JP3925028B2 - Automotive air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an automobile air conditioner, and more particularly to an improvement for protecting a blower fan motor drive circuit and continuing the operation of the air conditioner.
[0002]
[Prior art]
An automotive air conditioner in which an inside / outside air switching damper, a blower fan, an evaporator, and the like are provided in a duct serving as an air passage, and a swing position of the inside / outside air switching damper is adjusted by a damper position command means provided in a control unit. It is already known.
[0003]
Usually, in this type of automotive air conditioner, in addition to the above-described components, sensors such as an internal air temperature sensor, an external air temperature sensor, an engine water temperature sensor, an evaporator temperature sensor, and a heater core are provided. On the basis of the various temperature data detected in step 1, the required blow temperature calculating means provided in the control unit of the air conditioner calculates the required blow temperature according to a predetermined calculation program.
[0004]
The required blowing temperature here is, in short, the temperature of air to be sent from the air conditioner in order to achieve the set indoor temperature target value. Finally, considering the relationship between the inside air temperature, the outside air temperature, and the necessary air temperature, etc., the damper position command means automatically calculates the swing position of the inside / outside air switching damper suitable for obtaining the desired air temperature required. The damper position control means automatically controls the swing position of the inside / outside air switching damper.
[0005]
Many of these damper position command means can be manually adjusted even for automatic air conditioners. In the manual mode, in addition to the automatic operation mode described above, internal and external operations are performed based on the driver's manual operation. By adjusting the position of the air switching damper, it is possible to freely select the intake of outside air or the intake of inside air.
[0006]
On the other hand, in this type of automobile air conditioner, it is assumed that a considerable load is also applied to the motor that drives the blower fan, and there is a concern about heating or overloading of the motor drive circuit composed of a power transistor or the like. The
[0007]
[Problems to be solved by the invention]
Conventionally, as a means for solving this type of problem, a motor drive circuit equipped with a heat sink or the like is installed in a duct of an air conditioner, and this is forcibly cooled by air from a blower fan. It has been.
[0008]
However, when the inside air circulation is selected and the temperature in the duct itself is rising, there is a limit to the effect of forced air cooling by the blower fan and evaporator, and the motor drive circuit is insufficiently cooled. In such a case, there is no method other than to stop the rotation of the blower fan and protect the motor drive circuit.
[0009]
For example, this phenomenon may occur when a passenger gets in a state where the vehicle is left under the hot summer heat, and manually operates the inside / outside air switching damper in manual mode to select the inside air circulation and starts cooling, or This occurs when the internal air circulation is continuously selected in the automatic operation mode under similar conditions.
[0010]
When the rotation of the blower fan is stopped in this way, the forced air cooling effect on the motor drive circuit is also lost, so the cooling of the motor drive circuit is left to natural heat dissipation, and this motor drive circuit is suitable for operation. There is a problem that the time until the temperature returns is prolonged.
[0011]
And until the motor drive circuit returns to an appropriate temperature, the blowing by the blower fan stops and the air conditioner becomes substantially inactive, so that the passenger can obtain the desired air conditioning effect during this period. It is impossible to do so, and the user is forced to feel uncomfortable.
[0012]
In addition, when a configuration including such an emergency stop function is applied, it is necessary to detect the temperature rise of the motor drive circuit and stop the blower fan drive, and a dedicated temperature detection sensor must be provided in the motor drive circuit. However, there is a problem from the viewpoint of the manufacturing cost of the device.
[0013]
OBJECT OF THE INVENTION
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automotive air conditioner that eliminates the drawbacks of the prior art and that can protect a blower fan motor drive circuit without requiring a special temperature detection sensor and without stopping the apparatus. It is to provide.
[0014]
[Means for Solving the Problems]
The present invention has an inside / outside air switching damper, a blower fan, and an evaporator in a duct serving as an air passage, and includes a damper position command means for commanding a swing position of the inside / outside air switching damper to a control unit thereof. In order to achieve the above object, an automotive air conditioner is provided with a motor drive circuit and an evaporator temperature sensor for a motor that drives a blower fan, particularly at a downstream position close to the evaporator, and the controller The comparison means for comparing the magnitude relationship between the duct internal temperature detected by the evaporator temperature sensor and the preset judgment value, and the internal and external values according to the command from the damper position command means when the duct internal temperature does not reach the judgment value. While the air switching damper is held at the command position, if the duct temperature exceeds the judgment value, The air changeover damper forcibly provided with limiting function with damper position control means for switching to the external air intake port side, The control unit is provided with damper position display means for displaying the damper position commanded by the damper position command means regardless of the actual swing position of the inside / outside air switching damper. It has the structure characterized by this.
