JP2014061789A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle enabled to increase and adjust capacities on the inside air side and outside air side of an inside/outside air two-layer air conditioning unit.SOLUTION: An air conditioner for a vehicle includes: a refrigeration cycle device including a compressor (22), an indoor condenser (12), diaphragms (26a, 26b, and 27), an outdoor heat exchanger (24), and an indoor evaporator (11); and an inside/outside air two-layer air conditioning unit (1). Inside air-side and outside air-side blowout temperatures of the inside/outside air two-layer air conditioning unit (1) are controlled to rise so that the difference between both the temperatures enters an allowed range by making a variation quantity of each time of control over an inside air-side air mixing door (16b) larger than a variation quantity of each time of control over an outside air-side air mixing door (16a) after the rotating speed (Nc) of the compressor (22) reaches a maximum rotating speed (Ncmax).

Description

  The present invention relates to an air conditioner for a vehicle using an indoor heat exchanger (condenser) instead of or in addition to a heater core in an inside / outside air two-layer air conditioning unit in which a flow path on the inside air side and the outside air side are separated.

  When heating with a vehicle air conditioner, air inside the vehicle interior (inside air) is sucked, heated with a heater core, and then blown out again into the vehicle interior. May become cloudy. For this reason, an internal / external air two-layer air conditioning unit in which the flow paths on the inside air side and the outside air side are separated as seen in Patent Document 1 and the like, aiming at both ventilation and removal of fog in the vehicle interior and ensuring a comfortable temperature. An air conditioning unit is also referred to as HVAC). In other words, in order to introduce outside air with low humidity and use it for defogging, it flows from the defroster outlet (also referred to as “DEF outlet”) and the face outlet (also referred to as “FACE outlet”) to the upper layer of the vehicle interior. In the lower layer (foot) of the room, relatively high temperature inside air is circulated from a foot outlet (also referred to as “FOOT outlet”) to ensure heating performance.

  In particular, the difference between the inside and outside air temperatures increases as the outside air temperature decreases. For example, if the outside air is 0 ° C., the temperature difference is about 25 ° C., but if the outside air is −20 ° C., the temperature difference spreads to 45 ° C. As described above, when the outside air temperature of the inside / outside air two-layer air conditioning unit is lowered and the intake temperature on the outside air side becomes low and a large difference occurs between the inside air side and the outside air side, the conventional art disclosed in Patent Document 1 or the like. In the technology, this state can be avoided by increasing the temperature and flow rate of the engine cooling water and controlling the air flow rate through the heater core.

  However, in a vehicle air conditioner of an electric vehicle (EV) without an engine that is a heating heat source or a hybrid vehicle (HV, PHV) in which engine heat is insufficient depending on operating conditions, the water temperature may not be increased. There was a problem that the temperature difference between the inside and outside air could not be controlled while maintaining the capacity. If the temperature difference between the inside and outside air cannot be controlled, a temperature difference will occur in the blowout to the face and legs, which will cause discomfort. This temperature difference between the upper and lower sides is generally considered to be uncomfortable at about 10 ° C., and when the temperature difference between the upper and lower sides is reversed, it leads to further discomfort.

JP 2000-016050 A

  In view of the above-described problems, the present invention provides a vehicle air conditioner capable of increasing and adjusting the capacity of the inside air side and the outside air side by combining an inside / outside air two-layer air conditioning unit and a heat pump.

  In order to solve the above-mentioned problems, the invention of claim 1 includes a compressor (22), an indoor condenser (12), a throttle (26a, 26b, 27), an outdoor heat exchanger (24), and an indoor evaporator. (11) at least a refrigeration cycle apparatus, and an inside / outside air two-layer air conditioning unit (1) separated into two layers of an outside air side passage and an inside air side passage, the blower (7), the indoor condenser (12 ) And the indoor evaporator (11) is disposed across the outside air side passage and the inside air side passage, and the indoor condenser (12) is provided in each of the outside air side passage and the inside air side passage. An inside / outside air two-layer air conditioning unit (1) having an outside air side and an inside air side air mix door (16a, 16b) capable of adjusting an air volume ratio between an air volume to be passed and an air volume to be passed through the bypass passages (35a, 35b). For vehicle air conditioners Then, after the rotation speed (Nc) of the compressor (22) reaches the maximum rotation speed (Ncmax), the amount of fluctuation per control of the inside air-side air mix door (16b) is expressed as the outside air-side air mix door ( 16a) is set to be larger than the amount of fluctuation per control, and the inside air / outside air blowing temperature of the inside / outside air two-layer air conditioning unit (1) is increased while keeping the temperature difference within an allowable temperature. It is controlled.

  In addition, the code | symbol attached | subjected above is an example which shows a corresponding relationship with the specific embodiment as described in embodiment mentioned later.

It is a system configuration figure of a 1st embodiment of the present invention. It is explanatory drawing of the air mix door (A / M door) control of 1st Embodiment of this invention. It is a Mollier diagram of heating operation mode of a 1st embodiment of the present invention. It is a Mollier diagram of the air_conditionaing | cooling operation mode of 1st Embodiment of this invention, and a dehumidification heating operation mode. It is explanatory drawing of the air mix door (A / M door) control of 1st Embodiment of this invention. It is a Mollier diagram of heating operation mode of a 1st embodiment of the present invention. It is a characteristic view which shows the relationship between the A / M door and blowing temperature of an inside / outside air two-layer air conditioning unit. It is a graph which shows the simultaneous control experiment result of the internal / external air A / M door of the internal / external air two-layer air conditioning unit of 1st Embodiment of this invention. It is a figure which shows the relationship of the inside / outside air A / M door opening degree in the control experiment result of FIG. It is an example of the control flowchart of 1st Embodiment of this invention. It is a flowchart of inside / outside air A / M door opening degree control of 1st Embodiment of this invention. It is a system configuration figure of a 2nd embodiment of the present invention. It is a Mollier diagram of the heating operation mode of the second embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. About each embodiment, the same code | symbol is attached | subjected to the part of the same structure, and the description is abbreviate | omitted.

