JP2008261603A - Refrigerating cycle device and air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device capable of suppressing insufficient oil return and blowoff temperature variation caused by the rotating speed difference of a compressor in forced intermittent control of the compressor and to provide an air conditioner for a vehicle. <P>SOLUTION: The refrigerating cycle device is provided with a storage means 160 storing a plurality of control modes set according to the rotating speed Nc of the compressor 142 so that at least one of parameters of a stop time h, a working time H and intermittent frequency n of the compressor 142 in forced intermittent control differs, a selecting means for selecting one control mode based on the rotating speed Nc of the compressor 142 (S140, S150, S160), and a control means for performing forced intermittent control in the selected control mode (S170). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus having first and second evaporators provided in parallel, and in particular, a front seat side air conditioning unit that air-conditions a region on the front seat side of the vehicle interior, and a region on the rear seat side of the vehicle interior It is suitable to be applied to a vehicle air conditioner including a rear seat side air conditioning unit for air conditioning.

  Conventionally, as shown in Patent Document 1, a front seat side air conditioning unit that air-conditions a region on the front seat side of the vehicle interior and a rear seat air conditioning unit that air-conditions the region on the rear seat side of the vehicle interior, 2. Description of the Related Art A solenoid valveless dual air conditioner type vehicle air conditioner that eliminates a solenoid valve that interrupts the flow of refrigerant to an evaporator is known.

  In this vehicle air conditioner, an evaporator is provided independently for each of the front seat side and the rear seat side, and the compressor and the condenser are commonly used. In particular, in the rear seat side evaporator, a temperature type expansion valve that controls the degree of superheat of the refrigerant on the outlet side of the evaporator to a predetermined value is used.

  In such a dual air conditioner system, when the front seat side is operated independently, the temperature expansion valve of the rear seat side evaporator repeatedly opens and closes slightly.Therefore, in the rear seat side evaporator and the low pressure pipe, Lubricating oil mixed in the refrigerant tends to accumulate, and there is a problem that the amount of oil returning to the compressor is insufficient and the durability of the compressor is adversely affected.

  Therefore, in the vehicle air conditioner described in Patent Document 1, the low-pressure pressure is forcibly changed by forcibly interrupting the compressor operation a predetermined number of times after a predetermined time has elapsed since the compressor is operated. By forcibly opening the rear seat side expansion valve of the side evaporator, the oil accumulated in the rear seat side evaporator and the low pressure pipe is returned to the compressor suction side.

In this system, the occupant feels uncomfortable due to fluctuations in the blowing temperature at the maximum airflow of the front seat blower at the idling speed where the improvement (increase) in the oil circulation rate due to fluctuations in the compressor speed is the most severe. The clutch-off time, the clutch-on time, and the number of on / off times are determined so that there is no possibility.
JP 2000-283576 A

  However, when the engine is running at high speed, the temperature fluctuation due to the intermittent operation of the compressor is larger than when idling. Therefore, if the forced intermittent control is performed at the same time as when idling, the temperature fluctuation will increase. There has been a problem of discomfort.

  In view of the above problems, an object of the present invention is to provide a refrigeration cycle apparatus and a vehicle air conditioner capable of suppressing oil return shortage and blowout temperature fluctuation caused by a difference in the rotation speed of the compressor in forced intermittent control of the compressor. It is in.

  In order to achieve the above object, the present invention employs the following technical means.

  In the first aspect of the invention, the compressor (142) that compresses and discharges the refrigerant, the condenser (143) that cools and condenses the refrigerant discharged from the compressor (142), and the condenser (143). A first decompression means (114) for decompressing and expanding the condensed refrigerant; a first evaporator (113) for mainly evaporating the refrigerant decompressed and expanded by the first decompression means (114); A second decompression means (124) connected in parallel with the decompression means (114) and decompressing and expanding the refrigerant condensed in the condenser (143) is selectively used and in parallel with the first evaporator (113). And a second evaporator (123) for evaporating the refrigerant decompressed and expanded by the second decompression means (124), and at least the second decompression means of the first and second decompression means (114, 124). (124) In the refrigeration cycle apparatus formed as a temperature type expansion valve (124) that adjusts the degree of superheat of the outlet refrigerant of the second evaporator (123), the compressor (142) is forcibly stopped and forced to intermittently operate. The rotation speed (Nc) of the compressor (142) so that at least one of the parameters of the stop time (h), the operation time (H), and the number of interruptions (n) of the compressor (142) in the control is different. ), A storage unit (160) that stores a plurality of control modes set according to the control unit, and a control mode stored in the storage unit (160). Selection means (S140, S150, S160) and selection means (S140, S150) for selection based on the rotational speed (Nc) of the compressor (142) when a predetermined time (tx) has elapsed since the drive In the control mode selected by S160), characterized in that it comprises a control means for performing forced off control (S170).

  In the refrigeration cycle apparatus in which the temperature expansion valve (124) is used as the second pressure reducing means (124) of the second evaporator (123), as described in the background section, only the first evaporator (113) is used. When oil is used, lubricating oil tends to accumulate in the second evaporator (123) or in the low-pressure pipe.

  Therefore, it is possible to return the lubricating oil by applying forced on / off control (corresponding to one step in oil return control) to the compressor (142). According to the first aspect of the present invention, since the control mode corresponding to the rotational speed (Nc) of the compressor (142) is selected and executed, a suitable forcing is selected according to the rotational speed Nc of the compressor (142). Intermittent control can be performed, and insufficient oil return and blowout temperature fluctuations caused by differences in the rotational speed of the compressor (142) can be suppressed as much as possible.

  In the second aspect of the invention, the control mode when the rotational speed (Nc) of the compressor (142) is large when the predetermined time (tx) has elapsed is compared with the control mode when the rotational speed (Nc) is small. Thus, the value of at least one parameter of the stop time (h) of the compressor (142) and the number of intermittent times (n) of the compressor (142) is set to be small.

  When the compressor (142) is rotating at a high speed, the oil return performance (the degree of increase in the oil circulation rate) during forced on / off control of the compressor is better than when the compressor (142) is rotating at a low speed. is there. By setting the stop time (h) or (and) the number of intermittent times (n) of the compressor (142) to be small, it is possible to reduce the blowout temperature fluctuation at the time of high rotation.

  In the invention according to claim 3, the control mode includes a low rotation mode in which the rotation speed (Nc) of the compressor (142) is equal to or less than a predetermined value, and a rotation speed (Nc) of the compressor (142) from a predetermined value. The predetermined high value is set in the range of 1000 to 1800 rpm.

  By setting the predetermined value in a range of 1000 to 1800 rpm, it is possible to clearly distinguish between idling and traveling, and the above control can be suitably performed.

  In the fourth aspect of the invention, the plurality of control modes having the first blower (112) for blowing air to the first evaporator (113) and stored in the storage means (160) are the compressor (142). The number of rotations (Nc) and the blower level indicating the blower level of the first blower (112) are associated with each other, and the selection means (S140, S150, S160) are selected after the compressor (142) is driven. One of the control modes is selected based on the rotational speed (Nc) and the blower level of the compressor (142) when the predetermined time (tx) has elapsed.

  According to this, in addition to the rotational speed (Nc) of the compressor (142), the control mode corresponding to the blower level is selected, so that more precise control can be performed.

  According to the fifth aspect of the present invention, the control mode when the blower level is high when the predetermined time (tx) has elapsed is longer than the stop time (h) of the compressor (142) compared to the control mode when the blower level is low. Is set to be short.

