JPH0445924Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a technology for improving the performance of a vehicle cooling system, particularly an evaporator.

(Prior Art) A conventional vehicle cooling system has the following basic components: a condenser that cools high-temperature, high-pressure refrigerant vapor into medium-temperature, high-pressure liquid refrigerant; a liquid tank that stores the medium-temperature, high-pressure liquid refrigerant; an expansion valve that rapidly expands a high-pressure liquid refrigerant into a low-temperature, low-pressure atomized refrigerant; an evaporator that removes heat from the outside by vaporizing the low-temperature, low-pressure atomized refrigerant; Some devices are known that are equipped with a compressor that compresses refrigerant vapor into high-temperature, high-pressure refrigerant vapor and returns it to the condenser.

In the expansion valve, the refrigerant flow rate is automatically adjusted in response to changes in heat load based on the refrigerant temperature on the evaporator outlet side detected by the temperature-sensitive cylinder, and the degree of superheating (superheat) in the evaporator is automatically adjusted. The position of the valve opening degree is set in advance so as to keep it constant.

In addition, the degree of superheat (superheat) refers to the temperature that has risen due to further heating from the saturated vapor state where the atomized refrigerant (saturated liquid) has completely evaporated in the evaporator to the exit of the evaporator. good,
This high degree of superheating means that evaporation (vaporization) is completed early in the middle of the evaporator, and in the remaining part, only saturated steam is heated and there is no vaporization effect, so the degree of superheating is low. The larger the value, the lower the capacity usage rate of the evaporator. Therefore, in order to make full use of the full capacity of the evaporator and enhance the cooling effect, this heating degree should be set to be as small as possible.

(Problem that the invention aims to solve) However, since the compressor rotation speed fluctuates largely in proportion to increases and decreases in the engine rotation speed, if the evaporator heating degree is set low, the engine speed will suddenly increase. Due to this increase, the amount of atomized refrigerant flowing into the evaporator increases rapidly, and liquid refrigerant that still has cooling capacity is returned to the compressor in what is called liquid back. There is a risk of damaging the valve.

For this reason, in conventional vehicle cooling systems, it is necessary to increase the degree of superheating of the evaporator (approximately 10 degrees), which means that the evaporator is used below its capacity by this degree of superheating.

(Means for solving the problem) The present invention was made with the purpose of solving the above-mentioned problems.To achieve this purpose, the present invention cools high temperature and high pressure refrigerant vapor to a medium temperature. a condenser that converts the medium temperature and high pressure liquid refrigerant into a high pressure liquid refrigerant; a liquid tank that stores the medium temperature and high pressure liquid refrigerant; a throttle valve that rapidly expands the medium temperature and high pressure liquid refrigerant to form a low temperature and low pressure mist refrigerant; and the low temperature and low pressure mist. A vehicle cooling system comprising: an evaporator that removes heat from the outside through the vaporization of refrigerant; and a compressor that compresses low-temperature, low-pressure refrigerant vapor from the evaporator into high-temperature, high-pressure refrigerant vapor; A refrigerant bypass line is provided between the inlet side of the evaporator and the outlet side of the evaporator, and the bypass line is provided with a heat exchanger and a heat exchanger throttle valve, and the evaporator throttle valve and the heat exchanger are equipped with a heat exchanger and a heat exchanger throttle valve. A flow rate regulating valve is used as a dexterous throttle valve, and superheat is controlled in the pipeline from the outlet side of the evaporator to the junction with the bypass pipeline, and in the pipeline from the heat exchanger outlet side to the compressor. temperature sensors are provided, and based on the input signals from the respective superheat degree sensors, the degree of superheat of the refrigerant on the evaporator outlet side is small;
A degree-of-superheat control circuit was provided to control each flow rate adjustment valve so that the degree of superheat of the refrigerant on the outlet side of the heat exchanger was increased.

(Function) Therefore, in the vehicle cooling system of the present invention, as described above, the fuel cooling heat exchanger is provided bypassing the evaporator, and the heat exchanger is provided at the evaporator outlet side based on the input signal from each superheat sensor. Equipped with a superheat degree control circuit that controls each flow rate adjustment valve so that the degree of superheat of the refrigerant is small and the degree of superheat of the refrigerant on the outlet side of the heat exchanger is large, making full use of the evaporator's capacity to achieve cooling effects. In addition, by merging the evaporator side refrigerant with a small degree of superheat and the heat exchanger side refrigerant with a high degree of superheat, the degree of superheat on the evaporator outlet side can be increased outside the evaporator. As a result, the phenomenon of liquid returning to the compressor (liquid back) can be prevented.

In addition, as mentioned above, by using a bypass heat exchanger for cooling the fuel as a means to increase the degree of superheating on the evaporator outlet side outside the evaporator, it becomes possible to cool the fuel at the same time without installing a separate cooling device. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
In describing this embodiment, an automobile cooling system will be taken as an example.

First, the configuration of the embodiment will be explained.

As shown in FIGS. 1 and 2, the automotive cooling device A of the embodiment includes a condenser 1, a liquid tank 2, an evaporator flow rate adjustment valve 3, an evaporator 4, a compressor 5, a bypass pipe line 6, and a fuel cooling heat source. The main components are an exchanger 7, a heat exchanger flow rate adjustment valve 8, superheat degree sensors 9 and 10, and a superheat degree control circuit 11.

The condenser 1 is disposed in front of the radiator, and is a condenser that cools high-temperature, high-pressure refrigerant vapor to a condensation point using wind obtained by the cooling fan 12 or vehicle speed to turn it into a medium-temperature, high-pressure liquid refrigerant. The side is connected to the outlet side of the compressor 5 by a conduit 13.

The liquid tank 2 is a liquid receiver that stores the medium temperature and high pressure liquid refrigerant, removes moisture and dust contained in the liquid refrigerant, separates vapor, and sends only the liquid refrigerant to the flow rate regulating valves 3 and 8. The inlet side thereof is connected to the outlet side of the condenser 1 through a conduit 14.

The evaporator flow rate regulating valve 3 is a means for rapidly expanding the medium-temperature, high-pressure liquid refrigerant condensed in the condenser 1 to turn it into a low-temperature, low-pressure atomized refrigerant, and controlling the refrigerant flow rate, and its inlet side is connected to the liquid tank. It is connected to the outlet side of No. 2 by a conduit 15.

The evaporator 4 is an evaporator that evaporates the low-temperature, low-pressure atomized refrigerant injected from the flow rate adjustment valve 3, and uses the heat of vaporization at that time to remove heat from the air inside the vehicle sent from the blower 16. It is connected to the outlet side of the flow rate regulating valve 3 through a conduit 17 .

The compressor 5 is a condenser that compresses the low-temperature, low-pressure refrigerant vapor evaporated in the evaporator 4 and returns it to the high-temperature, high-pressure refrigerant vapor to the condenser 1, and its inlet side is connected to the evaporator 4 through a pipe line 18. ing.

The bypass pipe line 6 is a pipe line that bypasses the evaporator flow rate adjustment valve 3 and the evaporator 4, and its branch point a is provided in the outlet side pipe line 15 of the liquid tank 2, and its confluence point b is located in the outlet side pipe line 15 of the liquid tank 2. It is provided in the outlet side conduit 18 of No. 4.

The fuel cooling heat exchanger 7 is a fuel cooling means installed in the bypass pipe line 6, and in this embodiment, as shown in FIG.
The evaporated fuel gas is condensed and liquefied by cooling it in the fuel evaporative gas flow path 71, and the liquefied fuel is collected into the fuel tank 70. It is constituted by a refrigerant flow passage 72 installed therein.

