JP3344249B2 - 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 for achieving air conditioning in a vehicle compartment, and more particularly to an air conditioner for a vehicle capable of preventing fogging due to dew condensation on a windshield glass of the vehicle.

[0002]

2. Description of the Related Art A vehicle air conditioner (hereinafter referred to as "air conditioner") controls power (cooling capacity) in accordance with the temperature of air blown into a vehicle cabin, thereby saving power (power saving). There are things that I try to do. For example, in an air conditioner using a variable capacity compressor, the discharge capacity of the variable capacity compressor is reduced.During heating operation, the temperature of the air passing through the evaporator is increased by reducing the discharge capacity of the variable capacity compressor. By preventing the temperature from decreasing, the ability of the heating means for heating the air cooled by the evaporator to a predetermined temperature can be suppressed, and efficient air conditioning can be achieved.

[0003] Usually, when the discharge capacity of the variable displacement compressor is reduced, the refrigerant pressure in the evaporator increases, and accordingly, the amount of dehumidification from the air passing through the evaporator decreases. When the dehumidifying ability of the evaporator decreases, the dew point temperature of the air in the vehicle compartment also increases, and when the outside air temperature is low, the temperature of the windshield glass and the like also decreases. .

[0004] In order to prevent the windshield glass from fogging due to power saving by such an air conditioner, not only the room temperature and a set temperature (target temperature) but also environmental conditions such as the outside air temperature and the amount of solar radiation are considered. Then, the temperature after the evaporator is determined, and the capacity of the compressor is controlled so as to obtain the determined temperature after the evaporator (for example, Japanese Patent Publication No. 8-494).

[0005] In an air conditioner provided in a vehicle, an inside air circulation mode for circulating air in the vehicle compartment and an outside air introduction mode for introducing outside air into the vehicle compartment via an evaporator can be selected. In any case, dehumidified air is blown into the vehicle compartment by passing through an evaporator according to the capacity of the compressor.

[0006]

However, when the air conditioner of the vehicle is used in the outside air introduction mode, the air outside the vehicle is pumped into the vehicle interior by the blower fan, so that the internal pressure (air pressure) in the vehicle interior increases. On the other hand, when the air conditioner is used in the internal air circulation mode, only the air in the vehicle compartment is circulated, so that the internal pressure in the vehicle compartment does not increase.

On the other hand, there is a gap in the vehicle body, and the outside air enters the vehicle compartment from this gap without being dehumidified. In the inside air circulation mode and the outside air introduction mode, the amount of air that is not dehumidified outside the vehicle that enters the vehicle interior through the gap between the vehicle bodies increases in the internal air circulation mode in which the internal pressure in the vehicle interior does not increase. For this reason, there is a problem that the humidity in the vehicle compartment becomes higher in the inside air circulation mode as it is, and the window is easily fogged. If the temperature after the evaporator is lowered in any mode of the air intake in order to prevent this, it is against power saving.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances. In a vehicle air conditioner for controlling the cooling capacity of a compressor, the humidity in the vehicle interior increases during the internal air circulation while maintaining power saving. It is an object of the present invention to propose an air conditioner for a vehicle that prevents fogging of a shield glass.

[0009]

The invention according to claim 1 is
A vehicle air conditioner for blowing air conditioned by a refrigeration cycle including an evaporator and a compressor into a vehicle interior of a vehicle to perform air conditioning, wherein after a target evaporator based on a second characteristic set in advance when outside air is introduced. A second post-evaporator temperature setting means for setting the temperature, and in accordance with natural ventilation when the cooling load is small during circulation of the inside air.
The temperature after the target evaporator becomes lower than the second characteristic
A first post-evaporator temperature setting means for setting a target post-evaporator temperature based on a first characteristic preset in advance, a judgment means for judging whether internal air circulation or external air introduction, and the judgment means Evaporator temperature determining means for selecting one of the first post-evaporator temperature setting means and the second post-evaporator temperature setting means based on the determination result to determine the target post-evaporator temperature, and the post-evaporator temperature determination. Compressor control means for controlling the compressor based on the target post-evaporator temperature determined by the means.

According to this invention, the target evaporator temperature is set based on the target evaporator temperature based on the first characteristic set for the internal air circulation and the second characteristic set for the outside air introduction based on the result of the judgment by the judging means. Determine the temperature. That is, the target post-evaporator temperature is determined based on the first characteristic during internal air circulation, and the target post-evaporator temperature is determined based on the second characteristic during external air introduction. This and
The windshield glass is easily clouded
At the time of loading, inside air circulation and outside air introduction are more natural
After the target evaporator during internal air circulation because the ventilation volume increases
The first characteristic is set so that the temperature decreases.

