JP3356359B2 - Electric vehicle air conditioner - Google Patents

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, and more particularly to an air conditioner for an electric vehicle capable of appropriately performing air conditioning with a heat exchanger inside the vehicle in response to a change in load acting on a compressor. It is about.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner for an electric vehicle, FIG.
As shown in (1), the inside and outside of the vehicle is cooled and heated using a heat pump cycle including a compressor 1, a four-way valve 2, a vehicle-side heat exchanger 3, a vehicle-side heat exchanger 4, an expansion valve 5, and the like.

That is, in this heat pump cycle, in the heating mode, the four-way valve 2 is switched as shown by a solid line in the figure and the compressor 1 is driven to change the heat exchange medium as shown by the solid line arrow in the figure. Circulating in the order of the heat exchanger 3, the heat exchanger 3, the expansion valve 5, and the heat exchanger 4,
The air passing through the inside heat exchanger 3 is heated to supply warm air to the inside of the vehicle.

In the cooling mode, the four-way valve 2 is switched as shown by the dotted line in the figure, and the compressor 1 is driven, so that the heat exchange medium is changed to the outside heat exchanger 4 as shown by the dotted arrow in the figure. Then, the air is circulated in the order of the expansion valve 5 and the vehicle interior heat exchanger 3 to cool the air passing through the vehicle interior heat exchanger 3 and supply cool air to the vehicle interior.

[0005] If the compressor 1 is abnormally heated due to an increase in the load acting on the compressor 1, a failure may occur. Therefore, a protection device is provided for stopping the drive of the compressor 1 when the discharge temperature of the compressor 1 rises above a predetermined value before the compressor 1 fails.

[0006]

However, in the conventional air conditioner for an electric vehicle, the compressor 1 is stopped by the protection device every time the load fluctuates, for example, when the vehicle is congested during cooling in the vehicle. , Heat exchanger 3 inside the car
Therefore, a desired heating state or cooling state cannot be obtained, and as a result, the temperature of the air blown into the vehicle becomes unstable, resulting in a problem that appropriate air conditioning cannot be performed.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an air conditioner for an electric vehicle which can perform appropriate air conditioning with a heat exchanger inside a vehicle regardless of a load acting on a compressor. And

[0008]

In order to achieve the above-mentioned object, according to the present invention, a compressor is driven to circulate a heat exchange medium in a heat pump cycle, and heat or cools air passing through a heat exchanger inside the vehicle. Thus, in an electric vehicle air conditioner configured to supply warm air or cool air to the inside of a vehicle, a flow adjusting device that is disposed in the middle of the heat pump cycle and adjusts a flow rate of a heat exchange medium passing therethrough; A temperature sensor for detecting an abnormality-related temperature, and a predetermined target flow rate until the abnormality-related temperature detected by the temperature sensor exceeds a predetermined threshold value; And a flow control means for controlling the flow rate.

The temperature sensor may detect a temperature of the heat exchange medium immediately after being discharged from the compressor, or may detect a temperature near the motor of the compressor. The former has an advantage that the temperature of the entire compressor can be easily grasped, and the latter has an advantage that the temperature at a point where the compressor is most likely to fail can be directly detected.

Further, the electric vehicle air conditioner is provided with frequency detecting means for detecting a driving frequency of the compressor, and the flow rate controlling means calculates a target flow rate based on a frequency detected by the frequency detecting means. It is possible to drive and control the flow rate adjusting means according to the target flow rate and to drive the flow rate adjusting means at a predetermined target flow rate larger than the target flow rate if the temperature detected by the temperature sensor exceeds a predetermined threshold value. It is.

Further, the air conditioner for an electric vehicle is provided with an in-vehicle heat exchange temperature sensor for detecting a temperature near the downstream of the in-vehicle heat exchanger, and the flow rate control means detects the temperature detected by the in-vehicle heat exchange temperature sensor. Calculating a target flow rate based on the target flow rate, controlling the flow rate adjusting means in accordance with the target flow rate, and if the temperature detected by the temperature sensor exceeds a predetermined threshold value, the flow rate at a predetermined target flow rate larger than the target flow rate. It is also possible to drive the adjusting means.

Further, the air conditioner for an electric vehicle is provided with frequency detecting means for detecting a driving frequency of the compressor, and an in-vehicle heat exchange temperature sensor for detecting a temperature near a downstream of the in-vehicle heat exchanger. The flow rate control means calculates a target flow rate based on the detection frequency of the frequency detection means and the temperature detected by the in-vehicle heat exchange temperature sensor, and drives and controls the flow rate adjustment means in accordance with the target flow rate, and the temperature sensor If the detected temperature in step (1) exceeds a predetermined threshold value, the flow rate adjusting means can be driven at a predetermined target flow rate that is larger than the target flow rate.