  The present invention is mainly for the inside / outside air two-layer air conditioning unit in the inside / outside air two-layer mode among the inside air mode, the outside air mode, and the inside / outside air two layer mode, and the outside air is heated at a low temperature (eg, about −20 ° C.) The present invention is preferably applied to the operation mode, and is particularly effective when the heating capacity is insufficient even when the rotation speed Nc of the compressor reaches the maximum rotation speed Ncmax. The present invention increases the capacity by applying air mix door (A / M door) high pressure control to the inside / outside air two-layer air conditioning unit. The A / M door high-pressure control is control for increasing the heating capacity by changing the opening of the A / M door to reduce the amount of air passing through the indoor condenser, and will be described in detail later.

  Here, referring to FIG. 2, the opening degree of the A / M door is expressed as a ratio (%) between the passing air volume (G2) of the indoor condenser 12 and the passing air volume (G1) of the bypass passage. When fully closed and the total air volume passes through the indoor condenser 12 (G1 = 0) is 100%, and when the indoor condenser 12 is fully closed (G2 = 0) and the total air volume passes through the bypass passage Is 0%. The A / M door may be a sliding type or a rotating type, but for control purposes, the characteristic is converted into an air volume ratio. The opening of the A / M door will be described below as indicating the air volume ratio (%). Therefore, the opening degree of 50% is assumed to be when G1 = G2. Although the above description has been made on the outside air side, the same applies to the inside air side.

(First embodiment)
Before describing the A / M door high pressure control in detail, first, the overall configuration of the vehicle air conditioner according to the first embodiment of the present invention will be described with reference to FIG. The present embodiment is applied to a vehicle air conditioner, and includes a heat pump cycle 10 and an indoor air conditioning unit 1 that blows conditioned air into the vehicle interior. In the present embodiment, the indoor air conditioning unit (HVAC) 1 is an inside / outside air two-layer air conditioning unit.

  The indoor air conditioning unit 1 is disposed inside the foremost part of the vehicle interior. The indoor air-conditioning unit 1 has an air-conditioning case 1 ′ that forms an air passage for blown air that is blown into the vehicle interior. The air passage accommodates the blower 7, the indoor condenser 12, the indoor evaporator 11, and the like. On the most upstream side of the air flow in the air-conditioning case 1 ′, an inside / outside air switching device 33 that switches and introduces vehicle interior air (REC: inside air) and outside air (FRS) (intake air mode, inside air mode, outside air mode, inside / outside air 2) Layer mode is possible). On the downstream side of the air flow of the inside / outside air switching device 33, a blower 7 for blowing the air sucked through the inside / outside air switching device 33 is arranged and rotated by a control voltage output from the air conditioning control device (control ECU) 40. The number (air flow rate) is controlled. The blower 7 may be configured so that the amount of blown air can be independently controlled on the outside air side and the inside air side.

  The air passage is divided into two layers, an outside air passage (right side in FIG. 1) and an inside air passage (left side in FIG. 1). The outside air passage is connected to the defroster outlet 37a and the face outlet 37b, and the inside air passage is connected to the foot outlet 37c. The inside / outside air switching device 33 can switch to the inside air mode, the outside air mode, and the inside / outside air two-layer mode. The inside / outside air two-layer air conditioning unit is not limited to the embodiment shown in FIG. 1, and the present embodiment can be applied to a known inside / outside air two-layer air conditioning unit.

  On the downstream side of the air flow of the blower 7, the indoor evaporator 11 and the indoor condenser 12 are arranged in the order of the indoor evaporator 11 and the indoor condenser 12 with respect to the flow direction of the blown air. In the casing 1 ′, a bypass passage 35 (outside air side 35 a and inside air side 35 b) through which the blown air that has passed through the indoor evaporator 11 bypasses the indoor condenser 12 is provided. An air mix door (A / M door) 16 (outside air side 16a, inside air side 16b) is arranged on the downstream side of the air flow and on the upstream side of the air flow of the indoor condenser 12. The air mix door 16 adjusts the air volume ratio between the air volume that passes through the indoor condenser 12 and the air volume that passes through the bypass passage 35 in the blown air after passing through the indoor evaporator 11. This is a flow rate adjusting means for adjusting the flow rate (air volume) of the blown air flowing into the vessel 12, and also functions as a temperature adjusting means in the merging space 36 (outside air side 36a, inside air side 36b).

  On the downstream side of the air flow of the indoor condenser 12 and the bypass passage 35, the blown air heated by exchanging heat with the refrigerant in the indoor condenser 12 and the blown air not heated through the bypass passage 35 join together. A merge space 36 is provided. At the most downstream portion of the air flow of the casing 1 ′, a defroster outlet 37 a that blows conditioned air toward the inner surface of the front window glass of the vehicle, a face outlet 37 b that blows conditioned air toward the upper body of the passenger in the vehicle interior, A foot outlet 37c that blows air-conditioned air toward the feet is provided.

