JP4561014B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner capable of automatically controlling switching between a suction port mode between an inside air mode and an outside air mode.
[0002]
[Prior art]
In a vehicle air conditioner that includes an evaporator that evaporates refrigerant circulating through a compressor and cools air, and that can automatically control switching between an intake air mode and an outside air mode, conventionally, a target blowout temperature TAO has been At the time of cool-down that is equal to or lower than the first predetermined temperature (for example, −12 ° C. when traveling at 40 km / h), the cool-down performance is immediately achieved by switching to the inside air mode. On the other hand, during a normal cooling operation in which the target blowing temperature TAO is equal to or higher than a second predetermined temperature (for example, −5.5 ° C. when traveling at 40 km / h), a fresh feeling is obtained by switching to the outside air mode.
[0003]
[Problems to be solved by the invention]
However, if the outside air mode is uniformly set during normal cooling operation, the power saving of the compressor drive source may be impaired. For example, even if the target outlet temperature TAO is in the normal cooling temperature range (TAO ≧ −5.5 ° C. (during 40 km / h traveling)), if the inside air enthalpy ir is smaller than the outside air enthalpy io, the inside air The mode will save power for the compressor drive source.
[0004]
In view of the above points, an object of the present invention is to surely save power in a compressor drive source of a vehicle air conditioner.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, the air conditioning duct (10a) that forms the air passage (10a) through which air is blown toward the vehicle interior and the air passage (10a) are arranged. An evaporator (45) that cools the air, and a compressor (41) that compresses and discharges the refrigerant that has passed through the evaporator (45).An internal air intake port (11) for taking in the internal air into the air passage (10a), an external air intake port (12) for taking in the external air into the air passage (10a), an internal air intake port (11) and an external air intake port (12). Inside / outside air switching damper (13) to open and closeWith
  In the air passage (10a)From inside air inlet (11)Inside air mode for introducing inside air and the air passage (10a)From outside air inlet (12)Switching between inlet mode and outside air mode that introduces outside airBy inside / outside air switching damper (13)In vehicle air conditioners that can be controlled automatically,
  Inside air temperature sensor (71) for detecting inside air temperature (TR), outside air temperature sensor (72) for detecting outside air temperature (TAM), and downstream portion of inside / outside air switching damper (13) in air passage (10a) One humidity sensor (77) provided in the
  When the suction port mode is switched to one of the inside air mode and the outside air mode, by periodically switching to the other mode, one humidity sensor (77) can be used before and after switching the suction port mode. The inside air humidity (RHr) and the outside air humidity (RHo) are detected,
  During the cooling operation in which the compressor (41) is driven to cool the air by the evaporator (45),Based on the inside air humidity (RHr) detected by one humidity sensor (77) and the inside air temperature (TR) detected by the inside air temperature sensor (71), the inside air enthalpy (ir) is calculated and one The outside air enthalpy (io) is calculated based on the outside air humidity (RHo) detected by the humidity sensor (77) and the outside air temperature (TAM) detected by the outside air temperature sensor (72),
  Periodic enthalpy (ir) of inside air and enthalpy (io) of outside air periodicallyCompared with the size, switching of the inlet mode is automatically controlled so as to introduce the air having the smaller enthalpy out of the inside air and the outside air.
[0006]
Thereby, since air with a smaller enthalpy out of the inside air and the outside air is introduced, it is possible to reliably save the power of the drive source of the compressor (41).
[0009]
  Further, in the first aspect of the present invention, when the suction port mode is switched to one of the inside air mode and the outside air mode, by periodically switching to the other mode, one humidity sensor ( 77) detects the inside air humidity (RHr) and the outside air humidity (RHo) before and after the switching of the inlet mode, so the inside air humidity (RHr) and the outside air humidity (RH) are detected by one humidity sensor (77). Both RHo) can be detected, and the enthalpy (ir) of the inside air and the enthalpy (io) of the outside air can be calculated. Therefore,Compared to an air conditioner having one inside air humidity sensor and one outside air humidity sensor, the number of parts can be reduced, and the cost can be reduced.
[0010]
  Claims2In the invention described in (1), a characteristic map indicating a change in the air blowing air volume corresponding to a change in the target air blowing temperature (TAO) of the air blown into the passenger compartment is provided, and the air blowing air volume is automatically controlled based on the characteristic map. The characteristic map in the inside air mode is characterized by being offset in a direction in which the amount of blown air becomes smaller than the characteristic map in the outside air mode.
[0011]
  Here, regarding the noise generated when air flows through the air passage (10a), the noise level in the inside air mode is generally higher than that in the outside air mode. In contrast, the above claims2According to the invention described in (5), since the blown air volume is smaller in the inside air mode than in the outside air mode, the noise level in the inside air mode can be reduced.
