JPH0560427A - Freezing device for transportation - Google Patents

Abstract

PURPOSE:To rapidly decrease temperature in a chamber to a given value by a method wherein the number of revolutions of an engine is increased when temperature in a refrigerator is not reduced to a predetermined value after a laps of a given time starting from the starting of running of an engine. CONSTITUTION:When temperature T in a chamber is not reduced to a given temperature Ta after a laps of a given time starting from the starting of low speed operation of an engine 1, the engine 1 is shifted to high speed operation by means of a control device 21, and along with the shift, cooling capacity of a freezing device is increased and the interior of a chamber is rapidly cooled. When temperature in the chamber is reduced to a set temperature Ts, the engine 1 is brought into a stop to stop cooling operation. In this way, cooling capacity is increased, the interior of the chamber is rapidly cooled to the set temperature TS, the operation time of the engine 1 can be shortened, and an amount of consuming fuel can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system such as a transportation refrigeration unit driven by an engine.

[0002]

2. Description of the Related Art An example of a conventional refrigeration system is shown in FIG. In FIG. 4, reference numeral 1 denotes an engine, the rotational speed of which is increased or decreased stepwise. Reference numeral 3 is a compressor driven by the engine. Reference numeral 5 is a three-way valve, which is driven by a solenoid 6 to switch between cooling operation and heating operation. Reference numeral 7 is a condenser, 8 is a fan for blowing outside air to the condenser 7, and is a motor 9
Driven by. Reference numeral 10 is an expansion valve, 11 is an evaporator arranged in a freezer, 13 is a fan for blowing the air in the refrigerator to the evaporator 11, and is driven by a motor 14.

Reference numeral 15 is a thermosensor for detecting the temperature in the freezer, 16 is a control device, 17 is a generator driven by the engine 1, 18 is a battery charged by the generator 17, and 19 is a charge amount of the battery. It is a charging sensor.

During the cooling operation, the refrigerant is the compressor 3, the three-way valve 5, the condenser 7, and the expansion valve 1 as shown by the solid arrow.
0, the evaporator 11 and the compressor 3 in this order.

On the other hand, during the heating operation, the refrigerant returns to the compressor 3 through the compressor 3, the three-way valve 5 and the evaporator 11 in this order as shown by the broken line arrow.

The output of the thermosensor 15 is input to the control device 16, and the engine 1, the solenoid 6, the motor 9, and the motor 14 are controlled by a command from the control device 16. The control device 16 has a built-in thermostat TH1, thermostat TH2, thermostat TH3, and thermostat TH4. As shown in FIG. When it reaches the bottom of
It becomes F. Further, the thermostat TH2 is turned off when the inside temperature T reaches the set temperature Ts, and is turned on when the inside temperature T rises and reaches the upper limit temperature T2.

On the other hand, the thermostat TH4 has an internal temperature T
When the temperature reaches the lower limit temperature T4, it becomes ON, and when it reaches the lower limit temperature T3, it becomes OFF. Further, the thermostat TH3 is turned off when the internal temperature T reaches the set temperature Ts, and is turned on when the internal temperature T reaches the lower limit temperature T3.

When the load is the cooling load, the cooling operation shown by the solid line in FIG. 6 is performed, and when the load is the heating load, the heating operation shown by the broken line in FIG. 6 is performed.

During the cooling operation, when the internal temperature T is higher than the point I, that is, higher than the upper limit temperature T1 of the thermostat TH1, the command of the thermostat TH1 causes the engine 1 to operate at high speed with a high rotational speed. The generator 17 is driven by 1 to charge the battery 18, and the motor 9 and the motor 14 are driven by the generator 17, so that the refrigerating apparatus is cooled with a high cooling capacity.

When the inside temperature T gradually decreases and reaches the upper limit temperature T2 due to the cooling operation of the refrigerating apparatus, that is, at the point B, the engine 1 is operated at a low speed with a low rotation speed, and accordingly the refrigerating apparatus. The cooling capacity of is reduced and the interior is gradually cooled. When the internal temperature T decreases and reaches the set temperature Ts, that is, at the point C, the engine 1
Is stopped and the cooling operation is stopped. Then, after the cooling operation is stopped, when the temperature in the refrigerator rises due to the intrusion of heat from the outside or the like to reach the upper limit temperature T2 of the thermostat TH2, that is, at the two points, the engine 1 is restarted by the instruction of the thermostat TH2, Low speed operation is started.

On the other hand, during the heating operation, when the internal temperature T is lower than the lower and lower limit temperature T4 of the thermostat TH4, the engine 1
Is operated at a high speed to perform a heating operation under a high heating capacity. Then, when the internal temperature T rises to reach the lower limit temperature T3, the engine 1 is operated at a low speed to perform a heating operation under a low heating capacity. When the internal temperature T further rises and reaches the set temperature Ts, the engine 1 is stopped and the heating operation is stopped. Others are the same as in the cooling operation.

[0012]

The above-mentioned conventional transportation refrigeration system has the following problems to be solved.

