JP3334410B2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle, which is suitable for preventing fogging of a window glass of the vehicle.

[0002]

2. Description of the Related Art Conventionally, in vehicle air conditioners, anti-fog control for preventing fogging of window glass has been performed (Japanese Utility Model Application Laid-Open No. 58-59611, Japanese Utility Model Application Laid-Open No. 59-14091).
No. 3). This anti-fogging control determines whether or not the window glass is fogged (anti-fogging determination) based on a comparison between the vehicle interior humidity and the anti-fogging determination value. The defrosting of the window glass is prevented by operating the refrigerant compressor of (1) to dehumidify the vehicle interior.

[0003]

However, in the conventional anti-fogging control, immediately after the operation of the refrigerant compressor is stopped, moisture condensed in the refrigerant evaporator re-evaporates as the temperature of the refrigerant evaporator rises. Then, the humidity of the blown air blown out from the blowout port into the vehicle compartment rises rapidly, and fogging occurs in the window glass.

At this time, if the humidity sensor for detecting the humidity in the vehicle compartment immediately detects the sudden rise of the humidity and operates the refrigerant compressor based on the detection, the fogging of the window glass can be prevented. It is possible. However, since it takes some time for the humidity sensor to detect the limit humidity at which fogging of the window glass occurs, it is not possible to remove the fogging of the window glass immediately after the refrigerant compressor is turned off.

An object of the present invention is to prevent fogging of a window glass due to re-evaporation of moisture condensed in a refrigerant evaporator immediately after the operation of a refrigerant compressor is stopped.

[0006]

According to the first aspect of the present invention, a refrigerant compressor (18) and a refrigerant evaporator (2) constituting a refrigeration cycle are provided.
2) and humidity detecting means (41) for detecting the humidity in the passenger compartment
And operating the refrigerant compressor (18) on the basis of the detected humidity in the vehicle cabin so as to operate the vehicle window glass (1).
0) In a vehicle air conditioner that performs anti-fogging,
Re-actuating means (step 90) for re-activating the refrigerant compressor (18) based on the detected change in humidity in the vehicle interior after the operation of the refrigerant compressor (18) is stopped.
2, 907 to 912).

According to a second aspect of the present invention, in the vehicle air conditioner according to the first aspect, the detected humidity in the cabin is compared with a predetermined value to determine whether it is necessary to prevent fogging. An anti-fog determination means (step 906) for performing fogging determination is provided, and the re-activation means (steps 902, 907 to 912)
When the result of the anti-fog determination is a result that the anti-fog is not necessary, based on the detected change state of the humidity in the vehicle interior after the operation of the refrigerant compressor (18) is stopped,
A technical means for restarting the refrigerant compressor (18) is adopted.

According to a third aspect of the present invention, in the vehicle air conditioner according to the first or second aspect, technical means is employed in which the change state is a change amount in a predetermined time. According to a fourth aspect of the present invention, in the vehicle air conditioner according to the first or second aspect, the change state is:
A technical measure of being a maximum value in a predetermined time is employed.

The reference numerals in parentheses of the above means indicate the correspondence with specific means described in the embodiments described later.

[0010]

According to the first to fourth aspects of the present invention, immediately after the operation of the refrigerant compressor is stopped, the humidity in the vehicle interior becomes cloudy due to the re-evaporation of the moisture condensed in the refrigerant evaporator. Even if the temperature rises to the maximum, the change in the humidity in the vehicle interior after the operation of the refrigerant compressor is stopped (the amount of change in the humidity in the invention according to the third embodiment, the change in the humidity according to the fourth embodiment). In this case, the refrigerant compressor can be restarted on the basis of the maximum value of humidity, so that fogging of the window glass can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a vehicle air conditioner according to the present invention will be described below with reference to FIGS. FIG.
FIG. 1 is an overall schematic diagram of the vehicle air conditioner. A vehicle air conditioner (hereinafter, referred to as an air conditioner) 1 includes a duct 2 for sending conditioned air into a vehicle interior, a blower 3 for introducing air into the duct 2 and sending the air into the vehicle interior, and a refrigeration unit that constitutes cooling means. A cycle 4, a hot water circuit 5 constituting heating means, and an air conditioner control device 6 (see FIG. 2) are provided.