[0012]
  By the way, during cool-down (for example, when the target blowing temperature is -12 ° C. or lower when traveling at 40 km / h), the vehicle can be driven in a shorter time than saving the drive source of the compressor (41). Indoor temperatureDeclineSometimes you want to give priority to In such a caseIn addition,Claim3If the deviation between the set temperature (Tset) set by the occupant and the inside air temperature (TR) is larger than a predetermined value, the enthalpy (ir, io) is related to the magnitude. Switch to shy modeCan reduce the cabin temperature in a short time,Is preferred.
[0013]
  Claims4In the invention described in the above, it is estimated whether or not the window glass (3) of the vehicle is in a state of being easily fogged, and if it is estimated to be in a state of being easily fogged, the enthalpy (ir, io) is related to the magnitude. It is characterized by switching to the outside air mode.
[0014]
  By the way, conventionally, since the outside air mode was uniformly set during normal cooling operation, fogging of the window glass did not become a problem. However, according to the invention of claim 1, the air having the smaller enthalpy of the inside air and the outside air In most cases during normal cooling operation, ir ≦ io, and cooling operation is performed in the inside air mode for a long time, so that fogging of the window glass may be a problem. In such a caseIn addition,Claims above4If the invention described in the above is applied, it is possible to save power of the drive source of the compressor (41) while preventing fogging of the window glass.
[0015]
Note that, as an example of estimating whether or not it is likely to be cloudy, when the compressor (41) is operating, the absolute humidity of the air that has passed through the evaporator (45) is low, and the window glass tends to be cloudy. When the compressor (41) is stopped, it is assumed that the absolute humidity of the air that has passed through the evaporator (45) is high and the window glass is likely to be cloudy. It is done.
[0016]
Incidentally, in Japanese Patent Laid-Open No. 5-345515, the required blowing temperature is obtained based on the window glass temperature estimated from the outside air temperature and the inside air temperature, and the lower temperature is compared with the requested blowing temperature and the target blowing temperature. By controlling the operation of the compressor so as to be, an air conditioner that ensures anti-fogging properties and comfort has been proposed. However, since the air conditioner described in this publication does not introduce the air having the smaller enthalpy out of the inside air and the outside air as in the present invention, the power saving of the compressor drive source cannot be achieved.
[0017]
  Moreover, in estimating whether the window glass (3) of a vehicle is in the state which is easy to fog, it is claimed.5In the invention described in (1), an infrared sensor for detecting the temperature of the window glass (3) of the vehicle is provided, and the window glass temperature detected by the infrared sensor (78)OneBased on the inside air humidity (RHr) detected by the humidity sensor (77), it is estimated whether or not the window glass (3) is in a state of being easily fogged. It is characterized by switching to the outside air mode regardless of the magnitude of both enthalpies (ir, io).
[0018]
  This1 humiditySince it is possible to estimate whether or not the window glass (3) is in a cloudy state by using the inside air humidity (RHr) detected by the sensor (77), a new sensor is not required. Cost reduction can be achieved by reducing the number of parts.
[0019]
  Claims6In the invention described in the above, CO that detects the carbon dioxide concentration in the inside air₂Concentration detection means, CO₂When the concentration of carbon dioxide detected by the concentration detection means is larger than a predetermined value, the outside air mode is switched regardless of the magnitude of both enthalpies (ir, io).
[0020]
  By the way, conventionally, since the outside air mode was uniformly set during the normal cooling operation, the increase in the carbon dioxide concentration in the passenger compartment was not a problem. However, according to the invention of claim 1, the enthalpy of the inside air and the outside air is reduced. When the smaller air is introduced, in most cases during normal cooling operation, ir ≦ io, and the cooling operation is performed in the inside air mode for a long time, which may cause an increase in carbon dioxide concentration. In such a caseIn addition,Claims above6If the invention described in (3) is applied, it is possible to save power of the drive source of the compressor (41) while preventing an increase in the carbon dioxide concentration.
[0021]
In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 show an embodiment of the present invention. FIG. 1 is a schematic diagram showing an overall configuration of a vehicle air conditioner. FIG. 2 is a block diagram showing a control system of the vehicle air conditioner. It is.
[0023]
  The air conditioner of the present embodiment includes each air conditioner (actuator) of the air conditioner unit 1 that air-conditions the passenger compartment.As shown in FIG.Air conditioning control device (hereinafter referred to as air conditioner ECU)2This is an auto air conditioner configured to automatically control the temperature in the vehicle interior to the set temperature at all times.
[0024]
As shown in FIG. 1, an air conditioner unit 1 includes an air conditioning duct 10 that forms an air passage 10 a through which air is blown toward a vehicle interior, a centrifugal blower 30 that generates an air flow in the air conditioning duct 10, and an air conditioning duct. The refrigeration cycle 40 for cooling the air flowing in the vehicle 10 to cool the vehicle interior, the cooling water circuit 50 for heating the air flowing in the air conditioning duct 10 to heat the vehicle interior, and the like.
