KR20060069553A - Heat pump system for vehicle - Google Patents

Abstract

The present invention discloses a heat pump system for a vehicle.

The vehicle heat pump system according to the present invention includes a compressor, an outdoor gas cooler, an indoor gas cooler, a three-way valve that regulates the flow direction of the refrigerant, a shutoff valve that blocks backflow of the refrigerant, an internal heat exchanger, an throttling valve, an indoor evaporator, And an outdoor evaporator and configured to selectively perform a cooling mode and a heating mode, wherein the refrigerant is carbon dioxide, and a heating means 122 for heating the refrigerant on the low pressure side of the internal heat exchanger 112. ) Is provided.

Description

Heat pump system for vehicle

1 is a schematic diagram showing the overall structure of a conventional heat pump system.

Figure 2 is a schematic diagram showing the overall structure of a vehicle heat pump system according to a preferred embodiment of the present invention.

3 is a block diagram schematically illustrating a control relationship of the vehicle heat pump system of FIG. 2.

4 is a schematic diagram showing an operating state of the cooling mode of the vehicular heat pump system of FIG. 2.

FIG. 5 is a schematic diagram illustrating an operating state of a heating mode of the vehicle heat pump system of FIG. 2.

6 is a schematic diagram showing an operating state of the dehumidification heating mode of the vehicle heat pump system of FIG. 2.

<Brief description of symbols for the main parts of the drawings>

102: compressor 104: three-way valve

106: indoor gas cooler 108: shutoff valve

110: outdoor gas cooler 112: internal heat exchanger

114: throttling valve 116: three-way valve                 

118: outdoor evaporator 120: shutoff valve

122: heating means 124: indoor evaporator

The present invention relates to a heat pump system for a vehicle, and more particularly, to a heat pump system mounted on a vehicle to selectively perform cooling and heating functions.

In general, a vehicle heat pump system can selectively perform heating and cooling functions by operating a switch.

1 shows a schematic structural diagram of a conventional heat pump system. The vehicle heat pump type air conditioner is provided with an air conditioner unit 10, an evaporator 11, a mix damper 12, and a sub condenser 13 provided in an indoor panel (not shown). Then, the three-way valve 14 is operated to circulate the heating cycle discharged from the compressor 15 by the heating cycle indicated by the solid arrows (H) to perform dehumidification heating, and the cooling cycle indicated by the dotted arrows (C) is performed. It cools by circulating.

At the time of dehumidification heating, the high temperature and high pressure heat exchange medium discharged from the compressor 15 flows into the evaporator 11 through the bypass passage 16, the sub condenser 13, and the expansion valve 17, It is a structure that flows back into the compressor 15 and circulates. That is, since the heat exchange medium does not pass through the main condenser 18, the heating capacity is improved by the sub condenser 13.

At the time of heating, the high temperature and high pressure heat exchange medium discharged from the compressor 15 passes through the main condenser 18, the sub condenser 13, and the expansion valve 17, flows into the evaporator 11, and then the compressor again. It is a structure that flows into (15) and circulates. That is, the cooling capacity in the evaporator 11 is improved by radiating heat with the main condenser 18. FIG.

The outside air or the inside air introduced into the air conditioning unit 10 is cooled and dehumidified by the evaporator 11, classified into the mix damper 12, and maintained on the one hand as it is, and on the other hand, the sub-condenser ( 13) After heating with a mixture of both and blowing in the interior of the vehicle.

However, in the conventional conventional heat pump system, when one evaporator, which is a heat exchanger, is used in a room, the condensed water contained in the indoor heat exchanger is rapidly evaporated to humidify the inside of the vehicle when switching from the cooling mode to the heating mode. This could lead to frost and obstruct the driver's vision, resulting in an accident.

In addition, in the general heat pump system, when the outside air temperature is low during the heating mode operation, there is a problem in that the liquid refrigerant flows into the compressor and damages the compressor due to insufficient evaporation from the outdoor heat exchanger.

An object of the present invention is to solve the problems of the prior art as described above, to suppress the occurrence of frost that can occur when switching from the cooling mode to the heating mode, the heat exchanger freezes during the heating mode is not enough heat exchange It is to provide a vehicle heat pump system that can solve the problem that the liquid refrigerant flows into the compressor.

