JP3398512B2 - Air mix control device for automotive air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-mix control device for a vehicle air conditioner. 2. Description of the Related Art As a conventional air mix control in an air conditioner for automobiles, an air mix door is driven by a motor in order to accurately obtain a desired air mix door opening without generating hunting. There is an air mix door actuator which performs duty control. FIG. 4 is a flowchart showing a processing procedure of a conventional air mix control by such a duty control. Note that, here, only a brief description will be given in order to explain in detail later. First, various data values (for example,
The set temperature, the vehicle interior temperature, the outside air temperature, the amount of solar radiation, the current air mix door opening, etc.) are input (step S1),
The target room temperature and the S value (outflow air temperature deviation) are sequentially calculated by a predetermined arithmetic expression (step S2, step S3). Then, the set temperature is checked (step S
4) If the temperature is 18 ° C., the air mix door actuator is driven to the cool side at a duty ratio of 100% in order to set the air mix door to the full cool position (step S7). Drives the air mix door actuator to the hot side at a duty ratio of 100% to set the air mix door to the full hot position (step S11). As a result of the comparison in step S4, the set temperature is between 18 ° C. and 32 ° C. (for example, from 18.5 ° C. to 3 ° C.).
(1.5 ° C.), the S value is compared with ± 5 ° C. (step S5). If it is less than −5 ° C., the target temperature is lower and the deviation is larger, so the process proceeds to step S7. S
When the value is larger than 5 ° C., the process proceeds to step S11 because the target temperature is higher and the deviation is larger. If the result of the comparison in step S5 indicates that the S value is between -5 ° C. and 5 ° C., the S value is further compared with ± 2 ° C. (step S6). By this comparison, the S value is -2.
If the temperature is lower than ℃, the air mix door actuator is driven to the cool side at a duty ratio of 80% (step S
8) If the S value is larger than 2 ° C., the air mix door actuator is driven to the hot side at a duty ratio of 80% (step S10). If the S value is −2 ° C. or more and 2 ° C. or less, the air mix door actuator is driven. The door actuator is held (step S9). As described above, in step S8 and step S10, the duty control with the duty ratio of 80% is performed. As a result, the air mix door actuator is driven slowly, and the occurrence of hunting is prevented. When the processing of steps S7 to S11 is completed, the routine returns, and a series of processing from step S1 is repeatedly executed in a short predetermined control cycle. However, in such conventional air mix control, a full cool position (air mix door opening is 0%) where the air mix door is a limit position or a full hot position is set. Even if it is already fixed at the position (air mix door opening 100%), S
When the value is greater than −5 ° C. and less than −2 ° C., or when the value is greater than 2 ° C. and less than 5 ° C., a drive signal having a duty ratio of 80% is output to the air-mix door actuator (step S8, step S10). Duty ratio 8
In order to generate a 0% signal, it is necessary to repeatedly turn on and off a transistor and the like, so that noise is likely to occur.
Therefore, if a signal having a duty ratio of 80% is continuously output in the above-described case, noise may be input to a radio or the like. The present invention has been made in view of the above-mentioned problems of the prior art, and is an automobile capable of effectively preventing a noise disturbance that may be caused by duty control without increasing the cost. It is an object of the present invention to provide an air mix control device of an air conditioner for a vehicle. In order to achieve the above object, according to the first aspect of the present invention, there is provided an air mix door for adjusting the temperature of blown air, and the air mix door is driven by a motor. An air-mix door actuator, and control means for duty-controlling the air-mix door actuator based on control parameter values obtained by arithmetically processing various input signals, and always setting the air-mix door to an optimal opening. An air mix control device for an automotive air conditioner, comprising: a door opening detection unit that detects an opening of the air mix door, wherein the control unit moves the air mix door actuator to a limit position of the air mix door. When the air mix door is opened, the current air mix door opening detected by the door opening detecting means is moved forward. It is characterized in that the duty control is released when the vehicle reaches a predetermined area with the limit position as one end. According to the first aspect of the present invention, the door opening detecting means detects the current opening of the air mixing door, and the control means controls the air mixing door actuator. When the air mixing door is driven toward the limit position (full cool position or full hot position), the current air mix door opening detected by the door opening detecting means is preset with the limit position as one end. When reaching the area, the duty control (control by a drive signal having a duty ratio of less than 100%) is released. Thus, when the air mix door has reached the limit position, the duty control is not always performed regardless of the value of the control parameter, so that the duty ratio is 100%.