At the downstream end of the duct 2, branch ducts 2a to 2a
c is connected. The branch duct 2a blows out the air toward the window glass 10 of the vehicle so that the defroster outlet 7
The branch duct 2b is connected to a face outlet 8 for blowing air toward the upper body of the occupant, and the branch duct 2c is connected to a foot outlet 9 for blowing air toward the feet of the occupant. These outlets 7 to 9 are selectively opened and closed by opening and closing of outlet switching dampers 11 and 12 provided at the upstream openings of the branch ducts 2a to 2c. The outlet switching dampers 11 and 12 are driven by drive means such as a servo motor 13 (see FIG. 2) via a link mechanism (not shown).

The blower 3 includes a blower case 3a, a centrifugal fan 3b, and a blower motor 3c, and the amount of air to be blown (the number of rotations of the blower motor 3c) is determined according to the voltage (blower voltage) applied to the blower motor 3c. The blower case 3a has an inside air inlet 14 for introducing vehicle interior air (inside air) and an outside air inlet 15 for introducing outside air (outside air).
Are formed, and an inside / outside air switching damper 16 for selectively opening and closing the inside air introduction port 14 and the outside air introduction port 15 is provided. The inside / outside air switching damper 16 is connected to, for example, a servo motor 17 (FIG. 2) via a link mechanism (not shown).
).

The refrigerating cycle 4 is a cooling means for cooling the interior of the vehicle and a fogging preventing means for removing fogging of the window glass, and includes a refrigerant compressor (comp.) 18, a refrigerant condenser 19, a receiver 20, a pressure reducing device. 21, refrigerant evaporator 22,
It is composed of functional components of an evaporating pressure regulating valve (hereinafter, referred to as EPR) 23 and is connected in a ring by a refrigerant pipe 24.

The refrigerant compressor 18 is driven by a vehicle engine 26 via an electromagnetic clutch 25, and compresses the sucked gas refrigerant to a high temperature and a high pressure and discharges it. The refrigerant condenser 19 receives the air from the cooling fan 27 and condenses and liquefies the high-temperature and high-pressure refrigerant discharged from the refrigerant compressor 18. The receiver 20 separates the refrigerant sent from the refrigerant condenser 19 into gas and liquid, and flows out only the liquid refrigerant.

The decompression device 21 decompresses and expands the liquid refrigerant introduced from the receiver 20 and sends it to the refrigerant evaporator 22.
This is a temperature-operated expansion valve that adjusts the flow rate of the passing refrigerant so that the degree of superheat of the refrigerant flowing through the outlet pipe of the refrigerant evaporator 22 is constant. The refrigerant evaporator 22 is disposed in the duct 2 and evaporates the low-temperature and low-pressure refrigerant decompressed by the decompression device 21 by heat exchange with the air sent from the blower 3.

The EPR 23 is provided between the refrigerant evaporator 22 and the refrigerant compressor 18, and keeps the evaporating pressure in the refrigerant evaporator 22 at a predetermined value or more (for example, 1.9 kg / cm ² ), thereby reducing heat generation. The frost of the refrigerant evaporator 22 at the time of load is prevented. The hot water circuit 5 is heating means for heating the interior of the vehicle, and is disposed downstream of the refrigerant evaporator 22 in the duct 2 and heats the air flowing through the duct 2 using the cooling water of the engine 26 as a heat source. And a hot water pipe 29 for annularly connecting the heater core 28 to a cooling water circuit (not shown) of the engine 26.

The heater core 28 is arranged in the duct 2 so as to form a bypass passage 30 in which air passing through the refrigerant evaporator 22 flows around the heater core 28. The ratio between the amount of air passing through the heater core 28 and the amount of air passing through the bypass path 30 is adjusted by an air mix damper 31 arranged on the windward side of the heater core 28. The air mix damper 31 is driven by a driving unit such as a servo motor 32 (see FIG. 2) via a link mechanism (not shown).