[0013]

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

In the electric vehicle air conditioner shown in FIG. 1, the cycle in which the heat exchange medium circulates can be switched between a heating cycle and a cooling cycle by a four-way valve 10. During these cycles, a compressor 11, an inboard heat exchanger 12, an outboard heat exchanger 13, and an accumulator 14 are provided outside the four-way valve 10.

In addition, a pulse motor 15a is rotated by a predetermined number of steps in a pipe a between the inside heat exchanger 12 and the outside heat exchanger 13 based on a control signal from an air conditioner control device 27 described below. A flow control valve 15 is provided which can adjust the opening degree of the flow path, that is, the throttle value P by driving.

The four-way valve 10 has a structure in which a rotary body having a pair of communication passages is accommodated in a valve body. The four-way valve 10 is switched as shown by a solid line at the time of heating, and at the time of cooling, based on a control signal from a control device (not shown). It switches as shown by the dotted line.

As shown in FIG. 6, the compressor 11 has a motor 16 built in a main body 11a.
6, the heat exchange medium is sucked into the main body through the suction pipe 11b connected to the lower side surface, brought into a high temperature and high pressure state, and then discharged through the discharge pipe 11c. The drive frequency of the motor 16 is detected by a frequency detection sensor 17 (see FIG. 1). The discharge pipe 11c
Is provided with a temperature sensor 18 for detecting a heat exchange medium temperature T ₀ immediately after discharge from the compressor 11.

The inside heat exchanger 12 and the outside heat exchanger 13 have a structure in which flat tubes and corrugated fins are laminated and integrated. When the heat exchange medium flows meandering through the flat tubes, It can exchange heat with the air passing through the fins.

The in-vehicle heat exchanger 12 is disposed in the unit 19 at the front of the vehicle, and radiates heat during heating to warm the passing air and cools the air during cooling. On the other hand, the vehicle exterior heat exchanger 13 is attached to the front part of the vehicle, and exchanges heat between a heat exchange medium flowing inside the vehicle and outside air passing outside.

The accumulator 14 stores a heat exchange medium, separates gas and liquid, and supplies only gas to the compressor 11.

In the unit 19, in addition to the inside heat exchanger 12, a blower 20 located upstream of the inside heat exchanger 12 and a vehicle located near the outlet side of the inside heat exchanger 12 are provided. Inside heat exchange temperature sensor 21 and inside heat exchanger 12
, And an auxiliary heater 22 located downstream of. The downstream part of the unit 19 is a blowing direction switching unit 19a, in which a damper 23 is rotatably disposed, and
The air outlet 24a can be opened and closed, and other air outlets 24b and the like can be opened and closed by a damper (not shown). Each of the dampers rotates in conjunction with each other, and opens and closes predetermined outlets in accordance with an input signal from the outlet direction setting device 25.

The blower 20 includes a blower air volume setting device 2
In accordance with the set value input in 6, the rotation is performed so as to obtain a desired air volume. The input signal from the blower air volume setting device 26, the input signal from the blowing direction setting device 25, the temperature detected by the heat exchange temperature sensor 21 inside the vehicle, and the drive frequency of the compressor 11 detected by the frequency detection sensor 17 are controlled by an air conditioner control device. 27 are respectively input.

The air conditioner control device 27 controls the cooling / heating operation by issuing control signals to the compressor drive device 28, the auxiliary heater energization control device 29, and the blower air volume control device 30 based on these input signals. At this time, the flow control valve 15 is drive-controlled.

Hereinafter, the flow control valve 15 which is a feature of the present invention will be described.
Will be described with reference to the flowchart shown in FIG.

That is, in step S1, the in-vehicle heat exchange temperature sensor 21, the frequency detection sensor 17, and the temperature sensor 18
Etc., the temperature T near the downstream of the in-vehicle heat exchanger 12
_e , driving frequency F of compressor 11, compressor 1
The detection signals such as the temperature T _o of the heat exchange medium immediately after the discharge from No. 1 and the aperture value P of the flow control valve 15 are read.

In step S2, the target throttle value P 'of the flow control valve 15 is calculated by various methods, as will be described later, and in step S3, the heat exchange medium temperature T just after being discharged from the compressor 11 is calculated. It is determined whether or not _o exceeds the reference temperature T _o '. The reference temperature T _o ′ is a temperature at which an abnormality is likely to occur in the compressor 11.

