JPH06117707A - Vehicle air-conditioner - Google Patents

Abstract

PURPOSE:To reduce torque variation when the operation of the air-conditioner is changed over to a stopped state of a compressor and prevent slippage on a snow road during running of a vehicle in a heating operation using gaseous refrigerant of high temperature and high pressure (hot gas) during a freezing cycle. CONSTITUTION:A condensor 11 is arranged at a discharging side of a compressor 10 and a heat exchanger 14 is arranged at a suction side of the compressor 10. A path connecting the compressor 10 to the condensor 11 is provided with an opening or closing valve 18a. A bypassing pipe 20 bypassing from the opening or closing valve 18a to the condensor 11 is provided with a second pressure reducing device 22. During a heating operation, a compression work performed by the compressor 10 becomes a heating calorie included in hot gas and the heat is radiated by the heat exchanger 14. In the case that thermal radiation at the heat exchanger 14 is obviated and the compressor is stopped, the opening or closing valve 18a is opened and the refrigerant is flowed from the compressor 10 toward the condensor 11 for a specified period of time and then the operation of the compressor 10 is continued for a specified period of time. With such an arrangement as mentioned above, torque drop of the compressor 10 is decreased and the torque variation applied from an internal combustion engine to a driving system for running of the vehicle is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to a vehicle air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art In an air conditioner having a refrigeration cycle in which a compressor, a condenser, a pressure reducing device and an evaporator are connected, a stop sound is generally generated when the compressor is stopped. Therefore, for example, Japanese Patent Laid-Open No. 3-195864
In the air conditioner disclosed in the publication, the maximum compression torque value is reduced by lowering the suction pressure of the compressor immediately before stopping the compressor, and then the compressor is stopped, and the stop sound of the vehicle air conditioner is generated. It is decreasing.

[0003]

By the way, as a conventional vehicle air conditioner mounted on a vehicle, a hot water heater utilizing exhaust heat of cooling hot water of an internal combustion engine for running the vehicle is used, for example, as shown in FIG. As shown in FIG. 2, the cooling hot water of the internal combustion engine 1 is introduced into the heater core 3a of the hot water heater 3 through the pipe 2, and the cooling hot water radiated by the heater core 3a is returned to the internal combustion engine 1 through the pipe 4. This hot water heater 3
Is provided on the downstream side of the heat exchanger 14 constituting the cooling device with respect to the flow of air introduced into the vehicle interior.

However, since the heating device utilizing the exhaust heat of the cooling hot water of the internal combustion engine for vehicle running as a heat source has a low cooling water temperature when the internal combustion engine is started at a low temperature, a hot water heater using this cooling water as a heat source. The rise of is bad. Then, in order to solve such a problem, the present applicant improved the heating capacity by using a high-temperature high-pressure gas refrigerant (hot gas) in the refrigeration cycle in addition to the main heating device such as a hot water heater. I applied for a patent for a simple vehicle air conditioner.

However, in such a heating device using hot gas, since the internal combustion engine for running the vehicle is used as the drive source of the compressor, a large torque fluctuation occurs when the compressor is stopped, so the compressor is If the vehicle is traveling on a snowy road or the like at the time of switching from drive to stop, there is a problem that slippage or the like is likely to occur due to large torque fluctuations and safety is impaired.

The present invention has been made in order to solve such a problem, and reduces the torque fluctuation at the time of switching the compressor from the driven state to the stopped state to prevent slipping on a snowy road or the like when the vehicle is running. It is an object of the present invention to provide a vehicle air-conditioning system for vehicles which is designed to be highly safe.