  The air mix door 16 adjusts the temperature of the blown air in the merging space 36 by adjusting the respective air volume ratios of the air volume that passes through the indoor condenser 12 and the air volume that passes through the bypass passage. A defroster door 38a, a face door 38b, and a foot door 38c for adjusting the opening area are disposed in the defroster outlet 37a, the face outlet 37b, and the foot outlet 37c, respectively. These doors are driven by a servo motor (not shown) whose operation is controlled by a control signal output from the air-conditioning control device 40, and in the vehicle interior via ducts that respectively form air passages on the downstream side thereof. It connects with each provided blowing opening. The compressor 22 is driven via the inverter 30 with electric power from the battery 31. In the case of normal auto air-conditioner control, the target blowout temperature TAO is determined by the vehicle interior set temperature Tset, the vehicle interior temperature (internal air temperature) Tr detected by the internal air sensor, the external air temperature Tam detected by the external air sensor, and the solar radiation sensor. It is calculated using the detected solar radiation amount Ts. Reference numeral 41 denotes these sensors and a sensor group such as the pressure sensor 41a, the temperature sensor 41b, and the temperature sensors 42a and 42b in FIG. The temperature sensors 42a and 42b detect the blowing temperature.

  The blow-off mode is a face mode in which the face blow-out opening 37b is fully opened and air is blown out from the face blow-out opening toward the upper body of the passenger in the vehicle interior. There are a bi-level mode in which air is blown toward the upper body and feet, a foot mode in which the foot blowing port 37c is fully opened and the defroster blowing port 37a is opened by a small opening, and air is mainly blown from the foot blowing port.

  Next, the heat pump cycle (refrigeration cycle apparatus) 10 of this embodiment will be described. As shown in FIG. 1, the heat pump cycle 10 includes a compressor 22, an indoor condenser 12, an outdoor heat exchanger 24, and an indoor evaporator 11, and includes a first throttle 26a, a second throttle 26b, a third throttle 27, The liquid separator 50 and the accumulator 25 are inserted into the refrigerant circuit as shown in FIG. Reference numerals 29, 23, and 28 denote an intermediate pressure side shut valve, a bypass valve, and a shut valve, respectively. The operation of these shut valves is controlled by a control signal output from the air conditioning controller 40.

  The compressor 22 is a two-stage booster type electric compressor composed of two compression mechanisms, a low-stage compression mechanism and a high-stage compression mechanism. The compressor 22 includes a suction port 22b that sucks into the low-stage compression mechanism from the outside, an intermediate-pressure port 22c that flows in the intermediate-pressure refrigerant and merges with the refrigerant in the compression process from low pressure to high pressure, and the high-stage compression mechanism. A discharge port 22a is provided for discharging from the discharge port. Various types of compression mechanisms such as a scroll type compression mechanism, a vane type compression mechanism, and a rolling piston type compression mechanism can be employed. Two compressors may be connected in series. The present invention can be applied even in a single-stage compression cycle as will be described later.

  The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port 22 a of the compressor 22. The indoor condenser 12 is disposed in the air conditioning case 1 ′ of the indoor air conditioning unit 1, functions as a radiator, and heats the blown air that has passed through the indoor evaporator 11. On the refrigerant outlet side of the indoor condenser 12, an inlet of a first throttle 26a (electric expansion valve with a fully opened function, fully opened in the cooling operation mode) that reduces the high-pressure refrigerant flowing out of the indoor condenser 12 until it becomes an intermediate pressure refrigerant. The side is connected. The first diaphragm 26a is a variable diaphragm mechanism. On the outlet side of the first throttle 26a, the refrigerant of the gas-liquid separator 50 as gas-liquid separation means that separates the gas-liquid of the intermediate pressure refrigerant that has flowed out of the indoor condenser 12 and has been depressurized by the first throttle 26a. An inflow port 50a is connected. The gas-liquid separator 50 includes a refrigerant inflow port 50a through which the intermediate pressure refrigerant flows, a gas phase refrigerant outflow port 50c through which the separated gas phase refrigerant flows out, and a liquid phase refrigerant outflow through which the separated liquid phase refrigerant flows out. It has a port 50b.

  The internal volume of the gas-liquid separator 50 according to the present embodiment is calculated based on the amount of refrigerant necessary for the cycle to exert its maximum capacity from the amount of refrigerant enclosed when the amount of refrigerant enclosed in the cycle is converted into the liquid phase. It is set smaller than the surplus refrigerant volume obtained by subtracting the required maximum refrigerant volume when converted to. For this reason, the internal volume of the gas-liquid separator 50 according to the present embodiment is such a volume that the surplus refrigerant cannot be substantially accumulated even if a load fluctuation occurs in the cycle and the refrigerant circulation flow rate circulating in the cycle fluctuates. It has become. As shown in the enlarged view of FIG. 1, the refrigerant flowing in from the refrigerant inflow port 50a swirls along the cylindrical inner wall surface, and the gas-liquid of the refrigerant is separated by the action of centrifugal force generated by this swirling flow. . The separated liquid phase refrigerant falls downward by the action of gravity and flows out from the liquid phase refrigerant outflow port 50b, and the separated gas phase refrigerant flows out from the gas phase refrigerant outflow port 50c.

