JPH07144530A - Air conditioner for electric automobile - Google Patents

Abstract

PURPOSE:To perform compressor control corresponding to the travel state of a vehicle or the change of environmental conditions. CONSTITUTION:The refrigerant compressor of a refrigerating cycle is driven by a separate electric motor 24 from a travel motor for a vehicle, and the rotating speed of this electric motor 24 is variable according to the frequency characteristic of an inverter 26. An air-conditioning control device 5 performs air-conditioning control on the basis of each switch operation at an air- conditioning control panel 31. Upon receiving a signal for turning off the travel motor, this air-conditioning control device 5 outputs a control signal to the inverter 26 so as to change the frequency characteristic of the inverter 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for an electric vehicle having a refrigerant compressor driven by an electric motor.

[0002]

2. Description of the Related Art Conventionally, in air conditioners for electric vehicles,
The refrigerant compressor is driven by an electric motor for driving the compressor, which is provided separately from the vehicle drive motor, and the refrigerant discharge amount of the refrigerant compressor is determined according to the rotation speed of the electric motor. Further, the rotation speed of the electric motor is determined by the frequency (see FIG. 4) of the inverter output corresponding to the position of the temperature control lever provided on the air conditioner operation panel. That is, the rotation speed of the refrigerant compressor, that is, the refrigerant discharge amount is determined according to the position of the temperature adjusting lever set by the occupant.

[0003]

However, in the conventional air conditioner for an electric vehicle, since the frequency characteristic of the inverter that determines the rotation speed of the electric motor is single, a change in the running state of the vehicle, environmental conditions, etc. Compressor control corresponding to is not possible. For example, even when the vehicle is stopped, that is, when the vehicle drive motor is off, the temperature adjustment lever is set to MAX.
When the refrigerant compressor is driven in the (maximum heating or maximum cooling) position, the vehicle is traveling (that is, the traveling motor is ON).
Since noise and vibration associated with the operation of the refrigerant compressor are relatively large as compared with the above case, the passenger is uncomfortable.

Further, during the cooling operation, the cooling load is larger when there is solar radiation than when there is no solar radiation. Therefore, in order to maintain the same vehicle interior temperature, when there is no solar radiation when there is solar radiation. It is necessary to increase the cooling capacity.
However, if the inverter has a single frequency characteristic as described above, the cooling capacity is uniquely determined according to the setting position of the temperature control lever. Insolation cannot be corrected. The present invention has been made in view of the above circumstances, and an object thereof is to provide an air conditioner for an electric vehicle capable of controlling a compressor in response to changes in the running state of the vehicle or environmental conditions.

[0005]

In order to achieve the above-mentioned object, the present invention comprises a duct for introducing blown air into the passenger compartment, a blower for introducing air into the duct and sending the air into the passenger compartment, and an electric motor. Refrigeration provided with a refrigerant compressor that compresses and discharges the drawn refrigerant, and an indoor heat exchanger that performs heat exchange between the refrigerant supplied by the operation of the refrigerant compressor and the air flowing in the duct. The present invention provides a cycle, an inverter that controls the rotation speed of the electric motor according to frequency characteristics, and a frequency characteristic changing unit that changes the frequency characteristics of the inverter when a prespecified signal is input. As a means.

[0006]

In the electric vehicle air conditioner of the present invention having the above structure, the rotation speed of the electric motor for driving the refrigerant compressor is
It is controlled according to the frequency characteristics of the inverter. The frequency characteristic of the inverter is changed by the frequency characteristic changing means when a signal specified in advance is input. Therefore, in the electric motor, when a pre-specified signal is input to the frequency characteristic changing means, the frequency characteristic of the inverter up to that time (before the signal is input) is changed to the frequency characteristic changed by the frequency characteristic changing means. Rotational speed control is performed accordingly.

[0007]

EXAMPLES Next, the first example of the air conditioner for an electric vehicle of the present invention
An embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a blowing system of an air conditioner 1 for an electric vehicle. The air conditioner 1 for an electric vehicle of this embodiment includes a duct 2 for introducing air into the vehicle interior, a blower 3 for introducing air into the duct 2 and sending the air into the vehicle interior, and a heat pump type refrigeration cycle 4 (Fig. 2), and an air conditioner control device 5 (see FIG. 3).