If T _o > T _o ′, an excessive load acts on the compressor 11 when, for example, the vehicle becomes congested during cooling in the vehicle, and the compressor 11 is forced by a protection device (not shown). Is determined to be temporarily stopped. Therefore, in step S4, the target throttle value P 'is corrected upward to 1.3 * P' so that the flow rate of the heat exchange medium increases. Thus, the pressure of the heat exchange medium between the compressor 11 and the flow control valve 15 is reduced, and the compressor 11
Will be removed.

If T _o ≦ T _o ′, it is determined that the compressor 11 is operating normally, and the process proceeds to step S5 with the target aperture value P ′ obtained in step S2. I do.

In step S5, the flow control valve 15 is adjusted in accordance with the target throttle value P 'determined in step S2 or S4. In this case, the adjustment of the flow control valve 15
This is performed by increasing or decreasing the number of pulses of the pulse motor 15a to be driven.

The target throttle value P 'of the flow control valve 15 in step S2 can be determined, for example, by the following method.

[0031] 'unless a target aperture value P of the flow control valve 15' T _o> T _o in step S3 method of a constant. That is, in normal air conditioning, the throttle value P of the flow control valve 15 is kept constant, and the air conditioning capacity of the in-vehicle heat exchanger 12 is adjusted only by the driving frequency F of the compressor 11.

The downstream vicinity of the air temperature T _e of the interior heat exchanger 12, changing the method of determining the 'target aperture value P of the flow regulating valve 15 depending on whether it is less than' the reference temperature T _e is set in advance, respectively Air temperature T near the downstream of the heat exchanger 12 inside the vehicle
A method of calculating using _e and the driving frequency F of the compressor 11.

That is, in normal air conditioning, as shown in FIG. 3, it is first determined in step S10 whether or not T _e ≦ T _e ′ is satisfied.

If T _e ≦ T _e ′, the target aperture value P ′ is calculated in step S11 according to the following equation.

[0035]

(Equation 1)

In equation (1), K ₁ is a coefficient indicating the inclination of the straight line group on the left side in the graph of FIG. K ₂ (F) is a coefficient indicating which straight line is to be selected according to the drive frequency F of the compressor 11. According to this equation, if the vehicle interior-side heat exchange temperature T _e has been detected, taking into account the driving frequency F of the compressor 11, it is possible to calculate the target aperture value P '. In other words, it is possible to obtain a desired vehicle-side heat exchange temperature T _e, and without exerting excessive load on the compressor 1, it is possible to stably driven.

If T _e > T _e ′, step S1
In step 2, the target aperture value P 'is calculated according to the following equation.

[0038]

(Equation 2)

In equation (2), K ₃ is a coefficient indicating the slope of the straight line group on the right side in the graph of FIG. The control according to the heating or cooling state in the vessel 12 can be performed.

The reference temperature T _e ′ may be the air temperature immediately after passing through the in-vehicle heat exchanger 12 when the circulation direction of the heat exchange medium is switched in the heat pump cycle. That is, the flow rate of the heat exchange medium can be more appropriately changed by changing the calculation formula of the target throttle value P ′ of the flow control valve 15 in accordance with a change in the temperature control state (cooling or heating) in the heat exchanger 12 inside the vehicle. , And a favorable air-conditioning state can be obtained.

Only the driving frequency F of the compressor 11 is
Alternatively, the air temperature T _e near the downstream of the in-vehicle heat exchanger 12.
How to determine only by.

[0042] That is, the driving frequency F of the compressor 11 according to the graph shown in FIG. 5 or the target aperture value P of the flow control valve 15 'is gradually according to the downstream vicinity of the air temperature T _e of the interior side heat exchanger 12 is increased Is determined to be larger.

As in the above embodiment, the temperature sensor 1
8 is provided in the discharge pipe 11c,
1 may be provided in the motor 16 built in (shown by a two-dot chain line in FIG. 6). According to this, the temperature of the motor 16 that is most susceptible to the load acting on the compressor 11 is directly detected by the temperature sensor 18, and when the detected temperature exceeds a predetermined temperature, the drive control of the compressor 11 is controlled. Can do it.

[0044]

As is clear from the above description, according to the present invention, the flow regulating valve is provided in the middle of the heat pump cycle, and when the temperature related to the abnormality of the compressor exceeds a predetermined threshold value, the throttle value of the flow regulating valve is reduced. Is forcibly increased, so that there is no problem that the protection device operates and the compressor stops. Therefore, the inside air conditioning can always be appropriately performed.