  As shown in FIG. 1, the intermediate pressure port 22 c of the compressor 22 is connected to the gas-phase refrigerant outlet port 50 c of the gas-liquid separator 50 via the intermediate pressure refrigerant passage 15. An intermediate pressure side shut valve 29 is disposed in the intermediate pressure refrigerant passage 15. The intermediate pressure side shut valve 29 is an electromagnetic valve that opens and closes the intermediate pressure refrigerant passage 15. The intermediate pressure side shut valve 29 is a check valve that only allows the refrigerant to flow from the gas phase refrigerant outlet of the gas-liquid separator 50 to the intermediate pressure port 22 c side of the compressor 22 when the intermediate pressure refrigerant passage 15 is opened. It has the function of. The intermediate pressure side shut valve 29 functions to switch the cycle configuration (refrigerant flow path) by opening and closing the intermediate pressure refrigerant passage 15.

  The liquid-phase refrigerant outflow port 50b of the gas-liquid separator 50 is connected to the inlet side of the second throttle 26b for reducing the pressure of the liquid-phase refrigerant separated by the gas-liquid separator 50 until it becomes a low-pressure refrigerant. Is connected to the refrigerant inlet side of the outdoor heat exchanger 24. As the second diaphragm 26b, a nozzle or orifice with a fixed diaphragm opening can be employed. Of course, the second diaphragm 26b may be a variable diaphragm.

  In a fixed throttle in which the throttle passage area is suddenly reduced or expanded rapidly, the flow rate of the refrigerant passing through the second throttle 26b and the second throttle 26b in accordance with the change in the pressure difference between the upstream side and the downstream side (differential pressure between the inlet and outlet). The dryness of the upstream refrigerant can be self-adjusted (balanced). When the pressure difference is relatively large, a balance is made so that the dryness of the refrigerant on the upstream side of the fixed throttle increases as the necessary circulating refrigerant flow rate that needs to circulate the cycle decreases. On the other hand, when the pressure difference is relatively small, it is balanced so that the dryness of the fixed throttle upstream side refrigerant decreases as the required circulating refrigerant flow rate increases. However, if the degree of dryness of the refrigerant upstream of the second throttle 26b increases, the amount of heat absorbed by the outdoor heat exchanger 24 when the outdoor heat exchanger 24 functions as an evaporator that exerts an endothermic effect on the refrigerant. The (refrigeration capacity) decreases and the coefficient of performance (COP) of the cycle deteriorates.

  Therefore, even if the required circulating refrigerant flow rate changes due to cycle load fluctuations in the heating operation mode, the second throttle 26b in which the degree of dryness of the refrigerant on the upstream side of the second throttle 26b is 0.1 or less is adopted to reduce the COP. Suppressed. That is, in the second throttle 26b of the present embodiment, even if the refrigerant circulation flow rate and the differential pressure between the inlet and outlet of the second throttle 26b change within a range assumed when a load change occurs in the heat pump cycle 10, the second throttle 26b The dryness of the refrigerant on the upstream side of the throttle 26b is adjusted to 0.1 or less.

  The liquid-phase refrigerant outflow port 50b of the gas-liquid separator 50 is used for bypassing the second throttle that guides the liquid-phase refrigerant separated by the gas-liquid separator 50 to the outdoor heat exchanger 24 side by bypassing the second throttle 26b. A passage 18 is connected. A bypass valve 23 that opens and closes the second throttle bypass passage 18 is disposed in the second throttle bypass passage 18. The basic configuration of the bypass valve 23 is the same as that of the intermediate pressure side shut valve 29, and is an electromagnetic valve whose opening / closing operation is controlled by a control voltage output from the air conditioning control device 40. The refrigerant flowing out of the indoor condenser 12 flows into the outdoor heat exchanger 24 via the second throttle bypass passage 18 side when the bypass valve 23 is open, and when the bypass valve 23 is closed. Flows into the outdoor heat exchanger 24 through the second throttle 26b. The bypass valve 23 can switch the refrigerant flow path of the heat pump cycle 10.

  The outdoor heat exchanger 24 functions as an evaporator that evaporates low-pressure refrigerant and exerts an endothermic effect in the heating operation mode, and functions as a radiator that radiates high-pressure refrigerant in the cooling operation mode and the like. It is. The refrigerant inlet side of the third throttle 27 is connected to the refrigerant outlet side of the outdoor heat exchanger 24. The third throttle 27 is for depressurizing the refrigerant that flows out of the outdoor heat exchanger 24 and flows into the indoor evaporator 11 in the cooling operation mode or the like. The operation of the third diaphragm 27 is also controlled by a control signal output from the air conditioning controller 40.

  The refrigerant inlet side of the indoor evaporator 11 is connected to the outlet side of the third throttle 27. The indoor evaporator 11 is arranged in the air conditioning case 1 ′ of the indoor air conditioning unit 1 on the upstream side of the blower air flow of the indoor condenser 12, and circulates through the interior in the dehumidifying / heating operation mode or the like in the cooling operation mode. It is an evaporator which cools blowing air by evaporating and exhibiting an endothermic effect. The outlet side of the indoor evaporator 11 is connected to the inlet side of the accumulator 25. A suction port 22 b of the compressor 22 is connected to the gas phase refrigerant outlet of the accumulator 25. On the refrigerant outlet side of the outdoor heat exchanger 24, there is an indoor evaporator bypass passage 19 that guides the refrigerant flowing out of the outdoor heat exchanger 24 to the inlet side of the accumulator 25 by bypassing the third throttle 27 and the indoor evaporator 11. It is connected.

