JP2021079827A - Air conditioner for vehicle - Google Patents

Abstract

To provide an air conditioner for a vehicle which suppresses the generation of noise.SOLUTION: An air conditioner for a vehicle comprises a compressor, a condenser, an expansion valve, an evaporator, a refrigerant pipeline, and a control unit. The control unit comprises: an air conditioning control unit which performs control of the compressor, and a load amount acquisition unit which acquires a load amount of a refrigeration cycle device. The compressor can switch between two control methods of the on-off control in which the compression capacity at the driving is constant and the variable control in which the compression capacity at the driving can be varied. The air conditioning control unit executes a low noise mode for switching the control method of the compressor to the on-off control or the variable control on the basis of the load amount acquired by the load amount acquisition unit. Consequently, the air conditioner for the vehicle which suppresses the generation of noise can be obtained.SELECTED DRAWING: Figure 3

Description

The disclosure herein relates to vehicle air conditioners.

Patent Document 1 discloses a refrigeration cycle device that reduces the refrigerant discharge capacity of a compressor as compared with normal operation when it is in a low background noise state. As a result, the flow rate of the refrigerant circulating in the cycle is reduced and the sound of the refrigerant flowing is suppressed under low background noise conditions where unintended sounds tend to be offensive to the occupants. Further, the present invention discloses an electric compressor that controls the refrigerant discharge capacity by controlling the rotation speed of the electric motor. The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification.

Japanese Unexamined Patent Publication No. 2012-242000

In the structure of the prior art document, the refrigerant discharge capacity of the compressor is controlled to be low in order to suppress the sound generated by the flow of the refrigerant when the compressor is started. However, the compressor can make noises other than at startup. For example, when a gas-liquid two-phase state refrigerant flows through a refrigerant flow path in which a liquid-phase state refrigerant should flow, unintended vibration may occur and a refrigerant passing noise may be generated. This refrigerant passing noise is likely to occur at low outside temperatures when the amount of refrigerant discharged from the compressor is small. Further, when the amount of the gas phase refrigerant circulating in the refrigeration cycle apparatus is large, the suction pulsation sound of the compressor may be generated. This suction pulsation sound is likely to occur at high outside temperatures where the amount of refrigerant discharged from the compressor is large. If the occupant perceives the sound of passing refrigerant or the sound of inhalation pulsation as noise, the comfort in the passenger compartment may be impaired. Further improvements are required in vehicle air conditioners in the above aspects, or in other aspects not mentioned.

One object disclosed is to provide a vehicle air conditioner that suppresses the generation of noise.

The vehicle air conditioner disclosed here includes a compressor (31) that compresses the refrigerant circulating in the refrigeration cycle device (30), a condenser (35) that condenses the vapor phase refrigerant compressed by the compressor, and the like. An expansion valve (48) that expands the liquid-phase refrigerant condensed by the compressor, and an evaporator (48) that evaporates the liquid-phase refrigerant by exchanging heat between the liquid-phase refrigerant expanded by the expansion valve and the air provided in the passenger compartment. 39), a compressor pipe (40) that connects a compressor, a condenser, an expansion valve, and an evaporator to allow refrigerant to flow inside, and a control unit (50) that controls air conditioning operation. The compressor includes an air conditioner control unit (51) that controls the compressor and a load amount acquisition unit (52) that acquires the load amount of the refrigeration cycle device, and the compressor is on / off control in which the compression capacity at the time of driving is constant. It is possible to switch between two control methods, variable control that can change the compression capacity during driving, and the air conditioning control unit controls the compressor control method on and off based on the load amount acquired by the load amount acquisition unit. A low noise mode is executed to switch between the control and the variable control.

According to the disclosed vehicle air conditioner, the air conditioner control unit that executes the low noise mode that switches the control method of the compressor between on / off control and variable control based on the load amount acquired by the load amount acquisition unit. I have. Therefore, it is possible to properly use whether to control the compressor on / off or variably depending on the situation. Therefore, it is possible to suppress the generation of the suction pulsation sound that is likely to be generated when the compressor is on / off controlled and the refrigerant passing sound that is likely to be generated when the compressor is variably controlled. Therefore, it is possible to provide a vehicle air conditioner that suppresses the generation of noise.

The disclosed aspects herein employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses described in this section exemplify the correspondence with the parts of the embodiments described later, and are not intended to limit the technical scope. The objectives, features, and effects disclosed herein will be made clearer by reference to the subsequent detailed description and accompanying drawings.

It is a block diagram which shows the schematic structure of the air conditioner for a vehicle. It is a block diagram concerning the control of the air conditioner for a vehicle. It is a flowchart about control of the air conditioner for a vehicle. It is a flowchart about control of the vehicle air conditioner in 2nd Embodiment.

A plurality of embodiments will be described with reference to the drawings. In a plurality of embodiments, functionally and / or structurally corresponding parts and / or related parts may be designated with the same reference code or reference codes having a hundreds or more different digits. References can be made to the description of other embodiments for the corresponding and / or associated parts.

The first embodiment vehicle air conditioner 1 is an air conditioner mounted on a vehicle. The vehicle is, for example, an automobile equipped with a gasoline-powered engine. However, as the vehicle, an electric vehicle equipped with a traveling motor, a hybrid vehicle equipped with both an engine and a traveling motor, and the like can also be adopted. The vehicle air conditioner 1 is a device that adjusts the temperature and humidity of the taken-in air and blows it out into the vehicle interior. In other words, the vehicle air conditioner 1 is a device that performs air conditioning operations such as heating operation, cooling operation, and dehumidifying operation in the vehicle interior.

