JP7614574B2 - Vehicle refrigeration cycle device - Google Patents

Description

The present invention relates to a refrigeration cycle device for use in a vehicle that runs on a gasoline engine.

Conventionally, the vehicle refrigeration cycle device described in Patent Document 1 is mounted on a vehicle having a brake booster. The brake booster accumulates the negative pressure generated in the intake system of the vehicle's gasoline engine as a brake negative pressure, and is driven by the brake negative pressure to reduce the driver's brake pedal operation force.

Here, the vehicle's gasoline engine is subjected to not only the load caused by driving, but also loads from the automatic transmission, compressor, alternator, etc. If these loads increase while the vehicle's gasoline engine is idling, the idle speed control operates in the direction of opening the throttle valve to maintain the rotation speed of the vehicle's gasoline engine, reducing the intake vacuum and the brake vacuum.

In particular, in vehicles such as refrigerated vehicles that have two refrigeration cycle devices, one for the passenger compartment air conditioning and one for the luggage compartment air conditioning, the load on the vehicle's gasoline engine is likely to be large because there are two compressors, one for the passenger compartment air conditioning refrigeration cycle device and one for the luggage compartment air conditioning refrigeration cycle device. This means that the intake negative pressure tends to be small, and the brake negative pressure also tends to be small.

In this regard, the vehicle refrigeration cycle device described in the above Patent Document 1 is designed to stop operation of the vehicle refrigeration cycle device when the brake negative pressure does not reach the value required to operate the brake booster.

Specifically, the load on the vehicle engine is reduced by stopping the compressor driven by the vehicle's gasoline engine, which reduces the amount of intake air into the vehicle's gasoline engine and controls the throttle valve to the closed side. This increases the intake negative pressure, ensuring the brake negative pressure required to drive the brake booster.

JP 2000-73810 A

However, in the above conventional technology, when the brake negative pressure does not reach the value required to activate the brake booster, the compressor is stopped even if the brake pedal is not depressed, which means that the compressor (on-board equipment) is stopped more than necessary.

In addition, when the compressor is restarted after being stopped, it may be restarted while the pressure inside the compressor is high, which may result in a loud operating noise when connecting the engine and compressor with the magnetic clutch, or the magnetic clutch may slip, resulting in significant wear on the magnetic clutch.

In view of the above, an object of the present invention is to reduce the frequency of compressor stoppage and to facilitate smooth restarting of the compressor.

In order to achieve the above object , the present invention provides:
a compressor (21) driven by a gasoline engine (2) for sucking, compressing and discharging a refrigerant;
a radiator (22) for radiating heat from a refrigerant discharged from a compressor (21);
a pressure reducing section (23) for reducing the pressure of the refrigerant whose heat has been radiated by the radiator (22);
an evaporator (123) for evaporating the refrigerant decompressed in the decompression section (23);
a pressure equalizing section (28) for equalizing pressure by communicating the suction side and the discharge side of the compressor (21);
a pressure equalizing valve (26) for opening and closing the pressure equalizing section (28);
a control unit (40) for controlling a magnetic clutch that interrupts the transmission of driving force from the gasoline engine (2) to the compressor (21) and a pressure equalizing valve (26);
When a brake pedal, the operating force of which is reduced by a brake booster that utilizes the negative pressure of the intake air of the gasoline engine (2), is depressed and the negative pressure of the intake air of the gasoline engine (2) is smaller than a predetermined value, the control unit (40) performs engine load control that controls a magnetic clutch so that the driving force from the gasoline engine (2) is cut off and the compressor (21) stops, and also performs pressure equalization control that opens a pressure equalization valve (26) so that the intake side and discharge side of the compressor (21) are connected.

According to this, the compressor (21) is stopped when the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine (2) is smaller than a predetermined value, so it is possible to avoid stopping the compressor (21) when the brake pedal is not depressed.

In addition, when the negative pressure of the intake air of the gasoline engine (2) is lower than a predetermined value and the brake pedal is depressed, the equalizing valve (26) is opened, so that the high and low pressures of the refrigeration cycle can be equalized while the compressor (21) is stopped. Therefore, the compressor (21) can be driven again with the pressure inside the compressor (21) as low as possible, so that it is possible to suppress loud operating noise when connecting the gasoline engine (2) and the compressor (21) with the magnetic clutch, and to suppress wear due to slippage of the magnetic clutch.

As a result of the above, it is possible to reduce the frequency of stopping the compressor (21) and facilitate restarting the compressor (21).

In the invention described in claim 2, in the vehicle refrigeration cycle device described in claim 1, the control unit (40) controls the magnetic clutch so that the driving force is transmitted to the compressor (21) when the stop time of the compressor (21) during the engine load control becomes equal to or longer than a predetermined stop time (T1), and ends the engine load control. This allows the compressor (21) to be driven again with simple control.

In the invention described in claim 3, in the vehicle refrigeration cycle device described in claim 1 or 2, the control unit (40) closes the pressure equalizing valve (26) and ends the pressure equalizing control when the opening time of the pressure equalizing valve (26) during the pressure equalizing control becomes equal to or longer than a predetermined opening time (T2).

This allows the pressure equalizing valve (26) to be closed with simple control, returning the refrigeration cycle to normal operation.