It does not happen that the drive signal of less than continues to be output. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air mix control device of an automotive air conditioner according to one embodiment of the present invention. In FIG. 1, a heater unit 2 for heating air using hot water (for example, engine cooling water) is provided in a heater unit 1 constituting a vehicle air conditioner main body. An air mix door 3 for adjusting the blown air temperature is rotatably mounted. The ratio of the air passing through the heater core 2 and the air bypassing the heater core 2 is adjusted by the air mixing door 3. That is,
The ratio of the amount of cold air cooled by an evaporator (not shown) provided upstream of the heater core 2 to be heated and heated by passing through the heater core 2 and the amount of cold air after passing through the evaporator bypassing the heater core 2 is adjusted. . In this manner, the temperature of the air blown into the vehicle compartment (the temperature of the blown air) is determined by the mixing ratio of the cool air and the hot air determined by the opening of the air mix door 3. The air mix door 3 is located at position A (full cool position) and position B (full hot position) in the figure.
And freely rotate between them as a limit position. When the air mix door 3 is at the position A (full cool position),
The opening degree is 0%, and all the cool air after passing through the evaporator bypasses the heater core 2 and is blown directly into the vehicle compartment.
Maximum cooling is demonstrated. Air mix door 3 is B
When in the position (full hot position), the opening is 100
%, And all the cool air after passing through the evaporator passes through the heater core 2 and is heated and blown out as warm air into the vehicle compartment, thereby exhibiting maximum heating. The air mix door 3 is driven by an air mix door actuator 4. The air mix door actuator 4 is a motor actuator including a motor 5, and opens and closes the air mix door 3 via a link mechanism (not shown) connected to a shaft.
Further, the air mix door actuator 4 has a built-in PBR (potentiometer balance register) 6 which is a variable resistor that moves in conjunction with the shaft. A signal of the position (opening) of the air mix door 3 is output. FIG. 2 is a characteristic diagram of PBR6. As shown in the figure, the opening of the air mix door 3 can be uniquely known from the resistance value of the PBR 6. As will be described later, supply of drive power to the motor 5 in the air mix door actuator 4 is performed by the auto amplifier. The air mix door actuator 4 is connected to an auto amplifier 7 and is controlled by this. The auto amplifier 7 has a microcomputer 8 and a motor driver 9 built therein. Further, the auto amplifier 7 has an air conditioner switch 10 for turning on a compressor (not shown) to operate the air conditioner, a temperature control switch 11 for adjusting the temperature in the vehicle interior, and detects the temperature (room temperature) of the vehicle interior air. Inside air sensor 12, outside air sensor 1 for detecting outside air temperature
3. The solar radiation sensor 14 for detecting the amount of solar radiation, other appropriate switches (not shown) and the respective sensors are connected. As described above, the PBR 6 in the air mix door actuator 4 for detecting the opening of the air mix door 3 is also connected to the auto amplifier 7. The microcomputer 8 in the auto amplifier 7 processes input signals from the switches 10 and 11, the sensors 12, 13 and 14, and the PBR 6 to generate a control signal for operating the air mix door actuator 4. To the motor driver 9. The motor driver 9 supplies a predetermined drive power to the motor 5 in the air mix door actuator 4 according to a control signal from the microcomputer 8. At that time, as described later, in controlling the air mix door actuator 4 by the auto amplifier 7, the duty control is performed in order to increase the accuracy of the opening degree of the air mix door 3, that is, the accuracy of the air mix (temperature control). Do. Although not shown, the air mix door actuator 4 has a built-in pattern switch, and when the air mix door 3 reaches a limit position, a full cool position (A position) and a full hot position (B position), respectively. The output from the motor driver 9 does not reach the motor 5 only in the direction toward FIG. 3 is a flowchart showing a processing procedure of the air mix control by the microcomputer 8. This processing procedure is an improvement of the conventional processing procedure shown in FIG. Specifically, the difference is that the determinations of step S26 and step S27 are newly added to the processing procedure shown in FIG. Hereinafter, the contents of each process will be described more specifically. First, each of the sensors 12 to
