KR102545121B1 - Air conditioner for vehicle and method for controlling the same - Google Patents

Abstract

An air conditioner for a vehicle and a control method thereof are disclosed. The present invention compares the air conditioning usage time and the filter exchange time, and when it is determined that the air conditioning usage time is equal to or greater than the filter exchange time, the target temperature and the cutoff temperature of the evaporator are variably changed according to the number of stages of the blower until the air filter is replaced Provided is a vehicle air conditioner capable of improving the icing phenomenon of an evaporator that may occur due to dust accumulation in an air filter by controlling and a control method thereof.

Description

Vehicle air conditioner and its control method {AIR CONDITIONER FOR VEHICLE AND METHOD FOR CONTROLLING THE SAME}

The present invention relates to a vehicle air conditioner, and more particularly, to a vehicle air conditioner capable of improving an evaporator icing phenomenon that may occur due to dust accumulation in an air filter and a control method thereof.

In general, an air conditioner for a vehicle is a device that cools or heats the interior of a vehicle by introducing air inside/outside the vehicle, heating or cooling the air, and blowing the air into the interior of the vehicle.

1 is a schematic diagram showing an air conditioner equipped with a general air filter.

As shown in FIG. 1, the air conditioner for a vehicle has an internal/external air conversion door 11 installed therein so as to selectively open and close the internal/external air inlet formed on the inlet side according to the internal/external air mode, and the internal/external air A blowing unit 10 installed so that the blower 12 is driven by the motor 13 so that air sucked through the inlet 11 can be blown toward the air conditioning case, and the inside of the air conditioning case 15 at a predetermined interval. An evaporator 18 and a heater core 22, and a temperature control door 20 installed between the evaporator 18 and the heater core 22 to control the amount of air passing through the heater core 22; , A mode door 24 formed on the outlet side of the air conditioning case 15 to open and close a plurality of vents 26 communicating with the interior of the vehicle, and an air filter 14 installed on the upstream side of the blower 12 made up of

Therefore, when the user operates the control unit 30 to control the air conditioner, the control unit 28 adjusts the position of the indoor/outdoor conversion door 10 to select the indoor/outdoor mode, The motor of the blower is controlled to adjust the air volume, the position of the temperature control door 20 and the mode door 24 is adjusted, or the temperature and various air conditioning modes are performed.

That is, in the bet mode, the inside/outdoor conversion door 11 opens the outside air inlet and seals the outside air inlet, and at this time, the bet introduced through the inside inlet by the operation of the blower 12 filters the air filter 14. After air passes through and is blown into the air conditioning case 15, it is guided to each vent 26 while selectively passing through the heater core 22 by the temperature control door 20 and mode door 24 to cool the air. discharged indoors.

Also, in the outdoor air mode, on the contrary, the indoor air conversion door 11 closes the air inlet and opens the air inlet. At this time, the outdoor air introduced through the air inlet by the operation of the blower 12 ) and then blown into the air conditioning case 15, it is guided to each vent 26 while selectively passing through the heater core 22 by the temperature control door 20 and mode door 24. and is discharged into the cabin.

However, the air filter 14 installed in the air conditioner filters dust in the air to purify the air introduced through the inside and outside air inlets 11. When used for a long time, dust accumulates and passes through the air filter 14. The air resistance rapidly increases, pollutes the air, and also causes icing of the evaporator 18 to be described later, so it must be replaced at an appropriate time.

On the other hand, for example, in an air conditioner for a vehicle to which an external variable compressor or an electric compressor is applied, in order to prevent icing of the evaporator 18, the target temperature of the evaporator 18 is set to a lower limit according to the number of operating stages of the blower 12 under cooling conditions. are regulated At this time, if the outlet temperature of the evaporator 18 is lower than the target temperature, the refrigerant circulation is stopped. When the refrigerant circulation is stopped, since the air is not cooled in the evaporator 14, the evaporator outlet temperature gradually rises, and the evaporator outlet temperature rises. When the temperature rises above the limit temperature, the refrigerant circulation takes place again.

If the number of stages of the blower 12 is high, the amount of air passing through the evaporator 18 is large and heat exchange is active, so the target temperature of the evaporator 18 is low. Since heat exchange is poor due to a small amount of air passing through the evaporator, the icing phenomenon of the evaporator 18 is prevented by increasing the target temperature of the evaporator 18.

