JPH1038411A - Freezing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely discharge a refrigerant fluid residing in a compressor without production of abnormal high pressure by setting the rotational speed of a clutch for coupling a clutch to rotate the compressor to the rotational speed of an engine during cell motor cranking. SOLUTION: Once an engine is started with a cell motor, the rotational speed of an engine rises with cranking by the cell motor, and a centrifugal clutch is coupled at the rotational speed of the engine during the rise of the speed of the engine and a compressor 6 is started in the state where a solenoid valve 68 for unloader 65 is opened. The compressor 6 after started is mildly rotated at a low speed, and when there exists a liquid refrigerant (refrigerant fluid) in the compressor 6, the refrigerant is mildly compressed with a piston 63 to be discharged into a discharge pipe 66. Thereafter, as the engine is ignited and started, the speeds of the engine and the compressor 6 simultaneously rise and hence operated at the set predetermined speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing an abnormally high pressure from being generated due to refrigerant liquid compression by a compressor in a refrigeration unit such as a refrigeration unit for land transportation.

[0002]

2. Description of the Related Art A refrigeration system for land transportation (hereinafter, abbreviated as a refrigeration system) is mainly installed on a truck, and performs cooling operation,
By performing a heating operation or the like, the internal temperature of the freezer mounted on the truck is maintained at a predetermined temperature.

FIGS. 3, 4, 5 and 6 show an example of such a refrigerating apparatus. FIG.
FIG. 3 is a rear view of the vehicle showing an installation state of the condensing unit, FIG. 3 is a plan view showing an outline of components of the condensing unit and an arrangement state thereof, and FIG. 4 is a front view thereof.

[0004] In FIG. 5, the refrigerating apparatus includes a freezer 1.
Condensing unit 1 installed at the lower part of the outside of 00
And the evaporator unit 30 installed in the freezer 100 is connected by a refrigerant pipe 40. As shown in FIG. 6, the condensing unit 1 (width L) is bolted to the lying side 101 attached to the lower part of the freezer 100 via a bracket 102 so that the front 1 a of the condensing unit 1 is freezer. 100 side 1
Suspended so as not to protrude outward from 00a.
The freezer 100 is fixedly installed on two chassis channels 103 (position S) of the truck.

The condensing unit 1 has an engine 5 inside a casing 2 as shown in FIGS.
(Length 1), a compressor 6 driven by the engine 5, an electric motor 7 for driving the compressor 6 by a commercial power supply, a condenser 8 and a radiator 9 for introducing outside air to drive a cooling fan 10 for cooling these. They are arranged with their axes parallel. The above casing 2
The front 2a has a suction port 3 and a suction port 4 for introducing outside air into the casing 2, and the back 2b has a discharge port 12 for discharging outside air flowing through the condenser 8 and the radiator 9.
Is provided.

The power of the engine 5 is supplied to the electric motor 7 via a centrifugal clutch 11 attached to the tip of the drive shaft.
And transmitted to the compressor 6 and the cooling fan 10. While the vehicle is running, the engine 5 is used, and the centrifugal clutch 11 is connected with the increase in the rotation speed of the engine 5, and the compressor 6 and the cooling fan 10 are driven. On the other hand, when the commercial power source can be used while the vehicle is stopped, the electric motor 7 is used, and the compressor 6 and the cooling fan 10 are driven by the electric motor 7. At this time, the centrifugal clutch 11 is in a disengaged state, so that the power of the electric motor is not transmitted to the engine 5.

As described above, when the compressor 6 is driven by the engine 5 or the electric motor 7, the high-pressure, high-temperature gas refrigerant compressed by the compressor 6 is sent to the condenser 8, where it is introduced by the cooling fan 10. It is cooled by the outside air and condensed and liquefied. This liquid refrigerant is sent to the evaporator unit 30 (see FIG. 5) via the refrigerant pipe 40 (see FIG. 5), where it cools the air in the freezer 100, and is evaporated and vaporized. Then, the gas refrigerant returns to the compressor 6 via the refrigerant pipe 40, and is compressed by the compressor 6.