In order to achieve the above object, the vehicle heat pump system according to an embodiment of the present invention, the compressor 102, the outdoor gas cooler 110, the indoor gas cooler 106, three ways to adjust the flow direction of the refrigerant Cooling including valves 104 and 116, shutoff valves 108 and 120 to block backflow of refrigerant, internal heat exchanger 112, throttling valve 114, indoor evaporator 124, and outdoor evaporator 118 It is configured to selectively perform the mode and the heating mode, wherein the refrigerant is carbon dioxide vehicle heat pump system, characterized in that the heating means 122 for heating the refrigerant on the low pressure side of the internal heat exchanger (112) is provided. do.

Here, the heating means heats the low pressure side refrigerant in a heating heating mode operating under a low outside temperature and a dehumidifying heating mode in which heating is performed while removing moisture.

The internal heat exchanger also includes an accumulator for storing the refrigerant on the low pressure side.

On the other hand, the heating means is an electric heater.

Here, the outdoor evaporator heat exchanges with the cooling water of the engine of the vehicle.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.                     

Figure 2 is a schematic diagram showing the overall structure of a vehicle heat pump system according to a preferred embodiment of the present invention. On the other hand, the heat exchange medium is referred to herein as a refrigerant.

Referring to FIG. 2, the vehicle heater pump system of the present invention may be any one of the compressor 102, the outdoor gas cooler 110, the indoor gas cooler 106, the indoor gas cooler 106, and the outdoor gas cooler 110. A three-way valve 104 installed on the discharge side of the compressor 102 to selectively regulate the refrigerant flow of the compressor 102, and shutoff valves 108 and 120 that allow the refrigerant to flow in a predetermined flow direction and prevent it from flowing in the opposite direction , An internal heat exchanger 112 for performing heat exchange between the high pressure refrigerant and the low pressure refrigerant, an throttling valve 114 for reducing the pressure of the refrigerant, an indoor evaporator 124 for absorbing heat inside the vehicle, and heat outside the vehicle. It includes an outdoor evaporator 118 to absorb the evaporation of the refrigerant.

On the discharge side of the outdoor evaporator 118, a shutoff valve 120 is also installed to prevent backflow of the refrigerant, and the throttling valve to selectively control the flow to any one of the indoor evaporator 124 and the outdoor evaporator 118. The three-way valve 116 is attached to the discharge side of the 114. Furthermore, the heating means 122 for heating the refrigerant is mounted on the low pressure side refrigerant line of the internal heat exchanger, in which the refrigerant passes through the throttling valve 114 and the pressure drops, and then enters the internal heat exchanger 112 again.

Although not indicated by reference numerals in the drawings, each of the above-mentioned components is connected to a refrigerant line through which the refrigerant flows, and the refrigerant flowing through the refrigerant line is preferably carbon dioxide suitable for a supercritical cycle. It is not limited.                     

The refrigerant compressed and discharged by the compressor 102 is determined to flow from the three-way valve 104 installed on the discharge side of the compressor 102 to the external gas cooler 110 or to the internal gas cooler 106. It is done. Since the structure of the three-way valve is already disclosed technology, it will not be described separately herein.

According to FIG. 2, when the refrigerant compressed in the compressor 102 reaches the three-way valve 104 along the refrigerant line, the refrigerant line is bifurcated in the three-way valve 104 installed on the discharge side of the compressor 102. The path is forked. An indoor gas cooler 106 is installed at one side path, and a shutoff valve 108 for preventing backflow is installed at the refrigerant line at the discharge side of the indoor gas cooler 106.

On the other hand, the refrigerant line on the other path branched from the three-way valve 104 is equipped with an outdoor gas cooler 110, the refrigerant line along the path of the discharge-side shut-off valve 108 of the indoor gas cooler 106 and the The refrigerant line through which the refrigerant passing through the outdoor gas cooler 110 flows is recombined. After the refrigerant is compressed by the compressor 102 and the pressure of the refrigerant is high, the high-pressure side refrigerant line after the path passing through the indoor gas cooler 106 and the path passing through the outdoor gas cooler 110 is combined to generate an internal heat exchanger. While passing through the heat exchange with the low pressure side refrigerant line to be described later.

The refrigerant line through which the refrigerant that has undergone heat exchange in the internal heat exchanger 112 flows is connected to an throttling valve 114 which lowers the pressure of the refrigerant from high pressure to low pressure, and the discharge unit of the throttling valve 114 has the aforementioned compressor 102. Is provided with a three-way valve 116 separate from the three-way valve 104 provided on the discharge side. In the three-way valve 116 installed on the discharge side of the throttle valve 114, the refrigerant line is divided into a path through which the outdoor evaporator 118 passes and a path through the indoor evaporator 124.

