JPS63192606A - Cooling/refrigerating device for vehicle - Google Patents

Abstract

PURPOSE:To enhance refrigerating characteristics by juxtaposing No.2 flow path having a refrigerating expansion valve and a refrigerating evaporator, shutting the No.1 flow path and opening No.2 flow path for refrigerating when a cooler evaporator is sensed to be frozen. CONSTITUTION:A compressor 3 is put in service by engaging an electromagnetic clutch 2, and at the same time, a signal is given to a control device 19 from a thermoswitch 18. Unless a cooler evaporator 9 is under the freezing temp., signal on a tire circuit 16 is fed to drive a cooling electromagnetic valve 7 so as to open in the same phase as a timer circuit 16 and in the opposite phase to a refrigerating electromagnetic valve 10, and the cooler evaporator 9 is operated with a fixed cycle. Now refrigerating run is introduced in the opposite phase to operation and stop of cooling. When the cooler evaporator 9 becomes below the freezing temp., signal feeding to the time circuit 16 is shut, and the electromagnetic valve 7 is closed while the one 10 left open solely, and now the cooling run is stopped to allow the whole cooling power to serve for refriger ation. This constitution enhances the refrigerating ability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air-conditioning/refrigeration system for a vehicle that improves refrigeration performance by effectively utilizing surplus cooling power when a cooling evaporator is frozen.

2. Description of the Related Art As a conventional vehicle cooling system, the structure shown in FIG. 3 has been proposed (see Japanese Patent Laid-Open No. 144856/1983). [In other words, a vapor compression type refrigeration cycle] Haku has a compressor 3 connected to an engine (not shown) via an electromagnetic clutch 2, and a condenser 4 that cools and liquefies high-temperature, high-pressure refrigerant fed from the compressor 3. There is. A first flow path 5 and a second flow path 6 are arranged in parallel on the downstream side of the condenser 4, and the first flow path 5 includes a cooling solenoid valve 7 and a cooling expansion valve 8. A cooling evaporator 9 is provided. Further, the #g2 flow path 6 is provided with a refrigeration solenoid valve lO2 refrigeration expansion valve ll and a refrigeration evaporator 12, and the refrigeration evaporator 12 is disposed inside the vehicle interior and surrounded by a heat insulating material. It is arranged in a cold storage 13. A thermistor 14 is attached to the cooling evaporator 9 to detect its surface temperature, and a detection signal from the thermistor 14 is input to a thermoswitch 15 that connects and disconnects the electromagnetic clutch. On the other hand, both the solenoid valves 7. IO
is connected to a drive device 17 that outputs a control signal in accordance with the output of the timer circuit 16. In such a structure, when the timer circuit 16 repeats the ON state for 15 seconds and the OFF state for 15 seconds, for example, as shown in Fig. g3, the drive device 1
7 is a cooling solenoid valve 7 according to the output of this timer circuit 16.
is driven to open in the same phase as the timer circuit 16, and the refrigeration solenoid valve lO is opened in the opposite phase. Therefore, the air conditioner is 15
The heating is carried out every second and the cooling is carried out for 15 seconds every second, so that the interior of the vehicle and the inside of the refrigerator 13 can be appropriately cooled. Also, when the surface of the cooling evaporator 9 is at freezing temperature, 190
When the temperature drops to 0.degree. C., the thermistor 14 detects this, the thermoswitch 15 is activated, and the electromagnetic clutch 2 is disconnected. Therefore, the compressor 3 is stopped and the cooling evaporator 9 is prevented from freezing. Note that when cooling the refrigerator 13 side, the electromagnetic clutch 2 is connected regardless of the state of the thermoswitch 15.