However, if dust is excessively accumulated on the air filter 14, even if the number of stages of the blower 12 is high, the air cannot pass through the air filter 14 and is not transferred to the evaporator 18, so that the evaporator 18 There was a problem that an icing phenomenon may occur.

In addition, in the prior art, even if a sensor for measuring the amount of dust actually accumulated in the air filter 14 is not provided for reasons of increased manufacturing cost or a sensor for measuring the amount of dust is provided, the exchange time is notified regardless of malfunction or dust amount, so accurate and accurate Replacing the air filter is difficult. Accordingly, there is a problem in that the probability that the icing phenomenon of the evaporator 18 may occur due to the delay in replacement of the air filter 14 increases.

Therefore, an object of the present invention to solve this problem is to compare the air conditioning use time and the filter exchange time and determine that the air conditioning use time is equal to or greater than the filter exchange time. An air conditioner for a vehicle capable of improving an evaporator icing phenomenon that may occur due to dust accumulation in an air filter by variably changing and controlling a target temperature and a cutoff temperature and a control method thereof.

The present invention in order to achieve the above object is an evaporator; a blower for blowing air sucked through the air inlet toward the evaporator; In the air conditioner for a vehicle including an air filter installed at least one of upstream and downstream of the blower and a control unit controlling the evaporator and blower, the control unit compares the air conditioning use time and the filter replacement time to determine the air conditioning use time If it is determined that the replacement time is equal to or greater than the replacement time, the target temperature and the cutoff temperature of the evaporator are variably changed and controlled according to the number of stages of the blower until the air filter is replaced, thereby preventing icing of the evaporator. .

In addition, the air conditioning use time is the cumulative use time for the blower or the cumulative time after shipment of the vehicle, and the control unit resets the air conditioning use time to 0 when it is determined that the air filter has been replaced, and the initial target temperature of the evaporator And it is possible to maintain the existing cooling performance by controlling the cutoff temperature.

In addition, a compressor driven by an engine to compress refrigerant and changing a discharge amount according to a cooling demand; a condenser condensing the refrigerant discharged from the compressor; an expansion valve that adiabatically expands the liquefied refrigerant passing through the condenser to form a mixture of gas and liquid, and whose opening is changed according to the amount of refrigerant discharged from the compressor; an evaporator that cools ambient air using latent heat of vaporization when the refrigerant is vaporized and then returns the refrigerant to the compressor; a blowing unit for blowing internal and external air to the evaporator; The outlet side of the evaporator may include an evaporator outlet temperature sensor for detecting air temperature and a control unit for controlling the target temperature and cutoff temperature of the evaporator according to the evaporator outlet temperature input from the evaporator outlet temperature sensor, air conditioning use time, and filter replacement time. can

In addition, when the control unit determines that the outlet temperature of the evaporator is lower than the target temperature of the evaporator, the control unit variably adjusts the number of rotations of the compressor based on the changed target temperature and cutoff temperature of the evaporator, or the pressure of the refrigerant discharged to the condenser and the expansion valve. It is possible to prevent the temperature of the evaporator from falling by variably controlling the amount of the refrigerant or by introducing outside air when the temperature of the outside air is higher than the temperature of the indoor air.

In addition, the cutoff temperature of the evaporator is set to a temperature lower than the target temperature of the evaporator, and the control unit, when determining that the outlet temperature of the evaporator is lower than the cutoff temperature, stops the operation of the compressor so that the temperature of the evaporator decreases that can be prevented

In addition, when the control unit compares the air conditioning use time and the filter exchange time and determines that the air conditioning use time is equal to or greater than the filter exchange time, the target temperature or the cutoff temperature of the evaporator may be equalized or lowered according to the increase in the number of stages of the blower. there is.

In addition, a display unit connected to the control unit may be further included so that the operator can check the air conditioning use time or correct the filter replacement time.

In order to achieve the above object, the present invention provides a measuring step of measuring an air conditioning use time by a control unit; A comparison step of comparing the measured air conditioning usage time and filter exchange time by the control unit, and if the control unit determines that the air conditioning use time is equal to or greater than the filter exchange time in the comparison step, the target temperature of the evaporator and the target temperature of the evaporator are determined according to the number of blowers Provided is a control method of a vehicle air conditioner including a changing step of variably changing the cutoff temperature.

In addition, in the comparison step, if it is determined that the air conditioning use time is shorter than the filter exchange time, the air conditioner may be controlled by changing the existing evaporator target temperature and cutoff temperature.

The method may further include a determination step of determining whether the air filter should be replaced, and in the comparison step, it is determined by the control unit that the air conditioning usage time is equal to or greater than the filter exchange time, and the air filter is determined to be replaced. Then, a changing step of variably changing the target temperature and the cutoff temperature of the evaporator may be performed.

The method may further include determining whether the air filter is to be replaced, and in the determining step, if the control unit determines that the air filter is to be replaced, the air conditioning use time may be reset to zero.

In addition, the air conditioning use time may be an accumulated use time for the blower or an accumulated time after leaving the vehicle.

Further, the control unit variably controls the number of revolutions of the compressor based on the target temperature and cutoff temperature of the evaporator changed in the changing step, variably controls the pressure and amount of refrigerant discharged to the condenser and the expansion valve, or changes the temperature of the outside air. When the temperature of the evaporator is higher than the indoor air temperature, it is possible to prevent the temperature of the evaporator from decreasing by introducing outside air.

According to the vehicle air conditioner and control method thereof described above, it is possible to improve the icing phenomenon of the evaporator that may occur due to the accumulation of dust in the air filter, and in particular, recently in countries such as China and India, or in Korea, a lot of dust There is an effect of reducing the arcing phenomenon that may occur in the evaporator in the air conditioner of a vehicle driving in a specific area where the arcing occurs.

1 is a schematic diagram showing an air conditioner equipped with a general air filter.
2 is a schematic diagram showing an air conditioner for a vehicle according to the present invention.
3 to 5 are flowcharts illustrating a control method of an air conditioner for a vehicle according to the present invention.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the examples described in detail below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes of elements in the drawings may be exaggerated to emphasize a clearer explanation. It should be noted that in each drawing, the same members are sometimes indicated by the same reference numerals. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention are omitted.

2 is a schematic diagram showing an air conditioner for a vehicle according to the present invention.

It is difficult to know how much dust is accumulated in the air filter 152 even if visually checked by non-experts. In addition, excessive dust has recently been generated in China, India, including Korea, and in certain areas where a lot of dust is generated, and when dust accumulates excessively on the air filter 152, icing may occur in the evaporator 140. The odds of being there increase considerably.

Therefore, as shown in FIG. 2 , the vehicle air conditioner according to the present invention is characterized in that it improves the icing phenomenon of the evaporator 140 that may occur when dust accumulates on the air filter 152 . In detail, the control unit 200 compares the air conditioning usage time T1 and the filter exchange time T2 and determines that the air conditioning usage time T1 is equal to or greater than the filter exchange time T2, and the air filter 152 is replaced. It is characterized in that the target temperature and the cutoff temperature of the evaporator 140 are variably changed and controlled according to the number of stages of the blower 153 until

Meanwhile, the air conditioning use time T1 described in the present invention is the cumulative use time of the blower 153 of the blowing unit 150 or the accumulated time after the vehicle is shipped, and is calculated by the control unit 200. At this time, if it is determined that the air filter 152 has been replaced, the controller 200 resets the air conditioning usage time T1 to 0, and proceeds with the calculation by accumulating the air conditioning usage time T1 from 0 again. In addition, the filter exchange time T2 may be fixed to approximately 2 to 3 years, and is a fixed time when the vehicle is shipped, but the value may be arbitrarily changed depending on the filter capacity of the air filter 152, the size of the vehicle, etc. can

Accordingly, it is possible to improve the icing phenomenon of the evaporator 140 that may occur due to the accumulation of dust in the air filter 152. There is an effect of reducing the arcing phenomenon that may occur in the evaporator in the air conditioner of the.

Hereinafter, an air conditioner for a vehicle according to the present invention will be described based on FIG. 2 .

As shown in Figure 2, the vehicle air conditioner according to the present invention is driven by the engine 100 to compress the refrigerant and the compressor 110, the discharge amount of which is changed according to the cooling demand; a condenser 120 condensing the refrigerant discharged from the compressor 110; An expansion valve 130 that adiabatically expands the liquefied refrigerant passing through the condenser 120 to form a mixture of gas and liquid, and whose opening is changed according to the amount of refrigerant discharged from the compressor 110; an evaporator 140 that returns the refrigerant to the compressor 110 after cooling ambient air using latent heat of vaporization when the refrigerant is vaporized; a blowing unit (150) for blowing internal and external air to the evaporator (140); On the outlet side of the evaporator 140, the evaporator outlet temperature sensor 210 for detecting air temperature and the evaporator outlet temperature input from the evaporator outlet temperature sensor 210, the air conditioning usage time T1, and the filter exchange time T2 are used according to It includes a control unit 200 that controls the target temperature and cutoff temperature of the evaporator 140 .

In addition, the blower unit 150 is formed on the inlet side of the air inlet through which internal or external air is introduced; A blower 153 for blowing the air sucked through the air inlet toward the evaporator 140; It includes a motor 154 driven in conjunction with the blower 153 and an air filter 152 installed at the front end of the blower 153 to filter air introduced from the indoor and outdoor air inlets.

At this time, the air conditioning use time (T1) is set to 0 when the vehicle is initially shipped, and the time is accumulated after the vehicle is shipped by the control unit 200 or the blower 153 of the blowing unit 150 is set to 0 by the motor 154 ) to accumulate when driven. In addition, when the controller 200 determines that the air filter 152 has been replaced, the air conditioning usage time T1 is reset to 0, and the air conditioning usage time T1 is accumulated again from 0 and proceeds with the calculation.

The filter replacement time T2 may be fixed to 2 to 3 years, for example, and this is not a fixed amount, and various variables exist depending on the vehicle type, a dusty environment, the filter capacity of the air filter 152, Depending on the size of the vehicle, etc., it can be changed by the operator at the most reasonable time through multiple tests.

In the control unit 200, the air conditioning usage time T1 continuously increases after the vehicle is shipped, or when the blower 153 is operated by the air conditioner or heater operation by the vehicle occupant, the air conditioning usage time T1 increases can do At this time, the control unit 200 compares the increased air conditioning use time T1 and the fixed filter exchange time T2 and determines that the air conditioning use time T1 is equal to or greater than the filter exchange time T2, the blower ( 153), the target temperature and the cutoff temperature of the evaporator 140 are variably changed and controlled.

Here, the target temperature of the evaporator 140 is a primary target temperature for preventing icing of the evaporator 140, and the controller 200 determines that the outlet temperature measured by the evaporator outlet temperature sensor 210 is lower than the target temperature. If, for example, the control unit 200 variably controls the number of revolutions of the compressor 110, variably controls the pressure and amount of refrigerant discharged to the condenser 120 and the expansion valve 130, or changes the temperature of the outside air to the indoor When the temperature of the evaporator 140 is higher than that of the air, the temperature of the evaporator 140 is prevented from decreasing by introducing external air.

In addition, the cutoff temperature of the evaporator 140 is set to a temperature lower than the target temperature of the evaporator 140, and is a secondary target temperature for preventing the icing phenomenon of the evaporator 140, and the controller 200 controls the evaporator outlet temperature. When it is determined that the outlet temperature measured by the sensor 210 is lower than the cutoff temperature, the clutch 220 is turned off to stop the operation of the compressor 110. This is to prevent water vapor contained in the air from being frozen in a condensed state in the evaporator 140 and impeding heat exchange. Accordingly, the refrigerant circulation is stopped, and when the refrigerant circulation is stopped, the air is not cooled in the evaporator 140, so the evaporator outlet temperature gradually rises, and when the evaporator outlet temperature rises above the limit temperature, the clutch 220 It is connected and the compressor 110 is operated again. For example, conventionally, the icing phenomenon of the evaporator 140 was prevented by setting the cutoff temperature of the evaporator 140 to 0.6 degrees.

On the other hand, the air filter 152 accumulates dust over time and cannot flexibly introduce air into the air inlet even with the operation of the blower 153, so the air volume passing through the evaporator 140 is reduced. When this is done, sufficient heat exchange between the air and the evaporator 140 is not achieved, and the temperature of the evaporator 140 further drops, resulting in an icing phenomenon. is not discharged.

