JP2009137504A - Refrigeration cycle device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration cycle device for a vehicle capable of exerting highly accurate detection of gas shortage with a simple configuration. <P>SOLUTION: In this refrigeration cycle for the vehicle, an air-conditioner ECU 100 estimates coolant pressure corresponding to temperature detected by a temperature sensor 84 on the downstream of an evaporator as first intake side coolant pressure, estimates second intake side coolant pressure by computing to satisfy an expression (expression 1: A×ΔPd+B×ΔPdc+Fspr=Fsol) for force balance affecting a valve body 51 taking discharge side coolant pressure detected by a discharge pressure sensor 86 as Pd, coolant different pressure detected by a flow rate sensor 40 as ΔPd, and control current driving the valve body 51 as Ic, and determines the gas shortage of the coolant when an absolute valve of the difference between an estimated value Ps1 of the first intake side coolant pressure and an estimated value Ps2 of the second intake side coolant pressure is the predetermined value or more. In the expression (expression 1), Fsol is upward electromagnetic force in the drawing affected to the valve body 51 by a movable iron core 53b by excitation to a coil 53c, A×ΔPd is downward pressing force in the drawing based on the different pressure ΔPd affected to the valve body 51 by a bellows 52b, and A is a section area of the bellows 52b affected by the different pressure ΔPd. B×ΔPdc is downward pressing force in the drawing based on the different pressure ΔPdc between a discharge chamber 9 and a crank chamber 16, and B is a section area of the valve body 51 affected by the different pressure ΔPdc. Fspr is downward supporting force in the drawing based on the predetermined spring force of the bellows 52b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular refrigeration cycle apparatus including a compressor driven by a vehicular travel engine, and particularly detects a shortage of refrigerant gas in the refrigeration cycle.

  When the refrigerant gas shortage occurs during the refrigeration cycle for vehicles, it leads to performance deterioration of the air conditioner and failure of components such as a compressor. In order to avoid such a problem, accurate detection of refrigerant gas shortage is required. There are various causes of the shortage of refrigerant gas. As an example, there is a small amount of refrigerant gas leaked from a relief valve that releases the pressure to the outside when the pressure exceeds a predetermined pressure for protection. Conventionally, there is a method of using a suction side refrigerant pressure Ps of a compressor in order to detect a refrigerant gas shortage state.

Patent Document 1 discloses a well-known configuration of a variable capacity compressor. This compressor has a capacity control valve V1 provided in the discharge chamber for controlling the pressure Pc on the crank chamber side and the pressure Pd on the discharge chamber side, the pressure Pc on the crank chamber side, and the pressure Ps on the suction chamber side. And a capacity control valve V2 provided in the suction chamber to control the crank chamber pressure Pc up to the vicinity of the variable start pressure during operation at the maximum capacity.
JP 2004-137924 A

  However, since the compressor described in Patent Document 1 uses two capacity control valves (capacity control valve V1 and capacity control valve V1), the refrigerant gas shortage is detected in the refrigeration cycle including this compressor. However, there is a problem that the configuration of the apparatus is complicated.

  In addition, a method of estimating the suction side refrigerant pressure Ps of the compressor from the fin temperature of the evaporator has been performed, but it is not possible to compare whether the Ps estimated by this method is a correct value. There is a problem that it is difficult to detect accurately.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle refrigeration cycle apparatus capable of realizing highly accurate gas shortage detection with a simple configuration.

In order to achieve the above object, the following technical means are adopted. That is, in the first invention, the compressor (1), the condenser (2), the decompression device (3), and the evaporator (4) driven by the vehicle engine (38) for sucking and discharging the refrigerant are annularly arranged. It is an invention relating to a vehicle refrigeration cycle (60, 70) configured to be connected,
A flow rate control mechanism that has a valve body (51) that adjusts the opening of the refrigerant passage (35) formed therein, and that controls the discharge capacity of the compressor (1) by driving the valve body (51). (5) and
An air conditioning control device (100) for supplying a control current (Ic) for driving the valve body (51) to control the flow rate control mechanism (5);
A discharge pressure sensor (86) for detecting the discharge side refrigerant pressure (Pd) of the compressor (1) and outputting it to the air conditioning control device (100);
An evaporator temperature detecting means (84) for detecting the outlet side temperature of the evaporator (4) and outputting it to the air conditioning control device (100);
Differential pressure detection means (40, 41) for detecting the refrigerant differential pressure (ΔPd) acting on the pressure sensitive mechanism (52) of the flow rate control mechanism (5) and outputting it to the air conditioning control device (100),
The air conditioning control device (100)
Estimating the refrigerant pressure corresponding to the temperature detected by the evaporator temperature detecting means (84) as the first suction side refrigerant pressure (Ps1),
The discharge-side refrigerant pressure (Pd) detected by the discharge pressure sensor (86), the refrigerant differential pressure (ΔPd) detected by the differential pressure detection means (40, 41), and the control current for driving the valve body (51) (Ic) is used to estimate the second suction-side refrigerant pressure by performing an operation on the balance formula (Formula 1) of the force acting on the valve body (51) (Ps2),
Further, when the absolute value of the difference between the estimated value (Ps1) of the first suction side refrigerant pressure and the estimated value (Ps2) of the second suction side refrigerant pressure is equal to or greater than a predetermined value, it is determined that the refrigerant gas is in a shortage state. It is characterized by doing.

