JPH10197123A - Refrigeration device for transportation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise of an engine and a compressor by a method wherein an operation of an engine is changed over to a low speed operation when a deviation of an outdoor temperature from a set outdoor temperature is a predetermined value or lower. SOLUTION: A detected temperature of an outdoor temperature sensor 31 is inputted to a high speed and a low speed determining means 40, a set outdoor temperature set by an outdoor temperature setting means 45 arranged at a control device 60 is inputted to a high speed and low speed determining means 40 through a switch 45a and at the same time an in-refrigerator set temperature set by an in-refrigerator temperature setting means 46 is inputted to the high speed and low speed determining means 40 through a switch 46a. Then, the high speed and low speed determining means 40 changes over an operation of an engine to a low speed operation when a deviation of an outdoor temperature detected by the outdoor temperature sensor 31 from a set outdoor temperature set by an outdoor temperature setting means 45 is a predetermined value or lower in the case that the switch 45a is closed. Accordingly, it is possible to reduce noise of the engine and the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport refrigeration system used to maintain the temperature of a freezer mounted on a truck or the like at a target temperature.

[0002]

2. Description of the Related Art A system diagram of a conventional transport refrigeration system is shown in FIG. The engine 1 includes a high-speed solenoid 50 and a low-speed solenoid 51, and rotates at high speed when the high-speed solenoid 50 is selected, and rotates at low speed when the low-speed solenoid 51 is selected.

When the rotation speed of the engine 1 increases and reaches a predetermined rotation speed, the centrifugal clutch 4 is engaged and the compressor 3 is driven. The gas refrigerant discharged from the compressor 3 enters the condenser 6 through the three-way valve 52 as shown by a solid line arrow, and condenses by radiating heat to the outside air blown by the fan 7 driven by the motor 8. Liquefy.

[0004] After the liquid refrigerant is adiabatically expanded by being throttled by the throttle 9, it enters an evaporator 10 disposed in a freezer 54, where the air inside the refrigerator blown by a fan 11 driven by a motor 12 is provided. Is cooled to evaporate and return to the compressor 3.

During the heating operation, the three-way valve 52 is switched as shown by a broken line, and the refrigerant discharged from the compressor 3 enters the evaporator 10 through the three-way valve 52 as shown by a broken arrow.
Here, after the inside air is heated, the process returns to the compressor 3.

When a truck is parked at a cargo collection / delivery site, the motor 2 is driven by a current supplied from a commercial power supply.
Is driven. Then, the centrifugal clutch 4 is disengaged, and the compressor 3 is driven by the motor 2.

FIG. 4 shows a conventional control system diagram, and FIG. 5A shows an operation pattern when automatic start / stop is selected.
(B) shows an operation pattern when the continuous operation is selected.

When automatic start / stop is selected by the engine operation pattern changeover switch 33 at the time of cooling operation of the refrigeration system, that is, at the time of pull-down, a signal from the automatic start / stop is received, and the control unit receives the signal.
The automatic start / stop / continuous operation determination means 60 determines the automatic start / stop of the engine 1.

On the other hand, the target temperature Ts set by the internal temperature setting unit 30 and the internal temperature Ta detected by the internal temperature sensor 31 are determined by the high / low speed determining means 40 of the control device 60 and the heating / cooling / stopping determination. It is input to the means 41.

When the internal temperature Ta> the target temperature Ts + 0.5 ° C., as shown in FIG. 5A, the high / low speed determining means 40 determines the high speed operation of the engine 1, and determines whether the heating / heating operation is to be performed. cooling·
The stop determining means 41 determines a cooling operation of the refrigeration apparatus.

These determinations are made via the output means 43 via the high speed solenoid 50, the low speed solenoid 51 and the three-way valve of the engine 1.
52, the high-speed solenoid 50 is turned on, the low-speed solenoid 51 is turned off, and the three-way valve 52 is turned off. As a result, the engine 1 rotates at a high speed, and the three-way valve 52 is switched as shown by a solid line. High-speed cooling operation is performed.

