission mechanism 23C in the direction parallel to the rotational axes of the gears. In other words, the engine 20 and the motor generator 21 and the two compressors 22a, 22b are disposed so as to face each other across the power transmission mechanism 23C.

[0084] The power transmission mechanism 23C has the same configuration as the power transmission mechanism 23A according to the above embodiment, except for the direction in which the rotating shaft 211 of the motor generator 21 protrudes from the housing 238. That is, in the power transmission mechanism 23A according to the above embodiment, the rotating shaft 211 of the motor generator 21 protrudes in the opposite direction to the output shaft 201 of the engine 20, whereas in the power transmission mechanism 23C according to the second modified example, the rotating shaft 211 of the motor generator 21 protrudes in the same direction as the output shaft 201 of the engine 20.

[0085] <Third Modification> Fig. 6 is a diagram showing the configuration of a power unit 14D according to a third modified example. A power transmission mechanism 23D according to a third modified example is applied to the power unit 14D according to the third modified example. As shown in Fig. 6, in the power unit 14D according to the third modified example, the engine 20, the motor generator 21, and the two compressors 22a, 22b are arranged on the same side of the gear train of the power transmission mechanism 23D (more specifically, on the same side in a direction parallel to the rotation axis of each gear).

[0086] The power transmission mechanism 23D has the same configuration as the power transmission mechanism 23A according to the above embodiment, except for the direction in which the rotating shaft 211 of the motor generator 21 and the input shafts 221a, 221b of the two compressors 22a, 22b protrude from the housing. That is, in the power transmission mechanism 23A according to the above embodiment, the rotating shaft 211 of the motor generator 21 and the input shafts 221a, 221b of the two compressors 22a, 22b protrude in the direction opposite to the output shaft 201 of the engine 20, whereas in the power transmission mechanism 23D according to the third modification, the rotating shaft 211 of the motor generator 21 and the input shafts 221a, 221b of the two compressors 22a, 22b protrude on the same side. Note that, as in the first modification, the arrangement direction of the two compressors 22a, 22b is opposite to that of the above embodiment, and therefore the power transmission mechanism 23D may include two CT gears 234.

[0087] <Fourth Modification> FIG. 7 is a diagram showing the configuration of a power unit 14E according to a fourth modified example. The power unit 14E according to the fourth modified example is applied to a power transmission mechanism 23E according to the fourth modified example. As shown in FIG. 7, in the power unit 14E according to the fourth modified example, the engine 20 and the two compressors 22a and 22b are disposed on the same side of the gear train of the power transmission mechanism 23B (more specifically, on one side parallel to the rotational axes of the gears), and the motor generator 21 is disposed on the side opposite to the side on which the engine 20 and the two compressors 22a and 22b are disposed. In other words, the engine 20 and the two compressors 22a and 22b and the motor generator 21 are disposed on opposite sides of the power transmission mechanism 23E in the direction parallel to the rotational axes of the gears. In other words, the engine 20 and the two compressors 22a and 22b and the motor generator 21 are disposed so as to face each other across the power transmission mechanism 23E.

[0088] The power transmission mechanism 23E includes one EG shaft gear 231, one MG shaft gear 232, two CP shaft gears 233a and 233b (i.e., the same number as the compressors 22a and 22b), one CT gear 234, one EG shaft clutch 235, two CP shaft clutches 236a and 236b (i.e., the same number as the compressors 22a and 22b), a damper 237, and a housing 238. The EG shaft gear 231 is located on one side (the upper side is shown in an example in FIG. 7) of the MG shaft gear 232, and the MG shaft gear 232 and the EG shaft gear 231 are directly meshed with each other. The CT gear 234 is located on one side (the lower side is shown in an example in FIG. 7) opposite to the one side of the MG shaft gear 232, and the MG shaft gear 232 and the CT gear 234 are directly meshed with each other. That is, the power transmission mechanism 23E according to the fourth modification has a configuration in which the EG shaft gear 231 and the MG shaft gear 232 are interchanged when compared with the power transmission mechanism 23A according to the above embodiment.

[0089] <Fifth Modification> FIG. 8 is a diagram showing the configuration of a power unit 14F according to a fifth modified example. A power transmission mechanism 23F according to a fifth modified example is applied to the power unit 14F according to the fifth modified example. As shown in FIG. 8, in the power unit 14F according to the fifth modified example, the motor generator 21 is disposed on one side of the engine 20 in a direction parallel to the output shaft 201 of the engine 20, and the two compressors 22a, 22b are disposed on the other side of the engine 20 (the side opposite to the side on which the motor generator 21 is disposed). In other words, the motor generator 21 and the two compressors 22a, 22b are disposed on opposite sides of the engine 20.