That is, in the above-mentioned conventional transportation refrigeration system, the rotational speed of the engine 1 is increased / decreased in response to a thermostat command to perform high-speed operation and low-speed operation, thereby increasing / decreasing the cooling capacity or the heating capacity.

However, for example, in the cooling operation of the refrigeration system, when the cooling load is lower than the cooling capacity in the high speed operation but higher than the cooling capacity in the low speed operation, the high speed operation based on the commands of the thermostat TH1 and the thermostat TH2 is performed. Or even if the cooling operation by low speed operation is continued for a long time, the inside of the refrigerator will not be cooled to the set temperature,
In addition to increasing the fuel consumption of the engine, there is a possibility that proper temperature control cannot be performed and the quality of the cooled object may deteriorate.

Further, there is a problem that the same problem as in the above case is brought about even under the heating operation of the refrigerating apparatus.

In order to solve the above problems, the present invention allows the control means to increase the engine rotation speed and reach the predetermined temperature rapidly when the inside of the refrigerator has not reached the predetermined temperature after a predetermined time after the start of operation. It is an object of the present invention to provide a transport refrigeration system that can be used.

[0017]

As a means for solving the above problems, the present invention controls the temperature in a freezer by being driven by an engine together with a battery charging generator, and by increasing or decreasing the number of revolutions of the engine. In the transportation refrigeration apparatus configured as described above, when the temperature in the freezer does not reach a predetermined temperature according to the number of revolutions of the engine after a predetermined time has elapsed from when the engine was started at an arbitrary number of revolutions, or When the internal temperature of the freezer does not reach a predetermined temperature according to the engine speed after a predetermined time has elapsed from the start of operation at an arbitrary engine speed, and the charging of the battery is completed, the engine An object of the present invention is to provide a transport refrigeration system characterized by comprising control means for increasing the number of rotations of the.

[0018]

Since the present invention has the above-mentioned structure, when the temperature in the freezer does not reach the predetermined temperature according to the engine speed within a predetermined time from when the engine is operated at an arbitrary speed. The engine speed is increased by the control means. As a result, the cooling capacity or heating capacity of the refrigerating apparatus is increased, the inside of the freezer is rapidly cooled or heated, the temperature inside the freezer is lowered or raised, and the operating time of the engine is shortened.

Further, within a predetermined time from when the engine is operated at an arbitrary rotation speed, the temperature inside the freezer does not reach a predetermined temperature according to the rotation speed of the engine, and charging of the battery is completed. While the engine is running, the control means increases the engine speed. As a result, the cooling capacity or heating capacity of the refrigerating apparatus is increased, the inside of the freezer is rapidly cooled or heated, the temperature inside the freezer is lowered or raised, and the operating time of the engine is shortened. Furthermore, since the battery has a sufficient charge, it is possible to avoid a situation where the battery is insufficiently charged due to the shortened engine operating time.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a system diagram of a transportation refrigerating apparatus according to this embodiment,
FIG. 2 is a control flow chart thereof.

In FIG. 1, the control device 21 incorporates a thermostat TH1, a thermostat TH2, a thermostat TH3, and a thermostat TH4, and inputs a signal from the thermosensor 15 as in the conventional case shown in FIG. , High-speed operation of engine 1 with high rotation speed,
In addition to controlling the low speed operation with a low rotation speed or operation stop, and controlling the solenoid 6, the motor 9, and the motor 14, FIG.
The engine 1 is controlled to switch from low speed operation to high speed operation in accordance with the control flow shown in FIG. Other configurations are the same as those of the conventional one shown in FIG. 4, and corresponding members are designated by the same reference numerals and the description thereof is omitted.

Next, the operation of the above embodiment will be described.
During the cooling operation of the refrigeration system, the engine 1 is operated at a high speed to lower the internal temperature T, and when the upper limit temperature T2 is reached, the engine 1 is operated at a low speed according to a command from the thermostat TH2 of the control device 21. After a predetermined time has passed from the start of low-speed operation of the engine 1, the internal temperature T decreases and the set temperature T
When s is reached, the engine 1 is stopped by the instruction of the thermostat TH2 and the cooling operation is stopped.

After the cooling operation is stopped, when the temperature in the refrigerator rises to reach the upper limit temperature T2 of the thermostat TH2 due to the intrusion of heat from the outside or the like, the engine 1 is restarted and the low speed operation is started. It

On the other hand, when the internal temperature T does not reach the set temperature Ts after a lapse of a predetermined time from the start of the low speed operation of the engine 1, the engine 1 is switched to the high speed operation, and the cooling capacity of the refrigerating device is accordingly accompanied. Is increased and the inside of the refrigerator is cooled rapidly. Next, when the inside of the refrigerator is lowered to the set temperature Ts, the engine 1 is stopped and the cooling operation is stopped.