[0025]
The air conditioning duct 10 is disposed on the front side of the vehicle interior. The most upstream side (windward side) of the air-conditioning duct 10 is a portion constituting a suction port switching box (inside / outside air switching box) 10b. It has an outside air inlet 12 for taking in (hereinafter referred to as outside air). Furthermore, an inside / outside air (suction port) switching damper 13 is rotatably attached to the inside of the inside air suction port 11 and the outside air suction port 12. The inside / outside air switching damper 13 is driven by an actuator 14 (see FIG. 2) such as a servo motor, and switches the suction low mode between the inside air mode and the outside air mode. The inside / outside air switching damper 13 constitutes inside / outside air switching means together with the suction port switching box 10b.
[0026]
Moreover, the most downstream side (leeward side) of the air-conditioning duct 10 is a portion constituting the outlet switching box, and a defroster opening, a face opening, and a foot opening are formed. A defroster duct 15 is connected to the opening portion of the defroster, and a defroster outlet 18 for blowing mainly hot air toward the inner surface of the front window glass 3 of the vehicle opens at the most downstream end of the defroster duct 15. ing.
[0027]
In addition, a face duct 16 is connected to the face opening, and a face air outlet 19 that blows mainly cool air toward the head and chest of the occupant is opened at the most downstream end of the face duct 16. Further, a foot duct 17 is connected to the foot opening, and a foot outlet 20 that blows mainly warm air toward the feet of the occupant is opened at the most downstream end of the foot duct 17.
[0028]
And the two blower outlet switching dampers 21 are rotatably attached inside each blower outlet. The two outlet switching dampers 21 are driven by an actuator 22 (see FIG. 2) such as a servo motor, and the outlet mode is set to any one of a face mode, a bi-level mode, a foot mode, a foot differential mode, and a defroster mode. Switch.
[0029]
Incidentally, in the face mode, the entire amount of the conditioned air is blown out from the face air outlet 19, in the bi-level mode, the air conditioned air is blown out from the face air outlet 19 and the foot air outlet 20, and in the foot mode, most of the air conditioned air (all the air is blown out). About 80% of the air volume) is blown out from the foot outlet 20 and part of the conditioned air is blown out from the defroster outlet 18. Further, in the foot differential mode, the air is blown from the defroster outlet 18 and the foot outlet 20, and specifically, the amount of air blown from the defroster outlet 18 is about 40% of the total amount of blown air, at least 1/3 of the total amount of blown air. Set as above. Further, in the defroster mode, the entire amount of conditioned air is blown out from the defroster outlet 18. Note that the two outlet switching dampers 21 form an outlet switching means together with the outlet switching box.
[0030]
The centrifugal blower 30 includes a centrifugal fan 31 that is rotatably accommodated in a scroll case that is integrally formed with the air conditioning duct 10, and a blower motor 32 that rotationally drives the centrifugal fan 31. The blower motor 32 controls the amount of blown air (the rotational speed of the centrifugal fan 31) based on the blower terminal voltage (hereinafter referred to as blower voltage) applied via the blower drive circuit 33 (see FIG. 2).
[0031]
The refrigeration cycle 40 is driven by a belt to the engine 6 to compress a refrigerant 41, a condenser 42 for condensing and liquefying the compressed refrigerant, and gas-liquid separation of the condensed and liquefied refrigerant to flow only the liquid refrigerant downstream. The liquid receiver 43 includes an expansion valve 44 that decompresses and expands the liquid refrigerant, an evaporator 45 that evaporates and vaporizes the decompressed and expanded refrigerant, and a refrigerant pipe that connects these in an annular shape.
[0032]
Among these, the evaporator 45 is arrange | positioned in the air-conditioning duct 10 so that the air passage may be obstruct | occluded the whole surface, and performs the air dehumidification effect | action which dehumidifies the air cooling action which cools the air which passes self, and the air which passes self. It is an indoor heat exchanger. In other words, the evaporator 45 is a cooling heat exchanger that cools and dehumidifies the conditioned air by the operation of the compressor 41.
[0033]
The compressor 41 is connected to an electromagnetic clutch 46 as clutch means for intermittently transmitting the rotational power from the engine 6 to the compressor 41. The electromagnetic clutch 46 is controlled by a clutch drive circuit 47 (see FIG. 2) (in the case of the variable displacement compressor 41, the discharge pressure is controlled).
[0034]
When the electromagnetic clutch 46 is energized, the rotational power of the engine 6 is transmitted to the compressor 41 and the air cooling action by the evaporator 45 is performed. At this time, the discharge capacity of the refrigerant discharged from the discharge port of the compressor 41 changes in proportion to the rotational speed of the engine 6. Further, when energization of the electromagnetic clutch 46 is stopped, the engine 6 and the compressor 41 are shut off, and the air cooling action by the evaporator 45 is stopped. Here, the condenser 42 is disposed in a place where it is easy to receive traveling wind generated when the vehicle travels, and the outdoor heat exchange for exchanging heat between the refrigerant flowing in the interior, the outside air blown by the cooling fan 48, and the traveling wind. It is a vessel.