  When the blower level is large, the temperature fluctuation of the blowout becomes large. In addition, the longer the stop time (h), the greater the variation in the blowing temperature. Therefore, the larger the blower level is, the shorter the stop time (h) can be set, so that the blowout temperature fluctuation can be reduced.

  In the invention according to claim 6, in the relationship between the time after the compressor (142) is driven and the rotational speed (Nc) of the compressor (142), the ratio of the time when the rotational speed (Nc) is small is high. The control means (S170) has control start time adjusting means (S111 to S115, S116, S117) for adjusting the time until the forced intermittent control is started longer than the case where the ratio is low. The forced on / off control is performed after elapse of the time adjusted by the control start time adjusting means (S111 to S115, S116, S117).

  According to this, for example, the frequency of the forced intermittent control at the time of idling (at the time of low rotation of the compressor (142)) where the rate of decrease in the oil circulation rate is slow can be reduced, and efficient control can be performed. As a result, the durability of the compressor (142) can be improved.

  In the seventh aspect of the invention, the control start time adjusting means (S111 to S115, S116, S117) is a timer measurement value when the rotation speed (Nc) of the compressor (142) is lower than a predetermined threshold value. Based on a certain low rotation timer count value (t1) and a high rotation timer count value (t2) that is a timer measurement value when the rotation speed (Nc) of the compressor (142) is equal to or greater than a threshold value, mixing in the refrigerant An oil circulation rate reduction value calculating means (S114) for calculating an oil circulation rate reduction value indicating a reduction value of the oil circulation rate, which is a ratio of the lubricating oil circulated together with the refrigerant, and an oil circulation rate reduction value calculation means (S114) ) And an oil circulation rate lowering value judging means (S115) for judging whether or not the oil circulation rate lowering value calculated by the above is equal to or higher than a predetermined value, and a control means (S170). , And performs forced off control when the value decreased oil circulation rate by oil circulation rate reduction value determining means (S115) is determined to be greater than or equal to the prescribed value.

  According to this, by calculating the oil circulation rate decrease value based on the low rotation timer count value (t1) and the high rotation timer count value (t2), the time until the forced intermittent control is simply and suitably extended. be able to.

  In the invention according to claim 8, the control start time adjusting means (S111 to S115, S116, S117) is a timer measurement value when the rotation speed (Nc) of the compressor (142) is lower than a predetermined threshold value. A certain low rotation timer count value (t1) and a high rotation timer count value (t2), which is a timer measurement value when the rotation speed (Nc) of the compressor (142) is equal to or greater than a threshold, ) Is multiplied by a constant corresponding to the number of revolutions (Nc), and a value calculated by multiplication is added to a conversion time calculation means (S116) for calculating a conversion time and a conversion time calculation means (S116). Conversion time determining means (S117) for determining whether or not the converted time is equal to or longer than a predetermined time (tx), and the control means (S170) includes conversion time determining means. Convert time due S117) is characterized by performing the forced off control when it is determined that the predetermined time (tx) or more.

  According to this, by calculating the conversion time based on the low rotation timer count value (t1) and the high rotation timer count value (t2), it is possible to easily and suitably extend the time until the forced intermittent control. .

  According to the ninth aspect of the present invention, the compressor (142) is a fixed capacity type compressor (142) having an electromagnetic clutch (141), and the control means (S170) turns the electromagnetic clutch (141) on and off. Forcible intermittent control is performed by switching between.

  According to this, oil return can be easily performed by the on / off control of the electromagnetic clutch (141).

  In the invention of claim 10, the front seat side air conditioning unit (110) for air conditioning the front seat side of the vehicle interior, the rear seat side air conditioning unit (120) for air conditioning the rear seat side of the vehicle interior, and claims 1 to The refrigeration cycle apparatus according to any one of Items 9 is provided, the first evaporator (113) is disposed in the front seat air conditioning unit (110), and the second evaporation is performed in the rear seat air conditioning unit (120). A device (123) is arranged.

  Thereby, in a dual air conditioner type vehicle air conditioner, temperature fluctuations can be suppressed while solving the shortage of oil return to the compressor (142) due to the independent operation of the front seat air conditioning unit (110). .

(First embodiment)
Hereinafter, the refrigeration cycle apparatus (vehicle air conditioner) 100 according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an overall system configuration diagram of a refrigeration cycle apparatus showing a first embodiment of the present invention. As shown in FIG. 1, the refrigeration cycle apparatus 100 is mounted on a vehicle 10 that uses an engine as a driving source for traveling, and performs cooling (air conditioning) of the passenger compartment. The refrigeration cycle apparatus 100 includes a front seat air conditioning unit 110, a rear seat air conditioning unit 120, a control device 160 (see FIG. 2), and the like.

  The front seat side air conditioning unit 110 is disposed inside the foremost instrument panel (not shown) in the passenger compartment 11 and air-conditions a region on the front seat side of the passenger compartment. The front seat side air conditioning unit 110 has a case 111 that forms an air passage, and a blower 112 is disposed upstream of the case 111. The blower 112 blows the inside air or outside air that is switched and introduced from an inside / outside air switching box (not shown).

  A front seat side evaporator (first evaporator) 113 of the refrigeration cycle R is arranged downstream of the blower 112 as a cooling heat exchanger for cooling the blown air. Here, the refrigeration cycle R has a well-known configuration and includes a compressor 142 that is driven by a vehicle engine (not shown) via an electromagnetic clutch 141. The refrigerant is compressed to high temperature and high pressure by the compressor 142, and the gas refrigerant discharged from the compressor 142 is introduced into the condenser 143, where the gas refrigerant is outside air blown by the front seat side blower 144. Exchanges with heat to condense.

  The refrigerant that has passed through the condenser 143 is separated into a liquid phase refrigerant and a gas phase refrigerant by a liquid receiver (not shown), and the liquid phase refrigerant is stored in the liquid receiver. The liquid refrigerant from the liquid receiver is decompressed to a low-pressure gas-liquid two-phase refrigerant by a front seat side temperature type expansion valve 114 (hereinafter referred to as “front seat side expansion valve”). The front seat evaporator 113 absorbs heat from the conditioned air and evaporates.

  As is well known, the front seat side expansion valve 114 automatically adjusts the valve opening so that the refrigerant superheat degree at the outlet of the front seat evaporator 113 is maintained at a predetermined value. Therefore, the temperature type expansion valve 114 includes a temperature sensing part (not shown) that senses the refrigerant temperature at the outlet of the evaporator 113, and a first pressure chamber (not shown) to which a pressure corresponding to the refrigerant temperature sensed by the temperature sensing part is applied. (Not shown), a second pressure chamber (not shown) to which the refrigerant pressure (cycle low pressure) of the evaporator 113 is applied, and a diaphragm (not shown) that partitions the first and second pressure chambers. The diaphragm and the valve body are displaced in accordance with the pressure difference between the two pressure chambers and the spring force to adjust the refrigerant flow rate. For example, when the refrigerant temperature sensed by the temperature sensing unit increases, the diaphragm and the valve body are displaced to increase the valve opening, and the refrigerant flow rate to the evaporator is increased.