The duct 2 has a branch duct 2a at its downstream end.
2d are connected, and the tip ends of the respective branch ducts 2a to 2d are communicated with the air outlets 6 to 9 that open into the vehicle interior.
The outlets 6 to 9 are a defroster outlet 6 that blows air toward the window glass of the vehicle, a face outlet 7 that blows air toward the upper body (head and chest) of the occupant, and a side that blows air from both sides in the passenger compartment. It comprises a face air outlet 8 and a foot air outlet 9 that blows air toward the feet of the occupant. The defroster outlet 6, the face outlet 7, and the foot outlet 9 are selectively opened and closed by outlet switching dampers 10 to 12, respectively. Also, the side face outlet 8
The side face outlet 8 is manually operated by the passenger.
An opening / closing damper 13 for opening and closing is provided.

The blower 3 comprises a blower case 3a, a centrifugal fan 3b, and a blower motor 3c. The rotation speed of the blower motor 3c is determined according to the voltage applied to the blower motor 3c via the motor drive circuit 14 (see FIG. 3). To be done. The blower case 3a is formed with an inside air introduction port 15 for introducing the cabin air (inside air) and an outside air introduction port 16 for introducing the cabin outside air (outside air), and the inside air introduction port 15
An inside / outside air switching damper 17 that selectively opens and closes the outside air inlet 16 and the outside air inlet 16 is provided.

As shown in FIG. 2, the heat pump type refrigeration cycle 4 includes a refrigerant compressor 18, an indoor heat exchanger 19, an outdoor heat exchanger 20, a first pressure reducing device 21, a second pressure reducing device 22,
It is composed of an accumulator 23 and a flow path switching means (described later). The refrigerant compressor 18 is driven by an electric motor 24 different from a traveling motor (not shown) to compress and discharge the sucked refrigerant, and the refrigerant discharge is performed according to the rotation speed of the electric motor 24. The amount changes. The electric motor 24, together with the refrigerant compressor 18, has an airtight container 25.
Inverter 26 (see FIG. 3)
The rotation speed is changed according to the frequency characteristic (see FIG. 4).

The indoor heat exchanger 19 is arranged in the duct 2 and exchanges heat between the refrigerant supplied by the operation of the refrigerant compressor 18 and the air passing through the indoor heat exchanger 19. It sometimes functions as a refrigerant condenser, and also functions as a refrigerant evaporator during cooling operation. Outdoor heat exchanger 20
Is arranged outside the vehicle compartment and exchanges heat between the refrigerant supplied by the operation of the refrigerant compressor 18 and the blown air (outside air) by the outdoor fan 27, and functions as a refrigerant evaporator during heating operation, It functions as a refrigerant condenser during operation.

The first decompression device 21 decompresses and expands the refrigerant supplied to the indoor heat exchanger 19 during the cooling operation, and uses a fixed-throttle capillary tube. The second decompression device 22 decompresses and expands the refrigerant supplied to the outdoor heat exchanger 20 during the heating operation, and uses a fixed-throttle capillary tube like the first decompression device 21. The accumulator 23 separates the refrigerant flowing back to the refrigerant compressor 18 into gas-liquid separation to store the liquid refrigerant, and sends only the gas-phase refrigerant to the refrigerant compressor 18.

The flow path switching means switches the flow direction of the refrigerant between the heating operation and the cooling operation. The four-way valve 28,
It is composed of a first check valve 29 and a second check valve 30. This flow path switching means switches the flow direction of the refrigerant between the heating operation and the cooling operation as follows.

During the heating operation, the refrigerant discharged from the refrigerant compressor 18 is a four-way valve 28 → indoor heat exchanger 19 → first check valve 29 → second pressure reducing device 22 → outdoor heat exchanger 20 → accumulator 23. → The refrigerant is switched to flow in the order of the compressor 18 (the flow of the refrigerant during the heating operation is indicated by a solid arrow H in the figure). During the cooling operation, the refrigerant discharged from the refrigerant compressor 18 is the four-way valve 28 → the outdoor heat exchanger 20 → the second check valve 30.
-> 1st decompression device 21-> indoor heat exchanger 19-> accumulator 23-> It changes so that it may flow in order of the refrigerant compressor 18 (the flow of the refrigerant at the time of air_conditioning operation is shown by the broken line arrow C in a figure).

