JP2010018060A - Vehicular refrigeration circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a coefficient of performance as high as possible in a vehicular refrigeration circuit in which a swash plate type compressor is adopted. <P>SOLUTION: The vehicular refrigeration circuit adopts the swash plate type compressor 1. The swash plate type compressor 1 is composed such that each cylinder bore 13a and a suction room 1a can communicate by a suction port 17a. The vehicular refrigeration circuit is adjacent to the specific suction port 17s being at least one of the suction port 17a, and includes: a capillary tube 57 for outputting based on a temperature or pressure of a refrigerant near the specific suction port 17s; and an adjusting valve 10 for adjusting the flow volume of the refrigerant supplying to an evaporator 11 based on the output of the capillary tube 57. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle refrigeration circuit that includes a specific type of compressor and is used in a vehicle air conditioner.

  A general refrigeration circuit includes a compressor having a suction chamber and a discharge chamber, a condenser connected to the discharge chamber, an expansion valve connected to the condenser, an expansion valve, and a suction chamber. The evaporator and the refrigerant | coolant which circulates between a compressor, a condenser, an expansion valve, and an evaporator are provided.

  In general refrigeration circuits, various types of compressors are employed. As expansion valves, an external pressure equalizing expansion valve and an internal pressure equalizing expansion valve are known. The external pressure equalization type expansion valve is connected to a temperature sensing cylinder that detects the pressure of the refrigerant on the outlet side of the evaporator, and the temperature sensing cylinder. The valve body is displaced by the displacement of the diaphragm in the diaphragm chamber, and the refrigerant flows. And an adjustment valve for changing the opening of the flow path. The internal pressure equalization type expansion valve has a temperature sensing rod for detecting the pressure of the refrigerant on the outlet side of the evaporator, and the temperature sensing rod is built in the housing so as to change the opening of the flow path through which the refrigerant flows. It is configured. There is also known an expansion valve including a pressure sensor that outputs an output signal based on the pressure of the refrigerant on the outlet side of the evaporator, and an injection that changes the injection amount of the refrigerant based on the output signal.

  In this refrigeration circuit, the refrigerant in the suction chamber of the compressor has an evaporation pressure as indicated by a point A in FIG. 10, and a temperature obtained by adding a superheat degree to the evaporation temperature. The refrigerant in the suction chamber includes an enthalpy Δhs corresponding to the degree of superheat because the temperature includes the degree of superheat. As shown from point A to point B in the figure, the compressor compresses the refrigerant in the suction chamber and discharges it to the discharge chamber under the condition that the entropy does not change ideally. As for the refrigerant in the discharge chamber, the pressure is the condensation pressure and the temperature is the discharge temperature, as indicated by point B in the figure.

  The refrigerant supplied to the condenser is cooled to the condensing temperature at the condensing pressure and reaches the saturated vapor temperature, and then becomes a supercooled saturated liquid, as shown from B point to C point in the figure. .

  The refrigerant supplied to the expansion valve is depressurized under adiabatic conditions from the condensation pressure to the evaporation pressure, as shown from point C to point D in the figure. At this time, the expansion valve controls the flow rate of the refrigerant so that the degree of superheat becomes constant based on the temperature or pressure of the refrigerant on the outlet side of the evaporator. More specifically, if the temperature or pressure on the outlet side of the evaporator is higher than a set value, the expansion valve increases the opening to increase the amount of refrigerant supplied to the evaporator. If the temperature or pressure on the outlet side of the evaporator is lower than the set value, the expansion valve reduces the opening to reduce the amount of refrigerant supplied to the evaporator. That is, the expansion valve rapidly expands by injecting a high-temperature / high-pressure liquid refrigerant from a small hole to form a low-temperature / low-pressure mist refrigerant, and the vaporization state of the refrigerant in the evaporator It works to adjust the amount of refrigerant. The expansion valve keeps the liquid refrigerant deprived of the surrounding heat and always keeps the evaporation at the outlet of the evaporator, so that the capacity of the evaporator can be fully exploited, depending on the cooling load fluctuation It is intended to automatically adjust the amount of refrigerant.

  And the refrigerant | coolant supplied to the evaporator becomes superheated steam, after obtaining heat from air and evaporating to saturated steam, as shown from D point to A point of the figure. Air conditioning is thus performed.

  However, the above operating conditions are ideal, and in actual refrigeration circuits, entropy increases due to heat loss, heat is generated by the heat generated by the compressor itself, and pressure loss due to refrigerant flow path resistance also occurs. Or increase in enthalpy, which is unlikely to be an ideal driving condition. For this reason, in a general refrigeration circuit, a decrease in coefficient of performance (COP) is inevitable.