In FIG. 1, the vehicle air conditioner 1 includes a blower unit 10 for blowing air and an air conditioner unit 20 for adjusting the temperature of the blown air. The blower unit 10 includes a blower case 11 and a blower 15. The blower case 11 includes two inlets, an inside air inlet 14a and an outside air inlet 14b. Inside the blower case 11, an inside / outside air switching door 12 for switching the opening / closing of the inside air introduction port 14a and the outside air introduction port 14b is provided. The inside / outside air switching door 12 can execute the inside air circulation mode, which is a mode in which the conditioned air circulates in the room. The inside / outside air switching door 12 can execute the outside air introduction mode, which is a mode in which the air conditioning air is introduced from the outside.

The blower 15 is provided inside the blower case 11. The blower 15 is an electric blower whose rotation speed can be controlled by using an electric motor. The blower 15 is a device for sending the air taken in from the introduction port from the blower unit 10 toward the air conditioning unit 20. The blower 15 is, for example, a centrifugal blower, and a sirocco fan or a turbo fan can be adopted.

The air conditioning unit 20 includes an air conditioning case 21, a heater device 32, and an evaporator 39. The heater device 32 is a device for heating air in the air conditioning operation. The heater device 32 is an electric heater that can not only control the on / off of the output but also electrically control the magnitude of the output. However, the heater device 32 may be composed of a heater core in which high-temperature engine cooling water circulates inside.

The evaporator 39 is a device for evaporating the liquid phase refrigerant into the vapor phase refrigerant. The evaporator 39 is a heat exchanger that takes heat from the surroundings when evaporating the refrigerant. In other words, the evaporator 39 is a cooling heat exchanger for cooling the air in the air conditioning operation. Inside the air conditioning case 21, the evaporator 39 is provided located upstream of the air flow from the heater device 32.

The air conditioning case 21 includes three openings, a defroster opening 24a, a face opening 24b, and a foot opening 24c. The defroster opening 24a is an opening through which air conditioning air flows toward the front window. The face opening 24b is an opening through which air-conditioning air flows toward the upper body including the occupant's face. The foot opening 24c is an opening through which air-conditioning air flows toward the lower body including the feet of the occupant.

An air mix door 25 is provided inside the air conditioning case 21. The air mix door 25 is a door that adjusts the ratio of air that has passed through the evaporator 39 to the heater device 32. Inside the air conditioning case 21, a defroster door 22a, a face door 22b, and a foot door 22c are provided. The defroster door 22a is a door that controls the opening and closing of the defroster opening 24a. The face door 22b is a door that controls the opening and closing of the face opening 24b. The foot door 22c is a door that controls the opening and closing of the foot opening 24c.

The refrigeration cycle device 30 is a cooling device that causes the evaporator 39 to function as a heat source for cooling. The refrigeration cycle device 30 includes a compressor 31, a condenser 35, and a refrigerant pipe 40 in addition to the evaporator 39. The compressor 31 is a device that compresses the gas phase refrigerant into a high temperature and high pressure state. The compressor 31 is a variable capacitance compressor capable of changing the compression capacitance at the time of driving. The compressor 31 is controlled into two states, a stopped state and a driven state. In the driving state of the compressor 31, the amount of the refrigerant circulating in the refrigeration cycle device 30 can be adjusted by changing the compression capacity of the compressor 31. That is, by increasing the compression capacity of the compressor 31, the amount of the refrigerant circulating in the refrigeration cycle device 30 can be increased.

The compressor 31 is a compressor capable of switching between on / off control in which the compression capacity is constant and only on / off of driving is controlled, and variable control in which the compression capacity is changed according to the required air conditioning capacity. In the on / off control, the drive is maintained until the temperature inside the vehicle reaches the target temperature, and the drive is stopped when the target temperature is reached. In the on / off control, the refrigerant discharge capacity when the compressor 31 is driven is always in a high state.

In the variable control, when the temperature difference between the temperature in the vehicle interior and the target temperature set by the occupant is large, the capacity of the refrigeration cycle device 30 is increased by driving the compressor 31 with a large compression capacity. As a result, the temperature inside the vehicle can be quickly brought closer to the target temperature. At this time, the output of the blower 15 and the outdoor blower 36 is also increased to increase the air conditioning capacity of the entire vehicle air conditioner 1. On the other hand, when the temperature difference between the temperature inside the vehicle interior and the target temperature set by the occupants is small, the capacity of the refrigeration cycle device 30 is lowered by driving the compressor 31 with a small compression capacity. As a result, the energy consumed when driving the compressor 31 is reduced as compared with the case where the compression capacity is high. In the variable control, the compressor 31 is driven while appropriately changing the refrigerant discharge capacity, so that the air conditioning operation is performed in a longer driving time than the on / off control.

The on / off control is always driven by a high refrigerant discharge capacity. Therefore, the on / off control can easily reach the target temperature in a shorter time than the variable control. The variable control is driven by properly using a state in which the refrigerant discharge capacity is high and a state in which the refrigerant discharge capacity is low. Therefore, in the variable control, the number of times the compressor 31 is turned off is smaller than that in the on / off control. In other words, the variable control tends to reduce the number of times the compressor 31 is activated during a series of air conditioning operations as compared with the on / off control.

The condenser 35 is a heat exchanger provided outside the air conditioning case 21 to exchange heat with the outdoor air. In the cooling operation, the condenser 35 is a heat exchanger that condenses the gas phase refrigerant into the liquid phase refrigerant by releasing heat to the outside air and lowering the energy of the refrigerant. An outdoor blower 36 is provided facing the condenser 35. The outdoor blower 36 is a device for promoting heat exchange between the outside air and the refrigerant by supplying the outside air before heat exchange to the periphery of the condenser 35.

The refrigerant pipe 40 connects the compressor 31, the condenser 35, and the evaporator 39 to provide a refrigerant flow path through which the refrigerant circulates. The refrigerant pipe 40 includes an expansion valve 48 at a portion connecting the condenser 35 and the evaporator 39. The expansion valve 48 is a device for expanding the liquid phase refrigerant flowing into the evaporator 39 to facilitate evaporation in the evaporator 39. The expansion valve 48 is also called a pressure reducing device that reduces the pressure of the refrigerant. The expansion valve 48 may be provided integrally with the refrigerant inlet portion of the evaporator 39.