[0035]
The cooling water circuit 50 is a circuit that circulates the cooling water heated by the water jacket of the engine 6 by a water pump (not shown), and has a radiator, a thermostat (all not shown), and a heater core 51. In the heater core 51, cooling water for cooling the engine 6 flows inside, and the cooling air is reheated using the cooling water as a heat source for heating.
[0036]
The heater core 51 is disposed downstream of the evaporator 45 in the air conditioning duct 10 so as to partially block the air passage. An air mix damper 52 is rotatably attached to the air upstream side of the heater core 51. This air mix damper 52 is driven by an actuator 53 (see FIG. 2) such as a servo motor, and adjusts the ratio of the amount of air passing through the heater core 51 and the amount of air bypassing the heater core 51 according to the stop position. It functions as a blowing temperature adjusting means for adjusting the blowing temperature of the air blown into the passenger compartment.
[0037]
Next, the configuration of the control system of the present embodiment will be described with reference to FIG. 1, FIG. 2, and FIG. Switch signals from the switches on the control panel P provided on the front surface of the vehicle interior and sensor signals from the sensors are input to the air conditioner ECU 2. The air conditioner ECU 2 controls the operation of the air conditioner based on these signals.
[0038]
Here, the switches on the control panel P are, as shown in FIG. 3, an air conditioner (A / C) switch 60 and an economy (ECO) switch 61 for instructing operation and stop of the air conditioner, and a suction low mode. A suction port changeover switch 62 for switching the temperature, a temperature setting lever 63 for setting the temperature in the passenger compartment to a desired temperature, an air volume switching lever 64 for switching the air flow rate of the centrifugal fan 31, and an outlet mode. For example, the air outlet changeover switches 65 to 70 are provided.
[0039]
Among these, the A / C switch 60 is an air conditioner operation switch that commands a cool mode in which the comfort in the passenger compartment is emphasized. Further, the ECO switch 61 is an economy mode in which air conditioning is performed by setting the cooling degree of the conditioned air by the evaporator 45 to be lower than that in the cool mode, specifically, the ON / OFF temperature of the compressor 41 is set to 4 in the cool mode. This is an air conditioner operation switch for instructing an economy mode in which fuel economy (fuel efficiency) is set to 13 [deg.] C. ON and 12 [deg.] C. OFF with respect to [deg.] C. and 3 [deg.] C.
[0040]
The air volume switching lever 64 is an OFF position where the energization of the blower motor 32 is stopped, an AUTO position where the blower voltage of the blower motor 32 is automatically controlled, an LO position where the blower voltage applied to the blower motor 32 is minimized, and the blower motor 32 is set to the minimum air volume. It is possible to operate the ME position where the blower voltage to be applied to the intermediate value is the intermediate air volume and the HI position where the blower voltage applied to the blower motor 32 is the maximum value and the maximum air volume is set.
[0041]
The outlet switch includes a face (FACE) switch 65 for fixing to the FACE mode, a high level (B / L) switch 66 for fixing to the B / L mode, and a foot (FOOT) for fixing to the FOOT mode. ) Switch 67, foot differential (F / D) switch 68 for fixing to F / D mode, defroster (DEF) switch 69 for fixing to DEF mode, and auto (AUTO) switch 70 for automatically controlling the outlet mode There is.
[0042]
As shown in FIG. 2, each sensor includes an inside air temperature sensor 71 that detects an air temperature inside the vehicle interior (hereinafter referred to as an inside air temperature), and an outside air temperature that detects an air temperature outside the vehicle interior (hereinafter referred to as an outside air temperature). Sensor 72, solar radiation sensor 73 for detecting the amount of solar radiation irradiated into the vehicle interior, post-evaporation temperature sensor 74 for detecting the air cooling temperature of the evaporator 45, and engine coolant temperature (cooling water temperature) flowing into the heater core 51 A cooling water temperature sensor 75 to detect, a vehicle speed sensor 76 to detect the vehicle speed of the vehicle 5, a humidity sensor (inside air humidity sensor, outside air humidity sensor) 77 to detect the relative humidity of the inside air and the outside air, and the temperature of the front window glass 3 are detected. Window glass temperature sensor 78, CO that detects the carbon dioxide concentration in the cabin air (inside air)₂Sensor (CO₂Density detecting means) 79 and the like.
[0043]
Among these, the post-evaporation temperature sensor 74 is specifically composed of a thermistor that is disposed immediately after the evaporator 45 and detects an air temperature immediately after passing through the evaporator 45 (hereinafter referred to as post-evaporation temperature). Moreover, the humidity sensor 77 is arrange | positioned in the air flow upstream part of the centrifugal fan 31 among the air passages 10a, for example, the humidity sensor 77 is arrange | positioned in the suction inlet of the fan 31, and is suitable. Thereby, the relative humidity of the inside air is detected in the inside air mode, and the relative humidity of the outside air is detected in the outside air mode. Further, if an infrared sensor is employed as the window glass temperature sensor 78, the window glass temperature can be accurately detected, which is preferable.
