JPH0698891B2 - Demist control device for automobile air conditioner - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demist control device used for clearing a window glass in an automobile air conditioner.

(Prior Art) As a so-called demist method for clearing the fogging of a window glass, a method of introducing outside air and a method of driving a compressor are well known. Japanese Patent Laid-Open No. 60-1019 discloses an automatic demist control device incorporating both of these. This is to control the inside / outside air switching door and the compressor according to the outside air temperature, and to introduce the outside air when the outside air temperature drops to a predetermined value.

(Problems to be solved by the invention) In such a cold environment where the outside air temperature is low, it is possible to remove fogging in most cases by introducing the outside air. In cold regions, however, spike tires are used to cut concrete on paved roads. There is dust pollution in which the dust is blown up. Therefore, in order to prevent the dust from entering the passenger compartment, it may be necessary to circulate the inside air. Therefore, in this case, even if the compressor is driven to dehumidify it with the evaporator, the temperature of the evaporator is usually set near freezing because the compressor is controlled to be turned on and off. There is a problem in that the remaining water that is not removed by the evaporator is condensed on the inner surface of the window glass due to contact with the window glass having a low temperature, and it becomes cloudy to hinder driving.

Therefore, it is an object of the present invention to provide a demist control device for an automobile air conditioner that can automatically and efficiently clear the windshield even when the inside air is circulated during cold weather as described above. I am trying.

(Means for Solving Problems) The present application is composed of four inventions. The first invention is, as shown in FIG. 1, a first judging means 201 for judging whether or not the inner surface of the window glass 23 is fogged, and whether or not the temperature of the window glass 23 is below a predetermined value. It is determined that the window glass 23 is fogged by the second determination means 202 that determines whether or not it is, the third determination means 203 that determines whether the internal air circulation is performed, and the first determination means 201. If the second determination means 202 determines that the temperature of the window glass 23 is less than or equal to a predetermined value and the third determination means 203 determines that the inside air circulation is established, the evaporator 10 freezes. It has a compressor control means 300 for driving the compressor 11 until the temperature becomes lower than the temperature.

In addition, the second invention, as shown in FIG.
A humidity sensor 36 for detecting the relative humidity in the vicinity of is provided, and the first determining means 201 determines whether or not the inner surface of the window glass 23 is fogged based on the output of the humidity sensor 36. Unlike the first invention, the other points are the same. In the second aspect of the invention, the compressor control means 300
Can control the compressor 11 so as to lower the on / off temperature of the compressor 11 as the relative humidity near the window glass 23 detected by the humidity sensor 36 increases.

In addition, the third invention, as shown in FIG.
Temperature sensors 31 and 35 for detecting the temperature associated with the temperature sensor 31 and 35 are provided, and the second determination means 202 is provided based on the outputs of the temperature sensors 31 and 35.
Different from the first invention in that it is determined whether or not the temperature of the window glass 23 is equal to or lower than a predetermined value, and the other points are the same. In the third aspect of the invention, the compressor control means 300 includes the window glass 23 detected by the temperature sensors 31 and 35.
The on-off temperature of the compressor 11 can be controlled to decrease as the temperature of the compressor 11 decreases.

Further, in the fourth explanation, as shown in FIG. 4, a fourth judging means 204 for judging whether or not the engine speed is equal to or lower than a predetermined value is added to the first invention. The fourth determining means 204 drives the evaporator 10 of the compressor 11 to a temperature below the freezing temperature when the engine speed is below a predetermined value.

(Operation) Therefore, in any of the inventions, when the inside air circulation mode is set in the cold state, the temperature of the evaporator 10 is frozen by the compressor control means 300 according to the determination results of the first to third determination means 201 to 203. Since the compressor 11 is driven until the temperature becomes equal to or lower than the temperature, it is possible to sufficiently dehumidify the air passing through the evaporator 10 even if it contacts the window glass 23 without dew condensation, and therefore, it is possible to achieve the above object. It is possible.

(Example) FIG. 5 shows a first example according to the present invention.
The automobile air conditioner comprises a blower unit 1, a cooling unit 2 and a heater unit 3. The blower unit 1 is formed in a blower case 4 in such a manner that an inside air inlet 5 and an outside air inlet 6 are bifurcated, and an inside / outside air switching door 7 is provided in the divided portion, and the inside / outside air switching door 7 circulates the inside air. A choice is made as to whether to introduce air or outside air. The blower 8 includes a motor 8a and a fan 8b rotated by the motor 8a.
This fan 8b is housed in the blower case 4, and the rotation speed of the fan 8b can be switched according to the energization of the motor 8a.