[0015]
According to this configuration, when the temperature in the duct does not reach the determination value, that is, when the temperature of the air blown from the blower fan to the motor drive circuit is in a state suitable for forced air cooling, the command by the damper position command means The inside / outside air switching damper is held at the position, that is, the damper position calculated by the damper position command means in the automatic operation mode or the damper position designated by the driver via the damper position command means in the manual mode.
Also, when the temperature inside the duct exceeds the judgment value, that is, when the cooling is started with the inside air circulation selected under the hot sun, the temperature of the air blown from the blower fan to the motor drive circuit is forced to air cooling. When it rises to an unsuitable state, the command position by the damper position command means is ignored and the inside / outside air switching damper is forcibly switched to the outside air intake side by the damper position control means with limiting function.
As a result, instead of the hot air inside the vehicle heated under the sun, fresh external air is sent to the motor drive circuit, and the forced air cooling effect by the blower fan is increased. Therefore, the air conditioning process can be continuously performed without stopping the blower fan to protect the motor drive circuit, and the interior of the vehicle can be cooled within a short time.
In addition, since an evaporator temperature sensor is used as a means for detecting the temperature of the air blown to the motor drive circuit, it is not necessary to provide a special temperature detection sensor in the motor drive circuit itself, and the manufacturing cost of the device Is reduced.
Moreover, the damper position display means displays as if the inside / outside air switching damper is held at the command position intended by the driver regardless of the actual swinging position of the inside / outside air switching damper. Become. Therefore, even when the inside / outside air switching damper is forcibly switched to the outside air intake side by the damper position control means with the limiting function, the driver knows the fact and does not feel uncomfortable, Can concentrate on driving .
[0016]
Further, the comparison means includes a first judgment value applied when forcibly switching the inside / outside air switching damper from the command position by the damper position command means to the outside air intake side, and a command by the damper position command means from the outside air intake side. A storage unit storing a second determination value applied when switching the inside / outside air switching damper to a position, and a second determination value as the determination value when the duct internal temperature exceeds the first determination value On the other hand, it is possible to provide a hysteresis setting function for selecting the first determination value as the determination value when the duct internal temperature falls below the second determination value.
[0017]
According to this configuration, since the temperature interval between the first determination value and the second determination value acts as a dead zone related to the switching control of the inside / outside air switching damper, the variation in the detected temperature of the evaporator temperature sensor Thus, the inadvertent swinging operation of the inside / outside air switching damper is prevented, and smooth air conditioning control is achieved. It is also effective in improving the durability of the device.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram schematically showing a main part of an automotive air conditioner according to an embodiment to which the present invention is applied.
[0021]
The mechanism part of this automotive air conditioner 1 includes an inside / outside air switching damper 3, a blower fan 4 and an evaporator 5, and a heater core 6, an air mix damper 7 and a mode damper 8a. , 8b, 8c.
[0022]
The evaporator 5 constituting the cooler is a part of a refrigerant circulation system configured by adding a compressor 19, a condenser 20, a liquid tank 21, and an expansion valve 22, and is driven by the power of the engine 24 when the electromagnetic clutch 23 is energized. The refrigerant is cooled by the cooling and liquefying action and the expansion action of the gaseous refrigerant sent from the compressor 19.
[0023]
An upstream air intake 9 for taking in air from outside and an internal air intake 10 for taking in circulating air in the vehicle are provided upstream of the duct 2 serving as an air passage. Depending on the swing angle of the inside / outside air switching damper 3, outside air, inside air, or a mixture thereof is introduced into the duct 2.
[0024]
The air taken into the duct 2 in this way is sent to the downstream side by the air blowing means constituted by the motor 12 and the blower fan 4, and further cooled through the position where the evaporator 5 serving as a cooler is provided. The air mix damper 7 swung by the actuator 13 is divided into the heater core 6 side and the bypass side to adjust the amount of heat, and finally the air destination is regulated by the mode dampers 8a, 8b, 8c, It is sent into the vehicle from the defrost outlet 14, the vent outlet 15, or the heat outlet 16 constituting the air outlet.
