JP4308419B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner.
[0002]
[Prior 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]
[Problems to be solved by the invention]
However, recent high-efficiency diesel engines and the like are configured to suppress the temperature rise of the engine itself, and thus the temperature rise of the engine cooling water cannot be expected so much. For this reason, in the said heater core, the inside of a vehicle cannot be heated rapidly immediately after engine starting, and it is difficult to obtain a comfortable air-conditioning state at an early stage.
[0004]
Then, even if it is a vehicle carrying a highly efficient diesel engine etc., this invention makes it a subject to provide the vehicle air conditioner which can heat the inside of a vehicle rapidly.
[0005]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, the present invention provides a vehicle air conditioner including a heater core through which engine coolant flows in an air conditioning unit.
Water temperature detecting means for detecting the cooling water temperature of the engine;
A clutch for transmitting or shutting off the power from the engine to the compressor;
The compressor, the first pressure reducing means for reducing the pressure of the heat exchange medium discharged from the compressor, the flow rate adjusting means for adjusting the flow rate of the heat exchange medium reduced in pressure by the first pressure reducing means, and the heat exchange medium that has passed through the flow rate adjusting means A heat exchange medium circuit in which a vehicle interior heat exchanger that exchanges heat with ambient air is annularly connected, and a second decompression device is connected in parallel to the first decompression device, the flow rate adjustment device, and the vehicle interior heat exchanger. When,
Based on the engine coolant temperature detected by the water temperature detection means, if it is determined that heating is not sufficient with only the heater core, it is determined that the clutch is connected and the compressor is driven while it is sufficient. And a control means for disengaging the clutch.
[0006]
With this configuration, when the temperature detected by the water temperature detecting means is low and heating is insufficient with only the heater core, the clutch is connected to drive the compressor. As a result, the heat exchange medium discharged from the compressor is decompressed by the first decompression means and then flows into the in-vehicle heat exchanger at a predetermined flow rate via the flow rate adjusting means. Therefore, such a large pressure resistance is not required for the vehicle interior heat exchanger. Further, the heating by the heat exchanger is not interrupted and the heating by the heater core can be assisted in a stable state without being interrupted.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the accompanying drawings.
[0010]
FIG. 1 is a schematic view of a vehicle air conditioner according to the present embodiment. In this vehicle air conditioner, a heater core 2 and a vehicle interior heat exchanger 3 are arranged in an air conditioning unit 1 on the vehicle interior side.
[0011]
The heater core 2 is connected to a circuit branched from the cooling water circuit A that cools the cooling water of the engine 4 by the radiator 5, and the engine cooling water flows inside. A bypass passage a is connected to the radiator 5 in parallel. The flow of the cooling water to the radiator 5 is allowed or blocked by the three-way valve 6. The temperature of the cooling water flowing out from the engine 4 side is detected by a water temperature detection sensor 7.
[0012]
The vehicle interior heat exchanger 3 is connected in the middle of the heat exchange medium circuit B in which the heat exchange medium circulates by driving the compressor 8. The compressor 8 is driven by the engine 4, and the driving force can be connected or disconnected by a clutch 9. A first capillary tube 13a, a flow rate adjusting valve 10 and a muffler 11 are connected between the discharge port of the compressor 8 and the suction port of the vehicle interior heat exchanger 3. A pressure detection sensor 12 is provided in the vicinity of the discharge port of the compressor 8 to detect the pressure of the heat exchange medium discharged from the compressor 8. The muffler 11 prevents the heat exchange medium that has passed through the flow rate adjusting valve 10 from generating abnormal noise in the vehicle interior heat exchanger 3. The flow rate adjusting valve 10, the muffler 11, and the vehicle interior heat exchanger 3 are connected in parallel with a second capillary tube 13b that is a second pressure reducing means. Reference numerals 14 and 15 denote a first check valve and a second check valve, and reference numeral 16 denotes an accumulator for preventing liquid from flowing into the compressor 8.
[0013]
Connection and disconnection of the clutch 9 for driving and stopping the compressor 8, switching of the three-way valve 6, adjustment of the opening degree of the flow rate adjusting valve 10, etc. This is performed by the control device 17 based on the detected pressure p at 12.
[0014]
Next, drive control of the vehicle air conditioner by the control device 17 will be described with reference to the flowchart of FIG.