  The gas refrigerant evaporated in the evaporator 113 is again sucked into the compressor 142 and compressed. In the refrigeration cycle R, devices such as the compressor 142 and the condenser 143 are mounted in the engine room 12 on the front side of the vehicle compartment 11. In the front seat side air conditioning unit 110, a temperature sensor 115 is disposed in the air blowing portion of the evaporator 113, and when the blowing temperature te (evaporator cooling temperature) detected by the temperature sensor 115 falls below a predetermined value, The energization of the electromagnetic clutch 141 is cut off and the operation of the compressor 142 is stopped to prevent the evaporator 113 from being frosted.

  In the case 111 of the front seat side air conditioning unit 110, on the downstream side of the front seat side evaporator 113, a heater core (not shown) that heats the conditioned air with hot water from the vehicle engine, is heated through the heater core. An air mix door (not shown) that adjusts the air volume ratio between the hot air and the cold air that bypasses the heater core to adjust the blowing temperature is disposed. And the defroster blowing opening part, the front seat side face blowing opening part, and the front seat side foot blowing opening part (all are not shown in figure) are opening in the downstream end of the case of the front seat side air conditioning unit 110. The opening is switched and opened by a blowing mode door (not shown) so that the conditioned air that has passed through each opening is blown toward the inner surface of the vehicle window glass, the head of the front seat occupant, and the feet. It has become.

  Note that the mode for blowing air conditioning from the front seat face outlet opening is FACE mode, the mode for blowing air conditioning from the front seat face opening and front seat foot opening is B / L mode, front seat side The FOOT (foot) mode is the mode that blows air conditioning from the foot outlet opening, the F / D mode that blows air conditioning from the front seat foot opening and the defroster opening, and the DEF mode that blows air conditioning from the defroster opening is DEF ( Defroster) mode. In the present embodiment, it is assumed that the FACE mode or the B / L mode in which the blowout temperature variation is relatively large is selected as a premise.

  Next, the rear seat air conditioning unit 120 will be described. The rear seat side air conditioning unit 120 is disposed in a rear portion of the passenger compartment 11, for example, a side portion of the rear seat, and air-conditions the rear seat side of the passenger compartment. In the case 121 of the rear seat side air conditioning unit 120, a blower 122 that sucks and blows inside air is provided, and a rear seat side evaporator 123 (second evaporator) is disposed downstream of the blower 122. Yes.

  A rear-seat temperature expansion valve 124 (hereinafter simply referred to as “rear-seat-side expansion valve”) is provided at the refrigerant inlet of the rear-seat evaporator 123. The rear seat side expansion valve 124 is the same as the front seat side expansion valve 114, and decompression means for decompressing the high-temperature and high-pressure liquid refrigerant from the liquid receiver (not shown) into a low-temperature and low-pressure gas-liquid two-phase refrigerant. Therefore, the flow rate of the refrigerant is adjusted by adjusting the valve opening so that the degree of superheat of the refrigerant at the outlet of the rear seat evaporator 123 becomes a predetermined value set in advance.

  In the refrigeration cycle R, the inlet side of the rear seat side expansion valve 124 is connected to the inlet side of the front seat side expansion valve 114 via the underfloor high-pressure pipe 151, and the outlet side of the rear seat side evaporator 123 is below the floor. The low pressure pipe 152 is connected to the outlet side of the front seat side evaporator 113. Thus, the rear seat side evaporator 123 and the rear seat side expansion valve 124 are connected in parallel with the front seat side evaporator 113 and the front seat side expansion valve 114.

  Since the underfloor high-pressure pipe 151 and the underfloor low-pressure pipe 152 are disposed in the underfloor space formed below the floor surface 11a of the passenger compartment 11, the predetermined height L (for example, about 600 mm) is higher than the suction pipe of the compressor 142. It is arranged at the lower part only.

  In the rear seat air conditioning unit 120, a heater core (not shown) that heats the conditioned air with warm water from the vehicle engine is disposed downstream of the evaporator 123. In the rear seat air conditioning unit 120, a rear seat face blowing opening (not shown) and a blowing mode door (not shown) are arranged at the downstream end of the case 121 and cooled by the rear seat evaporator 123. The cool air is blown out from the rear seat face blowing opening through the rear seat face duct (not shown) from the ceiling outlet (not shown) toward the head of the rear seat occupant.

  FIG. 2 is a schematic block diagram showing the electric control unit of the present embodiment. As shown in FIG. 2, an air conditioning control device (air conditioner ECU) 160 constitutes the storage means, selection means, and control means of the present invention, and includes a CPU, a ROM, a RAM (all not shown), and the like. It consists of a known microcomputer and its peripheral circuits. The ROM stores a control program for air conditioning control and oil return control described later, and performs various calculations and processing based on the control program. Further, the air conditioner ECU 160 has a known timer function.

  In the present embodiment, in the ROM, two types of control modes (low rotation mode and high rotation mode) corresponding to the rotational speed Nc of the compressor 142 are provided in the ROM with respect to forced intermittent control which is one step in oil return control. It is remembered. In setting the detailed contents of each control mode, that is, the stop time h of the compressor 142 (= the clutch off time of the electromagnetic clutch 141), the operation time H (= the clutch on time of the electromagnetic clutch 141), and the number of intermittent times n. The detailed description will be given later.

  The air conditioner ECU 160 includes a rear seat side evaporator outlet temperature sensor 115, a compressor rotational speed sensor 162, a rear seat air conditioner panel 163, and a front seat air conditioner panel 164 (blower level switch 165, outlet position switch 166, air conditioner switch 167). Etc. are connected. And detection signals, such as a front seat side evaporator blowing temperature te and the rotation speed Nc of the compressor 142, are input.

  Also, from the front seat air-conditioner panel 164, blower level (7 steps of Lo, M1 to M5, Hi in order of increasing air volume), blowing position (FACE mode, B / L mode, FOOT mode, F / D mode, defroster) Mode) and an air conditioner switch ON / OFF operation signal is input. Note that an air conditioner permission signal is transmitted to the air conditioner ECU 160 when the air conditioner switch is turned on by the passenger and the blower level switch is turned on. On the other hand, substantially the same operation signal is also input from the rear seat side air conditioner panel 163. The rear seat side operation signals can also be input from the front seat side air conditioning panel 164.

  The air conditioner ECU 160 is linked to an engine control device (engine ECU 170), and an engine speed sensor 171, an accelerator opening sensor 172, a cooling fan 173, and the like are connected to the engine ECU 170.

  Then, the air conditioner ECU 160 performs a predetermined calculation process according to a preset program based on each input signal and outputs an output signal, and the compressor 142 (electromagnetic clutch 141), the front seat fan 112, and the rear seat fan 122. The operation of each motor 153 for driving various doors is controlled.

  Next, the operation based on the above configuration will be described. First, when both the front seat side air conditioning unit 110 and the rear seat side air conditioning unit 120 are operated, both the front and rear blowers 112 and 122 are operated to blow air to both the air conditioning units 110 and 120. When the air conditioner switch 167 (compressor operation switch) of the front seat side air conditioner panel 164 is turned on, the electromagnetic clutch 141 is energized and connected, so that the compressor 142 is driven by the vehicle engine.

  Thereby, in the front seat side air conditioning unit 110, the blown air is cooled and dehumidified by the front seat side evaporator 113 and blown out as cold air to the front seat side space in the passenger compartment 11. Similarly, in the rear seat air conditioning unit 120, the blown air is cooled and dehumidified by the rear seat evaporator 123, and blown out as cold air to the rear seat side space in the passenger compartment 11.