[0025]
Further, an evaporator temperature sensor 30 for detecting the temperature of the air cooled after passing through the evaporator 5 and a motor drive circuit 34 for driving the motor 12 of the blower fan 4 are located at a downstream position close to the evaporator 5. The motor drive circuit 34 is forcibly air-cooled by the air blown from the blower fan 4 and cooled by the evaporator 5. The motor drive circuit 34 has a heat sink.
[0026]
The mode dampers 8a, 8b, and 8c are driven by an actuator 18 via a link mechanism 17 that links the swinging operations of the mode dampers 8a, 8b, and 8c.
[0027]
The swing positions of the mode dampers 8a, 8b, 8c are required based on the target temperature set by the temperature setting switch that constitutes the target temperature setting means and the detected values of the internal air temperature sensor 25 and the external air temperature sensor 26, etc. It is automatically calculated by the temperature calculation means. For example, when the necessary blow temperature is high, the air is blown to the heat blow outlet 16 which is one air blow outlet, and when the necessary blow temperature is low, the vent blow which is the other air blow outlet is provided. The mode dampers 8a, 8b, 8a, 8b, 8a, 8b 8c is moved.
[0028]
The swinging position of the inside / outside air switching damper 3 includes the inside air temperature detected by the inside air temperature sensor 25, the outside air temperature detected by the outside air temperature sensor 26, and the necessary blowing temperature calculated by the necessary blowing temperature calculating means. Based on the value and the like, it is automatically calculated by the damper position command means.
[0029]
The control unit 27 constituting the control unit of the automotive air conditioner 1 includes a CPU, a ROM, a non-volatile memory, and the like, and swings the motor drive circuit 34 of the motor 12 that rotationally drives the blower fan 4 and the inside / outside air switching damper 3. The actuator 11 that moves, the actuator 13 that swings the air mix damper 7, and the actuator 18 that swings the mode dampers 8 a, 8 b, and 8 c via the link mechanism 17 are driven and controlled by the CPU of the control unit 27. .
[0030]
Further, the actuator 13 for swinging the air mix damper 7 and the actuator 18 for swinging the mode damper dampers 8a, 8b, and 8c of the air outlets have rotational positions of the respective actuators, that is, air mix dampers. 7 and an air mix damper position detection sensor 28 and a mode damper position detection sensor 29 for detecting the rotation positions of the mode damper dampers 8a, 8b and 8c are provided. The air mix damper 7 and the mode damper dampers 8a and 8b are provided. , 8c are detected by the CPU. Further, the CPU detects the current temperature of the blown air detected by the evaporator temperature sensor 30 constituted by a thermistor or the like.
[0031]
Further, a signal from the air control panel 31 provided with a temperature setting switch constituting the target temperature setting means, a switch for manual operation of the inside / outside air switching damper 3, and the like, an inside air temperature sensor 25, an outside air temperature sensor 26, solar radiation Signals from the sensor 32 and the engine water temperature sensor 33 are also input to the CPU.
[0032]
In addition, the CPU of the control unit 27 controls the display state of the air control panel 31, the target value set by the temperature setting switch, the current value of the inside air temperature, the current value of the engine coolant, and the damper position command The swinging position of the inside / outside air switching damper 3 calculated by the means is displayed. That is, the air control panel 31 is a substantial damper position display means.
[0033]
FIG. 2 is a block diagram showing an outline of function realizing means constituted by a CPU, a non-volatile memory, etc. of the control unit 27 constituting the control unit of the automotive air conditioner 1. Among these, detection of the inside temperature and the outside temperature The function of the necessary blow temperature calculating means for calculating the required blow temperature based on the value, the target temperature, etc., and the function of the damper position command means for calculating the swing position of the inside / outside air switching damper 3 based on the calculation result, etc. Is already known.
[0034]
When the air conditioner is operating in the manual mode, the calculation processing related to the swing position of the inside / outside air switching damper 3 is not performed, and the swing position is determined by a switch operation from the air control panel 31. Directed to the means directly.
[0035]
On the other hand, the damper position control means with a limiting function is a component unique to the present embodiment, and also has a function as a conventional damper position control means.