An evaporator sensor 91c for measuring the temperature of the evaporator 39 is provided on the outer surface of the evaporator 39. In the refrigerant pipe 40, a pressure sensor 91d for measuring the pressure of the refrigerant is provided between the condenser 35 and the expansion valve 48.

In FIG. 2, the control unit 50 is connected to the air conditioning sensor 91, the air conditioning switch 92, and the vehicle speed sensor 80. The air conditioning sensor 91 includes an outside air temperature sensor 91a, an inside air temperature sensor 91b, an evaporator sensor 91c, and a pressure sensor 91d. The outside air temperature sensor 91a is a sensor that measures the temperature outside the vehicle. The inside air temperature sensor 91b is a sensor that measures the temperature inside the vehicle. The evaporator sensor 91c is a temperature sensor that measures the surface temperature of the evaporator 39. The pressure sensor 91d is a sensor that measures the pressure of the refrigerant before it passes through the condenser 35 and flows into the expansion valve 48. The control unit 50 acquires various information used for the air conditioning operation from the air conditioning sensor 91.

The air conditioning switch 92 is a switch operated by an occupant. The air-conditioning switch 92 includes a switch for switching on / off of the air-conditioning operation, a switch for switching the set temperature, a switch for switching between the inside air circulation mode and the outside air introduction mode, and the like. The air-conditioning switch 92 includes a switch for selecting which mode the air-conditioning operation is to be performed among a plurality of blow-out modes having different blow-out ports such as the face mode. However, when the air-conditioning operation is performed in the auto mode, the switching is automatically performed instead of switching the blowing mode or the like by the operation by the occupant. The control unit 50 performs the air conditioning operation based on the air conditioning setting set by the occupant using the air conditioning switch 92.

The vehicle speed sensor 80 is a speed sensor that measures the running speed of the current vehicle. The vehicle speed sensor 80 measures the vehicle speed by detecting the number of rotations of the tire. However, the method of detecting the vehicle speed with the vehicle speed sensor 80 is not limited to the method of detecting the number of rotations of the tire. The control unit 50 changes the air conditioning control based on the vehicle speed information measured by the vehicle speed sensor 80.

The control unit 50 is connected to the inside / outside air switching door 12, the defroster door 22a, the face door 22b, the foot door 22c, and the air mix door 25. The control unit 50 changes the opening degree by controlling the drive of the servomotors of the doors 12, 22a, 22b, 22c, and 25. As a result, switching between the inside air circulation mode and the outside air introduction mode, temperature control of the air conditioner air, change control of the blowout position of the air conditioner air, and the like are performed.

The control unit 50 is connected to the blower 15, the compressor 31, the heater device 32, and the outdoor blower 36. The control unit 50 controls the output of the blower 15 to adjust the wind speed of the air conditioner air. The control unit 50 controls the presence / absence of driving of the compressor 31 and the compression capacity to adjust the amount of the refrigerant circulating in the refrigeration cycle device 30. The control unit 50 controls the output of the heater device 32 to adjust the heating amount of the air conditioning air. However, when the heater device 32 is composed of a heater core through which high-temperature engine cooling water heated by the heat of the engine flows, the heater device 32 does not have to be the control target. In this case, the high temperature engine cooling water continues to circulate in the heater device 32. The control unit 50 controls the output of the outdoor blower 36 to adjust the amount of heat exchange between the outside air and the refrigerant flowing through the condenser 35.

The control unit 50 includes an air conditioning control unit 51, a load amount acquisition unit 52, and a background noise information acquisition unit 53. The air conditioning control unit 51 controls the device used for the air conditioning operation. The air conditioning control unit 51 controls, for example, the drive of the compressor 31 to control the temperature of the air conditioning air. The air conditioning control unit 51 controls, for example, the drive of the blower 15 to control the air volume of the air conditioning air.

The load amount acquisition unit 52 acquires the load amount of the refrigeration cycle device 30. The greater the cooling capacity required by the refrigeration cycle device 30, the greater the load. Further, the larger the load amount, the larger the amount of refrigerant discharged from the compressor 31 is controlled. Therefore, the load amount corresponds to the target flow rate of the refrigerant circulated in the refrigeration cycle device 30. For example, when the cooling operation is started in a state where the outside air temperature is high, the load amount tends to increase. For example, the load tends to decrease during the cooling operation when the outside air temperature is close to the target temperature.

The background noise information acquisition unit 53 acquires background noise information which is information indicating the magnitude of background noise which is a sound other than the sound emitted by the compressor 31. More specifically, it can be estimated that the faster the vehicle speed measured by the vehicle speed sensor 80, the greater the background noise. On the other hand, it can be estimated that the background noise is small when the vehicle is stopped and the vehicle speed measured by the vehicle speed sensor 80 is zero. In this way, the background noise information acquisition unit 53 estimates and acquires the magnitude of background noise from the vehicle speed information measured by the vehicle speed sensor 80.

The background noise estimation method of the background noise information acquisition unit 53 is not limited to the vehicle speed. For example, a rain sensor may be provided, and the magnitude of background noise may be estimated and acquired from the weather information acquired by the rain sensor. More specifically, when it is detected that it is raining, it can be estimated that the background noise is large because of the influence of the rain sound. On the other hand, when it is not raining, it can be estimated that the background noise is small because it is not affected by the rain noise. Alternatively, the magnitude of background noise may be estimated and acquired from the presence or absence of sound output by the audio device. More specifically, when an audio device outputs sound such as music or radio, it can be estimated that the background noise is large. On the other hand, when the audio device does not output sound, it can be estimated that the background noise is small. Further, the sound pressure level of background noise may be acquired by using a microphone.