By continuing this high-speed cooling operation for a while, the internal temperature Ta decreases, and when Ts + 0.5>Ta> Ts−1, the high-speed / low-speed determining means 40 determines the low-speed operation of the engine 1. The refrigeration system is in a low-speed cooling operation.

Further, when the internal temperature Ta decreases, Ts
When −1>Ta> Ts−3.5, the heating / cooling / stop determining means 41 determines to stop the refrigeration apparatus, and the refrigeration apparatus stops.

When the internal temperature Ta further decreases and becomes Ts−3.5> Ta, the high / low speed determining means 40 determines the high speed operation of the engine 1, and the heating / cooling / stop determining means 41 performs the heating operation, that is, the heating operation. Since the pull-up operation is determined, the refrigeration system is set to the high-speed heating operation.

When the internal temperature Ta rises due to this high-speed heating operation and Ts + 1.5>Ta> Ts−1, the refrigeration system stops. When Ts + 4>Ta> Ts + 1.5, the refrigeration system operates in a low-speed cooling operation. When Ta> Ts + 4, high-speed cooling operation is performed.

When continuous operation is selected by the engine operation pattern changeover switch 33, as shown in FIG. 5B, during pull-down, high-speed cooling operation is performed when Ta> Ts + 0.5, and Ts + 0.5>Ta> Ts. When -1, low-speed cooling operation, Ts-1
When> Ta, high-speed heating operation is performed.

At the time of pull-up, Ts + 4>Ta> Ts + 1.5
When, the low-speed cooling operation is performed, and when Ta> Ts + 4, the high-speed cooling operation is performed.

[0018]

In the above-mentioned conventional refrigeration system, when the deviation between the internal temperature and the target temperature is equal to or larger than a predetermined deviation (for example, Ta> Ts + 0.5 when pulling down, Ta <Ts when pulling up). -1) Since the engine 1 and the compressor 3 are operated at high speed, there is a problem that noise is large.

[0019]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the first invention is that it is driven by an engine capable of switching between high speed and low speed. When the difference between the internal temperature and the target temperature is equal to or more than a predetermined deviation, the transport refrigeration system that operates the engine at a high speed is provided with an external air temperature sensor and an external air temperature setting means. Even when the deviation from the target temperature is equal to or greater than a predetermined deviation, when the deviation between the outside air temperature detected by the outside air temperature sensor and the outside air set temperature set by the outside air temperature setting means is equal to or less than a predetermined value, the engine is operated at a low speed. A transport refrigeration system characterized in that a means for switching to operation is provided.

Another feature is that a switch for arbitrarily selecting the switching operation by the outside air temperature sensor and the outside air temperature setting means is provided.

The gist of the second invention is to provide a compressor driven by an engine capable of switching between high speed and low speed, and when the deviation between the internal temperature and the target temperature is equal to or greater than a predetermined deviation, the engine is switched on. In a transport refrigeration apparatus that operates at high speed, the internal temperature setting means is provided and the internal set temperature set by the internal temperature setting means is provided even when the deviation between the internal temperature and the target temperature is equal to or greater than a predetermined deviation. A means for switching the engine to low-speed operation when a deviation between the engine and the target temperature is equal to or less than a predetermined value.

Another feature is that a switch for arbitrarily selecting the switching operation by the above-mentioned internal temperature setting means is provided.

[0023]

1 and 2 show an embodiment of the present invention.
FIG. 1 shows a control system diagram, FIG. 2A shows an operation pattern when automatic start / stop is selected, and FIG. 2B shows an operation pattern when continuous operation is selected. . The configuration of the refrigerating apparatus is the same as that of the conventional one shown in FIG.

As shown in FIG. 1, an outside air temperature sensor 31 is provided, and the detected temperature To is input to a high speed / low speed determining means 40. Further, the control device 60 is provided with an outside air temperature setting means 45 and an inside temperature setting means 46, and the outside air set temperatures Toc and Toh set by the outside air temperature setting means 45 are controlled by a switch 45.
a to the high-speed / low-speed determination means 40 and set by the internal temperature setting means 46a.
h is input to the high / low speed determining means 40 via the switch 46a.

