JP2817260B2 - Vehicle air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle air conditioner that automatically controls a temperature in a vehicle cabin to a set temperature.

[Prior Art] As a conventional technique, a technique disclosed in JP-A-58-33516 is known. This technique determines and controls the cooling capacity of the cooling means from vehicle conditions such as the outside temperature of the vehicle, the amount of solar radiation, the temperature of the vehicle interior, and the set temperature.

With this technique, the power consumption of the cooling means can be kept low. Specifically, if the cooling means is a refrigerant evaporator of a refrigeration cycle, the operating rate of the refrigerant compressor is reduced,
This is to reduce the power applied to the refrigerant compressor.

[Problems to be Solved by the Invention] However, in the above-described conventional technology, when, for example, the room temperature is lower than a set temperature, that is, when performing a heating operation, the cooling means does not operate, or even if it operates, the cooling means does not perform cooling. Ability is small. Therefore, when the room temperature is lower than the set temperature, the indoor unit cannot be dehumidified by the cooling means.

For this reason, even when the air conditioner is operated during high humidity, such as rainy weather and the rainy season, immediately after the operation of the air conditioner is disclosed,
If the surface temperature inside the window glass is lower than the set temperature,
There was a problem that fogging occurred in the window glass.

An object of the present invention is to provide an air conditioner for a vehicle that suppresses power consumption of a cooling unit and prevents fogging of a window glass.

[Means for Solving the Problems] To achieve the above object, the vehicle air conditioner of the present invention employs the following technical means (see FIG. 5).

The air conditioner for a vehicle includes a duct for sending air toward the passenger compartment, a blower that generates an airflow toward the passenger compartment in the duct, and air that is disposed in the duct and that is blown into the passenger compartment. Cooling means for cooling; heating means arranged in the duct downstream of the cooling means for heating air blown into the vehicle interior; cooling capacity of the air by the cooling means; and heating capacity of the air by the heating means And a control circuit for controlling the temperature of the room to be equal to the set temperature.

The control circuit includes a cooling capacity determining unit that detects a vehicle state such as a vehicle exterior temperature and a vehicle interior temperature and determines a cooling capability of the cooling unit necessary to maintain the vehicle interior temperature at a set temperature. In addition, only at the beginning of heating operation,
An initial cooling unit for increasing the cooling capacity of the air by the cooling unit is provided.

It should be noted that the heating operation results in raising the indoor temperature, regardless of whether or not the cooling means is operating.

[Operation] When the heating operation is started, the initial cooling means of the control circuit increases the cooling capacity of the cooling means for a while after the start of heating, regardless of the possibility of fogging of the window glass.

When the cooling capacity of the cooling means increases, the dehumidifying ability of the air blown into the vehicle compartment increases, and the humidity in the vehicle compartment decreases.

For this reason, at the beginning of the heating operation, the temperature inside the vehicle compartment rises due to the heating operation, and even if the room temperature is higher than the temperature of the inner surface of the window glass, the defrosting effect of the cooling means causes the fogging of the window glass. Is prevented.

After a certain time has elapsed since the start of the heating operation, the temperature of the surface inside the window glass approaches the temperature in the vehicle interior. That is, since the inner surface of the window glass substantially matches the temperature in the vehicle interior, the interior of the window glass does not fog regardless of the humidity in the vehicle interior.

After a certain period of time has elapsed since the start of the heating operation, the control circuit reduces the cooling capacity, so that the power consumed by the cooling means can be kept low.

[Effects of the Invention] As described above, the present invention can suppress the fogging of the windowpane and reduce the power consumption of the cooling means.

Embodiment Next, a vehicle air conditioner of the present invention will be described based on an embodiment shown in the drawings.

 FIG. 1 is a schematic configuration diagram of a vehicle air conditioner.

The vehicle air conditioner 1 includes a duct 2 for sending air toward a vehicle interior. Upstream of this duct 2,
An inside air inlet 3 for circulating vehicle interior air and an outside air inlet 4 for introducing outside air into the vehicle interior are formed. The openings of the inside air inlet 3 and the outside air inlet 4 are adjusted by the inside / outside air switching damper 5.