When the amount of refrigerant circulating in the refrigerating cycle device 30 is small, a refrigerant passing noise may be generated. Further, when the super heat in the refrigeration cycle device 30 is high, the suction pulsation sound of the compressor 31 may be generated. The mechanism of generating the refrigerant passing sound and the mechanism of generating the inhalation pulsating sound will be described below.

First, the mechanism of generating the refrigerant passing noise will be described. In the refrigeration cycle device 30 shown in FIG. 1, the smaller the temperature difference between the target temperature and the actual temperature in the vehicle interior, the easier it is for the compressor 31 to be controlled to a lower compression capacity during variable control. In other words, the compressor 31 is likely to be driven in a state where the refrigerant discharge capacity is low. This can occur in a cooling operation in a low outside air temperature situation, a dehumidifying operation during a heating operation, and the like.

Further, in the inside air circulation mode, if the temperature is close to the target temperature due to sufficient cooling of the vehicle interior, it is difficult for the refrigerant flowing through the evaporator 39 to obtain the heat required for evaporation from the air inside the vehicle. Become. On the other hand, in the outside air introduction mode, when the outside air has a temperature close to the target temperature, it becomes difficult for the refrigerant flowing through the evaporator 39 to obtain the heat required for evaporation from the air in the vehicle interior. When the refrigerant flowing through the evaporator 39 cannot be completely evaporated and a part of the refrigerant is in a liquid phase state, the liquid phase refrigerant is inside the evaporator 39 or the low pressure pipe on the suction side of the compressor 31 in the refrigerant pipe 40. Is easy to collect. That is, in the refrigerant existing in the refrigeration cycle apparatus 30, the proportion of the refrigerant present in the gas phase decreases, and the proportion of the refrigerant present in the liquid phase increases.

In the refrigeration cycle apparatus 30, the compression capacity of the compressor 31 is small and the proportion of the refrigerant in the gas phase is reduced, so that the refrigerant discharge capacity of the compressor 31 that compresses the gas phase refrigerant becomes very low. Therefore, the amount of refrigerant discharged from the compressor 31 may be smaller than the amount of refrigerant passing through the expansion valve 48. In such a state, a part of the gas-phase refrigerant passes through the condenser 35 before being condensed by the condenser 35, and flows into the expansion valve 48 in a gas-liquid two-phase state. The gas-liquid two-phase refrigerant forcibly flows through the expansion valve 48 through which the liquid-phase refrigerant should flow, so that vibration is generated when the refrigerant passes through. The vibration generated at this time is transmitted from the expansion valve 48 to the evaporator 39 to vibrate the evaporator 39. When the evaporator 39 vibrates, a radiated sound radiated from the evaporator 39 into the air conditioning case 21 is generated. Such a sound generated by the passage of the refrigerant may be referred to as a refrigerant passage sound below. The gas-phase refrigerant in the gas-liquid two-phase state refrigerant that causes the refrigerant passing noise is sometimes called flash gas.

The refrigerant passing sound generated by the evaporator 39 reverberates from the inside of the air conditioning case 21 to the openings 24a, 24b, and 24c. Here, the face opening 24b is provided closer to the occupant's face than the defroster opening 24a and the foot opening 24c. Therefore, when the refrigerant passing sound is transmitted to the vehicle interior through the face opening 24b, the occupant can easily perceive the refrigerant passing sound. In other words, the comfort in the passenger compartment is easily impaired by the sound of passing refrigerant.

Next, the mechanism by which the inhaled pulsating sound is generated will be described. In the refrigeration cycle apparatus 30 shown in FIG. 1, the higher the outside air temperature, the more easily the refrigerant in the refrigeration cycle apparatus 30 exists in the gas phase. Further, in the cooling operation, the higher the outside air temperature, the higher the refrigerant discharge capacity of the compressor 31 required to control the inside air temperature to approach the target temperature. This can occur at the start of cooling operation in a situation where the outside temperature is high, such as in summer.

In the refrigeration cycle apparatus 30, the compressor 31 has a large compression capacity and the proportion of the gas phase refrigerant increases, so that the refrigerant discharge capacity of the compressor 31 that compresses the gas phase refrigerant is required to be extremely high. To. Therefore, the amount of the refrigerant sucked into the compressor 31 and the amount of the refrigerant discharged are increased. Therefore, a large pulsation may occur in the flow of the refrigerant in the process from suction to discharge.

The pulsation generated by the compressor 31 is transmitted to the evaporator 39 to vibrate the evaporator 39. When the evaporator 39 vibrates, a radiated sound radiated from the evaporator 39 into the air conditioning case 21 is generated. As described above, the sound generated due to the pulsation due to the suction of the refrigerant may be referred to as the suction pulsation sound below.

The suction pulsating sound generated by the evaporator 39 reverberates from the inside of the air conditioning case 21 to the openings 24a, 24b, and 24c. Here, the face opening 24b is provided closer to the occupant's face than the defroster opening 24a and the foot opening 24c. Therefore, when the inhalation pulsation sound is transmitted to the vehicle interior through the face opening 24b, the occupant can easily perceive the inhalation pulsation sound. In other words, the comfort of the passenger compartment is easily impaired by the inhalation pulsation sound.

The air-conditioning operation of the vehicle air-conditioning device 1 will be described below with an example of performing a cooling operation. In FIG. 3, when the cooling operation of the vehicle air conditioner 1 is started, such as when the air conditioner switch 92 is turned on by the occupant, background noise information is acquired in step S101. The background noise information is, for example, vehicle speed information. The vehicle speed information is the current traveling speed of the vehicle measured using the vehicle speed sensor 80. When the vehicle is stopped, the vehicle speed becomes zero. Here, the acquisition of vehicle speed information is not limited to the case where the vehicle speed sensor 80 is used. For example, the vehicle speed calculated from the amount of change in the absolute position based on a position information sensor such as GPS (Global Positioning Systems) may be acquired. Alternatively, the vehicle may be provided with a camera that functions as a peripheral monitoring device, and the vehicle speed calculated from the amount of change in the relative position acquired by the camera may be acquired. After acquiring the background noise information, the process proceeds to step S102.