In this embodiment, the refrigerant flow passage 72 is arranged so as to surround the outer periphery of the fuel evaporative gas flow passage 71, and the fuel evaporative gas discharge side is connected to the refrigerant upstream side, and the fuel tank 70 is connected to the refrigerant downstream side. connected to the side.

Further, a liquefied fuel return pipe 73 is connected between the lowest part of the fuel gas flow path 71 and the fuel tank 70.

In the figure, 74 is a canister, which constitutes a fuel evaporative gas regulation device that is installed in the fuel evaporative gas flow path 71 to adsorb fuel evaporative gas and suppress air pollution. It is.

The heat exchanger flow rate adjustment valve 8 is a means for rapidly expanding the medium-temperature, high-pressure liquid refrigerant condensed in the condenser 1 to turn it into a low-temperature, low-pressure atomized refrigerant, and controlling the refrigerant flow rate. It is interposed in the bypass pipe line 6 between the fuel cooling heat exchanger 7 and the fuel cooling heat exchanger 7.

The superheat degree sensors 9 and 10 are sensors for measuring the temperature that has increased due to further heating from the time when the liquid refrigerant is completely evaporated, and are equipped with pressure measuring means and temperature measuring means. The evaporator superheat sensor 9 is installed in the conduit 18 between the outlet side of the evaporator 4 and the confluence b, and the heat exchanger superheat sensor 10 is installed in the fuel cooling heat exchanger 7.
In the bypass pipe line 6 between the outlet side of and the confluence b,
Alternatively, it is provided in the conduit 18 between the confluence point b and the compressor 5.

The superheat degree control circuit 11 controls the superheat degree of the refrigerant on the outlet side of the evaporator 4 to be small and the degree of superheat of the refrigerant on the outlet side of the heat exchanger to be large, based on the input signals of the superheat degree sensors 9 and 10. , are means for controlling the corresponding flow rate regulating valves 3 and 8, and in this embodiment, the degree of superheating of the refrigerant on the outlet side of the evaporator 4 is set to 0 degrees, and the degree of superheating of the refrigerant on the outlet side of the heat exchanger is set to 15 degrees. It is set to .

Next, the operation of the embodiment will be explained.

First, the basic operation of the automobile cooling device A will be explained separately for the liquid refrigerant system and the gas refrigerant system.

(a) Liquid refrigerant system First, the medium temperature and high pressure liquid refrigerant condensed in the condenser 1 is sent to the liquid tank 2 through the pipe 14, and water, dust, vapor, etc. are separated by passing through the liquid tank 2. The removed state is sent to the evaporator flow rate adjustment valve 3 through the pipe 15, and a part of it is diverted from the branch point a to the bypass line 6, and also sent to the heat exchanger flow rate adjustment valve 8.

The liquid refrigerant sent to the evaporator flow rate adjustment valve 3 is rapidly expanded at its outlet side by the throttling action of the flow rate adjustment valve 3, and becomes a low-temperature, low-pressure atomized (liquid) refrigerant that flows into the pipe. 17 and is sent to the evaporator 4.

The low-temperature, low-pressure atomized (liquid) refrigerant sent to the evaporator 4 evaporates due to the heat load inside the car, and the heat of vaporization at that time removes heat from the air inside the car sent from the blower 16, and the cold air is introduced into the car. By sending out the air, the inside of the car will be cooled.

The refrigerant vapor evaporated in the evaporator 4 is then sent to the compressor 5 through a pipe 18.

Further, as described above, some of the liquid refrigerant that is diverted from the diversion point a to the bypass pipe line 6 and sent to the flow rate adjustment valve 8 for the heat exchanger is transferred to its outlet side by the throttling action of the flow rate adjustment valve 8. The refrigerant is rapidly expanded, becomes a low-temperature, low-pressure atomized (liquid) refrigerant, and is sent to the refrigerant flow path 72 that constitutes the fuel cooling heat exchanger 7.

