Refrigerated vehicle system and brake negative pressure control device for refrigerated vehicle

Abstract

To provide a refrigeration vehicle and a brake negative pressure control device of the same which can suppress deterioration of brake negative pressure in a brake booster and recover the negative pressure in the brake booster.SOLUTION: A refrigeration vehicle system 10 comprises: a vacuum type brake booster 43 which uses engine negative pressure to decrease brake operation force; a refrigerator 20 which is arranged in a cargo chamber 14A of a vehicle 12; and a controller 30 which stops the refrigerator 20 when the brake negative pressure in the brake booster 43 is a prescribed threshold value or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a refrigerated vehicle system and a brake negative pressure control device for a refrigerated vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle equipped with a brake booster that supplies negative pressure to the engine intake passage to assist the driver in braking. On the other hand, a refrigerated vehicle is also known in which a refrigerator is mounted on a vehicle equipped with a brake booster. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-110505 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described refrigerated vehicle, when the refrigerator is operated, the load of the refrigerator drive compressor is applied to the engine, which may reduce the amount of engine negative pressure. When the amount of engine negative pressure is reduced, the amount of negative pressure supplied from the engine to the brake booster decreases, which may increase the force required for the driver to apply the brakes compared to when the refrigerator is not operating.

[0005] In consideration of the above, the present invention aims to provide a refrigerated vehicle and a brake negative pressure control device for a refrigerated vehicle that can suppress a decrease in brake negative pressure in a brake booster and restore brake negative pressure in the brake booster. [Means for solving the problem]

[0006] The refrigerated vehicle system according to the present invention as set forth in claim 1 comprises a vacuum brake booster that reduces brake operation force by utilizing engine negative pressure, a refrigerator provided in a luggage compartment of the vehicle, and a control unit that stops the refrigerator when the brake negative pressure in the brake booster is equal to or less than a predetermined threshold. The refrigerator includes a freezing valve that is opened during a freezing operation and a defrosting valve that is opened during a defrosting operation, and the control unit stops the refrigerator and opens the freezing valve and the defrosting valve when the brake negative pressure is equal to or less than the predetermined threshold. .

[0007] In the refrigerated vehicle system according to the present invention, the control unit stops the refrigerator installed in the luggage compartment of the vehicle when the brake negative pressure in a vacuum brake booster, which reduces brake application force by utilizing engine negative pressure, is below a predetermined threshold. Therefore, stopping the refrigerator reduces the load on the engine caused by the refrigerator drive compressor, thereby preventing a decrease in the amount of engine negative pressure generated. This prevents a decrease in the amount of negative pressure supplied from the engine to the brake booster, thereby preventing a decrease in brake negative pressure in the brake booster. Furthermore, stopping the refrigerator reduces the load on the engine, allowing engine negative pressure to recover.

[0009] When the brake negative pressure is equal to or lower than a predetermined threshold, if the refrigerator is repeatedly stopped and restarted in a short period of time, the compressor will operate with a high refrigerant pressure difference between the outlet and inlet of the compressor in the refrigeration cycle, which may place a high load on the compressor and reduce its durability. 1 In the refrigeration vehicle system according to the present invention described above, when the brake negative pressure is equal to or less than a predetermined threshold, the control unit stops the refrigerator and opens the freezing valve that is open during freezing operation and the defrosting valve that is open during defrosting operation. This makes it possible to equalize the refrigerant pressure difference between the outlet and inlet of the compressor in the refrigeration cycle, thereby reducing the load on the compressor.

[0010] The refrigeration vehicle system of the present invention described in claim 2 includes a vacuum brake booster that reduces brake operation force by utilizing engine negative pressure, a refrigerator provided in the luggage compartment of the vehicle, a control unit that stops the refrigerator when the brake negative pressure in the brake booster is equal to or lower than a predetermined threshold, and a vacuum tank that accumulates gas at a negative pressure lower than atmospheric pressure, and the control unit activates the brake booster by utilizing the negative pressure in the vacuum tank when the brake negative pressure is equal to or lower than the predetermined threshold. In the refrigerated vehicle system according to the present invention, the control unit stops the refrigerator installed in the luggage compartment of the vehicle when the brake negative pressure in a vacuum-type brake booster, which reduces brake application force by utilizing engine negative pressure, is equal to or lower than a predetermined threshold. Therefore, stopping the refrigerator reduces the load on the engine caused by the refrigerator drive compressor, thereby preventing a decrease in the amount of engine negative pressure generated. This prevents a decrease in the amount of negative pressure supplied from the engine to the brake booster, thereby preventing a decrease in brake negative pressure in the brake booster. Furthermore, stopping the refrigerator reduces the load on the engine, allowing the engine negative pressure to recover. The refrigeration vehicle system according to the present invention as set forth in claim 3 is 1 toIn the described configuration, a vacuum tank is provided that accumulates gas at a negative pressure lower than atmospheric pressure, and the control unit activates the brake booster using the negative pressure in the vacuum tank when the brake negative pressure is equal to or lower than the predetermined threshold.

[0011] Claim 2 and In the refrigerated vehicle system according to the present invention, the control unit activates the brake booster by utilizing the negative pressure in the vacuum tank when the brake negative pressure is equal to or lower than a predetermined threshold. This prevents the brake negative pressure from decreasing even after multiple braking operations. This ensures a sufficient brake negative pressure compared to when there is no vacuum tank, preventing an increase in the operating force required for braking, which is unique to refrigerated vehicles.

[0012] The refrigeration vehicle system of the present invention described in claim 4, in the configuration described in any one of claims 1 to 3, is provided with an alarm unit that notifies the driver that more brake operating force is required than usual when the brake negative pressure is below the predetermined threshold.

[0013] In the refrigeration vehicle system of the present invention described in claim 4, the notification unit notifies the driver that more brake application force is required than usual when the brake negative pressure is below a predetermined threshold, so that the driver can recognize that more brake application force is required than usual, i.e., that there is insufficient brake negative pressure.