[0007]

A vehicle air conditioner according to the present invention for achieving the above object is a vehicle air conditioner provided with a main heating device, and a compressor for pumping a refrigerant, and this compressor. A condenser connected to the discharge side of the compressor, and a heat exchanger connected to the suction side of the compressor, the air passage flowing through the heat exchanger, and the air passage heated by the main heating device. Of a heat exchanger provided in series with the main heating device so that at least partially coincide with each other, an opening / closing valve provided in a path connecting the compressor and the condenser, and a bypass valve of the opening / closing valve bypassing the condenser. A bypass pipe connected to the path connecting the condenser and the heat exchanger from the inlet side, a decompression device provided in the bypass pipe, and a refrigerant flowing in the bypass pipe when the compressor is stopped Immediately before stop Characterized by comprising a compressor stop control means for stopping the compressor after reducing the suction pressure of the compressor to open the on-off valve.

[0008]

According to the vehicle air conditioner of the present invention, for example, during heating at the time of cold start of the internal combustion engine, for example, as shown in FIG. 2, the compression work performed by the compressor of the vehicle air conditioner becomes thermal work. The heat is dissipated by the heat exchanger through the pressure reducing device. Therefore, since the heat radiation amount of the evaporator of the vehicle air conditioner is added to the heat radiation amount of the hot water heater, the heat generation amount increases and the heating capacity increases. Further, in the internal combustion engine that gives work to the compressor, its exhaust heat is transferred to the hot water for cooling the internal combustion engine,
The amount of heat radiated from the heater core through which the cooling hot water flows increases. Therefore, rapid heating is possible and heating capacity is improved.

When it becomes unnecessary to continue the heating using the high temperature gas refrigerant in the refrigeration cycle, the refrigerant pumped from the compressor is allowed to flow to the condenser side for a predetermined time, and the operation of the compressor is continued for a predetermined time. Since this is maintained, the torque fluctuation of the compressor is reduced, and the influence of the torque exerted on the drive system by the internal combustion engine for traveling the vehicle is gently reduced. For this reason,
When the vehicle is traveling on a snowy road or the like, slipping is unlikely to occur and safety is high.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. First application of the present invention to a vehicle air conditioner for a vehicle
The refrigerant circuit of the embodiment is shown in FIG. Cooling water piping 2 communicating with the water jacket of an internal combustion engine 1 mounted on a vehicle
Communicates with the inside of the tube of the heater core 3a of the hot water heater 3, and the tube of the heater core 3a is connected to the cooling water return pipe 4
Communicates with the water jacket of the internal combustion engine 1.
The water jacket is provided with a water temperature sensor 102 for detecting the water temperature, and the cooling water pipe 2 is provided with an opening / closing valve 5.

On the other hand, the refrigerant circuit of the vehicle air conditioner 6 includes a compressor 10 driven by the internal combustion engine 1 and a condenser 1
1, receiver 12, first pressure reducing device 13, heat exchanger 1
4 and the accumulator 15 are connected in order by the pipe 16. Then, between the first on-off valve 18a provided between the compressor 10 and the condenser 11 and the compressor 10,
One end 20a of the bypass pipe 20 that bypasses the condenser 11 through which the air blown by the blower fan 35 can pass is connected, and the other end 20b of the bypass pipe 20 communicates with the pipe 16 between the first pressure reducing device 13 and the heat exchanger 14. To do. The bypass pipe 20 is provided with a second pressure reducing device 22. A second opening / closing valve 18b is provided between the second pressure reducing device 22 and one end 20a of the bypass pipe.

[0012] appropriate pressure gas refrigerant is controlled by the second pressure reducing device 22, 15 kg / cm ² or more on the high pressure side of the second pressure reducing device 22, 2-4 kg / cm ² in the low-pressure side
Is. This is because when the outside air temperature is low, the temperature on the low pressure side is also low, so that the pressure on the high pressure side is kept high in order to obtain sufficient heating capacity, and as shown in FIG. This is because the pressure on the high pressure side of the second decompression device 22 is 15 kg /
cm ² or more is desirable.

A check valve 24 is provided in the pipe 16 between the receiver 12 and the first pressure reducing device 13. Check valve 2
Reference numeral 4 prevents the refrigerant from flowing back into the condenser 11 and becoming insufficient. Further, the accumulator 15 collects the refrigerant when the refrigerant becomes excessive and prevents the liquid from returning to the compressor 10, so that the hot gas refrigerant always circulates in the refrigerant circuit.