The air conditioner control device 5 has a built-in microcomputer, and as shown in FIG. 3, each damper (air outlet switching damper 10) is operated based on each switch operation on the air conditioner operation panel 31 (see FIG. 6). ˜12, servo motors 32 and 33 for driving the inside / outside air switching damper 17), the motor drive circuit 14, the inverter 26, the four-way valve 28, and a control signal are output to the fan motor 27a of the outdoor fan 27.

Further, the air conditioner control device 5 variably controls the frequency characteristic of the inverter 26 by the output signal of the traveling inverter 34 (see FIG. 3) for controlling the rotation speed of the traveling motor (variable frequency characteristic of the present invention). means). Specifically, when a signal for turning off (stopping) the traveling motor is input from the traveling inverter 34, a control signal for changing the frequency characteristic of the inverter 26 from the characteristic shown in FIG. Output to.

The inverter 2 shown in FIGS. 4 and 5 is used.
The frequency characteristic 6 indicates the frequency corresponding to the setting position of the temperature adjusting lever 35 (see FIG. 6) provided on the air conditioner operation panel 31. That is, in the frequency characteristic shown in FIG. 4, a frequency of 20 (Hz) is output when the temperature adjusting lever 35 is at MIN (left end position in FIG. 6), and when the temperature adjusting lever 35 is at MAX (right end position in FIG. 6). 120
A frequency of (Hz) is output and changes linearly between MIN and MAX. On the other hand, the frequency characteristic shown in FIG. 5 is the same as the frequency characteristic shown in FIG. 4 from the MIN to the point A in the figure, but from the point A in the figure to MAX, the frequency characteristic is shown in FIG. Is set to 80 (HZ).

The air conditioner operation panel 31 is arranged on an instrument panel (not shown) in the passenger compartment, and in addition to the temperature control lever 35 described above, as shown in FIG. 6, a blower outlet for setting a blower outlet mode. A mode switch 36, an inside / outside air mode switch 37 for setting the inside / outside air mode, an air volume setting switch 38 for setting the air volume level of the blower 3, and an operation mode switch 39 for switching the operation mode are provided.

Next, the operation of this embodiment will be described. A) When the heating mode is selected The high-temperature high-pressure refrigerant compressed by the refrigerant compressor 18 passes through the four-way valve 28 and is sent to the indoor heat exchanger 19, as shown by the solid arrow in FIG. The indoor heat exchanger 19 exchanges heat with the air in the duct 2 to condense and liquefy. Indoor heat exchanger 1
The refrigerant flowing out of 9 passes through the first check valve 29,
It is decompressed by the second decompression device 22 and supplied to the outdoor heat exchanger 20, where it is heat-exchanged with the outside air and evaporated. The refrigerant evaporated in the outdoor heat exchanger 20 is a four-way valve 28.
And the refrigerant compressor 18 again through the accumulator 23.
Is sucked into. As a result, the air that has been overheated by heat exchange with the high-temperature and high-pressure refrigerant in the indoor heat exchanger 19 is sent into the vehicle interior, thereby heating the vehicle interior.

(B) When the cooling mode is selected The high-temperature high-pressure refrigerant compressed by the refrigerant compressor 18 is sent to the outdoor heat exchanger 20 through the four-way valve 28, as shown by the broken line arrow in FIG. The heat is exchanged with the outside air in the outdoor heat exchanger 20 to be condensed and liquefied. The refrigerant flowing out of the outdoor heat exchanger 20 passes through the second check valve 30, is depressurized by the first pressure reducing device 21, and is supplied to the indoor heat exchanger 19. Evaporate by exchanging heat with the air. The refrigerant evaporated in the indoor heat exchanger 19 is a four-way valve 28.
And the refrigerant compressor 18 again through the accumulator 23.
Is sucked into. As a result, the air cooled by heat exchange with the low-temperature low-pressure refrigerant in the indoor heat exchanger 19 is sent into the vehicle interior, thereby cooling the vehicle interior.