[0015]
If the engine 4 is started and heating by the vehicle air conditioner is started (step S1), the temperature t detected by the water temperature detection sensor 7 is read (step S2). Then, it is determined whether or not the detected temperature t is lower than the first set temperature T1 (step S3). The first set temperature T1 is set to a maximum value (for example, 80 ° C.) that does not require cooling of the cooling water by dissipating it with the radiator 5.
[0016]
If the detected temperature t is equal to or higher than the first set temperature T1, the engine cooling water needs to be cooled. Therefore, by switching the three-way valve 6 (step S13), the water is passed through the radiator 5 for cooling.
[0017]
On the other hand, if the detected temperature t is lower than the first set temperature T1, the three-way valve 6 is switched so that the cooling water does not pass through the radiator 5 (step S4), and the detected temperature t is lower than the second set temperature T2. It is determined whether or not it is low (step S5). The second set temperature T2 is a minimum value at which the air passing through the air conditioning unit 1 by the heater core 2 can be sufficiently heated.
[0018]
If the detected temperature t is equal to or higher than the second set temperature T2, it is determined that the vehicle interior can be sufficiently heated only by the heater core 2, and similarly to the above, the clutch 9 is disconnected and the drive of the compressor 8 is stopped (step S14). On the other hand, if the detected temperature t is lower than the second set temperature T2, the interior of the vehicle cannot be sufficiently heated only by the heater core 2, so the clutch 9 is connected and the compressor 8 is started (step S6).
[0019]
When driving the compressor 8, the opening degree of the flow rate adjustment valve 10 is adjusted according to the detected pressure p of the pressure detection sensor 12.
[0020]
Here, first, the detected pressure p at the pressure detection sensor 12 is read (step S7). Then, it is determined whether or not the detected pressure p is higher than a first set pressure P1 (for example, 18 kgf / cm ² G) (step S8). If the detected pressure p is higher than the first set pressure P1, auxiliary heating by the vehicle interior heat exchanger 3 is started by opening the flow rate adjusting valve 10 (step S9). Thereby, the heating by the vehicle interior heat exchanger 3 is started, and the heating by the heater core 2 is assisted. Therefore, the air passing through the air conditioning unit 1 can be heated early.
[0021]
In this case, the heat exchange medium discharged from the compressor 8 is decompressed by the first capillary tube 13 a, and then the flow rate is adjusted by the flow rate adjusting valve 10 and flows into the vehicle interior heat exchanger 3. For this reason, a special pressure | voltage resistant structure is unnecessary for the vehicle interior heat exchanger 3, and the heat exchanger of the general structure used for cooling can be used.
[0022]
On the other hand, if the detected pressure p is equal to or lower than the first set pressure P1, it is determined that the auxiliary heating by the vehicle interior heat exchanger 3 cannot be sufficiently performed, and the flow rate adjusting valve 10 is closed (step S10).
[0023]
By the way, in the auxiliary heating, since the heat exchange medium is cooled by the vehicle interior heat exchanger 3, the discharge pressure from the compressor 8 decreases, and a second set pressure P2 (for example, the compressor 8 abnormally stops or fails) (for example, , 8 kgf / cm ² G). Therefore, it is determined whether or not the detected pressure p is lower than the second set pressure P2 (step S11). If the detected pressure p becomes lower than the second set pressure P2, the flow rate adjustment valve 10 is closed (step S11). S10), auxiliary heating is stopped. Thereby, the inflow to the vehicle interior heat exchanger 3 is blocked, and the flow rate of returning to the compressor 8 through the second capillary tube 13b increases. As a result, the operating condition of the compressor 8 is satisfied, and an abnormal stop or failure is prevented.
[0024]
Further, during the start and stop of the series of auxiliary heating, it is determined whether or not the detected pressure p is higher than a third set pressure P3 (for example, 20 kgf / cm ² G) (step S13). If the detected pressure p is higher than the third set pressure P3, it is determined that there is a risk of failure if the drive in the compressor 8 is continued, the power from the engine 4 is cut off by the clutch 9, and the compressor 8 is stopped. (Step S14). As a result, an excessive load is not applied to the engine 4 and fuel consumption can be suppressed.
