JP6957661B2 - Sub-engine type transportation refrigeration unit and vehicle - Google Patents

Description

The present invention relates to a sub-engine type transport refrigeration unit and a vehicle .

One of the transport refrigerating units mounted on a freezing vehicle, a freezing trailer, etc. is a sub-engine type transport refrigerating unit equipped with a dedicated sub-engine as a power source. Such a sub-engine includes an intake pipe having an intake port, and supplies the air sucked from the intake port to the sub-engine as combustion air.
Patent Document 1 discloses a container refrigerating device that is attached to a freight container for transportation and operates a refrigerating device by the driving force of a dedicated diesel engine. In this container refrigeration system, the air outside the container refrigeration system is supplied to the diesel engine.

Japanese Unexamined Patent Publication No. 62-91773

However, in the container refrigerating apparatus of Patent Document 1, since the air supplied to the diesel engine that drives the refrigerating apparatus is introduced from the outside of the container refrigerating apparatus, the influence of the transport ship or the transport vehicle on which the container refrigerating apparatus is mounted is affected. There was a possibility of introducing air that received (for example, exhaust heat of a traveling engine) and supplying it to a diesel engine. Since the temperature and pressure of the air affected by the transport ship and the transport vehicle are likely to change depending on the condition of the transport ship and the transport vehicle, the pressure and temperature of the air supplied to the diesel engine may not be stable. ..

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a sub-engine type transport refrigeration unit and a vehicle capable of supplying air having a stable pressure and temperature to a sub-engine. do.

In order to solve the above problems, the sub-engine type transportation refrigeration unit and the vehicle of the present invention employ the following means.
That is, the sub-engine type transport refrigeration unit according to one aspect of the present invention is a sub-engine for driving a compressor having an engine main body and an intake pipe connected to the engine main body and supplying air to the engine main body. includes pre Symbol a housing to house the Sabuenji down, and wherein the housing, the partition wall separating the other space where the engine body and the engine room where the engine body is installed is not installed vertically provided The intake pipe has an intake port that opens to the other space side.

In the above configuration, the intake port of the intake pipe that sends air to the engine body of the sub engine is open to the heat exchange room. As a result, the air in the heat exchange room can be taken in from the intake port and sent to the engine body of the sub engine via the intake pipe. Since the heat exchange room is separated from the space where the engine body is provided by a partition wall, it is not easily affected by the exhaust heat from the engine body whose temperature and pressure change according to the degree of output of the sub engine, and heat. The pressure and temperature of the air in the mating room are stable. Further, since the space where the engine body is provided is separated by a partition wall, the pressure fluctuation due to the vibration of the engine body does not occur in the heat exchange chamber, and the pressure is stable. As described above, in the above configuration, the pressure and temperature of the air in the heat exchange chamber are stabilized, so that the air having a stable pressure and temperature can be supplied to the engine body of the sub engine from the intake port. Therefore, it is possible to suppress the vibration of the sub-engine due to the intake pressure pulsation caused by the fluctuation of the pressure and temperature of the air supplied to the engine body. Further, since the vibration of the panels generated due to the vibration of the sub engine can be suppressed, the noise caused by the vibration of the panels can be suppressed.
Further, it is possible to realize a configuration in which the vibration of the sub-engine is suppressed without using any parts other than the parts of the existing sub-engine type transportation refrigeration unit.

Further, for example, when the traveling engine is arranged at the lower part of the vehicle and the heat exchange room is located above the engine room, the heat exchange room is located above the engine room and at a distance from the traveling engine. Therefore, it is not easily affected by the exhaust heat of the traveling engine, and the pressure and temperature of the air in the heat exchange room are stable. Therefore, it is possible to suppress the vibration of the sub-engine due to the intake pressure pulsation caused by the fluctuation of the pressure and temperature of the air supplied to the engine body. Further, since the vibration of the panels generated due to the vibration of the sub engine can be suppressed, the noise caused by the vibration of the panels can be suppressed.

Further, in the sub-engine type transport refrigeration unit according to one aspect of the present invention, the engine room is located below the other space , the intake pipe is provided with an air cleaner, and the air cleaner is arranged in the engine room. It may have been done.