[0014] The refrigeration vehicle system of the present invention described in claim 5 has the configuration described in claim 4, wherein the notification unit issues a notification when the brake negative pressure remains below the specified threshold for a predetermined period of time when the brake is applied.

[0015] In the refrigeration vehicle system according to the present invention as set forth in claim 5, the notification unit issues a notification when the brake negative pressure remains below a predetermined threshold for a predetermined period of time when the brakes are applied, thereby preventing unnecessary notifications to the driver when the brake negative pressure drops due to reasons other than braking, or when the brake negative pressure drops for a short period of time during braking but has little effect on the brake application force.

[0016] The refrigeration vehicle system of the present invention described in claim 6 is configured as described in any one of claims 1 to 5, and the control unit stops the refrigeration machine when the brake negative pressure is below a predetermined threshold when the brake is applied.

[0017] In the refrigerated vehicle system according to the present invention as set forth in claim 6, the control unit stops the refrigerator when the brake negative pressure is equal to or less than a predetermined threshold when the brake is applied, so that the refrigerator is not stopped when the brake is not applied, thereby shortening the time the refrigerator is stopped, thereby suppressing a rise in temperature of the refrigerator.

[0018] The refrigeration vehicle system of the present invention described in claim 7 is configured as described in any one of claims 1 to 6, and the control unit restarts the refrigerator after a predetermined time has elapsed when the brake negative pressure is greater than a predetermined threshold value.

[0019] In the refrigeration vehicle system according to the present invention as set forth in claim 7, the control unit restarts the refrigerator after a predetermined time has elapsed when the brake negative pressure is greater than a predetermined threshold. This ensures time for the brake negative pressure to recover and also ensures time required for the refrigerant pressure at the outlet and inlet of the compressor in the refrigeration cycle to become equal, thereby reducing the load on the compressor when it is restarted.

[0020] The refrigeration vehicle system of the present invention described in claim 8 is configured as described in any one of claims 1 to 7, wherein the control unit stops the refrigerator when the brake negative pressure is below a predetermined threshold when the brake is applied, and restarts the refrigerator when the brake is released.

[0021] In the refrigerated vehicle system according to the present invention as set forth in claim 8, the control unit stops the refrigerator when the brake negative pressure is equal to or less than a predetermined threshold when the brake is applied, and restarts the refrigerator when the brake is released. Therefore, when the brake is released, no brake operation force is required, so by restarting the refrigerator, the stop time of the refrigerator can be shortened, thereby maintaining the cooling performance of the refrigerator.

[0022] The brake negative pressure control device for a refrigerated vehicle according to the present invention is provided with a brake booster that utilizes engine negative pressure to assist the brake operation force, and is provided in the luggage compartment. The freezing valve is opened during freezing operation, and the defrosting valve is opened during defrosting operation. In a refrigerated vehicle equipped with a refrigerator, when the brake negative pressure in the brake booster is equal to or lower than a predetermined threshold, the refrigerator is stopped. and the freezing valve and the defrosting valve are in an open state. do.

[0023] According to the brake negative pressure control device for a refrigerated vehicle of the present invention as set forth in claim 9, when the brake negative pressure in a vacuum-type brake booster that reduces brake operation force by utilizing engine negative pressure is equal to or lower than a predetermined threshold, the refrigerator installed in the luggage compartment of the vehicle is stopped. Therefore, by stopping the refrigerator, the load on the refrigerator drive compressor that was applied to the engine can be reduced, thereby preventing a decrease in the amount of engine negative pressure generated. This prevents a decrease in the amount of negative pressure supplied from the engine to the brake booster, thereby suppressing a decrease in brake negative pressure in the brake booster. Furthermore, by stopping the refrigerator, the load on the engine is reduced, allowing the engine negative pressure to be restored. The brake negative pressure control device for a refrigerated vehicle according to the present invention as set forth in claim 10 comprises: A brake booster that uses engine vacuum to assist braking force a vacuum tank that accumulates gas at a negative pressure lower than atmospheric pressure;In a refrigerated vehicle equipped with the above-mentioned brake booster and having a refrigerator in a luggage compartment, when a brake negative pressure in the brake booster is equal to or lower than a predetermined threshold, the refrigerator is stopped. The negative pressure in the vacuum tank is used to operate the brake booster. do. [Effects of the Invention]

[0024] As described above, the refrigerated vehicle and the brake negative pressure control device for the refrigerated vehicle according to the present invention have the excellent effect of suppressing a decrease in the brake negative pressure in the brake booster and restoring the brake negative pressure in the brake booster. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic side view showing a configuration of a refrigerated vehicle system according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram schematically showing a control configuration including a control unit according to a first embodiment of the present invention. [Figure 3] FIG. 2 is a systematic explanatory diagram showing an example of a refrigeration cycle of the refrigerated vehicle system of FIG. [Figure 4] 10 is a graph showing the relationship between brake operation time and brake negative pressure. [Figure 5] 5 is a flowchart showing an example of control processing of a control unit according to the first embodiment of the present invention. [Figure 6] 5A and 5B are diagrams illustrating an example of control processing of a control unit during a freezing operation and a defrosting operation of a refrigerator. [Figure 7] FIG. 4 is a diagram illustrating an example of timing of control processing by a control unit. [Figure 8] FIG. 10 is a diagram showing an example of timing of control processing of a control unit according to a modified example of the first embodiment of the present invention. [Figure 9] 10 is a flowchart showing an example of control processing of a control unit according to a modified example of the first embodiment of the present invention. [Figure 10] FIG. 10 is a block diagram schematically showing a control configuration including a control unit according to a second embodiment of the present invention. [Figure 11]4 is a graph showing the relationship between brake operation force and brake negative pressure. DETAILED DESCRIPTION OF THE INVENTION

[0026] A refrigerated vehicle system 10 according to one embodiment of the present invention will be described below with reference to Figures 1 to 7. Figure 1 is a schematic side view showing a configuration of a refrigerated vehicle system 10 according to a first embodiment of the present invention.