On the other hand, when the cooling fan 10 is driven, outside air is introduced into the casing 2 through the suction ports 3 and 4, and flows through the condenser 8 and the radiator 9, where the compressor 6 To cool the high-pressure, high-temperature gas refrigerant discharged from the radiator 9
Then, the cooling water of the engine 5 is cooled and discharged from the outlet 12.

FIG. 7 shows a change in rotation speed when the compressor 6 is driven by the engine 5. When the engine 5 is started by a starter motor (not shown), the engine speed rises from point 0 to point (a) in the figure and rotates at a constant speed as shown by (b) → (b). Continue. When the engine 5 starts ignition at the point (b), the rotation speed increases to (c) and continues to rotate at this constant rotation speed.

[0010] As described above, the engine 5 is switched from (b) to (c).
Centrifugal clutch 11 attached to the engine shaft and rotating with the engine during acceleration.
Is connected at a point (d), the compressor 6 connected to the centrifugal clutch 11 and the belt starts to rotate, is accelerated together with the engine 5, and when the engine 5 reaches a certain speed at a certain rotation speed, the compressor 6 also becomes constant. Rotated at speed.

[0011]

In the above-mentioned conventional refrigeration system, the compressor 6 is accelerated during the acceleration of the engine 5 by the centrifugal clutch 11 being engaged at the point (d) of FIG. The speed becomes constant at points (c) and (c).
On the other hand, when the compressor 6 has been stopped for a long time, the refrigerant passing through the evaporator 30 and the condenser 8 may stay in the compressor 6 in a liquid state. In this state, when the clutch 11 is engaged at the above point (d) and the compressor 6 is started, the refrigerant is compressed in a liquid state, becomes an abnormally high pressure exceeding 100 KG / cm ² G, and the compressor 6 May be damaged.

At this time, the load torque of the compressor 6 becomes abnormally large, and when the engine is driven, it is forcibly driven by the engine 5 so that an excessive load is applied to the engine 5 and the electric motor 7 In the case of driving, the rotation speed of the motor 7 is reduced due to an excessive load on the compressor 6 side, and the electric motor 7 is stopped or damaged.

An object of the present invention is to reliably discharge a refrigerant liquid remaining in a compressor without observing the occurrence of an abnormally high pressure in the compressor.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a gist of the invention is to provide a compressor having an engine started by a starter motor and driven by the engine via a clutch. In the refrigeration unit comprising: the refrigeration unit, wherein the clutch operation speed for rotating the compressor by coupling the clutch is set to the engine speed during the starter motor cranking. is there.

According to the above-mentioned means, when the clutch is engaged to connect the engine and the compressor during the cranking of the starter motor and the compressor is started, the compressor is slowly and slowly rotated at a low speed by the torque of the starter motor. Gently compresses and discharges the refrigerant liquid that has accumulated in the liquid. Thereby, generation of an abnormally high pressure due to compression of the refrigerant liquid by the compressor is avoided.

Incidentally, even if an abnormally high pressure state is to be generated in the compressor, the starter motor is stopped at this initial stage. Therefore, by repeating the starter motor cranking, the refrigerant liquid can be reliably discharged.

According to a second aspect of the present invention, in addition to the above means, the compressor is a compressor with an unloader mechanism,
That is, the compressor is started in an unloader state.

According to such means, even if the refrigerant liquid stays in the compressor, the cylinder in the unloader state can
This can be gradually discharged with the rotation of the compressor without being compressed, and the generation of the abnormally high pressure and the generation of the excessive torque due to this are avoided.

Further, in the first means, it is a preferable specific means of the present invention that the fuel supply of the engine is started after a predetermined time after the engine is started by the starter motor.

According to such means, the operation time for discharging the refrigerant liquid by the starter cranking is extended,
The refrigerant liquid can be reliably discharged without increasing the pressure of the compressor.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a diagram showing an operation state of an engine and a compressor of a condensing unit according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of the compressor, and FIG.
FIG. 4 is a plan view showing a schematic arrangement of components of the condensing unit, and FIG. 4 is a front view thereof.