  According to the present invention, by having both the flow rate control mechanism and the differential pressure detection means for detecting the refrigerant differential pressure acting on the pressure-sensitive mechanism part of the flow rate control mechanism, the acting force on the valve body based on the refrigerant differential pressure is reduced. In addition to being able to calculate, the estimation accuracy of the second suction side refrigerant pressure is improved, and an excellent detection of refrigerant gas shortage can be obtained. Therefore, it is possible to provide a vehicle refrigeration cycle apparatus that realizes highly accurate gas shortage detection with a simple configuration.

  In the air conditioning control device (100), the absolute value of the difference between the estimated value (Ps1) of the first suction side refrigerant pressure and the estimated value (Ps2) of the second suction side refrigerant pressure is less than a predetermined value. In some cases, it is preferable to obtain the control current (Ic) so that the forces acting on the valve body (51) are balanced, and to control the flow rate control mechanism (5) with the control current (Ic) thus calculated.

  According to the present invention, the compressor start can be strengthened by determining the variable starting current when the capacity is varied using the estimated value (Ps2) of the second suction side refrigerant pressure.

  The air conditioning control device (100) preferably uses the estimated value (Ps2) of the second suction side refrigerant pressure for the torque estimation of the compressor (1).

  According to the present invention, the torque control accuracy of the compressor 1 is improved by performing the torque estimation using the estimated value (Ps2) of the second suction side refrigerant pressure having a high estimation accuracy as described above. Can do.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means of embodiment mentioned later.

  Hereinafter, a plurality of modes for carrying out the present invention will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
1st Embodiment which is one Embodiment of this invention is described according to FIGS. FIG. 1 is a schematic diagram illustrating a schematic configuration of a vehicle refrigeration cycle apparatus 60 according to the present embodiment and an internal configuration of a compressor 1 that is a component thereof.

  A vehicular refrigeration cycle apparatus 60 used in a vehicular air conditioner includes a compressor 1 that discharges a sucked refrigerant at a high pressure, a condenser 2 into which high-pressure refrigerant discharged from a discharge port of the compressor 1 flows, An expansion valve 3 as a decompression device for decompressing and expanding the liquid refrigerant and an evaporator 4 for evaporating and evaporating the decompressed and expanded refrigerant are provided and connected in an annular shape.

  The compressor 1 is a variable capacity type in which the compression capacity is varied by a capacity control mechanism, and the compression capacity is controlled by a flow rate control valve 5 which is a refrigerant flow rate control mechanism. A front housing 8 is joined to the rear side end face of the cylinder block 6 of the compressor 1 via a valve plate 7. Inside, a discharge chamber 9, a suction chamber 10, a discharge passage 11 connected to the discharge chamber 9, and a suction passage 12 connected to the suction chamber 10 are provided. The discharge passage 11 is connected to the condenser 2 by a discharge pipe 13, and the suction passage 12 is connected to the evaporator 4 by a suction pipe 14.

  In the refrigerant passage formed by the discharge pipe 13 between the compressor 1 and the condenser 2, a fixed throttle portion 39 for obtaining a flow rate differential pressure between two points, a flow rate sensor 40 as a differential pressure detection means, Is provided. The flow sensor 40 accurately detects the flow rate differential pressure (PdL-PdLL) between the high-pressure side refrigerant (second pressure monitoring point P2) upstream of the fixed throttle 39 and the low-pressure side refrigerant (third pressure monitoring point P3) downstream. Can be detected. This flow rate differential pressure (PdL−PdLL) is substantially equal to a differential pressure ΔP (PdH−PdL) between two points at a first pressure monitoring point P1 and a second pressure monitoring point P2, which will be described later.

  Although the details of the structure of the flow sensor 40 are not shown, the high-pressure side passage 40a communicating with the discharge passage 11 through which the high-pressure side refrigerant (second pressure monitoring point P2) flows on the upstream side of the fixed throttle 39, and the low pressure A low pressure side passage 40b communicating with the passage through which the side refrigerant (third pressure monitoring point P3) flows downstream of the fixed throttle portion 39, a movable body composed of a spool sliding in the high pressure side passage 40a, and the movable body The coil spring is configured to be biased toward the high-pressure side passage 40a, a magnet provided at the tip of the movable body, and a position sensor that is disposed to face the magnet and detects the displacement of the movable body. ing.

  The flow control valve 5 is controlled by an air conditioner ECU 100 as an air conditioner control device of the present air conditioner. The compressor 1 has an electromagnetic clutch for power interruption, and the power of the engine 37 is transmitted to the compressor 1 via a V belt and an electromagnetic clutch that constitute a power transmission mechanism 38. Energization of the electromagnetic clutch is interrupted by the air conditioner ECU 100. When the electromagnetic clutch is energized and connected, the compressor 1 is in an operating state, and when the electromagnetic clutch is de-energized and opened, the compressor 1 is stopped. To do.