[0027] As shown in Figure 1, the refrigerated vehicle system 10 includes a refrigerated vehicle body 12 and a container 14 connected to the vehicle-facing side of the refrigerated vehicle body 12. The interior of the container 14 is a luggage compartment 14A, and a refrigeration unit 20 is provided in the luggage compartment 14A. The refrigeration unit 20 includes a freezer compartment formed by the luggage compartment 14A, and the luggage compartment 14A (freezer compartment) is capable of being sealed.

[0028] The refrigeration vehicle body 12 is equipped with a control unit 30 as a control device that controls the travel of the refrigeration vehicle body 12 and the entire refrigeration vehicle system 10, such as the refrigeration unit 20, a brake device 40, an engine 16, and an alarm unit 18 (see FIG. 2). The engine 16 is a power source that drives the refrigeration vehicle body 12. In this embodiment, the engine 16 is also connected to the compressor 50 of the refrigeration unit 20 by a compressor clutch 52 (see FIG. 2), and the engine 16 also drives the compressor 50 of the refrigeration unit 20. The compressor clutch 52 has a function of connecting and disconnecting the engine 16 and the compressor 50, and the compressor clutch 52 is controlled by the control unit 30.

[0029] Fig. 2 is a block diagram that schematically shows a control configuration including the control unit 30. As shown in Fig. 2, the braking device 40 includes a brake pedal 42, a brake booster 43, a master cylinder 44, and a brake 46. The brake pedal 42 is a pedal that is depressed by the driver when braking, and is connected to the brake 46 via the master cylinder 44 that is provided integrally with the brake booster 43. The brake 46 includes a brake drive unit 47 that serves as a brake actuator, and a wheel cylinder 48, and the wheel cylinder 48 is connected to the brake drive unit 47. Although not shown, the brake drive unit 47 includes an electromagnetic valve, a motor-driven pump, and the like.

[0030] The brake booster 43 is a vacuum type device that reduces the braking force exerted by the driver by amplifying the force exerted when the brake pedal 42 is depressed. The brake booster 43 is equipped with a negative pressure generating pipe (not shown) for taking in engine negative pressure from the engine 16 of the refrigerated vehicle body 12, and this negative pressure generating pipe is connected to the intake system of the engine 16, thereby supplying engine negative pressure from the engine 16.

[0031] The brake booster 43 takes in the engine negative pressure generated during the intake stroke of the engine 16 through a negative pressure generating pipe, and when the driver depresses the brake pedal 42, the depression force is transmitted to the brake booster 43. This transmitted depression force is multiplied by the engine negative pressure taken into the brake booster 43, and brake fluid pressure is generated in the master cylinder 44. The brake fluid pressure is transmitted to the wheel cylinders 48 via the brake drive unit 47, and the brakes 46 are operated by a brake operation force corresponding to the brake fluid pressure.

[0032] The brake booster 43 is also provided with a negative pressure detection unit 45 that detects the brake negative pressure inside the brake booster. In this embodiment, the negative pressure detection unit 45 is configured as a pressure sensor, for example, and the brake negative pressure detected by the negative pressure detection unit 45 is output to the control unit 30. When the brake negative pressure becomes equal to or less than a predetermined threshold, the negative pressure detection unit 45 outputs an ON brake negative pressure signal to the control unit 30.

[0033] The control unit 30 is also connected to a notification unit 18. When the brake negative pressure detected by the negative pressure detection unit 45 is equal to or lower than a predetermined threshold, the notification unit 18 notifies the driver that more brake operation force is required than usual. The predetermined threshold is set in advance depending on the type of refrigerator 20, the size of the refrigerated vehicle body 12, etc. Specifically, the notification unit 18 is, as an example, configured with a warning lamp, and when the warning lamp is lit, the notification unit 18 notifies the driver that more brake operation force is required than usual. The notification unit 18 is not limited to a warning lamp, and may be configured with, for example, a telltale, a display screen, a speaker, etc.

[0034] 1, the refrigerator 20 includes a compressor 50, a condensing unit 22, a cooling unit 23, and a sight glass 24. The cooling unit 23 and the sight glass 24 are provided in the luggage compartment 14A. FIG. 3 is a systematic explanatory diagram showing an example of the refrigeration cycle of the refrigerated vehicle system 10.

[0035] As shown in Fig. 3, the refrigeration vehicle system 10 comprises a refrigeration cycle including a compressor 50, a condensing unit 22, a cooling unit 23, a sight glass 24, an accumulator 25, and various pipes. In Fig. 3, the open arrows indicate the flow of refrigerant, and the black arrows indicate the flow of compressor oil.

[0036] The compressor 50 compresses the refrigerant flowing in from the first pipe 20A by the driving force transmitted via a compressor clutch 52 (see FIG. 2) from the engine 16 that drives the refrigerated vehicle body 12, thereby increasing the temperature and pressure of the refrigerant and discharging it into the second pipe 20B. The refrigerant contains lubricating oil for lubricating the compression mechanism of the compressor 50.

[0037] In this embodiment, the first pipe 20A functions as an inlet of the compressor 50, and the second pipe 20B functions as an outlet of the compressor 50. That is, the refrigerant flowing through the first pipe 20A is a low-pressure refrigerant before being compressed by the compressor 50, and the refrigerant flowing through the second pipe 20B is a high-pressure refrigerant after being compressed by the compressor 50.

[0038] As an example, the condensing unit 22 has a case (not shown) that is fixed to the chassis of the refrigeration vehicle body 12, and the case contains an oil separator 22A, a condenser 22B, a condenser fan motor 22C, a receiver 22D, a pressure switch 22E, a refrigeration valve 60, and a defrost valve 70.

[0039] The oil separator 22A separates the lubricating oil from the high-pressure refrigerant discharged from the compressor 50 and returns the oil to the compressor 50, thereby preventing the compressor 50 from seizing. The oil separator 22A sends the lubricating oil through a capillary tube and an oil pipe 20C. Here, the oil pipe 20C is a pipe that connects the first pipe 20A and the second pipe 20B.