In the vehicle refrigeration cycle device according to the present invention, the control unit (40)
When the stop time of the compressor (21) during the engine load control reaches or exceeds a predetermined stop time (T1), the magnetic clutch is controlled so that the driving force is transmitted to the compressor (21) to terminate the engine load control;
In the pressure equalization control, when the open time of the pressure equalization valve (26) reaches or exceeds a predetermined open time (T2) that is longer than a predetermined stop time (T1), the pressure equalization valve (26) is closed to terminate the pressure equalization control.

This makes it possible to prevent the pressure equalization control from ending before the compressor (21) is restarted, so that the high and low pressures of the refrigeration cycle can be equalized before the compressor (21) is restarted.

In accordance with a fifth aspect of the present invention, in the vehicle refrigeration cycle device according to any one of the first to fourth aspects,
a bypass section (27) for directing a refrigerant discharged from the compressor (21) to an evaporator, bypassing the radiator (22) and the pressure reducing section (23);
a bypass valve (25) for opening and closing the bypass portion (27);
In the pressure equalization control, the control unit (40) opens the pressure equalization valve (26) and also opens the bypass valve (25) so that the refrigerant discharged from the compressor (21) bypasses the radiator (22) and the pressure reduction unit (23) and is guided to the evaporator (123).

This ensures that the high and low pressures of the refrigeration cycle are equalized through the bypass section (27).

In the invention described in claim 6, in the vehicle refrigeration cycle device described in claim 5, when the opening time of the pressure equalizing valve (26) during pressure equalization control becomes equal to or longer than a predetermined opening time (T2), the control unit (40) closes the pressure equalizing valve (26) and closes the bypass valve (25) to terminate the pressure equalization control.

This allows the pressure equalizing valve (26) and bypass valve (25) to be closed with simple control, returning the refrigeration cycle to normal operation.

Note that the symbols in parentheses for each means described in this section and in the claims indicate the corresponding relationship with the specific means described in the embodiments described below.

FIG. 1 is a schematic diagram illustrating a transportation vehicle according to an embodiment. FIG. 2 is an overall configuration diagram of a luggage compartment air-conditioning and refrigeration cycle device used in the transport vehicle of FIG. 1. 3 is a block diagram showing an electronic control unit in the luggage compartment air-conditioning and refrigeration cycle device of FIG. 2. 4 is a time chart illustrating a control process executed by the control device of FIG. 3 .

One embodiment will be described below. Figure 1 is a cross-sectional view showing a transport vehicle 1 on which a vehicle refrigeration cycle device according to this embodiment is mounted. In Figure 1, the up, down, front, and rear arrows indicate the up, down, front, and rear directions of the transport vehicle 1.

The transport vehicle 1 of this embodiment has a loading platform 11 behind the driver's cab 10 located at the very front of the vehicle. The loading platform 11 is formed in a box shape using a heat insulating material or the like. A luggage compartment 111 is formed within the loading platform 11.

Mounted below the driver's cab 10 are a gasoline engine 2 that runs on gasoline, an automatic transmission 3 that is a speed change mechanism, and an alternator 4 that is a generator. The gasoline engine 2 is an internal combustion engine that has a throttle valve that adjusts the amount of intake air. The vehicle is provided with a brake booster (not shown) that reduces the force required when the driver depresses the brake pedal (not shown).

The brake booster uses the negative pressure of the intake air of the gasoline engine 2 to reduce the force required to depress the brake pedal. A negative pressure passage extending from the intake pipe of the gasoline engine 2 is connected to the brake booster. The negative pressure passage extends from a portion of the intake pipe of the gasoline engine 2 downstream of the throttle valve. An intake pressure sensor 47 that detects the intake pressure of the gasoline engine 2 is disposed in the negative pressure passage.

The negative pressure in the intake passage draws air from inside the brake booster through the negative pressure passage, and this air suction creates negative pressure in the brake booster. The brake booster is driven by the negative pressure created in the brake booster.

Although not shown in the figure, the side and rear parts of the loading platform 11 are provided with openings for loading and unloading luggage, and doors for opening and closing these openings. A loading compartment air conditioning unit 12 is arranged in the loading compartment 111.

As shown by arrows A1 and A2 in FIG. 1, the luggage compartment air conditioning unit 12 draws in air from the luggage compartment 111, cools it, and blows it out into the luggage compartment 111. The temperature inside the luggage compartment 111 is adjusted by the air blown out from the luggage compartment air conditioning unit 12.

The unit case 121 of the luggage compartment air conditioning unit 12 houses a first interior blower 122 and a first evaporator 123. The first interior blower 122 is an electric blower driven by an electric motor.

When the first indoor blower 122 is operated, air in the luggage compartment 111 is sucked into the unit case 121 and cooled as it passes through the first evaporator 123, and the cool air that has passed through the first evaporator 123 is blown out from the unit case 121 into the luggage compartment 111. This cools the air in the luggage compartment 111 and refrigerates or freezes the luggage in the luggage compartment 111.

A cab air conditioning unit 13 is arranged in the cab 10. The cab air conditioning unit 13 draws in air inside the cab 10 or outside air, cools or heats it, and blows it out into the cab 10. The temperature of the cab 10 is adjusted by the air blown out from the cab air conditioning unit 13.

The unit case 131 of the cab air conditioning unit 13 houses a second exterior blower 132 and a second evaporator 133. The second exterior blower 132 is an electric blower driven by an electric motor.