The path branched from the three-way valve 116 to the outdoor evaporator 118 is provided with an outdoor evaporator 118 that exchanges heat with the engine ENG, followed by a shutoff valve 120 for preventing a backflow of the refrigerant. Subsequently, the throttling valve 114 is connected to the low pressure side refrigerant line of the internal heat exchanger 112 while maintaining a low pressure of the refrigerant. The path of the refrigerant line branched from the three-way valve 116 to the indoor evaporator 124 at the discharge side of the throttle valve 114 is connected to the internal heat exchanger 112 via the indoor evaporator 124.

On the other hand, in the internal heat exchanger (112), the heating means 122 is mounted on the inlet line of the refrigerant introduced after the pressure drops through the throttling valve (114), that is, the low pressure side refrigerant line. In addition, the internal heat exchanger 112 itself may serve as an accumulator to temporarily store the refrigerant in the low pressure side refrigerant line.

As can be seen from the above structure, the three-way valve 104 provided on the discharge side of the compressor 102 and the three-way valve 116 provided on the discharge side of the throttling valve 114 respectively have two paths of refrigerant lines. It has a structure that branches and merges again. The reason why the flow path of the refrigerant is adjusted in the three-way valves 104 and 116 is that the thermodynamic effects appearing in the respective paths are different. By regulating the flow path of the refrigerant in the three-way valves 104 and 116, the heat pump system exhibits the proper cooling or heating performance desired by the user of the vehicle.                     

By operating the three-way valve 104 provided on the discharge side of the compressor 102 and the three-way valve 116 provided on the discharge side of the throttle valve 114, the vehicle heat pump system according to the embodiment of the present invention has the following four types. Can provide a heating and cooling mode.

For example, the cooling and heating modes include a cooling mode that cools the inside of the vehicle and a heating mode that warms the inside of the vehicle. In particular, in the heating mode, when the outside air temperature of the vehicle is relatively high compared to a predetermined temperature, for example, when the outside air temperature of the vehicle is relatively low compared to the predetermined temperature, for example, when the outside air temperature of the vehicle is relatively low compared to the predetermined temperature, for example, There is a heating heating mode operating in the case and a dehumidifying heating mode in which heating is performed while removing moisture generated inside the vehicle.

In general, the standard heating mode is a mode in which the outside temperature is relatively low in heating the interior of a vehicle including a cab and a cabin for driving a vehicle, that is, in early winter or early spring, and the heating heating mode is cold The heating mode is used to heat the inside of the car.

These various types of cooling and heating modes control the three-way valve 104 on the compressor discharge side and the three-way valve 116 on the throttle valve discharge side to control the flow direction of the refrigerant by the predetermined indoor / outdoor gas coolers 106 and 110 and the indoor / outdoor evaporator 124. 118). Therefore, in the vehicle heat pump system of the present invention, the overall cooling and heating mode is selected by the control of the three-way valves 104 and 116.

3 is a block diagram schematically illustrating a control relationship of the vehicle heat pump system of FIG. 2.                     

Referring to FIG. 3, a control signal is transmitted to a control unit 132 of an air conditioning system of a vehicle by a user of the vehicle operating a control switch 130 for controlling an air conditioning apparatus installed in a control panel inside a cab of a vehicle. The controller 132 controls the three-way valve 104 installed on the compressor discharge side and the three-way valve 116 provided on the throttle valve discharge side to control the flow direction of the refrigerant. In addition, the control unit 116 may be electrically connected to the heating means installed in the low pressure side refrigerant line of the internal heat exchanger 112 to control the heating means.

Therefore, when the user of the vehicle operates the control switch 130, in response to the control unit 132 to operate or stop the three-way valve (104, 116) or the heating means 122 in accordance with the operation signal. can do.

4 to 6 are schematic diagrams showing the operating states of the vehicle heat pump system of the present invention according to each cooling and heating mode. 4 to 6 are diagrams illustrating paths through which refrigerant flows in the heat pump system shown in the schematic diagram of FIG. 2 for each mode. 4 to 6, the coolant line through which the actual coolant flows is indicated by a thick solid line, and the flow direction of the coolant is indicated by an arrow.