Problems to be Solved by the Invention However, in these conventional devices, during the time allotted for cooling, the amount of cooling heat is reduced relative to the cooling capacity, such as when driving at high speed or when the cooling fan is operating at low speed. When the load is small and the surface of the cooling evaporator 9 reaches a freezing temperature, the thermoswitch 15 is activated to disconnect the electromagnetic clutch 2 and stop the compressor 3 as described above. At this time, thermo switch 15
In order to prevent hunting, the compressor 3 has a hysteresis of about 4° C., so during cooling, the compressor 3 is maintained in an open/stopped state until the surface degree of the cooling evaporator 9 rises by 4° C. Therefore, while the cooling evaporator 9 is reliably prevented from freezing, the refrigeration cycle, which contributes to cooling both the air conditioner and the refrigerator, frequently stops during this period, and the second flow, which has a relatively short refrigerant flow time, On the road 6 side, it was not possible to rapidly cool the refrigerated items in the refrigerator 13.

Means for Solving the Problems The present invention has been made in view of the problems of the prior art. The first flow path has a cooling expansion valve and a cooling evaporator on the downstream side of the condenser, and a refrigeration expansion valve and a refrigeration evaporator! In addition to arranging two flow paths in parallel,
A valve body for selectively opening and closing the flow path is provided, and a detector is provided for detecting freezing of the cooling evaporator, and the valve body is driven to open and close at predetermined time intervals, and based on a freeze detection signal from the detector. A control device is provided for forcibly driving the valve body to close the first flow path and open the second flow path.

Operation In the above configuration, the control device drives the valve body to open and close at predetermined time intervals, thereby selectively opening and closing the first flow path and the second flow path, thereby supplying refrigerant to the cooling evaporator side; Refrigeration and refrigeration in which refrigerant is supplied to the refrigeration evaporator side are performed alternately. When the cooling evaporator freezes, when the cooling heat load is small compared to the cooling capacity due to cooling inside the vehicle, the detector detects this, and the control device operates based on the signal from the detector. The valve body is forcibly driven to a position where the first flow path is closed and the second flow path is opened.

Therefore, surplus refrigerant during cooling is fed to the refrigeration evaporator provided in the second flow path and effectively utilized for refrigeration.

Example An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a vapor compression type refrigeration cycle 1 is provided with a compressor 3 connected to a cylinder (not shown) via an electromagnetic clutch 2. A condenser 4 that cools and liquefies a high-temperature, high-pressure refrigerant is provided downstream of the refrigerant 3 . Furthermore, the capacitor 4
A first flow path 5 and a second flow path 6 are arranged in parallel on the downstream side of the . A cooling evaporator 9 is provided.

Further, the second flow path 6 is provided with a refrigeration solenoid valve 10 serving as a valve body, a refrigeration expansion valve 11 , and a refrigeration evaporator 12. It is arranged in an enclosed refrigerator 13. The cooling evaporator 9 has a detection mechanism that includes a thermistor 14 that detects the surface temperature of the cooling evaporator 9, and a thermoswitch 18 that closes the circuit when the surface temperature of the cooling evaporator 9 detected by the thermistor 14 reaches 0°C. is provided, and the 0N (k number, that is, the freeze detection signal) output from the thermoswitch 18 is configured to be input to the control device 19.The control device 19 is configured to:
For example, as shown in Fig. 4, the addition ON state, 15 seconds OF
A circuit connected to the timer circuit 16 that repeats the F state, and which opens the cooling solenoid valve 7 in the same phase as the timer circuit 16 and opens the refrigeration solenoid valve lO in the opposite phase, and the freeze detection signal. The valve bodies 7 and 10 are forcibly driven based on the flow path 5.
It also has a circuit for closing the second flow path 6.

Next, the operation of this embodiment according to the above configuration will be explained according to the flowchart shown in FIG.