When the second exterior blower 132 is activated, air in the cab 10 or outside air is drawn into the unit case 131 and cooled as it passes through the second evaporator 133.

The unit case 131 also houses a heater core (not shown) and an air mix door (not shown). The heater core heats the air that has passed through the second evaporator 133 by exchanging heat with the engine coolant. The air mix door adjusts the temperature of the air blown into the passenger compartment by adjusting the ratio of the airflow between the air that flows through the heater core and the air that bypasses the heater core.

The air that passes through the second evaporator 133 and the heater core is blown out from the unit case 131 into the cab 10, as shown by arrow A3 in Figure 1.

Figure 2 is an overall configuration diagram of the luggage compartment air conditioning refrigeration cycle device 20 mounted on the transportation vehicle 1 of Figure 1. The luggage compartment air conditioning refrigeration cycle device 20 includes a first compressor 21, a first condenser 22, a first expansion valve 23, a first evaporator 123, a first bypass valve 25, and a first pressure equalizing valve 26.

The first compressor 21 compresses the sucked refrigerant and discharges it. For example, the first compressor 21 is disposed in the engine compartment of the vehicle.

For example, the first compressor 21 is an engine-driven compressor that is rotationally driven by the gasoline engine 2 via a first magnetic clutch (not shown). The first magnetic clutch is a driving force interrupter that interrupts the driving force transmitted from the gasoline engine 2 to the first compressor 21.

The cargo compartment air conditioning refrigeration cycle device 20 uses an HFC refrigerant (specifically, R134a) as the refrigerant, and forms a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigeration oil to lubricate the first compressor 21. A portion of the refrigeration oil circulates through the refrigerant circuit of the refrigeration cycle device together with the refrigerant.

The first condenser 22 is connected to the discharge side of the first compressor 21. The first condenser 22 exchanges heat between the high-pressure refrigerant (gas refrigerant) discharged from the first compressor 21 and outside air (air outside the vehicle cabin) blown by a first exterior blower (not shown), thereby cooling and condensing the high-pressure refrigerant. The first condenser 22 is a radiator that dissipates heat from the refrigerant. The first exterior blower is an electric blower driven by an electric motor.

A first expansion valve 23 is connected to the outlet side of the first condenser 22. The first expansion valve 23 is a first pressure reducing section that reduces the pressure of the high-pressure refrigerant (liquid refrigerant) condensed in the first condenser 22.

For example, the first expansion valve 23 is a temperature-type expansion valve, has a temperature sensor that detects the degree of superheat of the refrigerant on the outlet side of the first evaporator 123 based on the temperature and pressure of the refrigerant on the outlet side of the first evaporator 123, and adjusts the throttle passage area by a mechanical mechanism so that the degree of superheat of the refrigerant on the outlet side of the first evaporator 123 is within a predetermined range. The first expansion valve 23 may be an electric expansion valve that adjusts the throttle passage area by an electrical mechanism.

The first evaporator 123 is connected to the outlet side of the first expansion valve 23. Low-pressure refrigerant (liquid refrigerant) decompressed by the first expansion valve 23 flows into the first evaporator 123, and this low-pressure refrigerant absorbs heat from the air blown by the first indoor blower 122 and evaporates, thereby cooling the air. The low-pressure refrigerant (gas refrigerant) evaporated in the first evaporator 123 is sucked into the first compressor 21.

A first bypass flow path 27 is connected to the discharge side of the first compressor 21 and the inlet side of the first evaporator 123. The first bypass flow path 27 is a bypass section through which the high-temperature refrigerant (hot gas) discharged from the first compressor 21 flows, bypassing the first condenser 22 and the first expansion valve 23. A first bypass valve 25 is disposed in the first bypass flow path 27. The first bypass valve 25 is a bypass opening/closing section that opens and closes the first bypass flow path 27.

A first pressure equalizing flow passage 28 is connected between the suction side of the first compressor 21 and the discharge side of the first compressor 21. The first pressure equalizing flow passage 28 is a pressure equalizing section that connects the suction side of the first compressor 21 and the discharge side of the first compressor 21 to achieve pressure equalization. A first pressure equalizing valve 26 is disposed in the first pressure equalizing flow passage 28. The first pressure equalizing valve 26 is a pressure equalizing flow passage opening/closing section that opens and closes the first pressure equalizing flow passage 28.

The first bypass valve 25 and the first pressure equalizing valve 26 are solenoid valves whose operation is controlled by a control signal output from the control device 40.

The configuration of the cab air conditioning refrigeration cycle device 30 mounted on the transport vehicle 1 in FIG. 1 is similar to the configuration of the luggage compartment air conditioning refrigeration cycle device 20. Therefore, in FIG. 2, the reference numeral corresponding to the cab air conditioning refrigeration cycle device 30 is shown in parentheses, and the cab air conditioning refrigeration cycle device 30 is not shown.

The cab air conditioning refrigeration cycle device 30 includes a second compressor 31, a second condenser 32, a second expansion valve 33, a second evaporator 133, a second bypass valve 35, and a second pressure equalizing valve 36.

The second compressor 31 compresses the sucked refrigerant and discharges it. For example, the second compressor 31 is disposed in the engine compartment of the vehicle.