[0044]
Next, control processing of the air conditioner ECU 2 of the present embodiment will be described based on FIGS. 4 to 7. Here, FIG. 4 is a flowchart showing basic control processing by the air conditioner ECU 2.
[0045]
The air conditioner ECU 2 includes a microcomputer (not shown) including a CPU, ROM, RAM, and the like, and sensor signals from the sensors 71 to 79 are A / D converted by an input circuit (not shown) in the air conditioner ECU 2. After that, it is configured to be input to the microcomputer.
[0046]
First, when the ignition switch is turned on and DC power is supplied to the air conditioner ECU 2, the routine of FIG. 4 is started to perform each initialization and initial setting (step S1).
[0047]
  Next, switch signals from the temperature setting lever 63 and other switchesIssueReading, inside air temperature sensor 71, outside air temperature sensor 72, solar radiation sensor 73, post-evaporation temperature sensor 74, cooling water temperature sensor 75, vehicle speed sensor 76WetDegree sensor 77, Window glass temperature sensor 78, and CO ₂ Sensor 79The sensor signal from is read after A / D conversion (step S2).
[0048]
Subsequently, a target blowing temperature (TAO) of air blown into the vehicle interior is calculated based on the following formula 1 stored in advance in the ROM (step S3).
[0049]
[Expression 1]
TAO = KSET × TSET−KR × TR−KAM × TAM−KS × TS + C where TSET is a set temperature set by the temperature setting lever 63, TR is an inside air temperature detected by the inside air temperature sensor 71, and TAM is an outside air temperature sensor. The outside air temperature detected at 72 and TS are the amount of solar radiation detected by the solar radiation sensor 73. KSET, KR, KAM, and KS are gains, and C is a correction constant.
[0050]
  Next, the suction low mode is determined to be either the inside air mode or the outside air mode (step S4). The inside air mode is a suction port mode in which the inside / outside air switching damper 13 is set to the position indicated by a two-dot chain line in FIG. 1 and the inside air is sucked from the inside air suction port 11. The outside air mode refers to the inside / outside air switching damper 13.1This is a suction port mode in which the outside air is sucked from the outside air suction port 12 by setting it to the solid line position.
[0051]
And at the time of the heating operation which stops the drive of the compressor 41, let an inlet mode be an external air mode. On the other hand, during the cooling operation in which the compressor 41 is driven and the evaporator 45 cools the air, the suction port mode is determined based on a flowchart shown in FIG.
[0052]
Next, the blower voltage (voltage applied to the blower motor 32) corresponding to the target blowing temperature is determined from the characteristic diagram (see FIG. 5) stored in advance in the ROM (step S5). Here, when the suction port mode is determined to be the outside air mode in step S4, the characteristic map shown by the solid line A in FIG. 5 is adopted. On the other hand, when the suction port mode is determined to be the inside air mode, the characteristic map shown in the dotted line B of FIG. 5 that is offset in the direction in which the blower voltage becomes smaller than the characteristic map of the solid line A is adopted.
When the air volume switching lever 64 is selected by manual operation, the selected air volume is set.
[0053]
Next, when the auto switch 70 is operated and the auto mode is selected, the blowing mode corresponding to the target blowing temperature is determined from the characteristic chart (see FIG. 6) stored in advance in the ROM (step S6). . In this blowing mode, as the target blowing temperature rises from the low temperature side to the high temperature side, the face mode → bilevel mode → foot mode is switched. In addition, when any of the blower outlet change-over switches 65-69 is selected by manual operation, the selected blower outlet mode is set.
[0054]
Next, the target damper opening (SW) of the air mix damper 52 is calculated based on the following formula 2 stored in advance in the ROM (step S7).
[0055]
[Expression 2]
SW = {(TAO-TE) / (TW-TE)} × 100 (%)
TE is the post-evaporation temperature detected by the post-evaporation temperature sensor 74, and TW is the cooling water temperature detected by the cooling water temperature sensor 75.
[0056]
When calculated as SW ≦ 0 (%), the air mix damper 52 is controlled to a position (MAXCOOL position) in which all of the cool air from the evaporator 45 is bypassed from the heater core 51. Further, when calculated as SW ≧ 100 (%), the air mix damper 52 is controlled to a position (MAXHOT position) through which all the cold air from the evaporator 45 passes through the heater core 51. Further, when calculated as 0 (%) <SW <100 (%), the air mix damper 52 passes a part of the cool air from the evaporator 45 through the heater core 51 and bypasses the rest of the cool air from the heater core 51. Controlled.
[0057]
Next, ON / OFF of the compressor 41 is determined (step S8). Specifically, the target evaporator outlet temperature TEO is calculated based on the TAO and the outside air temperature TAM, and the actual evaporator outlet temperature TE and the target evaporator outlet temperature TEO are compared. When TE> TEO, The compressor is turned on, and when TE ≦ TEO, the compressor is turned off.