4 is a view showing a flow path of the refrigerant in the cooling mode of the vehicle heat pump system of the present invention.

Referring to FIG. 4, the refrigerant compressed at high pressure in the compressor 102 flows along a refrigerant line to a three-way valve 104 installed at the compressor discharge side. Here, the three-way valve 104 flows the refrigerant to the outdoor gas cooler 110 by the operation of the control unit. The refrigerant condensed in the outdoor gas cooler 110 performs heat exchange with the low pressure side refrigerant line while passing through the internal heat exchanger 112 along the high pressure side refrigerant line.

As the refrigerant passing through the internal heat exchanger passes through the throttling valve 114, the pressure decreases, and the refrigerant flows from the low pressure side refrigerant line therefrom. The three-way valve 116 mounted on the discharge side of the throttle valve 114 flows the refrigerant to the indoor evaporator 124 inside the vehicle according to the control signal of the controller 132, and heats the interior of the vehicle from the indoor evaporator 124. Will absorb.

The refrigerant passing through the indoor evaporator 124 flows along the low pressure side refrigerant line of the internal heat exchanger 112 and is returned to the compressor 102 to complete one cooling cycle. The refrigerant returned to the compressor again exhibits a cooling effect by repeating circulation along the refrigerant line.

5 shows the flow path of the refrigerant in the standard heating mode and the heating heating mode.

Referring to FIG. 5, the refrigerant compressed at high pressure in the compressor 102 flows along a refrigerant line to a three-way valve 104 installed at the compressor discharge side. Here, the three-way valve 104 causes the refrigerant to flow to the indoor gas cooler 106 side, unlike the cooling mode in FIG. 4, by the operation of the control unit. Through the heat exchange in the indoor gas cooler 106, the refrigerant supplies warm air to the vehicle interior. Meanwhile, the refrigerant passing through the indoor gas cooler 106 passes through the shutoff valve 108 for preventing backflow and passes through the internal heat exchanger 112 along the high pressure side refrigerant line to perform heat exchange with the low pressure side refrigerant line. .                     

The high pressure refrigerant that exchanges heat with the refrigerant of the low pressure side refrigerant line through the internal heat exchanger 112 passes through the throttling valve 114, and the pressure decreases so that the refrigerant flows along the low pressure side refrigerant line from here. The three-way valve 116 mounted on the discharge side of the throttle valve 114 flows the refrigerant to the outdoor evaporator 118 outside the vehicle driver's seat according to the control signal of the controller 132, and the refrigerant flows from the outdoor evaporator 118 to the vehicle. Absorbs heat from outside of the engine ENG.

The refrigerant passing through the outdoor evaporator 118 passes through the shutoff valve 120 to prevent backflow, flows along the low pressure side refrigerant line of the internal heat exchanger 112, and is returned to the compressor 102 to return to one standard heating cycle. This is done. The refrigerant returned to the compressor repeats the circulation and exhibits a heating effect.

The standard heating mode is a heating mode used when the outside air temperature is relatively high, and when the outside air temperature is 0 ° C. or higher, a sufficient amount of heat can be absorbed by the outdoor evaporator, thereby ensuring sufficient heating performance.

On the other hand, when the outside air temperature is relatively low, the heating heating mode is used, even in this case, the flow path of the refrigerant is the same as the standard heating mode described above. That is, the refrigerant is the compressor 102, the three-way valve 104, the indoor gas cooler 106, the shutoff valve 108, the internal heat exchanger 112, the throttle valve 114, the three-way valve 116, outdoor It flows along the evaporator 118, the shutoff valve 120, and the internal heat exchanger 112.

However, when the outside air temperature is relatively low, the control unit 132 (FIG. 3) controls the heating unit 122 to heat the refrigerant so that the refrigerant flowing into the internal heat exchanger via the outdoor evaporator 118 is internal heat exchanged. Heated prior to heat exchange in group 112. By the operation of the heating means, even when the outside air temperature is relatively low, the air warmed to a temperature desired by the user of the vehicle is supplied to the vehicle interior. Preferably, the heating means 122 may be an electric heater.

On the other hand, when the outside air temperature is relatively low, the condensate is frozen in the outdoor evaporator 118 may be a case that the heat transfer is limited. The outdoor evaporator 118 may exchange heat with the coolant (not shown) of the vehicle engine to prevent such condensation and to secure a sufficient heat source.

