JP2002067660A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly heat inside a cabin even in a vehicle which is equipped with a high-efficiency diesel engine or the like. SOLUTION: When heating by a heater core 5 only is judged to be insufficient based on temperature of cooling water of an engine which is detected by a water temperature detection means 25 in the case of conducting heating operation by closing the third flow rate adjusting means 14, a clutch 8 is connected and a compressor 7 is driven. When the heating by the heater core 5 only is judged to be sufficient, the clutch 8 is cut off. In the heating or cooling operation, after the clutch 8 is cut off and the compressor 7 is stopped, when the clutch 8 is connected and the compressor 7 is driven again, time for preparing operation which inhibits drive of the compressor 7 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, the interior of a vehicle can be heated by supplying engine cooling water to a heater core disposed in an air conditioning unit inside the vehicle.

[0003]

However, in recent high-efficiency diesel engines and the like, since the temperature of the engine itself is suppressed from increasing, the temperature of the engine cooling water cannot be so much expected. Therefore, the heater core cannot quickly heat the interior of the vehicle, especially immediately after the engine is started, and it is difficult to obtain a comfortable air-conditioning state at an early stage.

Accordingly, an object of the present invention is to provide a vehicle air conditioner capable of quickly heating the inside of a vehicle even if the vehicle is equipped with a high-efficiency diesel engine or the like.

[0005]

According to the present invention, there is provided a vehicle air conditioner having a heater core in which an engine cooling water flows in an air conditioning unit. Water temperature detecting means for detecting a temperature, a clutch for transmitting or interrupting power from the engine to a compressor, and a first flow rate adjusting means for adjusting a flow rate of the heat exchange medium discharged from the compressor, the first pressure reducing means, and the compressor. Means, a first path in which a heat exchanger for exchanging heat between the heat exchange medium having passed through the first flow rate adjusting means and ambient air is connected in a ring shape, and a second pressure reducing means connected to the first flow rate adjusting means and the heat exchanger. And a second path in which the second flow control means and the second flow control means are connected in parallel, and a third flow control means, a vehicle exterior heat exchanger and a third pressure reducing means are provided in the first flow control means and the heat exchanger. When the heating / cooling operation can be performed by opening and closing the heat exchange medium circuit including the third path connected in a row and the third flow rate adjustment means, and the third flow rate adjustment means is closed to perform the heating operation, the water temperature detection means detects the temperature. If it is determined based on the cooling water temperature of the engine that the heating is insufficient with only the heater core, the clutch is connected to drive the compressor, while it is determined that heating is sufficient with only the heater core. A control unit for disconnecting the clutch, wherein the control unit temporarily disconnects the clutch and stops the compressor in the heating operation or the cooling operation, and then connects the clutch again to drive the compressor. , An operation preparation time for prohibiting the operation of the compressor.

With this configuration, in the heating operation, a sufficient amount of the heat exchange medium is supplied to the heat exchanger inside the vehicle immediately after the start of the compressor and the temperature of the engine cooling water is low. Heating can be started. Also, in any case of the cooling operation or the heating operation,
By operating a switch or the like, the air conditioning in the vehicle is temporarily stopped, or after the internal pressure of the compressor is excessively increased and automatically stopped, by providing an operation preparation time when the compressor is restarted, the inlet side of the flow rate adjusting means and It is possible to prevent the differential pressure from increasing on the outlet side and causing malfunctions.

When the control means corrects the operation preparation time on the basis of the outside air temperature, the vehicle speed, or the discharge pressure, it is possible to prevent the malfunction of the flow rate adjusting means from occurring based on the minimum necessary operation preparation time. It is preferable from the point of view.

[0008] After the cooling operation by the control means,
When performing the next operation, it is necessary to make the operation preparation time longer after the heating operation than when performing the next operation.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a vehicle air conditioner according to the present embodiment. In this air conditioner for a vehicle, a blower 2, a heat exchanger 3 inside a vehicle, an air mix damper 4, and a heater core 5 are provided in an air conditioning unit 1 inside the vehicle.
Are arranged.

The blower 2 is driven to rotate by the blower motor 6 to introduce outside air or inside air into the air conditioning unit 1.