In the above configuration, the air cleaner is arranged in the engine room located below the heat exchange room. Therefore, even when the sub-engine type transport refrigerating unit is located high above the ground, it is possible to easily inspect the air cleaner and replace the elements of the air cleaner. Therefore, the maintainability of the air cleaner can be improved.

Further, the sub-engine type transport refrigerating unit according to one aspect of the present invention may be provided in the housing and may include a fan for introducing outside air into the other space.

In the above configuration, the outside air is introduced into the heat exchange room by the fan. Therefore, relatively low temperature air equivalent to the outside air can be supplied to the engine body of the sub engine from the intake port. Therefore, it is possible to prevent a decrease in the output of the sub engine due to an increase in the intake air temperature.
Further, since the outside air is introduced into the heat exchange room by the fan, the pressure in the heat exchange room is kept constant. Therefore, it is possible to supply air with a stable pressure to the engine body.
Further, for example, when the sub-engine type transportation freezing unit is arranged above the cabin, which is applied to a vehicle having a cabin, outside air can be introduced into the heat exchange room without being blocked by the cabin. Therefore, it is possible to easily introduce outside air into the sub-engine type transportation refrigeration unit. In addition, the configuration can easily introduce air that is not affected by the vehicle.

Further, when the sub-engine type transport refrigeration unit according to one aspect of the present invention is installed in a vehicle, the fan may be provided on the front side of the vehicle in the housing.

In the above configuration, the fan is provided on the front side of the housing. Therefore, when introducing the outside air from the front to the rear of the vehicle (for example, the vehicle running wind) into the heat exchange room, the ram pressure can be used, and the outside air can be suitably introduced into the heat exchange room. can.

Further, in the sub-engine type transport refrigerating unit according to one aspect of the present invention, the intake port may be opened at a position avoiding the mainstream of the outside air introduced into the other space from the fan.

In the above configuration, the intake port is opened at a position avoiding the mainstream of the outside air introduced into the heat exchange room from the fan. Therefore, it is difficult for rainwater, dust, sand, etc. contained in the outside air introduced in the heat exchange room to be directly introduced into the intake pipe from the intake port. Therefore, it is possible to prevent foreign matter other than air from being introduced into the engine body of the sub-engine via the intake pipe.

Further, in the sub-engine type transport refrigerating unit according to one aspect of the present invention, the intake port may be opened downward.

Rainwater and dust contained in the outside air introduced from the fan into the heat exchange room flow from the top to the bottom due to gravity. In the above configuration, since the intake port is open downward, it is difficult for rainwater, dust, sand, etc. contained in the outside air introduced into the heat exchange room to be directly introduced into the intake pipe from the intake port. Further, even when rainwater, dust, sand, etc. flow into the heat exchange room from other than the fan, it is difficult for rainwater, dust, etc. to be directly introduced from the intake port opened downward. Therefore, it is possible to prevent foreign matter other than air from being introduced into the engine body of the sub-engine via the intake pipe.

Further, in the sub-engine type transport refrigerating unit according to one aspect of the present invention, the intake port may be opened in the downstream direction of the mainstream.

In the above configuration, the intake port opens from the fan in the downstream direction of the mainstream of the outside air introduced into the heat exchange room. Therefore, since the introduced outside air is not directly introduced into the intake port, it is difficult for rainwater, dust, sand, etc. contained in the outside air introduced in the heat exchange room to be directly introduced into the intake pipe from the intake port. Therefore, it is possible to prevent foreign matter other than air from being introduced into the engine body of the sub-engine via the intake pipe.
The vehicle according to one aspect of the present invention includes the sub-engine type transport refrigeration unit according to any one of the above.

According to the present invention, air having a stable pressure and temperature can be supplied to the sub engine.

It is a side view of the vehicle to which the refrigerating unit which concerns on embodiment of this invention is applied. It is a top view of the vehicle of FIG. It is a schematic vertical sectional view of the freezing unit for transportation of FIG. It is a front schematic view which shows the inside of the freezing unit for transportation of FIG. FIG. 4 is a cross-sectional view taken along the line AA of FIG. It is an enlarged view of the main part of this embodiment.