  When both the front and rear air conditioning units 110 and 120 are operated simultaneously, the front and rear expansion valves 114 and 124 are adjusted to the degree of valve opening corresponding to the cooling heat load of the front and rear evaporators 113 and 123, respectively. , 124 always allows the refrigerant having a flow rate corresponding to the cooling heat load to pass through the flow paths of the evaporators 113, 123.

  On the other hand, when the occupant is in the front seat only and the occupant is not in the rear seat, the rear seat blower 122 can be stopped by a switch operation on the air conditioning panel 164 for the front seat. As a result, no air is blown to the rear seat air conditioning unit 120, the rear seat expansion valve 124 is fully closed, and the air conditioning operation of the rear seat air conditioning unit 120 is stopped. Only the air conditioning unit 110 is in a single operation state.

  During the independent operation of the front seat air conditioning unit 110, since the air blowing to the rear seat evaporator 123 is stopped, the liquid refrigerant accumulated in the rear seat evaporator 123 gradually evaporates. When the evaporation of is completed, the temperature of the rear-seat-side evaporator 123 rises toward the ambient atmosphere temperature (room temperature).

  Therefore, the temperature of the temperature sensing part of the rear seat side expansion valve 124 serving as a decompression unit of the rear seat side air conditioning unit 120 also rises toward the ambient temperature (room temperature), and the rear seat side evaporator 123 in this temperature rise process. As the degree of superheat of the outlet refrigerant increases, the valve element of the rear seat side expansion valve 124 opens by a minute opening. Then, the low-pressure refrigerant that has passed through the rear seat side expansion valve 124 flows into the rear seat evaporator 123.

  As a result, the evaporation of the liquid refrigerant is resumed in the rear seat side evaporator 123, and the temperature of the evaporator 123 (the degree of superheat of the refrigerant) decreases. Return to the fully closed state. Then, after the rear seat side expansion valve 124 is fully closed, when time elapses and the evaporation of the refrigerant is completed and the degree of refrigerant superheat rises, the valve body of the rear seat side expansion valve 124 opens again by a minute opening degree.

  In this way, during the front seat side independent operation, the rear seat side expansion valve 124 repeatedly opens and closes slightly, but the rear seat side rear seat expansion valve 124 opens when the rear seat side minute valve is opened. Lubricating oil also flows into the side evaporator 123 together with the refrigerant. At this time, the refrigerant evaporates and becomes gaseous, and is sucked into the compressor 142. However, the lubricating oil has a much higher evaporation temperature than the refrigerant and does not evaporate.

  Since the liquid-phase lubricating oil cannot be pushed downstream by the minute flow generated by the minute opening of the rear seat side expansion valve 124, the liquid-phase lubricating oil is below the floor of the evaporator 123 or the outlet of the evaporator 123. It accumulates in the low pressure pipe 152. In particular, the low-floor low-pressure pipe 152 at the outlet of the rear-seat evaporator 123 is often arranged at a position that is approximately 600 mm lower than the suction port of the compressor 142. The lubricating oil tends to accumulate in 152. The phenomenon that the lubricating oil accumulates in a certain part in the refrigeration cycle R is hereinafter referred to as “oil stagnation”.

  Therefore, in this embodiment, in order to eliminate the oil stagnation phenomenon, oil return control is adopted in which the operation of the compressor 142 is forcibly interrupted at predetermined time intervals to increase the oil circulation rate. The oil circulation rate in the refrigeration cycle is a value defined by the amount of lubricating oil / (the amount of lubricating oil + the amount of refrigerant) × 100 (%).

  FIG. 3 is a flowchart illustrating oil return control executed by the control unit (air conditioner ECU 160) in the first embodiment. This control routine starts when the engine is started. First, in step S100, the timer constant t is reset (t = 0). In step S110, it is determined from the signal from the air conditioner switch 167 whether the air conditioner is on. If the air conditioner is on (S110: YES), a timer count is started in step S120.

  Next, in step S130, it is determined whether the timer time t (the time from when the air conditioner permission signal is input to the air conditioner ECU 160) t is equal to or greater than the predetermined time tx. If the timer time t is equal to or greater than the predetermined time tx (S130: YES), whether or not the rotational speed Nc of the compressor 142 detected from the compressor rotational speed sensor 162 is 1100 rpm or less in step S140. Judge.

  When the rotation speed Nc is 1100 rpm or less (step S140: YES), in step S150, the low rotation mode is set out of the two control modes of forced intermittent control. On the other hand, when the rotation speed Nc is higher than 1100 rpm (step S140: NO), in step S160, the high rotation mode is set out of the two control modes of forced intermittent control.

  After setting to each control mode, in step S170, forced on / off control of the compressor 142 is executed with the contents set in each mode. After execution, the process returns to step S100 to clear the timer count and reset the constant (t = 0).

  In the control described above, if the air conditioner is not in the on state (ie, S110: NO in the off state) in step S110, the process returns to step S100 and this process is repeated until the air conditioner is turned on. In step S130, if the timer time t is smaller than the predetermined time tx, that is, if the predetermined time tx has not elapsed (S130: NO), the process returns to step S110 again, and whether or not the air conditioner is on. Is judged.

  FIG. 4 is a time chart showing the operation of the compressor, the oil circulation rate, and the blowing temperature in the forced on / off control of the compressor 142. 4A is an operation explanatory diagram in the low rotation mode, and FIG. 4B is an operation explanatory diagram in the high rotation mode.

  In explaining the operation, first, in the present embodiment, a concept for setting a predetermined time tx for determining an operation interval of forced on / off control, a clutch off time h for forced on / off control, a clutch on time H, and an on / off number n Specific numerical examples will be described.

  First, the predetermined time tx of the operation interval will be described. After the air conditioner switch 167 (compressor operation switch) of the front seat side air conditioner panel 164 is turned on, when the front seat side single operation is set in addition to the compressor 142 continuously operating, the oil to the underfloor low-pressure pipe 152 and the like Occurrence of the stagnation phenomenon causes the oil circulation rate in the refrigeration cycle to decrease with time as shown in FIG. Here, the oil circulation rate (1.5% in the example of FIG. 4) necessary for ensuring the lubricity of the compressor 142 is set as a lower limit value, and the time for the oil circulation rate to fall to this lower limit value is measured in advance to operate. The upper limit of the predetermined time tx of the interval. The upper limit of the predetermined time tx obtained by such a method is 120 minutes.

  On the other hand, if the predetermined time tx of the operation interval is shortened, the electromagnetic clutch 141 is frequently engaged and the durability of the electromagnetic clutch 141 is reduced. Therefore, from the viewpoint of ensuring the durability of the electromagnetic clutch 141, the lower limit of the predetermined time tx of the operation interval is 30 minutes. As described above, the predetermined time tx of the operation interval needs to be set in a range of 30 minutes ≦ tx ≦ 120 minutes. In the present embodiment, tx is 30 minutes (1800 seconds), but can be set to a suitable value depending on the type of vehicle.

  Next, the clutch off time h will be described. As shown in FIG. 4, the blow-off temperature te of the front seat side evaporator 113 rises when the clutch is turned off with the forced on / off control of the electromagnetic clutch 141. Here, since the increase rate of the blowing temperature te increases as the air volume of the front seat side blower 144 increases, the temperature increase width Δte at which the occupant does not feel uncomfortable at the maximum air volume of the front seat side blower 144 is set to 5 ° C. When the clutch-off time h at which Δte ≦ 5 ° C. was obtained when the maximum air flow was clutch-off, h ≦ 10 seconds was obtained.