In step S102, it is determined whether or not the background noise is equal to or greater than the threshold value. When the vehicle speed information is used as the background noise information, it is determined whether or not the vehicle speed is equal to or higher than the predetermined speed. Here, the predetermined speed is a speed at which the magnitude of the background noise generated by the traveling of the vehicle is assumed to be larger than the refrigerant passing sound and the suction pulsation sound. The predetermined speed is, for example, 20 km / h. If the vehicle speed is equal to or higher than the predetermined speed, it is determined that the background noise generated by the traveling of the vehicle is equal to or higher than the threshold value, and the process proceeds to step S117. On the other hand, if the vehicle speed is less than the predetermined speed, it is determined that the background noise generated by the traveling of the vehicle is less than the threshold value, and the process proceeds to step S111. The state where the vehicle speed indicating the state in which the vehicle is stopped is zero is included when the vehicle speed is less than a predetermined speed.

When weather information is used as background noise information, it is determined whether or not the weather is rainy. In this case, if it is rainy, it can be determined that the background noise is equal to or higher than the threshold value, and if it is not rainy, it can be determined that the background noise is less than the threshold value. When the output information of the audio device is used as the background noise information, it is determined whether or not the volume of the audio device is large. Further, it may be determined whether or not the background noise is equal to or more than the threshold value by combining a plurality of background noise information. Further, the occupant may input a threshold value as a criterion for determining the magnitude of the background noise and whether or not the background noise is loud. In this case, the occupant can set the background noise threshold high so that the background noise is always less than the threshold value.

In step S111, the load amount is acquired. The load amount is the magnitude of the load applied to the compressor 31 when the cooling operation is performed to a target temperature. The load amount can be estimated from the physical quantity that fluctuates depending on the conditions such as the outside air temperature and the temperature difference between the target temperature and the inside air temperature. The load amount increases as the cooling capacity required for the cooling operation increases. The load amount can be estimated from the outside air temperature measured by the outside air temperature sensor 91a. In this case, it can be judged that the higher the outside air temperature, the higher the cooling capacity is required, and the larger the load is. However, the method of acquiring the load amount is not limited to the above-mentioned method.

Another example of the load amount acquisition method is a method of acquiring the load amount from the temperature difference between the internal air temperature and the target temperature measured by the internal air temperature sensor 91b. In this case, it can be judged that the larger the temperature difference between the internal air temperature and the target temperature, the higher the cooling capacity is required, and the larger the load amount is.

Another example of the load amount acquisition method is a method of acquiring the load amount from the current value of the control valve used for the capacity control of the compressor 31. In this case, it can be determined that the larger the current value of the control valve, the larger the opening degree of the control valve and the larger the load amount.

Another example of the load amount acquisition method is a method of acquiring the load amount from the temperature measured by the evaporator sensor 91c. In this case, it can be determined that the higher the temperature of the evaporator 39, the more refrigerant needs to flow through the evaporator 39 to lower the temperature of the evaporator 39. In other words, it can be determined that the higher the temperature of the evaporator 39, the larger the load amount. Instead of the evaporator sensor 91c, a sensor for measuring the temperature of the outlet of the evaporator 39 may be provided to estimate the temperature of the evaporator 39.

Another example of the load amount acquisition method is a method of acquiring the load amount from the refrigerant pressure measured by the pressure sensor 91d. In this case, it can be determined that the higher the pressure, the larger the amount of refrigerant flowing into the evaporator 39, and the larger the load amount. The load amount may be acquired by combining the plurality of load amount acquisition methods described above. By combining multiple load amount acquisition methods, it is easy to acquire the load amount correctly. After acquiring the load amount, the process proceeds to step S112.

In step S112, it is determined whether or not the load amount is less than the high load amount. Here, the high load amount is a load amount in a state where the discharge capacity required by the compressor 31 is high. When the load amount is obtained from the outside air temperature, the high load amount is, for example, 25 ° C. If the load amount is less than the high load amount, the process proceeds to step S113. On the other hand, if the load amount is greater than or equal to the high load amount, it is determined that the suction pulsating sound caused by the compressor 31 may be generated, and the process proceeds to step S116.

In step S116, variable control of the compressor 31 is executed. If the compressor 31 has not been started yet, it will be started by variable control and driven by variable control. If the compressor 31 is started, it will be driven by variable control. As a result, the suction pulsation sound of the compressor 31 can be suppressed by appropriately controlling the amount of the refrigerant to be sucked by gradually increasing the compression capacity when the compressor 31 is started. Further, the time during which the compressor 31 is driven can be secured longer than when the on / off control is executed. Therefore, it is possible to prevent the super heat of the refrigerant from becoming excessively high and suppress the intake pulsation sound. Further, the number of times the compressor 31 is activated in the series of air conditioning control can be reduced.

When the outside air temperature is high, even after the inside air temperature drops to the target temperature and the cooling operation is no longer necessary, the inside air temperature tends to rise again to reach the temperature at which the cooling operation is required. When the on / off control is executed in such a situation, the compressor 31 is likely to be repeatedly driven and stopped within a short period of time, and the frequency of inhalation pulsation sound at the time of activation is likely to increase. On the other hand, when the variable control is executed, the state in which the compressor 31 is driven with a low discharge capacity is likely to be maintained even after the internal air temperature drops to the target temperature. Therefore, the number of times the compressor 31 is activated can be reduced, and the frequency of inhalation pulsation sound at the time of activation can be easily reduced. After executing the variable control, the variable control is maintained and the process proceeds to step S131.

In step S113, it is determined whether or not the load amount is less than the low load amount. Here, the low load amount is a load amount in a state where the discharge capacity required by the compressor 31 is low. The low load amount is set to at least a load amount equal to or less than the high load amount. When the load amount is obtained from the outside air temperature, the low load amount is, for example, 10 ° C. If the load amount is less than the low load amount, it is determined that the refrigerant passing noise may be generated by driving the compressor 31, and the process proceeds to step S115. On the other hand, when the load amount is the low load amount or more, it is determined that both the suction pulsation sound and the refrigerant passing sound are unlikely to be generated, and the process proceeds to step S117.

