JP2000211345A - Vehicle air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve rapid cooling and heating, and in particular, excellent heating capability. SOLUTION: An oil cooler 40 for cooling engine oil is provided in a cooling- water bypass flow passage b2. A heater-core bypass flow passage b4 is connected in parallel with a heater core 11. An auxiliary heat exchanger 12 is provided for conducting heat exchange between a heat-exchange medium flowing in a heat-exchange-medium flow passage a and engine cooling water flowing in the heater-core bypass flow passage b4.

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, and more particularly to a vehicle air conditioner having an auxiliary heating function.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, as shown in FIG. 6, a cooling cycle A comprising a compressor 1, a condenser 2, an accumulator 3, a throttle valve 4 and an evaporator 5 and an engine cooling cycle B are provided in the middle. And a heater core 6.

In the engine cooling cycle B, in addition to the heater core 6, a water pump 8, a radiator 9, a bypass passage 10a, and a water passage switching member 10b provided in the engine 7 are provided. The heater core 6, the radiator 9, and the bypass passage 10a are connected in parallel. The water passage switching member (thermostat valve) 10b allows water to flow through the bypass passage 10a until the engine cooling water reaches a predetermined temperature, and flows through the radiator 9 when the engine cooling water reaches the predetermined temperature.

[0004]

However, for example, in a recent high-efficiency diesel engine or the like, the temperature of the engine 7 does not rise, and therefore the temperature of the engine cooling water cannot be so much expected. Therefore, if the temperature of the engine cooling water is used by the heater core 6 as in the conventional vehicle air conditioner, it is difficult to quickly heat the inside of the vehicle.

In the conventional vehicle air conditioner, when cooling the interior of the vehicle, the refrigerant is circulated and radiated to the outside air by the condenser 2, and is vaporized by the evaporator 5 to absorb heat from the air blown into the vehicle. In this case, if the outside air temperature is high, heat radiation to the outside of the vehicle by the condenser 2 does not go smoothly, and rapid cooling is difficult.

[0006] Accordingly, the present invention provides rapid cooling and heating,
It is an object to provide a vehicle air conditioner having excellent heating performance.

[0007]

According to the present invention, there is provided a cooling / heating cycle having a compressor, an outside heat exchanger, and an inside heat exchanger in a heat exchange medium flow path as means for solving the above problems. In a vehicle air conditioner comprising a heater core provided in a heater core flow path connected in parallel to a radiator flow path having a radiator, an oil cooler for cooling engine oil is provided upstream of the heater core in the heater core flow path, while the heater core and A heater core bypass flow path was connected in parallel, and an auxiliary heat exchanger for performing heat exchange between a heat exchange medium flowing through the heat exchange medium flow path and engine cooling water flowing through the heater core bypass flow path was provided. Things.

With this configuration, when heating the inside of the vehicle, the engine cooling water receives heat not only from the engine but also from the engine oil flowing through the oil cooler, and radiates heat to the heat exchange medium by the auxiliary heat exchanger. As a result, the heating capacity of the heat exchanger inside the vehicle is improved. When cooling the interior of the vehicle, the engine cooling water absorbs heat from the heat exchange medium in the auxiliary heat exchanger. Thus, the cooling capacity of the heat exchanger inside the vehicle is improved.

If an oil cooler bypass flow path is connected in parallel with the oil cooler and if the desired viscosity of the oil is not obtained, oil bypass means for diverting the oil to the oil cooler bypass flow path is provided. This is preferable in that poor lubrication due to insufficient oil circulation due to the increase can be prevented.

The flow rate adjusting means for adjusting the flow rate of the engine coolant to the auxiliary heat exchanger, the pressure detecting means for detecting the discharge pressure of the heat exchange medium from the compressor, and the compressor satisfying a driving condition. Control means for judging whether or not there is pressure based on the pressure detected by the pressure detecting means, and adjusting the flow rate to the auxiliary heat exchanger by the flow rate adjusting means so as to satisfy the driving condition. You may.