[0090] The power transmission mechanism 23F according to the fifth modification includes an MG side power transmission mechanism 61 and a CP side power transmission mechanism 62. The MG side power transmission mechanism 61 includes an MG side EG shaft gear 611, an MG shaft gear 232, and an MG side housing 612. The MG side EG shaft gear 611 is a gear that is coaxially provided on one end of the output shaft 201 of the engine 20 via a damper 237. The MG side housing 612 is a container (casing) that rotatably accommodates the MG side EG shaft gear 611 and the MG shaft gear 232. The MG side EG shaft gear 611 and the MG shaft gear 232 are directly meshed with each other. Therefore, the MG side power transmission mechanism 61 is configured to transmit the driving force output by the engine 20 to the motor generator 21.

[0091] The CP-side power transmission mechanism 62 includes a CP-side EG shaft gear 621, two CP shaft gears 233a and 233b, and a CP-side housing 622. The CP-side EG shaft gear 621 is a gear that is coaxially provided on the end of the output shaft 201 of the engine 20 opposite to the end on which the MG-side EG shaft gear 611 is provided. The CP-side housing 622 is a container (casing) that rotatably accommodates the CP-side EG shaft gear 621 and the two CP shaft gears 233a and 233b. The CP-side EG shaft gear 621 is directly meshed with each of the two CP shaft gears 233a and 233b. Therefore, the CP-side power transmission mechanism 62 is configured to transmit the driving force output by the engine 20 to the two compressors 22a and 22b.

[0092] <Summary of the embodiment> (1) The hybrid air conditioning system 10 according to this embodiment is a refrigerant circuit 13 including an indoor heat exchanger 47 and an outdoor heat exchanger 45; a motor (motor generator 21) that generates driving force when supplied with electric power; a motor gear (MG shaft gear 232) that is coaxially attached to a motor shaft (rotating shaft 211) that is an output shaft of the motor (motor generator 21); an engine 20 that generates driving force when fuel is supplied; an engine gear (EG shaft gear 231) that is coaxially attached to an engine shaft (output shaft 201) that is an output shaft of the engine 20; compressors (first compressor 22a, second compressor 22b) that operate when a driving force output from at least one of the motor (motor generator 21) and the engine 20 is transmitted to input shafts 221a, 221b, and that circulate a refrigerant through the refrigerant circuit 13; compressor gears (CP shaft gears 233a, 233b) that are coaxially attached to the input shafts 221a, 221b of the compressors (first compressor 22a, second compressor 22b) and that are linked to the engine gear (EG shaft gear 231) so as to be able to transmit driving force; Equipped with the engine gear (EG shaft gear 231), the motor gear (MG shaft gear 232), and the input shafts 221a and 221b of the compressors (first compressor 22a and second compressor 22b) are linked to each other so as to be able to transmit power; The motor gear (MG shaft gear 232), the engine gear (EG shaft gear 231), and the compressor gears (CP shaft gears 233a, 233b) are arranged on the same plane.

[0093] According to this configuration, it is possible to reduce the size of the power units 14A, 14B, 14C, 14D, and 14E each including the engine 20, the motor (motor generator 21), and the compressors 22a and 22b (in other words, to reduce the space required for the power units 14A, 14B, 14C, 14D, and 14E). That is, the driving force of the engine 20 and the driving force of the motor (motor generator 21) are connected to each other so as to be transmitted to the input shafts 221a and 221b of the compressors (first compressor 22a and second compressor 22b) via the motor gear (MG shaft gear 232) and the engine gear (EG shaft gear 231), respectively. Therefore, the compressors (first compressor 22a and second compressor 22b) can be driven (operated) by one or both of the driving force of the engine 20 and the driving force of the motor (motor generator 21). That is, a hybrid air conditioning system 10 is constructed that operates by the driving force of the motor (motor generator 21) and the engine 20.

