JPS5820808B2 - Automotive air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner for an automobile, and particularly to an improvement in a temperature control unit for quickly bringing the room temperature to a set value without causing any transient phenomenon.

FIG. 1 is a schematic diagram showing an example of an air conditioner for an automobile to which the present invention is applied.

This air conditioner uses a cooler 3 to dehumidify and cool air that is sucked into the device from an air intake port 2 by a blower 1, and a part of the cold air coming out of the cooler 3 is passed through a heater 4 to convert it into warm air. , this is mixed with cold air from the cooler 3 and sent to the air outlet 5.
The blowout temperature is adjusted by operating the air mixing door 7 and hot water valve 8 with a negative pressure actuator 6 to change the mixture ratio of hot air and cold air and the hot water flow rate of the heater 4. On the other hand, the blower drive motor 9
The amount of air blown out is adjusted by changing the number of rotations, and the room temperature is controlled by a combination of the two.

FIG. 2 shows the configuration of a temperature control device conventionally used in this type of air conditioner to maintain the room temperature at a set value.

In FIG. 2, 10 is a thermistor serving as a temperature detection section;
Reference numerals 11 and 12 are sliding resistors serving as a temperature setting section, 13 are sliding resistors for feedback, and 14 and 15 are fixed resistors, each of which receives an input signal (resistance value) from the thermistor 10 corresponding to the room temperature.
The deviation between the reference input (resistance value) from the sliding resistor lL12 corresponding to the set temperature is converted into a potential difference between points a and b and between points a and C of a resistor bridge consisting of 10 to 15 and extracted. , to the comparators 16 and 17 of the control section to determine the magnitude and sign of the deviation.

As a result, the obtained control signal is transferred to the amplifying transistor 18.
, 19 into power outputs, and the respective outputs selectively excite coils 20, 21.

A three-way valve 22.23 operated by a coil 20.21 serves to switch the sides of the piston 24 in the vacuum actuator 6 into a vacuum side 25 and an atmospheric side 26.27.

For example, if the room temperature has now fallen below the set temperature,
As the resistance value of the thermistor 10 increases, the potential at point a rises, and the comparator 16 outputs a control signal of 1''.

This signal turns on the transistor 18, and the coil 20
is excited.

Then, due to the operation of the three-way valve 22, one of the pistons 24
Since the side becomes negative pressure, the piston 24 moves to the H side, and the air mixing door 7 and the hot water valve linked thereto (Fig. 1, 8)
Operate in the direction that the blowing temperature increases.

Accompanying this, the resistance value of the feedback sliding resistor 13 increases, pushing up the potential at point b, so that the control system reaches an equilibrium state at a certain point.

That is, the output of the comparator 16 becomes "0", the transistor 18 is turned OFF, and the three-way valve 22 returns to its original state, and the piston 24 stops at that position.

When the room temperature rises above the set temperature, the control signal from the comparator 17 causes the operation opposite to the above to be performed.

If the set temperature is increased, the potential difference between the two points a and b will decrease due to the decrease in the reference input from the sliding resistors 11 and 12. Conversely, if the set temperature is lowered, the reference input from the sliding resistors 11 and 12 will decrease.
．． As the reference input No. 12 increases, the potential difference between the two points a and c changes in the direction of decreasing.

On the other hand, when the contact 29 of the sliding resistor 28 switches the contact 30 in conjunction with the air mixing door 7, the voltage applied to the blower drive motor 9 changes, changing the number of revolutions and therefore the air volume. As the door 7 moves from the neutral position P1 to the maximum heating position P2 or the maximum cooling position P3 in FIG. 1, the air volume increases.

In this way, temperature control is performed to make the room temperature match the set temperature, but the above-mentioned conventional device has the following problems.

The curve ■ in FIG. 6 shows the transient characteristics of the conventional device when the room temperature reaches the set temperature T2 from the initial temperature T□.

If the temperature difference between T1 and T2 is greater than a predetermined value T3,
If you shorten the time it takes for the room temperature to reach the set temperature, transient phenomena (hunting) are likely to occur near the set temperature.
Conventionally, the output was suppressed during control by reducing the temperature change when the room temperature transitioned from T1 to T2, as shown by the curve ■, and smoothly settling down to the set temperature. When the difference between the room temperature and the set temperature is large, the time t□ for the room temperature to reach the set temperature tends to be long.

In view of the above points, the present invention provides an automobile equipped with an automatic control function that allows the room temperature to quickly reach the set temperature without causing a transient phenomenon when there is a large difference between the room temperature and the set temperature, such as when starting the vehicle. The purpose of this project is to provide an air conditioner for

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing the configuration of the outlet temperature control section of the air conditioner according to the present invention, with the same reference numerals attached to the same parts as in FIG. 2.

In the figure, 31 is a control circuit provided in the present invention, including an absolute value conversion circuit 32, voltage dividing resistors 33, 34, 35, 36, comparators 37 and 38, AND circuits 39 and 40, and NOT circuit 4.
1 and a transistor 42°4.
3 switching means.

This control circuit operates as follows. The potential change at point a corresponding to the deviation between the temperature set by the temperature setting sliding resistor 11 and the room temperature detected by the thermistor 10 is converted into an absolute value by the absolute value conversion circuit 32, and the deviation signal and the resistance 33.
Compare the potential at point d divided by 34 with comparator 3T,
It is determined whether the deviation signal is greater than or equal to a predetermined value determined by the potential at point d.

On the other hand, a comparator 38 compares the potential at point a and the potential at point e divided by resistors 35 and 36, and determines whether the deviation signal is positive or negative.
That is, it is determined whether the room temperature is lower or higher than the set temperature.

When the deviation signal is smaller than the predetermined value, the output of the comparison circuit 37 is 0'', so the outputs of the AND circuits 39 and 40 are also 0.
'', both transistors 42 and 43 are OFF.
in a state.

In this state, sliding resistors 12, 13, fixed resistors 14, 1
5, comparators 16 and 17, and transistors 18 and 19 perform normal control operations similar to the device shown in FIG. Move to the H side or L side to maintain the room temperature at the set temperature.

When the deviation signal from the absolute value conversion circuit 32 is greater than a predetermined value (T3 in FIG. 6), the comparator 37 produces an output of 1''.

At this time, if the room temperature is lower than the set temperature, the comparison circuit 38
Since an output of 1" is generated from , the output of the AND circuit 39 becomes 1", and this signal turns on the transistor 43, shorting the sliding resistor 12.13 and lowering the potential at point b and lowering the potential at point C. Set to zero potential.

Therefore, the comparator 16 continues to output an output of ``1'' until the deviation signal from the absolute value conversion circuit 32 falls below the voltage at point d and the output of the comparator 37 becomes 1'0''.

Therefore, the coil 20 is energized and the three-way valve 22 is switched to lower the piston 24 and move the air mixing door 7 to the maximum heating position P2 and fix it there.

As a result, the blowing temperature rises to the maximum temperature, causing the room temperature to rise rapidly.

Conversely, when the room temperature is higher than the set temperature and the deviation signal from the absolute value conversion circuit 32 is equal to or higher than the predetermined value, the output of the comparator 38 is 0'';1''' is input to , and this and 1 from comparator 37
An output of 1'' is produced in the AND circuit 40 with the input of ``.''.

This signal turns on the transistor 42 and short-circuits the resistor 14, so that the potential at point b becomes the power supply voltage V, and the potential at point C rises.

Therefore, until the deviation signal falls below a predetermined value, the comparator 17 continues to output the output of P1'''.

Therefore, the coil 21 is energized, the three-way valve 23 is switched, the piston 24 is raised, the air mixing door 7 is moved to the maximum cooling position P3, and it is fixed at this position.

As a result, the blowing temperature is lowered to the lowest temperature, and the room temperature is rapidly lowered.

In this embodiment, when the deviation between the room temperature and the set temperature becomes smaller than a predetermined value determined by the potential at point d, normal control operation is resumed to prevent the occurrence of transient phenomena (bunching) near the set temperature. .

By performing such control, the curve ■
As shown, even when the difference between the initial temperature TI and the set temperature T2 is large, the room temperature can quickly reach the set temperature without causing a transient phenomenon, and the transient time t2 can be shortened.

In this case, the temperature when returning to normal control can be set arbitrarily; for example, an AND circuit 39.40
If the output of is held in a separately provided memory circuit, and if the memory circuit is configured to be reset when the deviation between the room temperature and the set temperature becomes less than a separately determined value, the set temperature as shown in T4 in Fig. It is also possible to return to normal control at a point close to .

FIG. 4 shows an example of the configuration of the air volume control section of the air conditioner according to the present invention.

In FIG. 4, the potential change at point a corresponding to the deviation between the temperature set by the temperature setting sliding resistor 11 and the room temperature detected by the thermistor 10 is converted into an absolute value by an absolute value conversion circuit 44.