The in-vehicle heat exchanger 3 is connected in the middle of a heat exchange medium circuit B in which a heat exchange medium is circulated by driving the compressor 7. The compressor 7 is driven by an engine 22 described later, and its driving force can be connected or disconnected by a clutch 8. In the heat exchange medium circuit B, the first path b1 to which the first capillary tube 9, the first flow rate control valve 10, and the muffler 11 are connected, and the second capillary tube 12 and the second flow rate control valve 13, are connected. 2nd route b2
And a third path b to which the third flow control valve 14, the vehicle exterior heat exchanger 15, and the third capillary tube 16 are connected
3 is comprised. A pressure detection sensor 17 and a temperature detection sensor 18 are provided near the discharge port of the compressor 7.
Is provided so that the pressure and temperature of the heat exchange medium discharged from the compressor 7 can be detected. The muffler 11 is for preventing the heat exchange medium that has passed through the first flow control valve 10 from generating abnormal noise in the vehicle interior heat exchanger 3. 19 and 20 are the first
A check valve and a second check valve, 21 is a compressor 7
This is an accumulator for preventing liquid from flowing into the accumulator.

The air mix damper 4 changes the rate at which the air heated or cooled by the heat exchanger 3 inside the vehicle is divided.
That is, by adjusting the amount of air heated by the heater core 5, it is used to adjust the temperature of air blown into the vehicle interior.

The heater core 5 is disposed in one of the flow paths divided by the air mix damper 4, and is provided with an engine 22.
Is connected to a circuit branched from a cooling water circuit A for cooling the cooling water by the radiator 23, so that the engine cooling water flows inside. A bypass passage a is connected in parallel to the radiator. The flow of the cooling water to the radiator 23 is allowed or blocked by the three-way valve 24. Further, the temperature of the cooling water flowing out of the engine 22 is detected by a water temperature detection sensor 25.

The connection and disconnection of the clutch 8 for driving and stopping the compressor 7, the switching of the three-way valve 24, the adjustment of the opening of the flow control valve 10, and the like are performed by detecting the temperature t detected by the water temperature detection sensor 25, The control is performed by the control device 26 based on the pressure p detected by the pressure detection sensor 17.

Next, the drive control of the vehicle air conditioner by the control device 26 will be described with reference to the flowcharts of FIGS.

First, various conditions inside and outside the vehicle such as the outside air temperature, inside air temperature, and the amount of solar radiation are read (step S1), and it is determined whether or not the inside heat exchanger 3 is used for cooling (step S2). When used for cooling, the third flow control valve 14 is opened (step S3), the heat exchange medium is radiated by the heat exchanger 15 on the outside of the vehicle, and the third capillary tube 1
By reducing the pressure in 6, the gas is vaporized in the heat exchanger 3 inside the vehicle. In this case, except for the case where the compressor 7 is restarted (Step S4), the driving speed of the compressor 7, the rotation position of the air mix damper 4, and the like are adjusted by a conventionally known method according to the various conditions inside and outside the vehicle. In-vehicle air conditioning is started (step S5). When the compressor 7 is restarted, the process waits until the operation preparation time elapses (step S6). This is because when the compressor 7 is restarted, the heat exchange medium circulates before that,
This is because a differential pressure is often generated at each part, particularly at the inlet side and the outlet side of the flow control valve 10, 13, or 14, and the compressor 7 may possibly fail in some cases.

On the other hand, when the in-vehicle heat exchanger is not used for cooling, the third flow control valve 14 is closed and the heating operation is started (step S7). In this heating operation, first, the temperature t detected by the water temperature detection sensor 25 is read (step S8). Then, it is determined whether or not the detected temperature t is higher than the first set temperature T1 (step S9). The first set temperature T1 is a maximum value (for example, 80 ° C.) that does not require cooling water to be radiated by the radiator 23 and cooled.

If the detected temperature t is higher than the first set temperature T1, it is necessary to cool the engine cooling water. Therefore, by switching the three-way valve 24, the cooling water is passed through the radiator 23 and cooled (step S10). Then, the clutch 8 is disconnected to stop driving the compressor 7 (step S11).

On the other hand, if the detected temperature t is equal to or lower than the first set temperature T1, the three-way valve 24 is switched so that the cooling water does not flow through the radiator 23 (step S12). It is determined whether it is higher than T2 (step S13). The second set temperature T2 is a minimum value at which the heater core 5 can sufficiently heat the air passing through the air conditioning unit 1.