[0058]
Next, control signals are output to the actuators 14, 22, 53, the blower drive circuit 33, and the clutch drive circuit 47 so that the control states calculated or determined in steps S3 to S8 are obtained (steps). S9).
[0059]
Next, the suction port mode determination flow at the time of cooling operation in step S4 will be described based on FIG.
[0060]
First, the outside air mode is forcibly switched to introduce the outside air into the suction port switching box 10b, and the state of the outside air mode is maintained for a predetermined time (for example, about 10 seconds) (step S40).
[0061]
Then, the relative humidity (outside air humidity) RHo detected by the humidity sensor 77 and the outside air temperature TAM detected by the outside air temperature sensor 72 are read, and the enthalpy of the outside air io based on the relative humidity RHo and the outside air temperature TAM. Is calculated (step S41). Specifically, a known wet air diagram can be stored in the ROM in advance, and the enthalpy io of the outside air can be calculated from the relative humidity RHo of the outside air and the outside air temperature TAM on this wet air diagram.
[0062]
Next, the internal air mode is forcibly switched to introduce the internal air into the suction port switching box 10b, and the state of the internal air mode is maintained for a predetermined time (for example, about 10 seconds) (step S42).
[0063]
Then, the relative humidity (inside air humidity) RHr detected by the humidity sensor 77 and the inside air temperature TR detected by the inside air temperature sensor 71 are read, and the enthalpy of the inside air ir based on the relative humidity RHr and the inside air temperature TR. Is calculated (step S43). Specifically, the enthalpy io of the inside air can be calculated from the relative humidity RHr of the inside air and the inside air temperature TR on the wet air diagram.
[0064]
Next, the enthalpy io of outside air and the enthalpy ir of inside air are compared in magnitude (step S44). If the enthalpy ir of inside air is equal to or less than the enthalpy io of outside air (ir ≦ io), CO₂CO detected by sensor 79₂It is determined whether or not the density is a predetermined value (for example, 0.17%) or less (step S45).
And further, CO₂If the concentration is equal to or lower than the predetermined value, it is estimated whether or not the window glass 3 is in a state of being easily fogged (step S46), and if it is not estimated to be in a state of being easily fogged, the inlet mode is determined to be the inside air mode (step S47). .
[0065]
On the other hand, in step S45, the CO₂If the concentration is greater than the predetermined value, or if it is estimated that it is likely to be cloudy in step S46, the suction port mode is determined to be the outside air mode (step S49).
[0066]
When the enthalpy io of the outside air is smaller than the enthalpy ir of the inside air (io <ir) in step S44, the deviation (| Tset−TR |) between the set temperature Tset and the inside air temperature TR is a predetermined value (for example, 3 It is determined whether it is larger than (° C.) (step S48). When the deviation between the set temperature Tset and the inside air temperature TR is larger than a predetermined value (| Tset−TR |> 3), it is considered that the cool-down control is being performed, and the suction port mode is determined as the inside air mode. (Step S47).
[0067]
On the other hand, when the deviation between the set temperature Tset and the inside air temperature TR is equal to or less than a predetermined value (| Tset−TR | ≦ 3), it is considered that the cool-down control is not being performed, and the suction port mode is determined as the outside air mode. (Step S49).
[0068]
When the suction port mode is determined in steps S47 and S49, the determined suction port mode is maintained for a predetermined time (for example, 10 minutes). That is, step S4 is skipped until a predetermined time has elapsed, and the process proceeds from step S3 to step S5. And when predetermined time passes, both enthalpies io and ir are compared again by step S4, and a suction inlet mode is determined.
[0069]
Accordingly, when the mode is switched to one of the suction port modes, the mode is periodically switched to the other mode, for example, in 10 minutes (steps S40 and S42).
Since the humidity sensor 77 is arranged in the air flow upstream portion of the centrifugal fan 31 in the air passage 10a, the single humidity sensor 77 detects the outside air humidity RHo and the inside air humidity RHr before and after switching. Then (steps S41 and S43), both enthalpies ir and io are periodically compared in magnitude (step S44).
[0070]
In addition, when the suction inlet switch 62 is selected by manual operation, the selected suction inlet mode is set.
[0071]
Next, the operation of the vehicle air conditioner configured as described above will be briefly described.
[0072]
When the A / C switch 60 or the ECO switch 61 is turned on, the operation and stop of the compressor 41 are controlled so that the post-evaporation temperature TE becomes a predetermined temperature, and the air sucked into the air conditioning duct 10 After being cooled when passing through 45, it is reheated when passing through the heater core 51, and the temperature of the air blown into the passenger compartment is adjusted to the target blowing temperature TAO. As a result, the temperature in the passenger compartment is controlled to the set temperature TSET set by the passenger operating the temperature setting lever 63.
[0073]
As described above, according to the present embodiment, in step S4, the enthalpies ir and io of the inside air and the outside air are calculated in the cooling operation, the calculated enthalpies ir and io are compared in magnitude, and the switching of the inlet mode is performed. In addition, automatic control is performed so as to introduce the air having the smaller enthalpy out of the outside air. Therefore, since the air having the smaller enthalpy out of the inside air and the outside air is introduced, the power saving of the engine 6 serving as the drive source of the compressor 41 can be reliably achieved.
[0074]
Here, at the time of cool-down, there is a case where priority is given to lowering the vehicle interior temperature TR in a short time rather than to save power of the engine 6 that is a drive source of the compressor 41. In contrast to this case, according to the present embodiment, even if io <ir in step S44, the inside air mode is set if it is determined in step S48 that the engine is in a cool-down state, so both enthalpies ir, io Regardless of the size, the inside air mode is set, and priority can be given to lowering the vehicle interior temperature TR in a short time.
[0075]
Further, according to the present embodiment, during normal cooling operation other than during cool-down, in most cases, ir ≦ io, and without steps S45 and S46, the cooling operation is performed in the long-time inside air mode. However, when the inside air mode is continued for a long time, fogging of the window glass and an increase in the carbon dioxide concentration in the passenger compartment become problems.
[0076]
On the other hand, in this embodiment, steps S45 and S46 are provided, and even if ir ≦ io in step S44, if the carbon dioxide concentration is larger than the predetermined value in step S45 or if the window glass is in step S46. When it is determined that it is likely to be cloudy, the outside air mode is set, so that the window glass is prevented from being fogged and the increase in the carbon dioxide concentration in the passenger compartment is suppressed, while the engine 6 serving as the drive source of the compressor 41 is saved. Motorization can be achieved.
[0077]
Here, in order to confirm the effect of this power saving, the present inventors set the vehicle thermal load during cooling operation (cooling load) when stopped, when traveling at 40 km / h in the inside air mode, and at 40 km / h in the outside air mode. Measured in each state during running. As experimental conditions, the outside air temperature is 35 ° C., the relative humidity of the outside air is 60% RH, and the solar radiation amount is 1000 W / m.²The vehicle interior temperature at the time of traveling stop is 30 ° C., and the vehicle interior temperature at the time of travel is 25 ° C. The number of occupants during traveling is one.
[0078]
The bar graph shown in FIG. 8 shows the results of the above-mentioned experiment. In the figure, symbol A is a thermal load due to solar radiation irradiated from the glass of the vehicle into the vehicle interior, and symbol B is from the vehicle body to the vehicle interior. Reference numeral C is a thermal load due to the vehicle becoming a heat mass when the vehicle is stopped, reference numeral D is a thermal load due to ventilation loss in which the inside air and the outside air are switched during traveling, and reference numeral E is an occupant It is a heat load due to heat generation.
[0079]
As shown in this experimental result, about half of the heat load of the vehicle in the outside air mode is the heat load due to the ventilation loss D, and the total heat load (2900 W) in the inside air mode is the heat load in the outside air mode. It is about half of the total (6120W). Therefore, according to the present embodiment in which the cooling operation is performed in the inside air mode for a long time, the power saving of the drive source of the compressor 41 can be greatly improved.
[0080]
Moreover, according to this embodiment, when it switches to one mode among suction inlet modes, it switches periodically to the other mode. Since the humidity sensor 77 is disposed in the air flow upstream portion of the centrifugal fan 31 in the air passage 10a, the single humidity sensor 77 detects the outside air humidity RHo and the inside air humidity RHr before and after switching. can do. Therefore, the number of parts can be reduced and the cost can be reduced as compared with an air conditioner including one inside air humidity sensor and one outside air humidity sensor.
[0081]
Even if the inside air mode is continued for a long time, the thirst of the occupant does not matter. Specifically, experiments have confirmed that even if the relative humidity RHr in the passenger compartment is 0%, the thirst is not thirsty for at least 3 hours after the last hydration of the occupant.
[0082]
(Other embodiments)
In step S47 shown in FIG. 7 of the above embodiment, the inside / outside air switching damper 13 is set to the inside air mode in which it is set at the two-dot chain line position in FIG. 1, but the present invention is not limited to this. The air switching damper 13 may be set at a position slightly closer to the solid line position from the two-dot chain line position in FIG. 1 to be in a partially outside air mode in which a part of the outside air is introduced in addition to the inside air.
[0083]
Further, the humidity sensor 77 in the above embodiment may be a temperature / humidity sensor, and the inside air temperature sensor 71 and the outside air temperature sensor 72 may be eliminated.
[0084]
In the flowchart shown in FIG. 7 of the above embodiment, steps S45, S46, and S48 are provided, but these steps may be omitted. Moreover, you may make it select and provide arbitrary steps among these steps.
[0085]
In the above embodiment, the humidity RHr and RHo of the inside air and the outside air are detected by the single humidity sensor 77. However, the humidity sensor that detects the inside air humidity RHr, the humidity sensor that detects the outside air humidity RHo, and May be provided separately. In this case, it is not necessary to periodically switch to the other mode, and the control can be simplified. Moreover, the enthalpy ir of inside air and the enthalpy io of outside air can always be compared in magnitude.