The air conditioner control device 6 incorporates a microcomputer (not shown) in which a control program and various arithmetic expressions related to air condition control are stored. As shown in FIG. 2, an air conditioner operation panel 33 (FIG. ) On the basis of the operation signal output from the servo motor 13 and the detection signals from various sensors (described later).
Control signals are output to a motor drive circuit 34 for driving the blower motor 3c and a clutch drive circuit 35 for driving the electromagnetic clutch 25.

The above-mentioned various sensors include an inside air temperature sensor 36 for detecting a vehicle interior temperature (inside air temperature Tr), an outside air temperature sensor 37 for detecting an outside air temperature (outside air temperature Tam), and a solar radiation amount (solar radiation amount Ts). A solar sensor 38, an air temperature sensor 39 (evaporator temperature detecting means) for detecting an air temperature (evaporated temperature Te) immediately after passing through the refrigerant evaporator 22, and a temperature (cooling water temperature Tw) of the engine cooling water. Water temperature sensor 40,
And a humidity sensor 41 for detecting the relative humidity (humidity Rh) in the passenger compartment.

The air-conditioner operation panel 33 is disposed on an instrument panel (not shown) in the vehicle compartment, and as shown in FIG. 3, a temperature setting switch 42 for setting a desired interior temperature of the occupant, and this temperature setting switch 42. A set temperature display section 43 for digitally displaying the temperature set in the above, an auto switch 44 for outputting an automatic control command for the air conditioner 1, an off switch 45 for outputting an operation stop command for the air conditioner 1,
Inside / outside air changeover switch 46 for selecting the inlet mode, outlet changeover switch 47 for selecting the outlet mode, blower 3
And an air conditioner switch 49 for selecting ON / OFF of the electromagnetic clutch 25 are provided.

Next, the operation of the vehicle air conditioner will be described. FIG. 4 is a flowchart showing a processing procedure of the microcomputer provided in the air conditioner control device 6. First, in step S1, various counters and flags are initialized, and constants are set.

Subsequently, at step S2, the set temperature signal Tset of the temperature setting switch 42 is read, and at step S3, the detection signals (T
r, Tam, Ts, Te, Tw, Rh). Subsequently, in step S4, a target outlet temperature in the vehicle compartment (hereinafter, referred to as TAO) is calculated according to the following equation 1 (target outlet temperature calculation function).

[0024]

[Equation 1] TAO = Kset · Tset−Kr · Tr−Kam ·
Tam-Ks ・ Ts-KRh ・ Rh + C Kset: temperature setting gain Kr: inside air temperature gain Kam: outside air temperature gain Ks: solar radiation gain KRh: humidity gain C: correction constant

Subsequently, in steps S5 to S7, based on the TAO calculated in step S4, the blower voltage, the inlet mode, and the outlet mode are determined from the characteristic diagrams shown in FIGS. 5 to 7, respectively. FIG. 5 to FIG.
Are stored in the microcomputer of the air conditioner control device 6 in advance. Subsequently, in step S8, the target opening SW of the air mix damper 31 is calculated according to the following equation 2 so that the actual blown air temperature into the vehicle compartment becomes the TAO calculated in step S4 (target opening). Arithmetic function).

[0026]

## EQU2 ## SW = [(TAO-Te) / (Tw-Te)]
× 100 (%) Subsequently, in step S9, the operation of the refrigerant compressor 18 is determined. The operation determination of the refrigerant compressor 18 is performed based on each determination condition for securing the capacity necessary for air conditioning in the vehicle interior, comfort with respect to humidity, and anti-fogging property due to humidity.

The operation of the refrigerant compressor 18 will now be described with reference to the flowchart shown in FIG. First, in step 901, it is determined whether or not it is necessary to turn on the refrigerant compressor 18 in order to secure the capacity required for air conditioning in the vehicle cabin based on the characteristic diagram shown in FIG. Note that FIG.
The horizontal axis of the characteristic diagram shown in FIG.
This is the difference between O and the temperature of the introduced air introduced into the duct 2 (suction temperature Tin). Α on the horizontal axis is the temperature rise of the introduced air in the duct 2, and is a constant or a function of the vehicle speed. The suction temperature Tin may be detected using a sensor, or may be estimated from the suction port mode, the outside temperature Tam, the inside temperature Tr, and the like.