[0036]
The storage unit for storing the determination value is constituted by a non-volatile memory in the control unit 27, and forcibly switching the inside / outside air switching damper 3 from the command position by the damper position command means to the outside air intake 9 side. The first determination value T1 (for example, 42 ° C.) applied at the time and the second determination value T2 (at the time of switching the inside / outside air switching damper 3 from the outside air intake 9 side to the command position by the damper position command means ( For example, 38 ° C.) is stored.
[0037]
Further, the comparison means constituted by the CPU selects the second determination value T2 as the determination value to be applied when the air temperature in the duct 2 exceeds the first determination value T1, while the duct 2 A hysteresis setting function for selecting the first determination value T1 as a determination value to be applied when the air blowing temperature falls below the second determination value T2 is also provided.
[0038]
Then, in a situation where one of the determination values T1 and T2 is selected as the determination value by the hysteresis setting function, the comparison means is selected at the present time with the blower temperature in the duct 2 detected by the evaporator temperature sensor 30. Compare the magnitude relationship with the judgment value.
[0039]
And when the ventilation temperature in the duct 2 has not reached the judgment value, the damper position control means with a limiting function holds the inside / outside air switching damper 3 at the command position in accordance with the command from the damper position command means (conventional function). In addition, when the air temperature in the duct 2 exceeds the determination value, the damper position control means with a limiting function forces the swing position of the inside / outside air switching damper 3 regardless of the command from the damper position command means. To the outside air intake 9 side (function unique to this embodiment).
[0040]
Next, with reference to the flowchart of the damper position control process shown in FIG. 3, the processing operations of the CPU as the damper position control means with limiting function and the comparison means will be described in detail. The damper position control process is a task process that is repeatedly executed by the CPU at a relatively short processing cycle of, for example, several hundred milliseconds.
[0041]
The CPU that has started the damper position control process first determines whether the mode of the air conditioner is the manual mode or the automatic operation mode (step a1), and if it is in the automatic operation mode. Then, the calculation process by the necessary blow temperature calculating means is executed to obtain the required blow temperature (step a2), and the calculation result is used to execute the automatic calculation process by the damper position command means in the same manner as in the past. The oscillation position of the inside / outside air switching damper 3 suitable for the above condition is obtained, and the value is temporarily stored in the execution value storage register θ (step a3).
[0042]
If the target value of the vehicle interior temperature set by the temperature setting switch is Tset, the current value of the indoor temperature detected by the internal air temperature sensor 25 is Tr, and the value of the external air temperature detected by the external air temperature sensor 26 is Tam, the required blowout The value of temperature Q is
Q = Kq ・ Wo (Kset ・ Tset-Kr ・ Tr-Kam ・ Tam + C-Tr)
Can be obtained. However, Kq, Wo, Kset, Kr, Kam, and C are constants determined by the physical properties of the air, the vehicle body structure, and the like.
[0043]
On the other hand, if the determination result of step a1 is false and it is determined that the mode of the air conditioner is in the manual mode, the step relating to the calculation of the required blowout temperature and the calculation of the swing position of the inside / outside air switching damper 3 The processing of a2 to step a3 is not executed, and the blowing temperature manually set through the air control panel 31 at that time is selected as the necessary blowing temperature, and the inside / outside air switching set manually at that time The swing position of the damper 3 is temporarily stored in the execution value storage register θ (step a4). This value is also temporarily stored in the display value storage register θd (step a5).
[0044]
Next, the CPU constituting the hysteresis setting function realizing unit determines whether or not the temperature zone storage flag F is set (step a6).
[0045]
The temperature zone storage flag F is set when the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 exceeds the first determination value T1, while the duct detected by the evaporator temperature detection sensor 30. This is a flag that is reset when the air temperature in 2 falls below the second determination value T2.
[0046]
Therefore, when the determination result in step a6 is true and it is clear that the temperature zone storage flag F is reset, the CPU as the comparison unit determines the first determination value to be used for the determination process. The value T1 is selected, and it is determined whether or not the current value Te of the blowing temperature in the duct 2 detected by the evaporator temperature detection sensor 30 exceeds the first determination value T1 (step a7).
[0047]
If the current value Te of the blowing temperature in the duct 2 does not exceed the first determination value T1, it means that the forced air cooling of the motor drive circuit 34 by the blower fan 4 is effectively performed. It is not necessary to apply a special operation to the swing position of the damper 3.