[0040] Condenser 22B cools the high-temperature, high-pressure refrigerant gas discharged from compressor 50 and condenses and liquefies it by exchanging heat with outside air. Condenser fan motor 22C is a fan for circulating outside air to condenser 22B and is installed next to condenser 22B.

[0041] The receiver 22D separates the refrigerant that has passed through the condenser 22B into a gas phase refrigerant and a liquid phase refrigerant, and guides the liquid phase refrigerant to the cooling unit 23 side.

[0042] The freezing valve 60 includes a valve element (not shown) that opens and closes the flow path between the refrigerant outlet of the receiver 22D and the refrigerant inlet of an expansion valve 23A (described later), and an actuator (not shown) that drives the valve element. A pressure switch 22E is also provided in the piping located between the receiver 22D and the freezing valve 60. This pressure switch 22E maintains the pressure in the refrigeration cycle within a set range and stops the system when an abnormality occurs in the pressure in the refrigeration cycle.

[0043] The sight glass 24 is disposed at the refrigerant inlet of the expansion valve 23A in the luggage compartment 14A, and is a device that allows the flow of the refrigerant inside the piping and changes in the flow rate to be visually confirmed.

[0044] The defrost valve 70 includes a valve body (not shown) that opens and closes the defrost pipe 20D, and an actuator (not shown) that drives the valve body. The defrost pipe 20D is a pipe that connects the refrigerant outlet of the oil separator 22A and the refrigerant inlet of the evaporator 23B, which will be described later.

[0045] The cooling unit 23 has, for example, a case (not shown) fixed in the luggage compartment 14A, and includes an expansion valve 23A, an evaporator 23B, and a cooling fan motor 23C inside the case.

[0046] The expansion valve 23A is a pressure reducing valve that is provided in a pipe between the refrigerant outlet of the receiver 22D and the refrigerant inlet of the evaporator 23B and adjusts the opening of the refrigerant flow path in this pipe. The expansion valve 23A reduces the pressure of the liquid-phase refrigerant discharged from the receiver 22D.

[0047] The evaporator 23B evaporates the low-pressure refrigerant that has passed through the expansion valve 23A and exchanges heat with the air in the luggage compartment 14A, thereby removing heat from the air in the luggage compartment 14A and cooling the air in the luggage compartment 14A. The cooling fan motor 23C is a fan for circulating outside air through the evaporator 23B and is provided adjacent to the evaporator 23B.

[0048] The accumulator 25 separates the low-pressure refrigerant that has passed through the evaporator 23B into a gas-phase refrigerant and a liquid-phase refrigerant, stores the liquid-phase refrigerant, and discharges the gas-phase refrigerant to the first pipe 20A.

[0049] In this embodiment, the valve elements of the freeze valve 60 and the defrost valve 70 are opened and closed via respective actuators in response to commands from the control unit 30 .

[0050] Next, a control method for the refrigerated vehicle body 12 and the refrigerator 20 by the control unit 30 of the refrigerated vehicle system 10 of this embodiment will be described. In this embodiment, the control unit 30 functions as a brake negative pressure control device for the refrigerated vehicle in addition to a control device that controls the travel of the refrigerated vehicle body 12. As described above, the refrigerated vehicle system 10 of this embodiment includes the refrigerator 20 that is operated by the driving force of the engine 16 that drives the refrigerated vehicle body 12, and the brake booster 43 that uses the engine negative pressure of the engine 16.

[0051] Therefore, when the refrigerator 20 is operated, the load of the compressor 50 of the refrigerator 20 is applied to the engine 16, which may reduce the amount of engine vacuum generated. If the amount of engine vacuum generated decreases, the amount of engine vacuum supplied from the engine 16 to the brake booster 43 decreases, which may increase the operating force required for the driver to apply the brakes compared to when the refrigerator 20 is not operating. Figure 4 is a graph showing the relationship between brake operation time and brake vacuum. In Figure 4, the horizontal axis represents the operation time of the brake 46, and the vertical axis represents brake vacuum.

[0052] Therefore, in this embodiment, as shown in Fig. 4, when the brake 46 is depressed and the brake negative pressure detected by the negative pressure detection unit 45 is equal to or less than a predetermined threshold, the control unit 30 stops the refrigerator 20. Specifically, the control unit 30 turns off the compressor clutch 52 to disconnect the compressor 50 of the refrigerator 20 from the engine 16. In this embodiment, whether or not the brake is being applied is detected based on, for example, a signal output from a hydraulic sensor (not shown) that detects the hydraulic pressure of the master cylinder 44. Note that the detection of whether or not the brake is being applied is not limited to the hydraulic sensor, and for example, an operation signal of an antilock brake system (ABC) or an existing signal may be used.

[0053] Fig. 5 is a flowchart showing an example of the control process of the control unit 30, Fig. 6 is a diagram showing an example of the control process of the control unit 30 during freezing operation and defrosting operation of the refrigerator 20, and Fig. 7 is a diagram showing an example of the timing of the control process of the control unit 30. Note that (A) on the left side of Fig. 6 shows the control by the control unit 30 during freezing operation of the refrigerator 20, and (B) on the right side of Fig. 6 shows the control by the control unit 30 during defrosting operation of the refrigerator 20. Also, in Fig. 7, for convenience, the freezing valve 60 shows the operating state during defrosting operation, and the defrost valve 70 shows the operating state during freezing operation, and the same control process as in Fig. 6 is performed.

[0054] 5, in step S11, the control unit 30 determines whether or not a brake operation has started. If a brake operation has started (step S11; YES), in step S12, the control unit 30 determines whether or not the brake negative pressure is equal to or less than a predetermined threshold. If the brake negative pressure is equal to or less than the predetermined threshold (step S12; YES), in step S13, the control unit 30 stops the refrigerator 20 because the brake operation force required for the brake operation will increase.