That is, since the internal pressure of the vehicle interior does not increase during the circulation of the internal air as in the case of introducing the external air, the amount of natural ventilation that enters the vehicle interior without the external air being dehumidified from a gap in the vehicle body or the like increases. From this, the first characteristic and the second characteristic are:
Cooling load determined based on environmental conditions and operating conditions,
It is set so that the target post-evaporator temperature can be determined in consideration of the natural ventilation. By setting in this way have been set first characteristic or a second temperature after the target evaporator based on the characteristics, even when the inside air circulation, can allow the optimum humidity in the passenger compartment, the passenger compartment The humidity does not increase and the user does not feel uncomfortable or fog the windshield glass.

[0012]

[0013]

[0014] Also, at the time of the external air inlet increase in humidity is low due to natural ventilation, that-out <br/> in is possible to suppress the capacity of the compressor.

According to a second aspect of the present invention, there is provided speed detecting means for detecting a running speed of the vehicle, and at least the first characteristic is such that the temperature after the target evaporator is increased in accordance with an increase in the running speed of the vehicle at a low cooling load. The post-evaporator temperature determining means determines the target post-evaporator temperature based on the detection result of the speed detecting means.

According to the present invention, at least in the first characteristic, the target post-evaporator temperature is set so as to decrease as the running speed of the vehicle increases during a low cooling load.

When the running speed of the vehicle increases, the pressure distribution of the air around the vehicle body increases, and the amount of natural ventilation that does not pass through the evaporator increases not only in the inside air circulation mode but also in the outside air introduction mode. Further, when the traveling speed of the vehicle increases, the windshield glass is cooled and the glass temperature decreases.

For this reason, when the running speed of the vehicle increases, the natural ventilation increases, and the temperature of the glass decreases, the dehumidifying capacity increases. As a result, it is possible to suppress an increase in the humidity in the vehicle interior due to natural ventilation and to reduce the rising humidity in the vehicle interior. Further, when the traveling speed is low, the temperature after the target evaporator becomes high, so that efficient air conditioning can be performed without unnecessarily increasing the power of the compressor.

According to a third aspect of the present invention, there is provided an air conditioner for a vehicle, in which air conditioned by a refrigeration cycle including an evaporator and a compressor is blown into a vehicle cabin and air-conditioned. Evaporator post-evaporator temperature setting means for setting a target evaporator post-temperature in accordance with the cooling load determined based on the performed operating conditions,
Judgment means for judging whether internal air circulation or external air is introduced, and natural conversion for increasing humidity during internal air circulation from internal air circulation when internal air circulation is judged by the judgment means.
First correction means for correcting the target post-evaporator temperature set by the post-evaporator temperature setting means when the cooling load is small, according to the need;
Compressor control means for controlling the capacity of the compressor based on the target post-evaporator temperature set by the post-evaporator temperature setting means or the target post-evaporator temperature corrected by the first correction means. I do.

According to the present invention, the temperature after the evaporator set according to the cooling load is corrected by the first correction means during the circulation of the inside air.

At the time of internal air circulation, the amount of natural ventilation in which outside air enters the passenger compartment without being dehumidified from a gap in the vehicle body or the like increases, and the temperature after the target evaporator is reduced in consideration of the increase in the amount of natural ventilation. to correct.

As a result, the dehumidifying ability of the evaporator is increased, so that it is possible to suppress an increase in the humidity of the vehicle interior due to natural ventilation, to keep the interior of the vehicle at a comfortable humidity and to prevent the windshield glass from fogging due to dew condensation. Can be.

According to a fourth aspect of the present invention, there is provided a vehicle speed detecting means for detecting a running speed of a vehicle, and a target post-evaporator temperature or the first post-evaporator temperature set by the post-evaporator temperature setting means based on a detection result of the vehicle speed detecting means. Correction means for correcting the target post-evaporator temperature corrected by the correction means, wherein the compressor control means determines the capacity of the compressor based on the target post-evaporator temperature corrected by the second correction means. Is controlled.

According to the present invention, the set temperature after the target evaporator is corrected based on the running speed of the vehicle detected by the vehicle speed detecting means.

That is, if the temperature after the target evaporator is reduced in accordance with the increase in the traveling speed of the vehicle, the amount of dehumidification by the evaporator is increased in accordance with the increase in the natural ventilation and the decrease in the glass temperature. This can prevent fogging of the windshield glass and the like.