3 and 4, reference numeral 1 denotes a condensing unit. The condensing unit 1 includes an engine having a cell motor (not shown) in a casing 2 thereof, and a compressor 6 driven by the engine 5. An electric motor 7 for driving the compressor 6 by a commercial power supply and a cooling fan 10 for introducing outside air to the condenser 8 and the radiator 9 to cool them are arranged in parallel with their drive shafts. A suction port 3 and a suction port 4 for introducing outside air into the casing 2 are provided on a front surface 2a of the casing 2, and a discharge port 12 for discharging outside air flowing through a condenser 8 and a radiator 9 is provided on a back surface 2b. Have been.

The power of the engine 5 is supplied to the electric motor 7 via a centrifugal clutch 11 attached to the drive shaft.
And transmitted to the compressor 6 and the cooling fan 10. While the vehicle is running, the engine 5 is used, and the centrifugal clutch 11 is kept in a continuous state as the rotation speed of the engine 5 increases, and the compressor 6 and the cooling fan 10 are driven. On the other hand, when the commercial power supply can be used while the vehicle is stopped, the electric motor 7 is used.
Thereby, the compressor 6 and the cooling fan 10 are driven.
At this time, the centrifugal clutch 11 is in a disengaged state,
The power of the electric motor 7 is not transmitted to the engine 5.

As described above, when the compressor 6 is driven by the engine 5 or the electric motor 7, the high-pressure / high-temperature gas refrigerant compressed by the compressor 6 is sent to the condenser 8, where the cooling fan It is cooled by the outside air introduced by 10 and condensed and liquefied. This liquid refrigerant is sent to the evaporator unit 30 (see FIG. 5) through the refrigerant pipe 40 (see FIG. 4), where it is stored in the freezer 100.
Cools, evaporates and evaporates the air inside. Then, the gas refrigerant returns to the compressor 6 via the refrigerant pipe 40, and is compressed by the compressor 6.

On the other hand, when the cooling fan 10 is driven, outside air is introduced into the casing 2 through the suction ports 3 and 4, and flows through the condenser 8 and the radiator 9, where the compressor 6 To cool the high-pressure, high-temperature gas refrigerant discharged from the radiator 9
Then, the cooling water of the engine 5 is cooled and discharged from the outlet 12. The compressor 6 shown in FIG. 2 is a reciprocating compressor with an unloader. In FIG. 2, reference numeral 61 denotes a shaft connected to the engine 5 or the electric motor 7 via the clutch 11 (see FIGS. 6 to 7). Is a housing, 67 is a cylinder (two cylinders on this side), 63 is connected to the shaft 61, a piston reciprocated in the cylinder 67 by rotation of the shaft 61, 64 is a refrigerant suction pipe, and 66 is a discharge pipe. Tube.

Reference numeral 65 denotes an unloader provided between the cylinder 67 and the suction pipe 64. By opening and closing the solenoid valve 28, an unloader passage 69 between the cylinder 67 and the suction pipe 64 communicates or opens. It is designed to be shut off.

In the condensing unit, when the engine 5 rotates, the centrifugal clutch 11 is brought into contact and the shaft 61 of the compressor 6 is driven to rotate, the piston 63 reciprocates in the cylinder 67 and the suction pipe 64 moves. , And compresses the gas refrigerant to send it to the discharge pipe 66.

At this time, when the solenoid valve 68 of the unloader 65 is opened, the refrigerant gas in the cylinder 67 flows from the unloader passage 69 through the unloader 65 to the suction pipe 6.
4, the refrigerant gas in the cylinder 67 is not compressed. On the other hand, when the solenoid valve 28 is closed, the refrigerant gas is compressed by the piston 63 as described above.

In the operation state diagram of the engine 5 and the compressor 6 shown in FIG.
B indicates a change in the number of revolutions of the compressor 6, and when the engine 5 is started by a starter motor (not shown), the engine speed increases from point 0 to point (a) in the figure due to cranking by the starter motor. The centrifugal clutch 11 is engaged at a point (d) while the engine rotation is increasing due to the self-motor cranking, and the compressor 6 is started.