[0086]
In the above embodiment, the suction port mode is determined based on the flowchart shown in FIG. 7 during the cooling operation in which the compressor 41 is driven and the evaporator 45 cools the air. During the cooling operation in which the temperature is equal to or higher than a predetermined temperature (for example, −20 ° C.), the suction port mode may be determined based on the flowchart shown in FIG.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a vehicle air conditioner showing an embodiment of the present invention.
2 is a block diagram showing a control system of the air conditioner of FIG. 1;
FIG. 3 is a diagram showing details of the control panel of FIG. 2;
4 is a flowchart showing basic control processing by the air conditioner ECU of FIG. 2; FIG.
FIG. 5 is a characteristic diagram showing a relationship between a target blowing temperature and a blower voltage.
FIG. 6 is a characteristic diagram showing a relationship between a target outlet temperature and an outlet mode.
7 is a flowchart showing details of a suction port mode determination step in FIG. 4;
FIG. 8 is a graph showing experimental results for confirming the effect of power saving of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Air-conditioning duct, 10a ... Air passage, 41 ... Compressor, 45 ... Evaporator,
ir ... Shy enthalpy, io ... Outer enthalpy.

Claims (6)

An air conditioning duct (10) that forms an air passage (10a) through which air is blown toward the vehicle interior;
An evaporator (45) disposed in the air passage (10a) for cooling the air;
A compressor (41) for compressing and discharging the refrigerant that has passed through the evaporator (45) ;
An inside air inlet (11) for taking inside air into the air passage (10a);
An outside air inlet (12) for taking outside air into the air passage (10a);
An inside / outside air switching damper (13) for opening and closing the inside air suction port (11) and the outside air suction port (12) ,
An inlet mode of an inside air mode for introducing inside air from the inside air inlet (11) into the air passage (10a) and an outside air mode for introducing outside air from the outside air inlet (12) into the air passage (10a). In the vehicle air conditioner capable of automatically controlling switching by the inside / outside air switching damper (13) ,
An inside air temperature sensor (71) for detecting an inside air temperature (TR);
An outside temperature sensor (72) for detecting outside temperature (TAM);
A humidity sensor (77) provided in a downstream portion of the inside / outside air switching damper (13) in the air passage (10a),
When the suction port mode is switched to one of the inside air mode and the outside air mode, by periodically switching to the other mode, the one humidity sensor (77) becomes the suction port. The inside air humidity (RHr) and the outside air humidity (RHo) are detected before and after the mode switching.
During the cooling operation in which the compressor (41) is driven and the evaporator (45) cools the air, the room air humidity (RHr) and the room temperature sensor detected by the one humidity sensor (77). The inside air enthalpy (ir) is calculated based on the inside air temperature (TR) detected by (71), and the outside air humidity (RHo) detected by the one humidity sensor (77) and the outside air. Based on the outside air temperature (TAM) detected by the temperature sensor (72), the enthalpy (io) of the outside air is calculated,
The inside air enthalpy (ir) and the outside air enthalpy (io) are periodically compared in size, and the inlet mode switching is automatically controlled to introduce the air having the smaller enthalpy of the inside air and the outside air. An air conditioner for a vehicle. A characteristic map indicating a change in the blown air volume of the air corresponding to a change in a target blown temperature (TAO) of the air blown into the vehicle interior;
The blowing air volume can be automatically controlled based on the characteristic map,
2. The vehicle air conditioner according to claim 1 , wherein the characteristic map in the inside air mode is offset in a direction in which the amount of blown air becomes smaller than the characteristic map in the outside air mode. If the deviation of the set temperature set by the passenger and (Tset) and the inside air temperature (TR) is larger than a predetermined value, characterized in that switching the two enthalpy (ir, io) to the inside air mode regardless of the The air conditioner for vehicles according to claim 1 or 2 . Estimate whether the vehicle window glass (3) is prone to fogging,
If it is estimated to be cloudy easy state, the both enthalpy (ir, io) air-conditioning system according to claim 1 or 2, characterized in that switching to the outside air mode regardless of. An infrared sensor (78) for detecting the temperature of the window glass (3) of the vehicle;
Based on the window glass temperature detected by the infrared sensor (78) and the room air humidity (RHr), it is estimated whether or not the window glass (3) is in a state of being easily fogged.
If it is estimated to be cloudy easy state, the both enthalpy (ir, io) air-conditioning system according to claim 1 or 2, characterized in that switching to the outside air mode regardless of. CO ₂ concentration detection means for detecting the carbon dioxide concentration in the inside air,
If the carbon dioxide concentration detected by the CO ₂ concentration detector is larger than the predetermined value, the both enthalpy (ir, io) or claim 1, characterized in that switching to the outside air mode regardless of the The vehicle air conditioner according to 2 .

Images