That is, when a lot of dust accumulates on the air filter 152, even if the number of stages of the blower 153 is 8, the icing phenomenon of the evaporator 140 causes an air volume lower than that of the first stage to the occupant, causing discomfort. Since heat exchange in the evaporator 140 is not sufficiently performed, the icing phenomenon will become more serious.

Therefore, the controller 200 compares the air conditioning usage time T1 and the filter exchange time T2 and determines that the air conditioning usage time T1 is equal to or greater than the filter exchange time T2, and the air filter 152 is replaced. The target temperature and the cutoff temperature of the initial evaporator 140 are changed to a variable target temperature according to the number of stages of the blower 153 until control is performed.

[Table 1] below is a table showing the target temperature of the evaporator 140 varied according to the target temperature of the initial evaporator 140 and the number of stages of the blower 153.

blower single initial target temperature Variable target temperature 3 4℃ 5℃ 4 3.5℃ 4.5℃ 6 2.5℃ 4℃ 7 2℃ 4℃

[Table 2] below is a table showing the cut-off temperature of the evaporator 140 varied according to the cut-off temperature of the initial evaporator 140 and the number of stages of the blower 153.

blower single initial cutoff temperature Variable cutoff temperature 1 to 4 steps 0.6℃ 1.9℃ 5 to 6 steps 0.6℃ 1.5℃ 7 to 8 steps 0.6℃ 1.0℃

As can be seen from [Table 1] and [Table 2], it can be seen that the varied target temperature and cutoff temperature are higher than the initial target temperature and cutoff temperature.

That is, in the vehicle air conditioner according to the present invention, the control unit 200 compares the air conditioning use time T1 and the filter exchange time T2 and determines that the filter exchange time has exceeded the air filter 152 at a predetermined value. In anticipation of a decrease in air volume due to accumulation of dust, control is performed by changing the initial target temperature and cutoff temperature of the evaporator 140 to a variable cutoff temperature having a relatively high temperature. In this way, when the controller 200 changes the temperature to a variable cutoff temperature that is relatively high and controls the temperature, the refrigerant pressure and amount of refrigerant discharged to the condenser 120 and the expansion valve 130 in advance before the icing phenomenon of the evaporator 140 occurs. Since it is possible to variably control or stop the operation of the compressor 110, there is an effect of improving the icing phenomenon of the evaporator 140.

In this case, the change of the cut-off temperature of the evaporator 140 by the control unit 200 can be made in the form of a gradual temperature drop according to the increase in the number of stages of the blower 153, and it is preferable to set it to drop at a constant rate. For example, it may be lowered by 0.5 ° C or 0.4 ° C. This is not a fixed amount, and since there are various variables depending on the vehicle type and the capacity of the compressor 110 is also different, the most reasonable temperature is tested through a number of tests for each vehicle type. The amount of descent can be determined.

In addition, when it is determined that the air filter 152 has been replaced, the control unit 200 sets the air conditioning usage time T1 to 0 and simultaneously controls the initial target temperature and cutoff temperature to maintain the existing cooling performance.

In this case, for example, after replacing the air filter 152, the worker may notify the replacement of the air filter 152 through the control unit 230 connected to the control unit 200, and separately set the air conditioning usage time T1 to 0. can be set to In addition, the operator may check the air conditioning usage time T1 or correct the filter exchange time T2 through the display unit 240 connected to the control unit 200 .

In summary, the vehicle air conditioner according to the present invention compares the air conditioning use time (T1) and the filter exchange time (T2), and if the air conditioning use time (T1) is equal to or greater than the filter exchange time (T2), the currently set target temperature and the cutoff temperature is corrected to increase by a certain temperature, and if the air conditioning use time (T1) is lower than the filter exchange time (T2) due to the exchange of the air filter 152, the correction is recalibrated to the initial target temperature and the cutoff temperature, and this correction process It is possible to prevent the icing phenomenon of the evaporator 140 while continuously performing.

In addition, the present invention does not directly measure the amount of dust accumulated in the air filter 152, but indirectly determines through the air conditioning use time (T1), and based on this, anticipates that the amount of air entering the evaporator 140 will be reduced to target the evaporator It is characterized in that the temperature and cutoff temperature can be variably changed/corrected according to the number of stages of the blower 153.

Hereinafter, a control method of an air conditioner for a vehicle according to the present invention will be described.

3 to 5 are flowcharts illustrating a control method of an air conditioner for a vehicle according to the present invention.

