JPH07108821A - Air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To make defogging control surely while saving fuel consumption when blowing air into a cabin is cooled temporarily to a specified temperature when the condition under which window glass is fogged is encountered. CONSTITUTION:A control device obtains the temperatures TE1, TE2, and TE3 at the outlet of an evaporator which are required to carry out the temperature adjustment control, comfortable humidity control, and defogging control in Step T1 based on the environment conditions, and sets the outlet temperature of the evaporator at the minimum in Step T2. In this case, when the control device judges that the outlet temperature TE3 of the evaporator required to carry out the defogging control is Step T6 is minimum, it holds the outlet temperature of the evaporator at a specified temperature lower than the temperature TE3 for a specified time in Steps T13 and T14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner for dehumidifying blown air when the window glass of a vehicle becomes cloudy.

[0002]

2. Description of the Related Art Conventionally, as an air conditioner for a vehicle, by detecting or estimating the humidity in the passenger compartment, when the window glass becomes cloudy, the outlet temperature of the evaporator is cooled to an anti-fog set temperature. The one of the composition is provided. In other words, the fact that the window glass becomes cloudy depends on the environmental conditions of the outside air temperature and the vehicle interior humidity, so when the window glass becomes cloudy based on these relationships, the evaporator is adjusted to the extent that the window glass does not become cloudy. The blown air is dehumidified and cooled. In this case, since it is necessary to maintain the temperature inside the vehicle interior at the set temperature, the air blown into the vehicle interior is once cooled to the anti-fog set temperature and then raised to the target air outlet temperature by the heater core.

[0003]

However, in the above-mentioned conventional example, when the anti-fog set temperature for the anti-fog operation is set to be low, the dehumidification amount of the air blown into the vehicle interior increases and Although the clouding effect is enhanced, the fuel saving effect is reduced. On the other hand, when the antifogging set temperature is set to be high, the fuel saving effect is high, but the antifogging function is deteriorated and there is a problem from the viewpoint of safety.

The present invention has been made in view of the above circumstances. An object of the present invention is to save the air blown into the passenger compartment to a predetermined temperature once when the windshield of the vehicle becomes cloudy. An object of the present invention is to provide a vehicle air conditioner capable of reliably preventing fogging while improving fuel efficiency.

[0005]

A vehicle air conditioner of the present invention is provided with a duct for introducing air into a vehicle compartment, and dehumidifying means for cooling / dehumidifying air passing through the duct in response to driving of a compressor. And a blowout temperature adjusting means for adjusting the temperature of the air that passes through the dehumidifying means and is blown into the vehicle interior. The target blowout temperature is obtained according to various conditions and the blowout temperature into the vehicle interior becomes the target blowout temperature. Thus, the compressor is provided such that the first control means for controlling the blow-out temperature adjusting means is provided and the cooling temperature by the dehumidifying means becomes a predetermined anti-fog setting temperature when a fog condition for fogging the window glass of the vehicle is satisfied. A second control means is provided for executing the anti-fog standby operation for driving the motor, and when the second control means executes the anti-fog standby operation, the cooling temperature by the dehumidifying means is lower than the anti-fog set temperature. The constant temperature is provided with a subcooling means for holding a predetermined time.

[0006]

The first control means obtains the target blowout temperature according to various conditions, and drives the blowout temperature adjusting means so as to reach the target blowout temperature. At this time, the second control means drives the compressor so that the cooling temperature by the dehumidifying means becomes a predetermined anti-fog setting temperature capable of removing the fogging of the window glass when the fogging condition for fogging the window glass of the vehicle is satisfied. Then, the anti-fog standby operation is executed.

Now, when the second control means executes the anti-fog standby operation, the sub-cooling means controls the compressor so that the cooling temperature by the dehumidifying means is maintained at a predetermined temperature lower than the anti-fog set temperature for a predetermined time. To drive. Therefore, even when the anti-fogging set temperature is set high to save fuel consumption, the fogging of the window glass can be reliably removed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an automobile air conditioner will be described below with reference to the drawings.
FIG. 1 shows an overall functional block configuration. In an air duct 1 arranged in the front part of a vehicle compartment (not shown), an inside / outside air switching damper 2 is rotatably provided at an upstream side inlet thereof, and a downstream side thereof is provided. Is equipped with a blower 3. The inside / outside air switching damper 2 is driven by a servomotor 2a, and has an air intake port at the inside air introduction port 4a or the outside air introduction port 4b.
Switch to either. The blower 3 is rotationally driven by a blower motor 5, sucks air from the side where either the inside air inlet 4a or the outside air inlet 4b is set and blows the air to the downstream side.

