JPS6344243Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is applicable to air conditioners for automobiles.
This invention relates to an improvement of a device that controls the temperature of blown air by adjusting the opening degree of an air mix door.

(Prior Art) This type of air conditioner for automobiles is known, for example, from Japanese Utility Model Application Publication No. 59-75797 and Japanese Patent Application Publication No. 57-87713, and a specific example thereof is shown in FIG. ing.

That is, in FIG. 3, an air mix door 3 is provided in front of a heater core 2 disposed in an air conditioning case 1, and the opening degree Θ of this air mix door 3 is
Depending on the situation, the proportion of air from a blower (not shown) is adjusted into one that passes through the heater core 2 and one that bypasses it, and these airs are later mixed and blown into the vehicle interior. The blowing air temperature t is determined by the opening degree Θ of the air mix door 3. This air mix door 3 is connected to an output shaft 6 of an actuator 5 via a link mechanism 4.
is connected to. This actuator 5 has a motor 8 that is driven according to the output of a control circuit 7, and the output shaft 6 is moved by this motor 8. Further, this actuator 5 is provided with a potentiometer 9 for detecting the opening degree of the air mix door 3, and this potentiometer 9 has a so-called A material with B characteristic is used.

The control circuit 7 includes a heat load calculation circuit 10, a deviation calculation circuit 11, and a drive circuit 12.
The heat load calculation circuit 10 receives information regarding the air conditioning state inside the vehicle from an air conditioning information source 17 composed of a temperature setting device 13, a vehicle interior temperature sensor 14, an outside air sensor 15, a solar radiation sensor 16, etc. The heat load inside the vehicle is calculated based on the output of the information source 17. Further, the deviation calculation circuit 11 uses the calculated value of the thermal load calculation circuit 10 and the potentiometer 9.
The deviation from the output from t is calculated to determine the temperature to which the blown air temperature t should be corrected. And the drive circuit 12
From there, a drive signal corresponding to the output of the deviation calculation circuit 11 is output to the motor 8, and the opening degree Θ of the air mix door 3 is controlled according to the air conditioning condition in the vehicle interior.

(Problems to be Solved by the Invention) However, in general, the temperature t of the air blown from the heater unit does not vary linearly with the air mix door opening Θ. That is, due to the shape of the duct, the installation position of the heater core 2, etc., as shown in FIG. 4, when the air mix door 3 is close to full hot, the change in the blowing air temperature t relative to the air mix door opening degree Θ becomes rapid.

Therefore, if the correlation between the air mix door opening Θ and the potentiometer 9 is made linear, the control circuit 7 uniformly changes the opening by ΔΘ ₂ in order to increase the outlet air temperature t by Δt ₂ , as shown in the figure. Since it operates to move Θ to the HOT side, the air mix door opening Θ
If Θ is less than ₁ , the target temperature can be obtained, but
In the range of Θ ₁ or more, the temperature change (Δt ₂ ′) of the blown air becomes larger than Δt ₂ , which deviates from the original target temperature, resulting in a problem in which the feeling for the occupants is worsened.

Therefore, as mentioned above, this invention solves the conventional problem that occurs because the control circuit operates as if it changes linearly even though the temperature of the blowing air does not change linearly with the air mix door opening. The objective is to improve the feeling of the occupants by accurately changing the temperature of the blown air to the required temperature.

(Means for solving the problem) However, the most distinctive feature of this invention is that the heat load calculation circuit of the control circuit in the conventional example described above is made to have a polygonal line characteristic of the output voltage with respect to the input voltage. It is constructed using an absolute value circuit.

(Function) Therefore, the output of the potentiometer, which is erroneously detected as if the opening degree of the air mix door is being controlled according to the target characteristics, is input to the deviation calculation circuit, but the thermal load calculation circuit detects the change in the output voltage. Since the circuit is configured to form a polygonal line with respect to the input voltage, this thermal load calculation circuit outputs the result obtained by subtracting the detection error of the potentiometer from the heat load inside the vehicle to the deviation calculation circuit. , the opening degree of the air mix door changes smoothly, and therefore the above object can be achieved.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

An embodiment of this invention is shown in FIG. 1, in which a power source 18 such as an on-board battery has a power line _l1 connected to its positive terminal, and an earth line _l2 connected to its grounded negative terminal. has been done.