Thus, when the engine 1 is operated at a low speed and the cooling load is large or nearly equal to the cooling capacity at the low speed operation, in the conventional example, the internal temperature T is kept even if the cooling operation is continued for a long time. Although the temperature is not lowered to the set temperature Ts, in the present embodiment, the cooling capacity is increased by operating the engine 1 at a high speed, whereby the inside of the refrigerator can be rapidly cooled to the set temperature Ts, and the engine 1 Driving time can be shortened.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a control flowchart showing the second embodiment. In the present embodiment, under low speed operation of the engine 1, the internal temperature reaches the set temperature Ts after a predetermined time from the start of the low speed operation, and the charging of the battery 18 detected by the charge sensor 19 is completed. When it is, the control device 21 stops the engine 1 and the cooling operation is stopped. That is, in the case of the present embodiment, the control device 21 is configured so that the charge completion signal of the battery 18 is added to the stop condition of the engine 1.

On the other hand, in the case where the internal temperature of the refrigerator has not reached the set temperature Ts after a predetermined time has elapsed since the engine 1 started to operate at a low speed, when the battery 18 is completely charged, the engine 21 is controlled by the control device 21. The engine 1 is switched to the high speed operation, and the low speed operation is continued when the charging of the battery 18 is not completed, and the engine 1 is switched to the high speed operation when the charging of the battery 18 is completed. Other configurations and operations are similar to those of the first embodiment shown in FIGS.

Thus, also in the second embodiment, the cooling capacity is increased by operating the engine 1 at high speed,
As a result, the inside of the refrigerator can be rapidly cooled to the set temperature Ts, and the operating time of the engine 1 can be shortened.

Furthermore, since the battery 18 is sufficiently charged, it is possible to avoid a situation where the battery 18 is insufficiently charged due to the shortened operating time of the engine 1.

Although the first and second embodiments have been described in the case of the cooling operation of the refrigeration system, the same applies to the case of the heating operation.

Further, in both the first and second embodiments, the engine 1 is operated at two different rotation speeds (low speed operation, high speed operation).
It is needless to say that the present invention can be applied even when operating at three or more different rotation speeds.

As described above, according to the first embodiment, the control device 21 controls the engine 21 when the internal temperature of the refrigerator, which has been determined in correspondence with the engine speed, has not been reached even after the lapse of a predetermined time after the start of the engine operation. Since the rotation is increased, it is possible to quickly reach the predetermined internal chamber temperature. Therefore, after the engine temperature is rapidly reached to the predetermined internal temperature, the engine is stopped, so that there is an advantage that the problem that the operation is continued and the fuel consumption is increased can be solved. Further, there is an advantage that the quality of the object to be cooled does not deteriorate because the state where the predetermined internal temperature is not reached does not continue for a long time.

Further, according to the second embodiment, when the internal temperature of the cold storage corresponding to the engine speed has not been reached even after a lapse of a predetermined time after the start of operation of the engine, the charging of the battery is completed. If so, the engine speed is increased by the control device 21. Therefore, in addition to the advantages of the first embodiment, there is an advantage of avoiding the problem that the engine is stopped while the battery is insufficiently charged.

[0034]

Since the present invention is constructed as described above, it has the following effects.

That is, according to the present invention, when the temperature in the freezer does not reach the temperature predetermined according to the engine speed after a predetermined time has passed since the engine was operated at an arbitrary engine speed, the engine speed is changed. Since the number is increased and the cooling capacity or the heating capacity of the refrigerating apparatus is increased, the inside of the freezer can be maintained at the set temperature, the operating time of the engine can be shortened, and the fuel consumption thereof can be reduced. ..

Further, after a predetermined time has elapsed since the engine was operated at an arbitrary rotation speed, the temperature inside the freezer has not reached a predetermined temperature according to the rotation speed of the engine, and the charging of the battery is completed. At this time, the engine speed is increased, so that the interior of the freezer can be maintained at the set temperature and the fuel consumption of the engine can be reduced as described above. Further, it is possible to avoid the situation where the battery is insufficiently charged even by shortening the operating time due to the increase in the engine speed.

[Brief description of drawings]

FIG. 1 is a system diagram of a transportation refrigeration apparatus according to a first embodiment of the present invention,

FIG. 2 is a control flowchart of the first embodiment,

FIG. 3 is a control flowchart of the second embodiment of the present invention,

FIG. 4 is a system diagram showing a conventional refrigeration system,

FIG. 5 is a switching diagram of a conventional thermostat,

FIG. 6 is an operation switching diagram of a conventional refrigeration system.

[Explanation of symbols]

 1 Engine 15 Thermosensor 17 Generator 18 Battery 19 Charge Sensor 21 Control Device

Claims (1)

[Claims] 1. A transportation refrigerating apparatus which is driven by an engine together with a battery charging generator to control the temperature in a freezer by increasing or decreasing the number of revolutions of the engine. When the internal temperature of the freezer does not reach a predetermined temperature according to the number of revolutions of the engine after a predetermined time from the start of operation at a certain number of times, or the freezer after a predetermined time from the time when the engine is started at an arbitrary number of revolutions When the internal temperature does not reach a predetermined temperature according to the engine speed and the charging of the battery is completed, a control means for increasing the engine speed is provided. A refrigerating apparatus for transportation characterized by.