Inside the duct 2, a blower 6, a cooling unit 7, and a heating unit 8 are sequentially arranged from upstream to downstream, and the air that has passed through the heating unit 8 is blown out from each outlet 9 into the vehicle interior.

The blower 6 generates an airflow in the duct 2 and blows the airflow into the air cabin sucked from the inside air inlet 3 or the outside air inlet 4.

The cooling means 7 is a refrigerant evaporator of the cooling cycle 10 in this embodiment. The refrigeration cycle 10 is a well-known type that includes a cooling compressor 11, a refrigerant condenser 12, and a pressure reducing device 13 in addition to a refrigerant evaporator, and is connected by a refrigerant pipe 14. As the refrigerant compressor 11 of the present embodiment, a variable displacement compressor capable of changing the compression capacity of the refrigerant is used. That is, the cooling means 7
Is changed by controlling the compression capacity of the refrigerant. In addition, the variable capacity type refrigerant compressor
As an example of the eleventh type, for example, a type in which the inclination angle of a swash plate is changed is known.

The heating means 8 includes a heater core 15 that uses the cooling water of the engine as a heat source, and a bypass passage that bypasses the heater core 15.
16, an air mix damper 17 for adjusting the ratio of the air passing through the heater core 15 to the air passing through the bypass passage 16. By changing the opening of the air mix damper 17, the amount of air passing through the duct 2 changes,
As a result, the heating capacity of the air changes. The air mix damper 17 is driven by, for example, an electric motor 18. The circulation of cooling water (hot water) to the heater core 15 is as follows.
Controlled by the water valve 19.

The blowing capacity of the blower 6, the refrigerant compression capacity of the refrigerant compressor 11, the opening degree of the air mix damper 17, and the like described above are controlled by the control circuit 20 using a computer. The control circuit 20 includes, as means for detecting the state of the vehicle, an outside air temperature sensor 21 for detecting the outside air temperature, a solar radiation sensor 22 for detecting the amount of solar radiation, a room temperature sensor 23 for detecting the indoor temperature, and a cooling means 7.
And a water temperature sensor 25 for detecting the temperature of the cooling water flowing into the heater core 15. The control circuit 20
The vehicle includes an operation switch 26 operated by a vehicle occupant, a temperature setting device 27 for setting a target indoor temperature, and the like.

When the operation switch 26 is turned on, the computer of the control circuit 20 calculates a cooling capacity according to the state of the vehicle detected by various sensors, and includes a cooling capacity determining means 28 for determining the cooling capacity of the cooling means 7. In addition, the computer of the control circuit 20 includes an initial cooling unit 29 that activates the cooling unit 7 when the operation switch 26 is turned on, that is, at an early stage when the operation is started. The initial cooling means 29 of the present embodiment is
If there is a possibility that fogging will occur in 30, the refrigerant compressor 11
To increase the refrigerant compression capacity and increase the dehumidifying effect.

Next, the operation of the cooling capacity determining means 28 and the initial cooling means 29 will be described with reference to the flowchart of FIG.

First, in step S1, each signal is input. Specifically, the set temperature Tset, the indoor temperature Tr, the outside air temperature Tam,
The solar radiation amount Ts, the evaporator outlet temperature Te, and the cooling water temperature Tw are read.
Next, in step S2, a transient term Td is calculated. The transient term Td is a heat load required to bring the room temperature close to the target temperature, and is obtained by the following equation.

Td = − | (Tset−Tr) Kr | (Kr indicates a coefficient set according to the vehicle to be mounted.) Subsequently, in step S3, a steady term Ts is calculated.
The stationary term Ts is a heat load required to maintain the set temperature Tset, and is obtained by the following equation.

Ts = (Kr−Kset) Tset−Kam · Tam−Ks · Ts + C (Kset, Kam, Ks, and C indicate coefficients and constants set according to the mounted vehicle.) Then, in step S4. , The transient term Td and the steady term Ts are added to determine the required blowing temperature TAO.

