JPH0138684B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner for an automobile.

[Prior Art] An automobile air conditioner equipped with a refrigerant evaporator (cooler) and a heater has a drawback that the blowout temperature changes rapidly as the refrigerant compressor is driven and stopped.
In addition, the blowout temperature also changes when the intake air is switched between inside air (cabin air) or outside air, and especially when there is a large temperature difference between inside air and outside air, the change in the blowout temperature is extreme and can be extremely uncomfortable. There are drawbacks.

In order to solve these drawbacks, the refrigerant compressor is started and stopped when the outside air temperature is around 0°C, and the outside air is always used as intake air when the outside air temperature is around 0°C. A method has been proposed in which the temperature of the air that has passed through the refrigerant evaporator is maintained at around 0° C., regardless of the temperature, to reduce sudden changes in the blowout temperature.

According to this conventional technology, the temperature of the refrigerant evaporator is maintained at around 0°C by a known method, so sudden changes in the blowout temperature can be suppressed, but when the outside air temperature is 0°C.
Driving a refrigerant compressor even in this environment wastes power and is difficult to adopt from the standpoint of energy conservation. In addition, since using outside air as the intake air is a requirement to reduce changes in the outlet temperature, for example, when you want to switch the intake air to inside air to prevent the infiltration of exhaust gas from a preceding vehicle, it is necessary to For example, the air may switch from outside air at around 0°C to inside air at around 24°C. In this case, the engine cooling water flowing through the heater is kept at a temperature of around 80°C, but if the temperature of the intake air changes significantly, the blowout temperature will also rise to 20°C.
The temperature also fluctuated around ℃, giving an extremely unpleasant sensation.

Conventionally, as a technology to solve such problems,
For example, there is one disclosed in Japanese Patent Publication No. 53-33814. According to this prior art, the opening degree of the air mix damper is corrected based on the operating state of the refrigerant compressor and the temperature of the intake air, thereby suppressing fluctuations in the blowout temperature. However, since the air mix damper is driven by a negative pressure actuator, it is not only large in size, but also has to be equipped with a negative pressure tank, making it difficult to install these in a limited space. This is difficult for small vehicles.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the purpose of the present invention is to solve the problem in that the blowout temperature does not change significantly even when the refrigerant compressor is started or stopped, or even when the intake air is switched to inside air or outside air. It is an object of the present invention to provide an economical air conditioner for an automobile that is small in number and does not require an extra temperature sensor.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention includes an air mixer that includes at least an inside air temperature sensor and a cabin temperature setting device, and that opens and closes a heater based on these signals. In automobile air conditioners that drive dampers to control the outlet temperature, the air conditioning switch
The rotation correction amount of the electric motor that detects ON/OFF signals and drives the air mix damper is made larger as the opening degree of the air mix damper becomes smaller, and becomes smaller as the opening degree of the air mix damper becomes larger.

[Operation] Signals from the inside air temperature sensor and the vehicle interior temperature setting device 31 are added and differentially amplified in the operational amplifier 27, and are applied to the − input terminal of the operational amplifier 28. On the other hand, the opening degree of the air mix damper 36 or the rotational position of the electric motor 36a for driving the air mix damper is detected by the resistor 18, and this signal is applied to the + input terminal of the operational amplifier 28.

In the operational amplifier 28, a voltage based on the inside air temperature and a voltage based on the opening degree of the air mix damper are differentially amplified, and this output signal drives the air mix damper which opens and closes the heater.

The gain of operational amplifier 28 is determined by resistors 11 and 12. A transistor 34 is connected to both terminals of the resistor 12, and a predetermined voltage is applied to the base of the transistor 34 while the refrigerant compressor is in operation, making the transistor 34 conductive.

When the air conditioning switch is turned on and off (driving and stopping the refrigerant compressor), this signal is detected and the rotational position of the electric motor that drives the air mix damper, that is, the opening degree of the air mix damper, is corrected to prevent a sudden rise in the blowout temperature. changes can be suppressed.

[Examples of the Invention] The present invention will be described based on Examples. As shown in FIG. 5, the air conditioner includes an inside air intake 61 and an outside air intake 62 that are opened and closed by an inside/outside air switching shutter 63 at the starting end of a case 66 that forms a heat exchange chamber. It includes a blower 39 driven by an electric motor, a refrigerant evaporator 65, an air mix damper 36, and a side passage 68, and is biased to one side.
In addition, heaters 69 using engine cooling water as a heat source are sequentially arranged, and the terminal end of the case 66 is formed as a duct, with a cold air (upper) outlet 71 opened and closed by a shutter 70 branched off in the middle, and a It is configured with a defrost outlet 72 and a warm air (downward) outlet 74 which are switched by a switching shutter 73. The shutters 63, 70, 73 and the air mix damper 67 are each driven by electric motors.