[0055] That is, as shown in Fig. 7, when the brake operation signal is changed from an OFF state to an ON state and the brake negative pressure signal is changed to an ON state, the control unit 30 starts controlling the refrigeration cycle shown in Fig. 3. Specifically, the control unit 30 stops the refrigerator 20 by changing the compressor clutch 52 from an ON state (connected state) to an OFF state (disconnected state). On the other hand, if the refrigerator 20 is repeatedly stopped and started, an excessive load is placed on the compressor 50. Therefore, in this embodiment, the control unit 30 controls the opening and closing of each valve element of the freeze valve 60 and the defrost valve 70 shown in Fig. 3.

[0056] As shown in the left diagram (A) of Figure 6, when the refrigerator 20 is in freezing operation, the control unit 30 changes the compressor clutch 52 from the on state (connected state) to the off state (open state) when the brake negative pressure signal changes from the off state to the on state. Since the freezer valve 60 is in the on state when the refrigerator 20 is in freezing operation, the control unit 30 causes the freezer valve 60 to continue in the on state. Furthermore, since the defrost valve 70 is in the off state when the refrigerator 20 is in freezing operation, the control unit 30 changes the defrost valve 70 from the off state to the on state. Here, the open state of the valve body of each of the freezer valve 60 and the defrost valve 70 is the on state, and the closed state of each of the valve bodies is the off state.

[0057] 6(B), when the refrigerator 20 is in defrosting operation, the control unit 30 changes the compressor clutch 52 from the on state (connected state) to the off state (open state) when the brake negative pressure signal changes from the off state to the on state. Since the freezer valve 60 is in the off state when the refrigerator 20 is in defrosting operation, the control unit 30 changes the freezer valve 60 from the off state to the on state. Furthermore, since the defrost valve 70 is in the on state when the refrigerator 20 is in defrosting operation, the control unit 30 keeps the defrost valve 70 in the on state.

[0058] That is, when the brake negative pressure signal changes from an off state to an on state, the control unit 30 changes the compressor clutch 52 from an on state (connected state) to an off state (open state), and also changes each valve element of the freeze valve 60 and the defrost valve 70 to an on state.

[0059] On the other hand, returning to FIG. 5, if the brake operation has not started in step S11 (step S11; NO), or if the brake negative pressure is greater than a predetermined threshold value in step S12 (step S12; NO), the control unit 30 proceeds to step S18, and in step S18, the control unit 30 does not stop the refrigerator 20 because it determines that there is no effect on the brake operation force.

[0060] On the other hand, after the control unit 30 stops the refrigerator 20 in step S13, the control unit 30 determines whether or not the brake operation is continuing in step S14. If the brake operation is continuing (step S14; YES), the control unit 30 continues stopping the refrigerator 20 in step S15 and proceeds to step S14.

[0061] That is, as shown in FIGS. 6 and 7, the control unit 30 keeps the compressor clutch 52 in the OFF state (open state), and keeps the freeze valve 60 and the defrost valve 70 in the ON state.

[0062] Furthermore, in step S14, if the brake operation is not being continued (step S14; NO), the control unit 30 restarts the refrigerator 20 in step S16.

[0063] 6A, during the freezing operation of the refrigerator 20, the control unit 30 changes the compressor clutch 52 from the OFF state (disengaged state) to the ON state (engaged state) when the brake operation signal changes from the ON state to the OFF state. Here, as an example in this embodiment, if the brake operation signal changes to the OFF state while the compressor clutch 52 is in the OFF state (disengaged state), the control unit 30 changes the compressor clutch 52 to the ON state (engaged state) after a time T1 has elapsed since the brake operation signal changed to the OFF state.

[0064] Furthermore, since the freezing valve 60 is in the ON state when the refrigerator 20 is stopped, the control unit 30 keeps the freezing valve 60 in the ON state. Furthermore, since the defrosting valve 70 is in the ON state when the refrigerator 20 is stopped, the control unit 30 changes the defrosting valve 70 from the ON state to the OFF state. Here, as an example in this embodiment, the control unit 30 changes the defrosting valve 70 to the OFF state after a time T2 has elapsed since the compressor clutch 52 was turned OFF (opened state).

[0065] Also, as shown in the right diagram (B) of Figure 6, during defrosting operation of the refrigerator 20, if the brake operation signal is turned off while the compressor clutch 52 is in the off state (disengaged state), the control unit 30 changes the compressor clutch 52 from the off state (disengaged state) to the on state (engaged state) after the elapse of time T1 from when the brake operation signal is turned off, just like during refrigeration operation.

[0066] Furthermore, since the freeze valve 60 is in the ON state when the refrigerator 20 is stopped, the control unit 30 changes the freeze valve 60 from the ON state to the OFF state when the compressor clutch 52 is turned ON. Furthermore, since the defrost valve 70 is in the ON state when the refrigerator 20 is stopped, the control unit 30 keeps the defrost valve 70 in the ON state.

[0067] Returning to Fig. 5, after the refrigerator 20 is restarted in step S16, the control unit 30 determines in step S17 whether the brake negative pressure has recovered. Specifically, the control unit 30 determines whether the brake negative pressure signal has turned off. If the brake negative pressure has recovered (step S17; YES), the control unit 30 determines in step S18 that there is no effect on the brake operating force and does not stop the refrigerator 20.

[0068] On the other hand, if the brake negative pressure has not recovered in step S17 (step S17; NO), in step S19, the control unit 30 causes the notification unit 18 to warn the driver that more brake operation force is required than usual. As shown in Fig. 7, the notification unit 18 issues the warning when the brake negative pressure is equal to or less than a predetermined threshold for a predetermined time T3 after the brake operation. Specifically, the control unit 30 turns on the warning lamp of the notification unit 18 when the time T3 measured by a timer (not shown) has elapsed since the brake operation signal was changed from an OFF state to an ON state and the brake negative pressure signal was changed to an ON state.