  On the other hand, when the clutch-off time h is shortened, the amount of increase in the low-pressure pressure during the clutch-off time h becomes small, the opening degree of the rear seat side expansion valve 124 at the time of subsequent clutch-on becomes insufficient, and the oil circulation rate is recovered. It becomes insufficient. Therefore, in order to secure the opening degree of the rear seat side expansion valve 124 when the clutch is on, the clutch off time h needs to be 3 seconds or more. From the above, it is necessary to set the clutch-off time h so as to be within the range of 3 seconds ≦ h ≦ 10 seconds.

  Next, the clutch on time H will be described. Increasing the clutch on time H is not preferable because the low pressure and the oil circulation rate within the clutch on time H are greatly decreased, and it is necessary to increase the number of intermittent times n. From such a viewpoint, H ≦ 20 seconds.

  Conversely, when the clutch-on time H is shortened, the amount of decrease in the blowing temperature te of the front-seat evaporator 113 due to the clutch-on is small, and the same result as increasing the clutch-off time h per time (evaporator blowing) Temperature rise width Δte> 5 ° C.), which causes passenger discomfort. For this reason, the clutch-on time H is set to 5 seconds or more. From the above, it is necessary to set the clutch-on time H so that it falls within the range of 5 seconds ≦ H ≦ 20 seconds.

  Finally, the number of intermittent times n will be described. As shown in FIG. 4, the oil circulation rate can be increased with an increase in the number of interruptions (clutch off times) n. From the viewpoint of ensuring the lubricity of the compressor 142, the recovery of the oil circulation rate is insufficient when the number of interruptions n = 1, and the number of interruptions n needs to be at least two or more.

  On the other hand, since the blowout temperature te of the front seat evaporator 113 increases as the number of intermittent times n increases, the number of intermittent times n is preferably 5 or less in order to suppress the discomfort of the passenger. That is, it is necessary to set the number of intermittent times n so that it falls within the range of 2 ≦ n ≦ 5.

  Based on the above concept and specific numerical examples, in this embodiment, in the low rotation mode (Nc ≦ 1100 rpm) mainly during idling, the stop time h is 10 seconds, the operation time H is 10 seconds, and the number of intermittent times n is It is set to 4 times. On the other hand, in the high rotation mode (Nc ≧ 1100 rpm) assuming traveling, the stop time h is set to 5 seconds, the operation time H is set to 10 seconds, and the intermittent number of times n is set to 2 times. That is, in the present embodiment, in the high rotation mode, the stop time h and the number of interruptions n of the compressor 142 are set to values smaller than those values in the low rotation mode.

  Next, a detailed operation in the forced intermittent control with the contents set as described above will be described with reference to FIG. As shown in FIG. 4, the oil circulation rate of the refrigeration cycle R decreases with the continuous operation of the compressor 142, but can be increased stepwise by forced on / off control of the compressor 142. This is because when the compressor operation is forcibly interrupted, the rear seat side low pressure varies, and when the compressor 142 is turned on, the rear seat side low pressure decreases so that the rear seat side expansion valve 124 is forced. This is because the valve is opened.

  More specifically, the opening operation of the rear seat side expansion valve 124 will be described. After the low pressure is increased and the temperature of the temperature sensing portion of the rear seat side expansion valve 124 is increased when the clutch is off, the compressor 142 is restarted. Since the low-pressure pressure is reduced by activation, a differential pressure in the valve opening direction is generated in the diaphragm portion of the rear seat side expansion valve 124, and the rear seat side expansion valve 124 can be forcibly opened. Thereby, since the refrigerant | coolant of the collective flow volume can be made to flow in into the rear seat side evaporator 123 through the rear seat side expansion valve 124, the lubricating oil collected in the underfloor low-pressure piping 152 by this refrigerant flow is made into the suction side of the compressor 142 Can be pushed back to.

  Further, at the time of high rotation, the degree of increase in the oil circulation rate when the clutch is turned on is larger than that at the time of low rotation. This is because the flow rate of the refrigerant flowing when the rear seat side expansion valve 124 is in the open state is higher at the time of high rotation than that at the time of low rotation. That is, since the oil return performance (the degree of increase in the oil circulation rate) is better at high revolutions than at low revolutions, the clutch off time h is shorter in the high revolution mode than in the low revolution mode, and the number of interruptions n Even if it is set to be small, the same increase in oil circulation rate is secured. In the present embodiment, the oil circulation rate that has decreased to 1.5% at both low and high rotations has increased to approximately 6% after the forced on / off control of the compressor 142.

  On the other hand, the front seat side blowing temperature te increases when the clutch is off and decreases when the clutch is on. Here, when the same intermittent control is performed at the time of high rotation as at the time of low rotation, normally, the variation in the blowing temperature te accompanying the intermittent control of the compressor 142 at the time of high rotation (= the blowing temperature fluctuation range Δte). Becomes larger. However, in this embodiment, since the clutch-off time h at the time of high rotation is short and the number of times of intermittent operation n is set small, the value of the blowing temperature fluctuation Δte after completion of intermittent control is low and low. It is almost the same value as time.

  In other words, in the present embodiment, during the forced on / off control of the compressor 142 at the time of high rotation, the blowout temperature fluctuation width Δte is suppressed within an allowable range (Δte <5 ° C.) while reliably increasing the oil circulation rate. it can. This makes it possible to avoid occupant discomfort due to the variation in the blowout temperature in the oil return control regardless of the rotation speed of the compressor 142.

  In the present embodiment, the predetermined value for distinguishing between the low rotation mode and the high rotation mode is 1100 rpm, but this value can be suitably changed in the range of 1000 to 1800 rpm. In general, by setting within this range, it is possible to classify the low rotation and the high rotation in which the blowing temperature fluctuation range Δte is greatly different.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. FIG. 5 is a flowchart illustrating oil return control executed by the control unit in the second embodiment. In FIG. 5, the same steps as those in the flowchart (FIG. 3) showing the first embodiment are denoted by the same reference numerals. The present embodiment is different from the first embodiment in that the control mode is appropriately selected according to the blower level of the conditioned air on the front seat side in addition to the rotational speed Nc of the compressor 142. In the said 1st Embodiment, although the time of the maximum air volume of the front seat side air blower 144 is assumed, the blowing temperature fluctuation | variation differs with the blower level (air volume) of the front seat air blower 144. FIG. In the present embodiment, focusing on the fact that the blower temperature fluctuation is smaller when the blower level is lower, more precise control is performed.

  First, as a premise, the ROM of the air conditioner ECU 160 stores six types of control modes associated with the respective rotational speeds and blower levels, as shown in FIG. In the low rotation first mode in which the blower level is set to a low setting in the low rotation range (Nc ≦ 1100 rpm) mainly during idling / congestion, the stop time of the compressor 142 at the time of oil return control h is set to 12 seconds, the operation time H is set to 10 seconds, and the number of interruptions n is set to 4 times. Further, in the low-rotation second mode that is the low rotation region (Nc ≦ 1100 rpm) and the blower level is set to M2 to Hi, the stop time h of the compressor 142 at the time of oil return control is 10 seconds. The operation time H is set to 10 seconds, and the number of interruptions n is set to 4 times.