As shown in FIG. 2, driving and stopping of the refrigerant compressor 50 that supplies refrigerant to the refrigerant evaporator 65 and the case 66 from the inside air intake port 61 or the outside air intake port 62 are performed.
Electric motor 39a of the blower 39 that sucks air taken into the
is controlled by an electronic control device 47. That is, when the air conditioning switch 45 is closed, the movable contact pieces 43 and 41 are rotated in conjunction with each other according to the temperature difference between the temperature of the blown air and the set temperature of the blown air. Therefore, the relay coil 48 is excited by the output signal from the temperature control amplifier 46 based on this temperature difference, the switch 49 is closed, and the refrigerant compressor 50 is driven. In addition, the movable contact piece 41 of the blowout amount regulator 40
As is rotated clockwise, the resistors 53,5
2 and 51 are sequentially removed from the energizing circuit of the electric motor 39a of the blower 39, the number of rotations increases, and the air volume increases. Such a configuration is almost the same as the conventional one, and since it is not directly related to the gist of the present invention, it will not be described further.

According to the present invention, as shown in FIG. 1, the rotational position of the electric motor 36a that drives the air mix damper 36 (the opening degree of the air mix damper 36) determines whether the intake air is outside air or inside air. Regardless of whether the refrigerant compressor is activated or stopped, the system is configured so that the blowout temperature is maintained at the set temperature by quickly controlling the refrigerant compressor.

In the electrical circuit diagram shown in Fig. 1, 33 is a power supply battery, 1 to 18, 20 to 26 are resistors, in particular, resistor 17 is a resistor (potentiometer) for manually setting the blowing temperature, and 18 is an air mix damper. 36
This is a resistance that detects the opening degree of the air mix damper 36 or the rotational position of the electric motor 36a that drives the air mix damper 36.
27 and 28 are operational amplifiers, 29 and 30 are comparison amplifiers, 31 is an inside air temperature sensor consisting of a thermistor, etc., 32 is a similar outside air temperature sensor, 34 is a transistor, and 35 is the rotation of an electric motor 36a that drives the air mix damper 36. a control device for controlling, 38
is a diode.

Next, the operation of the automotive air conditioner according to the present invention will be explained. The power supply voltage Vt divided by the combined resistance indicated by the inside air temperature sensor 31 and the outside air temperature sensor 32 and the resistor 1 passes through the resistor 5 to the operational amplifier 27.
is applied to the − input terminal of On the other hand, the power supply voltage divided by the resistors 3 and 4 is applied to the + input terminal of the operational amplifier 27 via the resistor 6 as the reference voltage Vs. Furthermore, the power supply voltage divided by the resistor 17 of the cabin temperature setting device B, which is manually set, is applied to the - input terminal of the operational amplifier 27. These input signal voltages are added and differentially amplified in the operational amplifier 27, outputted as an output voltage Vo, and applied to the - input terminal of the operational amplifier 28 via the resistor 9.

On the other hand, a bridge circuit is constituted by a resistor 18 that detects the opening degree of the air mix damper 36 or the rotational position of the electric motor 36a for driving the air mix damper, and resistors 22 and 23 connected in series with the power supply. , resistors 20 and 21 are connected in series between the movable contact of resistor 18 and the connection point of resistors 22 and 23,
Voltage V6 at the connection point between resistors 20 and 21 is applied via resistor 10 to the +input terminal of operational amplifier 28.

In the operational amplifier 28, the above-mentioned set temperature,
A voltage Vo based on the inside air temperature and outside air temperature and a voltage V6 based on the opening degree of the air mix damper are added and differentially amplified to generate an output voltage V2.
The gain of operational amplifier 28 is determined by resistors 11 and 12. In order to short-circuit the resistor 12, a transistor 34 is connected to both terminals of the resistor 12, and a predetermined voltage is applied to the base of the resistor 34 while the refrigerant compressor is in operation, making the transistor 34 conductive. That is,
0 volt is applied to the terminal 54 when the refrigerant compressor is stopped, and a predetermined voltage Vc is applied when the refrigerant compressor is driven.
It is added to the connection point of resistors 24 and 25 connected in series to the power supply through a diode 38, and is further connected to a resistor 26.
to the base of transistor 34.
In this way, the output voltage V2 amplified by the predetermined gain in the operational amplifier 28 is
It is applied to the input terminal and the − input terminal of the comparator amplifier 30, respectively.

On the other hand, the reference voltage V3 divided by the resistors 13 and 14 passes through the resistor 15 to the comparator amplifier 29.
A comparator amplifier 30 is connected to the input terminal and via a resistor 16.
are added to the + input terminals of each. A signal voltage for increasing or decreasing the opening degree of the air mix damper is transmitted from the comparison amplifiers 29 and 30 to the control device 3.
5, and the output signal from the control device 35 causes the air mix damper driving electric motor 36a to rotate forward or reverse by a predetermined amount of rotation. Electric motor 3
When motor 6a is driven, the amount of rotation is detected by detector C, this detection signal voltage V6 changes, and when output voltage V2 of operational amplifier 28 becomes equal to reference voltage V3, motor 36a stops.