In the above operation, the heating capacity and the cooling capacity of the indoor heat exchanger 19 are determined by the refrigerant compressor 18 respectively.
The temperature adjustment lever 35 adjusts the rotation speed (refrigerant discharge amount), that is, the frequency of the inverter 26 that determines the rotation speed of the electric motor 24. Here, the frequency of the inverter 26 is set such that the vehicle is running (running motor: O
If it is N), it is determined based on the frequency characteristic shown in FIG. 4. However, when the vehicle is stopped (traveling motor: OFF), the frequency of the inverter 26 is controlled by the control signal output from the air conditioner control device 5. Since the characteristics are changed,
It will be determined based on the frequency characteristics shown in.

Therefore, when the vehicle is at a stop, the frequency of the inverter 26 is limited to 80 (Hz) even if the temperature adjusting lever 35 is on the MAX side from the point A (see FIG. 5). The number of rotations of 18 does not exceed a certain number of rotations. Therefore, even if the temperature adjusting lever 35 is set to the MAX position, the rotation speed of the refrigerant compressor 18 is suppressed to be lower than that when the vehicle is traveling.
Noise and vibration associated with the operation of No. 8 are reduced, and discomfort given to an occupant can be reduced. It should be noted that when the vehicle is traveling, noise and vibration associated with the operation of the refrigerant compressor 18 are relatively small as compared with when the vehicle is stopped, and this is not a problem that causes an occupant to feel discomfort. , And the temperature control characteristics are emphasized, and the refrigerant compressor 18 is operated based on the frequency characteristics shown in FIG.

In this embodiment, the frequency characteristic of the inverter 26 when the vehicle is stopped is shown in FIG. 5. However, it is not necessary to limit the frequency characteristic to that shown in FIG. 5, and as shown in FIG. Frequency of the temperature control lever 35
8 may be gradually suppressed from the MIN position, or, as shown in FIG. 8, the characteristic may be gradually suppressed from the middle. Further, in the present embodiment, an example in which the frequency characteristic of the inverter 26 is linearly changed by the temperature adjusting lever 35 is shown, but as shown in FIG. 9, the frequency characteristic of the inverter 26 during vehicle traveling is changed stepwise. May be. Therefore, the frequency characteristic when the vehicle is stopped may be changed stepwise as shown in FIGS.

Next, a second embodiment of the present invention will be described. In this embodiment, as shown in FIG. 13, an air conditioner operation panel 31 is provided with a power saving switch 40. When the power saving switch 40 is in the ON state, the frequency characteristic of the inverter 26 is changed via the air conditioner control device 5. Be changed. The power-saving switch 40 switches between an ON state and an OFF state each time it is operated (pressed). When the power-saving switch 40 is in the OFF state, the electric motor 24 is driven based on the frequency characteristic shown in FIG. 4 (or FIG. 9). When the power saving switch 40 is in the ON state by controlling the rotation speed of (the number of rotations of the refrigerant compressor 18),
The rotation speed of the electric motor 24 is controlled based on the frequency characteristics shown in FIG. 5 (or FIG. 7, FIG. 8, FIG. 10 to FIG. 12).

As a result, when the power saving switch 40 is turned on, for example, in FIG. 5, the frequency of the inverter 26 is 80 when the temperature adjusting lever 35 is on the MAX side from the point A.
Since the rotation speed of the refrigerant compressor 18 is suppressed by being limited to (Hz), the consumption of the refrigerant compressor 18 is increased as compared with the case where the rotation speed of the electric motor 24 is controlled based on the frequency characteristic shown in FIG. The power can be reduced. In order to increase the power saving effect, the control of this embodiment may be used in combination with other power saving control (for example, the rotation speed control of the outdoor fan 27).

Next, a third embodiment of the present invention will be described. In this embodiment, a solar radiation sensor (not shown) is provided to change the frequency characteristic of the inverter 26 according to the presence or absence of solar radiation in the cooling mode. If there is solar radiation during cooling operation, the cooling load will be greater than if there is no solar radiation,
It is necessary to increase the cooling capacity. Therefore, when the solar radiation is detected by the solar radiation sensor in the state where the cooling mode is set, the frequency characteristics shown in FIG.
4 (or FIGS. 15 to 18). As a result, when there is solar radiation, the cooling capacity can be increased by operating the refrigerant compressor 18 at a higher rotation speed than usual.