Hereinafter, embodiments of the sub-engine type transport refrigeration unit and the vehicle according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, in the vehicle 2 on which the refrigeration unit (sub-engine type transportation refrigeration unit) 1 according to the present embodiment is mounted, the traveling engine 31 is arranged below the cabin 3, so-called. It is a cab-over type transportation truck. The trailer van body 5 is mounted on a frame 4 extending in the front-rear direction behind the cabin 3. The trailer van body 5 is arranged so that the front surface is separated from the rear surface of the cabin 3, and a load such as a frozen / refrigerated product is loaded inside.

A refrigerating unit 1 is provided on the front surface of the trailer van body 5 over substantially the entire width direction of the vehicle. The refrigerating unit 1 is formed to have a short length in the front-rear direction so as not to affect the volume of the trailer van body 5. Further, the front surface of the refrigerating unit 1 is curved so that the length in the front-rear direction becomes shorter from the center in the vehicle width direction toward the outside. That is, the shape of the refrigerating unit 1 is such that the cabin 3 and the refrigerating unit 1 do not interfere with each other when the vehicle 2 turns. The refrigeration unit 1 according to the present embodiment is a sub-engine type transport refrigeration unit equipped with a dedicated sub-engine 10 as a power source.

As shown in FIGS. 3 and 4, the freezing unit 1 has a housing 6 which is an outer shell of the freezing unit 1. The housing 6 is provided with a partition wall 7 that vertically separates the space inside the housing 6. The upper space separated by the partition wall 7 is a heat exchange room 9 in which the outdoor heat exchanger 8 described later is provided, and the lower space is the engine room 12 in which the main body (engine main body) 11 of the sub engine 10 described later is provided. Become.

As shown in FIGS. 3 to 5, the heat exchange chamber 9 is defined by the upper panel 13 at the front and by the heat insulating wall 14 at the rear. Inside the heat exchange chamber 9, a compressor 15 and an outdoor heat exchanger 8 constituting the refrigerant circuit 50 of the refrigerating unit 1 are housed. The upper panel 13 is formed with two fan openings arranged vertically in the center in the vehicle width direction, and each fan opening has an outdoor heat exchange fan (fan) 16 for introducing outside air into the heat exchange room 9. Arranged one by one. One outdoor heat exchanger 8 is arranged on each of the left and right sides of the outdoor heat exchange fan 16 in the vehicle width direction. Each outdoor heat exchanger 8 is installed so that the inner end in the vehicle width direction is located near the rear surface of the upper panel 13 and the outer end in the vehicle width direction is located near the front surface of the heat insulating wall 14. For convenience of illustration, FIG. 3 shows one of the two outdoor heat exchange fans 16 and omits the other. Further, in FIG. 4, the upper panel 13 is omitted.

In the trailer van body 5 behind the heat exchange room 9 separated from the heat insulating wall 14, a decompression mechanism 17 that constitutes a refrigerant circuit 50 together with a compressor 15 and an outdoor heat exchanger 8 housed in the heat exchange room 9 And the indoor heat exchanger 26 is arranged, and the indoor heat exchange fan 18 is arranged near the upper surface of the trailer van body 5.

As shown in FIGS. 3 and 4, the front of the engine room 12 is defined by the lower panel 19. The lower panel 19 has a removable structure, and is attached / detached during maintenance of parts inside the engine room 12. As described above, the main body 11 of the sub-engine 10 for driving the compressor 15 is housed inside the engine room 12. An opening for a fan is formed in the lower panel 19 substantially in the center in the vehicle width direction, and an engine room ventilation fan 20 for ventilating the engine room 12 is arranged in the fan opening. A generator (not shown) is housed in the engine room 12. The generator converts the rotational energy of the main body 11 of the sub engine 10 into electrical energy. The electric power generated by the generator is supplied to a motor (not shown), and when the electric power is supplied to the motor, the compressor 15 is driven by the driving force of the motor. Although the example in which the compressor 15 is arranged in the heat exchange room 9 has been described above, the compressor 15 may be arranged in the engine room 12. When the compressor 15 is arranged in the engine room 12, it may be arranged as shown by the broken line in FIG. In FIG. 4, the lower panel 19 is omitted.