  Next, the internal configuration of the compressor 1 will be described with reference to FIG. A front housing 15 is joined to the front side end face of the cylinder block 6 of the compressor 1. A compartmented crank chamber 16 is formed inside the front housing 15. Between the cylinder block 6 and the valve plate 7, a suction valve forming plate 18 integrated with the suction valve 17 is provided. Between the valve plate 7 and the rear housing 8, a discharge valve forming plate 20 that is integrated with the discharge valve 19 and a retainer forming plate 22 that constitutes a retainer 21 are provided. The cylinder block 6, the front housing 15, and the rear housing 8 are fastened and fixed together by through bolts.

  The drive shaft 23 is rotatably supported by a shaft hole formed in the center portion of the cylinder block 6 and the front housing 15 via radial bearings 24a and 24b. The drive shaft 23 is operatively connected to the engine 37 via a power transmission mechanism 38 (V belt, electromagnetic clutch), and rotates upon receiving power supply from the engine 37. A lug plate 25 that can rotate in the crank chamber 16 is integrally fixed to the drive shaft 23, and a swash plate 26 that is a cam plate is disposed in a state in which the drive shaft 23 is inserted.

  The lug plate 25 and the swash plate 26 are connected by a hinge mechanism 27. The hinge mechanism 27 includes two lug plate side projections 25a projecting on the lug plate 25 so as to face the swash plate 26 side, and a swash plate side projection projecting on the swash plate 26 so as to face the lug plate 25 side. 26a. The swash plate side protrusion 26a is arranged so that the tip side enters between the two lug plate side protrusions 25a. The rotational force of the lug plate 25 is transmitted to the swash plate 26 via the lug plate side protrusion 26a and the swash plate side protrusion 26a.

  Therefore, the swash plate 26 can be rotated in synchronization with the lug plate 25 and the drive shaft 23 by being connected to the lug plate 25 by the hinge mechanism 27 and supported by the drive shaft 23. It can be tilted with respect to the drive shaft 23 while being slid in the direction.

  A piston 29 is accommodated in each of a plurality of cylinder bores 28 disposed in the circumferential direction inside the cylinder block 6 so as to be able to reciprocate. Between one end side of each piston 29 and the valve plate 7, a compression chamber 30 whose volume is changed according to the reciprocating motion of the piston 29 is formed. The other end of the piston 29 is supported on the peripheral edge of the swash plate 26 via a shoe 31.

  With the above configuration, the power of the engine 37 is transmitted to the drive shaft 23 via the power transmission mechanism 38, and when the drive shaft 23 rotates, the swash plate 26 rotates via the lug plate 25 and the hinge mechanism 27, and the shoe 31 is The piston 29 reciprocates in the cylinder bore 28. During the suction process of the piston 29, the refrigerant gas introduced from the evaporator 4 into the suction chamber 10 passes through the suction port 32, pushes the suction valve 17, and is further sucked into the compression chamber 30. When the piston 29 moves to the compression / discharge process, the refrigerant gas in the compression chamber 30 passes through the discharge port 33, pushes the discharge valve 19, and is discharged into the discharge chamber 9.

  Inside the cylinder block 6 and the rear housing 8, an extraction passage 34 that communicates the crank chamber 16 and the suction chamber 10 and an air supply passage 35 that communicates the discharge chamber 9 and the crank chamber 16 are provided. The flow control valve 5 is provided in the rear housing 8 and in the middle of the air supply passage 35.

  When the opening degree of the flow control valve 5 is adjusted by the air conditioner ECU 100, the amount of high-pressure discharged refrigerant gas introduced into the crank chamber 16 through the air supply passage 35 and the refrigerant gas from the crank chamber 16 through the extraction passage 34. The balance with the derived amount is controlled, and the internal pressure of the crank chamber 16 is determined. When the difference between the internal pressure of the crank chamber 16 via the piston 29 and the internal pressure of the compression chamber 30 changes according to the change in the internal pressure of the crank chamber 16, the inclination angle of the swash plate 26 changes, and the discharge capacity of the compressor 1. Is adjusted.

  When the internal pressure of the crank chamber 16 decreases, the inclination angle of the swash plate 26 increases and the discharge capacity of the compressor 1 increases. FIG. 1 shows a state of the maximum inclination angle in which further tilting of the swash plate 26 is restricted by the lug plate 25. Conversely, when the internal pressure of the crank chamber 16 increases, the inclination angle of the swash plate 26 decreases, the stroke of the piston 29 decreases, and the discharge capacity of the compressor 1 decreases. In this way, by adjusting the discharge capacity of the compressor 1 by changing the inclination angle of the swash plate 26, the cooling of the passenger compartment is brought into an optimum state.

  Next, the configuration of the flow control valve 5 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing the configuration of the flow control valve 5. As shown in FIG. 2, the flow control valve 5 includes a valve body 51 that adjusts the opening degree of the air supply passage 35, a pressure-sensitive mechanism 52 that is operatively connected to the valve body 51 at the top of the drawing, An electromagnetic actuator 53 operatively connected to the body 51 at the bottom of the drawing is provided inside the valve housing 54. Inside the valve housing 54, a valve hole 54a constituting a part of the air supply passage 35 is formed. When the valve body 51 moves downward, the opening degree of the valve hole 54a increases, and conversely upwards. The opening degree of the valve hole 54a is reduced by moving to.