In the refrigerant flow path 72, the atomized refrigerant that has become low temperature and low pressure is evaporated by the heat of the fuel evaporative gas, and the fuel gas in the fuel evaporative gas flow path 71 is cooled by the heat of vaporization at that time. The liquefied fuel passes through the return pipe 73 to the fuel tank 70.
will be collected within.

If an amount of fuel evaporative gas is generated that exceeds the cooling capacity of the fuel cooling heat exchanger, the unliquefied fuel evaporative gas passes through the canister 74 and is turned into HC (hydrocarbon) by activated carbon.
will be released into the atmosphere in an adsorbed state.

(B) Gaseous Refrigerant System First, the low-temperature, low-pressure refrigerant vapor evaporated in the evaporator 4 and the refrigerant flow path 72 as described above is sent to the compressor 5 through the pipe line 18.

Next, in the compressor 5 , the low-temperature, low-pressure refrigerant vapor is compressed into high-temperature, high-pressure refrigerant vapor, and this high-temperature, high-pressure refrigerant vapor is sent to the condenser 1 through the pipe 13 .

In the condenser 1, the high-temperature, high-pressure refrigerant vapor is cooled to a condensation point by the cooling fan 12 and wind generated by the vehicle speed, and is returned to the liquid refrigerant system as a medium-temperature, high-pressure liquid refrigerant.

Next, the effects related to superheat degree control will be explained separately for when the vehicle is running at a constant speed and when the vehicle is rapidly accelerating.

(b) When running at a constant speed First, when the car is running at a constant speed, the rotation speed of the compressor 1 is stable, so the superheat degree control circuit 11 adjusts both flow rates to follow the fluctuations in the heat load. The opening degree of the valves 3 and 8 is controlled.

That is, when the heat load increases, the amount of refrigerant becomes insufficient and the degree of superheat increases. Therefore, the degree of superheat control circuit 11
The operation control signal c is sent to each flow rate regulating valve 3, 8 from
are outputted, and the flow rate regulating valves 3 and 8 are operated in the direction of opening according to the operation control signal c, thereby controlling the amount of refrigerant inflow to be increased and the degree of superheat to be lowered.

Contrary to the above, when the heat load decreases, the flow rate regulating valves 3 and 8 are operated in the direction of closing, thereby controlling the amount of refrigerant inflow to be reduced and the degree of superheat to be increased.

(b) During sudden acceleration Even if there is no variation in the heat load as described above, when the engine speed suddenly increases, such as when a car suddenly accelerates, the speed of the compressor 5 also increases rapidly, which causes the evaporator 4 and refrigerant flow path 72
The amount of refrigerant flowing into the interior of the interior of the engine rapidly increases, resulting in a sudden decrease in the degree of superheat, but in this case as well, the input signals from the respective superheat degree sensors 9 and 10 Based on t, the superheat degree control circuit 11 outputs an operation control signal c to each flow rate adjustment valve 3, 8, and this operation control signal c causes each flow rate adjustment valve 3, 8 to be closed. As a result, the amount of inflow of refrigerant is reduced and the degree of superheating is increased.

In addition, when the degree of superheat of the refrigerant on the outlet side of the evaporator 4 is set to 0 degrees as in this embodiment, the degree of superheat instantly drops to 0 degrees when the automobile suddenly accelerates as described above.
However, since the degree of superheating of the refrigerant on the outlet side of the fuel cooling heat exchanger 7 is set to a large 15 degrees, both refrigerants are By merging at the merging point b, a moderate degree of superheating of 0 degrees or higher is achieved, so that no liquid returns to the compressor 5 (liquid back).

As explained above, in the automobile cooling device A of this embodiment, as described above, the evaporator 4
A heat exchanger 7 for cooling the fuel is provided by bypassing the evaporator 4, and based on input signals t from each superheat degree sensor 9, 10, the degree of superheat of the refrigerant on the outlet side of the evaporator 4 is small, and the refrigerant on the outlet side of the heat exchanger is overheated. By providing a superheat degree control circuit 11 that controls each of the flow rate regulating valves 3 and 8 so that the temperature increases, it becomes possible to fully utilize the capacity of the evaporator 4 and enhance the cooling effect. By merging the refrigerant on the evaporator 4 side with a low degree of superheat and the refrigerant on the heat exchanger side with a high degree of superheat, the degree of superheat on the exit side of the evaporator 4 can be increased outside the evaporator 4. The liquid back phenomenon can be prevented.