A thermistor 103 for detecting the air temperature is provided near the air outlet of the heat exchanger 14, and the pressure of the refrigerant in the pipe is detected in the pipe between the compressor 10 and the one end 20a of the bypass pipe 20. The pressure sensor 104 is attached. The input device 101 is a device for inputting driving and stopping of cooling and driving and stopping of heating. Water temperature sensor 10
2, the thermistor 103, the pressure sensor 104, and the input device 1
The output of 01 is received by the control device 100, and the output of the control device 100 is the compressor 10, the first on-off valve 18a,
The second on-off valve 18b and the blower fans 28 and 35 are controlled.

Here, the thermistor 103 detects the air temperature after the heat exchanger 14 during cooling. Control device 100
Determines whether the heat exchanger 14 is frozen based on the air temperature detected by the thermistor 103. When it is determined that the heat exchanger 14 is frozen, the compressor 1
Stop 0. After that, when the air temperature detected by the thermistor 103 rises and there is no fear of freezing, the compressor 1
Restart 0 operation. The compressor 10 is not stopped during heating.

The pressure sensor 104 detects the refrigerant pressure in the refrigerant cycle. During cooling, the control device 100 determines that the pressure detected by the pressure sensor 104 is abnormal even when the pressure is above or below a predetermined pressure range in order to protect the equipment, and stops the compressor 10. After that, when the pressure detected by the pressure sensor 104 falls within a predetermined range, the operation of the compressor 10 is restarted. When heating
It is not judged to be abnormal even within the specified pressure range.

The water temperature sensor 102 detects the cooling water temperature of the internal combustion engine 1. Whether or not a radiator (not shown) through which the cooling water flows is radiating heat is determined by whether hot water is flowing through the radiator or whether hot water is flowing through a bypass pipe that bypasses the radiator and is not flowing through the radiator. When the control device 100 determines that the radiator state is heat dissipation, the compressor 10 is stopped. After that, when the cooling water temperature detected by the water temperature sensor 102 decreases and heat is no longer released, the operation of the compressor 10 is restarted. Water temperature sensor 10
The control by 2 is performed only during heating.

The heater core 3 which constitutes the main heating device
a and a heat exchanger 14 that functions as an auxiliary heating device during heating
Are arranged in series in the ventilation duct 26, and the blower fan 2
The air taken into the ventilation duct 26 by the air blower 8 is blown into the passenger compartment from a blow-out port (not shown) via the heat exchanger 14 and the heater core 3a. During cooling, the first opening / closing valve 18a is opened and the second opening / closing valve 18b is closed, so that the refrigerant from the compressor 10 flows only to the condenser 11 side, and the refrigerant from the compressor 10 is fed to the condenser 11, the receiver 12, and the receiver 11. The first pressure reducing device 13, the heat exchanger 14, the accumulator 15, and the compressor 10 circulate in this order. In the heat exchanger 14, the blower fan 2
The air sent from the heat exchanger 8 into the heat exchanger 14 is deprived of heat by the refrigerant, becomes cold air, flows from the ventilation duct 26 in the direction of the arrow in the drawing, passes through the heater core 3a, and is blown out into the vehicle interior.

During heating, the first on-off valve 18a is closed and the second on-off valve 18b is opened, so that the refrigerant from the compressor 10 flows only to the bypass pipe 20 side, and the refrigerant from the compressor 10 flows to the second side.
Decompression device 22, heat exchanger 14, accumulator 1
5, the compressor 10 is circulated in this order. The high-temperature and high-pressure refrigerant gas blown out by the compressor 10 is decompressed by the second decompression device 22 and changes into a high-temperature and low-pressure gas refrigerant.