[0069] Next, in step S20, the control unit 30 determines whether the refrigerated vehicle body 12 has stopped. For example, the control unit 30 determines that the refrigerated vehicle body 12 has stopped when the shift range of the refrigerated vehicle body 12 is shifted to parking, or when the engine 16 of the refrigerated vehicle body 12 is stopped. If the refrigerated vehicle body 12 has stopped in step S20 (step S20; YES), the control unit 30 ends all processing. On the other hand, if the refrigerated vehicle body 12 has not stopped in step S20 (step S20; NO), the control unit 30 proceeds to step S11 and continues processing from step S11 onwards.

[0070] In this embodiment, as shown in FIG. 7, the control unit 30 controls the refrigeration cycle of the refrigerator 20 during a time T4 from when the brake negative pressure signal is turned on until the defrost valve 70 is turned off.

[0071] Next, the operation and effects of the first embodiment will be described.

[0072] In the refrigerated vehicle system 10 according to the first embodiment, the control unit 30 stops the refrigerator 20 provided in the luggage compartment 14A of the vehicle when the brake negative pressure in the vacuum brake booster 43, which reduces the brake operation force by utilizing engine negative pressure, is equal to or lower than a predetermined threshold. Therefore, stopping the refrigerator 20 reduces the load on the compressor 50 that drives the refrigerator 20 and that was applied to the engine 16, thereby preventing a decrease in the amount of engine negative pressure generated. This prevents a decrease in the amount of negative pressure supplied from the engine 16 to the brake booster 43, thereby preventing a decrease in the brake negative pressure in the brake booster 43. Furthermore, stopping the refrigerator 20 reduces the load on the engine 16, allowing the engine negative pressure to recover.

[0073] On the other hand, if the brake negative pressure is below a predetermined threshold, repeatedly stopping and restarting the refrigerator 20 in a short period of time will cause the compressor 50 to operate with a high refrigerant pressure difference between the outlet (second piping 20B) and inlet (first piping 20A) of the compressor 50 in the refrigeration cycle, which may place a high load on the compressor 50 and reduce its durability.

[0074] In the refrigeration vehicle system 10 according to the first embodiment, when the brake negative pressure is equal to or lower than a predetermined threshold, the control unit 30 stops the refrigerator 20 and opens (turns on) the freeze valve 60, which is open (on) during freezing operation, and the defrost valve 70, which is open (on) during defrosting operation. By opening (turning on) the defrost valve 70 when the refrigerator 20 is stopped, the refrigerant pressure difference between the outlet (second pipe 20B) and inlet (first pipe 20A) of the compressor 50 in the refrigeration cycle can be equalized. Furthermore, by opening (turning on) the freeze valve 60 when the refrigerator 20 is stopped, the refrigerant pressure at the outlet (second pipe 20B) of the compressor 50 in the refrigeration cycle can be continuously released. In this way, the load on the compressor 50 can be reduced by equalizing the refrigerant pressure difference between the outlet (second piping 20B) and inlet (first piping 20A) of the compressor 50 in the refrigeration cycle and by continuously releasing the refrigerant pressure at the outlet (second piping 20B) of the compressor 50.

[0075] Furthermore, in the refrigerated vehicle system 10 according to the first embodiment, the control unit 30 stops the refrigerator 20 when the brake negative pressure is equal to or less than a predetermined threshold value when the brakes are applied, so that the refrigerator 20 is not stopped when the brakes are not applied, thereby shortening the stop time of the refrigerator 20. This makes it possible to suppress a rise in temperature of the refrigerator 20.

[0076] Furthermore, in the refrigeration vehicle system 10 according to the first embodiment, when the brake operation signal is turned off, the control unit 30 restarts the refrigerator 20 after the time T1 has elapsed since the brake operation signal was turned off. This ensures time for the brake negative pressure to recover and also ensures time required for the refrigerant pressures at the outlet (second piping 20B) and inlet (first piping 20A) of the compressor 50 in the refrigeration cycle to be equalized, thereby reducing the load on the compressor 50 when it is restarted. Furthermore, by optimizing this time T1, the stop time of the refrigerator 20 can be shortened, thereby suppressing a temperature rise in the refrigerator 20.

[0077] Furthermore, in the refrigeration vehicle system 10 according to the first embodiment, the control unit 30 stops the refrigerator 20 when the brake negative pressure is equal to or less than a predetermined threshold when the brake is applied, and restarts the refrigerator 20 when the brake is released. Therefore, when the brake is released, no brake operation force is required, and restarting the refrigerator 20 can shorten the stop time of the refrigerator 20. This allows the cooling performance of the refrigerator 20 to be maintained.

[0078] Furthermore, in the refrigeration vehicle system 10 according to the first embodiment, the control unit 30 turns off the defrost valve 70 after the time T2 has elapsed since the compressor clutch 52 was turned off. This allows the refrigerant pressure at the outlet (second pipe 20B) of the compressor 50 in the refrigeration cycle to be released, thereby further reducing the load on the compressor 50 when it is restarted.

[0079] Furthermore, in the refrigeration vehicle system 10 according to the first embodiment, the notification unit 18 notifies the driver that more brake application force is required than usual when the brake negative pressure is below a predetermined threshold, so that the driver can recognize that more brake application force is required than usual, i.e., that the brake negative pressure is insufficient.

[0080] Furthermore, in the refrigerated vehicle system 10 according to the first embodiment, the notification unit 18 notifies the driver that more brake operation force is required than usual if the brake negative pressure is equal to or less than a predetermined threshold for a predetermined time T3 when the brakes are applied. This makes it possible to prevent unnecessary notifications to the driver when the brake negative pressure drops due to reasons other than braking, or when the brake negative pressure drops for a short period of time during braking but has little effect on the brake operation force.