  In this regard, in the vehicle refrigeration circuit disclosed in Patent Document 1, the opening degree of the expansion valve is corrected based on the temperature of the refrigerant discharged from the compressor so that the amount of refrigerant supplied to the evaporator is reduced. . In this case, the enthalpy Δhs corresponding to the degree of superheat imparted to the refrigerant in the suction chamber of the compressor is reduced. For this reason, it is considered that this refrigeration circuit approaches an ideal operating state and the coefficient of performance is improved. Further, in this refrigeration circuit, liquid compression is less likely to occur in the compressor, and effects such as improved durability can be obtained.

JP-A 63-263355

  However, according to the inventor's knowledge, the coefficient of performance is particularly low when the refrigeration circuit is for a vehicle and the refrigeration circuit employs a swash plate compressor.

  That is, when the refrigeration circuit is for a vehicle, the refrigeration circuit is irregularly heated in the engine room, and is susceptible to a difference in temperature depending on the environmental temperature. The degree of cooling varies greatly depending on the traveling speed of the vehicle.

  On the other hand, in the swash plate compressor, the suction chamber and the discharge chamber are formed adjacent to each other in the housing, and the refrigerant in the suction chamber is easily heated by the refrigerant in the discharge chamber. Further, in the swash plate compressor, friction heat is likely to be generated in the piston, and in the mechanism that converts the swinging motion of the swash plate into the reciprocating motion of the piston, the friction heat is also easily generated. It is easy to heat the refrigerant in the suction chamber.

  According to the inventor's actual measurement, in the swash plate type compressor, the power required for compressing the gaseous refrigerant is about 80% of the consumed power, and about 20% of the consumed power is heated by mechanical loss such as friction loss. Instead, the compressor is heated. The temperature of the refrigerant in the swash plate compressor rises from 3.6 to 4.6 ° C. from the upstream portion to the downstream portion of the suction chamber, and reaches a maximum of 22 from the downstream portion of the suction chamber to the suction port leading to each cylinder bore. ° C temperature will rise.

  The volumetric efficiency of a swash plate compressor is at most 70%, but heating the refrigerant sucked into each cylinder bore increases the volumetric efficiency at the same level as the dead volume re-expansion formed at the top dead center of the piston head. This is the main cause of the decrease. If the heated refrigerant is compressed, even if heat insulation is assumed in the compression process (isentropy), the power consumption required to obtain the same high pressure is increased compared to the case of compressing a low-temperature refrigerant. is there. Further, since the density of the high-temperature refrigerant is low, the mass discharged from the swash plate compressor is low, and the circulation rate is reduced, so that the cooling capacity is also lowered. In this way, if the heated refrigerant is sucked into each cylinder bore, the coefficient of performance decreases due to a synergistic effect that power consumption is large and cooling capacity is reduced.

  In this way, a high coefficient of performance can be achieved simply by making the degree of superheating constant based on the temperature and pressure of the refrigerant on the outlet side of the evaporator, or by correcting it based on the temperature of the refrigerant discharged from the compressor. It cannot be realized.

  The present invention has been made in view of the above-described conventional situation, and in a vehicle refrigeration circuit adopting a swash plate compressor, as a problem to be solved, it is possible to achieve as high a coefficient of performance as possible. Yes.

The vehicle refrigeration circuit of the present invention includes a first housing that forms a plurality of cylinder bores and a crank chamber, and is joined to the first housing and communicates with the cylinder bores to form a suction chamber and a discharge chamber that are adjacent to each other. A second housing, a drive shaft rotatably supported by the first housing and the second housing, a swash plate supported by the drive shaft in the crank chamber, and a reciprocating storage in each cylinder bore And a motion conversion mechanism that is provided between the swash plate and each piston, and that converts a swinging motion of the swash plate into a reciprocating motion of each piston. A swash plate compressor configured to communicate with the chamber by a suction port;
A condenser connected to the discharge chamber;
An evaporator connected to the condenser and connected to the suction chamber;
A vehicular refrigeration circuit comprising the swash plate compressor, a refrigerant circulating between the condenser and the evaporator,
Detection means for making an output based on the temperature or pressure of the refrigerant in the vicinity of the specific suction port, which is at least one of the suction ports, in the vicinity of the specific suction port;
And a flow rate adjusting means for adjusting the flow rate of the refrigerant supplied to the evaporator based on the output of the detection means.