  A shut valve 28 for opening and closing the indoor evaporator bypass passage 19 is disposed in the indoor evaporator bypass passage 19. The basic configuration of the shut valve 28 is the same as that of the bypass valve 23, and its opening / closing operation is controlled by a control voltage output from the air conditioning control device 40. The refrigerant flowing out of the outdoor heat exchanger 24 flows into the accumulator 25 through the expansion valve bypass passage 25 when the shut valve 28 is open. At this time, the opening degree of the third diaphragm 27 may be fully closed. When the shut valve 28 is closed, it flows into the indoor evaporator 11 through the third throttle 27. The shut valve 28 switches the refrigerant flow path of the heat pump cycle 10.

  The vehicle air conditioner of FIG. 1 can perform a heating operation mode, a cooling operation mode, and a dehumidifying heating operation mode. Here, the heating operation mode relevant in this embodiment is demonstrated easily. The flow of the refrigerant in the heating operation mode is indicated by an arrow in FIG. That is, the first throttle 26a functions as a pressure reducing expansion valve, the third throttle 27 is fully closed, the intermediate pressure side shut valve is opened, the bypass valve 23 is closed, and the shut valve 28 is opened. FIG. 3 schematically shows the behavior in the Mollier diagram at this time. The compressor 22 is injected with an intermediate pressure from the intermediate pressure port 22c with an intermediate pressure (note that although the compression process is schematically shown as a straight line, a step is originally generated).

  In the refrigeration cycle of FIG. 1 of the present embodiment, the cooling operation mode can be set. In this cooling operation mode (in the Mollier line, the uppermost stage in FIG. 4), the first throttle 26a is fully opened, the third throttle 27 is functioned as a pressure reducing expansion valve, the intermediate pressure side shut valve is closed, and the bypass valve 23 is opened. The shut valve 28 is closed. At this time, the air mix doors 16a and 16b close the passage to the indoor condenser 12 and have an opening degree of 0%. The dehumidifying and heating operation mode is the same refrigeration cycle as the cooling operation mode, and the first dehumidifying and heating operation mode in which the opening degree of the air mix doors 16a and 16b is 0% or more (in the Mollier line, FIG. (Top row) can be set.

  In addition, the 2nd-4th dehumidification heating operation mode can be set. As the second dehumidifying and heating operation mode, the first throttle 26a is set to the throttled state, and the throttle opening degree of the third throttle 27 is set to the throttled state increased from the first dehumidifying and heating operating mode (two steps from the top in FIG. 4). Change as shown in the Mollier diagram of the eye). As the third dehumidifying and heating operation mode, the throttle opening of the first throttle 26a is set to a throttled state that is smaller than that of the second dehumidifying and heating operation mode, and the throttle opening of the third throttle 27 is set to the second dehumidifying and heating operation mode. (The change as shown in the Mollier diagram in the third row from the top in FIG. 4). In the fourth dehumidifying and heating operation mode, the throttle opening of the first throttle 26a is set to a throttled state that is smaller than that of the third dehumidifying and heating operating mode, and the throttle opening of the third throttle 27 is set to a fully open state (FIG. 4), as shown in the Mollier diagram in the lowermost row.

(Air mix door high pressure control)
The air mix door (A / M door) high-pressure control is a heating operation mode in which the outside air is at a low temperature (for example, about −10 ° C. to −20 ° C.) in the inside / outside air two-layer mode of the inside / outside air two-layer air conditioning unit. Even when the rotation speed of the compressor reaches the maximum rotation speed Nmax, it is particularly effective when the heating capacity is insufficient. In the inside / outside air two-layer mode, the inside / outside air temperature difference increases as the outside air temperature decreases, and the required heating capacity increases. Generally, the heating capacity becomes severe under conditions where the outside air temperature is about −10 ° C. or less. This makes it difficult to deal with electric vehicles (EV). In such a case, if the air mix door (A / M door) high pressure control is applied, the capacity can be further increased.

With reference to FIGS. 3 and 5, it will be described whether the heating capacity can be increased by changing the opening of the A / M door to reduce the amount of air passing through the indoor condenser.
When the heater core and the inside / outside air two-layer air conditioning unit are combined as in the prior art, even if the amount of air passing through the heater core is reduced, there is no effect on the refrigeration cycle, so the heating capacity becomes smaller as the amount of air decreases. On the other hand, when the indoor condenser 12 and the inside / outside air two-layer air conditioning unit of the heat pump cycle as in the present embodiment are combined, the control is performed from the cycle C1 before the A / M door high pressure control shown in FIG. When the amount of air passing through the indoor condenser 12 is reduced so as to shift to the cycle C2, the high pressure of the cycle C2 increases, the power of the compressor 22 increases by ΔW, and a temperature difference from the air passing through the indoor condenser is taken. To balance. Thus, even if the rotation speed of the compressor reaches the maximum rotation speed Nmax, the heating capacity can be increased.

  FIG. 5 is an explanatory diagram showing that the final blowing temperature is increased by A / M door high-pressure control in an illustrative manner. In (2) of FIG. 5, when the opening degree of the A / M door is set to 50%, the high pressure is increased from 1.2 Mpa to 2.2 MPa, the enthalpy is increased, and the refrigerant temperature is increased in the Mollier diagram. ing. Thereby, the situation where the final blowing temperature is rising is illustrated. For the above explanation, the intermediate pressure is schematically described as being constant before and after the A / M door high-pressure control. However, in actual control, the high pressure increases as the passing air volume of the indoor condenser 12 decreases as shown in FIG. As the high pressure increases, the intermediate pressure also increases, and the injection flow rate to the compressor 22 at the intermediate pressure increases. For this reason, it has been confirmed by experiments that the work amount of the compressor 22 is increased and a larger heating capacity is obtained.