In step S115, on / off control of the compressor 31 is executed. If the compressor 31 has not been started yet, it will be started by on / off control and driven by on / off control. If the compressor 31 is started, it will be driven by on / off control. As a result, it is easy to secure a large amount of the gas phase refrigerant circulating in the refrigeration cycle device 30 as compared with the case where the variable control is executed. After executing the on / off control in which the refrigerant passing sound is generated, the on / off control is maintained and the process proceeds to step S131.

In step S117, an arbitrary control method of the compressor 31 is executed. In other words, the compressor 31 is executed by either on / off control or variable control, whichever is preferred. After the compressor 31 is driven by an arbitrary control method, the control method is maintained and the process proceeds to step S131.

In step S131, it is determined whether or not there is an air conditioning request. When the air-conditioning switch 92 is turned off by the occupant, there is no air-conditioning request. On the other hand, when the air conditioning switch 92 is kept on by the occupant, the state in which the air conditioning is requested is maintained. If there is no air conditioning request, the drive of the compressor 31 is stopped to end the air conditioning operation. On the other hand, when there is an air conditioning request, the process returns to step S101 and repeats a series of controls. As a result, the control method of the compressor 31 can be appropriately selected and executed according to the change in the surrounding environment and the progress of the air conditioning operation.

The control content from step S111 to step S131 corresponds to the control content of the low noise mode. In other words, if it is determined in step S102 that the background noise is below the threshold value, the low noise mode is executed, and if it is determined in step S102 that the background noise is above the threshold value, the normal mode is executed. There is. Here, the normal mode is a mode in which no special control is performed for the purpose of reducing the sound generated by the air conditioning operation.

According to the above-described embodiment, the air conditioning control unit 51 executes a low noise mode for switching whether the control method of the compressor 31 is on / off control or variable control based on the load amount acquired by the load amount acquisition unit 52. To do. Therefore, the on / off control and the variable control of the compressor 31 can be properly used depending on the situation. Therefore, the generation of sounds such as the refrigerant passing sound and the suction pulsating sound can be suppressed by controlling the compressor 31. Therefore, it is possible to provide the vehicle air conditioner 1 that suppresses the generation of noise.

By switching between on / off control and variable control, it is possible to suppress refrigerant passing noise and inhalation pulsation noise. Therefore, it is easier to reduce the weight of the vehicle air conditioner 1 as compared with the case where noise countermeasures using separate parts such as attaching a vibration damping member to the evaporator 39 for the purpose of absorbing vibration. However, noise countermeasures by control and noise countermeasures using separate parts may be used together.

The air conditioning control unit 51 controls the compressor 31 by variable control when the load amount is a high load amount or more. Therefore, it is possible to secure a longer driving time of the compressor 31 as compared with the case where the compressor 31 is controlled by on / off control. Therefore, it is easy to reduce the number of activations of the compressor 31 in a situation where the load amount is large and the temperature change of the internal air temperature tends to be large. Therefore, the influence of the inhaled pulsating sound at the time of starting the compressor 31 can be reduced.

The air conditioning control unit 51 controls the compressor 31 by on / off control when the load amount is less than the low load amount. Therefore, the state in which the compressor 31 has a high refrigerant discharge capacity is maintained. Therefore, it is possible to secure a large circulation amount of the gas phase refrigerant in the refrigeration cycle device 30 and suppress the generation of the refrigerant passing noise.

The load amount acquisition unit 52 estimates that the higher the outside air temperature acquired by the outside air temperature sensor 91a, the larger the load amount. Therefore, the load amount can be estimated and acquired even in a state where the refrigerant is not flowing, such as a state before starting the compressor 31.

The load amount acquisition unit 52 estimates that the larger the opening degree of the control valve used for the capacity control of the compressor 31, the larger the load amount. Therefore, the load amount can be estimated according to the actual refrigerant flow rate. Therefore, it is easy to estimate the load amount correctly.

The air conditioning control unit 51 executes the low noise mode when the background noise acquired by the background noise information acquisition unit 53 is less than the threshold value, and does not execute the low noise mode when the background noise is equal to or more than the threshold value. .. Therefore, in a state where the refrigerant passing sound and the suction pulsating sound are hard to be perceived by the occupants, the control method of the compressor 31 can be controlled without any limitation for the purpose of reducing noise. Therefore, highly comfortable air-conditioned operation can be performed by giving priority to factors other than low noise.

The background noise information acquisition unit 53 estimates that the faster the vehicle speed acquired by the vehicle speed sensor 80, the greater the background noise. Therefore, the magnitude of background noise can be estimated by using the vehicle speed sensor 80, which is often installed as standard in the vehicle. Therefore, it is possible to provide a vehicle air conditioner 1 in which the refrigerant passing sound and the suction pulsation sound are reduced with a simple configuration by effectively utilizing the parts conventionally mounted on the vehicle.

In step S112, it may be determined whether or not the load is high by using another physical quantity instead of the outside air temperature. For example, it is possible to determine whether or not the load is high from the temperature difference between the internal air temperature and the target temperature. Alternatively, it can be determined from the opening degree of the control valve of the compressor 31 whether or not the load is high. Alternatively, it can be determined from the temperature of the evaporator 39 measured by the evaporator sensor 91c whether or not the load is high. Alternatively, it can be determined from the refrigerant pressure measured by the pressure sensor 91d whether or not the load is high. Further, a plurality of physical quantities whose load can be estimated may be combined to determine whether or not the load is high from a plurality of pieces of information. According to this, it is possible to accurately determine whether or not the load is high and take measures against the inhaled pulsating sound.

