JP2000301934A - Compressor controller for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a required operation frequency without applying an excessive load to a compressor even when a rotational speed of a fan is changed. SOLUTION: A refrigerant is circulated from a heat-absorbing in-room heat exchanger 14 to a heat-radiating in-room heat exchanger 15 by driving a compressor 16, passing through or not passing through an out-door heat exchanger 18 by switching a four-way valve 17. The compressor 16 is driven at an operation frequency provided by adding a proportional value of a difference hereinafter to an integrated increase and decrease value, based on the difference between a target blast temperature and an actual blast-air temperature of the heat exchanger 15, at the time of heating. Since an upper limit of the operation frequency is not fixed even when a rotational speed of a fan 12 is switched and since the operation frequency is determined based on the difference between the target blast temperature and the actual blast-air temperature, excessive pressure is not generated ranging from the heat exchanger 15 to the compressor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor control device for an air conditioner mounted on a vehicle, for example.

[0002]

2. Description of the Related Art A conventional air conditioner is disclosed in, for example,
There is a vehicle as disclosed in Japanese Patent Publication No. 118126. FIG. 4 shows the refrigerant system. A heat absorbing indoor heat exchanger 14 and a heat radiating indoor heat exchanger 15 are provided in the vehicle cabin, and the suction side of the compressor 16 is connected to the outlet of the heat absorbing indoor heat exchanger 14 via a check valve 24 and discharged. Each side is connected to the suction side of the compressor 16 itself via a four-way valve 17, the inlet of the outside heat exchanger 18, and the inlet of the radiating indoor heat exchanger 15 via a check valve 20.

The outlet of the heat exchanger 15 is connected to the outlet of the heat exchanger 18 through a check valve 19. A refrigerant tank 21 and an expansion valve 22 are sequentially provided between the outlet of the indoor heat exchanger 15 for heat radiation and the inlet of the indoor heat exchanger 14 for heat absorption. Indoor heat exchanger 14 for heat absorption
The heat is exchanged between the air and the air that is introduced with the fan 12 ′ attached to the indoor heat exchanger 15 for heat radiation.

During the heating operation, the four-way valve 17 is set to the position shown by the solid line, and the refrigerant flows from the compressor 16 to the four-way valve 17,
Check valve 20, indoor heat exchanger 15 for heat radiation, refrigerant tank 2
1, the expansion valve 22, the indoor heat exchanger for heat absorption 14, and the compressor 16 flow and circulate in this order. As a result, the air introduced by the fan 12 'is cooled by the indoor heat exchanger 14 for heat absorption, and then heated by the indoor heat exchanger 15 for heat radiation to become hot air for vehicle interior heating.

During the cooling operation, the four-way valve 17 is in the position shown by the broken line, and the refrigerant flows from the compressor 16 to the four-way valve 17,
The heat exchanger 18 circulates in the order of the exterior heat exchanger 18, the check valve 19, the heat radiation indoor heat exchanger 15, the refrigerant tank 21, the expansion valve 22, the heat absorption indoor heat exchanger 14, and the compressor 16. As a result, the heat of the high-temperature refrigerant discharged from the compressor 16 is radiated by the heat exchanger 18 outside the vehicle, and the fan 1
The air introduced at 2 'is cooled by the heat absorbing indoor heat exchanger 14, and becomes cold air for vehicle interior cooling.

[0006] Such an air conditioner has an advantage that it can perform cooling and heating even in an electric vehicle or the like that does not have a large heat source such as cooling water for an internal combustion engine, and can perform dehumidifying heating.

In an electric vehicle, the main motor stops when the vehicle stops, so that the compressor 16 is driven by another submotor. Recently, however, a hybrid vehicle with an internal combustion engine or a vehicle with an internal combustion engine also has the same configuration.
The compressor drive by the sub motor is selected. Thereby, the operating frequency of the compressor can be appropriately controlled.