[0011] With this configuration, when the discharge pressure detected by the pressure detecting means becomes too high and the compressor may be forcibly stopped, the flow rate to the auxiliary heat exchanger is suppressed by the flow rate adjusting means. . As a result, the temperature of the heat exchange medium decreases, and the suction pressure and the discharge pressure of the compressor decrease, so that the compressor stops and the heating by the in-vehicle heat exchanger is not stopped.

In this case, a radiator bypass flow path is connected in parallel with the radiator flow path, and the radiator bypass flow path is provided with water temperature detecting means for detecting the temperature of engine cooling water, and the flow rate to the heater core is adjusted. Second
Is provided, and the control means estimates the heating capacity of the in-vehicle heat exchanger based on the pressure detected by the pressure detection means, based on the estimation result and a change in engine coolant temperature. After adjusting the flow rate to the heater core so that the blower temperature does not fluctuate significantly, if it is determined that the desired heating capacity can be obtained in the heater core based on the temperature detected by the water temperature detecting means, the driving of the compressor is stopped. You may.

[0013] With this configuration, it is possible to gradually shift to heating by the heater core while suppressing the heating capacity of the heat exchanger inside the vehicle, and thereafter, the temperature of the air blown into the vehicle rapidly changes even if the compressor is stopped. Nothing.

[0014]

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

The vehicle air conditioner shown in FIG. 1 has a heating / cooling cycle A, a heater core 11 disposed in the middle of an engine cooling cycle B, and auxiliary heat exchange provided in both the cooling / heating cycle A and the engine cooling cycle B. And a vessel 12.

In the cooling / heating cycle A, the heat exchange medium flow path a
, A compressor 13, an outside heat exchanger 14, and an inside heat exchanger 15 are provided, and a heat exchange medium circulates in two directions via a four-way valve 16. The auxiliary heat exchanger 12 is provided between the vehicle exterior heat exchanger 14 and the four-way valve 16.
Is provided. The auxiliary heat exchanger 12 may be of any type such as a double tube type, a shell and coil type, a plate type, etc. In short, a heat exchange medium circulating in the cooling / heating cycle A and an engine cooling cycle described below What is necessary is just to be able to exchange heat with the engine cooling water circulating B.

In the middle of the heat exchange medium flow path a, a bypass flow path a1 is provided in parallel with the vehicle exterior heat exchanger 14. Channels a2 and a3 extending from heat exchanger 14 outside the vehicle
Are provided with a first electromagnetic on-off valve 17 and a check valve 18, respectively, so that the inflow of the heat exchange medium from the auxiliary heat exchanger 12 to the vehicle-side heat exchanger 14 can be prevented. A check valve 19 that allows the heat exchange medium to flow only from the in-vehicle heat exchanger 15 to the auxiliary heat exchanger 12 is provided in the bypass passage a1. The pressure of the heat exchange medium discharged from the compressor 13 is detected by a pressure detection sensor 20.

Reference numeral 21 denotes a means for expanding the heat exchange medium, which may employ any method such as a capillary tube, a temperature expansion valve, a conduction expansion valve, etc., so that the heat exchange medium passing therethrough is easily vaporized. Reference numeral 22 denotes an accumulator for gas-liquid separation.

In the engine cooling cycle B, the engine 2
A radiator flow path b1 having a radiator 24 and a heater core flow path b2 having a heater core 11 are provided in parallel in the middle of an engine cooling water path b extending from 3.

The heater core 11 of the heater core channel b2
An oil cooler 40 is disposed upstream of the oil cooler. Oil from the engine 23 flows through the oil cooler 40 through the oil flow path b5, and can exchange heat with engine cooling water passing through the heater core flow path b2.
Further, an oil bypass flow path b6 is connected in parallel with the oil cooler 40, and the flow path switching member 42 allows oil to flow through one of them. The flow path switching member 42 automatically switches according to the viscosity of the oil. As the usable flow path switching member 42,
A thermostat valve may be used. In short, if the temperature is lower than a predetermined temperature based on the temperature of the oil, the configuration is switched to the oil bypass flow path b6 side, and if the temperature is high, the configuration is switched to the oil cooler 40 side. .

