JP2663699B2 - Vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner having a blower fan and an evaporator.

B. Conventional technology A vehicle air conditioner that includes a blower fan and an evaporator that cools air from the blower fan and controls the air flow rate of the blower fan according to the vehicle heat load (for example, the outside air temperature and the amount of solar radiation) has been conventionally used. (Eg, “Service Bulletin” No. 578 (June 1987) issued by Nissan Motor Co., Ltd.).

C. Problems to be Solved by the Invention However, immediately after operating the air conditioner, the cooling capacity of the evaporator is not sufficient, and if the air volume of the blower fan is large, the air cannot be sufficiently cooled by the evaporator, The outlet temperature increases, and as a result,
There was a problem of discomfort to the occupants.

An object of the present invention is to provide an air conditioner for a vehicle that prevents discomfort due to a high outlet temperature.

D. Means for Solving the Problems Referring to FIG. 1 which is a diagram corresponding to the claims, the present invention provides a blower fan 101, a driving means 102 for driving the blower fan 101, and cooling of air from the blower fan 101. The present invention is applied to an air conditioner for a vehicle including an evaporator 103 for controlling the air flow of a blower fan 101 in accordance with the heat load of the vehicle.
The above problem is solved by providing a suction temperature sensor 105 for detecting a suction temperature downstream of the evaporator 103 and an indoor temperature sensor 106 for detecting a vehicle interior temperature, and configuring the air volume control means 104 as follows. .

That is, when the vehicle interior temperature is lower than the predetermined temperature and the suction temperature exceeds the predetermined value, the air volume control unit 104 controls the driving unit 102 to reduce the blower fan air volume below normal according to the suction temperature.

E. Function When the vehicle interior temperature is lower than the predetermined temperature and the suction temperature exceeds the predetermined value, the air volume of the blower fan 101 is reduced more than usual according to the suction temperature (air temperature downstream of the evaporator 103). As a result, when the cooling capacity of the evaporator 103 is not sufficient, the air volume of the blower fan 101 is reduced, and the air volume is reduced to such an extent that the occupant does not feel uncomfortable due to the reduction of the air volume. When the vehicle interior temperature is equal to or higher than the predetermined temperature, the normal air volume is used to increase the cooling capacity.

In the above sections D and E for describing the configuration of the present invention, the drawings of the embodiments are used for easy understanding of the present invention, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 2, a vehicle air conditioner according to the present invention is a cooler of a compression refrigeration cycle including a variable displacement compressor 2, a condenser 3, an evaporator 4, a liquid tank 5, and an expansion valve 6 driven by an engine 1. Unit 100
It has. When the suction pressure exceeds a set pressure, the variable displacement compressor 2 increases the tilt angle to increase the discharge capacity. The set pressure is controlled by the CPU 41 shown in FIG.
Controlled by the solenoid current I _SOL supplied from the Further, the evaporator 4 is disposed in an air conditioning duct 7 having an outside air inlet 7a and an inside air inlet 7b.

Inside and outside air switching doors 8 for controlling the flow rate of air introduced into the air conditioning duct 7 are provided at each of the inlets 7a and 7b. Further, in the air conditioning duct 7, a blower fan 9, a heater unit 10, and an air mixing door 11 are provided as is well known, and the amount of air blown from a vent outlet 7c and a foot outlet 7d provided in the air conditioning duct 7 is respectively controlled. A vent door 12 and a foot door 13 to be adjusted are provided. Further, a defroster door 14 is provided at a defroster outlet 7e provided in the air conditioning duct 7.

The bend outlet 7c is for blowing air toward the upper body of the occupant, the underfoot outlet 7d is for blowing air toward the occupant's feet, and the defroster outlet 7e is for blowing air toward the window glass. It is for blowing out. After the air from the blower fan 9 is cooled by the evaporator 4, the air is blown into the passenger compartment from each outlet.

FIG. 3 is a block diagram showing a control system of the vehicle air conditioner according to the present invention. An external temperature sensor 43 for detecting an outside air temperature T _AMB and a vehicle interior temperature T _INC
Room temperature sensor 44 for detecting a solar radiation sensor 45 detects a solar radiation amount Q _SUN, suction temperature sensor 46 for detecting the air temperature (inlet temperature) T _INT downstream of the evaporator 4 is connected, from the sensors 43 - 46 Various temperature information and calorie information
Is input to

Further, to the input circuit 42, an ignition switch 51 is connected, and a defroster switch 52, an air volume setting switch 53, and an off switch 54 provided on a control panel of a driver's seat are connected. The defroster switch 52 is a switch for commanding a differential mode (mainly a mode for blowing air from the defroster outlet 7e), and the air volume setting switch 53 is a switch for manually commanding the air volume of the blower fan 9. In this embodiment, the air volume setting switch 53
, The first, second and third speeds can be selected. The off switch 54 is a switch that is turned on when the operation of the blower fan 9 is stopped.