Signals from the PBR 14, the PBR 6, and the temperature control switch 11 are input, and the microcomputer 8 recognizes the current vehicle interior temperature, the outside air temperature, the amount of solar radiation, the air mix door opening, and the set temperature, respectively (step S20). Then, the microcomputer 8 calculates a target room temperature by a predetermined arithmetic expression (step S21). Here, depending on the case, various corrections, for example, corrections that take into account the characteristics of the vehicle itself, corrections that take into account the link characteristics for the air mix door opening based on the PBR value, corrections that take into account the temperature control characteristics in the outlet mode, and the like. Done. Then, a predetermined arithmetic expression (vehicle thermal equilibrium expression)
Thus, the blowout temperature deviation (= target temperature−current temperature) (referred to as S value) as a control parameter is calculated (step S22). This S value also includes various correction values as the case may be. As will be described later, control of the blowing air temperature,
That is, control of the air mix door opening is performed by deviation control based on the S value. Then, the microcomputer 8 checks the current set temperature inputted in step S1 (step S23),
When the temperature is, for example, 18 ° C., the air mix door actuator 4 is moved to the cool side (that is, in the direction toward the A position) at a duty ratio of 100% in order to set the air mix door 3 to the full cool position (A position). When the set temperature is, for example, 32 ° C., the air mix door actuator 4 is moved to the hot side (that is, the air mix door actuator 4 is set to the full hot position (B position)).
Control signals for driving at a duty ratio of 100% (in the direction toward the position B) are generated and sent to the motor driver 9 (steps S28 and S32). This allows
The air mix door actuator 4 is a motor driver 9
And the air mix door 3 is quickly driven to the cool side or the hot side, respectively, and the air mix door 3 is fixed at the full cool position (A position) or the full hot position (B position), respectively. Will be. Here, the duty ratio of 100% is 1 of the pulse signal.
The ratio of the ON time to the cycle is 100%, which means that only the ON signal is output. In this embodiment, the air mix door 3 is set to the full cool position and the full hot position when the set temperatures are 18 ° C. and 32 ° C., respectively. Is not limited to the above value. As a result of the determination in step S23, the set temperature is between 18 ° C. and 32 ° C. (for example, from 18.5 ° C. to 3 ° C.).
If 1.5 ° C.), the S value obtained in step S22 is compared with, for example, ± 5 ° C. (step S24). If the S value is less than -5 ° C. as a result of this comparison, the target temperature is lower and the deviation is larger. Therefore, the process proceeds to step S28 in order to eliminate the deviation as soon as possible, and when the S value is larger than 5 ° C. Since the target temperature is higher and the deviation is larger, the process proceeds to step S32 in order to eliminate the deviation earlier. As a result, the air mix door actuator 4 receives the power supply from the motor driver 9 at a duty ratio of 100% and is quickly driven to the cool side or the hot side, respectively, so that the air mix doors 3 move toward the optimum opening. And approach quickly. If the result of the comparison in step S24 indicates that the S value is not lower than -5.degree.
Compare with 2 ° C. (step S25). As a result of this comparison, when the S value is not less than −2 ° C. and not more than 2 ° C., it is determined that the air mix door 3 is within the target temperature control control range, and the air mix door actuator 4 is held. A control signal is generated and output to the motor driver 9 (step S30). Thus, the air mix door actuator 4 is held at that position, and the air mix door 3 is held at that opening. Note that ± 2 ° C. compared in step S25
The range of “within” is a temperature control control range desired to be achieved as a target, and is of course not limited to that value. In general, the accuracy of the temperature control is improved as the range is narrower.On the other hand, hunting is more likely to occur as the control range is narrowed. Good. In the present embodiment, since the target temperature control control range is set to a narrow range of ± 2 ° C. or less, as described later, the S value (deviation) is set to −5 ° C. in order to suppress the occurrence of hunting. Is larger than −2 ° C. or larger than 2 ° C. and less than 5 ° C., the duty ratio 8
The air mix door actuator 4 is slowly driven by performing 0% duty control, and the air mix door 3 is controlled.