  In the vehicle refrigeration circuit of the present invention, the detecting means detects the temperature or pressure of the refrigerant in the vicinity of the specific suction port, and the flow rate adjusting means adjusts the flow rate of the refrigerant supplied to the evaporator based on the output. For this reason, even if the refrigerant rises from the upstream portion to the downstream portion of the suction chamber and rises from the downstream portion of the suction chamber to each suction port by adopting the swash plate compressor, the specific suction port In a specific cylinder bore communicating with the refrigerant, a refrigerant having a temperature of approximately the evaporation temperature is sucked. It is also possible to suck a refrigerant having a temperature lower than the evaporation temperature into a specific cylinder bore.

  If a refrigerant having a substantially evaporating temperature is sucked into a specific cylinder bore, the degree of superheat of the refrigerant becomes smaller than that in the conventional case, or the degree of superheat becomes 0 degrees. That is, for the refrigerant in a specific cylinder bore, the enthalpy Δhs corresponding to the degree of superheat is made small or zero.

  If a refrigerant having a temperature lower than the evaporation temperature is sucked into a specific cylinder bore, the degree of superheat of the refrigerant becomes negative. That is, for the refrigerant in the specific cylinder bore, the enthalpy Δhs for the degree of superheat is negative.

  Further, in this refrigeration circuit for a vehicle, the temperature of the refrigerant from the upstream portion of the suction chamber to each suction port due to a difference in the degree of heating in the engine room, a difference in the environment around the vehicle, and a difference in the traveling speed of the vehicle. Even if the rise is irregular, the detection means accurately detects the temperature or pressure of the refrigerant in the vicinity of the specific suction port, so that the refrigerant sucked into the specific cylinder bore also accurately reflects the difference or difference. It will be a thing.

  Therefore, according to the vehicle refrigeration circuit of the present invention, the volumetric efficiency of the swash plate compressor can be improved and the power consumption can be reduced regardless of the unstable factors caused by being used in the vehicle air conditioner. Moreover, since the circulation amount of the refrigerant increases, a high coefficient of performance can be realized.

  Further, in the vehicle refrigeration circuit of the present invention, liquid compression is unlikely to occur in the swash plate compressor, and effects such as improved durability can be obtained.

  In order to improve the performance of the evaporator, improvement of the heat transfer coefficient in the flow path is one means. If the refrigerant has a dryness of 0.7 to 0.9, an annular flow develops in the flow path, and the heat transfer coefficient becomes very large. When the dryness of the refrigerant is 0.9 or more, the refrigerant becomes a spray flow in the flow path, and the heat transfer coefficient is drastically reduced. For this reason, the degree of superheat of the refrigerant sucked into a specific cylinder bore improves heat transfer performance closer to 0 than when it is positive.

  In the present invention, the specific suction port may be one or plural. One specific suction port is preferably a suction port at a position where the refrigerant hardly flows from the upstream portion of the suction chamber. This is because the intake port supplies the cylinder bore with the refrigerant having the highest temperature rise. In addition, if the number of specific suction ports is the same as the number of cylinders of the swash plate compressor, it becomes possible to supply refrigerant at a preferable temperature into all the cylinder bores of the swash plate compressor, thereby realizing the highest coefficient of performance. be able to.

  The flow rate adjusting means may be provided between the condenser and the evaporator. In this case, since the evaporator exists downstream of the flow rate adjusting means, it is easy to adjust the flow rate of the refrigerant supplied to the evaporator. It should be noted that the flow rate adjusting means is provided at the same position as the conventional expansion valve, and it is possible to suppress an increase in the cost of the vehicle air conditioner without causing a significant change in the configuration of the vehicle refrigeration circuit.

  A bypass passage communicating with the suction chamber may be provided between the condenser and the expansion valve. The flow rate adjusting means can be provided in the bypass passage.

  In this case, the refrigerant composed of the saturated liquid supercooled through the condenser with the flow rate adjusted by the flow rate adjusting means is supplied to the suction chamber through the bypass passage. The refrigerant of the saturated liquid is depressurized from the condensation pressure in the suction chamber and absorbs heat in the suction chamber. For this reason, it becomes possible to suppress the temperature rise of the refrigerant from the upstream portion of the suction chamber to each suction port, and the coefficient of performance is further improved.

  In this case, since the swash plate compressor can be cooled by a small amount of saturated refrigerant, the lubrication is improved by increasing the oil viscosity in the swash plate compressor, the temperature of the lip seal is reduced, and between the piston and cylinder bore or between the shoe and piston. This reduces the thermal deformation of the material and improves the reliability.