The cooling unit 2 has a cooling case 9 whose one end is connected to the blower case 4, and an evaporator 10 is housed in the cooling case 9. The evaporator 10, together with the compressor 11, the condenser 12, the liquid tank 13 and the expansion valve 14, is pipe-connected to form a cooling cycle. The compressor 11 is
An electromagnetic clutch 15 is provided, and by connecting and disconnecting electricity to the electromagnetic clutch 15, an engine (not shown) is connected and disconnected.

The heater unit 3 has a heater case 16 whose one end is connected to the cooling case 9.
A heater core 17 is housed inside. This heater core 17
The cooling water from the engine circulates in the. Further, an air-mix door 18 is provided in front of the heater core 17, and the heater core is changed according to the opening of the air-mix door 18.
The ratio of the air sent to 17 and the air bypassing the heater core 17 is determined, and the air is mixed behind the heater core 17 and the temperature thereof is adjusted. A defrost outlet 19, a vent outlet 20, and a heat outlet 21 are formed at the other end of the heater case 16, and a mode door for selectively opening and closing them.
22a and 22b are provided. Above defrost outlet 19
Is opened so that blown air is blown out along the window glass 23 on the front side of the automobile.

The inside / outside air switching door 7 is connected to the actuator 41 and can be moved by the actuator 41. The actuator 41, the motor 8a of the blower 8 and the electromagnetic clutch 15 of the compressor 11 are energized according to control signals from the micro computer 27 via the actuator drive circuit 24, the blower drive circuit 25 and the clutch drive circuit 26, respectively. Controlled.

The microcomputer 27 is a known one having a central processing unit CPU, a read only memory ROM, a random access memory RAM and the like. An A / D converter 29 is connected to the microcomputer 27 via a multiplexer 28.
This A / D converter 29 is provided on the inner surface of the window glass 22 for detecting the temperature of the window glass 22 and the evaporator sensor 30 which is inserted into the evaporator 10 and detects the temperature of the evaporator 10. The window glass temperature sensor 31 is connected, and the analog signals from the evaporator sensor 30 and the window glass temperature sensor 31 are converted into digital signals by the A / D converter 29, selected by the multiplexer 28 and input to the micro computer 27. To be done. In addition, the micro computer 27 automatically blows out the blower switch 32 for setting the speed of the blower 8, the intake switch 33 for setting the position of the inside / outside air switching door 7, and the inside of the window glass 22 when fogging occurs. Alternatively, an air conditioner switch or demist switch 34, which is operated by a passenger and turned on, is connected.

FIG. 6 shows an example of control operation of the microcomputer. The microcomputer starts operation from step 100, resets and initializes the contents of RAM in the next step 101, and proceeds to the next step 102. . In this step 102, it is determined whether or not the demist switch is on based on the signal from the demist switch described above. If the demist switch is not on, there is no need to control the demist, so the process waits until the demist switch is turned on. If it is determined that the demist switch is on, the routine proceeds to the next step 103.

In this step 103, it is determined whether or not the window glass temperature Tg detected by the window glass temperature sensor described above is higher than a predetermined value. For example, the temperature Tg of the window glass is 5
If the temperature goes below ℃, it is judged as "low", and if it goes over 10 ℃, it is judged as "high". And this step 103
If it is determined to be “high” by, the process proceeds to step 106, where the temperature of the evaporator is near the freezing temperature, for example, the off point is 1
The on / off control is performed while comparing the compressor with the output from the evaporator sensor described above so that the on-point becomes 3 ° C. On the other hand, if it is determined to be "low" in step 103, the process proceeds to step 104.

In this step 104, it is determined whether the inside / outside air switching door is in the inside air circulation (RECIRC) mode in which the inside air is opened based on the output from the intake switch. If it is determined that it is not the internal air circulation, that is, it is the outside air introduction mode, the process proceeds to step 106, but if it is determined that the internal air circulation is performed, the process proceeds to step 105. In this step 105, the compressor is on / off controlled so that the evaporator is turned off at a temperature lower than the freezing temperature, for example, -10 ° C and turned on at -8 ° C. However,
As shown in FIG. 7, the on / off temperature of the compressor may be continuously decreased as the window glass inner surface temperature Tg detected by the window glass temperature sensor described above decreases. It is also possible to control in a stepwise manner. When the processes of steps 105 and 106 are completed, step 107
Then, in step 107, the blower is controlled so that the blower is rotated at a low speed even when the blower switch is off, and when the process of step 107 is completed, the process returns to step 102.