When the high-temperature low-pressure hot gas refrigerant passing through the second pressure reducing device 22 is introduced into the heat exchanger 14, the air that has taken heat from the high temperature gas is heated, and the hot water on the downstream side in the direction of the arrow in the drawing is further heated. Heat is taken from the warm water in the heater core 3a of the heater 3 to further heat the air, and the heated warm air is blown into the vehicle compartment through a blow-out port (not shown). The change of the refrigerant is shown on the Mollier diagram as shown in FIG. That is, when the first on-off valve 18a is closed and the second on-off valve 18b is open, the high-temperature high-pressure gas refrigerant compressed by the compressor 10 changes from the low-pressure P _L to the high-pressure P _H. When passing through the decompression device 22 of No. 2, the gas pressure changes from high pressure P _H to low pressure P _H.
It goes down to _L , enters the heat exchanger 14, and then is introduced to the inlet side of the compressor 10 via the accumulator 15.

As shown in FIG. 3, the compression work by the compressor 10 is such that the pressure on the outlet side of the compressor 10 becomes a high pressure P _H ,
It is desirable that the high pressure P _H be 15 kg / cm ² or more. When the suction pressure of the compressor 10 is in the range of 1 to 5 kg / cm ² , the blowout pressure (high pressure P _H ) on the compressor outlet side is 15 kg / c.
This is because the compression power becomes larger when it is m ² or more.

According to this embodiment, since the compressor 10 is driven by the internal combustion engine 1, the load on the internal combustion engine 1 increases, the heat generated in the internal combustion engine is transferred to the cooling hot water, and the heat of this cooling hot water is transferred. The heater core 3a raises the temperature of the blown air, and the heating capacity of the heater core 3a also increases. Therefore, the air is heated by the high temperature and low pressure hot gas refrigerant in the heat exchanger 14,
The heated air further draws heat from the internal combustion engine cooling hot water by the heater core 3a and is heated to a higher temperature. Therefore, the heating capacity of the vehicle air conditioner 6 is considerably increased,
Increased heating capacity and rapid heating are possible.

When stopped, the on-off valves 18a and 18b are
During both cooling and heating, the bypass pipe 20 is switched to open on the heating side and stopped. The reason is that the condenser 11 and the receiver 12 are in a sealed state during heating, so that if a large amount of refrigerant exists in this portion, the cycle may run short of refrigerant during heating. When stopped, if the first opening / closing valve 18a and the second opening / closing valve 18b are switched to the heating side and the condenser 11 and the receiver 12 are sealed, the refrigerant does not flow into the condenser 11 and the receiver 12 from other portions. This is because the required refrigerant can be secured during heating.

Further, in this embodiment, when the hot gas cycle which is the auxiliary heating is stopped, the compressor is not switched off immediately. The reason for this is clear that the torque fluctuation is compared between the comparative example in which the compressor is immediately turned off when the request signal for stopping the hot gas cycle is input to the control device and the present example in which the compressor is not immediately turned off. Is.

For example, as shown in FIG. 4, in the comparative example, the torque sharply decreases immediately after the compressor is switched from ON to OFF. As a result, the torque fluctuation of the vehicle drive system becomes large, and if the vehicle is traveling on a snowy road at that time, the wheels are likely to slip with the road surface. On the other hand, in the present embodiment, the first opening / closing valve 18 is operated when the compressor off request signal is input to the control device.
When a is opened and the refrigerant pressure-fed from the compressor 10 is also made to flow to the condenser 11 side, the torque is gently reduced, and when the refrigerant pressure on the suction side of the compressor 10 becomes a predetermined value or less, the first opening / closing The valve 18a is closed. As a result, the compressor 1
When the refrigerant pressure on the suction side of 0 becomes a sufficiently low value, the compressor 10 is turned off, so there is no sudden change in torque,
The drive system is prevented from slipping and the drivability is not impaired.