In step S113, as in step S112, it may be determined whether or not the load is low by using another physical quantity instead of the outside air temperature. For example, it can be determined whether or not the load is low from the temperature difference between the internal air temperature and the target temperature. Alternatively, it can be determined from the opening degree of the control valve of the compressor 31 whether or not the load is low. Alternatively, it can be determined from the temperature of the evaporator 39 measured by the evaporator sensor 91c whether or not the load is low. Alternatively, it can be determined from the refrigerant pressure measured by the pressure sensor 91d whether or not the load is low. Further, a plurality of physical quantities whose load can be estimated may be combined to determine whether or not the load is low from a plurality of pieces of information. According to this, it is possible to accurately determine whether or not the load is low and take measures against the refrigerant passing noise.

The high load amount and the low load amount may be set to the same flow rate. In this case, if the load amount is equal to or more than the threshold value, variable control is executed, and if it is less than the threshold value, on / off control is executed. According to this, it is possible to determine whether to execute the on / off control or the variable control with a single determination.

Second Embodiment This embodiment is a modification based on the preceding embodiment. In this embodiment, the compressor 31 is started based on the pre-start load amount, and the compressor 31 is driven based on the post-start load amount.

The air-conditioning operation of the vehicle air-conditioning device 1 will be described below with an example of performing a cooling operation. In FIG. 4, when the cooling operation of the vehicle air conditioner 1 is started by the occupant turning on the air conditioner switch 92 or the like, it is determined in step S201 whether or not the compressor 31 is in the state before starting. To do. The state before startup is a state in which the compressor 31 is stopped. On the other hand, the state after startup is a state in which the compressor 31 is being driven. When starting the cooling operation, the compressor 31 is always in the state before starting. If the compressor 31 has not been started, the process proceeds to step S211. On the other hand, if the compressor 31 is not started, the process proceeds to step S221.

In step S211 to acquire the pre-start load amount. The pre-start load amount is a kind of load amount, and is a load amount in the compressor 31 before start-up. Like the load amount, the pre-start load amount can be estimated from the outside air temperature and the like. After acquiring the pre-start load amount, the process proceeds to step S212.

In step S212, it is determined whether or not the pre-start load amount is equal to or higher than the high load amount. The high load amount is a load amount in which a large inhalation pulsation sound is not generated even if the compressor 31 is controlled on and off. When the pre-start load is obtained from the outside air temperature, the high load is, for example, 25 ° C. If the pre-start load amount is greater than or equal to the high load amount, it is determined that inhalation pulsation sound is likely to occur, and the process proceeds to step S215. On the other hand, when the preload amount before activation is less than the high load amount, it is determined that the inhalation pulsation sound is unlikely to occur, and the process proceeds to step S216.

In step S215, variable control is executed. Since the compressor 31 is in the state before starting, the compressor 31 is started by variable control. As a result, the suction pulsation sound of the compressor 31 can be suppressed by appropriately controlling the amount of the refrigerant to be sucked by, for example, gradually increasing the compression capacity of the compressor 31. After starting the compressor 31 with variable control, the process proceeds to step S221.

In step S216, on / off control is executed. Since the compressor 31 is in a state before starting, the compressor 31 is started by on / off control. As a result, a large amount of refrigerant can be sucked in and compressed at one time. Therefore, the refrigerant flow rate can be increased more quickly than when the compressor 31 is started while gradually increasing the compression capacity by variable control. After starting the compressor 31 with on / off control, the process proceeds to step S221.

In step S221, the load amount after startup is acquired. The post-startup load amount is a kind of load amount, and is a load amount in the compressor 31 after start-up. Like the load amount, the load amount after startup can be estimated from the outside air temperature and the like. After acquiring the load amount after startup, the process proceeds to step S222.

In step S222, it is determined whether or not the load amount after startup is less than the low load amount. The low load amount is a load amount that does not generate a large refrigerant passing noise even if the compressor 31 is variably controlled. When the after-start load is obtained from the outside air temperature, the low load is, for example, 10 ° C. If the load amount after startup is less than the low load amount, it is determined that the refrigerant passing noise is likely to be generated, and the process proceeds to step S225. On the other hand, when the load amount after startup is equal to or higher than the low load amount, it is determined that the refrigerant passing noise is unlikely to be generated, and the process proceeds to step S226.

In step S225, on / off control is executed. Since the compressor 31 is in a state after startup, the compressor 31 is driven by on / off control. In other words, the compressor 31 is in a state of sucking in a large amount of refrigerant at one time and compressing it. Therefore, it is possible to secure a large amount of circulation of the gas phase refrigerant and suppress the generation of the refrigerant passing noise. After driving the compressor 31 with on / off control, the process proceeds to step S231 while maintaining on / off control.

In step S226, variable control is executed. Since the compressor 31 is in a state after startup, the compressor 31 is driven by variable control. In other words, the compressor 31 is being driven while appropriately changing the compression capacity of the compressor 31. Therefore, the drive time of the compressor 31 can be secured longer and the frequency of starting the compressor 31 can be reduced as compared with the case of on / off control. After driving the compressor 31 with variable control, the process proceeds to step S231 while maintaining variable control.

In step S231, it is determined whether or not there is an air conditioning request. If there is no air conditioning request, the drive of the compressor 31 is stopped and the air conditioning operation is terminated. On the other hand, when there is an air conditioning request, the process returns to step S201 and repeats a series of controls. However, unlike the case where the air conditioning operation is started, the compressor 31 may be being driven in step S201. The control from step S201 to step S231 corresponds to the control content of the low noise mode. By repeatedly executing this low noise mode, the control method of the compressor 31 can be appropriately selected and executed according to changes in the surrounding environment and the progress of air conditioning operation.