If the detected temperature t is higher than the second set temperature T2, it is determined that the interior of the vehicle can be sufficiently heated only by the heater core 5, and the clutch 8 is disconnected and the driving of the compressor 7 is stopped as described above (step S14). ). On the other hand, if the detected temperature t is equal to or lower than the second set temperature T2, the interior of the vehicle cannot be sufficiently heated only by the heater core 5, and therefore, unless the compressor 7 is restarted (step S1).
5) The clutch 8 is connected, and the compressor 7 is driven to start auxiliary heating (step S17). When the compressor 7 is restarted, it waits until the operation preparation time elapses, as in step S6 (step S16).

In the auxiliary heating, the heat exchange medium is cooled by the in-vehicle heat exchanger 3. Therefore, depending on the opening of the motor valve, a decrease in the discharge pressure from the compressor 7 cannot be prevented. The pressure may drop to a value lower than the first set pressure P1 (for example, 8 kgf / cm ² G) that causes a stop or a failure. Therefore, the discharge pressure p from the compressor 7 is read (step S18), and it is determined whether or not the detected pressure p is lower than the first set pressure P1 (step S19).
If it becomes lower, the flow control valve 10 is closed (step S20). As a result, the flow into the heat exchanger 3 on the inside of the vehicle is prevented, and the flow rate flowing back to the compressor 7 through the second capillary tube 12 increases. As a result, the operating condition of the compressor 7 is satisfied, and abnormal stop, failure, and the like are prevented.

During the start and stop of the series of auxiliary heating, the detected pressure p is changed to the second set pressure P2 (for example, 2
It is determined whether it is higher than 0 kgf / cm ² G) (step S21). If the detected pressure p is higher than the second set pressure P2, it is determined that if driving in the compressor 7 is continued, there is a risk of failure, the power from the engine 22 is shut off by the clutch 8, and the compressor 7 is stopped. (Step S22). As a result, an unreasonable load is not applied to the engine 22, and the fuel consumption can be suppressed.

At this time, the opening of the flow control valve 10 is corrected upward (or fully opened) to promote cooling of the heat exchange medium. That is, since the pressure (temperature) of the heat exchange medium is higher on the compressor 7 side than on the inside heat exchanger 3 side, the heat exchange medium flows into the inside heat exchanger 3 side from the compressor 7 side. In addition, there is a flow of air outside the inside heat exchanger 3 as long as the inside air conditioning is performed. Therefore, when the opening of the flow control valve 10 is upwardly corrected (or fully opened), heat radiation of the heat exchange medium is promoted, and its temperature and pressure are reduced at an early stage to return the compressor 7 until the operating conditions are satisfied. Becomes possible. For example,
An electromagnetic on-off valve was used as the flow control valve 10, and after the compressor 7 was stopped, changes in the pressure and temperature of the heat exchange medium were compared between when the electromagnetic on-off valve was closed and when it was opened. As a result, as shown in the graph of FIG. 5A, the stop time of the compressor 7 was able to be shortened by opening the electromagnetic on-off valve. FIG.
As shown in the graph of (b), since the driving time of the compressor 7 becomes long, it became possible to raise the blowing temperature early.

Thereafter, when the operation of the engine 22 is continued, the temperature of the engine 22 itself rises, and the water temperature detection sensor 25
, The three-way valve 24 is automatically switched in step 9 as described above.
The engine cooling water is cooled by the radiator 23 (Step S10).

As shown in the graphs of FIGS. 6 to 8, it is preferable that the operation preparation time is set to a value corresponding to any one parameter among the outside air temperature, the vehicle speed, and the blower air volume. This makes it possible to minimize the time required to reduce the differential pressure to a value that does not hinder the restart of the compressor 7 in consideration of the parameters that affect the flow state of the heat exchange medium. Further, it is more preferable that the operation preparation time is adjusted so that a value obtained when the next operation is performed after the cooling operation is larger than a value obtained when the next operation is performed after the heating operation. Thus, the time required for further reducing the differential pressure can be appropriately determined in consideration of the difference in the operation mode.

In the above-described embodiment, the flow path is switched by the three-way valve 24. However, the flow of water not only to the radiator 23 but also to the heater core 5 may be stopped by appropriately providing an open / close valve. Good.

[0027]

As is apparent from the above description, according to the present invention, if it is determined that heating is insufficient with only the heater core, the clutch is connected to drive the compressor. By using the heater for auxiliary heating, the interior heating can be started early.