  The pressure sensing mechanism 52 includes a pressure sensing chamber 52a formed in the upper part of the valve housing 54 and a bellows 52b which is a pressure sensing member accommodated in the pressure sensing chamber 52a. The pressure sensitive chamber 52a is partitioned by a bellows 52b into a first pressure chamber 55 that is an internal space of the bellows 52b and a second pressure chamber 56 that is an external space of the bellows 52b. The first pressure chamber 55 and the first pressure monitoring point P1 communicate with each other via the first pressure detection passage 57. Further, the second pressure chamber 56 and the second pressure monitoring point P2 communicate with each other via the second pressure detection passage 58.

  Between the first pressure monitoring point P1 and the second pressure monitoring point P2, a fixed throttle portion 36 is formed in the discharge passage 11 to increase the differential pressure ΔP (PdH−PdL) between the two points P1 and P2. Yes. As the flow rate of the refrigerant flowing through the refrigeration cycle increases, the pressure loss (differential pressure) per unit length increases. That is, the refrigerant flow rate in the refrigeration cycle can be indirectly detected by grasping the differential pressure between the two pressure monitoring points P1 and P2 (hereinafter referred to as the differential pressure ΔP between the two points). And if the fixed throttle part 36 expands the differential pressure | voltage (DELTA) P between two points, the detection of a refrigerant | coolant flow rate can be made clearer.

  With the above configuration, in the pressure sensitive mechanism 52, the pressure PdH is guided to the first pressure chamber 55, and the pressure PdL is guided to the second pressure chamber 56. The bellows 52b applies a downward pressing force to the valve body 51 based on the pressure difference ΔPd between the pressure PdH and the pressure PdL.

  The electromagnetic actuator 53 includes a fixed iron core 53a, a movable iron core 53b, and a coil 53c, and a valve body 51 is operatively connected to the movable iron core 53b. An upward electromagnetic force corresponding to the amount of electric power supplied to the coil 53c is generated between the fixed iron core 53a and the movable iron core 53b, and is further transmitted to the valve body 51 via the movable iron core 53b.

  In the flow control valve 5, the balance (balance) of the force shown in the following formula 1 is established, and the position of the valve body 51 is determined where these forces are balanced. Formula 1 is stored in advance in the microcomputer 101 of the air conditioner ECU 100.

(Formula 1)
A × ΔPd + B × ΔPdc + Fspr = Fsol
Fsol is an upward electromagnetic force that the movable iron core 53b acts on the valve body 51 by energizing the coil 53c. A × ΔPd is a downward pressure in the drawing based on the differential pressure ΔPd (the differential pressure between the refrigerant at P1 and P2 in FIGS. 1 and 2) that the bellows 52b acts on the valve body 51, and A is the differential pressure. A cross-sectional area of the bellows 52b on which ΔPd acts. B × ΔPdc is a downward pressing force based on the pressure difference ΔPdc between the discharge chamber 9 and the crank chamber 16, and B is a cross-sectional area of the valve body 51 on which the pressure difference ΔPdc acts. Fspr is a downward biasing force in the drawing based on a predetermined spring force of the bellows 52b.

  Next, a control system for a vehicle air conditioner that uses the vehicle refrigeration cycle apparatus 60 will be described. FIG. 3 is a block diagram of a control system in the vehicle air conditioner. As shown in FIG. 3, the vehicle air conditioner includes an indoor air conditioning unit disposed between the back of the instrument panel in the vehicle interior and the engine room, and each unit 90 to 93 (various doors, blowers, etc.) of the indoor air conditioning unit. ) And an air conditioner ECU 100 that can automatically control the flow rate control valve 5 and the like, which are components of the refrigeration cycle apparatus 60 for vehicles, and a control panel 80 that is operated by a passenger to set a desired operation.

  When the air conditioner ECU 100 receives the command signal transmitted from the control panel 80, the air conditioner ECU 100 can perform an air conditioning operation by performing a calculation according to a predetermined program. The air conditioner ECU 100 includes a microcomputer 101, an input circuit 102 to which signals from various switches on the control panel 80 provided in the front of the vehicle interior and sensor signals from the various sensors 40 and 81 to 87 are input, and various actuators M1. -M4 and an output circuit 103 for sending an output signal to the flow control valve 5.

  The microcomputer 101 includes a memory such as a ROM (read-only storage device) and a RAM (read-write storage device), a CPU (central processing unit), and the like, and is based on an operation command transmitted from the control panel 80 or the like. Various programs (including Formula 1) used for the calculation.

  The control panel 80 includes an air conditioner switch for commanding start and stop of the compressor 1, a suction port changeover switch for switching the suction port mode, a temperature setting switch for setting the vehicle interior temperature, and a vehicle interior by the blower 93. An air volume changeover switch for switching the air flow rate to the air outlet, an air outlet changeover switch for switching the air outlet mode, and the like are provided.

  The various sensors include an inside air temperature sensor 81 that detects the air temperature inside the vehicle interior, an outside air temperature sensor 82 that detects the outside air temperature outside the vehicle interior, a solar radiation sensor 83 that detects the amount of solar radiation irradiated into the vehicle interior, and the heat in the evaporator 4. A post-evaporator temperature sensor 84 that detects the fin temperature of the replacement core part, a water temperature sensor 85 that detects the cooling water temperature to the heater that heats the air blown inside the indoor air conditioning unit, and the discharge-side refrigerant pressure discharged from the compressor 1 A discharge pressure sensor 86 for detecting Pd, an engine speed sensor 87 for detecting the speed of the engine 37, and the like. Detection signals from these sensors are input to the air conditioner ECU 100.

  The post-evaporator temperature sensor 84 is an example of an evaporator temperature detection unit that detects the outlet side temperature of the evaporator 4, and a fin temperature sensor provided by being inserted between the fins of the heat exchange core portion of the evaporator 4. Although used, a post-evaporator air temperature sensor that detects the air temperature immediately after passing through the heat exchange core portion of the evaporator 4 may be used as another means of the evaporator temperature detecting means.

  The microcomputer 101 includes a memory such as a ROM (read-only storage device) and a RAM (read-write storage device), a CPU (central processing unit), and the like, and is based on an operation command transmitted from the control panel 80 or the like. It has various programs used for the calculation. The signal output from the microcomputer 101 is D / A converted, amplified, and the like by the output circuit 103, and then drives each of the outlet switching door 90, the inside / outside air switching door 91, the air mix door 92, and the blower 93. The actuator M1, M2, M3, M4 and the flow control valve 5 are output as drive signals.

  Next, air conditioning control processing and refrigerant gas shortage detection control by the air conditioner ECU 100 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing a main routine of air conditioning control by the air conditioner ECU 100.

  First, when an air-conditioning switch is turned on and an automatic air-conditioning operation command is input to the air-conditioner ECU 100, the air-conditioning control process is started according to the main routine shown in FIG. 4 and stored in a memory such as ROM or RAM. The control program is started and data stored in the RAM is initialized (step 10).

  Next, in step 20, the air conditioner ECU 100 controls the control panel 80, the inside air temperature sensor 81, the outside air temperature sensor 82, the solar radiation sensor 83, the post-evaporator temperature sensor 84, the water temperature sensor 85, the discharge pressure sensor 86, the flow rate sensor 40, and the engine rotation. Signals from the number sensor 87 and the like are read, and a target blowing temperature TAO of the air blown into the passenger compartment is calculated by data based on these signals and a program (calculation formula) stored in the ROM (step 30).

  Subsequently, in step 40, the air conditioner ECU 100 determines a voltage for operating the blower 93 that supplies air to the vehicle interior. This blower voltage determination process is calculated using a characteristic diagram stored in advance in the ROM.

  Next, in step 50, the air conditioner ECU 100 executes a process of determining an inlet mode corresponding to the target outlet temperature TAO calculated in step 30. The air conditioner ECU 100 determines the suction port mode using a characteristic diagram stored in advance in the ROM. For example, when the target blowing temperature TAO is higher than a predetermined target blowing temperature, the air-conditioning ECU 100 selects the inside air circulation mode and is equal to or lower than the predetermined target blowing temperature. If it is, the outside air introduction mode is selected.

  Next, in step 60, the air conditioner ECU 100 determines the outlet mode corresponding to the target outlet temperature TAO calculated in step 30 according to the characteristic chart for determining the outlet mode stored in advance in the ROM, RAM, etc. Execute the process. The air conditioner ECU 100 controls to automatically switch the blow mode of the air conditioning zone in the order of the face mode, the bi-level mode, and the foot mode as the target blow temperature TAO increases. The face mode is a mode in which conditioned air is blown out only from the face outlet, and the foot mode is a mode in which conditioned air is blown out only from the foot outlet. Further, the bar level mode is a mode in which conditioned air is blown out from the face air outlet and the foot air outlet.

  Next, the air conditioner ECU 100 calculates a target opening degree of the air mix door 92 in step 70. The degree of opening of the air mix door 92 is determined based on the target blowing temperature TAO calculated in step 30, the fin temperature after the evaporator detected by the evaporator temperature sensor 84, and the cooling water temperature detected by the water temperature sensor 85 in the ROM. It is calculated by substituting into a stored program (arithmetic expression) and performing an operation.

  Next, in step 80, the air conditioner ECU 100 calculates a target post-evaporator temperature TEO for setting the target outlet temperature TAO determined in step S30, and the detected value of the target post-evaporator temperature TEO and the post-evaporator temperature sensor 84. The target discharge amount of the compressor 1 is determined by feedback control (PI control) so that the actual post-evaporator temperature Te is equal.

  The air conditioner ECU 100 outputs a control signal to the actuators M1 to M4 so that the control states calculated or determined in the respective steps 30 to 80 are obtained, and the control current Ic that satisfies the target discharge amount of the compressor 1 Is output to the flow control valve 5 (step 90).

