JPH0341929Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an air conditioner for an automobile that can automatically adjust the temperature inside the vehicle.

(Prior Art) As shown in FIG. 4, a typical automobile air conditioning system includes an intake unit 1 that takes in air from inside and outside the vehicle interior using a fan 4, and an evaporator 5 that takes in the air from the intake unit 1. A cooler unit 2 that cools the vehicle by heat exchange, and all or part of the air cooled by the cooler unit 2 is guided to the heater core 7 through a mixer door 6 and heated, or all of the cooled air is bypassed from the heater core 7 to cool the vehicle. It has a heater unit 3 that blows out air into the room.

In order to automatically adjust the temperature inside the vehicle to the temperature set by the occupant using such an air conditioner for a vehicle, the opening and closing of the mixer door 6 is automatically controlled according to the temperature inside and outside the vehicle, and the heater unit 3 It is necessary to control the temperature of the air blown into the vehicle interior. Conventionally, a negative pressure actuator or the like has been used as a drive source for opening and closing such a mixer door 6, but in recent years, step motors 8 have come to be used in order to make the control more accurate. Ta.

This step motor 8 rotates a rotating shaft 9 by a predetermined angle, thereby connecting a link 10 and a rod 11.
The mixture door 6 is rotated by a predetermined angle through the . The step motor 8 is connected to a microcomputer 12 and controlled by the microcomputer 12.

The microcomputer 12 uses outside air sensors 13 and 14 to detect the temperature of the outside air, an inside air sensor 15 to detect the temperature inside the vehicle, a solar radiation sensor 16 to detect the amount of solar radiation, and the temperature of the air blown out from the evaporator 5. Intake sensor 17 to detect
a variable resistor PTC that sets the cabin temperature desired by the occupant, and a variable resistor that is linked to the link 10 and detects the opening degree of the mixer door 6.
It is connected to the PBR, and electrical signals from various sensors and variable resistors are input.
In addition, this microcomputer 12 has a power supply 1
8 via an ignition switch 19 and an accessory circuit 20. The ignition switch 19 is a switch for starting the automobile, and the accessory circuit 10 is a circuit that supplies current to interior accessories (interior lights, radio, etc.) of the vehicle.

(Problem to be solved by the invention) However, in the control device of such an automobile air conditioner, since the variable resistor PBR detects the position of the mixer door 6, this variable resistor
The control characteristics are limited by the resistance error (approximately ±10%) of the PBR, and even though the step motor 8 is adopted for more accurate control, the opening degree of the mix door 6 is limited by the resistance of the PBR. There were only errors.

The present invention was developed in view of these circumstances, and aims to reduce the opening error of the mixer door,
The opening of the mixer door is controlled more accurately, and the temperature of the air blown into the cabin is more accurately controlled.
The purpose is to quickly bring the temperature inside the vehicle close to the set temperature with good control characteristics, and to achieve comfortable air conditioning for the vehicle.

(Means for Solving the Problems) In order to achieve this purpose, the present invention has various sensors connected to a step motor that controls the opening degree of the mixture door that changes the temperature of the air blown into the vehicle interior. In the automotive air conditioner controlled by a microcomputer, an auxiliary power supply circuit that constantly supplies current to a memory circuit in the microcomputer that stores the opening degree of the mixer door is connected to an auxiliary power supply circuit that supplies current to the entire microcomputer. The microcomputer is characterized in that the microcomputer is provided with a current cutoff detection means that is formed separately from the main power supply circuit and detects that the current flowing through the auxiliary power supply circuit is cut off.

(Function) In such an automotive air conditioner, it is possible to constantly store the current opening degree of the mixer door in the memory circuit as the rotation angle of the step motor. No need for resistor PBR.

In this way, if the variable resistor PBR to detect the mix door position is no longer necessary, this variable resistor
The resistance error of PBR is eliminated, allowing accurate mix door opening control.

In addition, if the stored contents of the memory circuit are erased when replacing the power supply, etc., it can be detected and necessary measures can be taken, so there are no inconveniences caused by the erased contents of the memory circuit. Nor.

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

FIG. 1 is an overall schematic diagram showing an automotive air conditioner and its control device according to the present invention, and FIG.
A block diagram of the control device shown in Fig. 3 is shown in Fig. 1.
This is a flowchart showing a control method of the control device shown in FIG. 2, in which members common to those shown in FIG. 4 are given the same reference numerals, and some explanations thereof are omitted.

As shown in FIG. 2, the microcomputer 12a according to the present invention includes an input port 30 into which output signals from the variable resistor PTC, the outside air sensors 13, 14, the inside air sensor 15, the solar radiation sensor 16, and the intake sensor 17 are input. A memory circuit 31 as a RAM that stores data only while current is supplied, and an output port that processes signals from the input port 30 and the data stored in the memory circuit 31 and outputs the results. It has a central processing unit CPU which outputs output to the step motor 8 via 32. Although not shown, a memory circuit as a ROM is also connected to this central processing unit CPU.

In particular, in the present invention, the auxiliary power supply circuit 33 for constantly supplying current to the memory circuit 31 is
The same power supply 18 is connected in parallel with the main power supply circuit 34 that supplies current to the entire microcomputer 12a.
is connected to. The main power circuit 34 includes an ignition switch 19 that starts the engine, and an accessory circuit 2 that supplies current to automotive accessories.
0 is formed, and the ignition switch 1
When 9 goes out, the memory circuit 31 and reset circuit 35
The current is not allowed to flow through the microcomputer 12a except for the microcomputer 12a.