The evaporator 6 as a dehumidifying means is a blower 3
Is arranged on the downstream side, cools the air sent by the blower 3, and sends it to the downstream side, which is one of the elements constituting the refrigeration cycle 7. The refrigeration cycle 7 includes the evaporator 6, the evaporator 8, the condenser 9, the receiver 10, and the expansion valve 11, and the evaporator 6.
It is formed such that the refrigerant circulates in the interior of the compressor, and the cooling function of the evaporator 6 can be obtained by operating the compressor 8.

The air mix damper 12, which is a blowout temperature adjusting means, is rotatably provided on the downstream side of the evaporator 6 and is driven by a servomotor 12a. A heater core 13 that constitutes a dehumidifying means together with the evaporator 6 is disposed downstream of the air mix damper 12 so as to occupy a part of the air duct 1. The heater core 13 heats air by using engine cooling water (not shown) as a heat source, and heats cold air sent from the evaporator 6.
The air mix damper 12 distributes the cool air sent from the evaporator 6 to the heater core 13 and the bypass passage 14 according to the opening degree set by the servo motor 12a.

Three outlets, a defrost outlet 15, a face outlet 16 and a foot outlet 17, are provided on the outlet side of the air duct 1, and a defrost outlet damper 18 and a face outlet are provided corresponding to the three outlets. Exit damper 19
Also, a foot outlet damper 20 is provided. The outlet dampers 18 to 20 are servomotors 18a to 20a, respectively.
Driven by.

The defrost outlet port 15 is arranged toward the surface of the window glass 21 on the inside of the vehicle compartment, and the servo motor 1 is provided.
By opening the defrost outlet damper 18 by 8a, it becomes possible to blow air to the window glass 21.

The control device 22 as the first control means, the second control means and the supercooling means comprises a CPU 22a and a ROM.
22b and RAM 22c and the like,
An automatic air conditioning control program for air conditioning control is stored in advance. The ROM 22b stores a target outlet temperature at which the compressor 8 can be stopped according to the outside air temperature and the outside air humidity, which will be described later.

The output terminals A to E of the control device 22 are connected to the servomotors 2a, 12a, 18a and 20 respectively.
a and 19a, and the output terminal F is connected to the blower motor 5 via the drive circuit 5a. Servo motor 1
An air mix damper opening sensor 12b for detecting the opening θ of the air mix damper 12 is provided at 2a and is connected to an input terminal G of the control device 22.

The output terminal H of the control device 22 is connected to an electromagnetic clutch (not shown) of the compressor 8 via a drive circuit 8a, and the coil of the electromagnetic clutch is energized to rotate the engine. Is transmitted to drive the compressor 8. The drive circuit 8a has a function of detecting a current flowing through the coil of the electromagnetic clutch, and its output terminal is connected to the input terminal I of the control device 22.

The input terminals J to L of the control device 22 are connected to an inside / outside air changeover switch 23, a temperature setting switch 24 and a defrost mode setting switch 25 arranged on an operation panel (not shown), and the input terminals M to R are connected to each other. Inside air sensor 26, outside air sensor 27, water temperature sensor 2 respectively
8, the solar radiation sensor 29, the evaporator sensor 30, and the inside air humidity sensor 31 are connected.

The inside air sensor 26 and the outside air sensor 27
Respectively detect the temperatures Tr and Tam inside and outside the vehicle, the water temperature sensor 28 detects the cooling water temperature Tw of the engine, the solar radiation sensor 29 detects the solar radiation amount Ts incident on the vehicle interior, and the indoor air humidity sensor 31. Detects the relative humidity RHr in the vehicle compartment.

Next, the operation of this embodiment will be described with reference to FIGS. When the power supply is turned on and the air conditioning control program is started, the control device 22 executes control according to the flowchart of FIG. That is, the control device 2
2. First, in step S1, initialization processing is performed in step S1 to initialize various counters and flags, and then step S2.
Move to.

The control unit 22 determines in step S2 that
Read the set temperature Tset from the temperature setting switch 24, and
It is stored in the AM 22c. Subsequently, in step S3, the control device 22 reads detection signals from various sensors to detect the vehicle environmental condition. That is, the control device 22
The inside air temperature (room temperature) Tr from the inside air sensor 26, the outside air temperature Tam from the outside air sensor 27, the engine cooling water temperature Tw from the water temperature sensor 28, the amount of solar radiation Ts from the solar radiation sensor 29, and the outlet temperature Te of the evaporator 6 from the evaporator sensor 30.
The relative humidity RHr in the vehicle compartment is read from the inside air humidity sensor 31 and stored in the RAM 22c.

Next, in step S4, the control device 22 determines the ROM 22b based on the read various data.
The target blow-out temperature Tao is calculated by the arithmetic expression stored in advance in
To calculate. In this case, the data set temperature Tset
, The inside air temperature Tr, the outside air temperature Tam and the amount of solar radiation Ts are substituted into the arithmetic expression shown in the following equation (1) to obtain the target outlet temperature Tao.