In addition, the operation preparation time is provided when the compressor is restarted after the air conditioning in the vehicle is temporarily stopped or the compressor is automatically stopped due to the internal pressure of the compressor becoming too large by operating a switch or the like. The valve will not be restarted with the pressure difference between the inlet and outlet sides of the valve being generated, and the compressor can be prevented from being broken down.

In particular, the operation preparation time depends on the outside air temperature, the vehicle speed,
Or, based on the discharge pressure, or after the cooling operation, after performing the next operation, after the heating operation, longer than when performing the next operation, occurred in the middle of the flow path of the heat exchange medium It is possible to appropriately eliminate the differential pressure.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating air conditioning control by the control device of FIG. 1;

FIG. 3 is a flowchart illustrating air conditioning control by the control device of FIG. 1;

FIG. 4 is a flowchart showing air conditioning control by the control device of FIG. 1;

5 is a graph showing a change in pressure (a) and a change in temperature (b) of the heat exchange medium when the flow control valve of FIG. 1 is opened or closed. FIG.

FIG. 6 is a graph showing a relationship between outside air temperature and operation preparation time.

FIG. 7 is a graph showing a relationship between a vehicle speed and a driving preparation time.

FIG. 8 is a graph showing a relationship between a blower air volume and an operation preparation time.

[Description of Signs] 1 ... Air-conditioning unit 2 ... Blower 3 ... Inside heat exchanger 4 ... Air mix damper 5 ... Heater core 7 ... Compressor 8 ... Clutch 9 ... First capillary tube 10 ... First flow control valve 12 ... Second Capillary tube 13 Second flow control valve 14 Third flow control valve 15 Outside heat exchanger 16 Third capillary tube 17 Pressure detection sensor 18 Temperature detection sensor 22 Engine 23 Radiator 24 Three-way valve 25 … Water temperature detection sensor 26… Control device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60H 1/32 624 B60H 1/32 624H

Claims (5)

[Claims] 1. A vehicle air conditioner having a heater core in which an engine cooling water flows in an air conditioning unit, wherein a water temperature detecting means for detecting a temperature of the engine cooling water, and a power from the engine to a compressor. Or a clutch to be shut off, the compressor, the first pressure reducing means, a first flow rate adjusting means for adjusting a flow rate of the heat exchange medium discharged from the compressor, and a heat exchange medium and ambient air passing through the first flow rate adjusting means. A first path in which a heat exchanger that exchanges heat with the first path is annularly connected, a second path in which a second pressure reducing means and a second flow rate adjusting means are connected in parallel to the first flow rate adjusting means and the heat exchanger, and A heat exchange medium circuit including a third path in which the third flow rate adjusting means, the vehicle exterior heat exchanger, and the third pressure reducing means are connected in parallel to the first flow rate adjusting means and the heat exchanger; When the heating / cooling operation can be performed by opening and closing the regulating means and the heating operation is performed with the third flow rate regulating means closed, heating is not possible only with the heater core based on the engine coolant temperature detected by the coolant temperature detecting means. When it is determined that the heating is sufficient, the compressor is driven by connecting the clutch, and when it is determined that heating is sufficient only by the heater core, control means for disconnecting the clutch is provided. In the heating operation or the cooling operation, the clutch is temporarily stopped to stop the compressor, and then, when the clutch is connected again to drive the compressor, an operation preparation time for prohibiting the driving of the compressor is set. Vehicle air conditioner. 2. The vehicle air conditioner according to claim 1, wherein the control unit corrects the operation preparation time based on an outside air temperature. 3. The vehicle control apparatus according to claim 1, further comprising a vehicle speed detecting unit configured to detect a vehicle speed, wherein the control unit corrects the driving preparation time based on the vehicle speed detected by the vehicle speed detecting unit. A vehicle air conditioner according to claim 1. 4. A pressure detecting means for detecting a discharge pressure from the compressor, wherein the control means corrects the operation preparation time based on the discharge pressure detected by the pressure detecting means. The vehicle air conditioner according to claim 1, wherein: 5. The system according to claim 1, wherein the control unit makes the operation preparation time longer when the next operation is performed after the cooling operation than when the next operation is performed after the heating operation.
A vehicle air conditioner according to claim 1.