In particular, according to the invention, the throttle value of the flow control valve is calculated based on the driving frequency of the compressor, the air temperature near the downstream side of the heat exchanger inside the vehicle, or both during normal air conditioning control. For example, even during normal air conditioning, control can be performed so as to be stable without increasing the load acting on the compressor.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an air conditioner for an electric vehicle according to an embodiment.

FIG. 2 is a flowchart showing drive control of a flow control valve in the air conditioner control device of FIG. 1;

FIG. 3 is a flowchart illustrating an example of calculation of a target aperture value in FIG. 2;

FIG. 4 is a graph showing a relationship between a temperature near a downstream side of a vehicle-side heat exchanger, a driving frequency of a compressor, and a throttle value of a flow control valve.

FIG. 5 shows the compressor drive frequency or the temperature near the downstream of the heat exchanger inside the vehicle and the throttle value of the flow control valve in the drive control of the flow control valve by the air conditioner control device of the air conditioner for an electric vehicle according to another embodiment. 6 is a graph showing the relationship of.

FIG. 6 is a partial sectional front view of the compressor.

FIG. 7 is a schematic diagram of an air conditioner for an electric vehicle according to a conventional example.

[Explanation of symbols]

 11 Compressor 15 Flow control valve (flow control means) 18 Temperature sensor 27 Air conditioner control device (air conditioner control means)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuki Maebobo 5658 Yoshikawa, Hachihonmatsu-cho, Higashihiroshima-shi, Hiroshima Prefecture Within Japan Climate Systems Co., Ltd. No. Japan Climate Systems Co., Ltd. (56) References JP-A-4-151318 (JP, A) JP-A-6-328933 (JP, A) JP-A-4-372422 (JP, A) JP-A-4 -240355 (JP, A) JP-A-7-266858 (JP, A) JP-A-62-178852 (JP, A) JP-A-63-290352 (JP, A) JP-A-3-98112 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60H 1/32 624 B60H 1/22 B60H 1/32 623 B60H 1/00 F25B 1/00 304 F25B 49/02 570 F25B 49/02 560

Claims (6)

(57) [Claims] 1. A warm air or a cool air is supplied to a vehicle interior by driving a compressor to circulate a heat exchange medium in a heat pump cycle and heating or cooling air passing through a vehicle interior heat exchanger. In the air conditioner for an electric vehicle, a flow rate adjusting means disposed in the middle of the heat pump cycle to adjust a flow rate of the heat exchange medium passing therethrough; a temperature sensor for detecting an abnormal temperature of the compressor; And a flow control means for driving the flow rate adjusting means by correcting the target flow rate upward if the abnormality-related temperature exceeds a predetermined threshold value. Automotive air conditioners. 2. The air conditioner for an electric vehicle according to claim 1, wherein the temperature sensor detects a temperature of the heat exchange medium immediately after being discharged from the compressor. 3. The air conditioner for an electric vehicle according to claim 1, wherein the temperature sensor detects a temperature near a motor of the compressor. 4. A frequency detecting means for detecting a driving frequency of the compressor, wherein the flow rate controlling means calculates a target flow rate based on a frequency detected by the frequency detecting means, and the flow rate adjusting means according to the target flow rate. 4. The method according to claim 1, further comprising: when the temperature detected by the temperature sensor exceeds a predetermined threshold value, drives the flow rate adjusting means by correcting the target flow rate upward. An air conditioner for an electric vehicle according to claim 1. 5. An in-vehicle heat exchange temperature sensor for detecting a temperature near the downstream of the in-vehicle heat exchanger, wherein the flow rate control means calculates a target flow rate based on the temperature detected by the in-vehicle heat exchange temperature sensor. Controlling the flow rate adjusting means in accordance with the target flow rate, and driving the flow rate adjusting means at a predetermined target flow rate larger than the target flow rate when the temperature detected by the temperature sensor exceeds a predetermined threshold value. The air conditioner for an electric vehicle according to any one of claims 1 to 3, wherein 6. A frequency detecting means for detecting a driving frequency of the compressor, and an in-vehicle heat exchange temperature sensor for detecting a temperature near a downstream of the in-vehicle heat exchanger, wherein the flow rate controlling means comprises a frequency detecting means. A target flow rate is calculated based on the detected frequency at the temperature and the temperature detected by the in-vehicle heat exchange temperature sensor. The air conditioner for an electric vehicle according to any one of claims 1 to 3, wherein the flow rate adjusting means is driven at a predetermined target flow rate larger than the first target flow rate when the flow rate exceeds the first target flow rate.