  Further, in the middle rotation first mode in which the blower level is Lo to M1 in the middle rotation region (1100 <Nc <1800) mainly for urban / general road travel, the stop time of the compressor 142 at the time of oil return control h is set to 10 seconds, the operating time H is set to 10 seconds, and the number of interruptions n is set to 2 times. In the middle rotation second mode, which is also in the middle rotation region (1100 <Nc <1800) and the blower level is M2 to Hi, the stop time h of the compressor 142 during the oil return control is 7 seconds and the operation time. H is set to 10 seconds, and the number of interruptions n is set to 2.

  Further, in the high rotation first mode in which the blower level is Lo to M1 in the high rotation region (Nc ≧ 1800 rpm) mainly during high speed running, the stop time h of the compressor 142 at the time of oil return control is 10 seconds. The operation time H is set to 10 seconds, and the number of interruptions n is set to 1. Further, in the high rotation second mode that is also in the high rotation region (Nc ≧ 1800 rpm) and the blower level is M2 to Hi, the stop time h of the compressor 142 at the time of oil return control is 5 seconds, and the operation time H is The number of intermittents n is set to 10 seconds for 10 seconds. In any rotation region, in the second mode with a high blower level, the stop time h of the compressor 142 is set shorter than in the first mode with a low blower level.

  Hereinafter, a specific processing procedure of the present embodiment will be described with reference to a flowchart of FIG. As shown in FIG. 5, after step S130 described in the first embodiment, first, in step S140, it is determined whether or not the rotational speed Nc of the compressor 142 detected from the compressor rotational speed sensor 162 is 1100 rpm or less. . If the rotational speed Nc is 1100 rpm or less (step S140: YES), it is determined in step S141 whether the blower level is Lo to M1. When the blower level is any of Lo to M1 (step S141: YES), the low rotation first mode is set in step S142. On the other hand, if the blower level is not Lo to M1 (step S141: NO), that is, if the blower level is any of M2 to Hi, the low rotation second mode is set in step S143.

  If the rotation speed Nc of the compressor 142 is greater than 1100 rpm (step S140: NO), it is determined in step S151 whether the rotation speed Nc is smaller than 1800 rpm. If the rotational speed Nc is smaller than 1800 rpm (step S151: YES), that is, if the rotational speed Nc is in the range of 1100 rpm <Nc <1800 rpm, it is determined in step S152 whether the blower level is Lo to M1.

  When the blower level is any of Lo to M1 (step S152: YES), the medium rotation first mode is set in step S153. On the other hand, when the blower level is not Lo to M1 (step S152: NO), that is, when the blower level is any one of M2 to Hi, the medium rotation second mode is set in step S154.

  Furthermore, when the rotation speed Nc of the compressor 142 is 1800 rpm or more (step S151: NO), it is determined in step S161 whether the blower level is Lo to M1. If the blower level is any of Lo to M1 (step S161: YES), the high rotation first mode is set in step S162. On the other hand, when the blower level is not Lo to M1 (step S161: NO), that is, when the blower level is any of M2 to Hi, the high rotation second mode is set in step S163.

  After setting to each control mode, in step S170, forced on / off control of the compressor 142 is executed with the contents set in each mode. The subsequent processing is the same as in the first embodiment.

  According to the concept described in detail in the first embodiment, the clutch-off time h for forced on / off control is preferably 3 seconds ≦ h ≦ 10 seconds. However, in the first embodiment, it is assumed that the blower level is maximum. is doing. In this regard, in the present embodiment, as shown in FIG. 6, in the first mode at each rotational speed, the blower level is lower Lo to M1, so the clutch off time h can be set longer than 10 seconds. It is possible.

  According to the present embodiment, since the blower level is considered in addition to the rotational speed Nc of the compressor 142 in selecting the control mode, the clutch off time h when the blower level is lower can be set longer. it can. By setting the clutch off time h to be long, the increase range of the low pressure can be increased, and the oil circulation rate can be reliably increased accordingly.

  In addition, although the operation explanatory diagram in this embodiment is omitted, as in the case shown in FIG. 4 in the first embodiment, the oil circulation rate is about 6% after the forced intermittent control in any control mode. And the blowout temperature fluctuation range Δte can be set within 5 ° C.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. FIG. 7 is a flowchart illustrating oil return control executed by the control unit in the third embodiment. In FIG. 7, the same steps as those in the flowchart (FIG. 3) showing the first embodiment are given the same reference numerals. Hereinafter, the description will be given focusing on portions different from the first embodiment.

  As shown in FIG. 7, when the air conditioner is on (S110: YES), it is determined in step S111 whether or not the rotational speed Nc of the compressor 142 is smaller than 2000 rpm. When the rotation speed Nc is smaller than 2000 rpm (threshold) (step S111: YES), the low rotation timer t1 is counted in step S112. On the other hand, when the rotation speed Nc is 2000 rpm or more (step S111: NO), the high rotation timer t2 is counted in step S113.

  Next, in step S114, an oil circulation rate decrease value OCR_drop is calculated based on the following Equation 1.

(Equation 1)
OCR_drop = (2/3600) × t1 + (2/1800) × t2
Details of this equation will be described later. Next, in step S115, it is determined whether or not the oil circulation rate decrease value OCR_drop is equal to or greater than an allowable value 2 (specified value) predetermined by the system. When the oil circulation rate decrease value OCR_drop is 2 or more (step S115: YES), the process proceeds to step S140. On the other hand, when the oil circulation rate decrease value OCR_drop does not exceed 2 (step S115: NO), the process returns to step S110.

  Next, a method for deriving Equation 1 will be described. In the present embodiment, as an example, the air conditioner in the case where the oil circulation rate at the initial stage of startup is 6% and the allowable oil circulation rate is 4%, that is, the allowable value of the oil circulation rate decrease value OCR_drop is 2 (%). Think of a system.

  FIG. 8 is a diagram showing the relationship between the front seat side independent operation time t and the oil circulation rate for each rotation speed. The oil circulation rate reduction value OCR_drop differs depending on the rotational speed Nc of the compressor 142. As shown in FIG. 8, when the time for the oil circulation rate to decrease from 6% to 4% is compared, when the rotational speed Nc of the compressor 142 is 3000 rpm, the rotational speed Nc is 1800 seconds. In the case of 2000 rpm, the time is doubled to 3600 seconds.

This means that the smaller the rotation speed Nc, the less oil is accumulated and the lowering rate of the oil circulation rate is smaller. Here, when the rotational speed Nc is less than 2000 rpm, it is assumed that the oil circulation rate is reduced as shown in a straight line in the case of 2000 rpm shown in FIG. 8, and when the rotational speed Nc is 2000 rpm or more, the rotational speed is approximately 3000 rpm shown in FIG. It is assumed that the oil circulation rate decreases as in the case of the straight line. If the continuous operation time of 0 <Nc <2000 rpm is t1, and the continuous operation time of Nc ≧ 2000 rpm is t2,
The oil circulation rate decrease value OCR_drop1 with respect to the continuous operation time t1 when the rotation speed Nc is 2000 rpm is
(Equation 2)
OCR_drop1 = (2/3600) × t1
Is required.

Further, the oil circulation rate decrease value OCR_drop2 with respect to the continuous operation time t2 when the rotation speed Nc is 3000 rpm is:
(Equation 3)
OCR_drop2 = (2/1800) × t2
Is required.

Therefore, the oil circulation rate lowering value OCR_drop as the entire system is calculated from Equations 2 and 3.
(Equation 4)
OCR_drop = OCR_drop1 + OCR_drop2
The above formula 1 is obtained from the formulas 2, 3, and 4.