If it is determined in step 901 that the refrigerant compressor is to be turned on, the process proceeds to step 902, where an ON mode for turning on the refrigerant compressor 18 is set.
Next, a description will be given of a process of determining whether or not the interior of the vehicle is fogged when the refrigerant compressor 18 is turned off. When it is determined in step 901 that the refrigerant compressor 18 is turned off, that is, when TAO is sufficiently higher than the suction temperature Tin, the process proceeds to step 903 and the relative humidity Rh in the vehicle cabin detected by the humidity sensor 41.
Then, the absolute humidity Hr in the vehicle interior is calculated from the internal temperature Tr detected by the internal temperature sensor 36 (absolute humidity calculation function).

Subsequently, in step 904, the window glass 10 is set on the basis of the outside air temperature read from the outside air temperature sensor 37.
An inner surface dew point temperature Tg is calculated. Note that the dew point temperature Tg of the window glass 10 is expressed by the following equation (3):
It is expressed as a function of m and vehicle speed V. Here, it is simply set as the outside temperature Tam.

[0030]

## EQU3 ## Tg = f (Tr, Tam, V) Subsequently, in step 905, as an anti-fog determination value for determining whether the window glass 10 is fogged or not, FIG.
The saturation absolute humidity Hw is calculated from the dew point temperature Tg of the inner surface of the window glass 10 calculated in step 904 by using a psychrometric chart (previously stored in the microcomputer) shown in FIG.

Subsequently, in step 906, the vehicle interior absolute humidity Hr calculated in step 903 and the saturation absolute humidity H as the anti-fog determination value calculated in step 905 are calculated.
and w (the anti-fogging determination function) to determine whether the window glass 10 is fogged or not. In this determination, (Hr-Hw)
If ≧ β (determination of YES), it is necessary to turn on the refrigerant compressor 18 because the window glass 10 is fogged.
Go to 02.

On the other hand, in the determination of step 906, (Hr−
If (Hw) <β (determination of NO), the process proceeds to step 907, where the vehicle interior humidity Rh (the value detected by the humidity sensor 41) is set to the upper limit value γ of the comfortable humidity (for example, the vehicle interior temperature 25 ° C. and the relative humidity 60 %). In this determination, when Rh ≧ γ (determination of YES), the degree to which the occupant feels uncomfortable is high, so the refrigerant compressor 18 is turned on.
And the process proceeds to step 902.

If it is determined in step 907 that Rh <γ (NO), the flow advances to step 908 to determine whether or not the refrigerant compressor 18 has just been turned off. In this determination, immediately after the refrigerant compressor 18 is turned off (YES
The determination proceeds to step 912, in which the value Rh obtained by converting the humidity sensor value immediately before the refrigerant compressor 18 is turned off to 25 ° C. is stored in the memory Mh, and the refrigerant compressor 18
Time A elapsed since was turned off (for example, 10 seconds)
Starts counting by the timer that counts.

Thereafter, the routine proceeds to step 909, where it is determined whether or not the timer has timed out (for example, 10 seconds have elapsed).
Proceed to 10. In step 910, the amount of change in the vehicle interior humidity (Rh−10) until the timer expires (10 seconds).
Mh) is greater than or equal to a predetermined value K1. In other words, depending on whether or not the amount of change in the humidity inside the vehicle from when the refrigerant compressor 18 is turned off to when the predetermined time has elapsed is large, it adheres to the refrigerant evaporator 22 and re-evaporates the water vapor.
It is determined whether the window glass 10 is fogged.

The determination in step 910 is (Rh-Mh)
If ≧ K1 (determination of YES), the routine proceeds to step 902, where the refrigerant compressor 18 is set to the ON mode. On the other hand, when the determination in step 910 is (Rh−Mh) <K1 (NO
The determination proceeds to step 911, where the refrigerant compressor 18 is set to the OFF mode. Then, the process proceeds to step S10,
Servo motors 13, 17, 32, motor drive circuit 34,
A control signal is output to the clutch drive circuit 35 to control the blower outlet switching dampers 11 and 12, the inside / outside air switching damper 16, the air mix damper 31, the blower motor 3c, and the electromagnetic clutch 25 (control function), thereby controlling the refrigerant compressor. Activate 18.