  The detection means may detect the saturation pressure of the refrigerant corresponding to the temperature of the refrigerant in the vicinity of the specific suction port. The refrigerant in the vicinity of the suction port is caused to flow by the reciprocating motion of the piston, and it is difficult to accurately detect the temperature with a thermocouple or the like. It is easier to detect the saturation pressure of the refrigerant corresponding to the temperature.

  More specifically, the detection means may be a temperature sensitive cylinder in which a refrigerant is hermetically sealed in a gas-liquid mixed state. The flow rate adjusting means may be an adjustment valve that changes the opening degree of the flow path through which the refrigerant flows by opposing the pressure in the temperature sensitive cylinder and the pressure on the outlet side of the evaporator. In this case, a conventional adjustment valve for an external pressure equalization type expansion valve can be used as the flow rate adjusting means of the present invention.

  Further, the detection means may be composed of a temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a pressure sensor that outputs an output signal based on the pressure in the temperature sensing cylinder. The flow rate adjusting means may be an injection that changes the injection amount of the refrigerant based on the output signal. In this case, the present invention is embodied by the temperature sensitive cylinder, the pressure sensor, and the injection.

  Second detection means for performing a second output based on the temperature or pressure of the refrigerant on the outlet side of the evaporator may be provided. Then, the flow rate adjusting means can adjust the flow rate of the refrigerant supplied to the evaporator based on the second output.

  In this case, the flow rate adjusting means corrects the refrigerant amount based on the second output based on the output based on the temperature or pressure of the refrigerant in the vicinity of the specific suction port. For this reason, it becomes possible to improve the coefficient of performance of the refrigeration circuit by improving the conventional refrigeration circuit.

  The detection means may comprise a first temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a first pressure sensor that outputs a first output signal based on the pressure in the first temperature sensing cylinder. The second detection means may include a second temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a second pressure sensor that outputs a second output signal based on the pressure in the second temperature sensing cylinder. . The flow rate adjusting means may be an injection that changes an injection amount of the refrigerant based on the first output signal and the second output signal. In this case, the present invention is embodied by the first and second temperature sensing cylinders, the first and second pressure sensors, and the injection.

  The temperature sensitive cylinder is preferably insulated (claim 9). It is possible to prevent the pressure in the temperature sensitive cylinder from changing due to heat in the engine room, and to detect the pressure more accurately.

  Embodiments 1 to 3 embodying the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the refrigeration circuit for a vehicle according to the first embodiment includes a swash plate compressor 1 having a suction chamber 1a and a discharge chamber 1b, a condenser 5 connected by a discharge chamber 1b and a pipe 3a, and a condenser. 5 and the receiver tank 7 connected by the pipe 3b, the regulator valve 10 connected by the receiver tank 7 and the pipe 3c, the evaporator connected by the regulator valve 10 and the pipe 3d, and connected by the suction chamber 1a and the pipe 3e. 11 and a refrigerant circulating through them.

  As shown in FIGS. 2 and 3, the swash plate compressor 1 has a plurality of cylinder bores 13 a formed in a cylinder block 13. As shown in FIG. 2, the front housing 15 is in contact with the front end of the cylinder block 13, and the rear housing 19 is in contact with the rear end of the cylinder block 13 with the valve unit 17 being sandwiched between them. It is concluded by A crank chamber 23 is formed by the front housing 19 and the cylinder block 13. As shown in FIGS. 2 and 3, the rear housing 19 is formed with an annular partition wall 19a that divides the central portion and the outer peripheral portion, and the central portion of the rear housing 19 serves as a suction chamber 1a by the partition wall 19a. The outer peripheral portion of the rear housing 19 is a discharge chamber 1b. The suction chamber 1a and the discharge chamber 1b are adjacent to each other through a partition wall 19a. The front housing 15 and the cylinder block 13 correspond to a first housing, and the rear housing 19 corresponds to a second housing.

  A drive shaft 27 is rotatably supported on the front housing 15 and the cylinder block 13 via a shaft seal device 25a and bearing devices 25b and 25c. A lug plate 29 is press-fitted into the drive shaft 27 in the crank chamber 23, and a bearing device 31 is provided between the front housing 15 and the lug plate 29. In the crank chamber 23, a swash plate 33 is inserted through the drive shaft 27, and the lug plate 29 and the swash plate 33 are engaged by a hinge mechanism 35. The hinge mechanism 35 can change the inclination angle while allowing the swash plate 33 to rotate synchronously with the lug plate 29.