The control during heating according to the present invention is as shown in the control flow of FIG. In step 201, it is determined whether the blower fans 28, 35 are on. When the blower fans 28, 35 are on, it is determined in step 202 whether the air conditioner switch is on. When the air conditioner switch is on, heating is performed in step 203. Determine if the switch is on. When the heating switch is on, it is determined in step 204 whether the refrigerant pressure is below a predetermined pressure. This is because the compressor 10 is overloaded when the refrigerant pressure is higher than the predetermined pressure,
This is to stop the operation of the compressor 10. When the refrigerant pressure is below the predetermined value, the routine proceeds to step 205, where it is determined whether the water temperature of the internal combustion engine is above or below the predetermined temperature. If the water temperature is equal to or higher than the predetermined temperature, the heating capacity is sufficiently high due to the heat exchange in the heater core 3a of the main heating device, so the operation of the auxiliary heating device is stopped. This is because it is not necessary to operate the auxiliary heating device if the water temperature exceeds the predetermined temperature. If the water temperature is equal to or lower than the predetermined temperature, it is determined in step 206 whether the temperature setting of the outdoor heating switch is the maximum temperature. This is because it is preferable to operate the auxiliary heating device at the time of setting the maximum temperature because the demand for increasing the heating capacity is particularly large, and it is desirable to stop the auxiliary heating device if the temperature setting is not maximum from the viewpoint of energy saving. . When the conditions in steps 201 to 206 are satisfied, the compressor 10 is turned on in step 207.

In other cases, the first opening / closing valve 18a is opened in step 209, and then it is determined in step 210 whether the refrigerant pressure has dropped below a predetermined value. If there is, the compressor 10 is turned off. At this time, the operation of the compressor 10 is continued while the refrigerant pressure exceeds the predetermined value. This is to suppress the torque fluctuation of the vehicle drive system by the sudden decrease of the load torque of the compressor 10 and prevent the wheel slip.

During cooling, when the cooling switch is turned on in step 208, normal cooling operation is performed.
Therefore, under the condition of the auxiliary heating, the pressure sensor 104
The auxiliary heating device can be operated even when the detected refrigerant pressure is low, and the auxiliary heating device can be operated even if the heat exchanger 14 is determined to be frozen. During heating control, after the operation of the compressor 10 is stopped, the operation of the compressor 10 is restarted when the abnormality of the refrigerant pressure and the cooling water temperature is resolved. However, when it is used only for improving the heating start-up performance, the compressor is It is not necessary to restart the operation of 10.

In steps 201 to 203, it is determined whether the hot gas heater is operating, and step 2
From 04 to 206, it is determined whether there is a request to stop the hot gas heater. When it is determined that there is a request to stop the hot gas heater, the process proceeds to step 209, and the first opening / closing valve 18a is opened. In this state, the on-off valves 18a, 1
Since both 8b are open, the refrigerant also moves to the condenser 11 side, and the discharge and suction pressures of the compressor 10 both decrease, so the torque gradually decreases as shown in FIG. Next, the routine proceeds to step 210, where it is determined by the refrigerant pressure on the compressor suction side that the torque has sufficiently decreased. If the refrigerant pressure is below a predetermined pressure, the routine proceeds to the next step, 211, where the compressor is turned off. . Such steps 209, 2
By adding the control of 10, the torque fluctuation when the compressor stops can be reduced, and the problem in safety can be solved.

In the above embodiment, the heat exchanger 14 is provided upstream of the hot water heater 3 with respect to the air flow, but it may be provided downstream of the hot water heater 3. Further, the check valve 24 may be an open / close valve, or may also be used as the first pressure reducing device 13. Further, instead of the thermistor 103, another temperature sensor such as a thermostat may be used. Instead of the thermistor signal, the surface temperature of the heat exchanger 14 may be detected. Further, the mounting position of the pressure sensor 104 may be provided in the high pressure portion of the bypass pipe 20 instead of the position of the first embodiment. In this case, a dedicated pressure sensor for heating can be used. Further, the stop of the compressor 10 may be directly used as a switch without depending on the control device 100. It is also possible to newly perform the water temperature cut without performing the low pressure cut and the frost cut of the air conditioner during heating and cooling.