Further, an air mix door actuator 61, a vent door actuator 62, a foot door actuator 63, a defroster door actuator 64, and a blower fan control circuit 65 are connected to the CPU 41 via an output circuit 49, and the blower fan control circuit 65 Motor that drives 9
9a is connected. The output circuit 49 further includes a relay 66
Is connected to the compressor 2 via the.

Next, the procedure of control by the CPU 41 will be described based on the flowcharts of FIGS.

FIG. 4 is a flowchart showing the basic control of the air conditioning control device executed by the CPU 41.

When the ignition switch 51 is turned on, the program is started.In step S10, initial setting is performed.In the normal auto air conditioner mode, for example, the set temperature T _PTC is set.
Initially set to 25 ° C. In step S20, various information from each sensor or switch is input.

To explain these data information concretely, set temperature
T _PTC is _calculated from the control panel (not shown)
_INC is from the indoor temperature sensor 44, the outside air temperature T _AMB is from the outside air temperature sensor 43, the solar radiation amount Q _SUN is from the solar radiation sensor 45, and the suction temperature.
T _INT is provided from the suction temperature sensor 46.

Next, in step S30, the outside air temperature _TAMB obtained from the outside air temperature sensor 43 is processed to a value _TAM corresponding to the actual outside air temperature, excluding the influence from other heat sources. Then step S
At 40, the solar radiation amount information as the amount of light from the solar radiation sensor 45 is processed into a value Q ' _SUN as a heat amount suitable for subsequent conversion.
In step S50, the set temperature T _PTC set on the control panel is processed to a value T ′ _PTC corrected according to the outside air temperature.

In step S60, the target outlet temperature T _O is calculated from T _INC , T _AM , Q ′ _SUN (these correspond to the vehicle thermal load) and T ′ _PTC , and the target outlet temperature T _O and the actual outlet temperature are calculated. The air-mix door 11 is controlled by the air-mix door actuator 61 in accordance with the deviation of the air temperature and the blow-out temperature is controlled.
In step S70, the compressor 2 is controlled. Step S
In 80, the doors 7c, 7d, 7e are driven by the vent door actuator 62, the foot door actuator 63, and the defroster door actuator 64 based on the target outlet temperature T _O to control the outlet.

In step S90, selection switching of the suction port, that is, the outside air introduction port 7a and the inside air introduction port 7b is controlled. In step S100, by controlling the blower fan 9 as described later,
Controls the air volume from the outlet. After that, the process
Returning to S20, the above processing is repeated.

FIG. 5 is a flowchart showing details of the air volume control in step S100 described above.

In FIG. 5, first, in step S101, the off switch 54
Is determined. If the off switch 54 is on, the blower fan 9 is stopped in step S102. If the off switch 54 is off, it is determined in step S103 whether the air volume setting switch 53 is operated. If it has been operated, proceed to step S104,
Hereinafter, the applied voltage to the blower fan motor 9a is determined according to the operation state.

That is, if the first speed is instructed, step S104 is affirmed, and the applied voltage is set to V1 in step S106. If the two speeds have been commanded, step S105 is affirmed, and the applied voltage is set to V2 (V2> V1) in step S107. If 3 speeds have been further commanded, step S105 is denied and step
In S108, the applied voltage is set to V3 (V3> V2). And step
In S109, the application voltage determined above is applied to the blower fan motor 9a via the blower fan control circuit 65. Thereby, the blower fan 9 is driven at a speed (air volume) according to the applied voltage.

On the other hand, if it is determined in step S103 that the air volume setting switch 53 has not been operated, the process proceeds to step S110, and it is determined whether the defroster switch 52 is on. If it is off, the process proceeds to step S112. If it is on, the constants L, M, N, and P are changed in step S111, and the process proceeds to step S112. That is, these constants L, M, N, and P are set to predetermined values in advance, but are changed when the defroster switch 52 is operated.

