JPS6222805B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vehicle cooling system, and relates to one in which a compressor is stopped after a so-called frost phenomenon begins.

(Prior art) Conventionally, in a vehicle cooling system, a cooling medium such as fluorocarbon gas is evaporated in an evaporator, and a blower is used to blow air into the evaporator. The air is blown out into the passenger compartment. This cooling system controls the air temperature at the outlet of the evaporator so that the inside of the vehicle reaches the desired temperature. In some cases, the evaporator outlet temperature may be below 0°C. On the other hand, the evaporator also performs a dehumidifying function, which causes the problem that this dehumidified moisture freezes in the air passages of the evaporator, causing a frost phenomenon, making it difficult for air to flow and cooling to be effective.

Therefore, in order to solve the above problems, as described in Japanese Utility Model Application Publication No. 54-130741,
Some were equipped with a control means that temporarily stops the refrigeration cycle when the indoor temperature falls below a predetermined temperature.

(Purpose of the Invention) By the way, the present inventor discovered that the above-mentioned conventional device stops the refrigeration cycle depending on the indoor temperature, so the cooling capacity of the device is not maximized. The present invention was created in order to make maximum use of this ability.
That is, an object of the present invention is to provide a cooling system for a vehicle that can maximize the cooling capacity of the cooling system and prevent the frost phenomenon.

(Structure of the Invention) The present invention focuses on the fact that the blower current decreases when a frost phenomenon occurs in the evaporator, and provides a memory circuit that stores in advance different current values for each fan air volume level of the blower. A detection circuit that detects the actual blower current value, a comparison circuit that compares the current value of the storage circuit and the current value of the detection circuit at the fan operating air volume level at that time; A compressor control device is provided which stops the compressor when the current value of the detection circuit is smaller than the current value of the storage circuit, and restarts the compressor when the current value of the detection circuit becomes larger than the current value of the storage circuit. As a result, the compressor is stopped after the frost phenomenon actually starts, and restarted after the frost phenomenon subsides.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a vehicle cooling device according to an embodiment of the present invention, and in FIG. 1 showing the refrigeration system, 1 is an air passage for introducing inside air or outside air into the passenger compartment; A blower 2 is disposed in the air passage 1, and is used to blow the inside air or outside air by rotating blades 2b by a blower motor 2a. Further, an evaporator 3 is disposed downstream of the blower 2 in the air passage 1. The evaporator 3 evaporates the fluorocarbon gas, which is a cooling medium, inside the evaporator 3, and absorbs the heat of evaporation from the air passing through it to cool the air.

And the freon gas outlet 3 of the evaporator 3
A compressor 5, a condenser 6, a liquid tank 7, and an expansion valve 8 are provided in this order in a fluorocarbon gas passage 4 that communicates the fluorocarbon gas inlet 3b with the fluorocarbon gas inlet 3b. The compressor 5 can be connected to and connected to the engine by a magnetic clutch 5a, and is driven by the engine to compress fluorocarbon gas and send it to the fluorocarbon gas passage 4 under high pressure. Further, a large number of cooling fins 6a are attached to the condenser 6, and a cooling fan 6b is provided behind the condenser 6, and this condenser 6 cools and liquefies the fluorocarbon gas that has been compressed by the compressor 5 and becomes high temperature. The liquid tank 7 is used to adjust the flow of the fluorocarbon gas liquefied by the condenser 6. The expansion valve 8 is used to adiabatically expand the liquid fluorocarbon gas and supply it to the evaporator 3 in this state.

Further, FIGS. 2 and 3 show electrical circuit diagrams of the device of this embodiment, and in the figures, 10 is a battery, and 11 is a battery.
12 is an ammeter, and 12 is a blower switch, which has an off terminal 13 and 1st to 4th use stage terminals 14a to 14.
14d, 1st to 4th use stage detection terminals 15a to 1
5d, a common terminal 16a, and a contact 16, and resistors 17a to 17c are connected between each of the use stage terminals 14a to 14d, and the common terminal 16a is grounded.

Further, 18 is an air conditioner switch, 19 is a compressor control device, 21 is a relay whose relay contact 21b is turned off when the relay coil 21a is energized, and 5
a is a magnetic clutch of the compressor 5 shown in FIG.

The compressor control device 19 opens and closes the current supply circuit to the relay coil 21a of the air conditioner relay 21 in accordance with the current value of the blower motor 2a.
The load current value of the blower motor 2a at each operating stage of the blower switch 12 is stored in advance in the memory circuit 20. The storage circuit 20 is connected to each use stage detection terminal 15a to 15a of the blower switch 12 from outside the control device 19.
A signal 15d is inputted, and a signal corresponding to the stored current value at the current stage of use is read out by inputting this signal. The control device 19 is also provided with a detection circuit 22 that receives the output of the ammeter 11 and generates a signal corresponding to the blower current value. Furthermore, the control device 19 includes a comparison circuit 23 that compares the blower current value with the stored current value, and a control that receives a signal from the comparison circuit 23 and closes the energizing circuit to the relay coil 21a when the blower current value is small. A circuit 24 is provided.