[0025]
At this time, the opening of the flow rate adjusting valve 10 is corrected upward (or fully opened) to promote cooling of the heat exchange medium. That is, the heat exchange medium flows from the compressor 8 side to the vehicle interior heat exchanger 3 side because the pressure (temperature) is higher on the compressor 8 side than the vehicle interior heat exchanger 3 side. In addition, there is an air flow outside the vehicle interior heat exchanger 3 as long as the vehicle air conditioning is performed. Therefore, when the opening degree of the flow rate adjusting valve 10 is corrected upward (or fully opened), the heat dissipation of the heat exchange medium is promoted, and the temperature and pressure are lowered at an early stage to return the compressor 8 to a state satisfying the operating conditions. It becomes possible. For example, when an electromagnetic on-off valve is used as the flow rate adjusting valve 10 and the compressor 8 is stopped, changes in the pressure and temperature of the heat exchange medium are compared between when the electromagnetic on-off valve is closed and when the electromagnetic on-off valve is opened. . As a result, as shown in the graph of FIG. 3A, the stop time of the compressor 8 could be shortened by opening the electromagnetic on-off valve. Further, as shown in the graph of FIG. 3B, the driving time of the compressor 8 becomes longer, so that the outlet temperature can be raised at an early stage.
[0026]
Thereafter, when the driving of the engine 4 is continued, the temperature of the engine 4 rises, and the detected temperature t detected by the water temperature detection sensor 7 also rises. The three-way valve 6 is switched, and the engine coolant is cooled by the radiator 5 (step S13).
[0027]
In the above-described embodiment, the flow path is switched by the three-way valve 6, but the flow of water not only to the radiator 5 but also to the heater core 2 may be stopped by appropriately providing an on-off valve or the like.
[0028]
Further, in the flow rate adjusting valve 10, it is switched to either the open state or the closed state, but the opening degree may be changed stepwise or continuously in accordance with the detected discharge pressure. As a result, it is possible to maximize the heating by the vehicle interior heat exchanger 3 under conditions where the compressor 8 does not stop.
[0029]
Thus, according to the vehicle air conditioner, when the cooling water temperature of the engine 4 has not increased so much, the driving load of the engine 4 is increased by driving the compressor 8 and the compressor 8 is not driven. Compared with this, heating of the cooling water can be promoted. Therefore, the amount of heat given to the passing air by the heater core 2 can be increased.
[0030]
Moreover, since the heating by the vehicle interior heat exchanger 3 is also started, the vehicle interior heating can be performed more rapidly. That is, the heat exchange medium brought to a high temperature and high pressure state by the compressor 8 flows into the vehicle interior heat exchanger 3 through the flow rate adjusting valve 10 and the muffler 11 and heats the air passing through the external air conditioning unit 1. The heating of air, which is insufficient with only the heater core 2, is assisted.
[0031]
The operating condition of the compressor 8 is determined based only on the discharge heat exchange medium pressure, but is determined based on the suction heat exchange medium pressure or the discharge heat exchange medium temperature, or any combination of these three conditions. May be. For example, when determining based on the suction heat exchange medium pressure, as shown in FIG. 4, when the suction heat exchange medium pressure exceeds 0.58 MPa, the clutch 9 is connected and the compressor 8 is turned off, and the suction heat exchange The clutch 9 may be disconnected and the compressor 8 may be turned on when the exchange medium pressure becomes lower than 0.5 MPa.
[0032]
FIG. 5 is a schematic view of a vehicle air conditioner according to another embodiment.
[0033]
In this vehicle air conditioner, a flow rate adjusting valve 20 is used in place of the second check valve 15, and the first capillary tube 13a, the flow rate adjusting valve 10 and the muffler 11 are provided with a flow rate adjusting valve 21 and an outside heat exchanger. 22, the third capillary tube 23 and the third check valve 24 are connected in parallel. In the air conditioning unit, an air mix damper 25 is provided on the downstream side of the vehicle interior heat exchanger 3, and the heater core 2 is provided in one of the branched passages.
[0034]
When heating the interior of the vehicle, the flow rate adjustment valve 21 is closed and the flow rate adjustment valves 10 and 20 are opened so that the heat exchange medium discharged from the compressor 8 directly flows into the vehicle interior heat exchanger 3. When the interior of the vehicle is cooled, the heat exchange medium discharged from the compressor 8 passes through the vehicle interior heat exchanger 3 from the vehicle exterior heat exchanger 18 via the capillary tube 23 and then returns to the compressor 8. Then, the flow rate adjusting valves 10 and 20 are closed, and the flow rate adjusting valve 21 is opened.
[0035]
In each of the embodiments described above, two pressure reducing means are provided, but these may be constituted by a single pressure reducing means. For example, by connecting one end portion of the capillary tube to the vehicle interior heat exchanger 3 side and connecting the intermediate portion to the detour, the pressure reducing means can be made one, and the configuration can be simplified. Become.
