JPH05157410A - Refrigerating plant for vehicle - Google Patents

Abstract

PURPOSE:To suppress the heat generation effectively even when an excessive electric current flows through a resistance heater because of locking the blower or other reasons by limiting the electric current supplied to a blower and providing a drain pan that receives the drain water falling from a refrigerant evaporator with a resistance heater to heat the drain pan. CONSTITUTION:In air conditioning operation the air in a refrigeration is being cooled by blowing the air to a refrigerant evaporator 10 by means of a plurality of cooling fans 15. If in this cooling the air is cooled below its dew point temperature by the evaporator 10, the moisture in the air condenses and water drops attach the surface of the evaporator 10, and those water drops flow down on to a drain pan 16 and they freeze there. When the temperature in the refrigerating chamber falls to a specified temperature, a relay switch is closed and the electric current is supplied to the fans 15 through a resistance heater 17, limiting thereby the rotation of the fans 15. And by the heat generation in the resistance heater 17 the drain pan 16 directly attached to the resistance heater 17 is heated and the ice feezing in the drain pan is thereby melted and discharged to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular refrigerating device which also serves as an air flow rate changing register of a blower and a drain pan heater.

[0002]

2. Description of the Related Art Conventionally, in a vehicle refrigeration system,
In order to prolong the life or reduce the noise of the blower that blows air to the refrigerant condenser of the refrigeration cycle, the resistor, which is a resistance heating element, limits the energizing current to the blower to adjust the air volume.

[0003]

However, in the conventional vehicle refrigeration system, when the blower is locked and an overcurrent flows through the register, the register remarkably generates heat. At this time, if the heat radiation performance of the register is poor, there is a problem that the temperature of the register is excessively increased. An object of the present invention is to provide a vehicular refrigeration system that suppresses excessive temperature rise of a resistance heating element.

[0004]

SUMMARY OF THE INVENTION The present invention provides a refrigeration cycle having a refrigerant evaporator for evaporating a refrigerant and a refrigerant condenser for condensing the refrigerant, and an air flow passing through the refrigerant evaporator or the refrigerant condenser. A blower to be generated, a drain pan that is arranged below the refrigerant evaporator and receives drain water that has dropped from the refrigerant evaporator, and a resistance heating element that limits the current supplied to the blower and heats the drain pan. The technical means provided were adopted.

[0005]

The present invention provides a low-temperature drain pan that receives drain water dropped from the refrigerant evaporator even if an overcurrent flows through the resistance heating element due to the blower locking or the like and the heat generation amount of the resistance heating element increases. Since the heat generated by the resistance heating element is quickly dissipated via this, excessive temperature rise of the resistance heating element can be suppressed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle refrigeration system of the present invention will be described based on an embodiment shown in FIGS. FIG. 1 is a diagram showing a cooling unit of an automobile refrigeration system to which an embodiment of the present invention is applied, and FIG. 2 is a diagram showing a refrigeration cycle of the automobile refrigeration system. The automobile refrigeration system 1 has a refrigeration cycle 2 and includes a cooling unit 4 for refrigerating or refrigerating the inside of a refrigerating chamber 3 that insulates the inside and the outside of the room. The refrigeration cycle 2 is discharged from the refrigerant compressor 5, the three-way switching valve 6, the refrigerant condenser 7, the liquid receiver 8, the expansion valve 9, the refrigerant evaporator 10, the accumulator 11, and the refrigerant compressor 5 during the defrosting operation. It is composed of a bypass line 12 for allowing a high-temperature and high-pressure refrigerant gas to directly flow into the refrigerant evaporator 10.

The three-way switching valve 6 connects the discharge part of the refrigerant compressor 5 and the refrigerant condenser 7 during the freezing operation, and connects the discharge part of the refrigerant compressor 5 and the bypass line 12 during the defrosting operation. To do. Moreover, the refrigerant condenser 7 heat-exchanges the inflowing refrigerant with the air outside the freezer compartment 3 blown by the condenser fan 13 to condense the refrigerant.