[0081] Next, the timing of the control process of the control unit 30 in a modification of the refrigerated vehicle system 10 according to the first embodiment will be described. FIG. 8 is a diagram showing an example of the timing of the control process of the control unit 30 according to the modification of the first embodiment. In the first embodiment, as shown in FIG. 6, the control unit 30 turns on the compressor clutch 52 to restart the refrigerator 20 after time T1 has elapsed since the brake operation signal was turned off. In contrast, in the modification, as shown in FIG. 8, the control unit 30 turns on the compressor clutch 52 to restart the refrigerator 20 after time T1 has elapsed since the brake negative pressure signal was turned off. Note that in the modification shown in FIG. 8, time T1 may be a value different from that shown in FIG. 6, and an optimized time can be set.

[0082] 9 is a flowchart showing an example of control processing by the control unit according to a modification of the refrigerated vehicle system 10 according to the first embodiment. In the following description, a detailed description of the processing by the control unit 30 that is the same as that in the flowchart of FIG. 5 may be omitted.

[0083] As shown in Fig. 9, in step S21, the control unit 30 determines whether or not a brake operation has started. If a brake operation has been started (step S21; YES), in step S22, the control unit 30 determines whether or not the brake negative pressure is equal to or less than a predetermined threshold. If the brake negative pressure is equal to or less than the predetermined threshold (step S22; YES), in step S23, the control unit 30 determines that the brake operation force required for braking will increase, and stops the refrigerator 20. At this time, the control unit 30 controls the opening and closing of each valve element of the freezing valve 60 and the defrosting valve 70, as shown in Fig. 8.

[0084] If the braking operation has not started in step S21 (step S21; NO), the control unit 30 performs the process of step S21 until the braking operation is started. If the braking operation has not started in step S21 (step S21; NO), the control unit 30 proceeds to step S28 and performs the processes from step S28 onwards.

[0085] Next, after the refrigerator 20 is stopped in step S23, the control unit 30 determines in step S24 whether the brake negative pressure has recovered. If the brake negative pressure has not recovered (step S24; NO), in step S25 the control unit 30 continues to stop the refrigerator 20. In addition, in step S26, the control unit 30 warns the driver via the notification unit 18 that more brake operation force than usual is required, and then the process proceeds to step S24.

[0086] On the other hand, if the brake negative pressure is recovered in step S24 (step S24; YES), in step S27 the control unit 30 restarts the refrigerator 20. After the refrigerator 20 is restarted in step S27, in step S28 the control unit 30 determines whether or not the brake operation is continuing. If the brake operation is continuing (step S28; YES), the control unit 30 proceeds to step S22 and performs the processes from step S22 onwards.

[0087] Furthermore, if the brake operation is not continuing in step S28 (step S28; NO), in step S29 the control unit 30 determines whether or not the refrigerated vehicle body 12 has stopped. If the refrigerated vehicle body 12 has stopped in step S29 (step S29; YES), the control unit 30 ends all processing. On the other hand, if the refrigerated vehicle body 12 has not stopped in step S29 (step S29; NO), the control unit 30 shifts processing to step S21 and continues processing from step S11 onwards.

[0088] Next, the operation and effects of the modified example of the first embodiment will be described.

[0089] In the refrigeration vehicle system 10 according to the modification of the first embodiment, when the brake negative pressure is greater than a predetermined threshold, i.e., when the brake negative pressure is restored, the control unit 30 restarts the refrigerator 20 after the lapse of time T1. Therefore, the load on the compressor 50 when it is restarted can be reduced by ensuring time for the brake negative pressure to be restored and also ensuring time required for the refrigerant pressure to be equalized at the outlet (second pipe 20B) and inlet (first pipe 20A) of the compressor 50 in the refrigeration cycle.

[0090] Next, a refrigerated vehicle system 10A according to a second embodiment of the present invention will be described. In the refrigerated vehicle system 10A according to this embodiment, the same components as those in the refrigerated vehicle system 10 according to the first embodiment will be designated by the same reference numerals and will not be described again, and only the differences will be described in detail. Figure 10 is a block diagram schematically showing the control configuration including the control unit 30 of the refrigerated vehicle system 10A according to the second embodiment.

[0091] 10, the refrigeration vehicle system 10A of this embodiment further includes a vacuum tank 19 in addition to the configuration of the refrigeration vehicle system 10 of the first embodiment. The vacuum tank 19 is a tank that accumulates negative pressure gas that is lower than atmospheric pressure, and as an example, the brake booster 43 is connected to a negative pressure generating pipe (not shown) that takes in engine negative pressure from the engine 16. The control unit 30 supplies the negative pressure accumulated in the vacuum tank 19 to the brake booster 43 by operating an electromagnetic valve (not shown) arranged between the brake booster 43 and the vacuum tank 19. Note that the supply of negative pressure from the vacuum tank 19 to the brake booster 43 is performed, as an example, at the same time that engine negative pressure is supplied from the engine 16.

[0092] Next, the operation and effects of the second embodiment will be described.

[0093] In the refrigerated vehicle system 10A according to the second embodiment, the control unit 30 activates the brake booster 43 by utilizing the negative pressure in the vacuum tank 19 when the brake negative pressure is equal to or lower than a predetermined threshold. This makes it possible to prevent a decrease in the brake negative pressure even after multiple brake operations. This ensures a sufficient brake negative pressure compared to when the vacuum tank 19 is not provided, thereby preventing an increase in the operating force required for braking, which is unique to refrigerated vehicles.

[0094] [Supplementary explanation of the embodiment] In the above-described embodiment, the control unit 30 stops the refrigerator 20 when the brake negative pressure falls below a predetermined threshold, but the present invention is not limited to this. Fig. 11 is a graph showing the relationship between the brake operation force and the brake negative pressure. As shown in Fig. 11, the control unit 30 stops the refrigerator 20 when the brake negative pressure falls below a predetermined threshold and the brake operation force also falls below a predetermined threshold. The predetermined threshold is set in advance based on statistics of the value at which the driver feels that the brake pedal 42 is heavy.