The sub-engine 10 includes a main body portion 11, an intake pipe 21 having one end connected to the main body portion 11 to supply combustion air to the main body portion 11, and an air cleaner 22 provided in the middle of the intake pipe 21. As described above, the main body 11 is arranged in the engine room 12. As shown in FIG. 6, the intake pipe 21 is provided at the upstream portion 23 extending upward from the main body portion 11, the downstream portion 24 extending substantially in a U shape from the downstream end of the upstream portion 23, and the lower end of the downstream portion 24. It has an air intake port 25 that is formed and opens downward. As shown in FIGS. 3 and 4, the upstream portion 23 extending upward from the main body portion 11 penetrates the partition wall 7 and extends to the heat exchange chamber 9. That is, of the intake pipe 21, a part of the upstream portion 23, the downstream portion 24, and the intake port 25 are located in the heat exchange chamber 9. The intake pipe 21 located in the heat exchange chamber 9 has a J-shaped upside down shape (see FIG. 6) and opens to the partition wall 7 side (engine room 12 side). As shown in FIGS. 3 and 4, an air cleaner 22 is provided in the middle of the upstream portion 23. The air cleaner 22 is provided in the engine room 12, and an element (not shown) provided inside removes foreign substances other than air such as water and dust that have flowed in from the intake port 25. The exhaust generated by driving the main body 11 flows through the inside of the exhaust pipe 27 and is discharged above the refrigerating unit 1 via the muffler 28. Note that, in FIGS. 3 and 4, the detailed shape of the intake pipe (see FIG. 6) is omitted.

Next, the refrigerant circuit 50 will be described with reference to FIG. According to the refrigerant circuit 50 described above, first, the refrigerant compressed by the compressor 15 is sent to the outdoor heat exchanger 8 via the pipe. The refrigerant sent to the outdoor heat exchanger 8 is heat-exchanged with the outside air introduced into the heat exchange chamber 9 by the outdoor heat exchange fan 16 to be cooled and condensed. The condensed refrigerant is sent to the depressurizing mechanism 17 arranged in the trailer van body 5 to be depressurized. The decompressed refrigerant is then sent to the indoor heat exchanger 26. The air in the trailer van body 5 is supplied to the indoor heat exchanger 26 by the indoor heat exchange fan 18. When the air in the trailer van body 5 is supplied to the indoor heat exchanger 26, the refrigerant evaporating in the indoor heat exchanger 26 and the air in the trailer van body 5 exchange heat, and the air in the trailer van body 5 exchanges heat. The air is cooled. After that, the refrigerant that has exchanged heat with the air in the trailer van body 5 is returned to the compressor 15 in the heat exchange chamber 9, and this cycle is repeated in the refrigerant circuit 50 as shown by the arrow 50S in FIG.

Next, the flow of air introduced from the outdoor heat exchange fan 16 into the heat exchange room 9 and the position where the intake pipe 21 in the heat exchange room 9 is arranged will be described with reference to FIG.
As shown by the solid arrow in FIG. 5, the air introduced into the heat exchange chamber 9 from the outdoor heat exchange fan 16 heads rearward and collides with the heat insulating wall 14 defining the rear side in the heat exchange chamber 9. The air that collides with the heat insulating wall 14 is divided into left and right in the vehicle width direction. The left and right separated air flows along the heat insulating wall 14 (each facing from the center of the heat insulating wall 14 in the vehicle width direction to the outside in the vehicle width direction) and passes through the outdoor heat exchanger 8. That is, the outside air introduced into the heat exchange room 9 by the outdoor heat exchange fan 16 flows toward the outdoor heat exchanger 8. Such an air flow becomes the mainstream of the air flow introduced into the heat exchange room 9.

The intake port 25 provided in the intake pipe 21 is opened at a position avoiding this mainstream. Specifically, as shown by the broken line 30R in FIG. 5, it is arranged behind the inner end portion of the outdoor heat exchanger 8 arranged in the heat exchange chamber 9. Further, the intake pipe 21 is provided so that the intake port 25 is located outside and behind the vehicle width direction with respect to the upstream portion 23. That is, the intake port 25 opens in the downstream direction of the main flow of the air flowing in the heat exchange chamber 9, and the outside air is taken in from the intake port 25 as shown by the arrow 25a in FIG.