[0036]
In each of the above embodiments, the clutch and the like are automatically driven and controlled based on the input signal from the pressure detection sensor 12 and the like. You may enable it to adjust by manual operation based on sense. That is, even if auxiliary heating is not performed, if the passenger feels cold, by operating the input means, a drive request signal for the compressor 8 is output and the clutch 9 is connected. The compressor 8 may be turned on so that auxiliary heating by the vehicle interior heat exchanger 3 can be started. As a result, it is possible to easily correct the blast temperature upward according to the passenger's preference.
[0037]
In this case, the vehicle air conditioner shown in FIG. 5 will be described. The drive request signal for the compressor 8 can be received only when the air mix damper 25 is in the full hot position (indicated by a dotted line in FIG. 5). That's fine. In other words, if the vehicle interior can be sufficiently heated only by the heating by the heater core 2, the air blowing temperature can be corrected upward by changing the rotational position of the air mix damper 25 without driving the compressor 8. Therefore, the drive request signal for the compressor 8 is not accepted. On the other hand, when the air mix damper 25 is in the full hot position, it is impossible to raise the air blowing temperature any further, so that a drive request signal for the compressor 8 can be received. As a result, useless load is applied to the engine 4 and fuel is not consumed uselessly.
[0038]
【The invention's effect】
As apparent from the above description, according to the vehicle air conditioner according to the present invention, the heat exchange medium circuit formed by connecting the pressure reducing means to the flow rate adjusting means and the vehicle interior heat exchanger in parallel is provided. When the engine coolant temperature has not risen sufficiently, the compressor can be driven to increase the engine drive load, and the coolant temperature can be forcibly raised early. As a result, heating by the heater core is possible from the initial stage of engine start, and the interior of the vehicle can be appropriately heated. In particular, since the heat exchange medium passes through the decompression means before flowing into the vehicle interior heat exchanger, the pressure resistant structure is adopted even when the vehicle interior heat exchanger is used as auxiliary heating for the heater core. It is not necessary and can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic view of a vehicle air conditioner according to an embodiment.
FIG. 2 is a flowchart showing air conditioning control by the control device of FIG. 1;
FIG. 3 is a graph showing a change in pressure (a) and a change in temperature (b) of a heat exchange medium compared when the flow rate adjustment valve of FIG. 1 is in a closed state or an open state.
4 is a graph showing clutch connection and disconnection timings with respect to suction heat exchange medium pressure to the compressor of FIG. 1; FIG.
FIG. 5 is a schematic view of a vehicle air conditioner according to another embodiment.
[Explanation of symbols]
2 ... Heater core 3 ... Inside heat exchanger 4 ... Engine 5 ... Radiator 6 ... Three-way valve 7 ... Water temperature detection sensor 8 ... Compressor 9 ... Clutch 10 ... Flow rate adjustment valve 12 ... Pressure detection sensor 13a ... First caprary tube (No. 1) 1 decompression means)
13b ... second caprary tube (second decompression means)
17 ... Control device 22 ... Outside heat exchanger

Claims (1)

In a vehicle air conditioner equipped with a heater core through which the engine coolant flows in the air conditioning unit,
Water temperature detecting means for detecting the cooling water temperature of the engine;
A clutch for transmitting or shutting off the power from the engine to the compressor;
The compressor, the first pressure reducing means for reducing the pressure of the heat exchange medium discharged from the compressor, the flow rate adjusting means for adjusting the flow rate of the heat exchange medium reduced in pressure by the first pressure reducing means, and the heat exchange medium that has passed through the flow rate adjusting means A heat exchange medium circuit in which a vehicle interior heat exchanger that exchanges heat with ambient air is annularly connected, and a second decompression device is connected in parallel to the first decompression device, the flow rate adjustment device, and the vehicle interior heat exchanger. When,
A discharge pressure detecting means for detecting the pressure of the heat exchange medium discharged from the compressor, a suction pressure detecting means for detecting the pressure of the heat exchange medium sucked into the compressor, or a heat exchange medium discharged from the compressor At least any two of the discharge temperature detecting means for detecting the temperature; and
Based on the engine coolant temperature detected by the water temperature detection means, if it is determined that heating is not sufficient with only the heater core, it is determined that the clutch is connected and the compressor is driven while it is sufficient. And a control means for adjusting the flow rate by the flow rate adjusting means so as to satisfy the operating condition of the compressor based on a detection signal from at least one of the two detection means . The vehicle air conditioner characterized by the above-mentioned.

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