Then, in step S5, the evaporator outlet temperature sensor 24
The control of the capacity of the refrigerant compressor 11 is performed such that the detected evaporator outlet temperature Te becomes the required blowing temperature TAO, and then the process returns.

The heating of the blown air by the heating means 8 and the control of the air volume are performed in a routine independent of the above control, and an example thereof is shown in the flowchart of FIG.

First, in step S6, signals such as a set temperature Tset, a room temperature Tr, an outside air temperature Tam, an amount of solar radiation Ts, an evaporator outlet temperature Te, and a cooling water temperature Tw are read. Next, in step S7, the required blowing temperature TAO is calculated from the read signal using the following equation.

TAO = Kset · Tset−Kr · Tr−Kam · Tam−Ks · Ts + C Next, in step S8, control of the inlet, control of the outlet, control of the air volume, and other controls are performed. Then, in step S9, the heating capability of the air by the heating means 8 is controlled. Specifically, the opening SW of the air mix damper 17
Is determined by the following equation, and the amount of air heated by the heater core 15 is controlled.

 SW = (TAO-Te) / (Tw-Te) Then, after execution of step S9, the process returns.

 Next, the operation of the above embodiment will be briefly described.

B) When the room temperature Tr is higher than the set temperature Tset, the cooling operation is performed. During the cooling operation, the required blowing temperature TAO calculated by the control circuit 20 is low. Therefore, the required outlet temperature TAO is set to the evaporator outlet temperature Te by the variable displacement control of the refrigerant compressor 11 (TAO = Te). As a result, the opening degree SW of the air mix damper 17 becomes O, and the air mix damper 17 is maintained in the maximum cool state. In other words, during cooling operation,
The outlet temperature is controlled only by the variable displacement control of the refrigerant compressor 11, and the air that has passed through the cooling means 7 is blown into the vehicle interior without being heated by the heater core 15.

When the room temperature is higher than the set temperature Tset at the beginning of the cooling start and the temperature difference is large, the cooling capacity by the transient term Td increases as shown in the flowchart of FIG. After a while from the start of cooling operation,
The indoor temperature Tr and the set temperature Tset approach. Then, the transient term
The cooling capacity due to Td is small or lost, and the steady term
The cooling capacity is determined by Ts.

B) When the room temperature Tr is lower than the set temperature Tset, the heating transient operation is performed. During the heating operation, the required blowing temperature TAO calculated by the control circuit 20 is high. For this reason, the refrigerant compressor 11
By the control of the refrigerant compression container, the evaporator outlet temperature Te does not reach the required blowing temperature TAO even if the refrigerant compression capacity becomes minimum (TAO ≠ Te). For this reason, the opening degree SW of the air mix damper 17 is calculated and controlled by the control circuit 20, and the amount of air heating is adjusted by adjusting the opening degree of the air mix damper 17, thereby controlling the blowing temperature.

A case where the room temperature Tr is lower than the set temperature Tset at the beginning of heating and the temperature difference is large will be described. At the beginning of heating, the surface temperature of the window glass 30 on the indoor side is low, and the air heated by the vehicle air conditioner 1 is supplied to the vehicle interior. Then, fogging is about to occur on the surface of the window glass 30. However, in the present embodiment, when the difference between the room temperature Tr and the set temperature Tset is large at the beginning of heating, the cooling capacity is increased by the transient term Td as shown in the flowchart of FIG. When the cooling capacity increases, the dehumidifying ability of the air blown into the vehicle compartment increases, and the humidity in the vehicle compartment decreases.

For this reason, at the beginning of the operation start of the vehicle air conditioner 1,
Even if the room temperature Tr rises due to heating of the vehicle air conditioner 1 and the temperature of the surface of the window glass 30 on the vehicle interior side is low, the dehumidifying effect of the cooling means 7 prevents the fogging of the window glass 30 from occurring. It is.