In step S112, it is determined whether the vent mode (mainly, the mode in which air is blown out from the vent outlet 7c) is set by the outlet control in step S80, and if negative, the process proceeds to step S114 and is affirmed. that the variable from the characteristics shown in accordance with the correction value Q _'SUN of insolation in step S113 beta
Is determined and the process proceeds to step S114. In step S114, the voltage Vf is determined from the illustrated characteristics according to the target outlet temperature T _O and the constants L, M, N, P, and the process proceeds to step S115. Steps
In step S115, a variable α is determined from the characteristics shown in the figure according to the correction value T _AM of the outside air temperature.
Find Vf '.

In the vent mode: Vf '= 5 + β + (Vf−5−β) × α In the case other than the vent mode: Vf ′ = 6 + β + (Vf−6) × α Here, β in the vent mode is based on the characteristics of step S113. It is the value obtained, β in other than vent mode
Is a preset value.

Next, the process proceeds to step S117, and it is determined whether or not the room temperature T _INC is lower than 30 ° C. If this is denied, the process proceeds to step S120, where the calculated voltage Vf 'is set as the applied voltage Vf ″, and the process proceeds to step S121. If affirmed, the suction temperature is determined in step S118.
Determine if T _INT is below 15 ° C. When step S118 is affirmed, the process proceeds to step S120. When denied, that is, when the suction temperature exceeds a predetermined value, step S119 is performed.
Vf ″ = Vf′−α (T _INT −15) (1) The applied voltage Vf ″ is obtained from the following equation, and the process proceeds to step S121. In step S121, the applied voltage Vf ″ obtained in step S120 or S119 is applied to the blower fan motor 9a via the blower fan control circuit 65, and the blower fan 9 is driven at a speed (air volume) according to the voltage Vf ″. Drive.

According to the above procedure, Vf ′ is determined based on the voltage Vf obtained from the target outlet temperature T _O and the constants α and β, and in a normal case (the vehicle interior temperature is 30 ° C. or more or the suction temperature is 15 ° C.).
Is exceeded, this Vf 'is applied to the blower fan motor 9a as the applied voltage Vf ", and the blower fan air volume is determined.

On the other hand, when the vehicle interior temperature is lower than 30 ° C. and the suction temperature exceeds 15 ° C., the applied voltage Vf ″ is determined by the above equation (1). According to this equation (1), the suction temperature T _INT Is higher, the applied voltage Vf ″ is smaller, and the blower fan airflow is reduced. That is, when the cooling capacity of the evaporator 4 is not sufficient, the air volume of the blower fan is reduced accordingly, and the rise in the blowout temperature is suppressed.
Eliminates discomfort to the occupants.

The reason why the normal air volume control is performed when the room temperature is 30 ° C. or higher is to quickly cool the vehicle interior.

In the configuration of the above embodiment, the CPU 41 and the blower fan control circuit 65 constitute the air volume control unit 104.

Note the applied voltage Vf "equation for is not limited to (1), the inlet temperature T as _INT is high applied voltage Vf" as long as it is smaller, or in other forms.

G. Effects of the Invention According to the present invention, when the vehicle interior temperature is lower than the predetermined temperature and the suction temperature exceeds the predetermined value, the blower fan air volume is reduced more than usual according to the suction temperature, When the cooling capacity of the evaporator is not sufficient, the air volume of the blower fan is reduced, the rise in the blow-out temperature is suppressed, and the occupant does not feel uncomfortable.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims. 2 to 5 show an embodiment of the present invention. FIG. 2 is a general configuration diagram of a vehicle air conditioner according to the present invention, FIG. 3 is a block diagram showing a control system, and FIG. FIG. 5 is a flowchart for explaining the details of the air volume control. 4: Evaporator, 9: Blower fan 9a: Blower fan motor, 41: CPU 43: Outside air temperature sensor, 44: Indoor temperature sensor 45: Solar radiation sensor, 46: Suction temperature sensor 65: Blower fan control circuit 101: Blower fan, 102 : Drive means 103: Evaporator, 104: Air volume control means 105: Suction temperature sensor, 106: Indoor temperature sensor

Claims (1)

(57) [Claims] A blower fan; a drive means for driving the blower fan; an evaporator for cooling air from the blower fan; and a drive means for controlling an air volume of the blower fan according to a vehicle thermal load. An air conditioner for a vehicle, comprising: a control unit for controlling an air flow rate; a suction temperature sensor for detecting a suction temperature downstream of an evaporator; and an indoor temperature sensor for detecting a vehicle interior temperature. When the temperature is lower than a predetermined temperature and the suction temperature exceeds a predetermined value, the driving unit is controlled to reduce the blower fan air volume below normal according to the suction temperature. apparatus.