The radiator 24 includes a water channel switching member 2.
5, a first cooling water bypass flow path b3 is connected in parallel. A second cooling water bypass flow path b4 is connected in parallel to the heater core 11. In the middle of the second cooling water bypass channel b2, a water temperature detection sensor 41 for detecting the temperature of the engine cooling water and the auxiliary heat exchanger 12 are provided. The water passage switching member 25 shuts off the supply of the engine cooling water to the radiator 24 until the temperature of the engine cooling water exceeds the first set temperature (80 ° C. in the present embodiment), and allows the supply of the engine cooling water after the temperature is exceeded. It is designed to switch. Further, the heater core 11 and the auxiliary heat exchanger 12
Upstream and downstream of the second solenoid valve 26 and the third solenoid valve 27
Are provided respectively.

The heat exchanger 15 and the heater core 1 inside the vehicle
As shown in FIG. 2, 1 is disposed in a blower unit 28 provided at a front part in the vehicle. Inside the blower unit 28, in order from the upstream side, a blower 29,
5. An air mix damper 30 is provided, and the heater core 11 is provided in one of the flow paths divided by the air mix damper 30.

The detection signals from the pressure detection sensor 20 and the water temperature detection sensor 41 are input to a control device 31. The control device 31 drives and controls the first, second, and third solenoid on-off valves 17, 26, 27, and the like based on these detection signals as described later.

Next, the operation of the vehicle air conditioner will be described.

First, the operation in the engine cooling cycle B will be described.

When the engine 23 is started, the engine cooling water flows through the engine cooling water passage b. At this time, if the temperature of the engine cooling water does not exceed 80 ° C., it is determined that cooling is not necessary, and the water passage switching member 25 is switched to prevent the passage of water to the radiator 24. As a result, when the engine coolant is not so warmed immediately after the start of the engine, the radiator 24 does not cool the engine coolant.

The engine oil is supplied to an oil cooler 4.
At 0, heat is released from this oil to the engine cooling water. This makes it possible to heat the engine cooling water effectively. However, when the viscosity of the oil is high, the oil is diverted to the oil bypass flow path b6 by the flow path switching member 42. This prevents the high-viscosity oil from staying in the oil cooler 40 and causing poor lubrication of the engine due to insufficient oil circulation.

The oil temperature changes from the start of the start of the engine 23, for example, as shown in the graph of FIG. Here, if the oil temperature is about 35 ° C. or lower, it is determined that the oil viscosity is high and the oil may stay in the oil cooler 40. Therefore, the oil temperature is about 35 ° C
Is exceeded, the flow path switching member 42 is switched so that the oil flows through the oil cooler 40. This allows
It is possible to quickly release heat from the oil to the engine cooling water without damaging the oil cooler 40.

On the other hand, if the temperature of the engine cooling water exceeds 80 ° C., the water channel switching member 25 switches, and the flow of water to the first cooling water bypass flow path b3 is prevented. As a result, the engine cooling water flows through the radiator 24 and is radiated to the outside air.

The second and third solenoid on-off valves 26 and 2
The drive control of 7 will be described in the following description of the operation of the cooling / heating cycle A.

Next, the operation of the cooling / heating cycle A will be described.

In the case of heating, that is, when a heat pump switch (not shown) is operated, the four-way valve 16 switches as shown by a solid line, and a so-called heat pump cycle is formed. At this time, the first electromagnetic on-off valve 17 prevents the heat exchange medium from flowing into the vehicle-side heat exchanger 14.
Thereby, the heat exchange medium discharged from the compressor 13 circulates back to the compressor 13 from the vehicle interior heat exchanger 15, the expansion valve 21, the auxiliary heat exchanger 12, and the accumulator 18. In this case, the heat exchange medium is the auxiliary heat exchanger 1
2, the flow resistance increases, but the closing operation of the first solenoid on-off valve 17 does not allow the heat exchange medium to circulate through the vehicle-side heat exchanger 14, so that the load on the compressor 13 increases. I will not do it. The heat exchange medium is made high temperature and high pressure by the compressor 13 and heat exchanger 1 inside the vehicle.
5 and heats the air passing through the blower unit 25. Then, the auxiliary heat exchanger 12 absorbs heat from the engine cooling water. Therefore, the heat exchange medium returns to the compressor 13 with the heat capacity increased. For this reason, in the present embodiment, the discharge pressure of the compressor 13 is set to about 2.
6MPa, the condensation temperature can be about 80 ° C, and it is possible to exhibit a very high heating capacity.