Generally, an air conditioner is capable of controlling the amount of air blown out, and even an air conditioner mounted on a vehicle is provided with a fan switch that can be arbitrarily operated by an occupant. That is, for example, a selectable fan switch is provided from the lowest speed first speed to the highest speed fourth speed,
The rotation speed of the fan attached to the heat exchanger is changed by switching the fan switch.

[0009]

However, when the fan switch is switched from the highest speed, for example, the fourth speed to the lowest speed, ie, the first speed, in order to reduce the amount of blown air during heating by the air conditioner, the room heat for radiating heat is reduced. A phenomenon occurs in which the amount of heat released from the exchanger decreases, and the refrigerant pressure rapidly increases.

To cope with this, it is conceivable to set an upper limit value for the operating frequency of the compressor 16 for each speed of the fan switch. For example, as shown in FIG. 5, in the fourth speed, the compressor operates at a frequency up to 120 Hz, but in the first speed, the operating frequency is suppressed to a maximum of 80 Hz.

However, since these upper limit values are set to prevent a rapid rise in the refrigerant pressure when the rotation speed of the fan is changed, if the values are fixed, the first speed is increased from the beginning. Even when the operating frequency of 120 Hz is required in the initial warm-up period of the selected operation, the frequency is limited to a low frequency of, for example, 80 Hz. On the other hand, when the speed is switched from the fourth speed to the first speed, even if the frequency is limited to 80 Hz, it cannot yet cope with the increase in the refrigerant pressure depending on the environmental conditions.
In some cases, an excessive load is applied to the compressor 16.

That is, the required operating frequency varies in response to changes in the environment, changes in the target temperature, and the like. Even when the fan switch is switched to change the rotation speed of the fan, the appropriate upper limit value changes depending on, for example, the temperature in the vehicle compartment at that time. Therefore, when trying to control the operating frequency after the switching of the fan rotation speed in consideration of the above, there arises a problem that many maps as shown in FIG. 6 must be prepared.

Accordingly, the present invention has been made in consideration of the above problems, and has been made in consideration of the above-described problems. The purpose of the present invention is to provide a compressor control device for a machine.

[0014]

Therefore, according to the present invention, the refrigerant is circulated to the outdoor heat exchanger and the indoor heat exchanger by driving the compressor, and the indoor heat exchanger is connected to the suction side of the compressor. A connected endothermic indoor heat exchanger,
In the air conditioner consisting of a radiating indoor heat exchanger connected to the discharge side of the compressor without passing through the outdoor heat exchanger at the time of cooling, through the outdoor heat exchanger during heating by the switching valve,
During heating, the compressor is driven at an operating frequency based on the difference between the target outlet temperature and the actual outlet air temperature of the indoor heat exchanger for heat radiation, for example, an operating frequency of a value calculated by adding a proportional value of the difference or an integral increase / decrease value. It was to be done.
Since the operating frequency of the compressor is determined based on the difference between the target outlet temperature and the actual outlet air temperature of the indoor heat exchanger for heat radiation, the operating frequency is not fixed by the fan rotation speed, and the Do not apply excessive load.

According to a fourth aspect of the present invention, an upper limit is set to the target outlet temperature when a predetermined low-speed rotation speed is selected by a fan switch for a fan attached to the indoor heat exchanger. It was done. Since the upper limit is set for the target outlet temperature, the operating frequency of the compressor is reduced as compared with the case of the highest speed of the fan, and the operation becomes quieter in proportion to the fan rotation speed.

[0016]

Embodiments of the present invention will be described below with reference to examples. FIG. 1 is a diagram showing an embodiment in which the present invention is applied to an air conditioner mounted on a vehicle. The refrigerant system is the same as that shown in FIG. An indoor heat exchanger 14 for heat absorption and an indoor heat exchanger 15 for heat radiation are sequentially arranged in the duct 10, and the air introduced by the fan 12 passes through the indoor heat exchanger 14 for heat absorption and is selectively provided by the door 11. It passes through the indoor heat exchanger 15 for heat radiation.

