JP2735627B2 - Automotive cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention comprises a high-pressure unit composed of a compressor and an air-cooled condenser, such as a vehicle-mounted refrigerator that can be mounted on a passenger car, and an evaporator. The present invention relates to an in-vehicle cooling device in which low-pressure units are provided separately from each other (for example, in a trunk room and a passenger seat) and both units are connected via a refrigerant pipe.

[Conventional technology]

FIG. 4 is an explanatory view showing an example of the configuration of a conventional in-vehicle refrigerator. In the figure, reference numeral 1 denotes a high-pressure unit, and 2 denotes a low-pressure unit, which are provided, for example, separately in a trunk room and a passenger seat, and a refrigerant (not shown) is provided between the two units 1 and 2 via a refrigerant pipe 3. It is connected so that it can circulate in the direction. First, the high-pressure unit 1 is configured by connecting components such as a compressor 11, a condenser 12, and a strainer 13 in series. The condenser 12 is, for example, a refrigerant pipe formed in a 99-fold form.
Usually, a large number of cooling fins 12b are interposed on the cooling fins 12b, and the cooling fins 12b are formed so as to allow an airflow from a cooling fan (not shown) to flow between the cooling fins 12b. Next, the low-pressure unit 2 is placed in a cabinet 21 provided with a heat insulating material.
22. The evaporator 22 is often of a fin tube type, for example, in order to increase the heat transfer area similarly to the condenser 12. The refrigerant pipe 3 has a discharge pipe 31 and a capillary tube 32 for feeding a liquid refrigerant,
And a suction pipe 33 for feeding gaseous refrigerant. 34
Is a coupler, and 4 is a partition.

With the above configuration, first, the gaseous refrigerant is compressed by the compressor 11 to be in a high-temperature and high-pressure state and fed to the condenser 12, where it is condensed into a high-pressure liquid by heat exchange, and
The foreign matter is removed through the discharge pipe 31 and fed inside the discharge pipe 31.
Next, a certain pressure loss is given in the capillary tube 32, and by evaporating and evaporating in the evaporator 22, heat is taken from the cabinet 21 and the temperature in the cabinet 21 is lowered, so that it functions as a so-called refrigerator. it can. The gaseous refrigerant then returns to the compressor 11 via the suction pipe 33, is compressed again, and is circulated.

[Problems to be solved by the invention]

In the SCQT type cooling device as described above, since the discharge pipe 31 can be disposed along the suction pipe 33, the high-pressure unit 1 and the low-pressure unit 2 can be separated by at least 1 m or more. However, on the other hand, since the capillary tube 32 passes through the atmosphere in which the low-pressure unit 2 is provided, the condenser tube 32 may be exposed to a temperature Tc higher than the ambient temperature Tu of the condenser 12. In this case, Tc> Tu, and when the temperature difference between Tc and Tu exceeds a certain value, the refrigerant heated at equal pressure crosses the saturated liquid line on the Mollier diagram to be in a so-called two-phase mixed state. That is, there is a problem that a part of the liquid refrigerant evaporates and evaporates while maintaining a constant pressure state, and generates a so-called flash gas in the capillary tube 32. When such a flash gas is generated in the capillary tube 32, the discharge pipe 31 is closed, so that the supply of the refrigerant becomes impossible, which not only causes a significant decrease in cooling capacity but also stops the operation of the entire cooling device. The situation also develops, damaging the equipment components.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides an in-vehicle cooling device in which a high-pressure unit and a low-pressure unit are separated from each other to prevent generation of flash gas in a refrigerant pipe. The purpose is to provide.

[Means for solving the problem]

In order to achieve the above object, according to a first aspect of the present invention, a high-pressure unit including a compressor and an air-cooled condenser and a low-pressure unit including an evaporator are provided separately from each other. In a vehicle-mounted cooling device connected via a refrigerant pipe, a temperature detecting means is provided near the condenser and the refrigerant pipe, respectively.
Output means for comparing the electric signals from both of these temperature detecting means and outputting the result is provided, and this output means is electrically connected to a control circuit of a driving device of the cooling fan so that the refrigerant in the condenser is cooled. A technical measure was adopted to prevent cooling.