The potentiometer 9, which is similar to the conventional example, has one end of its sliding resistance connected to the power supply line _l1 and the other end connected to the earth line _l2 , so that when the air mix door 3 is moved to the heat side ( Opening degree Θ
increases), the mover moves downward to lower the output voltage V _p , and conversely, when the air mix door 3 is moved to the cool side (when the opening degree Θ decreases), the mover moves downward to lower the output voltage V p. The mover moves upward to increase the output voltage V _p .

In addition, the air conditioning information source 17 similar to the conventional example is
For example, a temperature setting device 13, a vehicle interior temperature sensor 14,
An outside air temperature sensor 15 and a solar radiation sensor 16 are connected in series, with the other end of the temperature setter 13 connected to a power supply line _l1 and the other end of the solar radiation sensor 16 connected to an earth line _l2 .

The control circuit 7 is composed of a thermal load calculation circuit 10, a deviation calculation circuit 11, and a drive circuit 12 as in the conventional example, but the configuration of the thermal load calculation circuit 10 is different.

That is, this thermal load calculation circuit 10 has a first operational amplifier 19 and a second operational amplifier 20, and the respective inverting input terminals of the operational amplifiers 19 and 20 are connected to the temperature setting device 13 via resistors 21 and 22. and the connection point between the vehicle interior temperature sensor 14 and the vehicle interior temperature sensor 14 . In addition, a resistor 23 that generates reference voltages V ₁ and V ₂ ,
24 and resistors 25, 26 are connected between the power line _l1 and the earth line _l2 , and the reference voltages _V1 , _V2
is applied to the non-inverting input terminals of the operational amplifiers 19 and 20 via resistors 27 and 28. Further, the output terminals of the operational amplifiers 19 and 20 are connected to the cathodes of diodes 29 and 30, and the anodes of the diodes 29 and 30 are connected to the inverting input terminals of the operational amplifiers 19 and 20 via feedback resistors 31 and 32. It is also connected via a resistor to a third operational amplifier 33 of a deviation calculation circuit 11, which will be described later, to form an absolute value circuit.

Therefore, the gain A ₁ of the first operational amplifier 19,
If the gain of the second operational amplifier 20 is _A2 , the output voltages _{V10ut and V20ut} of the operational amplifiers 19 and 20 with respect to the input voltage _Vio are _V10ut = _-A1 ( _{Vio -V1} )...(1) V _20ut = -A ₂ (V _io -V ₂ )...(2) Here, the overall output voltage V _put via the diodes 29 and 30 is equal to the lower of the output voltages V _10ut and V _20ut , so , A ₁ <A ₂ and A ₁ V ₁ <
If you set A ₂ V ₂ , as shown in Figure 2,
When the input voltage V _io becomes equal to the predetermined value V ₀ , a polygonal line characteristic with a variation point can be obtained, and the gains A ₁ , A ₂ and the reference voltage are adjusted to have the polygonal line characteristic.
V ₁ and V ₂ are set.

The deviation calculation circuit 11 similar to the conventional example has a third operational amplifier 33, and the inverting input terminal of this operational amplifier 32 is connected to the thermal load calculation circuit 10 via the resistor 34 as described above. The inverting input terminal is connected to the movable element of the potentiometer 9 through a resistor 35, and the output voltage from the potentiometer 9 is controlled by the third operational amplifier 33.
A deviation between V _p and the output voltage V _put of the thermal load calculation circuit 10 is calculated. It is amplified and a voltage V _a is output.
Further, series resistors 36 to 39 for generating reference voltages V ₃ and V ₄ (V ₃ > V ₄ ) are connected between the power line l ₁ and the earth line l ₂ , and one of the reference voltages V ₃ is The other reference voltage V ₄ is applied to the non-inverting input terminal of the fourth operational amplifier 40 and to the inverting input terminal of the fifth operational amplifier 41 via resistors 42 and 43, respectively. Further, the inverting input terminal of the fourth operational amplifier 40 and the non-inverting input terminal of the fifth operational amplifier 41 are connected to the output terminal of the third operational amplifier 33 via resistors 44 and 45. 5 operational amplifiers 40 and 41 are
Compare the input voltage V _a with the reference voltages V ₃ and V ₄ and find that V _a > V ₃
>V ₄ , “H”, “L”, V ₃ >V _a >V ₄ , “L”, “L”, V ₃ >V ₄ >V _a ,
Outputs “L” and “H” respectively. A feedback resistor 46 is inserted between the connection point with the resistors 37 and 38 and the non-inverting input terminal of the third operational amplifier 33 to form a Schmitt circuit.

The drive circuit 12 similar to the conventional example includes resistors 47 to 5.
0 and resistors 51 to 54, these series circuits are connected between the power supply line _l1 and the earth line _l2 , and the resistor 48
and the resistor 49 are connected to the fourth operational amplifier 4.
0 is connected to the output terminal, and a connection point between the resistors 53 and 54 is connected to the output terminal of the fifth operational amplifier 41, respectively. Further, this drive circuit 12 is
Two PNP type transistors 55, 56 and two
It has NPN type transistors 57 and 58. These transistors 55 to 58 are connected in a cross-connected manner, with the emitter of the transistor 55 connected to the power supply line _l1 , and its base connected to the resistors 47 and 48.
, its collector is connected to the collector of the transistor 57, its base is connected to the connection point of the resistors 49 and 50, its collector is connected to the earth line _l2 , the emitter of the transistor 56 is connected to the power supply line _l1 , and its base The collector of the resistors 51 and 52 is connected to the collector of the transistor 58, the base of the transistor 58 is connected to the junction of the resistors 53 and 54, and the collector is connected to the ground line _l2 . One terminal of the motor 8 is connected to the connection point between the transistor 55 and the transistor 57, and the other terminal is connected to the connection point between the transistor 56 and the transistor 58.
are connected to the respective connection points. Therefore, when the outputs of the fourth and fifth operational amplifiers 40 and 41 are "H" and "L", the transistor 5
5 and 58 are turned off, transistors 56 and 57 are turned on, the motor 8 is energized via the transistors 56 and 57, and the motor 8 rotates in the normal direction to increase the opening degree Θ of the air mix door 3 (heat side). In the case of "L" and "H", the transistor 56 and transistor 57 are turned off, and the transistor 55 and transistor 58 are turned on,
The motor 8 is energized via the transistors 55 and 58, and the motor 8 is reversed to open the air mix door 3.
Move the opening Θ in the direction of decreasing (cool side),
In the case of "L", "L", transistors 55, 56
is turned on, but transistors 57 and 58 are turned off, the motor 8 is not energized, and the air mix door 3 is stopped.

In the above configuration, if the temperature inside the vehicle is considerably higher than the set temperature of the temperature setting device 13, for example,
Since the resistance value of the vehicle interior sensor 14 becomes small, the input voltage V _io also becomes small, and the output voltage V _put of the thermal load calculation circuit 12 becomes considerably high according to the characteristics shown in FIG. 2. At this time, if the air mix door 3 is opened to the heat side, the output voltage V _p of the potentiometer 9 will be considerably lower than the output voltage V _put .
The output voltage V _a becomes V ₃ > V ₄ > V _a . Therefore, the output of the fourth operational amplifier 40 becomes "L" and the output of the fifth operational amplifier 41 becomes "H", so the transistors 56 and 57 of the drive circuit 12 are turned off and the transistors 55 and 58 are turned on, and the motor is turned off. 8 is reversed and moves the air mix door 3 to the cool side.
As a result, the output voltage V _p of the potentiometer 9
increases, and the output voltage of the thermal load calculation circuit 10 increases.
V _put , the output voltage of the third operational amplifier 33
V _a becomes V ₃ > V _a > V ₄ . Therefore, the outputs of the fourth and fifth operational amplifiers 40 become "L", so the transistors 57 and 58 of the drive circuit 12 are turned off, stopping the drive of the motor 8, and the air mix door 3 is shifted to the cool side. Stop at the ivy position.