According to this embodiment, the following effects are exhibited.
In the present embodiment, the intake port 25 of the intake pipe 21 that sends air to the main body 11 of the sub engine 10 is open to the heat exchange chamber 9 (see FIGS. 3 and 4). As a result, the air in the heat exchange chamber 9 can be taken in from the intake port 25 and sent to the main body 11 of the sub engine 10 via the intake pipe 21. Since the heat exchange room 9 is located above the engine room 12 and is far from the traveling engine 31, it is not easily affected by the exhaust heat of the traveling engine 31, and the air in the heat exchange room 9 has pressure and pressure. The temperature is stable. Further, since the heat exchange room 9 is separated from the space where the main body 11 is provided by the partition wall 7, the heat exhausted from the main body 11 whose temperature and pressure change according to the degree of output of the sub engine 10. Not affected by. Therefore, the pressure and temperature of the air in the heat exchange chamber 9 are stable. Further, since the heat exchange room 9 is separated from the space where the main body 11 is provided by the partition wall 7, the pressure fluctuation due to the vibration of the main body 11 does not occur in the heat exchange room 9, and the heat exchange occurs. The pressure of the air in the room 9 is stable. As described above, the pressure and temperature of the air in the heat exchange chamber 9 are stabilized, so that the air having a stable pressure and temperature can be supplied from the intake port 25 to the main body 11 of the sub engine 10 as combustion air. Therefore, it is possible to suppress the vibration of the sub engine 10 due to the intake pressure pulsation caused by the fluctuation of the pressure and temperature of the air supplied to the main body 11. Further, since the vibration of the panels generated due to the vibration of the sub engine 10 can be suppressed, the noise caused by the vibration of the panels can be suppressed.
Further, it is possible to realize a configuration in which the vibration of the sub engine 10 is suppressed without using any parts other than the parts of the existing refrigeration unit 1.
Further, since the housing 6 of the refrigerating unit 1 is divided into two spaces by a partition wall 7 and the main body portion 11 of the sub engine 10 is housed inside the engine room 12 which is one of the spaces, the main body portion 11 is used. The radiated noise can be blocked by the partition wall 7. Therefore, the noise radiated from the freezing unit 1 can be reduced.

Further, the air cleaner 22 is arranged in the engine room 12 located below the heat exchange room 9 (see the figure). Therefore, even when the refrigerating unit 1 is located high above the ground as in the present embodiment, the air cleaner 22 can be easily inspected and the elements of the air cleaner 22 can be easily replaced. Therefore, the maintainability of the air cleaner 22 can be improved. Further, the sub-engine 10 generally has many parts that need to be replaced and inspected, and in order to replace and inspect such parts, the lower panel 19 that defines the front of the engine room 12 becomes removable. There is. In the present embodiment, since the air cleaner 22 is arranged in the engine room 12 in which the parts that need to be replaced and inspected are housed, the detachable lower panel 19 can be removed and the element of the air cleaner 22 can be easily replaced. Can be done.

Further, the outdoor heat exchange fan 16 introduces the outside air into the heat exchange room 9. Therefore, air having a relatively low temperature similar to that of the outside air can be supplied from the intake port 25 to the main body 11 of the sub engine 10. Therefore, it is possible to prevent a decrease in the output of the sub engine 10 due to an increase in the intake air temperature.
Further, since the outside air is introduced into the heat exchange room 9 by the outdoor heat exchange fan 16, the pressure in the heat exchange room 9 is kept constant. Therefore, it is possible to supply air with a stable pressure to the main body 11.
Further, in the present embodiment, the outdoor heat exchange fan 16 of the refrigerating unit 1 is arranged above the cabin 3. Therefore, since the outside air can be introduced into the heat exchange room 9 without being blocked by the cabin 3, it is possible to easily introduce the outside air into the heat exchange room 9. Further, it is possible to easily introduce air that is not affected by the vehicle 2 (for example, the influence of exhaust heat of the traveling engine 31).

The outdoor heat exchange fan 16 is provided on the front side of the housing 6. Therefore, when introducing the outside air (for example, the vehicle traveling wind) from the front to the rear of the vehicle 2 into the heat exchange room 9, the ram pressure can be used, and the outside air is preferably introduced into the heat exchange room 9. can do.

Further, the intake port 25 is opened from the outdoor heat exchange fan 16 at a position avoiding the mainstream of the outside air introduced into the heat exchange room 9 (see FIG. 5). Therefore, it is difficult for rainwater, dust, etc. contained in the outside air introduced into the heat exchange room 9 to be directly introduced into the intake pipe 21 from the intake port 25. Therefore, it is possible to prevent foreign matter other than air from being introduced into the main body 11 of the sub engine 10 via the intake pipe 21.