After startup, the compressor 6 is gently rotated at a low speed. When a liquid refrigerant (refrigerant liquid) is present in the compressor 6, it is gently compressed by the piston 63 and discharged to the discharge pipe 66. . (Point (a) → (b) in FIG. 1), thereby avoiding the occurrence of abnormally high pressure in the compressor 6 due to the compression of the refrigerant liquid.

Thereafter, when the engine 5 is ignited and started at the point (b), the rotations of the engine 5 and the compressor 6 simultaneously rise from the point (b) to the point (c), and when the rotation reaches the point (c). , The engine 5 and the compressor 6 are operated at a set constant rotation speed.

In the above operation, the compressor 6 starts rotating (started) at a point (d) at the time of cracking by the cell motor, but the unloader 65 of the compressor 6 is started.
When the compressor 6 is started in a state where the electromagnetic valve 68 is opened, the compression in the cylinder 67 equipped with the unloader 65 is not performed even if the refrigerant liquid stays in the compressor 6. This suppresses the generation of excessive torque from the compressor 6 even if the liquid refrigerant stays, thereby avoiding damage to the engine 5 or the compressor 6.

Further, even in the case where an abnormally high pressure state is about to occur in the compressor 6, the increase in the torque causes the stop of the starter motor, so that the starter in the process of 0 → (b) in FIG. If the startup is repeated, the refrigerant liquid staying in the compressor 6 can be reliably discharged.

In FIG. 1, the engine is accelerated from the point 0 to the point (a) by the starter motor.
After the compressor 6 is started at the point, both rotations are maintained at a constant rotational speed by the self-motor, as shown at the point (a) → (b), but the engine 5 is ignited and started at the point (a) (b). The time required to reach the point is not constant and varies.

In order to cope with this, in FIG. 1, the fuel injection of the engine 5 is delayed for a certain time ((b) → (b ′)) indicated by t from the start of the engine by the starter motor, and before the engine 5 is ignited. While driving the cell motor,
The centrifugal clutch 11 is set to be securely connected.
Thereby, even if the refrigerant liquid remains in the compressor 6, the compressor 6 can be slowly rotated by the cell motor for a longer period of time t than in the conventional case. The liquid can be discharged.

[0037]

According to the present invention, as described above, according to the present invention, by starting the compressor during the cell motor cranking, the compressor is slowly rotated at a low speed by the cell motor and stays in the compressor. Since the generated refrigerant liquid can be gently compressed and discharged, it is possible to prevent the occurrence of abnormally high pressure in the compressor, the damage of the compressor caused by this, and the damage of the engine or motor due to excessive torque.

According to the second aspect of the present invention, by setting the cylinder in the unloader state, the compressor can discharge the refrigerant liquid by its rotation with almost no compression, and the abnormally high pressure of the compressor. Is prevented from occurring.

According to the third aspect of the present invention, the operation time for discharging the refrigerant liquid based on the ranking of the starter motor is extended, and the occurrence of abnormally high pressure is prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operation state of an engine and a compressor of a refrigeration unit according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the compressor in the embodiment.

FIG. 3 is a plan view showing a schematic arrangement of equipment of a refrigeration unit to which the present invention is applied.

FIG. 4 is a front view in FIG. 3;

FIG. 5 is an overall equipment diagram of a vehicle equipped with a refrigeration unit.

FIG. 6 is a rear view showing an arrangement of a condensing unit in the vehicle.

FIG. 7 is a response diagram of FIG. 1 showing an operation state of a conventional refrigeration unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Condensing unit 5 Engine 6 Compressor 7 Electric motor 8 Condenser 11 Centrifugal clutch 30 Evaporator unit 63 Piston 65 Unloader 67 Cylinder

Claims (3)

[Claims] 1. A refrigeration unit comprising an engine started by a starter motor and a compressor driven by the engine via a clutch, wherein the refrigeration unit rotates the compressor by coupling the clutch. A refrigeration unit wherein the clutch operation speed is set to the engine speed during the starter cranking. 2. The refrigeration unit according to claim 1, wherein the compressor is a compressor with an unloader mechanism, and the compressor is started in an unloader state. 3. The refrigeration unit according to claim 1, wherein the refrigeration unit is configured to start supplying the fuel of the engine after a certain period of time after starting the engine with the starter motor.