The compressor 16, the four-way valve 17 and the fan motor 13 are controlled by a control device 30. The controller 30 is connected to a blow mode switch 31 and an operation mode switch 32, and switches the air intake port and the blow port of the duct 10 and switches between the cooling operation and the heating operation based on the operation of each switch. Although these configurations and operations are general, the details are described in
Reference is made to Japanese Patent Publication No. 8126, and the illustration is omitted.

A heat-absorbing indoor heat exchanger suction air temperature sensor 33 and a heat-absorbing indoor heat exchanger blow-off air temperature sensor 34 are provided before and after the heat-absorbing indoor heat exchanger 14. Is provided with a blow-out temperature sensor 35 for the indoor heat exchanger for heat radiation. Each of these sensors is connected to the control device 30. In addition, a room temperature sensor 36, an outside air temperature sensor 37, and a room temperature setting device 38 provided on an instrument panel.
And a fan switch 39 are connected to the control device 30. The fan switch 39 can select from a first speed, which is the lowest speed, to a fourth speed, which is the highest speed.

The control device 30 switches the four-way valve 17 according to the cooling and heating operation modes to switch the refrigerant circulation path. The sensors 33, 34, 35, 36, 37 correspond to the temperatures set by the room temperature setting device 38.
Calculates the target value (target blow-off temperature) of the blow-out temperature as the air conditioner based on the input data from the CPU and the state of the fan switch 39 to determine the operating frequency of the compressor 16.

During this time, the fan 12 is driven to rotate by the fan motor 13 at a speed selected by the occupant using the fan switch 39. When heating is selected by the operation mode switch 32, the door 11 is driven to the imaginary line position in the duct 10, and all the air passing through the indoor heat exchanger 14 for heat absorption passes through the indoor heat exchanger 15 for heat radiation. Shall be used.

Next, the control operation of the control device 30 during the heating operation will be described with reference to the flowchart of FIG. When heating is selected by the operation mode switch 32, first, in step 101, the heat absorption indoor heat exchanger suction air temperature sensor 33, the heat absorption indoor heat exchanger blow air temperature sensor 34, and the heat dissipation indoor heat exchanger blow air temperature. Sensor 35, room temperature sensor 36, outside temperature sensor 3
7, and the data from the room temperature setting unit 38 is read.

Then, in step 102, based on the data from the sensors and the room temperature setting unit 38,
The target outlet temperature TO immediately after the heat-radiating indoor heat exchanger 15 is calculated. Next, at step 103, it is checked whether the fan switch 39 is in any one of the first to third speeds. If the fan switch 39 is in any one of the first to third speeds, the process proceeds to step 104, where it is checked whether the calculated target outlet temperature TO exceeds 50 ° C.

If the target outlet temperature TO does not exceed 50 ° C., in step 105, the target outlet temperature upper limit TOmax
= TO, and in step 107, the temperature deviation eTO is calculated. If it is determined in step 103 that the fan switch is in the fourth speed, the process proceeds to step 105. On the other hand, if the target outlet temperature TO exceeds 50 ° C. in the check in step 104, the process proceeds to step 107 after fixing TOmax = 50 (° C.) in step 106.

In step 107, the temperature deviation amount is obtained by eTO = TOmax-Tsc, where Tsc is the temperature detected by the air temperature sensor 35 for the heat radiation indoor heat exchanger. The operating frequency of the compressor 16 is determined as a function of this eTO. That is, in step 108, the integral increase / decrease value dIH is obtained by dIHz = (K1 / Ti) * eTO, and in the next step 109, the proportional value PHz is obtained by PHz = K1 * eTO. Note that K1 and Ti are predetermined coefficients.