Is slowly brought close to the target temperature control range (the deviation is within ± 2 ° C.). When the S value is less than −2 ° C. as a result of the comparison in step S25, that is, when the S value is greater than −5 ° C. and less than −2 ° C., the current air mix detected by the PBR 6 is further reduced. Based on the door opening, it is determined whether or not the air mix door 3 is within a predetermined duty control prohibition region C set in advance (step S26). Duty control prohibited area C here
Is duty control (that is, duty control) to prevent the motor driver 9 from continuing to output drive power with a duty ratio of 80% even though the air mix door 3 has reached the full cool position (A position). 80% of the ratio
In this embodiment, the opening of the air mix door is set in a range of 5% from the full cool position (opening 0%) (FIG. 2).
reference). However, the duty control prohibition area C is for checking whether or not the air mix door 3 has reached the full cool position (A position). Therefore, only when the air mix door actuator 4 is driven to the cool side. Applied. In the present embodiment, the width of the duty control prohibition region C is set to 5%. However, this is because the detection error of the PBR 6 is taken into consideration, and is of course not limited to this value. If the detection error of the PBR 6 is small, it is possible to make the width of the duty control prohibition region C narrower. Conversely, if the detection error is large, the width of the duty control prohibition region C needs to be widened . If the result of the determination in step S26 is that the air mix door 3 is in the duty control prohibition area C while moving to the cool side, the air mix door 3 reaches the full cool position (position A). In step S28, the duty output from the motor driver 9 is switched from 80% to 100%. That is, the duty control of the duty ratio of 80%, at which noise easily occurs, is canceled, and the duty ratio of 100, at which noise does not easily appear, is released.
Switch to% ON control. The air mix door 3
Has reached the limit position (full cool position), the power supply from the motor driver 9 (only when driven to the cool side) is cut off by the pattern switch as described above. On the other hand, if the result of determination in step S26 is that the air mix door 3 is not in the duty control prohibition area C while moving to the cool side,
Judging that the air mix door 3 has not reached the full cool position (A position), in order to prevent hunting,
A control signal for driving the air mix door actuator 4 to the cool side at a duty ratio of 80% is generated and output to the motor driver 9 (step S29). This allows
The air mix door actuator 4 is a motor driver 9
The air mix door 3 is driven to the cool side more slowly than the case of the duty ratio of 100% by receiving the power supply with the duty ratio of 80% from the air conditioner, and the air mixing door 3 is brought into the target temperature control control range (the deviation is within ± 2 ° C.). You will approach slowly.
In this embodiment, the duty ratio in this case is set to 80%
, But it is a matter of course that the present invention is not limited to this value. Considering the width of the target temperature control range, etc., the air mix door 3 that does not cause hunting
It may be set to an appropriate value so that the moving speed is obtained. On the other hand, if the S value is greater than 2 ° C. as a result of the comparison in step S25, that is, if the S value is greater than 2 ° C. and less than 5 ° C., the detection is performed by the PBR 6 in the same manner as in step S26. It is determined whether or not the air mix door 3 is within a predetermined duty control prohibition region D set in advance based on the current air mix door opening (step S27). The duty control prohibition region D here is for preventing the motor driver 9 from continuing to output driving power with a duty ratio of 80% even when the air mix door 3 has reached the full hot position (B position). Duty control (that is, control using an output signal with a duty ratio of 80%)
In this embodiment, as in step S26, the air mix door opening is set to a width of 5% from the full hot position (opening 100%). That is, the air mix door opening is 95% to 100%.