When the cooling operation of the refrigerating apparatus is started by selecting automatic start / stop by the engine operation pattern changeover switch 33, the inside temperature Ta detected by the inside temperature sensor 32 is set by the inside temperature setter 30. Target temperature Ts + 0.5
If the temperature is not lower than ° C., the heating / cooling / stop determining means 41 determines the cooling operation as shown in FIG. When the switch 45a is closed, the outside air set temperature Toc set by the outside air temperature setting means 45 is input to the high speed / low speed determination means 40 via the switch 45a, where the outside air temperature sensor 31
Is compared with the detected outside air temperature To. The high / low speed determining means 40 determines the low speed operation of the engine 1 when Toc ≧ To, and determines the high speed operation of the engine 1 when Toc <To.

When the switch 46a is closed, the internal setting temperature Thc set by the internal temperature setting means 46 is input to the high / low speed determining means 40 via the switch 46a.
Here, the target temperature Ts set by the internal temperature setter 30
Is compared to The high / low speed determining means 40 determines the low speed operation of the engine 1 when Thc ≦ Ts, and determines the high speed operation of the engine 1 when Thc> Ts.

When the switches 45a and 46a are open, the high / low speed determining means 40 is the same as the conventional one,
The detected temperature Ta of 32 is compared with the target temperature Ts set by the internal temperature setting device 30, and if Ta> Ts + 0.5 ° C., the high-speed operation of the engine 1 is determined.

Thus, when the deviation between the internal temperature Ta and the target temperature Ts is equal to or larger than the predetermined deviation 0.5 ° C., the switches 45a and / or 46
When a is closed, high-speed / low-speed switching cooling operation is performed, and when switch 45a is closed, the outside air temperature To ≦ the set outside air temperature Toc
In this case, and when the switch 46a is closed, the engine 1 operates at a low speed when the target temperature Ts ≧ the set temperature Thc in the refrigerator, so that the noise of the engine 1 and the compressor 3 can be reduced.

The internal temperature Ta drops and Ts-1 <Ta <Ts + 0.
5, the refrigeration system starts low-speed cooling operation, and Ts-1> Ta
Stopping when> Ts-3.5 is the same as the conventional one, but when Ts-3.5> Ta, high-speed / low-speed switching heating operation is performed.

In the high-speed / low-speed switching heating operation, the switch
When 45a is closed, the outside air set temperature Toh set in the outside air temperature setting means 45 is input to the high speed / low speed determination means 40 via the switch 45a, and the outside air temperature To detected by the outside air temperature sensor 31 and here. Be compared. High / low speed determination means
40 determines the low speed operation of the engine 1 when Toh ≦ To, and determines the high speed operation of the engine 1 when Toh> To.

When the switch 46a is closed, the set temperature Thh set in the internal temperature setting means 46 is input to the high / low speed determining means 40 via the switch 46a, and the internal temperature is set here. The target temperature Ts set by the setting device 30 is compared with the target temperature Ts. The high / low speed determining means 40 determines the low speed operation of the engine 1 when Thh ≦ Ts, and determines the high speed operation of the engine 1 when Thh> Ts.

The internal temperature Ta rises and Ts-1 <Ta <Ts + 1.5
Then, the refrigerating apparatus is stopped, and when Ts + 1.5 <Ta <Ts + 4, the low-speed cooling operation is performed, and when Ta> Ts + 4, the high-speed / low-speed switching cooling operation is performed.

When continuous operation is selected by the engine operation pattern changeover switch 33, as shown in FIG. 2B, high-speed operation is performed when Ta> Ts + 0.5 at the time of pull-down.
A low-speed switching cooling operation is performed. When Ts + 0.5>Ta> Ts−1, a low-speed cooling operation is performed. When Ta <Ts−1, a high-speed / low-speed switching heating operation is performed.

At the time of pull-up, a high-speed / low-speed switching heating operation is performed when Ta <Ts + 1.5, a low-speed cooling operation is performed when Ts + 1.5 <Ta <Ts + 4, and a high-speed / low-speed switching cooling operation is performed when Ta> Ts + 4.