  As described above, the A / M door high pressure control is effective in obtaining a larger heating capacity. However, when the indoor condenser 12 of the heat pump cycle and the inside / outside air two-layer air conditioning unit are combined, Such a problem arises. For example, when a part of the air is bypassed by opening the A / M door on the inside air side, the total air volume passing through the indoor condenser 12 is reduced, so that the refrigerant temperature in the indoor condenser 12 is increased. As a result, the temperature difference between the passing air and the refrigerant increases, so that the heating capacity on the outside air side increases. However, on the inside air side, a part of the air is bypassed, so the amount of passing air in the indoor condenser 12 is reduced and the heating capacity is increased. May fall.

  That is, in the case of the inside / outside air two-layer air conditioning unit, since there are A / M doors in the inside air side flow path and the outside air side flow path respectively, when there is a temperature difference between the air in the inside air side flow path and the outside air side flow path, The influence on the blowing temperature (FOOT on the inside air side, FACE and DEF blowing temperatures on the outside air side) when each door is moved is different. FIG. 7 is a characteristic diagram showing the relationship between the A / M door and the blowout temperature of the inside / outside air two-layer air conditioning unit. The upper part of FIG. 7 is a characteristic diagram when only the outside air side A / M door is moved, and as the outside air side A / M door opening (100% → 0%) becomes smaller, the inside air side blowing temperature ( Experiments have shown that FOOT) rises and the temperature difference from the outside air blowing temperature (FACE, DEF) increases. As the outside air side A / M door opening degree becomes smaller, a very large temperature difference occurs in the blowout to the face (FACE, DEF) and legs (FOOT), giving unpleasant feeling.

  Further, the middle part of FIG. 7 is a characteristic diagram when only the inside air side A / M door is moved. As the inside air side A / M door opening degree (100% → 0%) becomes smaller, the outside air side blowout is performed. Experiments have shown that the temperature (FACE, DEF) rises and reverses to the blowout temperature (FOOT) on the inside air side. When such a difference in temperature between the upper and lower sides is reversed, the passenger feels uncomfortable feeling such as burning of the face.

  The present embodiment solves such a problem. As a result of earnest research, when the variation amount of the inside air side A / M door opening and the outside air side A / M door opening is changed independently, It has been found that the air discharge temperature difference does not increase and can be suppressed to a temperature difference within a predetermined allowable range (for example, 10 ° C. or the like). An example of such experimental results (outside air: about −20 ° C., inside air: normal cabin temperature) is the result of the control experiment shown in FIG. The control experiment result of FIG. 8 shows that the inside / outside air / outside air when the inside / outside air A / M door opening degree (inside air A / M door fluctuation amount: outside air A / M door fluctuation amount = 2: 1) is moved as shown in FIG. The blowing temperature and the discharge pressure (indoor condenser pressure) are shown.

In the example of the control experiment result in FIG. 8, the blowout temperature on the inside air side and the blowout temperature on the outside air side monotonously increase as the outside air side A / M door opening decreases while maintaining a predetermined temperature difference. At this time, the discharge pressure (high-pressure side refrigerant pressure Pd) of the compressor 22 also increases monotonically as the outside air-side A / M door opening decreases. If the vicinity of 100% of the outside air side A / M door opening is excluded, the fluctuation amount per control of the inside air side A / M door opening is changed to the fluctuation per control of the outside air side A / M door opening. It can be seen that the discharge pressure increases when the door opening is decreased by double the amount.
Here, the fluctuation amount per control refers to the amount moved by one control. For example, “one control” indicates one control cycle (τ) seen in step S13 of the flowchart of FIG.

  Therefore, if the high-pressure side refrigerant pressure Pd detected by the pressure sensor 41a is smaller than the target high pressure TP, the door pressure approaches the target high pressure TP when the respective door openings are decreased at a constant ratio. At this time, the blowout temperature on the inside air side and the blowout temperature on the outside air side increase as the inside / outside air side A / M door opening degree decreases while maintaining a predetermined temperature difference. In the present embodiment, even if the rotation speed Nc of the compressor reaches the maximum rotation speed Ncmax, the heating capacity is insufficient, so both the blowout temperature on the inside air side and the blowout temperature on the outside air side maintain a predetermined temperature difference. A sufficient effect can be obtained by increasing the control. Here, the target temperature is not determined independently on the inside air side and the outside air side, but the target temperature may be determined by, for example, FOOT so that the DEF falls within the allowable temperature difference.

  The amount of fluctuation per unit time of the inside air side A / M door opening is reduced within a certain ratio or within a predetermined ratio with respect to the fluctuation amount per unit time of the outside air A / M door opening, and a predetermined allowable range The respective blowout temperatures are raised while keeping the temperature difference inside (for example, 10 ° C.). Thereby, in the blowout to the face and legs, a very large temperature difference or reverse occurs, and there is no discomfort, even if the rotation speed Nc of the compressor reaches the maximum rotation speed Ncmax, The heating capacity can be increased.