For example, the second compressor 31 is an engine-driven compressor that is rotationally driven by a vehicle engine (not shown) via a second magnetic clutch (not shown). The second magnetic clutch is a driving force interrupter that interrupts the driving force transmitted from the gasoline engine 2 to the second compressor 31.

The cab air conditioning refrigeration cycle device 30 uses an HFC refrigerant (specifically, R134a) as the refrigerant, and forms a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigeration oil to lubricate the second compressor 31. A portion of the refrigeration oil circulates through the refrigerant circuit of the refrigeration cycle device together with the refrigerant.

The second condenser 32 is connected to the discharge side of the second compressor 31. The second condenser 32 exchanges heat between the high-pressure refrigerant (gas refrigerant) discharged from the second compressor 31 and outside air (air outside the vehicle cabin) blown by a second exterior blower (not shown), thereby cooling and condensing the high-pressure refrigerant. The second condenser 32 is a radiator that dissipates heat from the refrigerant. The second exterior blower is an electric blower driven by an electric motor.

A second expansion valve 33 is connected to the outlet side of the second condenser 32. The second expansion valve 33 is a second pressure reduction section that reduces the pressure of the high-pressure refrigerant (liquid refrigerant) condensed in the second condenser 32.

For example, the second expansion valve 33 is a temperature-type expansion valve, has a temperature sensor that detects the degree of superheat of the refrigerant on the outlet side of the second evaporator 133 based on the temperature and pressure of the refrigerant on the outlet side of the second evaporator 133, and adjusts the throttle passage area by a mechanical mechanism so that the degree of superheat of the refrigerant on the outlet side of the second evaporator 133 is within a predetermined range. The second expansion valve 33 may be an electric expansion valve that adjusts the throttle passage area by an electrical mechanism.

The second evaporator 133 is connected to the outlet side of the second expansion valve 33. Low-pressure refrigerant (liquid refrigerant) decompressed by the second expansion valve 33 flows into the second evaporator 133, and this low-pressure refrigerant absorbs heat from the air blown by the second outdoor blower 132 and evaporates, thereby cooling the air. The low-pressure refrigerant (gas refrigerant) evaporated in the second evaporator 133 is sucked into the second compressor 31.

A second bypass flow path 37 is connected between the discharge side of the second compressor 31 and the inlet side of the second evaporator 133. The second bypass flow path 37 is a bypass section through which the high-temperature refrigerant (hot gas) discharged from the second compressor 31 flows, bypassing the second condenser 32 and the second expansion valve 33. A second bypass valve 35 is disposed in the second bypass flow path 37. The second bypass valve 35 is a bypass opening/closing section that opens and closes the second bypass flow path 37.

A second pressure equalizing flow passage 38 is connected to the suction side of the second compressor 31 and the discharge side of the second compressor 31. The second pressure equalizing flow passage 38 is a pressure equalizing section that connects the suction side of the second compressor 31 and the discharge side of the second compressor 31 to equalize the pressure. A second pressure equalizing valve 36 is disposed in the second pressure equalizing flow passage 38. The second pressure equalizing valve 36 is a pressure equalizing flow passage opening/closing section that opens and closes the second pressure equalizing flow passage 38.

The second bypass valve 35 and the second pressure equalizing valve 36 are solenoid valves whose operation is controlled by a control signal output from the control device 40.

The control device 40 is composed of a well-known microcomputer consisting of a CPU, ROM, RAM, etc., and its peripheral circuits, and performs various calculations and processing based on the control program stored in the ROM.

The control device 40 is a control unit that controls the operation of the first indoor blower 122, the first outdoor blower, the first compressor 21, the first bypass valve 25, the first pressure equalizing valve 26, the second outdoor blower 132, the second outdoor blower, the second compressor 31, the second bypass valve 35, and the second pressure equalizing valve 36, which are connected to the output side. The control device 40 constitutes an in-vehicle equipment control device that controls in-vehicle equipment such as the first compressor 21 and the second compressor 31.

As shown in FIG. 3, various control sensors and various control switches are connected to the input side of the control device 40. The various control sensors include a luggage compartment temperature sensor 41, a vehicle compartment temperature sensor 42, an outside air temperature sensor 43, a solar radiation sensor 44, a first evaporator temperature sensor 45, a second evaporator temperature sensor 46, an intake pressure sensor 47, etc. The various control switches include a brake switch 48, etc.

The luggage compartment temperature sensor 41 detects the temperature inside the luggage compartment 111. The vehicle interior temperature sensor 42 detects the temperature inside the vehicle interior. The outside air temperature sensor 43 detects the outside air temperature. The solar radiation sensor 44 detects the amount of solar radiation inside the vehicle interior.

The first evaporator temperature sensor 45 is an evaporator temperature detection unit that detects the refrigerant evaporation temperature (first evaporator temperature) in the first evaporator 123. The first evaporator temperature sensor 45 detects the heat exchange fin temperature of the first evaporator 123 and the temperature of the refrigerant on the outlet side of the first evaporator 123.

The second evaporator temperature sensor 46 is an evaporator temperature detection unit that detects the refrigerant evaporation temperature (second evaporator temperature) in the second evaporator 133. The second evaporator temperature sensor 46 detects the heat exchange fin temperature of the second evaporator 133 and the temperature of the refrigerant on the outlet side of the second evaporator 133.

The intake pressure sensor 47 is an intake pressure detection unit that detects the intake pressure of the gasoline engine 2. The brake switch 48 is a brake depression detection unit that detects the depression of the brake pedal by the driver.