  In each cylinder bore 13a, a piston 37 having a piston head only in the rear is accommodated so as to be able to reciprocate. A pair of shoes 39 a and 39 b are provided between the swash plate 33 and each piston 37. Each shoe 39a, 39b has a hemispherical shape. Each of the shoes 39 a and 39 b corresponds to a motion conversion mechanism that converts the swing motion of the swash plate 33 into the reciprocating motion of each piston 37.

  Each cylinder bore 13a, each piston 37, and the valve unit 17 form a compression chamber. As shown in FIG. 3, the valve unit 17 is formed with a suction port 17a for communicating the suction chamber 1a with each compression chamber, and a discharge port 17b for communicating each compression chamber with the discharge chamber 1b. Each suction port 17a is opened and closed by a suction valve, and each discharge port 17b is opened and closed by a discharge valve. The lift amount of each discharge valve is regulated by a retainer.

  Further, as shown in FIG. 2, a suction flange 41 that extends the suction chamber 1 a to the outer peripheral side is fixed to the rear housing 19, and a pipe 3 e is connected to the suction port 41 a of the suction flange 41.

  The cylinder block 13, the rear housing 19, and the valve unit 17 are formed with an air supply passage (not shown) that connects the discharge chamber 1 b and the crank chamber 23. Further, the cylinder block 13 and the valve unit 17 are formed with an extraction passage 43 that communicates the crank chamber 23 and the suction chamber 1a. A control valve (not shown) is housed in the rear housing 19, and this control valve detects the suction pressure in a detection passage (not shown) communicating with the suction chamber 1 a, and the supply passage according to the suction pressure is detected. The opening can be changed.

  As shown in FIG. 4, the adjustment valve 10 as a flow rate adjusting means has a housing 45 communicating with the pipes 3 c and 3 d, and a valve chamber 45 a is formed in the housing 45. In the valve chamber 45a, the valve seat 45b which comprises the opening degree of the piping 3c and the piping 3c is formed. A valve body 47 is movably provided in the valve chamber 45a, and the valve body 47 is biased toward the valve seat 45b by a spring 49.

  A case 51 is coaxially and integrally fixed to the housing 45, and the inside of the case 51 is divided into two chambers, a reference chamber 51a and a detection chamber 51b, by a diaphragm 53. A valve rod 55 is fixed to the diaphragm 53. The valve rod 55 extends into the valve chamber 45 a in a state where the reference chamber 51 a is sealed, and is fixed to the valve body 47. A pressure equalizing pipe 59 is connected to the reference chamber 51a, and the pressure equalizing pipe 59 is connected in the vicinity of the outlet of the evaporator 11 as shown in FIGS.

  Further, as shown in FIG. 4, the detection chamber 51b is connected to the rear end of the capillary tube 57 as a detection means. A heat insulating tape (not shown) is wound around the capillary tube 57. As shown in FIG. 2, the tip of the capillary tube 57 is closed, and a refrigerant is hermetically sealed in the capillary tube 57 in a gas-liquid mixed state. This refrigerant is the same type as that circulating in the refrigeration circuit. As shown in FIG. 3, the tip of the capillary tube 57 is farthest from the suction port 41a and is close to the suction port 17a at a position where the refrigerant hardly flows from the suction port 41a. Hereinafter, this suction port 17a is distinguished from other suction ports 17a and is designated as a specific suction port 17s.

  In the vehicular refrigeration circuit configured as described above, as shown in FIGS. 2 and 4, the capillary tube 57 transmits a saturation pressure corresponding to the temperature of the refrigerant in the vicinity of the specific suction port 17s to the detection chamber 51b. The adjustment valve 10 adjusts the flow rate of the refrigerant supplied to the evaporator 11 based on the output of the capillary tube 57.

  More specifically, as shown in FIG. 4, if the saturation pressure of the refrigerant in the vicinity of the specific suction port 17 s is higher than the pressure on the outlet side of the evaporator 11, the valve body 47 increases the opening degree to the evaporator 11. Increase the amount of refrigerant to be supplied. Further, if the saturation pressure of the refrigerant in the vicinity of the specific suction port 17 s is lower than the pressure on the outlet side of the evaporator 11, the valve body 47 reduces the opening to reduce the amount of refrigerant supplied to the evaporator 11.

  At this time, since the regulating valve 10 is provided between the receiver tank 7 and the evaporator 11 and the evaporator 11 exists downstream of the regulating valve 10, it is easy to adjust the flow rate of the refrigerant supplied to the evaporator 11. And the cost increase of the vehicle air conditioner is also suppressed by this structure.

  For this reason, in this refrigeration circuit for a vehicle, the swash plate compressor 1 is employed, so that the refrigerant rises from the suction port 41a to the suction chamber 1a, and rises from the suction chamber 1a to each suction port 17a. Even in this case, the refrigerant having the substantially evaporating temperature is sucked into the specific cylinder bore 13a communicating with the specific suction port 17s.

  That is, as shown in FIG. 5, the superheat degree of the refrigerant sucked into the specific cylinder bore 13a is set to 0 degree. That is, the enthalpy Δhs for the degree of superheat is set to 0 for the refrigerant in the specific cylinder bore 13a.

  Further, in this vehicular refrigeration circuit, the temperature rise of the refrigerant from the intake port 41a to each intake port 17a due to a difference in the degree of heating in the engine room, a difference in the environment around the vehicle, and a difference in the traveling speed of the vehicle. Is irregular, the capillary tube 57 accurately detects the pressure for the specific suction port 17s, so that the refrigerant sucked into the specific cylinder bore 13a is also an accurate one reflecting the difference or difference. .

  Therefore, according to this vehicular refrigeration circuit, the volumetric efficiency of the swash plate compressor 1 can be improved and the power consumption can be reduced regardless of the unstable factors caused by the use in the vehicular air conditioner. Furthermore, the circulation amount of the refrigerant also increases.

  For this vehicular refrigeration circuit, the suction pressure is 0.196 MPa, the discharge pressure is 1.47 MPa, and the rotational speed of the drive shaft 27 is 1000 r. p. m. A real machine test was conducted. The cooling capacity Q, power consumption L, and coefficient of performance Q / L were determined by varying the refrigerant temperature (° C) in the vicinity of the specific suction port 17s. For comparison, the cooling capacity Q, power consumption L, and coefficient of performance Q / L of a conventional vehicle refrigeration circuit are set to 1. Other conditions were the same in the examples and comparative examples. The results are shown in FIG.

  As shown in FIG. 6, according to the vehicle refrigeration circuit of the first embodiment, the cooling capacity Q is slightly lowered by lowering the temperature of the refrigerant in the vicinity of the specific suction port 17s, but the effect of reducing the power consumption L is large. It can be seen that a high coefficient of performance Q / L can be realized.

  Further, in this vehicle refrigeration circuit, liquid compression is less likely to occur in the swash plate compressor 1, and effects such as improved durability can be obtained.

  As shown in FIG. 7, the vehicular refrigeration circuit of the second embodiment is provided with a conventional expansion valve 61 between the pipe 3c and the pipe 3d. Further, bypass pipes 3 f and 3 g as bypass passages are provided between the condenser 5 and the receiver tank 7, and the bypass pipe 3 g is connected to the suction port 41 a of the suction flange 41. An adjustment valve 10 as a flow rate adjusting means is provided between the bypass pipe 3f and the bypass pipe 3g.

  The expansion valve 61 includes a temperature sensing cylinder 61a provided at the outlet of the evaporator 11, a capillary tube 61b connected to the temperature sensing cylinder 61a, and an adjustment valve 61c connected to the capillary tube 61b. The expansion valve 61 controls the flow rate of the refrigerant based on the pressure on the outlet side of the evaporator 11 so that the degree of superheat becomes constant.

  Bypass pipes 3f and 3g are connected to the housing 45 (see FIG. 4) of the regulating valve 10, a pressure equalizing pipe 65 is connected to the reference chamber 51a (see FIG. 4), and the pressure equalizing pipe 65 is the suction chamber 1a of the rear housing 19. It is connected to the upstream part. The adjustment valve 10 can be provided in the rear housing 19. Other configurations are the same as those of the first embodiment.

  In this vehicular refrigeration circuit, the refrigerant having the saturated vapor pressure or the superheated vapor pressure that has passed through the evaporator 11 is supplied to the suction chamber 1a through the pipe 3e by adjusting the amount of refrigerant by the expansion valve 61. The suction chamber 1a is supplied with a refrigerant composed of a saturated liquid supercooled via the condenser 5 by adjusting the amount of the refrigerant by the regulating valve 10 through the bypass pipes 3f and 3g. The refrigerant of the saturated liquid is depressurized from the condensation pressure in the suction chamber 1a and absorbs heat from the suction chamber 1a. For this reason, it becomes possible to suppress the temperature rise of the refrigerant from the suction port 41a of the suction flange 41 to each suction port 17a.