First, as shown in FIG. 3, the control method of the air conditioner for a vehicle according to the present invention includes a measuring step (S100) of measuring an air conditioning use time (T1); A comparison step (S200) of comparing the air conditioning usage time (T1) and the filter exchange time (T2); A determination step of determining replacement of the air filter 152 (S300) and a change step of changing the target temperature and cutoff temperature of the evaporator 140 (S600) are included.

First, in the measuring step (S100), the control unit 200 measures the air conditioning usage time (T1). The air conditioning use time (T1) is set to 0 when the vehicle is initially shipped, and the time is accumulated after the vehicle is shipped by the control unit 200 or the blower 153 of the blowing unit 150 is driven by the motor 154 Accumulate when driven by

In the comparison step (S200), the controller 200 compares the air conditioning usage time (T1) and the filter exchange time (T2). The filter exchange time (T2) is a fixed value, for example, fixed to 2 to 3 years. It can be changed by the operator at the most reasonable time through various environments or multiple tests.

In this step, if the controller 200 determines that the air conditioning use time T1 is shorter than the filter exchange time T2, the control unit 200 controls the air conditioner with the existing evaporator 140 target temperature and cutoff temperature (S400). Conversely, when the controller 200 determines that the air conditioning use time T1 is equal to or greater than the filter exchange time T2, it determines whether the air filter 152 has been replaced (S300).

Alternatively, as shown in FIG. 4, in the comparison step (S200), the control unit 200 compares the air conditioning use time T1 and the filter exchange time T2 so that the air conditioning use time T1 is equal to the filter exchange time T2. If it is determined that the target temperature and the cutoff temperature of the evaporator 140 are variably changed according to the number of stages of the blower 153, a change step (S600) may be performed.

In the determination step (S300), it is determined whether the air filter 152 has been replaced. In this case, if it is determined that the air filter 152 has been replaced in the determination step (S300), the control unit 200 resets the air conditioning use time T1 to 0 (S500). That is, in this step, if the controller 200 determines that the air filter 152 has been replaced, the air conditioning usage time T1 is reset to 0, and the air conditioning usage time T1 is accumulated again from 0 to proceed with the calculation.

In addition, in the determination step (S300), when the control unit 200 determines that the air filter 152 has not been replaced, a change step of variably changing and controlling the target temperature and the cutoff temperature of the evaporator 140 according to the number of stages of the blower 153 (S600) is performed.

In addition, as shown in FIG. 6, the determination step (S300) may be performed separately without being bound by the comparison step (S200), and if it is determined that the air filter 152 has been replaced, the air conditioning use time (T1) is reset to 0 (S500). ) can be made.

By repeatedly performing such a process, an icing phenomenon of the evaporator 140 can be prevented.

The above-described embodiments of the vehicle air conditioner and its control method of the present invention are merely exemplary, and those skilled in the art to which the present invention belongs can make various modifications and equivalent other embodiments therefrom. You will get a good idea of the point. Therefore, it will be well understood that the present invention is not limited to the forms mentioned in the detailed description above. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims. It is also to be understood that the present invention includes all modifications, equivalents and alternatives within the spirit and scope of the present invention as defined by the appended claims.

100: engine 110: compressor
120: condenser 130: expansion valve
140: evaporator 150: blower unit
152: air filter
153: blower 154: motor
200: controller 210: evaporator outlet temperature sensor
230: control unit 240: display unit
T1: Air conditioning usage time T2: Filter replacement time
S100: Measuring step S200: Comparing step
S300: Judgment Step S600: Change Step

Claims (15)