Furthermore, as described above, by using the fuel cooling heat exchanger 7 that cools the fuel gas as a means for increasing the degree of superheating on the exit side of the evaporator 4 outside the evaporator 4, the fuel gas can be cooled without installing a separate cooling device. At the same time, cooling can prevent fuel from being released into the atmosphere.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, the example drawings show a case in which a superheat degree sensor for a heat exchanger is installed in a conduit from a confluence point to a compressor, but a bypass conduit from the outlet side of a fuel cooling heat exchanger to a confluence point is shown. It may be provided inside.

Further, in the embodiment, a case has been shown in which the fuel gas is cooled as a fuel cooling heat exchanger, but the heat exchanger is not limited to this, and may be used to cool the fuel itself, intake air, exhaust air, etc.

(Effects of the invention) As explained above, in the vehicle cooling system of the invention, as mentioned above, a heat exchanger for cooling the fuel is provided bypassing the evaporator, and input signals from each superheat degree sensor are provided. Equipped with a superheat degree control circuit that controls each flow rate adjustment valve so that the degree of superheat of the refrigerant on the evaporator outlet side is small and the degree of superheat of the refrigerant on the heat exchanger outlet side is high based on the In addition, by merging the evaporator side refrigerant with a low degree of superheat and the heat exchanger side refrigerant with a high degree of superheat,
Since the degree of superheating on the evaporator outlet side can be increased outside the evaporator, the phenomenon of liquid returning to the compressor can be prevented.

Furthermore, as mentioned above, by using a cooling heat exchanger as a means to increase the degree of superheating on the evaporator outlet side outside the evaporator, it becomes possible to cool the fuel at the same time without installing a separate cooling device. Effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing an automobile cooling system according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing details of a fuel cooling heat exchanger. 1...Capacitor, 2...Liquid tank, 3
...Flow control valve for evaporator, 4 ... Evaporator, 5 ... Compressor, 6 ... Bypass line, 7 ... Heat exchanger for fuel cooling, 8 ... Flow control valve for heat exchanger, 9 ... Degree of superheating Sensor, 10... Superheat degree sensor, 11... Superheat degree control circuit.

Claims (1)

[Claims for Utility Model Registration] A condenser that cools high-temperature, high-pressure refrigerant vapor into a medium-temperature, high-pressure liquid refrigerant; a rigid tank that stores the medium-temperature, high-pressure liquid refrigerant; and a device that rapidly expands the medium-temperature, high-pressure liquid refrigerant. an evaporator that removes heat from the outside by vaporizing the low-temperature, low-pressure atomized refrigerant; and an evaporator that compresses the low-temperature, low-pressure refrigerant vapor from the evaporator into high-temperature, high-pressure refrigerant vapor. In the vehicle cooling system, a refrigerant bypass line is provided between the inlet side of the evaporator throttle valve and the outlet side of the evaporator, and a heat exchanger is provided in the bypass line, and a heat exchanger is provided in the bypass line. A flow rate adjustment valve is used as the evaporator throttle valve and the heat exchanger throttle valve, and a flow rate adjustment valve is used as the evaporator throttle valve and the heat exchanger throttle valve. , a superheat sensor is provided in each pipe line from the heat exchanger outlet side to the compressor, and based on the input signal of each superheat sensor,
A vehicle cooling system comprising a superheat degree control circuit that controls each flow rate adjustment valve so that the degree of superheat of the refrigerant on the outlet side of the evaporator is small and the degree of superheat of the refrigerant on the outlet side of the heat exchanger is large.