Tao = A × Tset + B × Tr + C × Tam + D × Ts + E (1) where A to E are arbitrary constants for setting the gain.

Subsequently, in step S5, the controller 22 sets the blower voltage Ve based on the set temperature Tset read and stored in steps S2 and S3 and the detection signals from various sensors for detecting the environmental condition. The blower voltage Ve is a voltage applied to the blower motor 5 via the drive circuit 5a in order to set the amount of air blown by the blower 3.

When the control device 22 goes to step S6,
ROM2 based on various data stored in RAM22c
The target opening θo of the air mix damper 12 is calculated by an arithmetic expression previously stored in 2b. In this case, as the data, the target outlet temperature Tao, the cooling water temperature Tw, and the outlet temperature Te of the evaporator 6 are used, and the target opening degree of the air mix damper 12 is calculated by substituting them into the arithmetic expression shown in the following equation (2). Find θo.

Θo = [(Tao−Te) / (Tw −Te)] × 100 (%) (2) Next, in step S 7, drive / stop processing of the compressor 8 is performed. Then, based on the results obtained in the above steps, a control signal is output in step S8 to control the air conditioning in the vehicle compartment.

In this case, the control device 22 gives a blower drive signal to the drive circuit 5a to drive the blower motor 5 at the blower voltage Ve, thereby operating the blower 3 at a predetermined air flow rate. Further, the control device 22 gives an air mix damper opening control signal to the servomotor 12a, and controls the opening θ of the air mix damper 12 to be the target opening θo calculated in step S6. Further, the control device 22
Outputs an inside / outside air introduction mode control signal to the servomotor 2a to drive the inside / outside air switching damper 2 to a predetermined position.

Subsequently, the control device 22 then proceeds to step S
Wait until a predetermined control period τ has passed after shifting to 9,
After this, the above steps are repeated again. Therefore, the control device 22 repeatedly executes the above-described program at regular intervals, thereby performing the air conditioning control according to the set temperature Tset and the vehicle environment state to maintain the vehicle interior in a comfortable state.

Now, in the state where the air conditioning control is performed in this way, the compressor 8 which is operated in step S7
The drive / stop processing of will be described. FIG. 3 shows the drive / stop processing of the compressor 8. In FIG. 3, the control device 22 sets the outlet set temperature of the evaporator 6 (hereinafter, referred to as “temperature adjustment control”, “comfort humidity control”, and “anti-fog control”) in step T1.
Calculated as the post-evaporator set temperature).

Here, the temperature control is control for driving the compressor 8 so as to reach the post-evaporator set temperature TE1 according to the target outlet temperature TAO as shown in FIG. Further, the comfortable humidity control is to drive and stop the compressor 8 so as to reach the post-evaporator set temperature TE2 according to the vehicle interior humidity as shown in FIG. 5, and when the vehicle interior humidity exceeds the upper limit set value. Drives the compressor 8 to perform dehumidifying operation,
When the vehicle interior humidity is below the lower limit set value, the compressor 8
Is a control to stop. The anti-fog control is a control for driving the compressor 8 so as to reach the post-evaporation set temperature TE3 when the vehicle interior humidity reaches the fog limit indoor humidity with respect to the outside temperature as shown in FIG.

Now, the control unit 22 controls the post-evaporator set temperature obtained as described above, that is, TE1 for temperature adjustment,
The control content for the compressor 8 thereafter is determined according to the smallest value of TE2 for maintaining comfortable humidity and TE3 for anti-fogging. That is, in order to properly execute all the control of temperature adjustment, comfortable humidity maintenance, and antifogging, the compressor 8 is driven so that the post-evaporator set temperature becomes the minimum value of TE1 to TE3 obtained in step T1. It is necessary.

Therefore, the controller 22 first compares the minimum value of TE1, TE2 and TE3 with the current post-evaporator set temperature TE in step T1. At this time, when the current post-evaporator set temperature TE is larger than the minimum value, it is necessary to change the setting of the post-evaporator set temperature TE. Therefore, after setting t = 0 in step T3, steps T4 to T4 are performed. At T6, the minimum value is selected from TE1, TE2 and TE3. At this time, when TE1 for temperature control is the minimum value, it is determined in step S7 whether the target outlet temperature TAO is higher than the predetermined temperature α above the outside air temperature TAM which is the intake temperature of the air duct 1. , TAO> TAM + α, the compressor 8 is driven / stopped in step T8.

That is, when the outside air passes through the air duct 1, the ambient temperature raises the temperature by a predetermined temperature α (for example, 5 ° C.), so that the target outlet temperature TAO is higher than the outside air temperature by a predetermined temperature. When TAO> TAM + α, the compressor 8 can be stopped. If TAO> TAM + α is not satisfied in step T7, TE1 is set to TE in step T9.

