JPH0517582Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a refrigeration system for a refrigerated vehicle, and particularly relates to a system that performs automatic defrosting operation when using a commercial power source. .

(Prior Art) Fig. 3 shows a refrigeration cycle of a general refrigeration system for a refrigerating vehicle equipped with a commercial power supply, showing a compressor 31 driven by the vehicle engine and a compressor 32 driven by a commercial power supply motor. A compressor selected from these compressors is driven by the power source used, and the high temperature and high pressure gas refrigerant discharged from the compressor is guided to the condenser 33 and liquefied there. Further, the refrigerant passes through a liquid tank 34 and a dryer 35, is depressurized by an expansion valve 36, and is then vaporized in an evaporator 37. after that,
The refrigerant enters the accumulator 38 and is sucked into the compressor 31 or 32 from there.

A vehicle power source or a commercial power source is connected to a cooling operation circuit equipped with such a refrigeration cycle through an operation switch 41 as shown in FIG. A defrosting mode changeover switch 42 and a defrosting control circuit 43 are connected to the defrosting mode changeover switch 42 . If the defrost mode selector switch 42 is set to the contact a position by manually switching contacts a, b, and c, the defrost control circuit is forced to start defrosting operation by manual operation. Manual defrost mode that sends a signal for defrosting, defrost stop mode that does not send a defrost operation start signal to the defrost control circuit when set to contact b position,
When set to contact c, each mode of the automatic defrosting mode is activated, which sends a signal to automatically start the defrosting operation based on a preset cycle or frost condition detection in the defrosting control circuit. It was configured to be

That is, when the operation switch 41 is turned on and the defrosting mode changeover switch 42 is connected to contact a while the cooling operation is being performed, the defrosting control circuit 43 opens the defrosting solenoid valve 39 shown in FIG. The refrigerant discharged from the compressor 31 or 32 is directly led to the evaporator 37, where defrosting is performed. Furthermore, when the defrosting mode changeover switch 42 is switched to contact c, the defrosting control circuit 43 automatically and intermittently operates the defrosting solenoid valve 3 using a timer or the like.
9 is opened and automatic defrosting operation is performed.

In addition, the defrosting mode changeover switch 42 operates manual defrosting with contact a, and after a signal is sent to the defrosting control circuit, the contact is automatically switched from contact a to contact b, and defrosting is stopped. Configured to remain in mode. In addition, when defrosting operation starts and defrosting is completed by automatic defrosting and manual defrosting,
Defrosting operation is automatically stopped and controlled to return to normal cooling operation mode.

(Problems to be Solved by the Invention) As described above, in the past, the defrosting mode selection switch was used to select the defrosting mode both when operating on vehicle power source and when operating on commercial power source. However, this has caused the following problems.

In other words, during operation, the defrost mode selector switch is set to control the timing of the defrost operation, depending on the outside air environment and the contents of the items to be cooled, so that the driver does not perform the defrost operation carelessly. There are cases where the defrost stop mode is set and defrosting is performed in the manual defrost mode when necessary.

In such cases, when the driver got out of the car and started driving the vehicle using the city power supply, he sometimes forgot to change the defrost mode switch to the automatic defrost mode while leaving the defrost mode switch in the defrost stop mode. In particular, when operating on a commercial power source, there is often no one present, so if continuous operation on the commercial power source is performed in the defrost stop mode, there is a risk of frost formation resulting in poor cooling or failure.

Thus, an object of the present invention is to provide a refrigeration system for a refrigerated vehicle that can solve the problems of the prior art described above and prevent frost formation during operation using a commercial power source.

[Structure of the invention] (Means for solving the problem) In order to achieve the above-mentioned purpose, the refrigeration system for a refrigerated vehicle of the invention is operated by electric power supplied from the vehicle power source or the city power source, and is automatically shut off. In a refrigerator vehicle refrigeration system equipped with a defrost selector switch for selecting either the manual defrost mode or automatic defrost mode with frost stop, the defrost mode selector switch is not activated during operation using vehicle power. The defrosting mode control means is provided to cause the defrosting device to operate based on the operating mode selected by the operator, and to perform automatic defrosting operation at all times regardless of the defrosting mode changeover switch during operation using the city power source. .

(Function) Although the system is often unmanned when operating on a commercial power source, if automatic defrosting operation is performed at all times when the commercial power source is operating as in the present invention, frost formation can be prevented and cooling failures and malfunctions can be avoided. I can do it.

Note that when the vehicle is powered on, the user can freely select each operation mode, and efficient cooling operation is performed.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an electrical system of a refrigeration system for a refrigerated vehicle according to an embodiment of the present invention. Similar to the refrigeration cycle shown in FIG. 3, this embodiment is equipped with a cooling operation circuit in which one refrigeration cycle is formed by a vehicle engine-driven compressor and a commercial power supply motor-driven compressor. A vehicle power source or a city power source is connected via the operation switch 1. In addition, this operation switch 1
Defrost mode switching relay 2 is installed between the and cooling operation circuit.
The movable contact f of the defrosting mode switching relay 2 is connected to the fixed contact d of the defrosting mode switching switch 3, and the movable contact g is connected to the automatic defrosting terminal h of the defrosting control circuit 4. each connected. Furthermore, the movable contacts a and c of the defrosting mode changeover switch 3 are connected to the manual defrosting terminal i and the automatic defrosting terminal h of the defrosting control circuit 4, respectively, and the movable contact b is not connected to anything and is in a free state. It's summery.