A reset circuit 35 is connected to the auxiliary power supply circuit 33 as a current cutoff detection means for detecting that the current flowing through the auxiliary power supply circuit is cut off. This reset circuit 35 is used when even the current flowing to the auxiliary power supply circuit 33 is cut off and then turned on, such as when replacing the power supply 18.
It functions to output a signal for resetting (resetting) the memory contents of the memory circuit 31 to the memory circuit 31.

Next, a control method of such a control device will be explained based on the flowchart shown in FIG.

First, when the ignition switch 19 is turned on to operate the control device, it is detected in step 40 whether the contents stored in the memory circuit 31 have been reset. The case where the memory content of the memory circuit 31 is reset is when the power supply 18 is replaced, and the memory content of the memory circuit 31 is not reliable.
The step motor 8 is connected to the step motor 8 through the output port 32.
Then, a drive pulse signal is outputted to rotate the mixer door 6 to the full cool position, which is the initial position.

The full cool position is a state in which the mixer door 6 is rotated to the A position in FIG. The number of driving pulses for rotating the mixer door 6 to the full cool position is set to a large number so that the mixer door 6 can return to the full cool position even if it is in the full hot position (position B in the figure). When it is in position, the rotation axis is designed to rotate idly.

Next, in step 42, the current mix door 6
0 in the register θ ₁ that stores the numerical value representing the opening degree as an angle from the full cool position (position A in the figure).
Enter. A state in which 0 is input to this register θ ₁ indicates that the mix door 6 is at the full cool position. Next, in step 43, the variable resistance PTC represents the desired temperature set by the occupant as a resistance value, and in step 44, the respective electrical signals from various sensors are inputted to the CPU from the input port 30, and the CPU blows air into the passenger compartment. The required blowing air temperature is calculated (step 45). Next, the required opening degree of the mixer door corresponding to this required blowing air temperature is calculated, and the value is input into the register θ ₂ (step 46).

Next, the value of the register θ ₁ indicating the current mix door opening degree is retrieved from the memory circuit 31 (step 47), θ ₂ - _{θ 1} is calculated, and this value of θ ₂ - _{θ 1} is used to drive the step motor. Convert to pulse (step 48). If the drive pulse obtained in this way is output to the step motor 8 via the output port 32 (step 49), the step motor 8 will rotate at a rotation angle corresponding to the drive pulse, and at the same time, the mix door 6 will also rotate. , the mix door 6 stops at the mix door required opening degree _θ2 . in this case,
The error between the actual mix door opening degree and the mix door required opening degree θ ₂ is determined by the rotation angle error of the step motor with respect to the drive pulse, and is an error of ±0.5% or less.

Next, in step 50, the contents of register θ ₂ indicating the required opening degree of the mix door are replaced with register θ ₁ indicating the current mix door position. By doing so, the current mix door position can be stored in the register θ ₂ in the memory circuit 31.

Next, in step 51, it is detected whether or not the ignition switch 19 for starting the engine is turned off. If the ignition switch 19 is not turned off, the process returns to step 40 and the above-described control is performed again. Repeat this to bring the temperature inside the vehicle closer to the predetermined temperature desired by the occupants.

According to such control, the memory circuit 31 always remembers the current mix door opening, so the mix door opening error is ±0.5%.
The opening error of the conventional mix door is approximately ±
Accuracy is significantly improved compared to 10%.

(Effects of the invention) As described above, according to the invention, the step motor that controls the opening degree of the mixer door that changes the temperature of the air blown into the vehicle interior is controlled by a microcomputer connected to various sensors. In an automotive air conditioner, an auxiliary power supply circuit that constantly supplies current to a memory circuit in the microcomputer that stores the opening degree of the mixer door is a main power supply circuit that supplies current to the entire microcomputer. Since the microcomputer is provided with a current cutoff detection means which is formed separately and detects that the current flowing through the auxiliary power supply circuit is cut off, the current mix door opening degree can be stored in the memory circuit sequentially. This makes it possible to control the opening of the mixer door with high precision. Furthermore, even if the contents of the memory circuit should be erased, this can be detected and the mix door can be returned to its initial position, thereby preventing malfunctions. Therefore, the temperature of the air blown into the vehicle interior can be controlled more accurately, the temperature inside the vehicle interior can quickly approach the set temperature with good control characteristics, and comfortable air conditioning for the vehicle can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram showing an automotive air conditioner and its control device according to the present invention, and FIG.
A block diagram of the control device shown in Fig. 3 is shown in Fig. 1.
FIG. 2 is a flowchart showing a control method of the control device shown in FIG. 2, and FIG. 4 is an overall schematic diagram showing a conventional automobile air conditioner and its control device. 6...Mix door, 8...Step motor,
12, 12a...microcomputer, 13,
14...Outside air sensor, 15...Inside air sensor, 16
...Solar radiation sensor, 17...Intake sensor, 18...
Power supply, 31...Memory circuit, 33...Auxiliary power supply circuit, 34...Main power supply circuit, 35...Reset circuit.

Claims (1)

[Scope of utility model registration request] In an automobile air conditioning system, the opening degree of the mixer door is memorized in an automotive air conditioning system in which a step motor that controls the opening degree of the mixer door that changes the temperature of the air blown into the vehicle interior is controlled by a microcomputer to which various sensors are connected. An auxiliary power supply circuit that constantly supplies current to a memory circuit in a microcomputer that is running is formed separately from a main power supply circuit that supplies current to the entire microcomputer, and the current flowing to the auxiliary power supply circuit is cut off. An air conditioner for an automobile, characterized in that the microcomputer is provided with current interruption detection means for detecting current interruption.