[0048]
Therefore, if the determination result in step a7 is false, the CPU determines whether the air conditioner mode is the manual mode or the automatic operation mode (step a10), and the air conditioner mode is When in the automatic operation mode, the swing position of the inside / outside air switching damper 3 stored in the execution value storage register θ is displayed on the air control panel 31 serving as a damper position display means (step a11). When the mode of the air conditioner is the manual mode, the swing position of the inside / outside air switching damper 3 stored in the display value storage register θd is displayed on the air control panel 31 (step a12).
[0049]
If the determination result in step a7 is false and it is clear that the forced air cooling of the motor drive circuit 34 by the blower fan 4 is being performed effectively, it is set by the processing in step a3 or step a4. Since no special operation is applied to the value of the execution value storage register θ, the value of the execution value storage register θ and the value of the display value storage register θd are the same.
[0050]
Next, the CPU as the damper position control means with a limiting function causes the inside / outside air switching damper 3 to move toward the value stored in the execution value storage register θ, that is, the swing position obtained in the process of step a3 or step a4. The actuator 11 is driven and controlled to move (step a13), and the damper position control process in this cycle is completed.
[0051]
After that, if the current value Te of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 does not exceed the first determination value T1, the damper position control process after the next cycle is performed in the same manner as described above in step a1. To step a7 (however, the processing of step a2 to step a3 and the processing of step a4 to step a5 are alternatives), and the processing of step a10 to step a13 (however, the processing of step a11 and step a12 The process is repeatedly executed as an alternative.
[0052]
On the other hand, while repeating such processing, the current value Te of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 exceeds the first determination value T1, and the determination result of step a7 becomes true. In this case, the forced air cooling of the motor drive circuit 34 by the blower fan 4 is insufficient. Therefore, regardless of whether the current operation mode is the manual mode or the automatic operation mode, the swing position of the inside / outside air switching damper 3 is forcibly switched to the outside air intake 9 side to stop the circulation of air in the vehicle. It is necessary to introduce fresh outside air and improve the forced air cooling effect of the motor drive circuit 34 by the blower fan 4.
[0053]
Therefore, when the determination result in step a7 becomes true, the CPU as the damper position control means with a limiting function sets the temperature zone storage flag F and detects the blowing temperature in the duct 2 detected by the evaporator temperature detection sensor 30. Has exceeded the first determination value T1 (step a8), the value currently stored in the execution value storage register θ, that is, the inside / outside air switching damper obtained in the processing of step a3 or step a4. 3 is ignored and the value for switching the inside / outside air switching damper 3 to the outside air intake 9 side is reset in the execution value storage register θ (step a9).
[0054]
In this embodiment, as shown in FIG. 1, the inside / outside air switching damper 3 is based on the swing position when the inside / outside air switching damper 3 closes the inside air intake 10 and completely opens the outside air intake 9. Therefore, in the processing of step a9, the minimum value of the swing angle that can be selected is set in the execution value storage register θ.
[0055]
FIG. 4 shows an example of switching timing from the swing control of the inside / outside air switching damper 3 according to the automatic calculation process of the damper position command means in step a3 or the manual setting operation in step a4 to the forced release control for taking in outside air. Shown at point X1. In order to simplify the explanation in FIG. 4, the command position of the inside / outside air switching damper 3 when following the automatic calculation process or manual setting operation of the damper position command means is shown by one straight line X0-X1. Actually, the command position (swinging angle) itself changes due to changes in various conditions used in the arithmetic processing and the manual operation of the driver.
[0056]
Next, the CPU determines whether the air conditioner mode is the manual mode or the automatic operation mode (step a10), and if the air conditioner mode is the automatic operation mode, the CPU executes The swing position of the inside / outside air switching damper 3 stored in the value storage register θ is displayed on the air control panel 31 serving as a damper position display means (step a11). Of course, what is displayed in this case is a minimum value of the swing angle, that is, a value indicating that the inside / outside air switching damper 3 has selected the outside air intake 9.
[0057]
If the determination result in step a10 is true and it is found that the air conditioner mode is the manual mode, the CPU swings the inside / outside air switching damper 3 stored in the display value storage register θd. The moving position, that is, the swing position of the inside / outside air switching damper 3 set in the process of step a4 is displayed on the air control panel 31 serving as a damper position display means (step a12). In this case, the swing position θd of the inside / outside air switching damper 3 displayed on the air control panel 31 is different from the actual swing position θ, but in the situation where the driver selects the manual mode, Displaying the set swinging position θd of the inside / outside air switching damper 3 does not cause a sense of incongruity.