The comparator 48 generates an output of tt 1pp when the deviation signal from the absolute value conversion circuit 44 becomes equal to or higher than the potential at the voltage dividing point f formed by the resistors 45, 46, 47, and the comparator 49 outputs When the potential exceeds g, an output of '1' is produced.

54 is a control circuit provided in the present invention, and the comparator 5
5 produces an output of '1' when the deviation signal exceeds the potential of the voltage dividing point by the resistors 56 and 57.

Here, the potentials at the voltage dividing points f, g, and h are set to α1. α2
If ゜α3, then the relationship is α1〈α2〈α3.

Resistors 50°51.
The potential at the voltage dividing point i of 52.53 changes as follows.

In other words, the potential at the voltage dividing point i is
It is lowest when all outputs tt - On are in the state, and becomes higher stepwise as the outputs of the comparators 48, 49.55 sequentially reach It 1fij.

As the potential at the voltage dividing point i changes, the current flowing from the voltage dividing point i into the base of the control transistor 58 connected to the circuit of the blower driving motor 9 changes, and the voltage applied to the motor 9 changes. .

As a result, the rotational speed of the motor 9, and therefore the amount of air blown, changes in stages.

Figure 5 is a diagram showing the relationship between deviation and air volume.
The deviation changes stepwise from 1 to 1 until it reaches α1, M1 when the deviation reaches from α1 to α2, and M2 when the deviation goes from α2 to α3.

L, Ml, and M2 are normal control areas, and when the deviation is greater than or equal to the predetermined value α3, the air volume becomes the maximum value H, and the deviation is α3.
This state continues until it becomes smaller.

Among them, when the output of the comparator 55 becomes 1'' in FIG. 4, the output turns on the transistor 59 and excites the coils 60 and 61.

The coil 60.61 is the blowout rod door 62.63 in Fig. 1.
is moved to the dotted line position, the air outlet 5 is fully opened, and a state corresponding to maximum heating or maximum cooling is achieved.

As explained above, the present invention operates an air conditioner from when the deviation between the temperature set by the cabin temperature setting section and the cabin temperature becomes a predetermined value or more until the predetermined temperature reaches a predetermined temperature that does not reach the set temperature. Since it operates at maximum heating capacity or maximum cooling capacity, even when there is a large difference between the room temperature and the set temperature,
The room temperature can rapidly reach the set temperature without causing any transient phenomenon, and the temperature control function of the automotive air conditioner can be further improved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an air conditioner to which the present invention is applied;
The figure is a block diagram of a temperature control device used in a conventional air conditioner, FIG. 3 is a block diagram showing an example of the outlet temperature control device in the air conditioner of the present invention, and FIG. 4 is a block diagram of an air volume control device. FIG. 5 is an explanatory diagram of the operation of the air volume control device shown in FIG. 4, and FIG. 6 is an explanatory diagram showing the transient characteristics of the conventional device and the device of the present invention. 1: Blower, 2: Air intake, 3: Cooler, 4: Heater, 5: Air outlet, 6: Negative pressure actuator, 7: Air mixing door, 8: Hot water valve, 9: Blower drive motor, 1
0: Vehicle interior temperature detection section, 11: Vehicle interior temperature setting section, 12-1
9: Blowout temperature control section, 31: Control circuit, 32-41:
Actuation signal output circuit, 42. 43 Transistor serving as a switching means, 44 to 53: Blowout air volume control unit, 54
: Control circuit.

Claims (1)

[Claims] 1. It has a blowout temperature control section that detects the deviation between the set temperature and the cabin temperature and operates the actuator of the air mixing door in a direction to eliminate the deviation, and the air mixing door controls the mixing ratio of hot air and cold air. In an automotive air conditioner that adjusts and controls the blowout temperature, the vehicle interior temperature remains at the set temperature from the time the deviation becomes equal to or higher than the predetermined value until the vehicle interior temperature reaches a predetermined temperature at which the temperature does not reach the set temperature. an operation signal output circuit that outputs a signal that instructs an air conditioner to operate at its maximum heating capacity or maximum cooling capacity depending on whether the temperature is lower or higher than the temperature; and a signal that instructs it to operate at its maximum heating capacity or maximum cooling capacity. is provided with a control circuit having switching means for controlling the output of the blowout temperature control section such that the actuator moves the air mixing door to a maximum heating position or a maximum cooling position and fixes it at that position while the air mixing door is inputted. An automotive air conditioner featuring: