JPH07237431A - Method to control air conditioner for electric automobile - Google Patents

Abstract

PURPOSE:To provide a method to control an air conditioner for an electric automobile, which prevents the blowing-out air quantity and blowout temperature from lowering caused by the ventilation resistance and heat loss in an auxiliary heater. CONSTITUTION:When an auxiliary heater 9 stops, an air mix damper 10 is turned to close a passage 7 so that air may not flow into the passage 7 in which an auxiliary heater 9 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an air conditioner for an electric vehicle,
In particular, it relates to a control method for an air conditioner for an electric vehicle having an auxiliary heater.

[0002]

2. Description of the Related Art Conventionally, as an air conditioner for an electric vehicle,
For example, there is a heat pump type electric vehicle air conditioner described in Japanese Utility Model Publication No. 4-1011. That is, on the downstream side of the indoor heat exchanger arranged in the air conditioning unit, a cooling passage and a heating passage are arranged in parallel, and an auxiliary heater is arranged in the heating passage, and each of the cooling passage and the heating passage is arranged. By opening and closing the upstream side of the above with a switching door during cooling and heating operation, ventilation is provided to a predetermined passage during cooling and heating operation.

[0003]

However, in the above-mentioned air conditioner for an electric vehicle, during the heating operation, air constantly flows through the heating passage in which the auxiliary heater is arranged. For this reason, for example, when the temperature of the outside air is not too low, the heating pump alone heats the air, and the air flows through the heating passage even when the auxiliary heater is not used. As a result,
There is a problem that the ventilation resistance of the auxiliary heater not only lowers the amount of blown air but also removes heat when the air passes through the inside of the auxiliary heater, thus lowering the blowing temperature.

In view of the above problems, it is an object of the present invention to provide a method of controlling an air conditioner for an electric vehicle, which can prevent ventilation resistance based on an auxiliary heater, and reduction of blowing air amount and blowing temperature due to heat loss.

[0005]

In order to achieve the above object, a control method for an air conditioner for an electric vehicle according to the present invention,
An in-vehicle heat exchanger arranged in the air conditioning unit, an air mix damper provided downstream of the in-vehicle heat exchanger to divide into two flow paths, and an auxiliary heater provided in one flow path. In an air conditioner for an electric vehicle, which comprises a control means for controlling the rotation of the air mix damper, the air mix damper is rotated so that air does not flow through a flow path provided with the auxiliary heater when the auxiliary heater is stopped. There is a way to do it. Further, in the above-described method for controlling an air conditioner for an electric vehicle, the auxiliary heater may be stopped when the temperature of the outside air exceeds a predetermined temperature, and may be heated only by the heat pump. In this embodiment, 5 ° C. is set as the predetermined temperature. Further, when the driving frequency of the compressor that constitutes the heat pump including the in-vehicle heat exchanger is not the maximum frequency, only the heat pump may be driven and the auxiliary heater may be stopped to heat.

[0006]

Therefore, according to the present invention, for example, when the temperature of the outside air is not so low and heating is performed only by the heat pump, the air does not flow through the flow path provided with the auxiliary heater.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to the accompanying drawings shown in FIGS. As shown in FIG. 1, an air conditioner for an electric vehicle according to the present embodiment is provided with an intake damper 2 for switching inside / outside air on the upstream side in an air conditioning unit 1.
Is provided to selectively suck outside air or inside air into the unit 1. The suction of air into the unit 1 is performed by rotating a blower 4 provided on the downstream side of the intake damper 2 by a motor 3 connected to a control device 20 described later.

An in-vehicle heat exchanger 5 which constitutes a heat pump is arranged downstream of the blower 4. The temperature in the vicinity of the in-vehicle heat exchanger 5 is detected by the temperature sensor 6 provided in the vicinity of the downstream thereof, and the detection signal is input to the control device 20 described later.

On the downstream side of the in-vehicle heat exchanger 5, an air mix damper 10 is formed which divides the flow to form two flow paths 7 and 8.
Is provided, and the PTC is provided as an auxiliary heater in one of the flow paths 7.
A heater 9 is provided. The PTC heater 9 is a constant temperature heating element in which the resistance rapidly increases from a certain temperature and the temperature is kept constant by the current limiting action in the rapid resistance change region.