When the heating performance of the heat exchanger 15 inside the vehicle is improved in this way, the temperature of the heat exchange medium rises too much, so that the suction and discharge pressures of the heat exchange medium in the compressor 13 are reduced. In some cases, the driving conditions may not be satisfied. In this case, if the driving of the compressor 13 is forcibly stopped before the compressor 13 is damaged based on the pressure detected by the pressure detection sensor 20, the heat generated by the in-vehicle heat exchanger 13 contributing to the heating of the interior of the vehicle is reduced. Heating is suddenly stopped, and the blowing temperature fluctuates greatly, which is not preferable. Therefore, in the present embodiment, before the pressure detected by the pressure detection sensor 20 reaches a value at which the driving of the compressor 13 is stopped, the third cycle of the engine cooling cycle B is performed.
The electromagnetic on-off valve 27 is gradually closed to reduce the flow rate of the engine coolant in the auxiliary heat exchanger 12. As a result, the amount of heat transferred from the engine cooling water to the heat exchange medium decreases, and the suction and discharge pressure of the heat exchange medium in the compressor 13 is suppressed, so that the compressor 13 does not stop.

Further, the second solenoid valve 26 is gradually opened in accordance with the degree of temperature rise of the engine cooling water to increase the amount of water flowing to the heater core 11. Thereby, the heater core 11 is gradually increased so as to compensate for the decrease in the heating capacity in the in-vehicle heat exchanger 15 due to the suppression of the amount of heat exchanged in the auxiliary heat exchanger 12.
Increases the heating capacity. When the temperature of the engine cooling water rises sufficiently (about 70 ° C. in the present embodiment) and the interior of the vehicle can be sufficiently heated only by the heater core 11, the driving of the compressor 13 is stopped and the engine 2 is stopped.
3 to reduce the load. Further, the third electromagnetic opening / closing valve 27 shuts off the flow of the engine cooling water to the auxiliary heat exchanger 12 and increases the flow rate of the engine cooling water to the heater core 11. In this manner, the heating can be smoothly switched from the heating by the heat exchanger 15 inside the vehicle to the heating by the heater core 11 in accordance with the degree of temperature rise of the engine cooling water. I do not receive it.

The timing at which the second solenoid on-off valve 26 is opened is set at an arbitrary timing according to differences in environmental conditions such as the outside air temperature, the temperature rise of the engine 23, the heating performance of the heat exchanger 15 inside the vehicle, and the like. Become. Until the discharge pressure of the heat exchange medium from the compressor 13 is stabilized, the heating capacity in the in-vehicle heat exchanger 15 is estimated based on the discharge pressure, and the second electromagnetic on-off valve 26 is determined based on the estimated result. What is necessary is just to determine the opening time of the.

FIG. 4 is a graph showing a comparison result of the blast temperature during heating in the first embodiment and the conventional example. As is clear from this graph, according to the vehicle air conditioner according to the first embodiment, it is possible to quickly increase the blast temperature in the initial stage of heating start.

In addition, by using the heat pump cycle capable of absorbing heat from the engine cooling water as described above, the blowing temperature can be increased by the heat exchanger 15 having a larger capacity than the heater core 11. For this reason,
It is possible to supply air at a desired temperature into the vehicle while securing a desired air flow rate. Moreover, if the temperature of the engine cooling water becomes high (70 ° C. or more in the present embodiment), the auxiliary heat exchanger 12
Since the flow of water to the heat exchange medium is shut off, the heat exchange medium in the heat pump cycle does not become abnormally high in pressure due to the heat exchange medium being heated more than necessary.