[0058]
Next, the CPU as the damper position control means with a limiting function selects the value stored in the execution value storage register θ, that is, the swing position for selecting the outside air intake 9 forcibly set in the process of step a9. The actuator 11 is driven and controlled so that the inside / outside air switching damper 3 moves toward (step a13), and the damper position control process in this cycle is completed.
[0059]
Therefore, when the current value Te of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 exceeds the first determination value T1, the current operation mode is the manual mode or the automatic operation mode. Regardless of whether the swing position of the inside / outside air switching damper 3 is forcibly switched to the outside air intake 9 side, the air cooling effect of the motor drive circuit 34 by the blower fan 4 is improved.
[0060]
If the automatic operation mode is selected at this time, the actual swing position of the inside / outside air switching damper 3 is displayed on the air control panel 31 serving as the damper position display means, and the manual mode is selected. For example, the swing position of the inside / outside air switching damper 3 set by the driver manually is displayed regardless of the actual swing position of the inside / outside air switching damper 3.
[0061]
In this way, when the current value Te of the blast temperature in the duct exceeds the first determination value T1, the temperature zone storage flag F is set. Therefore, in the damper position control process of the next cycle, the determination result of step a6 Becomes false.
[0062]
Therefore, the CPU constituting the hysteresis setting function realizing unit selects the second determination value T2 as a determination value to be used for the determination process, and the current value of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30. It is determined whether Te exceeds the second determination value T2 (step a14).
[0063]
As shown in FIG. 4, since the value of the second determination value T2 is set lower than the value of the first determination value T1, the determination result in step a14 at this stage is normally true. Therefore, the CPU as the damper position control means with the limiting function is the value stored in the execution value storage register θ at the present time, that is, the inside / outside air switching damper 3 obtained in the processing of step a3 or step a4 of the processing cycle. , And a value for continuing to connect the inside / outside air switching damper 3 to the outside air intake 9 side is held in the execution value storage register θ (step a15).
[0064]
Note that this operation is actually a resetting action, not a holding operation, but each processing of step a3, step a4, step a9, and step a15 is a data setting process for executing the swinging process, and actually swings. Since the process is performed in step a13, the change in the register value before that does not affect the actual operation, and this is called resetting as long as there is no change in the value of θ in step a13. It may be referred to as holding instead.
[0065]
Next, the CPU determines whether the air conditioner mode is the manual mode or the automatic operation mode (step a10), and if the air conditioner mode is the automatic operation mode, the CPU executes The air control panel 31 serving as a damper position display means indicates the swing position of the inside / outside air switching damper 3 stored in the value storage register θ, that is, a value indicating that the inside / outside air switching damper 3 is connected to the outside air intake port 9. (Step a11), and when the mode of the air conditioner is in the manual mode, it is stored in the display value storage register θd regardless of the actual swing position of the inside / outside air switching damper 3. The swinging position of the inside / outside air switching damper 3, that is, the swinging position of the inside / outside air switching damper 3 detected in step a4 in the processing cycle is detected. Displayed on the air control panel 31 (step a12).
[0066]
Next, the CPU as the damper position control means with a limiting function selects the value stored in the execution value storage register θ, that is, the swing position for selecting the outside air intake 9 forcibly set in the process of step a15. The actuator 11 is driven and controlled so that the inside / outside air switching damper 3 moves toward (step a13), and the damper position control process in this cycle is finished. However, since the inside / outside air switching damper 3 is already connected to the outside air intake port 9 at this stage, there is no practical operation in the inside / outside air switching damper 3 (the target position and the current position coincide).
[0067]
After that, if the current value Te of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 is not less than the second determination value T2, the damper position control process after the next cycle is performed in the same manner as described above in step a1. To Step a6 (however, Step a2 to Step a3 and Step a4 to Step a5 are alternatives), Step a14 to Step a15, and Step a10 to Step a13 (however, The process of step a11 and the process of step a12 are repeatedly executed, and during this time, the inside / outside air switching damper 3 is held at the position where the outside air intake 9 is selected.