Various operation signals are input to the control device 40 from the operation panel 50. The operation panel 50 is located near the instrument panel inside the vehicle cabin. The operation panel 50 is provided with a cargo compartment air conditioning operation switch for switching the operation/stop of the cargo compartment air conditioning refrigeration cycle device 20 (specifically, the operation/stop of the first compressor 21), a cab air conditioning operation switch for switching the operation/stop of the cab air conditioning refrigeration cycle device 30 (specifically, the operation/stop of the second compressor 31), a cargo compartment target temperature setting switch for setting the target temperature in the cargo compartment 111, a cab target temperature setting switch for setting the target temperature in the cab 10, and the like.

Next, the operation of the above configuration will be described. When the cargo compartment air conditioning operation switch on the operation panel 50 is turned on, the first compressor 21 operates to operate the cargo compartment air conditioning refrigeration cycle device 20. During normal operation of the cargo compartment air conditioning refrigeration cycle device 20, the first bypass valve 25 and the first pressure equalizing valve 26 are closed.

When the first compressor 21 is operating, the gas refrigerant discharged from the first compressor 21 flows into the first condenser 22, where it is condensed and liquefied, and then the pressure is reduced by the first expansion valve 23 and supplied to the first evaporator 123, so that the air sent to the cargo compartment 111 can be cooled by the first evaporator 123.

The refrigerant discharge amount (in other words, the refrigerant discharge capacity) of the first compressor 21 is controlled based on the temperature in the luggage compartment 111 detected by the luggage compartment temperature sensor 41 and the temperature of the first evaporator 123 detected by the first evaporator temperature sensor 45, etc.

If it is determined that frost has formed on the first evaporator 123, a defrosting operation is performed. For example, if the time during which the temperature of the first evaporator 123 detected by the first evaporator temperature sensor 45 is below the frost determination temperature exceeds the frost determination time, it is determined that frost has formed on the first evaporator 123.

During defrosting operation, the first bypass valve 25 is opened. This allows the high-temperature gas refrigerant discharged from the first compressor 21 to be introduced into the first evaporator 123 through the first bypass passage 27, thereby defrosting the first evaporator 123.

When the cab air conditioning operation switch on the operation panel 50 is turned on, the second compressor 31 operates to operate the cab air conditioning refrigeration cycle device 30. During normal operation of the cab air conditioning refrigeration cycle device 30, the second bypass valve 35 and the second pressure equalizing valve 36 are closed. The gas refrigerant discharged from the second compressor 31 flows into the second condenser 32 and is condensed and liquefied, and then is depressurized by the second expansion valve 33 and supplied to the second evaporator 133, so that the air to be blown to the cab 10 can be cooled by the second evaporator 133.

The refrigerant discharge amount (in other words, the refrigerant discharge capacity) of the second compressor 31 is controlled based on the temperature inside the vehicle cabin detected by the vehicle cabin temperature sensor 42, the outside air temperature detected by the outside air temperature sensor 43, the amount of solar radiation inside the vehicle cabin detected by the solar radiation sensor 44, and the temperature of the second evaporator 133 detected by the second evaporator temperature sensor 46.

If it is determined that frost has formed on the second evaporator 133, a defrosting operation is performed. For example, if the time during which the temperature of the second evaporator 133 detected by the second evaporator temperature sensor 46 is below the frost determination temperature exceeds the frost determination time, it is determined that frost has formed on the second evaporator 133.

During defrosting operation, the second bypass valve 35 is opened. This allows the high-temperature gas refrigerant discharged from the second compressor 31 to be introduced into the second evaporator 133 through the second bypass passage 37, thereby defrosting the second evaporator 133.

Next, the pressure equalization control and engine load control shown in the time chart of Figure 4 will be explained. When the driver depresses the brake pedal and it is determined that the brake negative pressure is insufficient (when it is determined as NG in the time chart of Figure 4), the control device 40 performs pressure equalization control and engine load control.

In this example, it is determined whether the driver is depressing the brake pedal based on the detection signal of the brake switch 48. In this example, if it is determined based on the detection signal of the intake pressure sensor 47 that the intake negative pressure of the gasoline engine 2 is smaller than a predetermined value (i.e., the negative pressure is closer to 0 than the predetermined value), it is determined that the brake negative pressure is insufficient.

Engine load control is a control that stops the first compressor 21 for a predetermined stop time T1. The predetermined stop time T1 is set in advance as the time required for the negative pressure detected by the intake pressure sensor 47 to reach a normal value. The predetermined stop time T1 is, for example, about 2 to 3 seconds.

As the engine load control reduces the load on the gasoline engine 2, the intake negative pressure increases and returns to normal negative pressure.

The pressure equalization control is a control that opens the first pressure equalization valve 26 and the first bypass valve 25 for a predetermined valve opening time T2. The predetermined valve opening time T2 is longer than the predetermined stop time T1. The predetermined valve opening time T2 is, for example, about 5 seconds. When the stop time of the first compressor 21 reaches the predetermined stop time T1, the first compressor 21 is operated.

By performing pressure equalization control while the first compressor 21 is stopped, the high and low pressures of the luggage compartment air conditioning refrigeration cycle device 20 are equalized. The first compressor 21 is restarted with the high and low pressures of the luggage compartment air conditioning refrigeration cycle device 20 in a pressure equalized state, so that the magnetic clutch can be prevented from making loud operating noise or from slipping and wearing out when the first compressor 21 is operated.