According to the third and fourth aspects, when the inside air circulation in which the natural ventilation amount increases based on the introduction of the outside air in which the natural ventilation amount is small and when the traveling speed of the vehicle increases,
The target evaporator post-evaporator temperature is corrected or determined according to the natural ventilation volume, etc., but when the natural ventilation volume decreases based on the internal air circulation with a large natural ventilation volume and the high vehicle speed, this The temperature after the target evaporator may be increased in accordance with a decrease in the natural ventilation.

[0027]

FIG. 1 shows a vehicle air conditioner (hereinafter referred to as "air conditioner 10") applied to the present embodiment. In the air conditioner 10, a refrigeration cycle is configured by a refrigerant circulation path including a compressor (hereinafter, referred to as “compressor 12”), a condenser 14, an expansion valve 16, and an evaporator 18.

The evaporator 18 evaporates the refrigerant which has been compressed and liquefied, thereby evaporating the evaporator 18.
(Hereinafter referred to as “air after evaporator”) is cooled. At this time, the evaporator 18 cools the passing air to condense moisture in the air, thereby dehumidifying the air after the evaporator.

The expansion valve 16 provided upstream of the evaporator 18 makes the evaporator 1 mist by rapidly reducing the pressure of the liquefied refrigerant.
8 to improve the vaporization efficiency of the refrigerant in the evaporator 18.

As the compressor 12 of the air conditioner 10, various types of compressors can be used. Here, a description will be given using a conventionally known variable displacement compressor. In the present embodiment, a detailed description of a conventionally known variable displacement compressor is omitted. In the compressor 12 applied to the present embodiment, the stroke of the piston is reduced by controlling the solenoid 20 by changing the current value of the current supplied to the solenoid 20 or changing the duty ratio. It is assumed that the change changes the suction pressure of the refrigerant.

The evaporator 18 of the air conditioner 10 is provided inside the air conditioning duct 22. This air conditioning duct 2
2 is open at both ends, and air inlets 24 and 26 are formed at one open end. At the other open end, a plurality of air outlets 28 opened toward the vehicle interior are provided.
(In the present embodiment, as an example, 28A, 28B, 28C
Are shown).

The air inlet 24 communicates with the outside of the vehicle so that outside air can be introduced into the air conditioning duct 22. The air inlet 26 is in communication with the vehicle interior, so that air (inside air) in the vehicle interior can be introduced into the air conditioning duct 22.
The air outlet 28 is, for example, the air outlet 2
8A is a defroster outlet for blowing air toward a windshield glass (not shown) of the vehicle, and the air outlet 28B is a side and center register outlet, and the air outlet 28C is It has a foot outlet.

In the air conditioning duct 22, the evaporator 18
A blower fan 30 is provided between the air inlets 24 and 26. In addition, a switching damper 32 is provided near the air intakes 24 and 26. The switching damper 32 opens and closes the air intakes 24 and 26 by the operation of an actuator such as a servomotor 34.

The blower fan 30 is rotated by the drive of the blower motor 36, sucks the air from the air inlet 24 or the air inlet 26 into the air conditioning duct 22, and sends out the air to the evaporator 18. At this time, outside air or inside air is introduced into the air conditioning duct 22 according to the open / close state of the air intakes 24 and 26 by the switching damper 32.

That is, in a state where the switching damper 32 closes the air intake 24, the inside air is introduced into the air-conditioning duct 22 in the inside air circulation mode, and when the switching damper 32 closes the air intake 26, the outside air flows. Air conditioning duct 2
2 is the outside air introduction mode.

An air mix damper 38 and a heater core 40 are provided downstream of the evaporator 18.
The air mix damper 38 is rotated by the drive of the servo motor 42 to adjust the amount of air after the evaporator that passes through the heater core 40 and the amount that bypasses the heater core 40. The heater core 40 includes an air mix damper 38.
Heat the air guided by.

The air after the evaporator is guided to the heater core 40 according to the opening degree of the air mix damper 38 and is heated. Further, the air is mixed with the air not heated by the heater core 40 and then directed to the air outlet 28. Sent out. In the air conditioner 10, the air mix damper 38
By controlling the amount of air heated by the core heater 40 by controlling the temperature of the core heater 40, the temperature of the air blown out from the air outlet 28 into the vehicle compartment is adjusted.

In the vicinity of the air outlet 28, mode switching dampers 44A and 44B are provided. Air conditioner 1
At 0, the temperature-controlled air can be blown into the vehicle interior from a desired position by opening and closing the air blowout ports 28A, 28B, 28C by these mode switching dampers 44A, 44B. This mode switching damper 4
The operation of 4 may be performed by driving the servomotor 46 in accordance with the set operation mode of the air conditioner 10, but the occupant can manually open and close the air outlet 28 by manual operation. It may be something.