In the cooling mode, the three-way valve 104 on the discharge side of the compressor operates to flow the refrigerant to the outdoor gas cooler 110 in the high pressure refrigerant line, and the refrigerant flows to the indoor evaporator 124 in the low pressure refrigerant line. The three-way valve 116 on the discharge side of the throttle valve is operated. In contrast, in the heating mode, the refrigerant flows to the indoor gas cooler 106 in the high pressure side refrigerant line, and the refrigerant flows to the outdoor evaporator 118 in the low pressure side refrigerant line.

As shown in FIG. 6, as another form of heating mode, a dehumidification heating mode is used in which heating is performed while removing moisture in a vehicle interior. In this case, the path of the high-pressure side refrigerant line of the refrigerant is also described in the above-described standard heating mode. Or the same as heating heating mode. That is, the refrigerant passes through the compressor 102, the three-way valve 104, the indoor gas cooler 106, the shutoff valve 108, the internal heat exchanger 112, and the throttling valve 114, It flows into the low pressure refrigerant line.                     

In the low pressure side refrigerant line, the refrigerant flows along the refrigerant flow path of the cooling mode described above. That is, in the low pressure side refrigerant line, the refrigerant flows along the three-way valve 116, the indoor evaporator 124, and the internal heat exchanger 112.

In other words, the dehumidification heating mode follows the path of the high pressure side refrigerant flow in the general heating mode, and the low pressure side refrigerant flow follows the path of the cooling mode.

When the heating capacity is required even in the dehumidifying heating mode, the control unit 132 (FIG. 3) controls the heating unit 122 to perform an operation of applying heat to the refrigerant, thereby passing the internal heat exchanger 112 through the indoor evaporator 124. The refrigerant flowing into the c) is heated by the heating means 122 prior to the heat exchange in the internal heat exchanger 112.

According to the vehicle heat pump system according to the embodiment of the present invention as described above, it is possible to prevent the generation of frost generated due to a sudden mode change when switching from the cooling mode to the heating mode in the existing heat pump system. In particular, when there is one indoor heat exchanger, the condensed water accumulated when switching from the cooling mode to the heating mode may be evaporated to provide excessive moisture to the interior of the vehicle and to prevent the occurrence of fog. This is because, in the present invention, the evaporator in which the condensed water is present is not heated, so there is no evaporation of the condensed water.

In addition, according to the present invention, since a process of heating to a predetermined temperature is performed before the refrigerant is introduced into the compressor 102 by the heating means 122 when the heating mode is operated at a low temperature, the outdoor heat exchanger freezes so that the heat exchange is not sufficient and the refrigerant is in a liquid phase. Even though the outdoor evaporator exchanges heat with the cooling water of the engine, and the refrigerant is secondarily heated in the heating means to change into the gas phase, such a problem that the refrigerant entering the compressor is in liquid phase and damages the compressor can be eliminated.

According to the heat pump system of the present invention having the configuration as described above, the following effects are expected.

First, it is possible to significantly suppress the occurrence of frost in the vehicle interior when switching from the cooling mode to the heating mode.

Second, it is possible to prevent the liquid refrigerant from entering the compressor when the heating mode is operated at low temperatures.

Third, it is operated in a configuration that can maximize the performance when operating the cooling mode and heating mode to maximize the cooling and heating performance of the system.

Fourth, it is possible to protect the compressor to enable a stable system operation improves the durability of the heat pump system.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

Cooling modes and heating, including compressors, outdoor gas coolers, indoor gas coolers, three-way valves to control the flow direction of refrigerant, shut-off valves to block backflow of refrigerant, internal heat exchangers, throttle valves, indoor evaporators, and outdoor evaporators In the vehicle heat pump system is configured to selectively perform the mode, wherein the refrigerant is carbon dioxide, And a heating means for heating the refrigerant on the low pressure side of the internal heat exchanger. The method of claim 1, And said heating means heats said low pressure side refrigerant in a heating heating mode operating at a low outside temperature and a dehumidifying heating mode in which heating is performed while removing moisture. The method of claim 1, The internal heat exchanger includes an accumulator for storing a refrigerant on the low pressure side. The method of claim 1, The heating means is a vehicle heat pump system, characterized in that the electric heater. The method of claim 1, And the outdoor evaporator exchanges heat with the coolant of the engine of the vehicle.

Images