[0027]

The air conditioner for an electric vehicle according to the present invention is a compressor that responds to changes in the running state or environmental conditions of the vehicle by varying the frequency characteristics of the inverter when a prespecified signal is input. Control can be performed. For example, by varying the frequency characteristic of the inverter so that the number of rotations of the refrigerant compressor is reduced when the vehicle is stopped, noise and vibration associated with the operation of the refrigerant compressor are relatively increased compared to when the vehicle is running. Since the size can be reduced, it is possible to reduce the discomfort felt by an occupant due to noise and vibration accompanying the operation of the refrigerant compressor.

When the power saving switch provided on the air conditioner operation panel is in the ON state, the frequency characteristic of the inverter is changed so as to reduce the rotation speed of the refrigerant compressor, so that the power saving switch is in the OFF state (normal use). It is possible to reduce the power consumption of the refrigerant compressor as compared with the state).

Further, when the solar radiation is present in the cooling mode, the frequency characteristic of the inverter is changed so that the refrigerant compressor is operated at a high rotation speed, so that the cooling capacity is enhanced as compared with the case without the solar radiation. You can As a result, it is possible to suppress an increase in vehicle interior temperature due to the effects of solar radiation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a blowing system of an air conditioner for an electric vehicle.

FIG. 2 is a refrigeration cycle diagram according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a control system according to the first embodiment.

FIG. 4 is a diagram showing an inverter frequency characteristic when the vehicle is traveling.

FIG. 5 is a diagram showing inverter frequency characteristics when the vehicle is stopped or when power is saved.

FIG. 6 is a plan view of an air conditioner operation panel.

FIG. 7 is a diagram showing a modification of the inverter frequency characteristic when the vehicle is stopped or when power is saved.

FIG. 8 is a diagram showing a modification of the inverter frequency characteristic when the vehicle is stopped or when power is saved.

FIG. 9 is a diagram showing a modification of the inverter frequency characteristic when the vehicle is traveling.

FIG. 10 is a diagram showing a modified example of the inverter frequency characteristic when the vehicle is stopped or when power is saved.

FIG. 11 is a diagram showing a modified example of the inverter frequency characteristic when the vehicle is stopped or when power is saved.

FIG. 12 is a diagram showing a modified example of the inverter frequency characteristic when the vehicle is stopped or when power is saved.

FIG. 13 is a plan view of an air conditioner operation panel according to a second embodiment.

FIG. 14 is a diagram showing an inverter frequency characteristic (during solar radiation) according to the third embodiment.

FIG. 15 is a diagram showing a modification of inverter frequency characteristics (during solar radiation).

FIG. 16 is a diagram showing a modification of inverter frequency characteristics (during solar radiation).

FIG. 17 is a diagram showing a modification of inverter frequency characteristics (during solar radiation).

FIG. 18 is a diagram showing a modification of inverter frequency characteristics (during solar radiation).

[Explanation of symbols]

 1 Air Conditioner for Electric Vehicle 2 Duct 3 Blower 4 Refrigeration Cycle 5 Air Conditioner Control Device (Frequency Characteristic Variable Means) 18 Refrigerant Compressor 19 Indoor Heat Exchanger 24 Electric Motor 26 Inverter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nao Sugasawa 1-1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. A duct for introducing blown air into the vehicle compartment; b) a blower for introducing air into the duct to feed the air into the vehicle compartment; and c) being driven by an electric motor to compress suctioned refrigerant. A refrigerating cycle including a refrigerant compressor that discharges the refrigerant, and an indoor heat exchanger that exchanges heat between the refrigerant supplied by the operation of the refrigerant compressor and the air flowing in the duct; and d) rotation of the electric motor. An air conditioner for an electric vehicle, comprising: an inverter that controls speed according to frequency characteristics; and e) frequency characteristic changing means that changes frequency characteristics of the inverter when a prespecified signal is input.