That is, when the cooling/refrigeration switch (not shown) is turned on, the electric clutch 2 is connected and the compressor 3 is operated. Meanwhile, the control device 19 is activated at the same time and reads the signal from the thermo switch 18 (step 2). Next, based on this signal, it is determined whether or not the cooling evaporator 9 has reached a temperature at which it can freeze. The solenoid valve 7 is selectively driven to open in the same phase as the timer circuit 16, and the refrigeration solenoid valve IO is opened in the opposite phase. Therefore, the air conditioner, in which refrigerant is supplied to the cooling evaporator 9, is turned off every 15 seconds, and the refrigeration, in which refrigerant is fed to the refrigeration evaporator 12, is turned off every 15 seconds.
This is carried out for seconds (step ①), and the interior of the vehicle and the inside of the refrigerator 13 are appropriately cooled. And when driving at high speed and for cooling air/
When the cooling heat load is small relative to the cooling capacity, such as during low-speed operation, when the surface of the cooling evaporator 9 reaches a freezing temperature, the thermistor 14 senses this and sends a signal to the thermoswitch 18. Output. Then, the thermoswitch 18 outputs an ON signal to the control device 19, and the determination in step (2) becomes YES. Then, based on the ON signal, the control device 19 cuts off the signal input to the timer circuit 16 until the surface temperature of the cooling evaporator 9 rises from the freezing temperature by, for example, +4° C., and turns off the cooling solenoid valve 7.
Forcibly drive the refrigeration solenoid valve lO to close and open. This is K
Therefore, the flow path 5 is closed and the second flow path 6 is opened (step ■), and the surplus refrigerant during cooling is pumped through the air conditioner 4 as the compressor continues to operate 30 times. Refrigeration evaporator 1 of second flow path 6 via
2. Therefore, the refrigeration time can be increased by effectively utilizing surplus cooling power without affecting the cooling capacity during cooling, and the cooling rate and cooling maintenance performance of refrigerated items can be improved.

In the above embodiment, the surface temperature of the cooling evaporator 9 was detected by the thermistor 14, but it is also possible to detect freezing from the degree of conductivity on the surface of the cooling evaporator 9.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a refrigeration cycle in which a first passage having a cooling expansion valve and a cooling evaporator is arranged in parallel with a second passage having a cooling expansion valve and a refrigeration evaporator. 1. The second flow path is opened and closed at predetermined time intervals, and when the cooling evaporator reaches a freezing temperature, one flow path is forcibly closed and the second flow path is opened. Therefore, without affecting the cooling capacity during cooling, it is possible to effectively utilize the excess cooling power within the capacity of the refrigeration cycle to increase the refrigeration time, thereby improving the cooling rate and cooling maintenance performance of refrigerated items. It becomes possible to aim for improvement. Moreover, since the situation in which the evaporator temperature drops and the thermoswitch operates generally occurs under all conditions except during the cool-down period when the air conditioner is initially started, the above effect is actually always present. It is something that can be demonstrated.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing an embodiment of the present invention, Fig. 2 is a flowchart showing the operation of the same embodiment, Fig. 3 is a conceptual diagram showing a conventional vehicle cooling/refrigeration system, and Fig. 4 is a conceptual diagram showing an embodiment of the present invention. Channel and second
FIG. 3 is an explanatory diagram showing an example of flow path switching control characteristics. ]... Refrigeration cycle, 3... Compressor, 4...
- Capacitor, 5th... flow path, 6... second flow path,
7... Solenoid valve for cooling (valve body), 8... Expansion valve for cooling, 9... Evaporator for cooling, lO... Solenoid valve for refrigeration (valve body), 11... Expansion for refrigeration Valve, 12... Refrigeration evaporator, 19... Control device, Nod... Detector. Figure 1

Claims (1)

[Claims] (1) A condenser is disposed downstream of a compressor of a refrigeration cycle driven by an engine, and a first flow path having a cooling expansion valve and a cooling evaporator downstream of the condenser; A second flow path having an evaporator is installed in parallel, and the first and second flow paths are arranged in parallel.
A valve body for selectively opening and closing the flow path is provided, and a detector is provided for detecting freezing of the cooling evaporator, and the valve body is driven to open and close at predetermined time intervals, and based on a freeze detection signal from the detector. 1. A vehicle cooling and refrigerating device, comprising: a control device that forcibly drives a valve body to close the first flow path and close the second flow path.