Then, in step 110, the operating frequency of the compressor 16 is calculated as PIHz = PHz + dIHz. In step 111, the compressor 16 is driven according to the operating frequency calculated above. The above flow is repeated, for example, in a one-second cycle, and the operating frequency of the compressor 16 smoothly changes according to the temperature change of each part detected by each sensor.

Next, the state of the change in the operating frequency will be described with reference to FIG. The figure shows a change in the blown air temperature Tsc of the indoor heat exchanger 15 for heat radiation for each rotation speed of the fan 12. Here, when the fan 12 is initially driven at the third speed, the blown air temperature Tsc changes along the third speed line in the drawing, for example, toward the upper limit of 50 ° C. (TOmax). At time t1, the blown air temperature is A (= Ts
c (t13)), the temperature deviation calculated in step 106 is eTO (t13) = 50−A. Therefore, the operating frequency of the compressor 16 at this time is: PIHz = PHz + dIHz = K1 * eTO (t13) + (K1 / Ti) * eTO
(T13).

At this time t1, the driver sets the fan switch 3
9 is switched to the first speed, the blowing air temperature Tsc
Moves to the first speed line, and the temperature of the blown air from the indoor heat exchanger for heat radiation 15 changes to B (= Tsc (t11)). As a result, the temperature deviation becomes eTO (t11) = 50−B. As a result, the operating frequency of the compressor 16 becomes PIHz = K1 * eTO (t11) + (K1 / Ti) *
eTO (t11). This value is because the value of B is greater than A
It is lower than before the fan switch 39 was switched.

In the above description, the target outlet temperature is fixed at 50 ° C. In other words, when the indoor temperature is low at the beginning of heating, the target outlet temperature TO is high and the actual outlet air temperature Tsc is low. The 16 operating frequencies PIHz are set high. When the heating is stabilized, the target outlet temperature TO is reduced, and the fan switch 39 is switched to the low speed side. When the actual outlet air temperature Tsc is increased, the operating frequency PIHz of the compressor 16 is reduced.

This embodiment is constructed as described above, and calculates the operating frequency PIHz of the compressor 16 based on the difference between the target outlet temperature TO and the actual outlet air temperature Tsc of the indoor heat exchanger 15 for heat radiation. So fan switch 3
The compressor 16 is operated at an appropriate frequency irrespective of the presence or absence of the switching of No. 9. That is, even when the fan switch 39 is switched, the operating frequency of the compressor 16 is obtained by the same calculation in consideration of the target outlet temperature TO and the outlet air temperature Tsc, so that the operating frequency is not fixed at each speed. Frequency is secured, and an excessive load is not applied to the compressor 16.

When the fan switch 39 is in any one of the first speed to the third speed and is not the fourth speed, which is the highest speed, the upper limit is set to the target blowing temperature. The difference becomes small, and the operating frequency PIHz of the compressor 16 is also reduced as compared with the case of the highest speed of the fan, and the operation becomes quieter in proportion to the fan rotation speed.

In the above embodiment, the fan switch 39
Are from the first speed to the fourth speed, but the number of gears is not particularly limited. Auto (Auto)
o) A position may be provided, and when the auto is selected, the rotation speed of the fan 12 may be changed according to the blown air temperature. Also in this case, since the blow-off air temperature Tsc changes according to the rotation speed, an appropriate operating frequency of the compressor 16 is determined correspondingly.

In the embodiment, all the air that has passed through the indoor heat exchanger 14 for heat absorption during the heating operation passes through the indoor heat exchanger 15 for heat dissipation. When the door 11 is controlled so that a part of the air that has passed through the indoor heat exchanger 14 passes through the indoor heat exchanger 15 for heat radiation, the indoor heat exchanger 14 for heat absorption may be used instead of the blowout air temperature Tsc. The difference between the temperature TMIX at the point where the air that has passed through the air and the air that has passed through the heat-radiating indoor heat exchanger 15 are mixed and the target outlet temperature TO may be used as the temperature deviation. Therefore, in the present invention, the blowout air temperature includes TMIX. Furthermore, although the embodiment has described the air conditioner mounted on the vehicle, the present invention is not limited to the vehicle.