Note that the defrosting mode switching relay 2 is normally connected to the movable contact f side, and its relay coil is connected to a commercial power supply (not shown), and the relay coil is energized only when the commercial power supply is used. The defrosting mode switching relay 2 is configured to be connected to the movable contact g side.

In addition, the defrosting mode changeover switch 3 operates manual defrosting with contact a, and after a signal is sent to the defrosting control circuit, the contact automatically switches from contact a to contact b, and the defrost stop mode is activated. It is configured to be held in

Next, the operation of this embodiment will be described.

First, when the vehicle power supply is used, power from the vehicle power supply is supplied to the cooling operation circuit by turning on the operation switch 1, and cooling operation is performed. At this time, the defrosting mode switching relay 2 is connected to the movable contact f side. Therefore, when the user switches the defrosting mode changeover switch 3, power is selectively supplied to the terminal h or i of the defrosting control circuit 4, thereby operating in each mode.

In other words, the defrosting mode selector switch 3 is set to contact a.
When connected to the manual defrost terminal i of the defrost control circuit 4
The defrosting control circuit 4 opens the defrosting solenoid valve in the refrigeration cycle to perform defrosting. Furthermore, when the defrost mode selector switch 3 is switched to contact c, power is supplied to the automatic defrost terminal h of the defrost control circuit 4, and the defrost control circuit 4 automatically and intermittently uses a timer or the like. The defrosting solenoid valve is opened to perform automatic defrosting operation.
In addition, when operating in manual defrosting mode, by switching the normal defrosting mode selector switch 3 to contact b and connecting to contact a side when necessary, manual defrosting operation can be performed by stopping the automatic defrosting operation. Defrost mode available. Therefore, if contact b is present, the defrosting control circuit 4
Power is not supplied to the unit, defrosting operation is not performed, and cooling control operation continues. In addition, when the contact is switched to the a side to start manual defrosting, the contact is automatically switched back to the b side after the signal is supplied to the manual defrost terminal i of the defrost control circuit 4. It can be done.

Next, when the commercial power supply is used, the relay coil of the defrosting mode switching relay 2 is excited and the relay 2 is connected to the contact g side. Therefore, electric power from the city power supply is supplied to the automatic defrosting terminal h of the defrosting control circuit 4 via the operation switch 1 and the relay 2, so that the defrosting solenoid valve is automatically and intermittently opened. Automatic defrosting operation is performed. That is, the automatic defrosting operation mode is always set regardless of the setting of the defrosting mode changeover switch 3.

Note that the defrosting mode switching relay 2 can be driven by a method in which the defrosting mode switching relay 2 is driven when the vehicle power source is used, contrary to the above embodiment.

Also, a second defrost mode switching relay can be used instead of the defrosting mode switching relay 2.
As shown in the figure, a combination of a defrost return thermometer (thermal relay) 5 and a backflow prevention diode 6 is used to supply power from a commercial power supply to the automatic defrost terminal h of the defrost control circuit 4. You can also do that.

[Effects of the invention] As explained above, according to the present invention, the following excellent effects are exhibited.

(1) When using city power, automatic defrosting is always performed regardless of the defrost mode selector switch, so there is no risk of frost formation even when unattended, and cooling failures and breakdowns can be prevented. .

(2) In addition, when operating on a commercial power source, there is no need to switch the defrosting mode selector switch, simplifying the operation.

(3) When the vehicle is powered by a manned vehicle, each driving mode can be freely selected, making it possible to perform efficient cooling.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an electrical system of a refrigeration system for a refrigerated vehicle according to one embodiment of the present invention, Fig. 2 is a circuit diagram showing another embodiment, and Fig. 3 is a general refrigeration system for a refrigerated vehicle. FIG. 4 is a circuit diagram showing a conventional example. In the figure, 1 is an operation switch, 2 is a defrosting mode switching relay, 3 is a defrosting mode switching switch, and 4 is a defrosting control circuit.

Claims (1)

[Scope of utility model registration request] A refrigeration unit that is operated by electric power supplied from a vehicle power source or a city power source, and is equipped with a defrost switching device for selecting either the manual defrosting mode with automatic defrosting stop or the automatic defrosting mode. In a vehicle refrigeration system, the vehicle is operated based on the operation mode selected by the defrosting switching device when the vehicle is powered by the power supply, and is always operated based on the automatic defrosting operation mode when the vehicle is operated using the city power supply. A refrigeration system for a refrigerated vehicle, characterized in that the refrigeration system is equipped with a defrosting control means.