Thus, the air passing through the refrigerant evaporator 22 is dehumidified and cooled, and the fogging of the window glass 10 can be prevented. Subsequently, in step S11, it is determined whether or not a predetermined control cycle τ has elapsed.
S) repeats the processing of step S2 and subsequent steps. If the processing has not elapsed (NO determination), a predetermined control cycle τ
Step S11 is repeated until elapses.

As described above, in the antifogging judgment in step 906, it is judged that the window glass 10 is not fogged, and the refrigerant compressor 18
Even if the operation is stopped, when the amount of humidity change for a predetermined time after the stop is large, fogging of the window glass is highly likely to occur, so the refrigerant compressor 18 is operated to prevent fogging of the window glass 10. be able to. In addition, the humidity inside the vehicle after the operation of the refrigerant compressor 18 is stopped is sampled at predetermined time intervals, a change rate of the sampled data is calculated, the change rate is compared with a predetermined value, and based on the comparison result, Alternatively, the refrigerant compressor 18 may be operated.

Next, another embodiment of the vehicle air conditioner according to the present invention will be described. FIG. 11 is a flowchart showing the operation. In the vehicle air conditioner according to the present embodiment, in the operation determination of the refrigerant compressor 18 (step S9), when the refrigerant compressor 18 stops, a maximum value of a predetermined time after the stop is compared with a predetermined value, and the comparison is performed. The purpose is to prevent the fogging of the window glass 10 by operating the refrigerant compressor 18 based on the result. In the flowchart of FIG. 11, the same processes as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In step 908, the refrigerant compressor 18
It is determined whether or not the operation has just stopped, and if it has just stopped (determination of YES), the process proceeds to step 913, and
A timer (for example, 20 seconds) for counting a time for detecting the maximum value of the humidity in the vehicle is started. Then, the process proceeds to a step 914, wherein a rising peak value Pr of the in-vehicle humidity is detected. Specifically, the humidity sensor value immediately before turning off the refrigerant compressor 18 is stored in the memory M1 and the memory M2,
The current humidity sensor value (converted to 25 ° C.) is compared with the value in the memory M2, and the larger value is sequentially updated in the memory M2. Then, the difference between the memories M2 and M1 is calculated to calculate the humidity rise peak value Pr.

Next, the routine proceeds to step 915, where it is determined whether or not the timer has expired. If the timer has expired (determination of YES), the routine proceeds to step 916, where the in-vehicle humidity rise peak detected in step 914 is detected. It is determined whether the value Pr is equal to or greater than a predetermined value K2. If it is equal to or greater than the predetermined value K2 (determination of YES), the routine proceeds to step 902, where the refrigerant compressor 18 is set to the ON mode. On the other hand, if it is not equal to or greater than the predetermined value K2 (determination of NO), the routine proceeds to step 911, where the refrigerant compressor 18 is turned off.
Set to F mode.

As described above, when the refrigerant compressor 18 is turned off, the off state is maintained for a predetermined time, and it is determined again whether or not the window glass is fogged based on the magnitude of the rising peak value Pr of the humidity in the vehicle during that time. By operating the refrigerant compressor 18 based on the determination result, fogging of the window glass can be prevented. In each of the above embodiments, Step 906 is performed by the anti-fogging means, and Steps 902 and 907 to
912 (steps 902, 907, 908, 911, 9
13 to 916) correspond to the reactivation means, respectively.