The air conditioner 10 has an air conditioning control circuit 50 having a microcomputer. The blower motor 36 is connected to the air conditioning control circuit 50 by the controller 5.
2 and servo motors 34, 42, 46 for operating the switching damper 32, the air mix damper 38, and the mode switching damper 44, and the compressor 1 described above.
2 are connected to solenoids 20 for controlling the suction pressure. The air conditioning control circuit 50 includes:
Along with the setting of the indoor air-conditioning temperature, the operation of the blower fan 30 is performed in a manual mode or an automatic mode, the outside air introduction mode or the inside air circulation mode, and the setting of the air outlet 28 for blowing the temperature-controlled air. An operation panel 54 for setting an operation mode (air conditioning condition) is connected. The air conditioner 10 operates based on the set conditions (air condition) set by the occupant by operating the operation panel 54.

The air conditioner 10 also includes an after-evaporator temperature sensor 56 for detecting the temperature of the air after the evaporator (hereinafter referred to as "after-evaporator temperature"), and also detects the outside air temperature outside the vehicle as environmental condition detecting means. Outside air temperature sensor 58, vehicle interior temperature sensor 6 for detecting the temperature in the vehicle interior
0 and solar radiation sensor 62 are provided, and these are connected to the air conditioning control circuit 50, respectively. Further, a vehicle speed sensor 66 for detecting the traveling speed of the vehicle is connected to the air conditioning control circuit 50.

As a result, the air-conditioning control circuit 50 determines, in addition to the cabin temperature, the outside air temperature, the post-evaporator temperature and the amount of solar radiation,
The traveling speed of the vehicle can be detected by an output signal from the vehicle speed sensor 66. The solar radiation sensor 62
Detects the brightness of the outside of the vehicle using light detecting means such as a photodiode, and the air conditioning control circuit 50 determines the amount of solar radiation from the detected brightness.

The air-conditioning control circuit 50 operates and operates the blower fan 30, the switching damper 32, the air mix damper 38, and the mode switching damper 44 based on the air-conditioning conditions set on the operation panel 54 to control the air conditioning in the vehicle compartment. Plan. At this time, the air-conditioning control circuit 50 sets the target temperature and the air volume of the air to be blown into the vehicle interior from the air outlet 28 according to the set temperature, the temperature inside the vehicle, the temperature outside the vehicle, and the solar radiation state. The driving voltage of the blower motor 36 is determined so that the blower fan 30 is rotated.

In the air-conditioning control circuit 50 of the air-conditioning apparatus 10, during normal air-conditioning operation, when air-conditioning conditions including a temperature (set temperature) are set, the air-conditioning conditions, the outside air temperature, and the temperature in the vehicle interior are used based on the air-conditioning conditions. Is calculated, and a target post-evaporator temperature (hereinafter referred to as “target evaporator temperature”) is set based on the calculation result. Thereafter, the suction pressure of the compressor 12, that is, the capacity of the compressor 12 is controlled so that the set target post-evaporator temperature is obtained, and the air conditioning in the vehicle compartment is performed. In addition, the control method at the time of the normal operation of setting the target evaporator post-temperature and controlling the suction pressure of the compressor 12 based on the setting result uses a conventionally known method of controlling the cooling capacity using a variable displacement compressor. Therefore, detailed description is omitted in the present embodiment.

The air conditioning control circuit 5 of the air conditioner 10
At 0, cooling capacity control for preventing fogging of a windshield glass (not shown) of the vehicle is performed in addition to the normal control. FIG. 2 shows a schematic configuration for performing cooling capacity control in the present embodiment.

In the air-conditioning control circuit 50, when performing the air-conditioning operation, first, the environmental condition detecting means 100 detects at least the environmental conditions such as the outside air temperature or the vehicle interior temperature and the operating conditions set on the operation panel 54. Read.

Next, the cooling load determining means 102
The cooling load HL is determined from the environmental condition and the operating condition. As the cooling load, the outside air temperature, the amount of heat entering the vehicle, the target outlet temperature, or the like can be used. Further, using the target outlet air temperature setting means as the cooling load determining means, blown from the air outlet 28 into the passenger compartment to set the target supply air temperature T _AO of the air, the target outlet air temperature T _AO from the target post-evaporator temperature T _EO You may make it set.

As shown in FIG. 3A, the target post-evaporator temperature T _EO can be set based on the cooling load HL (or the outside air temperature), and as shown in FIG. 3B. Can be set based on the target outlet temperature T _AO .