In the above embodiment, the operation pattern of the engine 1 is determined by the automatic start / stop / continuous operation determination means 42 by operating the engine operation pattern changeover switch 33. It is possible to always operate in one of the operation patterns of automatic start / stop and continuous operation.

Further, a predetermined deviation 0.5 between the internal temperature Ta for switching the operation pattern of the refrigeration system and the target temperature Ts.
, -1, -3.5, etc. can be arbitrarily determined. In addition, one of the switches 45a and 46a can be normally opened, and when the deviation between the outside air temperature To and the outside air set temperature Toc and Toh is equal to or less than a predetermined value, and / or the target temperature Ts and the inside set temperature When the deviation from Thc and Thh is equal to or less than a predetermined value, the engine 1 can be switched to low-speed operation.

[0037]

According to the first aspect of the present invention,
Even when the deviation between the inside temperature and the target temperature is equal to or greater than a predetermined deviation, when the deviation between the outside air temperature detected by the outside air temperature sensor and the outside air set temperature set by the outside air temperature setting means is equal to or less than a predetermined value, the engine is started. Since the operation can be switched to the low-speed operation, the noise of the engine and the compressor can be reduced.

A switch for arbitrarily selecting the switching operation by the outside air temperature sensor and the outside air temperature setting means is provided. When this switch is opened, the engine operates at high speed when the deviation between the internal temperature and the target temperature is equal to or larger than a predetermined deviation. Can drive.

According to the second aspect of the present invention, even when the deviation between the internal temperature and the target temperature is equal to or larger than a predetermined deviation,
When the deviation between the set temperature in the refrigerator set by the refrigerator temperature setting means and the target temperature is equal to or less than a predetermined value, the engine can be switched to the low-speed operation, so that the noise of the engine and the compressor can be reduced.

If a switch for arbitrarily selecting the switching operation by the internal temperature setting means is provided and this switch is opened, the engine can be operated at high speed when the deviation between the internal temperature and the target temperature is equal to or larger than a predetermined deviation. .

[Brief description of the drawings]

FIG. 1 is a control system diagram showing an embodiment of the present invention.

FIG. 2 shows an operation pattern of the refrigeration apparatus according to the embodiment, wherein (A) shows a case where automatic start / stop is selected, and (B) shows a case where continuous operation is selected.

FIG. 3 is a system diagram of a conventional transport refrigeration system.

FIG. 4 is a control system diagram of a conventional transport refrigeration system.

FIG. 5 shows an operation pattern of a conventional transport refrigeration system,
(A) shows the case where automatic start / stop is selected, and (B) shows the case where continuous operation is selected.

Claims (4)

[Claims] 1. A transport refrigeration system comprising a compressor driven by an engine capable of switching between a high speed and a low speed, wherein the engine is operated at a high speed when a deviation between the internal temperature and a target temperature is equal to or greater than a predetermined deviation. Even when the outside temperature sensor and the outside temperature setting means are provided and the deviation between the inside temperature and the target temperature is equal to or larger than a predetermined deviation,
Transporting means for switching the engine to low-speed operation when a deviation between an outside air temperature detected by the outside air temperature sensor and an outside air set temperature set by the outside air setting means is equal to or less than a predetermined value. For refrigeration equipment. 2. A transport refrigeration system according to claim 1, further comprising a switch for arbitrarily selecting a switching operation by said outside air temperature sensor and said outside air temperature setting means. 3. A transport refrigeration system comprising a compressor driven by an engine capable of switching between a high speed and a low speed, wherein the engine operates at a high speed when the deviation between the internal temperature and the target temperature is equal to or greater than a predetermined deviation. Even when the internal temperature setting means is provided and the deviation between the internal temperature and the target temperature is equal to or greater than a predetermined deviation, the deviation between the internal temperature set by the internal temperature setting means and the target temperature is set to a predetermined value. A means for switching the engine to low-speed operation when the value is equal to or less than a value is provided. 4. The transport refrigeration system according to claim 2, further comprising a switch for arbitrarily selecting a switching operation by said internal temperature setting means.