[0095] Furthermore, the detection of the brake operation force is, for example, based on a signal output from a hydraulic sensor (not shown) that detects the hydraulic pressure of the master cylinder 44. The detection of the brake operation force is not limited to a hydraulic sensor, and for example, an operating signal of an antilock brake system (ABC) or an existing signal may be used.

[0096] In this way, by stopping the refrigerator 20 when the brake negative pressure falls below a predetermined threshold and the brake operating force falls below a predetermined threshold, the stop time of the refrigerator 20 can be shortened compared to when the refrigerator 20 is stopped when the brake negative pressure falls below a predetermined threshold, and the refrigeration performance of the refrigerator 20 can be ensured.

[0097] In the above-described embodiment, the control unit 30 stops the refrigerator 20 when a braking operation has started and the brake negative pressure is equal to or less than a predetermined threshold, but the present invention is not limited to this. The control unit 30 may also stop the refrigerator 20 when the brake negative pressure is equal to or less than a predetermined threshold even when a braking operation has not started.

[0098] In the first embodiment, the control unit 30 turns on the compressor clutch 52 and restarts the refrigerator 20 after the time T1 has elapsed since the brake operation signal was turned on, but the present invention is not limited to this. The control unit 30 may restart the refrigerator 20 before the time T1 has elapsed since the brake operation signal was turned on.

[0099] In the second embodiment, the control unit 30 turns on the compressor clutch 52 and restarts the refrigerator 20 after the time T1 has elapsed since the brake negative pressure signal was turned on, but the present invention is not limited to this. The control unit 30 may also restart the refrigerator 20 before the time T1 has elapsed since the brake negative pressure signal was turned on.

[0100] In the embodiment described above, the control unit 30 turns on the defrost valve 70 after the time T2 has elapsed since the compressor clutch 52 was turned on, but the present invention is not limited to this. The control unit 30 may turn on the defrost valve 70 before the time T2 has elapsed since the compressor clutch 52 was turned on.

[0101] Furthermore, in the above-described embodiment, the notification unit 18 is provided, but the present invention is not limited to this, and the notification unit 18 may not be provided. In this case, in Fig. 5, if the brake negative pressure has not recovered in step S17 (step S17; NO), the control unit 30 does not perform the process of step S19, but shifts the process to step S11 and performs the processes from step S11 onwards. Also, in Fig. 9, the control unit 30 does not perform the process of step S26, but shifts the process to step S24.

[0102] Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment may be appropriately combined with various modified examples, and the present invention may of course be embodied in various forms as long as it does not deviate from the gist of the present invention. [Explanation of symbols]

[0103] 10 Refrigerated Vehicle System 12 Refrigerated vehicle body (vehicle) 14A Luggage compartment 16 Engine 18. Information Department 19 Vacuum Tank 20 Refrigeration Machine 30 Control unit (brake negative pressure control device for refrigerated vehicle) 43 Brake booster 60 Refrigeration Valve 70 Defrost valve

Claims

1. A vacuum brake booster that uses engine negative pressure to reduce braking force; a refrigeration unit provided in a luggage compartment of the vehicle; a control unit that stops the refrigerator when the brake negative pressure in the brake booster is equal to or lower than a predetermined threshold, the refrigerator includes a freezing valve that is opened during a freezing operation and a defrosting valve that is opened during a defrosting operation, The control unit stops the refrigerator and opens the freeze valve and the defrost valve when the brake negative pressure is equal to or less than the predetermined threshold.

2. A vacuum brake booster that uses engine negative pressure to reduce braking force; a refrigeration unit provided in a luggage compartment of the vehicle; a control unit that stops the refrigerator when the brake negative pressure in the brake booster is equal to or lower than a predetermined threshold; a vacuum tank that accumulates gas at a negative pressure lower than atmospheric pressure; Including, The control unit activates the brake booster by utilizing the negative pressure in the vacuum tank when the brake negative pressure is equal to or less than the predetermined threshold.

3. Equipped with a vacuum tank that accumulates gas at a negative pressure lower than atmospheric pressure, The refrigeration vehicle system according to claim 1 , wherein the control unit activates the brake booster by utilizing the negative pressure in the vacuum tank when the brake negative pressure is equal to or less than the predetermined threshold value.

4. 3. The refrigeration vehicle system according to claim 1, further comprising a notification unit that notifies the driver that a greater brake operation force than normal is required when the brake negative pressure is equal to or less than the predetermined threshold value.

5. The refrigeration vehicle system according to claim 4, wherein the notification unit issues a notification when the brake negative pressure is equal to or less than the predetermined threshold value for a predetermined period of time when the brake is applied.

6. 3. The refrigerated vehicle system according to claim 1, wherein the control unit stops the refrigerator when the brake negative pressure is equal to or less than a predetermined threshold value when the brake is applied.

7. 3. The refrigerated vehicle system according to claim 1, wherein the control unit restarts the refrigerator after a predetermined time has elapsed when the brake negative pressure is greater than a predetermined threshold value.

8. 3. The refrigeration vehicle system according to claim 1, wherein the control unit stops the refrigerator when the brake negative pressure is equal to or less than a predetermined threshold when the brake is applied, and restarts the refrigerator when the brake is released.

9. A brake negative pressure control device for a refrigerated vehicle equipped with a brake booster that uses engine negative pressure to assist brake operation force and a refrigeration unit in the luggage compartment that is equipped with a freezing valve that is opened during freezing operation and a defrosting valve that is opened during defrosting operation, when the brake negative pressure in the brake booster is below a predetermined threshold, stops the refrigeration unit and opens the freezing valve and the defrosting valve.

10. A brake negative pressure control device for a refrigerated vehicle equipped with a brake booster that utilizes engine negative pressure to assist brake operation force, a vacuum tank that accumulates gas at a negative pressure lower than atmospheric pressure, and a refrigerator installed in the luggage compartment, which stops the refrigerator and activates the brake booster using the negative pressure in the vacuum tank when the brake negative pressure in the brake booster is below a predetermined threshold.

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