When the opening time of the first pressure equalizing valve 26 and the first bypass valve 25 reaches the predetermined opening time T2, the first pressure equalizing valve 26 and the first bypass valve 25 are closed. Since the predetermined opening time T2 is longer than the predetermined stop time T1, the first pressure equalizing valve 26 and the first bypass valve 25 can be prevented from being closed before the first compressor 21 is restarted. Therefore, the high pressure and low pressure of the cargo compartment air conditioning refrigeration cycle device 20 can be reliably equalized before the first compressor 21 is restarted.

In this embodiment, when the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine 2 is less than a predetermined value, the control device 40 performs engine load control to control the magnetic clutch of the first compressor 21 so that the driving force from the gasoline engine 2 is cut off and the first compressor 21 stops, and also performs pressure equalization control to open the first pressure equalization valve 26 so that the intake side and discharge side of the first compressor 21 are connected.

According to this, the first compressor 21 is stopped when the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine 2 is smaller than a predetermined value, so it is possible to avoid stopping the first compressor 21 when the brake pedal is not depressed.

In addition, when the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine 2 is smaller than a predetermined value, the first pressure equalizing valve 26 is opened, so that the high and low pressures of the refrigeration cycle can be equalized while the first compressor 21 is stopped. Therefore, the first compressor 21 can be driven again with the pressure inside the first compressor 21 as low as possible, so that it is possible to suppress loud operating noise when connecting the gasoline engine 2 and the first compressor 21 with the magnetic clutch, and to suppress slippage and wear of the magnetic clutch.

As a result of the above, it is possible to reduce the frequency of stopping the first compressor 21 and facilitate restarting the first compressor 21.

In this embodiment, when the stop time of the first compressor 21 during engine load control becomes equal to or longer than the predetermined stop time T1, the control device 40 controls the magnetic clutch so that the driving force is transmitted to the first compressor 21, and ends the engine load control. This allows the first compressor 21 to be driven again with simple control.

In this embodiment, when the opening time of the first pressure equalizing valve 26 during pressure equalization control becomes equal to or longer than the predetermined opening time T2, the control device 40 closes the first pressure equalizing valve 26 and ends the pressure equalization control. This allows the cargo compartment air conditioning and refrigeration cycle device 20 to return to normal operation by closing the first pressure equalizing valve 26 with simple control.

In this embodiment, the predetermined open time T2 of the first pressure equalizing valve 26 is longer than the predetermined stop time T1 of the first compressor 21. This prevents the first pressure equalizing valve 26 and the first bypass valve 25 from being closed before the first compressor 21 is restarted, so that the high and low pressures of the cargo compartment air conditioning refrigeration cycle device 20 can be reliably equalized before the first compressor 21 is restarted. The high and low pressures of the cargo compartment air conditioning refrigeration cycle device 20 can be equalized before the first compressor 21 is restarted.

In this embodiment, in pressure equalization control, the control device 40 opens the first pressure equalization valve 26 and also opens the first bypass valve 25 so that the refrigerant discharged from the first compressor 21 bypasses the first condenser 22 and the first expansion valve 23 and is guided to the first evaporator 123.

As a result, in pressure equalization control, the high and low pressures of the luggage compartment air conditioning refrigeration cycle device 20 can be equalized through the first bypass flow path 27 as well, so that the high and low pressures of the refrigeration cycle can be reliably equalized.

In this embodiment, when the opening time of the first pressure equalizing valve 26 becomes equal to or longer than the predetermined opening time T2 during pressure equalization control, the control device 40 closes the first pressure equalizing valve 26 and closes the first bypass valve 25 to terminate the pressure equalization control.

This allows the first pressure equalizing valve 26 and the first bypass valve 25 to be closed with simple control, returning the cargo compartment air conditioning and refrigeration cycle device 20 to normal operation.

Other Embodiments
The present invention is not limited to the above-described embodiment, but can be modified in various ways as follows.

(1) In the above embodiment, the engine load control shown in the time chart of FIG. 4 is terminated at the predetermined stop time T1, but the engine load control may also be terminated when the negative pressure of the intake air of the gasoline engine 2 reaches or exceeds a predetermined value.

In the above embodiment, the pressure equalization control shown in the time chart of FIG. 4 ends at the predetermined valve opening time T2, but the pressure equalization control may also be ended when the differential pressure between the high pressure and the low pressure of the cargo compartment air conditioning and refrigeration cycle device 20 becomes equal to or less than a predetermined pressure.

(2) In the above embodiment, the engine load control and pressure equalization control shown in the time chart of FIG. 4 are executed for the luggage compartment air conditioning refrigeration cycle device 20. That is, the engine load control stops the first compressor 21, and the pressure equalization control opens the first pressure equalization valve 26 and the first bypass valve 25.

In contrast, the engine load control and pressure equalization control shown in the time chart of FIG. 4 may be executed for the cab air conditioning refrigeration cycle device 30. That is, the second compressor 31 may be stopped in the engine load control, and the second pressure equalization valve 36 and the second bypass valve 35 may be opened in the pressure equalization control.