Further, at the outlet of the flow path 7, P
A damper 12 that adjusts the amount of air blown again by the TC heater 9 is provided. When the air mix damper 10 is rotated by the actuator 11 that operates based on the control signal from the control device 20,
In conjunction with this, the adjustment damper 12 causes the control device 20 to
It is rotated by the actuator 13 that operates based on the control signal.

A temperature sensor 1 is provided downstream of the flow paths 7 and 8.
4 is provided, and further, dampers 15, 16, 17 that are rotated by an actuator (not shown) are provided on the downstream side of the damper 4, so that air outlets into the vehicle are switched.

The control device 20 calculates based on various conditions input from the outside air sensor 21, the inside air sensor 22 and the temperature sensors 6 and 14 so that the air blowing temperature and air blowing amount are such that an occupant feels comfortable. In addition to the control, the dampers 15, 16 and 17 are rotated in accordance with the desired blowout mode selected by the mode changeover switch 23 to control the air blowout port.

Therefore, the air sucked by the rotation of the blower 4 and warmed by the in-vehicle heat exchanger 5 is diverted by the air mix damper 10, and one of the diverted air flows through the flow path 8 to the downstream side. To the other side, and the other to P
After flowing into the flow path 7 provided with the TC heater 9 to be warmed again, it is blown to the downstream side through the damper 12. In this way, the air blown to the downstream side is mixed, adjusted to a desired temperature, and then blown into the vehicle from a desired position by the dampers 15, 16 and 17. The temperature of the mixed air is detected by the temperature sensor 14 provided on the downstream side of the flow paths 7 and 8, and the detection signal is input to the control device 20.

Next, a method of controlling the air conditioner having the above-mentioned structure will be described with reference to the flow chart shown in FIG. First, the heating switch is turned on in step S1, and the heating operation is started in step S2. This heating operation involves inputting various conditions inside and outside the vehicle (inside air temperature, outside air temperature, solar radiation amount,
Adjust the air flow rate and air temperature based on the set temperature).

Then, in step S3, it is determined whether the outside air temperature exceeds a predetermined temperature. The predetermined temperature is
This is the lower limit value of the outside air temperature condition in which the vehicle interior can be brought to a desired temperature only by heating with a heat pump. In this embodiment, this is set to 5 ° C. When it is determined that the outside air temperature exceeds the predetermined temperature, the auxiliary heater 9 is stopped in step S4, and control is performed so that air does not flow into the flow path 7 provided with the auxiliary heater 9 in step S5. The air mix damper 10 is rotated by the actuator 11 that operates based on the control signal of the device 20 to close the flow path 7,
Continue driving.

Next, when it is determined in step S3 that the outside air temperature does not exceed the predetermined temperature, it is determined in step S6 whether the outside air temperature is equal to or higher than a specific temperature, and the temperature is equal to or higher than the specific temperature. If determined, the auxiliary heater 9 is operated at the Low level in step S7, and the operation is continued. The specific temperature is the lower limit value of the outside air temperature condition that can bring the interior of the vehicle to a desired temperature by heating with the Low level of the heat pump and the auxiliary heater. In the present embodiment, this is set to 0
℃.

Subsequently, when it is determined in step S6 that the outside air temperature is lower than a specific temperature, step S8
Then, the auxiliary heater 9 is operated at a high level to continue the operation.

According to the above-mentioned control method, when the outside air temperature is lower than the predetermined temperature of 5 ° C., the air conditioner having the above-mentioned structure is heated only by the heat pump, and the average room temperature does not reach the desired temperature. There was a shortage (see Figure 3).
On the other hand, when the outside air temperature was 5 ° C. or higher, which was the predetermined temperature, when the heating was performed only by the heat pump, the comfortable average room temperature was reached within the desired time (see FIG. 4).

Further, when the heat pump is driven and the auxiliary heater is operated at the Low level when the outside air temperature is in the range of 0 ° C. which is a specific temperature or more and less than 5 ° C. which is a predetermined temperature, a desired average is obtained. Room temperature was reached (see Figure 5). However, when the heat pump was driven under the same conditions as described above and the auxiliary heater was operated at the high level, the temperature averaged above the desired average room temperature, and heating was excessive (FIG. 6).

3 to 6, the blowout temperature means the temperature measured by the temperature sensor 14 arranged on the downstream side of the flow paths 7 and 8.