The above embodiment is an example in which the present invention is applied to a car cooler of a vehicle air conditioner for a vehicle. However, except for the parts such as the condenser 11 and the receiver 12 used in the embodiment, which are used only for cooling, the hot Only the gas cycle may be used exclusively for auxiliary heating. Further, both the receiver 12 and the accumulator 15 of the above-mentioned embodiment are devices for adjusting the amount of refrigerant, but the receiver 12 and the accumulator 1 are
5, the amount of the refrigerant may be adjusted, or the receiver 12 and the accumulator 15 may be omitted if the amount of the charged refrigerant can be managed separately. Further, in the embodiment of the present invention, the heat source of the main heating device is the hot water for cooling the internal combustion engine, and the heat source of the auxiliary heating device is the refrigerant circulated in the refrigerant circuit (hot gas). The heat source is not limited to the cooling hot water of the internal combustion engine, and may be another heat source. The drive source of the compressor is the internal combustion engine, but a voltage source may be used instead. Furthermore, the on-off valve 18
Instead of a and 18b, other switching means such as a three-way valve arranged at the branch point of the bypass pipe may be used. Furthermore, when the stop request of the hot gas cycle is requested, the period in which the first on-off valve 18a is opened may be set to a fixed time.

[0032]

As described above, according to the vehicle air conditioner of the present invention, a simple heating device using the high-temperature and high-pressure gas refrigerant in the refrigerant circuit is constructed. Therefore, this heating device is used as the main heating device. In addition to the above, the heating capacity is improved, which has the effect of enabling rapid heating.

When the vehicle travels on a slippery road surface such as a snowy road, if the vehicle air conditioner of the present invention is driven, when a signal for stopping auxiliary heating is input to the control device, compression is performed. By continuing the operation of the machine for a while and flowing the refrigerant in the refrigerant circuit to the condenser side, the refrigerant flow to the bypass pipe for auxiliary heating is reduced and the torque is gently reduced. Therefore, the fluctuation of the torque transmitted to the drive system of the internal combustion engine is reduced, and the occurrence of slip and the like is prevented, so that there is an effect that the safety while the vehicle is traveling is enhanced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a refrigerant circuit of a vehicle air conditioner according to an embodiment of the present invention.

FIG. 2 is a partial Mollier diagram showing a refrigeration cycle according to an example of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the suction pressure and the compression power of the compressor used in the example of the present invention.

FIG. 4 is a comparative diagram comparing the torque change when the compressor is switched off between the example of the present invention and the comparative example.

FIG. 5 is a flowchart showing a control flow according to an embodiment of the present invention.

FIG. 6 is a circuit diagram showing a refrigerant circuit of a conventional vehicle air conditioner.

[Explanation of symbols]

 1 Internal Combustion Engine 3 Hot Water Heater (Main Heating Device) 10 Compressor (Refrigerant Compressor) 11 Condenser 13 First Pressure Reduction Device 14 Evaporator (Heat Exchanger) 18a First Open / Close Valve 18b Second Open / Close Valve 20 Bypass Pipe 22 Second decompression device

Claims (1)

[Claims] 1. A vehicle air conditioner including a main heating device, comprising a compressor for pumping a refrigerant, a condenser connected to a discharge side of the compressor, and a suction side of the compressor. A heat exchanger, which is provided in series with the main heating device such that an air flow passage flowing through the heat exchanger and an air flow passage heated by the main heating device at least partially coincide with each other. And an on-off valve provided in a path connecting the compressor and the condenser, and a bypass pipe bypassing the condenser and connected to a path connecting the condenser and the heat exchanger from the inlet side of the on-off valve. A decompression device provided in the bypass pipe, and when a refrigerant flows through the bypass pipe, when the compressor is stopped, the on-off valve is opened immediately before the compressor is stopped and the compressor after the suction pressure of the compressor is lowered is reduced. Stop Air conditioning system characterized by comprising a compressor stop control means.