[0068]
As already described, since the value of the second determination value T2 is set lower than the value of the first determination value T1, the current value Te of the blast temperature in the duct 2 is temporarily set to the first determination value. If the temperature zone storage flag F is set beyond T1, even if the current value Te of the blowing temperature in the duct 2 slightly fluctuates, outside air is taken in as long as the value does not fall below the second determination value T2. Forcible release control for is never interrupted.
[0069]
In short, the forced opening control for taking in outside air is performed in the section where the temperature zone storage flag F is set in FIG. 4, and this is the actual state of the hysteresis setting function achieved by the CPU of the control unit 27. It is.
This function prevents inadvertent swinging of the inside / outside air switching damper 3 due to subtle fluctuations in the blowing temperature Te detected by the evaporator temperature sensor 30, and achieves smooth air conditioning control. Durability is also improved. T1 and T2 are both set values in the nonvolatile memory, and can be arbitrarily set as necessary.
[0070]
And while such a process is repeatedly performed, the effect of introducing air from the outside air intake port 9 appears, and the current value Te of the blowing temperature in the duct 2 detected by the evaporator temperature detection sensor 30 is the second determination. When the value falls below the value T2, the CPU constituting the hysteresis setting function realizing means detects this in the discrimination process in step a14, resets the temperature zone storage flag F (step a16), and again determines the damper position command in step a3. The swing control of the inside / outside air switching damper 3 in accordance with the automatic calculation processing of the means or the manual setting operation in step a4 is started.
[0071]
An example of the switching timing from the forced opening control for taking in outside air to the swing control according to the automatic calculation processing or manual setting operation of the damper position command means is shown by a point X2 in FIG.
[0072]
Next, the CPU determines whether the air conditioner mode is the manual mode or the automatic operation mode (step a10), and if the air conditioner mode is the automatic operation mode, the CPU executes When the swing position of the inside / outside air switching damper 3 stored in the value storage register θ is displayed on the air control panel 31 serving as a damper position display means (step a11), and the mode of the air conditioner is in the manual mode In this case, the swing position of the inside / outside air switching damper 3 stored in the display value storage register θd is displayed on the air control panel 31 (step a12).
[0073]
In the damper position control process in the processing cycle, since the process of step a15 is not executed, no special operation is added to the swing position of the inside / outside air switching damper 3, that is, the value of the execution value storage register θ. The value of the execution value storage register θ and the value of the display value storage register θd are the same value.
[0074]
Next, the CPU as the damper position control means with the limiting function is configured so that the inside / outside air is directed toward the value stored in the execution value storage register θ, that is, the swing position obtained in step a3 or step a4 of the processing cycle. The actuator 11 is driven and controlled so that the switching damper 3 moves (step a13), the damper position control process in this cycle is terminated, and the initial state is restored.
[0075]
After that, unless the current value Te of the air temperature in the duct 2 detected by the evaporator temperature detection sensor 30 exceeds the first determination value T1, the process from step a1 to step a7 is performed in the damper position control process after the next period. (However, the processing of step a2 to step a3 and the processing of step a4 to step a5 are alternatives) and the processing of step a10 to step a13 (however, the processing of steps a11 and a12 are alternatives) 1) is repeatedly executed, and the swing control of the inside / outside air switching damper 3 according to the automatic calculation processing of the damper position command means in step a3 or the manual setting operation in step a4 is continuously performed.
[0076]
At this stage, since the temperature zone storage flag F has already been reset, either the automatic calculation process of the damper position command means or the swing control of the inside / outside air switching damper 3 according to the manual setting operation is continued, or The first determination value T1 has already been selected as a determination criterion for determining whether to start the forced release control for taking in outside air anew.
[0077]
The processing when the current value Te of the blowing temperature in the duct 2 detected by the evaporator temperature detection sensor 30 again exceeds the first determination value T1 is as already described.
[0078]
【The invention's effect】
The automotive air conditioner of the present invention blows air from the blower fan to the motor drive circuit when the temperature in the duct exceeds the judgment value, for example, when cooling is started with the inside air circulation selected under hot weather. When the wind temperature rises to a state that is not suitable for forced air cooling, the inside / outside air switching damper is forcibly switched to the outside air intake side ignoring the command position by the damper position command means. Instead of air, fresh fresh air can be sent to the motor drive circuit. As a result, the forced air cooling effect by the blower fan is increased, and it becomes possible to continue the air conditioning process without stopping the blower fan and protecting the motor drive circuit, and the inside of the vehicle can be cooled within a short time. Can be eliminated, and the passenger's discomfort is also eliminated.