From the above experimental results, it was found that when the outside air exceeds a predetermined temperature, it can be heated only by the heat pump. However, in this case, since the air mix damper 10 closes the flow path 7 in which the auxiliary heater 9 is arranged, air does not flow into the flow path 7. Then, when the outside air temperature is equal to or higher than a specific temperature and lower than the predetermined temperature,
It suffices to drive the heat pump and operate the auxiliary heater at a low level, and further, if the outside air is below a specific temperature, drive the heat pump and operate the auxiliary heater at a high level. I understood.

Next, another control method focusing on the temperature difference between the set temperature and the room temperature and the driving frequency of the compressor will be described with reference to FIG.
Follow the instructions below. First, in step S10, it is determined whether or not the drive frequency of the compressor forming the heat pump is the maximum frequency, and when it is determined that the drive frequency is the maximum frequency,
In step S11, it is determined whether or not the temperature difference between the set temperature and the room temperature is equal to or more than a predetermined value. If it is determined that the temperature difference is equal to or more than the predetermined value, the auxiliary heater is set to High in step S12.
Operate at level and continue driving.

The predetermined value of the temperature difference means that the compressor of the heat pump is driven at the maximum driving frequency, and
This is a limit value that can raise the temperature in the vehicle interior to the set temperature when the auxiliary heater is operated at the Low level. In this embodiment, this is set to 10 ° C.

On the other hand, when it is determined in step S10 that the frequency is not the maximum frequency, the auxiliary heater 9 is stopped in step S13, and then the air mix damper 10 is rotated in step S14 to set the flow path in which the auxiliary heater 9 is provided. Closed 7,
Continue driving.

Further, when it is judged in step S11 that the temperature difference between the set temperature and the room temperature is not more than the predetermined value, the auxiliary heater 9 is operated at the Low level to continue the operation.

In the above embodiment, the auxiliary heater P
Although the case of using the TC heater has been described, the present invention is not limited to this, and a normal electric heater may be used,
Further, the auxiliary heater is not limited to the two-stage switching type, but a multi-stage switching type or a continuously changing type may be used. Furthermore, in the above-described embodiment, the case where the adjustment damper is provided at the outlet of the flow path provided with the auxiliary heater has been described, but the present invention is not limited to this, and the flow path may be closed only by the air mix damper. Good.

[0027]

As is apparent from the above description, according to the control method of the air conditioner for an electric vehicle of the present invention, the temperature of the air is not so low that the auxiliary heater is stopped and only the heat pump is used for heating. In this case, air does not flow into the flow path provided with the auxiliary heater. For this reason, there is no reduction in the amount of blown air due to the ventilation resistance of the auxiliary heater, and since the air is not deprived of heat by the auxiliary heater, the blowing temperature does not decrease.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an air conditioner for an electric / electric vehicle according to the present invention.

FIG. 2 is a flowchart showing a method of controlling the air conditioner for the electric vehicle shown in FIG.

FIG. 3 is a graph showing heating performance of the electric vehicle air conditioner shown in FIG. 1.

FIG. 4 is a graph showing the heating performance of the electric vehicle air conditioner shown in FIG. 1.

5 is a graph showing heating performance of the electric vehicle air conditioner shown in FIG. 1. FIG.

FIG. 6 is a graph showing heating performance of the electric vehicle air conditioner shown in FIG. 1.

FIG. 7 is a flowchart showing another control method of the electric vehicle air conditioner shown in FIG. 1.

[Explanation of symbols]

1 ... Heat unit, 4 ... Blower, 5 ... In-vehicle heat exchanger,
7, 8 ... Flow path, 9 ... PTC heater, 10 ... Air mix damper, 20 ... Control device.

Claims (3)

[Claims] 1. An in-vehicle heat exchanger arranged in an air conditioning unit and a downstream side of the in-vehicle heat exchanger, which is divided into two parts.
An air conditioner for an electric vehicle comprising an air mix damper forming one flow path, an auxiliary heater provided in one flow path, and a control means for controlling the rotation of the air mix damper, wherein the auxiliary heater is stopped. A method for controlling an air conditioner for an electric vehicle, characterized in that the air mix damper is rotated so that air does not flow through a flow path provided with an auxiliary heater. 2. The air conditioner for an electric vehicle according to claim 1, wherein only the heat pump is driven and the auxiliary heater is stopped to heat when the temperature of the outside air exceeds a predetermined temperature. Control method. 3. When the frequency of the compressor constituting the heat pump including the in-vehicle heat exchanger is not the maximum frequency,
The method for controlling an air conditioner for an electric vehicle according to claim 1, wherein only the heat pump is driven and the auxiliary heater is stopped to heat the air.