As mentioned above, when the refrigerant compressor is driven, the transistor 34 is conductive and the resistor 12 is shorted, so that the gain of the operational amplifier 28 is reduced,
Signal voltage Vo that drives the air mix damper 36
The relationship between the signal voltage Vr for detecting the opening degree of the air mix damper and the opening degree of the air mix damper is shown by the solid line in FIG.

On the other hand, when the refrigerant compressor is stopped, the transistor 34 becomes non-conductive and the resistor 12 is added to the feedback circuit of the operational amplifier 28, resulting in an increase in gain and the relationship between the voltages Vo and Vr becomes
It changes as shown by the chain line in the figure. As a result, the rotation amount (reverse rotation) of the electric motor 36a is increased, the opening degree of the air mix damper 36 is significantly reduced, and the amount of air passing through the heater is significantly reduced, so that the blowout temperature due to the stoppage of the refrigerant compressor is reduced. A sudden rise in temperature is suppressed, and the blowing temperature is kept constant.

Conversely, when the refrigerant compressor is driven, the gain of the operational amplifier 28 decreases, the balance between the output voltage V2 and the reference voltage V3 is lost, the electric motor 36a is rotated forward, and the opening degree of the air mix damper 36 is reduced. increased,
The amount of air sent to the heater increases, suppressing a sudden drop in the blowout temperature.

When the refrigerant compressor is driven, the cooling capacity of the refrigerant evaporator does not increase rapidly, so as is clear from the characteristics shown by the solid line in FIG.
The rotation correction amount a is smaller than the rotation correction amount when the refrigerant compressor is stopped, and the opening degree of the air mix damper 36 is increased as the cooling capacity of the refrigerant evaporator increases.

In addition, in the above-mentioned embodiment, the refrigerant evaporator is driven and
The feedback resistor 12 of the operational amplifier 28 was configured to be short-circuited or connected based on the stoppage, but as shown in FIG. When the refrigerant compressor is driven, the switch 37 is closed and this resistance 19 is
A similar effect can be obtained even if the signal voltage V6 applied to the + input terminal of the operational amplifier 28 is changed by short-circuiting.

[Effects of the Invention] As described above, the present invention performs a calculation using as input a signal based on the temperature difference between the temperature of intake air and the set temperature of blowing air, and a signal for detecting the opening degree of the air mix damper. Since the input signal voltage or feedback resistance of the amplifier is changed in response to driving and stopping the refrigerant evaporator, it is possible to control the driving and stopping of the refrigerant evaporator without installing an expensive temperature sensor. On the other hand, the opening degree of the air mix damper is quickly corrected, a sudden change in the blowing temperature is suppressed, and the temperature can always be maintained almost at the set temperature.

In particular, when the outside temperature is low (when the air mix damper opening is large), the correction amount of the air mix damper changes depending on the opening degree when the refrigerant compressor is started or stopped. The opening correction amount of the air mix damper is small, and when the outside temperature is high (when the air mix damper opening is small), the air mix damper opening correction amount is large. Changes in the blowout temperature due to changes in air temperature can be effectively canceled out, thereby making it possible to maintain the blowout temperature approximately constant.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of an automobile air conditioner according to the present invention, Fig. 2 is an electric circuit diagram for controlling the blower and refrigerant compressor in the automobile air conditioner, and Fig. 3 is an electric circuit diagram for controlling the air blower and refrigerant compressor in the automobile air conditioner. A diagram showing the characteristics of the signal voltage applied to the electric motor for driving the mix damper, FIG. 4 is an electric circuit diagram showing the main parts of the automotive air conditioner according to the second embodiment of the present invention, and FIG. 5 is the general 1 is a schematic configuration diagram of a typical automotive air conditioner. 17: Resistor for setting cabin temperature, 18: Resistor for detecting air mix damper opening, 19: Resistor, 27,2
8: Operational amplifier, 31: Inside air temperature sensor, 32:
Outside air temperature sensor, 33: Power battery, 34: Transistor, 35: Air mix damper drive motor control device, 36: Air mix damper, 3
6a: Electric motor, 37: Switch, 54: Terminal.

Claims (1)

[Claims] 1 In an automotive air conditioner that has at least an inside air temperature sensor and a cabin temperature setting device, and controls the air mix damper that opens and closes the heater based on these signals to control the air outlet temperature,
The feature is that the rotation correction amount of the electric motor that detects ON/OFF signals and drives the air mix damper is increased as the opening degree of the air mix damper becomes smaller, and decreases as the opening degree of the air mix damper becomes larger. Automotive air conditioner.