Further, rainwater and dust contained in the outside air introduced from the outdoor heat exchange fan 16 into the heat exchange room 9 are directed downward from above due to gravity. In the present embodiment, since the outside air is introduced in the direction of the arrow in FIG. 6 from the intake port 25 opened downward, rainwater, dust, etc. contained in the outside air introduced in the heat exchange room 9 can be directly introduced. It is difficult to introduce it from the intake port 25 to the intake pipe 21. Further, even when rainwater or dust flows into the heat exchange room 9 from other than the outdoor heat exchange fan 16, it is difficult for rainwater or dust to be directly introduced from the intake port 25 which is open downward. Therefore, it is possible to prevent foreign matter other than air from being introduced into the main body 11 of the sub engine 10 via the intake pipe 21.

Further, the intake port 25 opens from the outdoor heat exchange fan 16 in the downstream direction of the mainstream of the outside air introduced into the heat exchange room 9 (see FIG. 5). Therefore, since the introduced outside air is not directly introduced into the intake port 25, it is difficult for rainwater, dust, etc. contained in the outside air introduced in the heat exchange room 9 to be directly introduced into the intake pipe 21 from the intake port 25. .. Therefore, it is possible to prevent foreign matter other than air from being introduced into the main body 11 of the sub engine 10 via the intake pipe 21.

The present invention is not limited to the invention according to the above embodiment, and can be appropriately modified without departing from the gist thereof. For example, in the present embodiment, the motor is driven by the electric power generated by the driving force of the sub engine 10, and the compressor 15 is driven by the driving force of the motor. However, the sub engine does not go through the generator and the motor. The compressor 15 may be directly driven by the driving force of 10.

Further, in the present embodiment, the intake pipe 21 is arranged behind the inner end portion of the outdoor heat exchanger 8 (the oval 30R of the broken line in FIG. 5), but the arrangement of the intake pipe 21 is not limited to this. The intake pipe 21 may be arranged in the oval 30L of the broken line in FIG. Further, the intake pipe 21 may be arranged at another position as long as it avoids the main flow of the air flow introduced into the heat exchange chamber 9.

1 Refrigeration unit (sub-engine type transportation refrigeration unit)
5 Trailer van body 6 Housing 7 Partition 8 Outdoor heat exchanger 9 Heat exchange room 10 Sub engine 11 Main body (engine main body)
12 Engine room 16 Outdoor heat exchange fan (fan)
21 Intake pipe 22 Air cleaner 25 Intake port

Claims (6)

An engine body and a sub-engine that is connected to the engine body and has an intake pipe that supplies air to the engine body to drive a compressor.
A housing for accommodating the sub-engine and
The housing is provided with a partition wall that vertically separates the engine room in which the engine body is installed and another space in which the engine body is not installed.
A fan provided in the housing and for introducing outside air into the other space is provided.
The intake pipe has an intake port that opens to the other space side and penetrates the partition wall .
The intake port is opened at a position avoiding the mainstream of the outside air introduced into the other space from the fan.
The intake port is a sub-engine type transportation refrigeration unit that opens in the downstream direction of the mainstream. The engine room is located below the other space and
The intake pipe is equipped with an air cleaner.
The sub-engine type transport refrigeration unit according to claim 1, wherein the air cleaner is arranged in the engine room. The sub-engine type transport refrigerating unit according to claim 1 or 2, wherein the fan is provided on the front side of the vehicle in the housing when installed in a vehicle. The sub-engine type transport refrigeration unit according to any one of claims 1 to 3, wherein the intake port is open downward. A vehicle provided with the sub-engine type transport refrigeration unit according to any one of claims 1 to 4. An engine body and a sub-engine that is connected to the engine body and has an intake pipe that supplies air to the engine body to drive a compressor.
A housing for accommodating the sub-engine and
The housing is provided with a partition wall that vertically separates the engine room in which the engine body is installed and another space in which the engine body is not installed.
A fan provided in the housing and for introducing outside air into the other space is provided.
The intake pipe has an intake port that opens to the other space side.
The intake port is opened at a position avoiding the mainstream of the outside air introduced into the other space from the fan.
The intake port is a sub-engine type transportation refrigeration unit that opens in the downstream direction of the mainstream.

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