As shown in FIG. 3A, the cooling load H
L is determined according to the outside air temperature. The cooling load HL increases when the outside air temperature is high, and the cooling load H increases when the outside air temperature is low.
L also decreases. The target post-evaporator temperature T _{EO with} respect to the cooling load HL is set relatively high when the cooling load HL is in a predetermined range of “medium”. However, as the outside air temperature decreases, the target post-evaporator temperature T _EO is reduced in order to prevent fogging. It is necessary to lower the temperature T _EO .

As shown in FIG. 3B, the target post-evaporator temperature T _EO increases when the target outlet temperature T _AO is low. When calculating such target outlet air temperature T _AO is cabin set temperature T _SET, the vehicle interior temperature T _r, the outside air temperature T _o, the solar radiation amount ST, is generally expressed by the following equation.

T _AO = k ₁ · T _SET -k ₂ · _Tr -k ₃ ·
T _o -k ₄ · ST + C On the other hand _{(where, k 1, k 2, k} 3, k 4, C is a constant which is set in advance), a small cooling load, glass temperature, such as the windshield glass is reduced Occasionally, the windshield glass or the like tends to be fogged. In order to prevent windshield glass from fogging due to a decrease in glass temperature,
It becomes necessary to lower the temperature T _EO after the target evaporator.

That is, when the cooling load is lower than the predetermined value, even if the cooling load is low, the target post-evaporator temperature T _EO.
The dehumidifying capacity is increased by lowering the pressure. When the target outlet temperature T _AO is higher than the predetermined value, the cooling load is small, so the target post-evaporator temperature T _EO is reduced.

As shown in FIG. 2, when the judgment of the cooling load HL is made, the judging means 104 sucks the air in the passenger compartment from the air inlet 26, controls the temperature of the air, and adjusts the temperature of the air. It is determined whether the mode is set to the inside air circulation mode that blows out from the air inlet 28 or the outside air introduction mode that sucks outside air from the air inlet 24 and blows out the air from the air outlet 28 into the vehicle interior. This may be determined from the setting operation of the operating conditions by the operation panel 54.
The determination may be made based on which of the opening degree of the second or the servo motor 34 for rotating the switching damper 32 is instructed.

Here, when it is determined that the internal air circulation mode is set, the first post-evaporator temperature setting means 106 sets the target post-evaporator temperature T _EO based on the first characteristic and the cooling load HL. I do.

On the other hand, when it is determined that the mode is the outside air introduction mode, the second post-evaporator temperature setting means 108
Then, the target post-evaporator temperature T _EO is set based on the second characteristic and the cooling load HL.

That is, in the inside air circulation mode, only the air in the vehicle compartment is circulated by the blower fan 30, so that the pressure in the vehicle compartment does not increase as in the outside air introduction mode.

Therefore, so-called natural ventilation increases, in which outside air that has not passed through the evaporator 18 enters through a gap in the vehicle body. The outside air that enters by natural ventilation through a gap or the like in the vehicle body has a higher humidity than the air that has passed through the evaporator 18, so that the humidity in the vehicle interior increases, and the windshield glass becomes clouded due to dew condensation.

Therefore, as shown in FIGS. 3A and 3B, in the inside air circulation mode, when the cooling load HL or the target outlet temperature T _AO is the same, after the target evaporator, compared to the outside air circulation mode. The temperature T _EO is set so as to be set low. As a result, the amount of dehumidification by the evaporator 18 is increased, so that the humidity in the vehicle interior does not increase due to the air entering the vehicle interior due to natural ventilation, and the windshield glass is fogged by the natural ventilation. Try to prevent.

Further, the first post-evaporator temperature setting means 106 and the second post-evaporator temperature setting means 108 are based on the running speed of the vehicle detected by the vehicle speed sensor 66 which detects the running speed of the vehicle as necessary. The target post-evaporator temperature _TEO is also set.

The natural ventilation differs between the inside air circulation mode and the outside air introduction mode. The natural ventilation amount is naturally larger in the inside air circulation mode than in the outside air introduction mode, but also greatly varies depending on the running speed of the vehicle.

As the running speed of the vehicle increases, the pressure distribution of air around the vehicle body increases, and accordingly, the pressure difference between the vehicle interior and the outside of the vehicle body also increases. Ventilation also increases. In particular, in the inside air circulation mode, the natural ventilation increases as the traveling speed of the vehicle becomes higher than in the outside air introduction mode. In addition, when the traveling speed increases, the temperature of the glass such as the windshield glass decreases, and fogging easily occurs.