In the case of cooling, that is, when an air conditioner (A / C) switch (not shown) is operated, the four-way valve 16
Switches as shown by the dotted line, and a so-called refrigeration cycle is formed. Then, the heat exchange medium discharged from the compressor 13 returns to the compressor 13 from the auxiliary heat exchanger 12, the outside heat exchanger 14, the expansion means 21, the inside heat exchanger 15, and the accumulator 18 and circulates. The heat exchange medium is a high-temperature, high-pressure gas state in the auxiliary heat exchanger 12.
Pass through. At this time, the temperature of the engine cooling water is 70 ° C.
If it is less than 3, the engine cooling water passes through the auxiliary heat exchanger 12 by the third solenoid on-off valve 27 as described above.
Heat can be released from the heat exchange medium to the engine cooling water. In addition, the heat exchange medium is also radiated to the outside air in the vehicle-side heat exchanger 14. Therefore, the pressure is reduced by passing through the expansion means 21, the amount of the heat exchange medium vaporized in the in-vehicle heat exchanger 15 increases, and the air passing through the blower unit 25 can be effectively cooled.

FIG. 5 is a graph showing a comparison result of the air blowing temperature at the time of cooling between the first embodiment and the conventional example. As is clear from this graph, according to the vehicle air conditioner according to the first embodiment, it is possible to rapidly lower the blast temperature in the initial stage of cooling start.

[0040]

As is apparent from the above description, according to the vehicle air conditioner of the present invention, the auxiliary heat exchange for exchanging heat between the engine cooling water and the heat exchange medium flowing in the heat exchange medium flow path. Since the heat exchanger is provided, the heating of the heat exchange medium during heating and the cooling of the heat exchange medium during cooling can be effectively performed, and the effect of the rapid effect of cooling and heating is exhibited.
In particular, since the oil cooler is provided in the cooling water bypass passage, the waste heat of the oil can also be used for heating the engine cooling water, and the rapid effect of heating can be further improved.

Further, when the viscosity of the oil is high, the flow rate in the oil cooler is suppressed by the oil bypass means, so that poor engine lubrication due to insufficient oil circulation due to an increase in flow resistance can be prevented.

Since the flow rate to the auxiliary heat exchanger is adjusted based on the pressure detected by the pressure detecting means, the temperature rise of the heat exchange medium is suppressed, and the suction and discharge pressures of the compressor are adjusted. Stopping can be prevented.

Further, based on the change in the heating capacity of the heat exchanger inside the vehicle and the change in the temperature of the engine cooling water, the flow rate to the heater core is adjusted so that the blown air temperature does not fluctuate greatly. If it is determined that the desired heating capacity can be obtained in the heater core based on the detected temperature, the driving of the compressor is stopped, so that the inside heat accompanying the engine load increase smoothly while maintaining the desired blowing temperature. It is possible to shift from heating the exchanger to heating the heater core.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a blower unit in which the vehicle interior heat exchanger and the heater core of FIG. 1 are disposed.

FIG. 3 is a graph showing changes in parameters.

FIG. 4 is a graph showing a comparison between the air-conditioning temperature of the vehicle air conditioner of FIG. 1 and that of a conventional example.

5 is a graph comparing the air-conditioning temperature during cooling between the vehicle air conditioner in FIG. 1 and the conventional air conditioner.