  Then, after executing the refrigerant gas shortage detection control (step 100), the air conditioner ECU 100 returns to the process of step 20 and repeats the above-described control process (steps 20 to 120) when a predetermined time has elapsed (step 120). By repeating such processing, air conditioning in the air conditioning zone becomes highly comfortable. Each output value follows the set value when manual operation is set.

  Next, the control (step 100) for detecting the shortage of refrigerant gas executed after step 90 will be described with reference to the flowchart shown in FIG. FIG. 5 is a flowchart showing a subroutine of refrigerant gas shortage detection control (step 100) in the present embodiment.

  First, the air conditioner ECU 100 reads the discharge-side refrigerant pressure Pd detected by the discharge pressure sensor 86 (step 101), and further reads a predetermined spring force Fspr (downward force in FIG. 2) of the bellows 52b stored in advance (see FIG. 2). Step 102).

  Next, the air conditioner ECU 100 reads the fin temperature detected by the post-evaporator temperature sensor 84, calculates a refrigerant pressure corresponding to (corresponding to) the fin temperature, and uses this to estimate the first suction side refrigerant pressure. Ps1 is set (step 103). Then, the air conditioner ECU 100 calculates and confirms the differential pressure between Pd read in step 101 and Ps1 estimated in step 103 (step 104).

  Subsequently, the air conditioner ECU 100 calculates ΔPd (the bellows 52b is a valve element) in the above equation 1 using the flow rate differential pressure (flow rate differential pressure between the refrigerant at P2 and the refrigerant at P3) detected by the flow sensor 40 provided as the differential pressure detection means. 2), A × ΔPd is calculated to obtain a pressing force (downward force in FIG. 2) based on ΔPd (step 105). Further, the air conditioner ECU 100 detects the control current Ic output to the flow control valve 5, and when the control current Ic is applied to the coil 53c, the electromagnetic force Fsol that the movable iron core 53b acts on the valve body 51 (FIG. 2). (Upward force) at (step 106).

  The air conditioner ECU 100 substitutes the predetermined spring force Fspr read in step 102, the pressing force A × ΔPd based on ΔPd calculated in step 105, and the electromagnetic force Fsol calculated in step 106 into the above-described equation 1. Thus, B × ΔPdc is obtained. Further, the air conditioner ECU 100 calculates the second suction-side refrigerant pressure, assuming that the calculated B × ΔPdc is equal to the difference between the Pd read in step 101 and the second suction-side refrigerant pressure, and calculates this as the estimated value Ps2. (Step 107).

  Next, the air conditioner ECU 100 calculates an absolute value (| Ps1-Ps2 |) of the difference between the estimated value Ps1 obtained in step 103 and the estimated value Ps2 obtained in step 107, and this absolute value is equal to or larger than a predetermined value (this value) It is determined whether or not the pressure is 0.5 MPa in the embodiment (step 108).

  If the air conditioner ECU 100 determines that | Ps1−Ps2 | calculated in step 108 is equal to or greater than a predetermined value, the air conditioner ECU 100 considers that the refrigerant gas is in a shortage state, stops the operation of the compressor 1 as a measure, and performs air conditioning. The operation is stopped (step 109).

  On the other hand, if the air conditioner ECU 100 determines that | Ps1-Ps2 | calculated in step 108 is less than a predetermined value, the refrigerant gas amount is in the normal range because the two estimated values are in a refrigerant state. Therefore, the control current Ic applied to the coil 53c is calculated so that the force shown in the above formula 1 acting on the valve body 51 is balanced, and the control current of the flow control valve 5 is adjusted to the calculated Ic (step 110). ).

  That is, the air conditioner ECU 100 calculates the predetermined spring force Fspr read in step 102, the pressing force B × ΔPdc based on ΔPdc calculated in step 104, and the pressing force A × ΔPd based on ΔPd calculated in step 105. By calculating by substituting into Equation 1, the electromagnetic force Fsol can be obtained, and the variable starting current Ic (control current when starting variable capacity) satisfying the electromagnetic force Fsol thus obtained can be calculated. .

  Following step 110, the air conditioner ECU 100 uses the estimated value Ps2 obtained in step 107 for torque estimation of the compressor 1. Then, control of the compressor 1 is executed based on this torque estimation (step 111). Thus, the torque control accuracy of the compressor 1 can be improved by using the estimated value Ps2 for torque estimation.

  As described above, the vehicle refrigeration cycle apparatus 60 according to the present embodiment has a flow rate that controls the discharge capacity of the compressor 1 by driving the valve body 51 that adjusts the opening degree of the air supply passage 35 formed therein. The control valve 5, the air conditioner ECU 100 that controls the flow rate control valve 5 by supplying the control current Ic that drives the valve body 51, and the discharge pressure sensor that detects the discharge-side refrigerant pressure Pd of the compressor 1 and outputs it to the air conditioner ECU 100. 86, a post-evaporator temperature sensor 84 that detects the outlet side temperature of the evaporator 4 and outputs it to the air conditioner ECU 100, and a flow rate sensor 40 that detects the refrigerant differential pressure ΔPd on the discharge side of the compressor 1 and outputs it to the air conditioner ECU 100. And.

  The air conditioner ECU 100 estimates the refrigerant pressure corresponding to the temperature detected by the post-evaporator temperature sensor 84 as the first suction side refrigerant pressure, the discharge side refrigerant pressure Pd detected by the discharge pressure sensor 86, and the flow rate. Using the refrigerant differential pressure ΔPd detected by the sensor 40 and the control current Ic for driving the valve body 51, the calculation is performed so as to satisfy the formula (equation 1) of the force acting on the valve body 51. Is used to estimate the second suction side refrigerant pressure, and when the absolute value of the difference between the estimated value Ps1 of the first suction side refrigerant pressure and the estimated value Ps2 of the second suction side refrigerant pressure is greater than or equal to a predetermined value, the refrigerant It is determined that the gas is in shortage.

  Thus, by having the flow rate control valve 5 and the flow rate sensor 40 that detects the refrigerant differential pressure ΔPd acting on the pressure-sensitive mechanism 52 of the flow rate control valve 5, the acting force on the valve body 51 based on the refrigerant differential pressure ΔPd. Since the estimation accuracy of the estimated value Ps2 is improved, the refrigerant gas shortage state can be accurately detected.

  Further, when the absolute value of the difference between the estimated value Ps1 of the first suction side refrigerant pressure and the estimated value Ps2 of the second suction side refrigerant pressure is less than a predetermined value, the air conditioner ECU 100 acts on the valve body 51. Is calculated, and the flow rate control mechanism (5) is controlled to the calculated control current (Ic).

  According to this control, an appropriate variable starting current can be determined, so that further protection of the compressor 1 can be achieved and responsiveness is improved.

  Further, the air conditioner ECU 100 uses the estimated value Ps2 of the second suction side refrigerant pressure for torque estimation of the compressor 1. According to this control, since the estimated value Ps2 with high estimation accuracy is used for torque estimation, the torque control accuracy of the compressor 1 can be improved, and the refrigeration cycle apparatus exhibits high performance by appropriate operation control of the compressor 1. Can be made.

(Second Embodiment)
In the second embodiment, another embodiment of the differential pressure detection means (flow rate sensor 40, fixed throttle portion 39) of the first embodiment will be described with reference to FIG. FIG. 6 is a diagram showing a schematic configuration of the vehicular refrigeration cycle apparatus 70 according to the present embodiment and an internal configuration of the compressor 1 which is one component thereof. In FIG. 6, the compressor 1 and the flow rate control valve 5 are the same as those in the first embodiment, and the same components are denoted by the same reference numerals, and the description will refer to the first embodiment. In the present embodiment, a differential pressure detection unit will be described.

  As shown in FIG. 6, in the refrigerant passage formed by the discharge pipe 13 between the compressor 1 and the condenser 2, instead of providing the differential pressure detection means, the discharge chamber 9 (first pressure monitoring point P1 ) And the pressure in the discharge passage 11 (second pressure monitoring point P2) is provided with a differential pressure detector 41 as differential pressure detecting means.

  The differential pressure detector 41 is provided so as to penetrate the rear housing 8 surrounding the discharge chamber 9 and communicate with the discharge chamber 9, and communicates with the discharge passage 11 and the high-pressure side passage 41a communicating with the first pressure monitoring point P1. By detecting the differential pressure between the refrigerant pressure passing through the high pressure side passage 41a and the refrigerant pressure passing through the low pressure side passage 41b, the low pressure side passage 41b communicating with the second pressure monitoring point P2 is provided. A differential pressure ΔPd between the pressure PdH at the first pressure monitoring point P1 and the pressure PdL at the second pressure monitoring point P2 can be detected.

  Further, in the vehicular refrigeration cycle apparatus 70 of the present embodiment, when the refrigerant gas shortage detection control of step 100 described above is performed, the basic processing is the same as that of the first embodiment, but the steps shown in FIG. Only the processing at 105 is changed as follows.

  That is, in step 105, the air conditioner ECU 100 uses the differential pressure detected by the differential pressure detector 41 (the differential pressure between the refrigerant at P1 and the refrigerant at P2) ΔPd (the difference that causes the bellows 52b to act on the valve body 51). It is read as being equal to (pressure), A × ΔPd is calculated, and the pressing force (downward force in FIG. 2) based on ΔPd is obtained.

  As described above, the vehicle refrigeration cycle apparatus 70 according to the present embodiment includes the high-pressure side passage 41a provided through the rear housing 8 surrounding the discharge chamber 9 so as to communicate with the first pressure monitoring point P1, and the second pressure. A low-pressure side passage 41b connected to the discharge passage 11 so as to communicate with the monitoring point P2, and a differential pressure ΔPd (= PdH−PdL) between the first pressure monitoring point P1 and the second pressure monitoring point P2. A differential pressure detector 41 is provided.

  With this configuration, the distance between the discharge chamber side inlet of the high pressure side passage 41a and the discharge passage side inlet of the low pressure side passage 41b can be set to be long. There is no need to newly provide a throttle portion between 41a and the low pressure side passage 41b.

  Therefore, since the number of parts can be reduced, the configuration can be simplified, and the number of throttle parts for detecting the differential pressure can be reduced, so that a pressure loss is reduced and a refrigeration cycle apparatus that suppresses a reduction in refrigeration capacity can be obtained. . In the above configuration, since there is no throttle portion between the high pressure side passage 41a and the low pressure side passage 41b, the differential pressure ΔPd (= PdH−PdL) between the first pressure monitoring point P1 and the second pressure monitoring point P2 is directly detected. Therefore, the acting force on the valve body 51 based on the differential pressure can be detected with higher accuracy, and the detection accuracy of the estimated value Ps2 and the insufficient detection of the refrigerant gas is improved.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

Vehicle refrigeration cycle apparatus described in the above embodiment is one in which various refrigerants (Freon refrigerants, HC-based refrigerant, CO ₂ refrigerant) in the case of using a advantageous effects described above. For example, when a CO ₂ refrigerant is used, the vehicular refrigeration cycle apparatus is a supercritical refrigeration cycle apparatus in which the refrigerant is compressed to a critical pressure or higher by the compressor 1. And the condenser 2 functions as a radiator, and the refrigerant cooled by the radiator does not condense.

It is the schematic which showed schematic structure of the refrigeration cycle apparatus for vehicles in 1st Embodiment which is one Example of this invention, and the internal structure of the compressor which is the one component. It is sectional drawing which showed the structure of the flow control valve provided in the compressor of FIG. It is a control block diagram of the vehicle air conditioner which uses the refrigeration cycle apparatus for vehicles of 1st Embodiment. It is a flowchart which shows the flow of the main routine of the air-conditioning control in the vehicle air conditioner in 1st Embodiment. It is a flowchart which shows the flow of the refrigerant gas shortage detection control in 1st Embodiment. It is the figure which showed schematic structure of the refrigeration cycle apparatus for vehicles in 2nd Embodiment, and the internal structure of the compressor which is the one component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Condenser 3 ... Expansion valve (pressure reduction device)
4 ... Evaporator 5 ... Flow control valve (flow control mechanism)
35 ... Air supply passage (refrigerant passage)
38 ... Engine 40 ... Flow rate sensor (Differential pressure detection means)
41 ... Differential pressure detector (Differential pressure detector)
DESCRIPTION OF SYMBOLS 51 ... Valve body 52 ... Pressure-sensitive mechanism part 60,70 ... Vehicle refrigeration cycle apparatus 84 ... Evaporator post-temperature sensor (evaporator temperature detection means)
86: Discharge pressure sensor 100 ... Air conditioner ECU (air conditioner control device)

Claims (3)

For a vehicle constructed by connecting a compressor (1), a condenser (2), a pressure reducing device (3), and an evaporator (4) that are driven by a vehicle engine (38) and suck and discharge refrigerant. A refrigeration cycle (60, 70),
A flow rate that has a valve body (51) for adjusting the opening of the refrigerant passage (35) formed therein, and controls the discharge capacity of the compressor (1) by driving the valve body (51). A control mechanism (5);
An air conditioning controller (100) for supplying a control current (Ic) for driving the valve body (51) to control the flow rate control mechanism (5);
A discharge pressure sensor (86) for detecting the discharge-side refrigerant pressure (Pd) of the compressor (1) and outputting it to the air conditioning control device (100);
An evaporator temperature detecting means (84) for detecting an outlet side temperature of the evaporator (4) and outputting the detected temperature to the air conditioning control device (100);
Differential pressure detection means (40, 41) for detecting the refrigerant differential pressure (ΔPd) acting on the pressure-sensitive mechanism (52) of the flow rate control mechanism (5) and outputting it to the air conditioning control device (100); Prepared,
The air conditioning control device (100)
Estimating the refrigerant pressure corresponding to the temperature detected by the evaporator temperature detecting means (84) as the first suction side refrigerant pressure (Ps1),
The discharge-side refrigerant pressure (Pd) detected by the discharge pressure sensor (86), the refrigerant differential pressure (ΔPd) detected by the differential pressure detection means (40, 41), and the valve body (51) The control current (Ic) that drives the valve body (51) is used to calculate the force balance acting on the valve body (51) (Formula 1), thereby calculating the second suction side refrigerant pressure. Estimate (Ps2),
Further, when the absolute value of the difference between the estimated value (Ps1) of the first suction side refrigerant pressure and the estimated value (Ps2) of the second suction side refrigerant pressure is equal to or greater than a predetermined value, it is determined that the refrigerant gas is in a shortage state. A refrigeration cycle device for vehicles characterized by the above.   When the absolute value of the difference between the estimated value (Ps1) of the first suction side refrigerant pressure and the estimated value (Ps2) of the second suction side refrigerant pressure is less than a predetermined value, the air conditioning control device (100) The control current (Ic) is obtained so that the forces acting on the valve body (51) are balanced, and the flow rate control mechanism (5) is controlled by the obtained control current (Ic). Item 2. The vehicle refrigeration cycle apparatus according to Item 1.   The said air-conditioning control apparatus (100) uses the estimated value (Ps2) of the said 2nd suction | inhalation side refrigerant | coolant pressure for the torque estimation of the said compressor (1), The object for vehicles of Claim 1 or 2 characterized by the above-mentioned. Refrigeration cycle equipment.

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