  When the rotational speed Nc is small, the time until the oil circulation rate decreases by 2% is longer than when the rotational speed Nc is large, so the forced intermittent control is executed at the same frequency as when the compressor 142 is rotating at high speed. There is no need to do. In this regard, in the present embodiment, the oil circulation rate decrease value OCR_drop based on the rotational speed Nc is always calculated, and the forced intermittent control of the compressor 142 is performed only when the calculated value becomes 2 or more. Yes.

  Therefore, compared with the case where the interval for performing the forced intermittent control of the compressor 142 is fixed to tx (seconds) in advance, the interval for performing the forced intermittent control can be substantially extended when the compressor 142 is at a low speed. . Thereby, while being able to perform efficient control, durability of the compressor 142 (electromagnetic clutch 141) can be improved.

  In the present embodiment, the value (2000 rpm) of the rotation speed Nc that divides low rotation and high rotation corresponds to the “predetermined threshold value” of the present invention, and is set as the allowable value of the oil circulation rate decrease value OCR_drop. The value “2” corresponds to the “predetermined predetermined value” of the present invention, but these values can be appropriately changed depending on the vehicle type or the like.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG. FIG. 9 is a flowchart illustrating oil return control executed by the control unit in the fourth embodiment. The present embodiment performs substantially the same control as the third embodiment, and is similar in that the interval for performing the forced on / off control can be extended, but the processing arithmetic expression is different.

  In this embodiment, as shown in FIG. 9, after steps S112 and S113 described in the third embodiment, a conversion time tv is calculated in step S116 based on a conversion equation shown in the following equation 5.

(Equation 5)
tv = 1/2 × t1 + t2
This conversion formula will be described later. Next, in step S117, it is determined whether or not the conversion time tv is equal to or longer than tx. Here, tx is set to 1800 seconds. If the conversion time tv is equal to or longer than tx (step S117: YES), the process proceeds to step S140. On the other hand, when the conversion time tv does not exceed tx (step S117: NO), the process returns to step S110.

Next, Formula 5 will be described. The concept is the same as in the third embodiment. As shown in FIG. 8, when the rotational speed Nc is 2000 rpm, the oil circulation rate reduction rate OCR_dropR1 per second is
(Equation 6)
OCR_dropR1 = 2/3600
It is.

Further, when the rotational speed Nc is 3000 rpm, the oil circulation rate reduction rate OCR_dropR2 per unit second is:
(Equation 7)
OCR_dropR2 = 2/1800
It is.

As can be seen from Equations 6 and 7, the oil circulation rate reduction rate when the rotational speed Nc is 2000 rpm is ½ that when the rotational speed Nc is 3000 rpm. Therefore, when the elapsed time is converted in consideration of the difference in the oil circulation rate reduction rate, if the elapsed time t is 1800 seconds and the allowable oil circulation rate reduction value is 2, the rotation speed Nc is 2000 rpm. The constant for the time t1 is ½, and the constant for the operating time t2 when the rotation speed Nc is 3000 rpm is 1. Therefore, the conversion time tv1 when the rotation speed Nc is 2000 rpm is
(Equation 8)
tv1 = 1/2 × t1
It becomes.

Similarly, the conversion time tv2 when the rotation speed Nc is 3000 rpm is
(Equation 9)
tv2 = 1 × t2
It becomes.

  From the above, when the operating times t1 and t2 are converted in consideration of the oil circulation rate reduction rate at the respective rotation speeds, the above formula 5 is derived by adding the formula 8 and the formula 9. In the present embodiment, the conversion time based on the rotational speed Nc is always calculated, and the forced intermittent control of the compressor 142 is performed only when the calculated value is equal to or greater than tx.

  Therefore, as in the third embodiment, when the compressor 142 is rotating at a low speed, the interval for performing the forced on / off control can be substantially extended and the durability of the compressor 142 (electromagnetic clutch 141) is improved. be able to.

(Other embodiments)
In each of the above-described embodiments, two types of control modes, the low rotation mode and the high rotation mode, are employed depending on the rotation speed Nc. However, the control mode may be further subdivided to have three or more control modes. For example, when three control modes are set, the rotation speed Nc of the compressor 142 is divided into three stages of 0 <Nc ≦ 1100 rpm, 1100 rpm <Nc <1800 rpm, Nc ≧ 1800 rpm, and the clutch off time h is appropriately set. The clutch-on time H and the number of intermittent times n can be set. In this case, more precise control can be performed.

  In each of the above embodiments, it may be determined whether or not only the front seat air conditioning unit 110 is in the single operation state, and the timer is started only in the single operation to perform forced intermittent control. In this case, as shown in FIG. 10, it can implement by adding step S118 which judges whether it is independent operation between step S110 and step S120. Specifically, it is determined whether or not the continuous operation time of the rear seat side fan 122 is 20 seconds or longer. If the continuous operation time is 20 seconds or shorter, it can be determined that the operation is a single operation (single operation), and the time exceeds 20 seconds. If it is, it can be determined that the vehicle is in dual operation.

  In this way, the forced on / off control of the compressor 142 is performed only when the air conditioner is in the on state and the front seat air conditioning unit 110 is operating alone, so that compression during dual operation is unlikely to cause oil stagnation. Therefore, the durability of the electromagnetic clutch 141 can be improved and the control efficiency can be improved.

  In each of the above-described embodiments, it is assumed that the blowing position mode is the FACE mode or the B / L mode. However, it is determined whether the blowing position mode is the FACE mode or the B / L mode. In the case of determination, the forced on / off control in each of the above embodiments classified according to the rotation speed Nc may be performed. Or you may vary the content of forced intermittent control by the difference in blowing position mode. In this case, in the FACE mode or the B / L mode in which the influence of the blowout temperature fluctuation on the occupant is greater, the forced intermittent control according to the rotational speed Nc can be performed.

  In each of the above embodiments, the rotational speed Nc of the compressor 142 is obtained from the compressor rotational speed sensor 162, but may be calculated from the engine rotational speed Ne by a pulley ratio.

  The air conditioner ECU 160 in each of the above embodiments is premised on the one using a microcomputer, but may be one using a mechanical circuit such as a relay.

  In each of the above embodiments, the compressor 142 is a fixed capacity type, but may be configured as a variable capacity type compressor or an electric type compressor. In the case of the variable displacement type, the discharge amount of the compressor is changed between the minimum and maximum in place of the on / off operation of the electromagnetic clutch 141, and in the case of the electric type, the change is performed by the on / off operation of the motor. be able to.

  In each of the above-described embodiments, both the clutch-off time h and the number of intermittent operations n are different in the low rotation mode and the high rotation mode, but only one of them may be different. Since these parameters are correlated with each other, the clutch-off time h, the clutch-on time H, and the number of on / off times n can be appropriately changed within a suitable range as shown in the specific numerical examples above.

  In each of the above-described embodiments, after executing the intermittent interruption n = 1 only in the forced intermittent control of the compressor 142, it is determined whether the rotational speed Nc has changed beyond the boundary value of the predetermined value 1100 rpm, and the determination result is In response, the control mode may be set again. According to this, it is possible to appropriately cope with the case where the running speed (engine speed) changes significantly after the rotational speed Nc is determined in step S140 and the rotational speed Nc of the compressor 142 changes. .