Next, in the second invention, a technical means of the first invention is that a condenser is provided with an electric heating means, and a control circuit of the electric heating means is electrically connected to the output means. Means were added.

(Operation)

With the above configuration, first, in the first aspect, even when the temperature near the refrigerant pipe changes, the operation is continued when the difference from the temperature near the condenser is equal to or less than a predetermined value, Only when the value exceeds a predetermined value, the cooling fan is stopped to prevent the cooling of the refrigerant in the condenser.

Next, in the second invention, in addition to the effect of the first invention, an effect of promptly recovering the temperature of the refrigerant in the condenser to a predetermined value can be expected.

〔Example〕

FIG. 1 is an electric circuit diagram showing a first embodiment of the present invention. In this figure, reference numeral 5 denotes a motor, which is provided so as to be able to drive a cooling fan (not shown) for flowing a cooling-like air flow through the condenser 12 shown in FIG. A temperature switch 7 electrically connects the motor 5 to the power supply 10. The temperature switch 7 is provided in the vicinity of the condenser 12 shown in FIG. 4 and is formed so that the contact is opened at a temperature of, for example, 15 ° C. or less. When R-12 is used as a refrigerant,
If the temperature near the condenser 12 drops below 15 ° C., it is known that there is a risk of generating a flash gas in the discharge pipe 31 and / or the capillary tube 32 shown in FIG. Set as above.

With the above configuration, during normal operation, the temperature switch 7 closes the contacts as shown in FIG. 1, so that the rotation of the motor 5 allows the cooling air flow to flow through the condenser 12 shown in FIG. To cool and condense the refrigerant. Then condenser 12
When the temperature in the vicinity of falls below 15 ° C., the contact of the temperature switch 7 shown in FIG. 1 is opened and the motor 5 is stopped. Thereby, the flow of the cooling airflow to the condenser 12 shown in FIG. 4 can be stopped, and the supercooling of the refrigerant in the condenser 12 can be prevented, and the discharge pipe 31 and / or the capillary tube 32 can be prevented.
This can prevent the generation of flash gas in the interior.

FIG. 2 (a) is an explanatory view of a main part showing a second embodiment of the present invention, and FIG. 2 (b) is a sectional view taken along the line AA in FIG. 2 (a). In both figures, the condenser 12 is formed by fixing a refrigerant pipe 12a to the surface of a cooling fin 12b. Arrows indicate the flow direction of the refrigerant (not shown). 8 is a heater, for example,
A wire made of an electric resistance material such as Ni-Cr alloy is
Arranged along 12a and electrically connected to a heating power supply 10 via a thermostat 9 provided near the condenser 12. The thermostat 9 is formed so as to close the contact at 15 ° C. or lower when, for example, R-12 is used as a refrigerant.
The heaters 8 may be provided on both sides of the cooling fin 12b.

With the above configuration, until the condition for generating a flash gas in the discharge pipe 31 and / or the capillary tube 32 in FIG. 4 is reached, the vicinity of the condenser 12 shown in FIGS. When the temperature drops, for example, below 15 ° C., the contacts of the thermostat 9 close. As a result, the heater 8 is activated by the heating power supply 10, and the refrigerant (not shown) is heated through the cooling fins 12b and the refrigerant pipe 12a, thereby preventing the supercooling of the refrigerant and the generation of flash gas accompanying the cooling. is there. By thus providing the heater 8 in the condenser 12, the cooling efficiency of the entire apparatus is slightly reduced, but the loss of the function of the entire apparatus due to generation of flash gas can be completely avoided.

FIG. 3 is an electric circuit diagram showing a third embodiment of the present invention. In FIG. 3, reference numeral 51 denotes a transistor.
Are connected in series with each other so that the output voltage of the comparator 6 is input as a base voltage. Reference numerals 71 and 72 denote thermistors having negative characteristics, respectively. The temperature Tu near the condenser 12 and the temperature Tc near the refrigerant pipe 3 in FIG.
Is arranged to be measurable. And these thermistors 71,7
The output of 2 is connected to the input of comparator 6.

According to the above configuration, in the normal state, the base power is applied to the transistor 51 by the output voltage of the comparator 6, so that the motor 5 operates to drive the cooling fan (not shown). A cooling air flow is passed through the condenser 12 shown in FIG. 3 to cool and condense the refrigerant, while the temperature Tu near the condenser 12 (see FIG. 4) detected by the thermistors 71 and 72 shown in FIG. Difference in temperature Tc near refrigerant pipe 3
When Tc-Tu exceeds, for example, 10 ° C., the output voltage of the comparator 6 in FIG.
The base voltage of 51 drops, and the motor 5 is stopped. This prevents overcooling of the refrigerant in the condenser 12 shown in FIG. 4 and prevents loss of the function of the cooling device due to generation of flash gas. When the temperature Tc near the refrigerant pipe 3 in FIG. 4 is substantially constant, there is no problem because the temperature Tu near the condenser 12 is also substantially constant. However, when the temperature Tc changes, especially when this temperature Tc changes. When Tc increases, the temperature Tu near the condenser 12 also increases, and the cooling fan may not stop. However, by configuring as shown in FIG. 3, the motor 5 can be stopped as described above. It is effective because it can.

In the second embodiment of the present invention, an example is shown in which a cooling fan is not provided in the condenser, but a cooling fan may be provided as in the other embodiments. In each of the above embodiments, the operation is the same even if an expansion valve is provided instead of the capillary tube. Although the case where the low-pressure unit is a refrigerator has been described, a small-sized freezer may be used. Alternatively, the low-pressure unit may be used as a cooling device for supplying cool air to a passenger seat.

〔The invention's effect〕

Since the present invention has the configuration and operation as described above, the following effects can be expected.

(1) The generation of flash gas due to supercooling of the refrigerant in the condenser constituting the high-pressure unit can be prevented, and the cooling device can be operated smoothly.

(2) Even if the temperature difference between the high-pressure unit and the low-pressure unit is large, generation of flash gas can be prevented.

(3) It is not necessary to provide a special complicated device for preventing the generation of flash gas, and the function of a small and light-weight on-board cooling device can be maintained.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the present invention, FIG. 2 (a) is an explanatory view of a main part showing a second embodiment of the present invention, and FIG. 2 (b) is a diagram of FIG. 3) is an AA sectional view, FIG. 3 is an electric circuit diagram showing a third embodiment of the present invention, and FIG. 4 is an explanatory diagram showing an example of the configuration of a conventional on-vehicle refrigerator. 1: High pressure unit, 2: Low pressure unit, 3: Refrigerant piping, 7; Temperature switch, 8: Heater, 9: Thermostat, 6: Comparator, 71, 72: Thermistor.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 63-194275 (JP, U) Japanese Utility Model Sho 51-63263 (JP, U) Japanese Utility Model Sho 56-36090 (JP, U) Japanese Utility Model Sho 55- 146984 (JP, U)

Claims (2)

(57) [Claims] A high-pressure unit comprising a compressor and an air-cooled condenser and a low-pressure unit comprising an evaporator are provided separately from each other, and both units are connected via a refrigerant pipe. In the cooling device, a temperature detecting means is provided near the condenser and the refrigerant pipe, and an output means for comparing the electric signals from the two temperature detecting means and outputting the result is provided, and the output means is driven by a cooling fan. An in-vehicle cooling device, which is electrically connected to a control circuit of the device and configured to prevent overcooling of a refrigerant in a condenser. 2. The on-vehicle cooling device according to claim 1, wherein an electric heating means is provided in the condenser, and a control circuit of the electric heating means is electrically connected to the output means.