Some time after the start of the operation of the air conditioner 1 for a vehicle, the indoor temperature Tr rises due to the heating operation, and the window glass
The temperature of the surface on the interior side of the vehicle 30 approaches the interior temperature Tr. That is, the interior surface of the window glass 30 substantially coincides with the interior temperature Tr, so that the window glass 30 does not become cloudy regardless of the humidity in the interior of the vehicle. Note that the time after the start is greatly different depending on the environment of the vehicle. The lower the environmental temperature, the longer the time.

On the other hand, the room temperature Tr approaches the set temperature Tset with the lapse of time accompanying the operation of the vehicle air conditioner 1. As the temperature approaches, the cooling capacity of the air due to the transient term Td decreases. As a result, the compression capacity of the refrigerant compressor 11 decreases, and the power consumption of the refrigerant compressor 11 can be reduced.

(Effects of Embodiment) As described above, according to this embodiment, when fogging is likely to occur in the window glass 30 at the beginning of the heating exercise, dehumidification is performed to suppress the fogging of the window glass 30. . When heating progresses and the possibility of fogging of the window glass 30 decreases,
The refrigerant compression capacity of the refrigerant compressor 11 is reduced,
The power consumption of 11 is kept low.

(Modification) In the present embodiment, the initial cooling means for increasing the cooling capacity at the beginning of the operation start in the heating operation using the characteristics of the transient term during heating is configured. For example, instead of using the transient term, When the operation switch is turned on, using a timer or the like to configure the initial cooling means to increase the capacity of the variable displacement type refrigerant compressor at a predetermined time to increase the cooling capacity, and to use other structures using the initial cooling means. Is also good. If you give a specific example,
As shown in the flowchart of FIG.
When it is turned on, regardless of the heating operation or the cooling operation, a variable capacity refrigerant compression is performed so that the required blow-out temperature of the cooling means becomes 3 ° C., which is the frost limit, for a predetermined time (for example, 1 to 10 minutes) immediately after the start of operation. Control the capacity of the machine. Then, after a lapse of a predetermined time, the cooling capacity is controlled based on the vehicle state such as the outside air temperature, the amount of solar radiation, and the indoor temperature to reduce the power applied to the refrigerant compressor.

Although the cooling capacity is controlled by changing the compression capacity of the refrigerant compressor, the cooling capacity may be controlled by controlling the energization time of the electromagnetic clutch.

Although the refrigerant evaporator has been described as an example of the cooling unit, other cooling units such as a cooling unit of a refrigeration cycle using air compression and expansion, and a cooling unit using a Peltier element may be used.

Although a heater core that circulates cooling water is shown as an example of the heating means, other heating means such as a PTC heater or a combustion heater may be used.

[Brief description of the drawings]

1 to 3 show a first embodiment, FIG. 1 is a schematic diagram of an air conditioner, FIG. 2 is a flowchart showing an example of the operation of cooling capacity determining means and initial cooling means,
FIG. 3 is a flowchart showing an example of an operation such as air volume control. FIG. 4 is a flowchart showing a modification of the initial cooling means. FIG. 5 is a schematic configuration diagram of the present invention. In the figure, 1 ... Vehicle air conditioner, 2 ... Duct, 6 ...
... blower, 7 ... cooling means, 8 ... heating means, 20 ... control circuit, 28 ... cooling capacity determination means, 29 ... initial cooling means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B60H 1/00 101

Claims (1)

(57) [Claims] 1. A duct for sending air toward a passenger compartment, a blower for generating an airflow toward the passenger compartment in the duct, and a cooling device disposed in the duct for cooling air blown into the passenger compartment. A heating unit disposed in the duct downstream of the cooling unit to heat air blown into the vehicle interior; controlling a cooling capacity of the air by the cooling unit and a heating capability of the air by the heating unit. A control circuit for controlling the temperature of the cabin to a set temperature, wherein the control circuit detects a vehicle state such as a cabin outside temperature, a cabin temperature, and sets the cabin temperature. Along with cooling capacity determining means for determining the cooling capacity of the cooling means necessary to maintain the temperature, only at the beginning of the heating operation, the cooling capacity of the air by the cooling means Air conditioning apparatus for a vehicle, characterized in that it comprises an initial cooling means for listening.