  In the normal accumulator cycle, the supercooling degree of the high pressure after the outflow of the indoor condenser is controlled so as to become the target supercooling degree so that the coefficient of performance (COP) is maximized. This control is performed when the valve opening 26a is within the adjustable range. In addition, even if the rotation speed Nc of the compressor reaches the maximum rotation speed Ncmax, when the valve opening degree of the first throttle 26a is within the adjustable range, the valve opening degree of the first throttle 26a is increased to increase the first throttle. The dryness of the refrigerant after passing through 26a may be increased (the same behavior as in FIG. 6 on the Mollier diagram), and the intermediate pressure gas injection amount of the compressor 22 may be increased (this is called dryness control). In the present embodiment, when the valve opening of the first throttle 26a is within the adjustable range, the dryness control may be performed after the rotation speed Nc of the compressor 22 reaches the maximum rotation speed Ncmax. Of course, you may control dryness before reaching.

An example of a control flowchart of the present embodiment will be described with reference to FIG. 10, but the control of the present embodiment is not limited to this.
In the main routine of FIG. 10, in step S1, initialization such as initialization of flags, timers, and initial positions of various actuators is performed, and the process proceeds to step S2. In step S2, the set temperature Tset in the vehicle interior set by the vehicle interior temperature setting switch, the operation signal of the operation panel such as the operation mode selected by the mode selection switch, etc. are read, and the process proceeds to step S3. In step S3, the vehicle environmental state signal used for air conditioning control, that is, the detection signal of the sensor group 41 for air conditioning control is read, and the process proceeds to step S4. In step S4, the target blowing temperature (target temperature) TAO of the blown air blown out from the various outlets into the vehicle interior is calculated, and the process proceeds to step S5.

  Specifically, in step S4, the target blowout temperature TAO of the present embodiment includes a vehicle interior set temperature Tset, a vehicle interior temperature (internal air temperature) Tr detected by an internal air sensor, an external air temperature Tam detected by an external air sensor, It is calculated using the solar radiation amount Ts detected by the solar radiation sensor. In step S5, with reference to the control map previously stored in the air-conditioning control device 40, the air volume of the blower 32 (specifically, the blower motor voltage applied to the electric motor) is determined, and the process proceeds to step S6. In step S6, the suction low mode (inside air mode, outside air mode, inside / outside air two-layer mode), that is, the switching state of the inside / outside air switching device 33 is determined, and the process proceeds to step S7.

  In step S7, the operation mode, that is, the cooling operation mode, the dehumidifying heating operation mode, and the heating operation mode are determined based on the operation signal of the mode selection switch on the operation panel, and the process proceeds to steps S8 to 10 respectively. Control processing (determination of throttle and on / off valves, target high pressure TPd, compressor rotation speed Nc, etc.) is executed, and in steps 8 and 9, the process proceeds to step S11. When the heating operation mode is selected, the process proceeds to step S10, the control process of the heating operation mode is executed, and then the A / M opening degree is determined in step S100, and the process proceeds to step S11. The subroutine for determining the A / M opening degree in step S100 is shown in FIG. 11 and will be described later.

  In step S11, based on TAO, the blow mode (foot mode, bi-level mode, face mode) is determined with reference to a control map stored in advance in the air conditioning control device 40. In step S12, a control signal and a control voltage are output from the air conditioning control device 40 to various control target devices connected to the output side so that the control state determined in the above-described steps is obtained. In the subsequent step S13, the process waits for the control period τ, and returns to step S2 when it is determined that the control period τ has elapsed.

  The subroutine for determining the A / M opening degree in step S100 will be described with reference to FIG. In step S101, it is determined whether or not the rotational speed Nc of the compressor has reached the maximum rotational speed Ncmax. If not, the process proceeds to step S11 and returns to the main routine of FIG. If the compressor rotation speed Nc has reached the maximum rotation speed Ncmax in step S100, it is determined in step S102 whether or not the suction port mode is the inside / outside air two-layer mode. In step S104, the same value Z is set for the outside air side A / M door fluctuation amount A and the inside air side A / M door fluctuation amount B, and the process proceeds to step S105. In this case, the outside air side and inside air side A / M doors are moved by the same fluctuation amount. If the suction port mode is the inside / outside air two-layer mode in step S102, in step S103, a value X is set to the variation amount A of the outside air A / M door, and a value Y is set to the inside air A / M door variation amount B. And proceed to step S105. In this case, the values X and Y are set to different values. X and Y correspond to the amount of fluctuation per time τ, and Y> X. The case where Y = 2X is shown as an example in FIG.

  Next, in step S105, it is determined whether or not the current high-pressure side refrigerant pressure Pd is higher than the target high-pressure TPd determined in step S10. If it is determined in step S105 that the current high-pressure side refrigerant pressure Pd is equal to or higher than the target high-pressure TPd, the process proceeds to step 109, and if it is determined that the current high-pressure side refrigerant pressure Pd is less than the target high-pressure TPd, Proceeding to steps S106 and S107, it is determined whether or not the current outside air / inside air A / M door opening is larger than the minimum opening.

  If both of steps S106 and S107 are Yes, the outside air side A / M door opening is decreased by A and the inside air side A / M door opening is decreased by B in step S108. A and B are X and Y, respectively, in the case of the inside / outside air two-layer mode, and A and B are both set to Z in the other modes. In the case of No in step S105, in step 109, the outside air side A / M door opening is increased by A, and the inside air side A / M door opening is increased by B. Thereafter, the process returns to step S11 of the main routine.