Therefore, as shown in FIGS. 4A and 4B, not only in the inside air circulation mode (see FIG. 4B) but also in the outside air introduction mode (see FIG. 4A). At the target evaporator temperature T according to the traveling speed of the vehicle.
_EO setting is required. At this time, the target post-evaporator temperature T _EO is set so as to decrease as the traveling speed of the vehicle increases.

As a result, as the running speed of the vehicle increases, the amount of dehumidification increases. As the running speed of the vehicle increases, the humidity inside the vehicle interior increases due to the outside air entering through the gaps in the vehicle body. This prevents the windshield glass from fogging due to a decrease in the glass temperature.

Based on the target post-evaporator temperature T _EO set in this way, the compressor control means 110 controls the solenoid 20 to control the compressor 1
The second capacity (discharge capacity) is controlled to perform an air-conditioning operation. Thus, in the air conditioner 10, air conditioning is performed so that the vehicle interior is at the set temperature, and fogging of the windshield glass and the like is prevented.

As shown in FIGS. 4A and 4B, at the same traveling speed, the target post-evaporator temperature T _EO is set lower in the inside air circulation mode than in the outside air introduction mode. In addition, the natural ventilation rate has a greater effect on the traveling speed of the vehicle in the inside air introduction mode than in the outside air introduction mode. After temperature T _EO
Is set to be large.

Next, the operation of the present embodiment will be described with reference to the flowchart shown in FIG. This flowchart shows an example of the cooling capacity control of the refrigeration cycle including the compressor 12 and the evaporator 18 without fogging the windshield glass while saving power.

The air-conditioning control circuit 50 has the configuration shown in FIG.
The target post-evaporator temperature T _EO with respect to the cooling load HL in the inside air circulation mode is stored as a first characteristic,
The target post-evaporator temperature T _EO with respect to the cooling load HL in the outside air introduction mode in FIG. 4B is stored as the second characteristic, and whether the air conditioner 10 is in the inside air circulation mode or the outside air introduction mode, and the vehicle speed v From target evaporator temperature T
_EO is set. These first and second characteristics are determined in advance by experimental results or calculations and stored in advance.

This flowchart is executed when the operation of the air conditioner 10 is set by a switch operation on the operation panel 54, and is repeated at a predetermined timing (a predetermined time interval).

In the first step 120, the environmental conditions and the set operating conditions are read. As the environmental conditions, the outside air temperature, the indoor temperature, and the sunshine state are measured by the outside air temperature sensor 58, the indoor temperature sensor 60, the sunshine sensor 62, and the like. As the operating conditions, a set temperature, an internal air circulation mode, an external air introduction mode, and the like are set.

After that, in step 122, the cooling load HL (outside air temperature or target outlet temperature T _AO ) and the like are set from the environmental conditions and the set operating conditions. Step 1
At 24, it is determined whether the cooling load is small based on the set cooling load HL. This is to determine whether the cooling load HL is in an area where the windshield glass is fogged.

Here, when the cooling load HL exceeds a predetermined value HL ₀ (see FIGS. 4A and 4B), dew condensation does not occur on the windshield glass or the like. Since the dehumidifying ability is obtained, step 12
The determination at step 4 is negative, and the routine goes to step 126. In step 126, the target post-evaporator temperature T _EO is determined based on the first characteristic or the second characteristic and the cooling load HL.

On the other hand, the cooling load HL is small and the predetermined value HL ₀
When the temperature is below the threshold, it can be determined that there is a possibility that the windshield glass or the like may be fogged due to a decrease in the temperature of the windshield glass or the like.
In step 128, it is determined whether the internal air circulation mode or the external air introduction mode has been set.

When the outside air introduction mode is set, a negative determination is made in step 128 and the routine proceeds to step 130. In this step 132, the traveling speed v of the vehicle detected by the vehicle speed sensor 66 is read, and in the next step 132, the second characteristic stored for setting the target post-evaporator temperature T _EO in the outside air introduction mode. The target post-evaporator temperature T _EO is set based on (FIG. 4B), the cooling load HL, and the traveling speed v of the vehicle.

When the air conditioner 10 is set to the inside air circulation mode, the determination at step 128 is affirmative, and the routine proceeds to step 134. In step 134, the running speed v of the vehicle detected by the vehicle speed sensor 66 is read in the same manner as in step 130 described above.

Thereafter, in step 136, the inside air introduction mode
Temperature after target evaporator T _EOTo set
The stored first characteristic, the cooling load HL, and the running of the vehicle
The target post-evaporator temperature T based on the line speed v_EOThe set
I do.

The reason why the target post-evaporator temperature T _EO is different between the outside air introduction mode and the inside air circulation mode is that there is a difference in the natural ventilation between the outside air introduction mode and the inside air circulation mode.