In this way, when the air mix door 3 moves to the cool side, the amount of air passing through the heater core 2 decreases, so the temperature of the blown air decreases, and the temperature inside the vehicle gradually decreases. Therefore, the resistance value of the vehicle interior temperature sensor 14 gradually increases, the input voltage V _io of the thermal load calculation circuit 10 also gradually increases, and its output voltage V _put gradually decreases according to the characteristics shown in FIG. death,
Finally, since V _put <V _p , the output voltage V _a of the third operational amplifier 33 becomes V _a > V ₃ > V ₄ .
Therefore, the output of the fourth operational amplifier 40 is "H",
Since the output of the fifth operational amplifier 41 becomes "L", the transistors 56 and 57 of the drive circuit 12 are turned on and the transistors 55 and 58 are turned off, and the motor 8 rotates normally to move the air mix door 3 to the heating side. As a result, the output voltage V _p of the potentiometer 9 decreases, and as in the case described above, the air mix door 3 stops when it is balanced with the heat load, and the opening degree Θ of the air mix door 3 is determined according to the heat load. This automatically controls the blowing air temperature t.

In this way, the opening degree Θ of the air mix door 3 is determined according to the heat load, but even though the temperature of the blown air changes rapidly around the opening degree Θ1 due to the characteristics of the heater unit, the opening degree Θ of the air mix door ₃ is determined according to the heat load. The output voltage V _p of the meter 9 is a signal when the opening degree Θ of the air mix door 3 changes linearly. However, the thermal load calculation circuit 10 has an input voltage V _io
Since the output voltage V _put characteristic is constructed of an absolute value circuit with a polygonal line as shown in Fig. 2, the change in heat load corresponds to the opening Θ of the air mix door 3 near the opening Θ ₁ . A correction calculation is made so that the value changes more rapidly than it actually does. Therefore, the change in the opening of the air mix door 3 near the opening Θ ₁ becomes gradual, so the blowing air temperature t follows the target characteristic shown in FIG. Also, the rate of change of the blowing air temperature t can be made substantially the same.

In the above embodiment, the output characteristic of the thermal load calculation circuit is a polygonal line with one variation point, but by adding an operational amplifier, for example, it can be made to have two or more variation points, thereby making it possible to further improve the blowing air temperature. It can also be brought close so that it changes linearly.

(Effects of the invention) As described above, according to this invention, the heat load calculation circuit in the control circuit is configured as an absolute value circuit whose output voltage characteristics with respect to the input voltage are shown by a polygonal line. It is possible to correct sudden changes in the rate of change, linearly change the temperature of the blown air, and improve the feeling for the occupants. In addition, since the correction is performed in the control circuit, a commonly used so-called B-characteristic potentiometer can be used as is, and by changing the resistance value etc. in the control circuit, it is compatible with various automotive air conditioners. can,
This makes it possible to provide an inexpensive and versatile temperature control device.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of this invention, Fig. 2 is a characteristic diagram showing the output voltage characteristics of the thermal load calculation circuit used in the above, Fig. 3 is a configuration diagram showing a conventional example, and Fig. 4 The figure is a characteristic diagram showing the temperature characteristics of the blown air in the related art. 3... Air mix door, 5... Actuator, 7... Control circuit, 9... Potentiometer,
10... Heat load calculation circuit, 11... Deviation calculation circuit, 12... Drive circuit, 17... Air conditioning information source.

Claims (1)

[Scope of Utility Model Registration Claim] A potentiometer that detects the opening degree of the air mix door, an air conditioning information source that outputs a signal regarding the air conditioning status in the vehicle interior, and a heat load in the vehicle interior based on the output of this air conditioning information source. A thermal load calculation circuit that calculates, a deviation calculation circuit that calculates the deviation between the calculated value of this thermal load calculation circuit and the output from the potentiometer, and a drive circuit that outputs a drive signal in accordance with the output of this deviation calculation circuit. and an actuator that moves the air mix door in accordance with an output of the control circuit, the temperature control device for an automotive air conditioner comprising: 1. A temperature control device for an air conditioner for an automobile, characterized in that it is configured with an absolute value circuit having a polygonal characteristic.