evaporator 140; A blower 153 for blowing the air sucked through the air inlet toward the evaporator 140; In the vehicle air conditioner including an air filter 152 installed at least one of upstream and downstream of the blower 153 and a control unit 200 controlling the evaporator 140 and the blower 153,
The controller 200,
When it is determined that the air conditioning use time (T1) is equal to or greater than the filter exchange time (T2) by comparing the air conditioning use time (T1) and the filter exchange time (T2), the target temperature and the cutoff temperature of the evaporator 140 are changed and controlled to be higher. air conditioner for vehicles. delete The method of claim 1,
The air conditioning use time (T1) is the cumulative use time for the blower 153 or the accumulated time after the vehicle is shipped,
When it is determined that the air filter 152 has been replaced, the control unit 200 resets the air conditioning usage time T1 to 0 and maintains the existing cooling performance by controlling the evaporator 140 to the initial target temperature and cutoff temperature. air conditioner for vehicles. The method of claim 1,
a compressor 110 driven by the engine 100 to compress refrigerant and changing a discharge amount according to a cooling demand;
a condenser 120 condensing the refrigerant discharged from the compressor 110;
An expansion valve 130 that adiabatically expands the liquefied refrigerant passing through the condenser 120 to form a gas-liquid mixture and changes its opening according to the refrigerant discharge amount of the compressor 110,
The evaporator 140 cools the surrounding air using latent heat of vaporization when the refrigerant is vaporized, and then returns the refrigerant to the compressor 110.
A blowing unit 150 for blowing internal and external air to the evaporator 140 is provided,
An evaporator outlet temperature sensor 210 for sensing air temperature is provided at the outlet side of the evaporator 140,
The control unit 200 controls the target temperature and cutoff temperature of the evaporator 140 according to the evaporator outlet temperature input from the evaporator outlet temperature sensor 210, the air conditioning use time T1, and the filter exchange time T2. Vehicle air conditioner. The method of claim 4,
The controller 200,
If it is determined that the outlet temperature of the evaporator 140 is lower than the target temperature of the evaporator 140, the rotation speed of the compressor 110 is variably adjusted based on the changed target temperature and cutoff temperature of the evaporator 140, or the condenser ( 120) and the refrigerant pressure and amount of refrigerant discharged to the expansion valve 130 are variably adjusted, or when the temperature of the outside air is higher than the temperature of the indoor air, the outside air is introduced to prevent the temperature of the evaporator 140 from falling. Vehicle air conditioner. The method of claim 4,
The cutoff temperature of the evaporator 140 is set to a lower temperature than the target temperature of the evaporator 140,
The controller 200,
An air conditioner for a vehicle that prevents the temperature of the evaporator 140 from falling by stopping the operation of the compressor 110 when it is determined that the outlet temperature of the evaporator 140 is lower than the cutoff temperature. delete The method of claim 1,
The vehicle air conditioner further includes a display unit 240 connected to the control unit 200 so that a worker can check the air conditioning usage time T1 or correct the filter exchange time T2. A measuring step (S100) of measuring the air conditioning use time (T1) in the control unit 200;
A comparison step (S200) of comparing the measured air conditioning use time (T1) with the filter exchange time (T2) in the control unit 200; and
When the control unit 200 determines that the air conditioning use time T1 is equal to or greater than the filter exchange time T2 in the comparison step S200, the change step of changing the target temperature and the cutoff temperature of the evaporator 140 to a higher level ( S600) Control method of a vehicle air conditioner including. delete The method of claim 9,
In the comparison step (S200),
A method of controlling an air conditioner for a vehicle in which the air conditioner is controlled (S400) by changing the target temperature and cutoff temperature of the existing evaporator 140 when it is determined that the air conditioning use time (T1) is shorter than the filter exchange time (T2). The method of claim 9,
Further comprising a judgment step (S300) of determining replacement of the air filter 152,
In the judgment step (S300),
In the comparison step (S200), when it is determined by the controller 200 that the air conditioning use time (T1) is equal to or greater than the filter exchange time (T2) and it is determined that the air filter (152) needs to be replaced, the evaporator (140) ) Control method of a vehicle air conditioner performing a change step (S600) of variably changing the target temperature and the cutoff temperature. The method of claim 9,
Further comprising a judgment step (S300) of determining replacement of the air filter 152,
In the judgment step (S300),
A control method of an air conditioner for a vehicle in which the air conditioning usage time T1 is reset to 0 (S500) when it is determined by the controller 200 that the air filter 152 is to be replaced. delete The method of claim 9,
The controller 200,
Based on the target temperature and cutoff temperature of the evaporator 140 changed in the changing step (S600), the rotation speed of the compressor 110 is variably adjusted, or the refrigerant pressure and amount of refrigerant discharged to the condenser 120 and the expansion valve 130 side. A method of controlling an air conditioner for a vehicle by variably controlling or preventing the temperature of the evaporator (140) from falling by introducing outside air when the temperature of the outside air is higher than the temperature of the indoor air.

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