Therefore, the inner surface of the window glass 23 becomes cloudy and
If the inner surface temperature of 23 is low and it is in the internal air circulation mode, the process of step 105 is performed and the evaporator 1
Since the temperature of 0 drops below the freezing temperature, the air passing through the evaporator 10 is sufficiently dehumidified.

In this case, if the temperature of the evaporator 10 remains below the freezing temperature for a long time, the refrigerant that has not sufficiently evaporated is sucked into the compressor 11 and a so-called liquid back problem occurs, but the clutch drive circuit 26 described above has a compressor. A temperature switch that is turned off when the suction refrigerant temperature of 11 is lowered, and if there is a risk of liquid backing, the compressor 11 can be stopped to deal with it.

In FIG. 8 a second embodiment according to the invention is shown,
In the second embodiment, an outside air temperature sensor 35 for detecting the outside air temperature is provided in place of the window glass temperature sensor 31 in the first embodiment described above, and the demist switch 34 in the first embodiment is used. Instead, a humidity sensor 36 is provided. The humidity sensor 36 is provided on the inner surface of the window glass 23 and detects the relative humidity near the inner surface of the window glass.

FIG. 9 shows an example of control operation of the microcomputer 27 in the second embodiment. Instead of the steps 102, 103 in the first embodiment, the steps 108, 109 are shown.
Is inserted. In step 108, it is determined whether or not the window glass is fogged depending on whether or not the relative humidity ηg near the inner surface of the window glass detected by the above-mentioned humidity sensor is larger than a predetermined value. That is, the relative humidity ηg
If, for example, it is determined that it is lower than 90%, the process proceeds to step 109, and if it is determined that it is lower than 80%, the process proceeds to step 106. In step 109, the outside air temperature detected by the outside air temperature sensor described above.
It is determined whether Ta is higher than a predetermined value. For example, if it is determined that the temperature is higher than 0 ° C, the process proceeds to step 109, and if it is determined that the temperature is lower than -5 ° C, the process proceeds to step 106. It is something to proceed. Since the outside air temperature Ta correlates with the temperature of the inner surface of the window glass, the same operation and effect as those of the first embodiment can be obtained. Of course, the window crow outside temperature can be used instead of the window glass inside temperature and outside air temperature.

FIG. 10 shows another example of the control operation of the microcomputer in the above embodiment, in which the contents of the processing of step 108 are incorporated in step 105 '. That is, in step 105 ', as shown in FIG. 11, when the humidity .eta.g near the inner surface of the window glass detected by the humidity sensor rises, for example, more than 80%, the compressor is turned on and off according to the rise. It is designed to lower the temperature.

Incidentally, the same points as those in the first embodiment described above are designated by the same reference numerals in the drawings, and the description thereof is omitted.

In FIG. 12, a third embodiment of the present invention is shown, which in comparison with the first embodiment described above,
In order to detect the number of revolutions of the engine, a rotation sensor 38 composed of an electromagnetic pickup or the like is provided facing the pulsar 37 rotating with the engine, and a pulse signal generated by the rotation sensor 38 is input to the microcomputer 27. The difference lies in that an indicator 39 for giving a warning to the driver to reduce the engine speed and an indicator drive circuit 40 for driving the indicator 39 in response to a control signal from the microcomputer 27 are provided.

Then, as shown in FIG. 13, the processing of steps 110 to 112 is inserted in the microcomputer 27. The step 110 determines "low" when the engine speed Np detected by the rotation sensor 37 described above becomes, for example, 2000 rpm or less, and "high" when it rises to 5000 rpm or more.
To determine. Then, in this step 110, "low"
If it is determined that the above-mentioned step 105,
If it is determined to be “high”, go to steps 111 and 112,
The compressor is turned off and the above-mentioned display is turned on. As described above, when the engine speed is low, the on / off temperature of the compressor is lowered, while when the engine speed is high, stopping the compressor is performed when the engine speed is high. This is to prevent the valve body and the like from being destroyed due to the large suction force of the refrigerant and the liquid backing up of the refrigerant.

In the explanation of this third embodiment as well,
The same points as those of the embodiment are given the same numbers in the drawings and the description thereof is omitted.

(Effects of the Invention) As described above, according to the present invention, when the window glass is fogged in the internal air circulation mode during cold weather, the evaporator drives the compressor until the freezing temperature becomes lower than the freezing temperature. Therefore, the air passing through the evaporator can be further cooled and sufficiently dehumidified, and the window glass can be cleared. Further, by driving the compressor only when the engine speed is low, it is possible to prevent the refrigerant from being backed up in the compressor and to protect the compressor.