  For this reason, in this vehicle refrigeration circuit, as shown in FIG. 8, the degree of superheat of the refrigerant sucked into the specific cylinder bore 13a is made negative. That is, for the refrigerant in the specific cylinder bore 13a, the enthalpy Δhs for the degree of superheat is negative. For this reason, power consumption is further reduced and the coefficient of performance is further improved.

  Further, in this vehicular refrigeration circuit, the swash plate compressor 1 can be cooled by a small amount of saturated refrigerant, so that the lubricity is improved by increasing the oil viscosity in the swash plate compressor 1 and the lip seal in the shaft seal device 25a. This reduces the temperature, reduces the thermal deformation between the piston 37 and the cylinder bore 13a, and between the shoes 39a, 39b and the piston 37, thereby improving the reliability. Other functions and effects are the same as those of the first embodiment.

  In the vehicle refrigeration circuit according to the third embodiment, as shown in FIG. 9, the capillary tube (first capillary tube) 57 according to the first embodiment is connected to a first pressure sensor 67. A similar second capillary tube 69 a is provided at the outlet of the evaporator 11, and the second capillary tube 69 a is connected to the second pressure sensor 69. The first and second pressure sensors 67 and 69 can output first and second output signals based on the pressure in the first and second capillary tubes 57 and 69a.

  An injection 71 is provided between the receiver tank 7 and the evaporator 11. The first and second output signals of the first and second pressure sensors 67 and 69 are input to the air conditioner ECU 73 of the vehicle, and the output signal of the air conditioner ECU 73 is input to the injection 71. The injection 71 can change the injection amount of the refrigerant based on the first and second output signals. The injection 71 and the air conditioner ECU 73 correspond to the flow rate adjusting means.

  In this vehicular refrigeration circuit, the first pressure sensor 69 outputs a first output signal based on the refrigerant pressure near the specific suction port 17 s, and the second pressure sensor 69 is based on the refrigerant pressure on the outlet side of the evaporator 11. A second output signal is output. Further, the air conditioner ECU 73 can calculate the enthalpy at these positions from the first and second output signals of the first and second pressure sensors 67 and 69. This difference in enthalpy is the heating amount per unit mass flow rate, which can be calculated.

  Thus, in this vehicle refrigeration circuit, the air conditioner ECU 73 corrects the refrigerant amount based on the second output signal by the first output signal. For this reason, it becomes possible to improve the coefficient of performance of the refrigeration circuit by improving the conventional refrigeration circuit.

  In this vehicular refrigeration circuit, the air conditioner ECU 73 feedback-controls the refrigerant amount by the first and second output signals of the first and second pressure sensors 67 and 69. For this reason, for example, when importance is attached to improving fuel efficiency, that is, improving the coefficient of performance, depending on the driving state of the vehicle, the volumetric efficiency of the swash plate compressor 1 is increased by reducing the degree of superheat on the outlet side of the evaporator 11. It becomes possible. Conversely, when it is desired to increase the cooling capacity, it is possible to increase the degree of superheat on the outlet side of the evaporator. Further, when the internal temperature of the swash plate compressor 1 becomes high during high speed traveling, the degree of superheat on the outlet side of the evaporator 11 can be reduced. Other functions and effects are the same as those of the first embodiment.

  In the above, the present invention has been described with reference to the first to third embodiments. However, the present invention is not limited to the first to third embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  For example, the adjustment valve 10 of the vehicle refrigeration circuit of the first and second embodiments can be configured by the injection 71 of the vehicle refrigeration circuit and the air conditioner ECU 73 of the third embodiment.

  In the first to third embodiments, the swash plate compressor 1 is a variable capacity type using a single-headed piston 37, but a fixed capacity swash plate compressor using a double-headed piston is used as a swash plate compressor. It is also possible to use a plate compressor.

  The present invention is applicable to a vehicle air conditioner.

It is a block diagram of the refrigeration circuit for vehicles of Example 1. FIG. 1 is a longitudinal sectional view of a swash plate compressor according to a vehicle refrigeration circuit of Example 1. FIG. 1 is a cross-sectional view of a swash plate compressor according to a vehicle refrigeration circuit of Example 1. FIG. 1 is a cross-sectional view of an expansion valve according to a refrigeration circuit for a vehicle according to Embodiment 1. It is a graph which shows the Mollier diagram of a certain refrigerant | coolant, and the driving | running state of the refrigeration circuit for vehicles of Example 1. FIG. It is a graph which shows the temperature of the suction inlet vicinity, COP, etc. in the refrigeration circuit for vehicles of an Example. It is a longitudinal cross-sectional view of the swash plate type compressor regarding the refrigeration circuit for vehicles of Example 2. FIG. It is a graph which shows the Mollier diagram of a certain refrigerant | coolant, and the driving | running state of the refrigeration circuit for vehicles of Example 2. FIG. 6 is a configuration diagram of a vehicle refrigeration circuit according to Embodiment 3. FIG. It is a graph which shows the Mollier diagram of a certain refrigerant | coolant, and the driving | running state of the conventional freezing circuit.