According to the above-described embodiment, the air conditioning control unit 51 switches the control method of the compressor 31 at the time of starting based on the pre-start load amount, and controls the compressor 31 after the start-up based on the post-start load amount. To switch. Therefore, when the load amount changes between the state before the start-up and the state after the start-up, the control method can be switched according to the changed load amount. Therefore, the control method of the compressor 31 can be appropriately switched according to changes in the surrounding environment such as the outside air temperature. Further, the control method of the compressor 31 can be appropriately switched according to the progress of the air conditioning operation such as the difference between the internal air temperature and the target temperature.

The air conditioning control unit 51 starts the compressor 31 with variable control when the pre-start load amount is a high load amount or more, and when the post-start load amount is less than the low load amount, the air-conditioning control unit 51 starts the compressor 31. Driven by on / off control. Therefore, it is generated when the suction pulsation sound that tends to occur when the compressor 31 is started by on / off control when the load amount is high is suppressed, and when the compressor 31 is driven by variable control when the load amount is low. Easy to suppress the noise of the refrigerant passing through. Therefore, the suction pulsation sound and the refrigerant passing sound, which can cause noise, can be suppressed by switching the control method of the compressor 31.

Also in this embodiment, even if background noise information is acquired and the low noise mode is executed when the background noise is determined to be below the threshold value, and the normal mode is executed when the background noise is determined to be above the threshold value. Good.

Other Embodiments The disclosure in this specification, drawings and the like is not limited to the exemplified embodiments. The disclosure includes exemplary embodiments and modifications by those skilled in the art based on them. For example, disclosure is not limited to the parts and / or element combinations shown in the embodiments. Disclosure can be carried out in various combinations. The disclosure can have additional parts that can be added to the embodiment. Disclosures include those in which the parts and / or elements of the embodiment are omitted. Disclosures include replacements or combinations of parts and / or elements between one embodiment and the other. The technical scope disclosed is not limited to the description of the embodiments. Some technical scopes disclosed are indicated by the claims description and should be understood to include all modifications within the meaning and scope equivalent to the claims statement.

Disclosure in the description, drawings, etc. is not limited by the description of the scope of claims. The disclosure in the description, drawings, etc. includes the technical ideas described in the claims, and further covers a wider variety of technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure of the description, drawings, etc. without being bound by the description of the claims.

The control unit and its method described in the present disclosure may be realized by a dedicated computer constituting a processor programmed to perform one or more functions embodied by a computer program. Alternatively, the apparatus and method thereof described in the present disclosure may be realized by a dedicated hardware logic circuit. Alternatively, the apparatus and method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

1 Vehicle air conditioner, 10 Blower unit, 20 Air conditioner unit, 30 Refrigeration cycle device, 31 Compressor, 35 Condenser, 39 Evaporator, 40 Refrigerant pipe, 48 Expansion valve, 50 Control unit, 51 Air conditioner control unit, 52 Load Volume acquisition unit, 53 Background noise information acquisition unit, 80 Vehicle speed sensor, 91 Air conditioning sensor, 91a Outside temperature sensor, 91b Inside temperature sensor, 91c Evaporator sensor, 91d Pressure sensor, 92 Air conditioning switch

Claims (9)

A compressor (31) that compresses the refrigerant circulating in the refrigeration cycle device (30), and
A condenser (35) that condenses the gas phase refrigerant compressed by the compressor, and
An expansion valve (48) that expands the liquid phase refrigerant condensed by the condenser, and
An evaporator (39) that evaporates the liquid-phase refrigerant by exchanging heat between the liquid-phase refrigerant expanded by the expansion valve and the air provided in the vehicle interior.
A refrigerant pipe (40) that connects the compressor, the condenser, the expansion valve, and the evaporator, and allows the refrigerant to flow inside.
Equipped with a control unit (50) that controls air conditioning operation
The control unit
An air conditioning control unit (51) that controls the compressor, and
A load amount acquisition unit (52) for acquiring the load amount of the refrigeration cycle device is provided.
The compressor can switch between two control methods: on / off control in which the compression capacity at the time of driving is constant, and variable control in which the compression capacity at the time of driving can be changed.
The air conditioning control unit executes a low noise mode for switching between on / off control and variable control based on the load amount acquired by the load amount acquisition unit. apparatus. The vehicle air-conditioning device according to claim 1, wherein the air-conditioning control unit controls the compressor by the variable control when the load amount is a high load amount or more. The vehicle air-conditioning device according to claim 1 or 2, wherein the air-conditioning control unit controls the compressor by the on-off control when the load amount is less than the low load amount. The load amount acquisition unit acquires the pre-start load amount, which is the load amount before the compressor is started, and the post-start load amount, which is the load amount after the compressor is started.
The air conditioning control unit switches the control method of the compressor at the time of start-up based on the load amount before the start-up, and switches the control method of the compressor after the start-up based on the load amount after the start-up. The vehicle air conditioner described in. The air conditioning control unit starts the compressor with the variable control when the pre-start load amount is a high load amount or more, and the post-start load amount is less than the low load amount. The vehicle air conditioner according to claim 4, wherein the compressor is driven by the on / off control. Equipped with an outside air temperature sensor (91a) that measures the outside air temperature
The vehicle air conditioner according to any one of claims 1 to 5, wherein the load amount acquisition unit estimates that the higher the outside air temperature acquired by the outside air temperature sensor, the larger the load amount. A control valve used for capacity control of the compressor is provided.
The vehicle air conditioner according to any one of claims 1 to 5, wherein the load amount acquisition unit estimates that the larger the opening degree of the control valve, the larger the load amount. It is equipped with a background noise information acquisition unit (53) that acquires background noise information.
The air conditioning control unit executes the low noise mode when the background noise acquired by the background noise information acquisition unit is less than the threshold value, and executes the low noise mode when the background noise is equal to or more than the threshold value. The vehicle air conditioner according to any one of claims 1 to 7, which is not executed. Equipped with a vehicle speed sensor (80) that measures the speed of the vehicle
The vehicle air conditioner according to claim 8, wherein the background noise information acquisition unit estimates that the faster the vehicle speed acquired by the vehicle speed sensor, the greater the background noise.

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