In each of the above embodiments, the present invention is applied to the air-mix type air conditioner 1, but the amount of cooling water supplied to the heater core 28 is controlled according to the opening degree of the flow control valve provided in the hot water circuit 5. May be applied to a reheat type air conditioner. The flow control valve can adjust the valve opening by, for example, duty ratio control. Further, in each of the above-described embodiments, E refrigerant is provided between the refrigerant evaporator 22 and the refrigerant compressor 18.
Although the EPR type refrigeration cycle 4 equipped with the PR 23 was used, the refrigerant compressor 18 was turned ON / OFF via the electromagnetic clutch 25.
A refrigeration cycle that performs OFF control, a variable displacement refrigeration cycle including a variable displacement refrigerant compressor, or the like may be employed.

Further, in each of the above embodiments, the humidity sensor 4
1 and the detected value of the inside air sensor 36, the absolute humidity Hr
Was calculated, but the relative humidity R detected by the humidity sensor 41 was
Control may be performed by converting h into a relative humidity at a fixed temperature (for example, 25 ° C.). Further, in each of the above embodiments, the air temperature immediately after passing through the refrigerant evaporator 22 (post-evaporation temperature Te) detected by the post-evaporation temperature sensor 39 is used as the temperature of the refrigerant evaporator 22. Alternatively, a value obtained by detecting the fin temperature 22 or the low pressure of the refrigeration cycle 4 and estimating the post-evaporation temperature may be used.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a vehicle air conditioner according to the present invention.

FIG. 2 is a block diagram of a drive system connected to the air conditioner control device 6.

FIG. 3 is an explanatory front view of an air conditioner operation panel 33.

FIG. 4 is a flowchart showing a processing procedure of the air conditioner control device 6.

FIG. 5 is a characteristic diagram showing a relationship between a blower voltage and a TAO.

FIG. 6 is a characteristic diagram showing switching of a suction port mode for TAO.

FIG. 7 is a characteristic diagram showing switching of the outlet mode for TAO.

FIG. 8 is a flowchart for determining whether to operate the refrigerant compressor 18 based on the amount of change in the detection value of the humidity sensor immediately after the refrigerant compressor 18 is turned off.

FIG. 9 is a characteristic diagram showing an operation of the refrigerant compressor 18 with respect to TAO-Tin.

FIG. 10 is a characteristic diagram showing a relationship between Hw and Tam.

FIG. 11 is a flowchart for determining whether to operate the refrigerant compressor 18 based on the maximum value of the detection value of the humidity sensor after the refrigerant compressor 18 is turned off.

[Explanation of symbols]

1. Air conditioners for vehicles 2. Ducts 3. Blowers,
4. Refrigeration cycle, 5. Hot water circuit, 7. Defroster outlet, 10. Window glass, 15. Outside air inlet, 1
8. Refrigerant compressor, 19 Refrigerant condenser, 22 Refrigerant evaporator, 26 Engine for traveling, 28 Heater core, 31 Air mix damper.

Continuation of the front page (56) References JP-A-61-278418 (JP, A) JP-A-56-124509 (JP, A) JP-A-1-297318 (JP, A) JP-A-3-22960 (JP) , U) Actually open sho 64-22665 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60H 3/00 B60H 1/32 B60S 1/54

Claims (4)

(57) [Claims] 1. A refrigerant compressor and a refrigerant evaporator constituting a refrigeration cycle, and humidity detecting means for detecting humidity in a vehicle compartment, and operating the refrigerant compressor based on the detected humidity in the vehicle compartment. In the vehicle air conditioner configured to prevent fogging of the window glass of the vehicle, based on the detected change in humidity in the vehicle interior after the operation of the refrigerant compressor is stopped, the refrigerant compressor An air conditioner for a vehicle, comprising a re-actuating means for re-actuating the vehicle. 2. An anti-fogging determining means for comparing the detected humidity in the vehicle interior with a predetermined value to determine whether or not it is necessary to prevent the fogging, wherein If the result of the fogging determination is that there is no need for anti-fogging, the refrigerant compressor is restarted based on the detected change in humidity in the vehicle interior after the operation of the refrigerant compressor has stopped. The air conditioner for a vehicle according to claim 1, wherein the air conditioner is operated. 3. The vehicle air conditioner according to claim 1, wherein the change state is a change amount in a predetermined time. 4. The vehicle air conditioner according to claim 1, wherein the change state is a maximum value in a predetermined time.