On the other hand, when TE2 for maintaining comfortable humidity is minimum, TE2 is set to TE2 in step T10, and when TE3 for anti-fogging is minimum, step T1 is set.
In 1, TE is set to TEmin (for example, 3 ° C.).
Then, after setting the post-evaporator set temperature TE, the control device 22 executes the drive process of the compressor 8 in step T12.

After setting the post-evaporator set temperature TE as described above, the control device 22 returns to the main routine to control the compressor 8 so that the set post-evaporator temperature TE is reached. When the control period τ elapses,
The drive / stop processing of the compressor 8 is executed again. At this time, in the previous drive / stop processing of the compressor 8, when TEmin is set as the post-evaporator set temperature TE, the control device 22 determines “YES” in step T2.
Then, the anti-fog standby operation is executed.

In this anti-fog standby operation, first, step T
At 13, it is determined whether t> tmax (for example, 300 sec). At this time, since t = 0, the control cycle τ in the main routine is counted up by setting t = t + τ in step T14, and then the drive / stop processing of the compressor 8 is executed in step T15. When t> tmax due to the repeated execution of the drive / stop processing of the compressor 8, t = 0 is set in step T16 and TE is set to the minimum value of TE1, TE2 and TE3 in step T17. After that, the drive / stop processing of the compressor 8 is executed.

According to the above structure, when the window glass 21 becomes cloudy on the basis of the outside air temperature and the vehicle interior humidity, the post-evaporation set temperature TE is set to prevent the window glass 21 from becoming cloudy. The anti-fog standby operation of driving the compressor 8 to reach the temperature is executed, and at the start of the anti-fog standby operation, the post-evaporation set temperature TE is held at a predetermined temperature TEmin lower than the anti-fog set temperature for a predetermined time tmax. Therefore, unlike the conventional example in which the post-evaporator set temperature must be set to a relatively low temperature in order to exhibit a sufficient anti-fog effect, the compressor can be set to a higher anti-fog set temperature by setting it higher. It is possible to reliably remove the fog on the window glass 21 while reducing the driving rate of No. 8 to perform fuel-saving driving.

In the above embodiment, the inside air humidity sensor 31 is used.
Although the humidity inside the vehicle is detected by the above, instead of this, the humidity inside the vehicle may be estimated based on environmental conditions such as the outside temperature and the outside humidity.

[0037]

As is apparent from the above description, according to the vehicle air conditioner of the present invention, the compressor is arranged so that the cooling temperature by the dehumidifying means becomes the predetermined anti-fog set temperature at which the window glass of the vehicle is not fogged. When the anti-fog standby operation to be driven is executed, the cooling temperature by the dehumidifying means is kept at a predetermined temperature lower than the anti-fog set temperature for a predetermined time, so that the window condition of the vehicle becomes cloudy. In this case, in the configuration in which the air blown into the vehicle interior is once cooled to a predetermined temperature, it is possible to achieve an excellent effect that it is possible to reliably prevent fogging while achieving fuel efficiency.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine operation of the control device.

FIG. 3 is a flowchart showing a subroutine operation of the control device.

FIG. 4 is a control characteristic diagram showing a relationship between a target outlet temperature and a post-evaporator set temperature in temperature control.

FIG. 5 is a control characteristic diagram showing a relationship between a vehicle interior humidity and a post-evaporator set temperature in comfortable humidity control.

FIG. 6 is a characteristic diagram showing the relationship between the outdoor temperature and the fog-limit indoor humidity in anti-fogging control.

[Explanation of symbols]

1 is an air duct, 6 is an evaporator (dehumidifying means), 8 is a compressor, 12 is an air mix damper (blowout temperature adjusting means), 13 is a heater core (dehumidifying means), 22 is a controller (first controller, second controller). Control means, supercooling means) 31 is an inside air humidity sensor.

Claims (1)

[Claims] 1. A duct for introducing air into a passenger compartment, a dehumidifying means for cooling and dehumidifying air passing through the duct in response to driving of a compressor, and a dehumidifying means for blowing air into the passenger compartment. A blowout temperature adjusting means for adjusting the air temperature, and a first control means for obtaining a target blowout temperature according to various conditions and controlling the blowout temperature adjusting means so that the blowout temperature into the passenger compartment becomes the target blowout temperature. And second control means for executing an anti-fog standby operation for driving the compressor so that the cooling temperature by the dehumidifying means becomes a predetermined anti-fog setting temperature when a fog condition for fogging the window glass of the vehicle is satisfied. The second control means includes a supercooling means for holding the cooling temperature by the dehumidifying means at a predetermined temperature lower than the antifogging set temperature for a predetermined time when the antifogging standby operation is performed. Vehicle air conditioner according to claim.