The cooling unit 4 includes the above-described refrigerant evaporator 10, a duct 14 for accommodating the refrigerant evaporator 10, a plurality of cooling fans 15 for blowing the air in the freezing compartment 3 to the refrigerant evaporator 10, a freezing operation or removal. The drain pan 16 receives drain water generated during frost operation, and two resistance heating elements 17 attached to the back surface of the drain pan 16.

The refrigerant evaporator 10 is fixed to the duct 14 by fasteners such as bolts and nuts. The refrigerant evaporator 10 exchanges heat between the inflowing refrigerant and the air in the freezer compartment 3 to evaporate the refrigerant and cool the air. The duct 14 is made of metal or resin and is composed of a plurality of duct components 18 to 20 and a fan shroud 21, which are connected by fasteners such as bolts and nuts, and are attached near the ceiling of the freezer compartment 3.

The plurality of cooling fans 15 are the blower of the present invention, and are fixed to the duct 14 via the stay 22 by fasteners such as bolts and nuts. These cooling fans 15 draw in the air in the freezer compartment 3 into the ducts 14 when the energizing current flows, so that the refrigerant evaporator 10 is cooled.
After that, the cold air cooled by the refrigerant evaporator 10 is blown into the freezer compartment 3. The cooling fan 15
Is connected to the vehicle power source 23 via a relay switch 24, as shown in FIG. Also, the cooling fan 15 rotates at high speed when the relay switch 25 is closed to obtain a large air volume (Hi mode), and the relay switch 2
When 5 is opened, the energization current is limited by the two resistance heating elements 17 to rotate at a low speed to obtain a small air volume (Lo mode).

The drain pan 16 is made of metal such as aluminum or resin and is fixed to the duct 14 by fasteners such as bolts and nuts so as to be located below the refrigerant evaporator 10. The drain pan 16 receives drain water falling from the refrigerant evaporator 10, and drains the drain water to the outside of the freezer compartment 3 through the drain pipe 26.

The two resistance heating elements 17 are the drain pan 16
Is directly attached to the back surface of the sheet with double-sided tape (not shown). These resistance heating elements 17 are PTs that keep the heating temperature constant due to the current limiting action in the region where the electric resistance changes suddenly.
It has a C-characteristic and has a flat plate shape so that the amount of heat per predetermined area of the drain pan 16 becomes uniform. The two resistance heating elements 17 are, as shown in FIG.
When the relay switch 25 is opened and the relay switch 25 is opened, it functions as an air flow rate variable register that limits the energizing current to the cooling fan 15. The two resistance heating elements 17 are
As shown in FIG. 3, when the relay switches 24 and 25 are opened and the relay switch 27 is closed, the drain pan 1
It works as a planar heater for heating 6. Further, the two resistance heating elements 17 are provided when the relay switch 25 is closed.
Energization stops.

The lower side of the two resistance heating elements 17 is
It is covered with two insulators 28 so that the heat of these resistance heating elements 17 is not radiated from the lower side. Further, the drain pan 16, the two resistance heating elements 17 and the two insulators 28 are covered with a cover 29 for protecting the two resistance heating elements 17. The cover 29 is attached to the drain pan 1 with fasteners such as bolts and nuts.
It is fixed at 6.

The operation of the cooling unit 4 of the automobile refrigeration system 1 will be briefly described with reference to FIGS. 1 to 3. When the automobile refrigeration system 1 starts the refrigeration operation, the relay switches 24 and 25 are closed and the relay switch 27
Is opened. Therefore, the air in the freezer compartment 3 is blown to the refrigerant evaporator 10 by the plurality of cooling fans 15. When the air is cooled below the dew point temperature by the refrigerant evaporator 10, the water in the air is condensed and the refrigerant evaporator 1
Water drops adhere to the surface of 0. Then, the water droplets freeze from the refrigerant evaporator 10 after being dropped on the drain pan 16 or remain on the surface of the refrigerant evaporator 10 and freeze.