By the way, a vehicle cooling system is generally provided with a control device that connects and disconnects the magnetic clutch 5a of the compressor 5 depending on the temperature inside the vehicle and other conditions, and this embodiment is of course provided with this control device. , illustration is omitted for simplicity.

Next, the operation will be explained.

If you want to cool the interior of the vehicle while the engine is running, turn the contact 16 of the blower switch 12 to any one of the first to fourth use level terminals 14a to 14d, for example, the first use level terminal 14a, and turn the air conditioner switch 18 on. Turn on. Then the blower motor 2a
As the motor rotates, the actual motor current value at that point is measured from the ammeter 11 in the compressor control device 1.
9 is input to the detection circuit 22 of the compressor controller 19, and at the same time, the contact 16 comes into contact with the first use stage detection terminal 15a, the potential of this detection terminal 15a becomes the ground potential, and this is input to the storage circuit 20 of the compressor control device 19. A storage current value corresponding to the first use stage is read from the storage circuit 20. Then, the control device 19 compares the read memory current value and the motor current value in the comparison circuit 23, and compares the read memory current value with the motor current value.
Input the signal to. In this case, since the motor current value is larger, the control circuit 24
The energizing circuit to the relay coil 21a of No. 1 is opened, and the relay coil 21a is not energized, so the relay contact 21b remains closed, which turns on the magnetic clutch 5a and connects the compressor 5 to the engine. and start it.

Then, in the refrigeration system shown in FIG. 1, the fluorocarbon gas first circulates in the fluorocarbon gas passage 4, is evaporated in the evaporator 3, and the air passing through it is cooled, and the cooled air is blown into the vehicle interior. Become. Also, this blown air is dehumidified when passing through the evaporator 3, and the water generated by the dehumidification is removed from the air outlet 3 of the evaporator 3.
Water is drained from the drain pipe 3d through the vicinity of c.

If the required temperature inside the vehicle is set to a considerably low level, or depending on outside air conditions, the temperature near the air outlet 3c of the evaporator 3 may drop to 0.
℃ or lower, and in such a case, the dehumidified water gradually freezes and adheres to the surface of the air outlet 3c of the evaporator 3, creating air flow resistance. Then, as this resistance increases, the load current of the blower motor 2a gradually decreases.

In this case, returning to Figures 2 and 3,
When the blower current value input from the ammeter 11 to the compressor control device 19 becomes smaller than the above-mentioned memorized current value due to a decrease in the blower motor current, the control circuit 24 of the above-mentioned control device 19 causes the above-mentioned relay coil 21
The energizing circuit to a is closed, the relay coil 21a is energized and the relay contact 21b is opened, which turns off the magnetic clutch 5a and turns off the compressor 5.
As a result, the refrigeration cycle is stopped and the fluorocarbon gas no longer evaporates in the evaporator 3.

Next, by stopping this refrigeration cycle, the temperature near the air outlet 3c of the evaporator 3 rises, and the frozen ice gradually melts, and as the ice melts, the blower current value increases, which causes the above-mentioned When it becomes larger than the memorized current value,
The control circuit 24 of the compressor control device 19 opens the energizing circuit to the relay coil 21a, the magnetic clutch 5a is turned on, the compressor 5 is started again, and the air cooled by the evaporator 3 is blown into the passenger compartment. becomes.

In this way, in the device of this embodiment, the evaporator 3
The compressor 5 is disconnected from the engine when the air outlet 3c becomes narrow due to ice and the motor current becomes small, and then when the frozen ice melts and the blower current increases, the compressor 5 and the engine are connected. There is no need to stop the compressor earlier than in other systems, and the cooling capacity of this cooling system can be brought out to its limit.

(Effects of the Invention) As described above, according to the vehicle cooling device according to the present invention, there is provided a memory circuit that stores different current values at each operating air volume level of the blower, and a detection circuit that detects the actual blower current value. a comparator circuit that compares the current value of the memory circuit and the current value of the detection circuit for the air flow level used by the fan at that time; A compressor control device is provided that stops the compressor and restarts the compressor when the current returns to the memorized current value, so that the compressor is stopped after frost has actually started, and the compressor is restarted after the frost phenomenon subsides. This has the effect of drawing out the cooling capacity to its limit.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a vehicle cooling system according to an embodiment of the present invention, and FIGS. 2 and 3 are electrical circuit diagrams thereof. 2... Blower, 3... Evaporator, 5... Compressor, 19... Compressor control device, 2
0...Memory circuit.

Claims (1)

[Claims] 1. In a vehicle equipped with an air conditioner, an evaporator that evaporates a cooling medium, a blower that generates an air flow passing through the evaporator, and a current value that is different for each fan air volume level of the blower are stored. a memory circuit, a detection circuit that detects the actual blower current value, a comparison circuit that compares the current value of the memory circuit and the current value of the detection circuit at the fan operating air volume level at that time; , outputs a signal to stop the compressor when the current value of the detection circuit is smaller than the current value of the storage circuit, and restarts the compressor when the current value of the detection circuit becomes larger than the current value of the storage circuit. A vehicle cooling device characterized by comprising a compressor control device that outputs a signal.