[0033]

As described above, in the present invention, the refrigerant is circulated to the outdoor heat exchanger and the indoor heat exchanger by driving the compressor, and the indoor heat exchanger is connected to the indoor heat exchanger for heat absorption connected to the suction side of the compressor. In an air conditioner consisting of an heat exchanger and a switching valve, the air conditioner consists of an outdoor heat exchanger during cooling and an indoor heat exchanger for heat radiation connected to the discharge side of the compressor without passing through the outdoor heat exchanger during heating. Sometimes, the compressor is driven at an operating frequency based on the difference between the target outlet temperature and the actual outlet air temperature of the indoor heat exchanger for radiation, so the required operating frequency is secured without being fixed by the fan rotation speed. In addition, there is an effect that an excessive load is not applied to the compressor.

When a predetermined low-speed rotation speed is selected by a fan switch for a fan attached to the indoor heat exchanger, an upper limit is set for the target blow-out temperature, so that the operating frequency of the compressor is reduced. The operation is reduced as compared with the case of the maximum speed of the fan, and a quiet operation corresponding to the rotational speed of the fan can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a flow of a control operation in the embodiment.

FIG. 3 is an explanatory diagram showing a change in blown air temperature of an indoor heat exchanger for heat dissipation.

FIG. 4 is a diagram showing a refrigerant system.

FIG. 5 is a diagram showing an example of a conventional upper limit setting of a compressor operating frequency.

FIG. 6 is a diagram showing another example of setting the upper limit of the conventional compressor operating frequency.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Duct 11 Door 12 and 12 'Fan 13 Fan motor 14 Indoor heat exchanger for heat absorption 15 Indoor heat exchanger for heat dissipation 16 Compressor 17 Four way valve 18 Outside heat exchanger 19, 20, 24 Check valve 21 Refrigerant tank 22 Expansion valve 30 Control device 31 Blow-off mode switch 32 Operation mode switch 33 Suction wind temperature sensor for indoor heat exchanger for heat absorption 34 Blow-out temperature sensor for indoor heat exchanger for heat absorption 35 Room temperature sensor 37 for blow-off temperature of indoor heat exchanger for heat dissipation Outside air temperature sensor 38 Room temperature setting device 39 Fan switch eTO Temperature deviation amount TO Target outlet temperature TOmax Target outlet temperature upper limit Tsc Outlet air temperature

Claims (4)

[Claims] A refrigerant is circulated to an outdoor heat exchanger (18) and an indoor heat exchanger by driving a compressor (16), and the indoor heat exchanger is connected to a suction side of the compressor. (14) and switching valve (17)
Thus, in an air conditioner comprising an outdoor heat exchanger during cooling, and an indoor heat exchanger (15) for heat dissipation connected to the discharge side of the compressor without passing through the outdoor heat exchanger during heating, the target blowout is performed during heating. The compressor control device for an air conditioner, wherein the compressor is driven at an operating frequency based on a difference between a temperature and an actual blown air temperature of the indoor heat exchanger for heat radiation. 2. The compressor control device for an air conditioner according to claim 1, wherein said operating frequency is calculated as a proportional value of a difference between a target outlet air temperature and an actual outlet air temperature. 3. The compressor according to claim 2, wherein the operating frequency is calculated by adding an integral increase / decrease value of a difference between a target outlet temperature and an actual outlet air temperature to the proportional value. Control device. 4. The indoor heat exchangers (14, 15) are provided with a fan (12) and a fan switch (39) capable of selecting a rotation speed of the fan in a plurality of stages. The compressor control device for an air conditioner according to claim 1, wherein an upper limit is set to the target outlet temperature when a predetermined rotation speed on the side is selected.