In the air conditioner 10, when the target post-evaporator temperature T _EO is determined based on the environmental conditions, set operating conditions (set temperature, internal air circulation mode or external air introduction mode, etc.) and the running speed v of the vehicle, the evaporator 10 The capacity of the compressor 12 is controlled so that the temperature of the rear air becomes equal to the target post-evaporator temperature T _EO , thereby achieving air conditioning in the vehicle interior.

This prevents the humidity in the passenger compartment from rising due to the air entering through the gaps in the vehicle body due to natural ventilation, and prevents the humidity in the vehicle interior from increasing due to the air entering through the natural ventilation and fogging the windshield glass and the like. Can also be reliably prevented.

On the other hand, if the target post-evaporator temperature T _EO is set low irrespective of the cooling load HL or the like, it is possible to prevent the humidity in the vehicle compartment from rising and the windshield glass from fogging. However, setting the target post-evaporator temperature T _{EO too} low unnecessarily increases the capacity of the compressor 12 and hinders efficient operation of the air conditioner 10.

On the other hand, in the air conditioner 10 applied to the present embodiment, the target post-evaporator temperature T _EO is determined according to the operation mode of the inside air circulation mode or the outside air introduction mode and the traveling speed of the vehicle. , The capacity of the compressor 12 is controlled _. Therefore, for example, when the traveling speed v and the cooling load HL are the same, the target post-evaporator temperature T _EO is higher in the outside air introduction mode than in the inside air circulation mode.
Does not unnecessarily lower the target evaporator post-evaporator temperature T _EO . That is, since the target post-evaporator temperature T _EO can be set appropriately _{, the} compressor 12 is set to an appropriate capacity and operated efficiently.

FIGS. 4A and 4B show an outline for setting the target post-evaporator temperature T _EO with the traveling speed v as a parameter with respect to the cooling load HL. The value of the traveling speed v is not limited to the description in the figure.

In this embodiment, the target post-evaporator temperature T _EO is set based on the first or second characteristic depending on whether the air circulation mode or the outside air introduction mode is used. However, the target temperature set based on the cooling load HL is set. Temperature T _EO after evaporator
May be corrected according to whether the inside air circulation mode is the outside air introduction mode. That is, as shown in FIG. 6, when the setting of the cooling load HL and the determination of the set cooling load HL are performed by the cooling load determining means 102, the cooling load HL is then set to the set cooling load HL by the post-evaporator temperature setting means 112. Based on this, the target post-evaporator temperature T _EO is set.

Thereafter, when the determination means 104 determines that the internal air circulation mode is set, the first correction means 114 determines the cooling load HL by the cooling load determination means 102.
Is determined to be low, the target evaporator post-evaporator temperature T _EO is corrected so that the dehumidifying capacity is increased. Also,
The second correction means 116 further corrects the target post-evaporator temperature T _EO based on the detection result of the vehicle speed sensor 66.

As a result, FIG. 4A or FIG.
Optimal target post-evaporator temperature T as well as based on
_EO can be determined.

In this case, the target post-evaporator temperature T _EO is set in accordance with the increase in the natural ventilation when the inside air circulation mode is set based on the outside air circulation mode. However, the invention is not limited to this. The target post-evaporator temperature T _EO may be set to be higher in accordance with a decrease in the natural ventilation when the outside air introduction mode is set, based on the circulation mode.

Further, a predetermined running speed (for example, 10
(0 km / h) as a reference, the target post-evaporator temperature T _EO may be set to be higher in accordance with the natural ventilation that decreases as the traveling speed v decreases.

The configuration of the present embodiment described above does not limit the configuration of the vehicle air conditioner to which the present invention is applied. Although the present embodiment has been described using a variable capacity compressor, the cooling capacity may be controlled by turning on / off the compressor at a temperature after the target evaporator, or in a method of rotating the compressor by a motor, By adjusting the number, the cooling capacity may be controlled such that the target post-evaporator temperature is maintained at the set temperature. The present invention is applicable to various vehicle air conditioners that vary the cooling capacity using a compressor. .

[0087]

As described above, according to the present invention, the target post-evaporator temperature is corrected in accordance with the natural ventilation rate which increases from the time of introduction of outside air during the circulation of inside air. In addition, the temperature after the target evaporator is changed in accordance with the natural ventilation amount that changes depending on the running speed of the vehicle and the decrease in the temperature of the glass such as the windshield glass. For this reason, the compressor is not operated with an unnecessarily high capacity, and efficient air-conditioning of the vehicle interior is enabled. In addition, in the present invention, since the target evaporator temperature is set in accordance with the natural ventilation, even when the natural ventilation is increased, the interior of the vehicle can be kept at a comfortable humidity, and the windshield glass and the like can be formed by condensation. An excellent effect that no fogging occurs is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner applied as an example of a vehicle air conditioner.

FIG. 2 is a functional block diagram for setting a target post-evaporator temperature for controlling a compressor according to the present embodiment.

3A is a characteristic diagram illustrating a change in a target post-evaporator temperature with respect to a cooling load, and FIG. 3B is a characteristic diagram illustrating a change in a target post-evaporator temperature with respect to a target outlet temperature.

FIG. 4A is a characteristic diagram schematically showing a first characteristic, showing a change in a temperature after a target evaporator with respect to a cooling load using a traveling speed in an inside air circulation mode as a parameter, and FIG.
FIG. 9 is a characteristic diagram showing a change in the temperature after the target evaporator with respect to the cooling load, using the traveling speed in the outside air introduction mode as a parameter, schematically showing the second characteristic.

FIG. 5 is a flowchart showing an example of setting a target post-evaporator temperature for controlling the cooling capacity of the compressor according to the present embodiment.

FIG. 6 is a functional block diagram for setting a target post-evaporator temperature for controlling a compressor applicable to the present invention.

[Explanation of symbols]

Reference Signs List 10 air conditioner (vehicle air conditioner) 12 compressor 18 evaporator 24 air intake (introduction of outside air) 36 air intake (inside air circulation) 32 switching damper 50 air conditioning control circuit 54 operation panel 58 outside temperature sensor 60 vehicle temperature sensor 62 sunlight Sensor 66 Vehicle speed sensor (running speed detection means) 104 Judgment means (judgment means, temperature determination means after evaporator) 106 First temperature setting means after evaporator 108 Second temperature setting means after evaporator 110 Compressor control means 112 Temperature setting after evaporator Means 114 First correction means 116 Second correction means

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60H 3/00 B60H 1/00 101 B60H 1/32 624

Claims (4)

(57) [Claims] 1. A vehicle air conditioner for blowing air conditioned by a refrigeration cycle including an evaporator and a compressor into a vehicle interior of a vehicle to air-condition the vehicle, wherein the air conditioner has a second characteristic preset at the time of introducing outside air. a second post-evaporator temperature setting means for setting a target post-evaporator temperature based, during recirculated air, natural increase the humidity than when outside air introducing
The second characteristic when the cooling load is small in accordance with the ventilation
First post-evaporator temperature setting means for setting the target post-evaporator temperature based on the first characteristic preset so that the target post-evaporator temperature becomes lower, and determining whether internal air circulation or external air introduction is to be performed. Determining means for determining the target temperature after the evaporator by selecting either the first temperature setting means after the evaporator or the second temperature setting means after the evaporator based on the determination result of the determining means. Means, and compressor control means for controlling the compressor based on the target post-evaporator temperature determined by the post-evaporator temperature determining means. 2. A vehicle comprising a speed detecting means for detecting a running speed of the vehicle, wherein at least the first characteristic is determined so that the temperature after the target evaporator becomes lower in accordance with an increase in the running speed of the vehicle at a low cooling load. , air-conditioning system according to claim 1, wherein the post-evaporator temperature determining means determines the target post-evaporator temperature based on a detection result of the speed detecting means. 3. An air conditioner for a vehicle for air-conditioning by blowing air conditioned by a refrigeration cycle including an evaporator and a compressor into a vehicle interior of a vehicle, based on environmental conditions of the vehicle and set operating conditions. Evaporator temperature setting means for setting a target post-evaporator temperature in accordance with the cooling load determined in the above-described manner; determining means for determining whether internal air circulation or external air introduction is provided; and determining means determines that internal air circulation is present. inside at the time was
For natural ventilation that increases humidity during air circulation compared to when introducing outside air
In addition, first correction means for correcting the target post-evaporator temperature set by the post-evaporator temperature setting means to decrease when the cooling load is small, and after the target evaporator set by the post-evaporator temperature setting means. An air conditioner for a vehicle, comprising: compressor control means for controlling the capacity of the compressor based on a temperature or a target post-evaporator temperature corrected by the first correction means. 4. A vehicle speed detecting means for detecting a running speed of the vehicle, and a target post-evaporator temperature set by the post-evaporator temperature setting means or a target post-evaporator temperature corrected by the first correcting means. Second correcting means for correcting based on the detection result of the means,
Wherein the compressor control means controls the capacity of the compressor based on the target post-evaporator temperature corrected by the second correction means.
The vehicle air conditioner according to claim 3 .