[0094] Furthermore, with this configuration, the dimension of the power transmission mechanism 23A, which includes the motor gear (MG shaft gear 232), the engine gear (EG shaft gear 231), and the compressor gears (CP shaft gears 233a, 233b), in a direction parallel to the output shaft 201 of the engine 20 can be reduced. Therefore, the distance between the engine 20 and the motor (motor generator 21) and the distance between the engine 20 and the compressors (first compressor 22a, second compressor 22b) can be reduced, and therefore the dimension of the hybrid air conditioning system 10 in a direction parallel to the output shaft 201 of the engine 20 can be reduced.

[0095] Furthermore, if the engine gear (EG shaft gear 231) and the motor gear (MG shaft gear 232) are configured to be linked so as to be able to transmit power, a decrease in the efficiency of power transmission between the engine 20 and the motor (motor generator 21) is prevented or suppressed. For example, if the output shaft 201 of the engine 20 and the output shaft (rotating shaft 211) of the motor (motor generator 21) are configured to be linked so as to be able to transmit power by a combination of a pulley and a belt, the efficiency of power transmission decreases due to slippage of the belt. In contrast, according to this embodiment, gears are used to transmit power, so it is possible to increase the efficiency of power transmission (prevent or suppress a decrease in the efficiency of power transmission).

[0096] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Various modifications of the present invention are possible without departing from the spirit of the present invention, and such modifications are also included in the scope of the present invention.

[0097] For example, in the present embodiment, the air conditioning system 10 includes the motor-generator 21 that functions as both a power source and a generator. However, the present invention is not limited to such a configuration. For example, the air conditioning system 10 may include a motor and a generator separately. In this case, for example, when viewed in a direction parallel to the output shaft 201 of the engine 20, the rotational shaft of the motor and the rotational shaft of the generator may be arranged in line-symmetric positions with respect to a single imaginary line (e.g., a vertical line) that passes through the output shaft 201 of the engine 20, and the input shafts 221a and 221b of the two compressors 22a and 22b may be arranged in line-symmetric positions with respect to the single line. In this case, the rotational shaft of the motor and the rotational shaft of the generator may be arranged inside the outline of the engine 20 when viewed in a direction parallel to the output shaft 201 of the engine 20. Even with such a configuration, the same effects as those described above can be achieved.

[0098] In addition, in the above embodiment, an example was shown in which the engine 20 is a gas engine that operates by receiving a supply of gas, but the engine 20 applied to the air conditioning system 10 is not limited to a gas engine. For example, the engine 20 may be an engine that operates by receiving a supply of liquid fuel.

[0099] Furthermore, in the above embodiment, the air conditioning system 10 is configured to include two compressors 22a and 22b, but is not limited to such a configuration. For example, the air conditioning system 10 may be configured to include one compressor 22a and 22b. In this case, a configuration may be applied in which, when viewed in a direction parallel to the output shaft 201 of the engine 20, the output shaft 201 of the engine 20, the rotating shaft 211 of the motor-generator 21, and the input shafts 221a and 221b of the one compressor 22a and 22b are arranged on a single imaginary straight line (e.g., a vertical line). Even with such a configuration, the same effects as those described above can be achieved. [Explanation of symbols]

[0100] 10... Hybrid air conditioning system, 12... Refrigerant circuit, 14A, 14B, 14C, 14D, 14E, 14F... Power unit, 20... Engine, 21... Motor generator, 211... Rotating shaft of motor generator, 22a... First compressor, 22b... Second compressor, 23A, 23B, 23C, 23D, 23E, 23F... Power transmission mechanism, 201... Engine output shaft, 231... EG shaft gear, 232... MG shaft gear, 233a, 233b... CP shaft gear, 234... CT gear, 235... EG shaft clutch, 236a, 236b... CP shaft clutch, 237... Damper

Claims

[Claim 1] a refrigerant circuit including an indoor heat exchanger and an outdoor heat exchanger; a motor that generates driving force when supplied with power; a motor gear attached coaxially to a motor shaft that is an output shaft of the motor; an engine that generates driving force when fuel is supplied; an engine gear attached coaxially to an engine shaft which is an output shaft of the engine; a compressor that operates when a driving force output from at least one of the motor and the engine is transmitted to an input shaft, and that circulates a refrigerant through the refrigerant circuit; a compressor gear that is coaxially attached to the input shaft of the compressor and that is linked to the engine gear so as to be able to transmit driving force; Equipped with the engine gear, the motor gear, and the input shaft of the compressor are linked together so as to be able to transmit power; A hybrid air conditioning system, wherein the motor gear, the engine gear, and the compressor gear are arranged on the same plane.

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