(Second Embodiment)
In the second embodiment, the first embodiment is a refrigeration cycle apparatus that performs intermediate pressure injection. However, in the refrigeration cycle apparatus that does not perform this, air-conditioning control is performed on the inside / outside air two-layer air conditioning unit. The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port 22 of the compressor 22. The indoor condenser 12 is disposed in the air conditioning case 1 ′ of the indoor air conditioning unit 1, functions as a radiator, and heats the blown air that has passed through the indoor evaporator 11. The refrigerant outlet side of the indoor condenser 12 is connected to the inlet side of the first throttle 26a that depressurizes the high-pressure refrigerant flowing out of the indoor condenser 12 until it becomes an intermediate-pressure refrigerant. The first diaphragm 26a is a variable diaphragm mechanism. On the outlet side of the first throttle 26 a, the refrigerant that has flowed out of the indoor condenser 12 and has been depressurized by the first throttle 26 a flows into the outdoor heat exchanger 24. There is no second aperture. Other configurations of the refrigeration cycle apparatus are the same as those in the first embodiment.

  In the Mollier diagram (FIG. 13) of the heating operation mode of the second embodiment, when the cycle C1 before the A / M door high pressure control is shifted to the cycle C2 after the control, the amount of air passing through the indoor condenser 12 is reduced. The high pressure of the cycle C2 is increased and balanced so as to take a temperature difference from the indoor condenser passing air. Even if there is an amount of heat absorption ΔQ and power up ΔW of the compressor 22, the heating capacity cannot be increased as much as in the first embodiment. However, in the inside / outside air two-layer air conditioning unit, the amount of fluctuation per control of the inside air side A / M door opening is controlled at a constant ratio with respect to the amount of fluctuation per opening of the outside air A / M door opening control. Or it can reduce within the predetermined ratio, and can suppress the blowing temperature difference of inside / outside air to the temperature difference in a predetermined permissible range.

DESCRIPTION OF SYMBOLS 1 Inside / outside air 2 layer air conditioning unit 7 Blower 11 Indoor evaporator 12 Indoor condenser 16a, 16b Outside air side, inside air side air mix door 22 Compressor

Claims (7)

A refrigeration cycle apparatus comprising at least a compressor (22), an indoor condenser (12), a throttle (26a, 26b, 27), an outdoor heat exchanger (24), and an indoor evaporator (11);
An internal / external air two-layer air conditioning unit (1) separated into two layers of an external air side passage and an internal air side passage, wherein the blower (7), the indoor condenser (12), and the indoor evaporator (11) are The outdoor air passage and the inside air passage are arranged across the outside air passage and the inside air passage, and an air volume and a bypass passage (35a, 35b) through which the indoor condenser (12) is passed, respectively. In a vehicle air conditioner comprising: an outside air side and an inside air side air mix door (16a, 16b) having an outside air side and an inside air side air mix door (16a) capable of adjusting an air volume ratio with a passing air volume;
After the rotation speed (Nc) of the compressor (22) reaches the maximum rotation speed (Ncmax), the fluctuation amount per control of the inside air side air mix door (16b) is determined as the outside air side air mix door (16a). The control is performed so that the temperature of the inside / outside air two-layer air conditioning unit (1) is increased while the temperature difference between both the inside and outside air is kept within an allowable temperature. An air conditioner for a vehicle.   The air conditioning system for vehicles according to claim 1, wherein the outside air passage is connected to a defroster outlet (37a) and a face outlet (37b), and the inside air passage is connected to a foot outlet (37c). apparatus.   The amount of fluctuation per control of the inside air side air mix door (16b) and the outside air side air so that the inside air and outside air blowing temperatures of the inside / outside air two-layer air conditioning unit (1) are within a predetermined allowable range. The vehicle air conditioner according to claim 1 or 2, wherein the amount of change per control of the mix door (16a) is controlled.   The refrigeration cycle apparatus includes the compressor (22), the indoor condenser (12), the first throttle (26a), the outdoor heat exchanger (24), the accumulator (25), and the compressor (22) in this order. A main refrigerant circuit that is arranged and circulates the refrigerant, and branches out downstream of the outdoor heat exchanger (24) with respect to the main refrigerant circuit, and a third throttle (27), the indoor evaporator (11) The vehicular air conditioner according to any one of claims 1 to 3, wherein the vehicular air conditioner is configured by a bypass circuit that is arranged in the order of and merges upstream of the accumulator (25).   In the main refrigerant circuit, a gas-liquid separator (50) and a second throttle (26b) are inserted in this order between the first throttle (26a) and the outdoor heat exchanger (24). The vehicle air conditioner according to claim 4, wherein the intermediate-pressure gas-phase refrigerant separated from the separator (50) is injected into the compressor (22).   The blower (7) can be driven independently for each of the outside air side passage and the inside air side passage, and the amount of each air blow can be adjusted. The vehicle air conditioner according to Item.   The inside / outside air two-layer air conditioning unit (1) includes an outside air mode in which only outside air flows in the outside air passage and the inside air passage, an inside air mode in which only inside air flows, outside air in the outside air passage, and inside / outside air 2 in which inside air flows in the inside air passage. An inside / outside air switching device (33) that can be switched to a stratified mode is provided, and the inside / outside air switching device (33) can independently adjust the intake air volume of the outside air side passage and the inside air side passage. The vehicle air conditioner according to any one of claims 1 to 6.

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