(3) In the above-described embodiment, the engine load control is a control that stops the first compressor 21 or the second compressor 31, but the engine load control may also be a control that stops on-board equipment such as the alternator 4, a sub-alternator (not shown), a hydraulic pump (not shown), and a water pump (not shown).

The alternator 4 is a generator driven by the gasoline engine 2. The electricity generated by the alternator 4 is used to charge the vehicle's sub-battery. The sub-alternator is a generator driven by the gasoline engine 2. The electricity generated by the sub-alternator is used to charge the vehicle's sub-battery. The hydraulic pump is a pump that is driven by the gasoline engine 2 to generate hydraulic pressure. The water pump is a pump that is driven by the gasoline engine 2 to circulate cooling water.

In other words, engine load control may be control that stops the on-board equipment that puts a load on the gasoline engine 2. As a result, when the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine 2 is smaller than a predetermined value, the load on the gasoline engine 2 is reduced by stopping the on-board equipment, so that the negative pressure of the intake air pressure increases and returns to normal negative pressure.

When the brake pedal is depressed and the negative pressure of the intake air of the gasoline engine 2 is less than a predetermined value, the on-board equipment is stopped, so the frequency of stopping the on-board equipment can be reduced compared to when the on-board equipment is stopped regardless of whether the brake pedal is depressed when the negative pressure of the intake air of the gasoline engine 2 is less than a predetermined value.

It is desirable that the on-board equipment that is stopped during engine load control is equipment that does not immediately affect the running of the vehicle when stopped. This makes it possible to reduce the frequency with which on-board equipment is stopped without compromising the safety of the running of the vehicle.

(4) In the above-described embodiment, an HFC refrigerant (specifically, R134a) with low ozone depletion potential is used as the refrigerant for the refrigeration cycle device, but this is not limited thereto, and various other refrigerants (for example, so-called new refrigerants with low global warming potential) may be used.

(5) In the above embodiment, the refrigeration cycle devices include a luggage compartment air conditioning refrigeration cycle device 20 and a cab air conditioning refrigeration cycle device 30, but the present invention is not limited to this and may include refrigeration cycle devices for various purposes.

In addition, in the above embodiment, an example of applying the refrigeration cycle device to a transport vehicle 1 has been described, but the application of the refrigeration cycle device to various vehicles is not limited to this.

The features of the vehicle refrigeration cycle device and the vehicle-mounted equipment control device disclosed in this specification are as follows.
(Item 1)
a compressor (21) driven by a gasoline engine (2) for sucking, compressing and discharging a refrigerant;
a radiator (22) for radiating heat from the refrigerant discharged from the compressor (21);
a pressure reducing section (23) for reducing the pressure of the refrigerant whose heat has been radiated by the radiator (22);
an evaporator (123) that evaporates the refrigerant decompressed in the decompression section (23);
a pressure equalizing section (28) for equalizing pressure by communicating the suction side and the discharge side of the compressor (21);
a pressure equalizing valve (26) for opening and closing the pressure equalizing section (28);
a control unit (40) that controls a magnetic clutch that interrupts the transmission of a driving force from the gasoline engine (2) to the compressor (21) and the pressure equalizing valve (26),
The control unit (40) performs engine load control to control the magnetic clutch so that the driving force is cut off and the compressor (21) stops, when a brake pedal, the operating force of which is reduced by a brake booster that utilizes the negative pressure of the intake air of the gasoline engine (2), is depressed and the negative pressure is smaller than a predetermined value, and also performs pressure equalization control to open the pressure equalization valve (26) so that the suction side and discharge side of the compressor (21) communicate with each other.
(Item 2)
2. The vehicle refrigeration cycle device according to claim 1, wherein the control unit (40) controls the magnetic clutch so that the driving force is transmitted to the compressor (21) when a stop time of the compressor (21) becomes equal to or longer than a predetermined stop time (T1) during the engine load control, thereby terminating the engine load control.
(Item 3)
3. The vehicle refrigeration cycle device according to claim 1, wherein the control unit (40) closes the pressure equalizing valve (26) to terminate the pressure equalizing control when an open time of the pressure equalizing valve (26) becomes equal to or longer than a predetermined valve open time (T2) during the pressure equalizing control.
(Item 4)
The control unit (40)
When the stop time of the compressor (21) becomes equal to or longer than a predetermined stop time (T1) in the engine load control, the magnetic clutch is controlled so that the driving force is transmitted to the compressor (21) to terminate the engine load control,
3. The vehicle refrigeration cycle device according to claim 1, wherein, when an open time of the pressure equalizing valve (26) during the pressure equalizing control becomes equal to or longer than a predetermined open time (T2) that is longer than the predetermined stop time (T1), the pressure equalizing valve (26) is closed to terminate the pressure equalizing control.
(Item 5)
a bypass section (27) that guides the refrigerant discharged from the compressor (21) to the evaporator, bypassing the radiator (22) and the pressure reducing section (23);
a bypass valve (25) for opening and closing the bypass portion (27),
5. The vehicle refrigeration cycle device according to any one of items 1 to 4, wherein, in the pressure equalization control, the control unit (40) opens the pressure equalization valve (26) and also opens the bypass valve (25) so that the refrigerant discharged from the compressor (21) bypasses the radiator (22) and the pressure reduction unit (23) and is guided to the evaporator (123).
(Item 6)
6. The vehicle refrigeration cycle device according to claim 5, wherein the control unit (40) closes the pressure equalizing valve (26) and closes the bypass valve (25) when an open time of the pressure equalizing valve (26) becomes equal to or longer than a predetermined open time (T2) during the pressure equalizing control, thereby terminating the pressure equalizing control.
(Item 7)
a compressor (21) driven by a gasoline engine (2) for sucking, compressing and discharging a refrigerant;
a radiator (22) for radiating heat from the refrigerant discharged from the compressor (21);
a pressure reducing section (23) for reducing the pressure of the refrigerant whose heat has been radiated by the radiator (22);
an evaporator (123) that evaporates the refrigerant decompressed in the decompression section (23);
a control unit (40) for controlling a magnetic clutch that interrupts the transmission of driving force from the gasoline engine (2) to the compressor (21);
The control unit (40) performs engine load control to control the magnetic clutch so that the driving force is cut off and the compressor (21) stops when a brake pedal, the operating force of which is reduced by a brake booster that utilizes the negative pressure of the intake air of the gasoline engine (2), is depressed and the negative pressure is smaller than a predetermined value.
(Item 8)
The vehicle-mounted equipment control device includes a control unit (40) that stops vehicle-mounted equipment (4, 21) that applies a load to the gasoline engine (2) when a brake pedal, the operation force of which is reduced by a brake booster that utilizes the negative pressure of the intake air of the gasoline engine (2), is depressed and the negative pressure is smaller than a predetermined value.
(Item 9)
the on-vehicle device is a compressor (21) that is driven by the gasoline engine (2) and draws in, compresses, and discharges a refrigerant from a refrigeration cycle device;
The vehicle-mounted equipment control device according to item 8, wherein when the brake pedal is depressed and the negative pressure is smaller than a predetermined value, the control unit (40) stops the compressor (21) by controlling a magnetic clutch, which interrupts the transmission of driving force from the gasoline engine (2) to the compressor (21), to interrupt the driving force.