When the temperature in the freezer compartment 3 drops to a predetermined temperature, the relay switch 25 is opened and the two resistance heating elements 17 limit the current supplied to the cooling fans 15 so that the refrigerant evaporator 10 can operate. Reduce the amount of air blown. At this time, the two resistance heating elements 17 generate heat when the two resistance heating elements 17 are energized.
The drain pan 16 to which the three resistance heating elements 17 are directly attached is heated. Therefore, the ice on the drain pan 16 is quickly thawed and drained to the outside of the freezer compartment 3 through the drain pipe 26. Therefore, the capacity of the drain pan 16 can be reduced, and the outer shape of the cooling unit 4 can be made compact.

When the preset conditions are met, the automobile refrigeration system 1 starts the defrosting operation. At this time, the relay switches 24 and 25 are opened and the relay switch 27
Is closed, and the three-way switching valve 6 is switched to the defrosting operation side. Then, the high-temperature and high-pressure refrigerant gas discharged from the discharge portion of the refrigerant compressor 5 directly flows into the refrigerant evaporator 10 via the bypass line 12, so that the ice frozen on the surface of the refrigerant evaporator 10 is thawed. , Water drops are dropped on the drain pan 16. At this time as well, since the drain pan 16 is heated by the two resistance heating elements 17, it is possible to prevent the growth and accumulation of ice due to the water droplets dropped from the refrigerant evaporator 10 being frozen again on the drain pan 16, and the drain can be quickly drained. It is drained to the outside of the freezer compartment 3 through the pipe 26.

Here, when the energizing currents of the plurality of cooling fans 15 are limited by the two resistance heating elements 17, that is, when the relay switch 24 is closed and the relay switches 25 and 27 are opened. There is a possibility that an overcurrent may flow through the two resistance heating elements 17 due to the plurality of cooling fans 15 being locked and the two resistance heating elements 17 may overheat. However, since the two resistance heating elements 17 of this embodiment are in direct contact with the drain pan 16 for receiving drain water and are provided in the cryogenic freezer compartment 3, the heat dissipation performance of the two resistance heating elements 17 is high. Can be prevented and the two resistance heating elements 17 can be prevented from overheating. Therefore, the resistance heating element 17 having excellent safety can be provided.

Also, the two resistance heating elements 17 of this embodiment are used.
Uses both the air flow rate variable register for limiting the current supplied to the cooling fan 15 and the planar heater for heating the drain pan 16, so that the number of parts can be reduced and the cost can be reduced.

In this embodiment, PT is used as the resistance heating element 17.
Although the planar heater having the C characteristic is used, a coil heater made of a metal resistor such as a nichrome wire may be used. As the resistance heating element, the kind, shape and number can be freely selected and changed as long as they satisfy the present invention. In this example,
Although the current flowing to the cooling fan 15 is limited by the resistance heating element 17, the current flowing to the capacitor fan may be limited by the resistance heating element. Further, the structure of the refrigeration cycle is not limited to this embodiment.

[0020]

According to the present invention, even if an overcurrent flows through the resistance heating element due to the blower being locked or the like and the resistance heating element generates heat, the heat of the resistance heating element quickly dissipates. Excessive temperature rise can be suppressed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a cooling unit of an automobile refrigeration system to which an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram showing a refrigeration cycle of an automobile refrigeration system to which an embodiment of the present invention is applied.

FIG. 3 is a main electric circuit diagram of an automobile refrigeration system to which an embodiment of the present invention is applied.

[Explanation of symbols]

 1 Refrigerating Device for Automobile 2 Refrigeration Cycle 4 Cooling Unit 7 Refrigerant Condenser 10 Refrigerant Evaporator 13 Condenser Fan 15 Cooling Fan (Blower) 16 Drain Pan 17 Resistance Heating Element

Claims (1)

[Claims] 1. A refrigeration cycle having (a) a refrigerant evaporator for evaporating a refrigerant and a refrigerant condenser for condensing the refrigerant, and (b) generating an air flow passing through the refrigerant evaporator or the refrigerant condenser. A blower; (c) a drain pan disposed below the refrigerant evaporator to receive drain water dropped from the refrigerant evaporator; A vehicle refrigeration system including a heating element.