Further, since an evaporator temperature sensor is used as a means for detecting the temperature of the air blown to the motor drive circuit, it is not necessary to provide a special temperature detection sensor in the motor drive circuit itself, and the manufacture of the device Cost is reduced.
[0079]
In addition, as a value to be used as a determination value, a first determination value applied to forced switching from the command position by the damper position command means to the outside air intake side and a command by the damper position command means from the outside air intake side The second judgment value applied to the switching to the position is prepared, and a dead zone related to the switching control of the inside / outside air switching damper is provided by a combination of these judgment values, so that the evaporator temperature sensor An inadvertent swinging operation of the inside / outside air switching damper accompanying a change in the detected temperature is prevented, smooth air conditioning control is achieved, and durability of the apparatus itself is improved.
[0080]
Further, since the damper position display means for displaying the damper position commanded by the damper position command means is provided together irrespective of the actual swing position of the inside / outside air switching damper, the inside / outside air is controlled by the damper position control means with a limiting function. Even when the switching damper is forcibly switched to the outside air intake side, the driver can concentrate on driving without knowing the fact and feeling uncomfortable.
[Brief description of the drawings]
FIG. 1 is a functional block diagram schematically showing a main part of an automotive air conditioner according to an embodiment to which the present invention is applied.
FIG. 2 is a block diagram showing an outline of function realization means constituted by a CPU of a control unit, a nonvolatile memory, and the like.
FIG. 3 is a flowchart showing an outline of a damper position control process performed by a CPU of the control unit.
FIG. 4 is a conceptual diagram showing an example of hysteresis (dead zone) set by a hysteresis setting function of a comparison unit. However, the command position is a value that can change itself and is not a fixed value.
[Explanation of symbols]
1 Automotive air conditioner
2 Duct
3 Inside / outside air switching damper
4 Blower fans
5 Evaporator
6 Heater core
7 Air mix damper
8a, 8b, 8c Mode damper
9 Outside air intake
10 Inside air intake
11 Actuator
12 Motor
13 Actuator
14 Defrost outlet
15 Vent outlet
16 Heat outlet
17 Link mechanism
18 Actuator
19 Compressor
20 capacitors
21 Liquid tank
22 expansion valve
23 Electromagnetic clutch
24 engine
25 Inside air temperature sensor
26 Outside air temperature sensor
27 Control unit (control unit, damper position command means, comparison means, damper position control means with limiting function, storage unit, hysteresis setting function realization means)
28 Air mix damper position detection sensor
29 Mode damper position detection sensor
30 Evaporator temperature sensor
31 Air control panel (Damper position display means)
32 Solar radiation sensor
33 Engine water temperature sensor
34 Motor drive circuit

Claims (2)

An automotive air conditioner having an inside / outside air switching damper, a blower fan, and an evaporator in a duct serving as an air passage, and having a damper position command means for commanding a swing position of the inside / outside air switching damper to a control unit thereof In
A motor drive circuit and an evaporator temperature sensor for a motor that drives the blower fan are arranged at a downstream position close to the evaporator, and the duct temperature detected by the evaporator temperature sensor is previously set in the control unit. Comparing means for comparing the magnitude relationship with the set judgment value, and holding the inside / outside air switching damper at the command position according to a command from the damper position command means when the duct internal temperature does not reach the judgment value and a force limiting function with damper position control means for switching the outside air inlet side within the outdoor air switching damper regardless of a command from the damper position command means and the duct temperature exceeds the determination value provided, wherein Regardless of the actual swinging position of the inside / outside air switching damper, the control unit is designated by the damper position command means. Motor-vehicle air-conditioning system damper position display means for displaying to damper position is characterized in that it is juxtaposed.   The comparison means includes a first determination value applied at the time of forced switching of the inside / outside air switching damper from the command position by the damper position command means to the outside air intake side and the command position by the damper position command means from the outside air intake side. A storage unit storing a second determination value applied at the time of switching of the inside / outside air switching damper, and the second determination value as the determination value when the duct internal temperature exceeds the first determination value. The hysteresis setting function of selecting the first judgment value as the judgment value when the temperature in the duct is lower than the second judgment value is provided together with the selection. Automotive air conditioner.

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