The range of% (full hot position) is the duty control prohibition region D (see FIG. 2). However, the duty control prohibition region D is also used to check whether the air mix door 3 has reached the full hot position (B position). Therefore, when the air mix door actuator 4 is driven to the hot side. Only applies. Note that the duty control prohibited area D is not limited to the width of 5% as in the case of the duty control prohibited area C described above. If the result of the determination in step S27 is that the air mix door 3 is in the duty control prohibition area D while moving to the hot side, the air mix door 3 reaches the full hot position (position B). In step S32, the duty output from the motor driver 9 is switched from 80% to 100%. That is, the duty control of the duty ratio of 80%, at which noise easily occurs, is canceled, and the duty ratio of 100, at which noise does not easily appear, is released.
Switch to% ON control. The air mix door 3
Has reached the limit position (full hot position), the power supply from the motor driver 9 (only when driven to the hot side) is cut off by the pattern switch as described above. On the other hand, if the result of determination in step S27 is that the air mix door 3 is not in the duty control prohibition area D while moving to the hot side,
It is determined that the air mix door 3 has not reached the full hot position (position B), and a control signal for driving the air mix door actuator 4 to the hot side at a duty ratio of 80% is generated and output to the motor driver 9. (Step S31). As a result, the duty ratio of the air mix door actuator 4 from the motor driver 9 is 80%.
100% duty ratio to hot side by receiving power supply at
Driven more slowly than in the case of
Will slowly approach the target temperature control range (with a deviation within ± 2 ° C.). Steps S28 to S32 described above
When the process is completed, the process returns, and a series of processes from step S20 is repeatedly executed in a short predetermined control cycle.
As a result, the air mix door 3 is always set to the optimum opening, and the target temperature control is obtained. Therefore, according to the present embodiment, when the air mix door 3 reaches the duty control prohibition region C or D, that is, it reaches the full cool position (A position) or the full hot position (B position). Is determined, the S value (deviation) is in the control range (−−) where the duty ratio is 80%.
(When the temperature is greater than 5 ° C. and less than −2 ° C. or when the temperature is greater than 2 ° C. and less than 5 ° C.), the duty control of the duty ratio of 80% is forcibly released to reduce the duty ratio of 100%. Since the control is switched to the ON control, an output with a duty ratio of 80%, at which noise easily occurs, is output even when the air mix door 3 has reached the full cool position (A position) or the full hot position (B position). Will not be continued, and the duty ratio will be 80%
Can be effectively prevented from occurring due to the duty control. In order to obtain the above-mentioned effects, it is not necessary to add any components, and it is possible to cope only with a change (addition) of the program stored in the microcomputer 8.
There is no cost increase. As described above, according to the first aspect of the present invention, when the air mix door has reached the limit position, duty control (duty ratio) is always performed regardless of the value of the control parameter. Since the control by the drive signal of less than 100% is canceled, the drive signal of the duty ratio of less than 100% does not continue to be output, and the change of the program alone may occur due to the duty control of the duty ratio of 80%. Noise interference can be effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an air mix control device of an automotive air conditioner according to an embodiment of the present invention. FIG. 2 is a PBR characteristic diagram. FIG. Flowchart showing a processing procedure [FIG. 4] Flowchart showing a processing procedure of a conventional air mix control [Description of symbols] 3 ... Air mix door 4 ... Air mix door actuator 5 ... Motor 6 ... PBR 7 ... Auto amplifier (control means) 8 Microcomputer 9 Motor driver

Claims (1)

(1) An air mix door (3) for adjusting the temperature of blown air, and an air mix door actuator (3) for driving the air mix door (3) by a motor (5). 4) and control means (7) for duty-controlling the air-mix door actuator (4) based on control parameter values obtained by performing arithmetic processing on various input signals. An air mix control device for an automotive air conditioner, which always sets an optimum opening degree, comprising: a door opening degree detecting means (6) for detecting an opening degree of the air mixing door (3); When the air-mix door actuator (4) is driven toward the limit position of the air-mix door (3), the current detected by the door opening detection means (6) is An air mix control device for an automotive air conditioner, wherein the duty control is canceled when the air mix door opening reaches a predetermined region with the limit position as one end.