21 First compressor (compressor)
22 First condenser (heat radiator)
23 First expansion valve (pressure reducing section)
25 First bypass valve (bypass valve)
26 First pressure equalization valve (pressure equalization valve)
27 First bypass flow path (bypass section)
28 First pressure equalization flow path (pressure equalization section)
40 Control device (control unit)
123 First evaporator (evaporator)

Claims (6)

a compressor (21) driven by a gasoline engine (2) for sucking, compressing and discharging a refrigerant;
a radiator (22) for radiating heat from the refrigerant discharged from the compressor (21);
a pressure reducing section (23) for reducing the pressure of the refrigerant whose heat has been radiated by the radiator (22);
an evaporator (123) that evaporates the refrigerant decompressed in the decompression section (23);
a pressure equalizing section (28) for equalizing pressure by communicating the suction side and the discharge side of the compressor (21);
a pressure equalizing valve (26) for opening and closing the pressure equalizing section (28);
a control unit (40) that controls a magnetic clutch that interrupts the transmission of a driving force from the gasoline engine (2) to the compressor (21) and the pressure equalizing valve (26),
The control unit (40) performs engine load control to control the magnetic clutch so that the driving force is cut off and the compressor (21) stops, when a brake pedal, the operating force of which is reduced by a brake booster that utilizes the negative pressure of the intake air of the gasoline engine (2), is depressed and the negative pressure is smaller than a predetermined value, and also performs pressure equalization control to open the pressure equalization valve (26) so that the suction side and discharge side of the compressor (21) communicate with each other. The vehicle refrigeration cycle device according to claim 1, wherein the control unit (40) controls the magnetic clutch so that the driving force is transmitted to the compressor (21) when the stop time of the compressor (21) during the engine load control becomes equal to or longer than a predetermined stop time (T1), thereby terminating the engine load control. The vehicle refrigeration cycle device according to claim 1, wherein the control unit (40) closes the pressure equalizing valve (26) and terminates the pressure equalizing control when the opening time of the pressure equalizing valve (26) during the pressure equalizing control becomes equal to or longer than a predetermined opening time (T2). The control unit (40)
When the stop time of the compressor (21) becomes equal to or longer than a predetermined stop time (T1) in the engine load control, the magnetic clutch is controlled so that the driving force is transmitted to the compressor (21) to terminate the engine load control,
2. The vehicle refrigeration cycle device according to claim 1, wherein, when an open time of the pressure equalizing valve (26) during the pressure equalizing control reaches or exceeds a predetermined open time (T2) that is longer than the predetermined stop time (T1), the pressure equalizing valve (26) is closed to terminate the pressure equalizing control. a bypass section (27) that guides the refrigerant discharged from the compressor (21) to the evaporator, bypassing the radiator (22) and the pressure reducing section (23);
a bypass valve (25) for opening and closing the bypass portion (27),
5. The vehicle refrigeration cycle device according to claim 1, wherein, in the pressure equalization control, the control unit (40) opens the pressure equalization valve (26) and also opens the bypass valve (25) so that the refrigerant discharged from the compressor (21) bypasses the radiator (22) and the pressure reduction unit (23) and is guided to the evaporator (123). The vehicle refrigeration cycle device according to claim 5, wherein the control unit (40) closes the pressure equalizing valve (26) and closes the bypass valve (25) when the opening time of the pressure equalizing valve (26) during the pressure equalizing control becomes equal to or longer than a predetermined opening time (T2).

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