FIG. 6 is a schematic diagram of a vehicle air conditioner according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Heater core 12 ... Auxiliary heat exchanger 13 ... Compressor 14 ... Outside heat exchanger 15 ... Inside heat exchanger 20 ... Pressure detection sensor (pressure detection means) 23 ... Engine 24 ... Radiator 26 ... 2nd electromagnetic on-off valve ( Second flow rate adjusting means) 27 third electromagnetic on-off valve (flow rate adjusting means) 40 oil cooler 41 water temperature detecting sensor (water temperature detecting means) 42 water path switching member (oil bypass means) a heat exchange medium flow path b2: bypass passage for second cooling water b3 ... bypass passage for first cooling water b4 ... bypass passage for second cooling water b5 ... oil passage b6 ... oil bypass passage

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[Procedure amendment]

[Submission date] February 24, 1999 (Feb.
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Reference numeral 21 denotes a means for expanding the heat exchange medium, which may employ any method such as a capillary tube, a temperature expansion valve, an electric expansion valve, etc., so that the heat exchange medium passing therethrough is easily vaporized. Reference numeral 22 denotes an accumulator for gas-liquid separation.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

In the case of heating, that is, when a heat pump switch (not shown) is operated, the four-way valve 16 switches as shown by a solid line, and a so-called heat pump cycle is formed. At this time, the first electromagnetic on-off valve 17 prevents the heat exchange medium from flowing into the vehicle-side heat exchanger 14.
As a result, the heat exchange medium discharged from the compressor 13 returns to the compressor 13 from the in-vehicle heat exchanger 15, the expansion means 21, the auxiliary heat exchanger 12, and the accumulator 18 and circulates. In this case, the flow resistance increases due to the heat exchange medium passing through the auxiliary heat exchanger 12, but the heat exchange medium causes the heat exchange medium to pass through the vehicle-side heat exchanger 14 due to the closing operation of the first solenoid on-off valve 17. Since there is no circulation, the load on the compressor 13 does not increase. The heat exchange medium is made high temperature and high pressure by the compressor 13 and flows into the vehicle interior heat exchanger 15 to heat the air passing through the blower unit 25. Then, the auxiliary heat exchanger 12 absorbs heat from the engine cooling water. Therefore, the heat exchange medium returns to the compressor 13 with the heat capacity increased. For this reason,
In the present embodiment, the discharge pressure of the compressor 13 can be set to about 2.6 MPa and the condensing temperature can be set to about 80 ° C., so that a very high heating capacity can be exhibited.

Claims (4)

[Claims] 1. A cooling / heating cycle having a compressor, a vehicle exterior heat exchanger and a vehicle interior heat exchanger in a heat exchange medium channel, and a heater core provided in a heater core channel connected in parallel to a radiator channel having a radiator. An air cooler for cooling engine oil upstream of the heater core in the heater core flow path, a heater core bypass flow path is connected in parallel with the heater core, and the heat exchange medium flow path An air conditioner for a vehicle, comprising an auxiliary heat exchanger for exchanging heat between a flowing heat exchange medium and engine coolant flowing through the heater core bypass flow path. 2. An oil cooler bypass flow path is connected in parallel with the oil cooler, and oil bypass means for diverting the oil to the oil cooler bypass flow path when a desired viscosity is not obtained in the oil is provided. The vehicle air conditioner according to claim 1, wherein: 3. A flow rate adjusting means for adjusting a flow rate of the engine cooling water to the auxiliary heat exchanger; a pressure detecting means for detecting a discharge pressure of a heat exchange medium from the compressor; and the compressor satisfies a driving condition. Whether or not
A control means for judging based on the pressure detected by the pressure detecting means and adjusting the flow rate to the auxiliary heat exchanger by the flow rate adjusting means so as to satisfy the driving condition is provided. Item 3. The vehicle air conditioner according to item 1 or 2. 4. A radiator bypass flow path is connected in parallel with the radiator flow path, and a water temperature detecting means for detecting a temperature of engine cooling water is provided in the radiator bypass flow path, and a flow rate to the heater core is adjusted. 2, the control means estimates the heating capacity of the heat exchanger inside the vehicle based on the pressure detected by the pressure detection means, and based on the estimation result and a change in the engine coolant temperature. After adjusting the flow rate to the heater core so that the blowing temperature does not fluctuate significantly, if it is determined that the desired heating capacity can be obtained in the heater core based on the temperature detected by the water temperature detecting means, the driving of the compressor is stopped. The vehicle air conditioner according to claim 3, wherein: