JP2001330353A - Refrigerating device for transportation and refrigerating operation method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress supply of hot air. SOLUTION: Refrigerating operation through which refrigerant discharged by a compressor 6 is fed to the inlet side of an evaporator 7 through a condenser 14 and defrost operation through which a refrigerant discharged by the compressor 6 is fed to the inlet side of the evaporator 7 not through the condenser 14 are switched. During starting of the compressor 6, defrost operation is executed and when the compressor 6 effects desorption from an overload state, defrost operation is switched to refrigerating operation. A pressure balance occurs in a short time, a time of defrost operation is effectively shortened, and a supply time of hot air is also shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for transportation and a method of refrigeration operation of the refrigeration system for transportation, and more particularly, to an engine starting torque when a defrost operation is executed at the time of overload during thermo-operation control. TECHNICAL FIELD The present invention relates to a transport refrigeration apparatus and a refrigeration operation method for the transport refrigeration apparatus, which can prevent the amount of water from becoming excessive.

[0002]

2. Description of the Related Art An apparatus for land transportation comprises a self-propelled body such as a trailer or a truck and a freezer. As shown in FIG. 3, the refrigerating device attached to the freezer includes a condensing unit 101 and an evaporator unit 1.
02. Condensing unit 101
Is composed of a compressor 103 and a condenser 104. The evaporator unit 102 includes an evaporator 105. The condenser 104 is provided on a first refrigerant pipe 107 connecting the discharge side of the compressor 103 and the inlet side of the evaporator 105. The suction side of the compressor 103 and the outlet side of the evaporator 105 are connected by a second refrigerant pipe 108.

[0003] The freezer is maintained at a substantially constant temperature by thermo-operation control. In the thermo-operation control, the freezing operation is stopped when the freezer temperature falls below the set temperature, and the freezing operation is restarted when the freezer temperature exceeds the set temperature. When restarting the refrigeration operation, especially when restarting during overload operation,
Since the discharge side of the compressor 103 is in a high pressure state, the load on the compressor 103 increases, and the engine starting torque becomes excessive.

[0004] A technique for preventing such an excessive increase in the engine starting torque is known as shown in FIG.
The refrigeration unit operation controller 109 to which the restart command is input sends a signal to the defrost timer 110,
For a fixed time set in the defrost timer, the defrost operation controller 111 excites the capacitor inlet solenoid valve relay 112 and the defrost solenoid valve relay 116, closes the capacitor inlet solenoid valve 113, opens the defrost solenoid valve 114, The first refrigerant pipe 107 is shut off, and the third refrigerant pipe 115 extending from the discharge side of the compressor 103 to the inlet side of the evaporator 105 is opened. Third refrigerant pipe 1
15 constitutes a defrost circuit. Such a defrost circuit balances the high and low pressures in the defrost circuit which is a refrigerant circuit by releasing the discharge side pressure of the compressor 103 to the evaporator 105 side without passing through the condenser 104. Such an equilibrium
The restart torque of the compressor 103 is reduced to facilitate the start.

[0005] At the time of restarting while such a known thermo operation is continued, a defrost operation is performed for a fixed time by a timer regardless of the operating pressure condition of the refrigeration system.
In such a defrost operation, the gas refrigerant that has not been cooled by the condenser 104 is sent to the evaporator 105, and the temperature of the evaporator 105 rises rapidly, and warm air that exchanges heat with the evaporator 105 enters the freezer compartment in the freezing operation. It was blowing out every time it was restarted.

[0006] It is required that such blowing of warm air be reduced.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a transport refrigeration apparatus and a refrigeration operation method for the transport refrigeration apparatus, which can alleviate the blowing of warm air.

[0008]

Means for solving the problem are described as follows. The technical items appearing in the expression are appended with numbers, symbols, and the like in parentheses (). The numbers, symbols, and the like are technical items that constitute at least one embodiment or a plurality of the embodiments of the present invention, in particular, the embodiments or the examples. Corresponds to the reference numerals, reference symbols, and the like assigned to the technical matters expressed in the drawings corresponding to the above. Such reference numbers and reference symbols clarify the correspondence and bridging between the technical matters described in the claims and the technical matters of the embodiments or examples. Such correspondence / bridge does not mean that the technical matters described in the claims are interpreted as being limited to the technical matters of the embodiments or the examples.

A transport refrigeration system according to the present invention comprises a compressor (6), a condenser (14) disposed downstream of the compressor (6), and an evaporator (14) disposed downstream of the condenser (14). 7), a first pipe (8) from the compressor (6) via the condenser (14) to the inlet side of the evaporator (7), and an evaporator (7) without the condenser (14) from the compressor (6). The second pipe (11) heading toward the inlet of the compressor and the compressor (6) are connected to the first pipe (8) or the second pipe (11).
, A rotary drive system (23) for driving the compressor (6), a detector (24) for detecting the rotational speed of the rotary drive system (23), and a controller (26, 27). When the compressor (6) is started, the controller (26, 27) controls the compressor based on the first control for connecting the compressor 6 to the second pipe (11) and the increase in the rotation speed detected by the detector (24). Is connected to the first pipe (8).

Although the defrost operation is executed by the first control, the pressure equilibrium is realized within a short time, and the overload state is quickly eliminated. The controller (26, 27) includes an engine speed controller (26) and a defrost operation controller (27). The defrost operation controller (27) executes switching between the first control and the second control, and controls the engine speed. The number controller (26) provides a switching signal to the defrost operation controller (27) based on the increase in the rotation speed. The overload state can be determined based on the magnitude of the rotation speed (speed) of the compressor or the corresponding rotation speed of the engine with respect to the reference rotation speed. It is preferable that the increase rotation speed is a start-up confirmation rotation speed at which the rise of the rotation drive system (23) is confirmed. The start-up confirmation rotation speed is known as a rated rotation speed and an optimum rotation speed at which proper operation is constantly performed.

The method of refrigeration operation of the transport refrigeration system according to the present invention is to execute a refrigeration operation in which the refrigerant discharged from the compressor (6) is sent to the inlet side of the evaporator (7) via the condenser (14). 6) executing a defrost operation in which the refrigerant discharged from the evaporator (7) is sent to the inlet side of the evaporator (7) without passing through the condenser (14).
Executing the defrost operation when starting the compressor (6), and switching the defrost operation to the refrigeration operation when the compressor (6) leaves the overload state.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Corresponding to the drawings, in the embodiment of the transport refrigerating apparatus according to the present invention, a freezer is provided with a self-propelled vehicle body in the form of a truck. The freezer 1 is mounted on the self-propelled vehicle body 2 as shown in FIG. The internal space of the freezer is cooled by a freezer.
The refrigeration apparatus includes a condensing unit 3, an evaporator unit 4, and a refrigerant pipe 5. The condensing unit 3 is hung and supported by a vehicle chassis arranged below the self-propelled vehicle body 2, and is arranged at a position where the condensing unit 3 easily comes into contact with external air.
The refrigerant pipe 5 is a pipe for circulating the refrigerant between the condensing unit 3 and the evaporator unit 4.

The condensing unit 3 has a compressor 6 as shown in FIG. The evaporator unit 4 includes an evaporator 7. The refrigerant pipe 5 includes a first circulation pipe feed section 8, a first circulation pipe return section 9, a second circulation pipe feed section 11, and a second circulation pipe return section 12. Second circulation pipe return part 1
2 is also used as the first circulation pipe return portion 9. First
The circulation pipe feed portion 8 is a pipe connecting the discharge side of the compressor 6 to the inlet side of the evaporator 7 of the evaporator unit 4. The first circulation pipe return portion 9 connects the outlet side of the evaporator 7 of the evaporator unit 4 to the compressor 6.
This is a pipe connected to the suction side.

The first circulation pipe feed section 8 and the second circulation pipe feed section 11 are connected in parallel between the compressor 6 and the evaporator unit 4. For the parallelization, a first branch joint 13 is provided on the discharge side of the compressor 6. The condenser 14 is interposed between the first branch joint 13 and the evaporator unit 4 in the first circulation pipe feed portion 8. A condenser inlet side solenoid valve 15 is interposed between the first branch joint 13 and the condenser 14 in the first circulation pipe feed portion 8. The condenser 14 is interposed between the condenser inlet-side electromagnetic valve 15 and the inlet side of the evaporator 7.

A defrost solenoid valve 16 is provided in the second circulation pipe feed portion 11 between the first branch joint 13 and the inlet side of the evaporator 7. Capacitor inlet side solenoid valve 1
5 and the defrost solenoid valve 16 can be formed by one three-way switching valve. Condenser 14 and evaporator 7
A receiver 17 and a dryer 18 are interposed in series in the first circulation pipe feed portion 8 between the inlet side and the inlet side. First
The circulation pipe feed portion 8 and the second circulation pipe feed portion 11
The second branch joint 19 is connected to the inlet side of the evaporator 7. An expansion valve 21 is interposed between the dryer 18 and the second branch joint 19 in the first circulation pipe feed portion 8. An accumulator 22 is provided in the first circulation pipe return portion 9 between the outlet side of the evaporator 7 and the suction side of the compressor 6. The compressor 6 is the engine 2
3 driven. The rotation speed of the engine 23 is detected by a rotation speed detector 24.

The thermo-operation control system includes a refrigeration unit operation controller 25, an engine speed controller 26,
A defrost operation controller 27, a condenser inlet solenoid valve relay 28, and a defrost solenoid valve relay 29 are provided. The refrigeration unit operation controller 25 includes:
It is connected to an engine speed controller 26. The engine speed controller 26 is connected to a defrost operation controller 27. The defrost operation controller 27 is connected in parallel to a condenser inlet solenoid valve relay 28 and a defrost solenoid valve relay 29. The rotation speed detector 24 outputs a rotation speed corresponding signal 31 corresponding to the rotation speed of the engine 23. The rotation speed corresponding signal 31 is input to the engine rotation speed controller 26.

When the compressor 6 of the condensing unit 3 is started by driving of the engine 23, the condenser inlet side solenoid valve 15 is opened, the defrost solenoid valve 16 is closed, and the second circulation pipe feed portion 11 is shut off. The high-temperature, high-pressure refrigerant gas compressed by the compressor 6 is sent to the condenser 14, where it is cooled by outside air, which is the air outside the vehicle, and condensed and liquefied. The refrigerant liquid condensed and liquefied in this way is passed through the first circulation pipe feed portion 8 and sent from the condenser 14 to the evaporator unit 4 via the receiver 17 and the dryer 18. The refrigerant sent to the evaporator unit 4 in this way is the evaporator unit 4
Adiabatic expansion through the expansion valve 21.

The gas refrigerant expanded in this manner exchanges heat with the circulating air in the freezer flowing on the outer surface of the evaporator 7 by the evaporator fan (not shown) while passing through the evaporator 7. The circulating air cooled by the heat exchange is blown into the freezer by the evaporator fan. The refrigerant evaporated and vaporized by exchanging heat with the circulating air in the evaporator 7 returns to the suction side of the compressor 6 via the accumulator 22 through the first circulation pipe return portion 9.

When the temperature in the freezer falls below the first set temperature, the compressor 6 is stopped based on a signal output from a temperature detection device (not shown) disposed in the freezer, and the operation of the freezer is performed. Pauses. The freezer temperature is second
When the temperature becomes equal to or higher than the set temperature, the compressor 6 is restarted and the refrigeration apparatus operates. At the time of this restart, especially when restarting during the overload operation, the compressor 6 is restarted while the discharge side of the compressor 6 is at a high pressure,
The load of the compressor 6 is improperly large and the engine 23
Starting torque becomes inappropriately large.

If the thermo-operation is started during the freezing operation,
The refrigeration unit operation controller 25 to which the restart signal output from the temperature detection device is input outputs a signal 41 indicating the restart to the engine speed controller 26.
The engine speed controller 26 outputs a defrost operation start signal 42 to the defrost operation controller 27 based on the signal 41. The defrost operation controller 27 transmits the first excitation signal 43 to the condenser inlet electromagnetic valve relay 28 and the defrost electromagnetic valve relay 29 based on the defrost operation start signal 42.

The excitation based on the first excitation signal 43 closes the condenser inlet side solenoid valve 15 and causes the defrost solenoid valve 1
6 opens. The refrigerant gas discharged from the compressor 6 is
The first branch joint 13 passes through the defrost solenoid valve 16, passes through the second circulation pipe feed section 11, and passes through the second branch joint 19.
And enters the evaporator 7 via. The gas refrigerant that has entered the evaporator 7 is decompressed in the evaporator 7 that still maintains a temperature as low as the second set temperature, and the pressure is balanced, so that the overload of the compressor 6 is reduced.

With this relaxation, the engine speed of the engine 23 suddenly increases. Engine 2 growing like this
The engine speed of No. 3 quickly reaches the set speed (example: engine startup confirmation speed). The rotation speed detector 24 outputs a rotation speed corresponding signal 31 corresponding to the arrival to the engine speed controller 26. The engine speed controller 26 to which the speed corresponding signal 31 has been input outputs a defrost operation stop signal 44 to the defrost operation controller 27. The defrost operation controller 27 receives the defrost operation stop signal 44,
The second excitation signal 45 is transmitted to the capacitor inlet solenoid valve relay 28 and the defrost solenoid valve relay 29. Excitation based on the second excitation signal 45 causes the capacitor inlet side solenoid valve 1
5, the defrost solenoid valve 16 is closed, the defrost operation is interrupted, and the refrigeration operation is restarted.

As described above, the refrigerant pressure balance of the refrigeration system at the time of restart is quickly realized, the overload state is quickly eliminated, and the proper steady-state refrigeration operation returns within a short time. The defrost operation time is reduced, and the amount of warm air blown into the freezer is minimized.

[0024]

According to the transport refrigerating apparatus and the refrigerating operation method of the transport refrigerating apparatus of the present invention, the blowing of warm air is effectively suppressed.

[Brief description of the drawings]

FIG. 1 is an axial projection view showing an embodiment of a transport refrigeration apparatus according to the present invention.

FIG. 2 is a circuit diagram showing an embodiment of a transport refrigeration apparatus according to the present invention.

FIG. 3 is a circuit diagram showing a known device.

[Explanation of symbols]

 Reference Signs List 6 compressor 7 evaporator 8 first pipe 11 second pipe 13 branch joint 14 condenser 15 first valve 16 second valve 23 rotary drive system 24 detector 26, 27 controller 26 engine Speed controller 27 ... Defrost operation controller

Claims (5)

[Claims] A compressor disposed on a downstream side of the compressor; an evaporator disposed on a downstream side of the condenser; and a condenser heading from the compressor to an inlet side of the evaporator via the condenser. 1 pipe, a second pipe from the compressor to the inlet side of the evaporator without passing through the condenser, a valve for switching and connecting the compressor to the first pipe or the second pipe, and a rotation for driving the compressor. A drive system, a detector for detecting the number of rotations of the rotary drive system, and a controller, wherein the controller is configured to perform a first control for connecting the compressor to the second pipe when the compressor is started; A second control for connecting the compressor to the first pipe based on an increase in the detected rotational speed; To run transport refrigeration system. 2. The engine according to claim 1, wherein the controller includes an engine speed controller and a defrost operation controller, wherein the defrost operation controller executes switching between the first control and the second control. A transport refrigeration device that provides the switching signal to the defrost operation controller based on the increase in the rotational speed. 3. The transport refrigeration system according to claim 2, wherein the increased rotation speed is a startup confirmation rotation speed at which a rise of the rotation drive system is confirmed. 4. A refrigeration operation in which the refrigerant discharged from the compressor is sent to the inlet side of the evaporator via the condenser, and a defrost operation in which the refrigerant discharged from the compressor is sent to the inlet side of the evaporator without passing through the condenser. A refrigeration operation method for a transport refrigeration system, comprising: performing the defrost operation when the compressor is started; and switching the defrost operation to the refrigeration operation when the compressor leaves the overload state. 5. The refrigeration operation method for a transport refrigeration system according to claim 4, wherein the overload state is that the rotation speed of the compressor is higher than a set rotation speed.