[Brief description of drawings]

FIG. 1 is a block diagram showing the first invention of the present application, FIG. 2 is a block diagram showing the second invention of the present application, FIG. 3 is a block diagram showing the third invention of the present application, and FIG. 5 is a block diagram showing the invention of FIG.
FIG. 7 is a block diagram showing a first embodiment according to the present invention, FIG. 6 is a flow chart showing an example of control operation of a microcomputer used in the above embodiment, and FIG. 7 is control of a compressor in the above embodiment. FIG. 8 is a diagram showing the characteristics, FIG. 8 is a configuration diagram showing a second embodiment according to the present invention, FIG. 9 is a flow chart showing an example of control operation of the microcomputer used in the above embodiment, and FIG. FIG. 11 is a flow chart showing another control operation example of the above, FIG. 11 is a diagram showing a compressor control characteristic in the above embodiment, FIG. 12 is a configuration diagram showing a third embodiment of the present invention, FIG. 3 is a flow chart showing an example of control operation of the microcomputer used in the above-mentioned embodiment. 10 ... Evaporator, 11 ... Complexor, 23 ... Window glass, 31 ... Window glass temperature sensor, 35 ... Outside air temperature sensor, 36 ... Humidity sensor, 201 ... First judging means, 202 ...
... second judging means 203 ... third judging means 204 ... fourth judging means 300 ... compressor control means.

Claims (6)

[Claims] 1. A first determining means for determining whether or not fogging has occurred on the inner surface of the window glass, a second determining means for determining whether or not the temperature of the window glass is below a predetermined value, and the inside air. It is determined by the third determining means for determining whether or not it is in circulation and the first determining means that the window glass is fogged, and the second determining means determines the temperature of the window glass to be predetermined. And a compressor control means for driving the compressor until the evaporator temperature becomes lower than the freezing temperature when it is determined that the value is less than or equal to the value and when the third determination means determines that the inside air circulation is achieved. Demist control device for automobile air conditioners. 2. A humidity sensor for detecting relative humidity in the vicinity of the inner surface of the window glass, and a first judging means for judging whether or not the inner surface of the temperature glass is fogged according to the output of the humidity sensor. A second determination means for determining whether or not the temperature of the window glass is below a predetermined value, a third determination means for determining whether or not the inside air circulation is established, and the window by the first determination means. When it is determined that the glass is fogged, the temperature of the window glass is lower than or equal to a predetermined value by the second determination unit, and the inside air circulation is determined by the third determination unit. A demist control device for an air conditioner for an automobile, comprising: a compressor control means for driving the compressor until the evaporator becomes lower than a freezing temperature. 3. The on / off temperature of the compressor is gradually lowered in response to an increase in the relative humidity near the inner surface of the window glass detected by the humidity sensor, and the control means gradually lowers the temperature. A demist control device for an automobile air conditioner according to claim 1. 4. A first determining means for determining whether or not fogging has occurred on the inner surface of the window glass, a temperature sensor for detecting a temperature related to the temperature of the window glass, and an output of the temperature sensor. The second window by the first determining means, the second determining means for determining whether the temperature of the window glass is below a predetermined value, the third determining means for determining whether the internal air circulation is established or not. It is determined that the glass has fog, and the second
When the temperature of the window glass is determined to be equal to or lower than a predetermined value by the determining means and the inside air circulation is determined by the third determining means, the evaporator is driven until the evaporator temperature becomes lower than the freezing temperature. A demist control device for an automobile air conditioner, comprising a compressor control means. 5. The control means lowers the on / off temperature of the compressor in response to a decrease in temperature related to the temperature of the window glass detected by the temperature sensor. Demist control device for automobile air conditioners. 6. A first determining means for determining whether or not fogging has occurred on the inner surface of the window glass, a second determining means for determining whether or not the temperature of the window glass is below a predetermined value, and the inside air. Third determining means for determining whether or not it is in circulation, fourth determining means for determining whether or not the rotation speed of the engine for driving the compressor is equal to or lower than a predetermined value, and the first determining means. It is determined that the window glass is fogged by, the temperature of the window glass is determined to be a predetermined value or less by the second determination means, it is determined that the inside air circulation by the third determination means, An air conditioner for a vehicle, further comprising: a compressor control unit that drives the compressor until the evaporator temperature becomes lower than a freezing temperature when the fourth determination unit determines that the engine speed is equal to or lower than a predetermined value. Location of de-misting control device.