Explanation of symbols

13a ... Cylinder bore 23 ... Crank chamber 13, 15 ... First housing (13 ... Cylinder block, 15 ... Front housing) 1a ... Suction chamber 1b ... Discharge chamber 19 ... Second housing (rear housing)
27 ... Drive shaft 33 ... Swash plate 37 ... Piston 39a, 39b ... Motion conversion mechanism (shoe)
17a ... Suction port 1 ... Swash plate compressor 5 ... Condenser 11 ... Evaporator 3a, 3b, 3c, 3d, 3e, 3f, 3g ... Piping 17s ... Specific suction port 57, 67 ... Detection means (57 ... (first ) Capillary tube, 67 ... (first) pressure sensor)
10, 71, 73 ... Flow rate adjusting means (10 ... Adjustment valve, 71 ... Injection, 73 ... Air conditioner ECU)
3f ... Bypass passage (bypass pipe)
69a, 69 ... second detection means (69a ... second capillary tube, 69 ... second pressure sensor)

Claims (9)

A first housing that forms a plurality of cylinder bores and a crank chamber; a second housing that is joined to the first housing and communicates with the cylinder bores to form a suction chamber and a discharge chamber adjacent to each other; and the first housing And a drive shaft rotatably supported by the second housing, a swash plate supported by the drive shaft in the crank chamber, a piston accommodated reciprocally in each cylinder bore, and the swash plate A motion converting mechanism provided between each piston and converting a swinging motion of the swash plate into a reciprocating motion of each piston so that each cylinder bore and the suction chamber can communicate with each other by a suction port; A configured swash plate compressor,
A condenser connected to the discharge chamber;
An evaporator connected to the condenser and connected to the suction chamber;
A vehicular refrigeration circuit comprising the swash plate compressor, a refrigerant circulating between the condenser and the evaporator,
Detection means for making an output based on the temperature or pressure of the refrigerant in the vicinity of the specific suction port, which is at least one of the suction ports, in the vicinity of the specific suction port;
A vehicular refrigeration circuit, further comprising a flow rate adjusting unit that adjusts a flow rate of the refrigerant supplied to the evaporator based on the output of the detecting unit.   The vehicular refrigeration circuit according to claim 1, wherein the flow rate adjusting means is provided between the condenser and the evaporator. A bypass passage communicating with the suction chamber is provided between the condenser and the evaporator,
The vehicular refrigeration circuit according to claim 1, wherein the flow rate adjusting means is provided in the bypass passage.   The vehicular refrigeration circuit according to any one of claims 1 to 3, wherein the detecting means detects a saturation pressure of the refrigerant corresponding to a temperature of the refrigerant in the vicinity of the specific suction port. The detection means is a temperature sensitive cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state,
The vehicle according to claim 4, wherein the flow rate adjusting means is an adjustment valve that changes an opening degree of a flow path through which the refrigerant flows by opposing a pressure in the temperature sensing cylinder and a pressure on an outlet side of the evaporator. Refrigeration circuit. The detection means includes a temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a pressure sensor that outputs an output signal based on the pressure in the temperature sensing cylinder,
The vehicular refrigeration circuit according to claim 4, wherein the flow rate adjusting means is an injection that changes an injection amount of the refrigerant based on the output signal. Second detection means for performing a second output based on the temperature or pressure of the refrigerant on the outlet side of the evaporator is provided;
The vehicular refrigeration circuit according to claim 2, wherein the flow rate adjusting means adjusts the flow rate of the refrigerant supplied to the evaporator based on the second output. The detection means includes a first temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a first pressure sensor that outputs a first output signal based on the pressure in the first temperature sensing cylinder,
The second detection means includes a second temperature sensing cylinder in which the refrigerant is hermetically sealed in a gas-liquid mixed state, and a second pressure sensor that outputs a second output signal based on the pressure in the second temperature sensing cylinder. ,
The vehicular refrigeration circuit according to claim 7, wherein the flow rate adjusting means is an injection that changes an injection amount of the refrigerant based on the first output signal and the second output signal.   The vehicular refrigeration circuit according to claim 5, wherein the temperature sensitive cylinder is thermally insulated.