It is a mimetic diagram showing the whole composition of the refrigeration cycle device for vehicles in a 1st embodiment of the present invention. It is a schematic block diagram which shows the electric control part in 1st Embodiment. It is a flowchart explaining the oil return control which a control part performs in 1st Embodiment. It is a time chart which shows the action | operation of a compressor, the oil circulation rate, and the blowing temperature in the forced intermittent control of a compressor. It is a flowchart explaining the oil return control which a control part performs in 2nd Embodiment. It is a figure explaining each control mode corresponding to the number of rotations of a compressor, and a blower level in a 2nd embodiment. It is a flowchart explaining the oil return control which a control part performs in 3rd Embodiment. It is a figure which shows the relationship between the front seat side independent operation time and oil circulation rate in each rotation speed. It is a flowchart explaining the oil return control which a control part performs in 4th Embodiment. It is a flowchart explaining the oil return control which a control part performs in other embodiment.

Explanation of symbols

110 Front seat side air conditioning unit 112 Front seat side blower (first blower)
113 Front seat evaporator (first evaporator)
114 Front seat side thermal expansion valve (first decompression means)
120 Rear seat side air conditioning unit 123 Rear seat side evaporator (second evaporator)
124 Rear seat side temperature type thermal expansion valve (second decompression means)
141 Electromagnetic clutch 142 Compressor 143 Condenser 160 Air conditioner ECU (storage means, selection means, control means, control start time adjustment means, oil circulation rate decrease value calculation means, oil circulation rate decrease value determination means, conversion time calculation means, conversion Time judgment means)

Claims (10)

A compressor (142) for compressing and discharging the refrigerant;
A condenser (143) for cooling and condensing the refrigerant discharged from the compressor (142);
First decompression means (114) for decompressing and expanding the refrigerant condensed in the condenser (143);
A first evaporator (113) which is mainly used and evaporates the refrigerant decompressed and expanded by the first decompression means (114);
Second decompression means (124) connected in parallel with the first decompression means (114) and decompressing and expanding the refrigerant condensed in the condenser (143);
A second evaporator (123) that is selectively used and is connected in parallel with the first evaporator (113) and evaporates the refrigerant decompressed and expanded by the second decompression means (124), Of the first and second decompression means (114, 124), at least the second decompression means (124) adjusts the degree of superheat of the outlet refrigerant of the second evaporator (123). In the refrigeration cycle apparatus formed as
Each of the stop time (h), the operation time (H), and the number of intermittent operations (n) of the compressor (142) in the forced intermittent control in which the compressor (142) is forcibly stopped and repeatedly operated. Storage means (160) for storing a plurality of control modes set according to the rotational speed (Nc) of the compressor (142) so that at least one of the parameters is different;
Among the plurality of control modes stored in the storage means (160), one of the control modes is changed to the compressor (142 when a predetermined time (tx) elapses after the compressor (142) is driven. ) Selection means (S140, S150, S160) for selection based on the number of rotations (Nc);
A refrigeration cycle apparatus comprising: control means (S170) that performs the forced intermittent control in the control mode selected by the selection means (S140, S150, S160).   The control mode when the rotational speed (Nc) of the compressor (142) is large when the predetermined time (tx) has elapsed is compared with the control mode when the rotational speed (Nc) is small. 2. The refrigeration cycle according to claim 1, wherein a value of at least one parameter of the stop time (h) of the compressor (142) and the number of intermittent times (n) of the compressor (142) is set to be small. apparatus.   The control mode includes a low rotation mode in which the rotation speed (Nc) of the compressor (142) is a predetermined value or less, and a high rotation mode in which the rotation speed (Nc) of the compressor (142) is higher than the predetermined value. The refrigeration cycle apparatus according to claim 1 or 2, wherein the predetermined value is set in a range of 1000 to 1800 rpm. A first blower (112) for blowing air to the first evaporator (113);
The plurality of control modes stored in the storage means (160) are associated with the rotational speed (Nc) of the compressor (142) and the blower level indicating the blower level of the first blower (112). Has been
The selection means (S140, S150, S160) is based on the rotational speed (Nc) of the compressor (142) and the blower level when a predetermined time (tx) has elapsed since the compressor (142) was driven. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein any one of the control modes is selected.   The control mode when the blower level is high when the predetermined time (tx) has elapsed is set to have a shorter stop time (h) of the compressor (142) than the control mode when the blower level is low. The refrigeration cycle apparatus according to claim 4, wherein the refrigeration cycle apparatus is provided. In the relationship between the time since the compressor (142) was driven and the rotation speed (Nc) of the compressor (142), the higher the ratio of the time when the rotation speed (Nc) is small, the lower the ratio Control start time adjusting means (S111 to S115, S116, S117) for adjusting so that the time until the forced intermittent control is started becomes longer than
The said control means (S170) performs the said forced intermittent control after progress of the time adjusted by the said control start time adjustment means (S111-S115, S116, S117). The refrigeration cycle apparatus as described in any one of them. The control start time adjusting means (S111 to S115, S116, S117)
A low rotation timer count value (t1) that is a timer measurement value when the rotation speed (Nc) of the compressor (142) is lower than a predetermined threshold, and the rotation speed (Nc) of the compressor (142). Based on the high rotation timer count value (t2) that is a timer measurement value when the threshold is equal to or greater than the threshold value, a decrease value of the oil circulation rate that is the ratio of the lubricating oil that is mixed in the refrigerant and circulates with the refrigerant is calculated. Oil circulation rate decrease value calculating means (S114) for calculating the oil circulation rate decrease value shown;
Oil circulation rate decrease value determining means (S115) for determining whether or not the oil circulation rate decrease value calculated by the oil circulation rate decrease value calculating means (S114) is equal to or greater than a predetermined value. The control means (S170) performs the forced intermittent control when the oil circulation rate lowering value determining means (S115) determines that the oil circulation rate lowering value is equal to or more than the specified value. The refrigeration cycle apparatus according to claim 6. The control start time adjusting means (S111 to S115, S116, S117)
A low rotation timer count value (t1) that is a timer measurement value when the rotation speed (Nc) of the compressor (142) is lower than a predetermined threshold, and the rotation speed (Nc) of the compressor (142). The high rotation timer count value (t2), which is a timer measurement value in the case of the threshold value or more, is multiplied by a constant corresponding to the rotation speed (Nc) of each of the compressors (142), and is calculated. Conversion time calculation means (S116) for calculating a conversion time by adding the values;
Conversion time determination means (S117) for determining whether or not the conversion time calculated by the conversion time calculation means (S116) is equal to or greater than a predetermined time (tx) set in advance, and the control means (S170) The refrigeration cycle according to claim 6, wherein the forced intermittent control is performed when the conversion time is determined by the conversion time determination means (S117) to be equal to or longer than the predetermined time (tx). apparatus.   The compressor (142) is a fixed capacity type compressor (142) having an electromagnetic clutch (141), and the control means (S170) performs the forced on / off operation by switching the electromagnetic clutch (141) on and off. Control is performed, The refrigerating-cycle apparatus as described in any one of Claims 1-8 characterized by the above-mentioned.   The front seat side air conditioning unit (110) for air conditioning the front seat side of the vehicle interior, the rear seat side air conditioning unit (120) for air conditioning the rear seat side of the vehicle interior, and any one of claims 1 to 9. The first evaporator (113) is disposed in the front seat air conditioning unit (110), and the second evaporator (123) is disposed in the rear seat air conditioning unit (120). A vehicle air conditioner characterized by being arranged.

Images