JP3793327B2 - Heat pump type automotive air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump type automotive air conditioner that uses a refrigerant heated by engine cooling water (hot water) to heat a vehicle interior.
[0002]
[Prior art]
For example, in some recent luxury cars and one-box cars with a relatively large cabin space, the front area of the cabin (for example, the front seat) is the front so that a comfortable air conditioning can be obtained for the entire cabin. Depending on the unit, the rear area (for example, the rear seat portion such as the second seat and the third seat) is equipped with an air conditioner for automobiles commonly called a dual car air conditioner that independently conditioned the air by the rear unit.
[0003]
As this type of automotive air conditioner, for example, during heating operation, the front unit is provided with a heater core and engine cooling water is used as a heat source, while the rear unit is provided with an indoor heat exchanger called a sub-condenser. There is a system in which a high-temperature and high-pressure refrigerant compressed by a compressor is used as a heat source. This type of device is called a heat pump type air conditioner for automobiles because it heats the passenger compartment by drawing up heat from low-temperature external air in the refrigerant circulation process (refrigeration cycle).
[0004]
However, when heating operation with this type of device, for example, when the outside air temperature is low, such as in the morning in winter, the temperature of the engine cooling water is low at startup, and the rate of temperature rise of the refrigerant is not agile. It is difficult for warm air to be blown out simultaneously with the start of operation, so-called immediate warming properties are insufficient, and heating performance may be insufficient. In particular, in a one-box car with a large interior space equipped with a diesel engine, the temperature rise of the engine coolant is slower than that of a normal gasoline engine vehicle, and a large space must be heated. Heating performance tends to be insufficient. Recently, efficient direct-injection engines (gasoline and diesel) are being developed as countermeasures for exhaust gas and energy conservation, and some of them have already been put into practical use. In some cases, there is a risk of chronic heating shortage due to a decrease in the temperature of the engine cooling water (lower water temperature) accompanying a decrease in the amount of heat released.
[0005]
Therefore, the applicant of the present invention provides an outdoor heat exchanger called a sub-evaporator, and heats the return refrigerant to the compressor using the heat of engine cooling water in this sub-evaporator, and uses a higher-temperature refrigerant with increased enthalpy. Thus, a heat pump type air conditioner for automobiles that exhibits higher heating performance has been proposed (for example, see Japanese Patent Application No. 7-271621). Furthermore, on the premise of this technology, an automotive air conditioner was proposed in which both front and rear seats are heat pump systems in order to cope with the low water temperature by direct injection of the engine (see, for example, Japanese Patent Application No. 9-90854).
[0006]
The above-mentioned circumstances such as insufficient heating are not limited to dual car air conditioners, but also apply to ordinary single type heat pump car air conditioners with only one unit, so a single type with a sub-evaporator. A heat pump type air conditioner for automobiles is currently being developed.
[0007]
[Problems to be solved by the invention]
In a heat pump automotive air conditioner equipped with such a sub-evaporator, when the cycle pressure rises sufficiently when the heating operation is stable or the vehicle is running, the flow of hot water to the sub-evaporator is controlled to protect the refrigeration cycle. At the same time, the blowing temperature is kept constant.
[0008]
However, in such a conventional system, the main point is to improve the maximum heating capacity. When the maximum heating capacity is not required, for example, when the heating operation is stable, It has not yet been fully developed in terms of temperature control.
[0009]
For example, in the case of a system with a heater core downstream of the sub-condenser, the engine cooling water temperature that finally flows through the heater core is higher than the refrigerant temperature that flows through the sub-condenser. However, the temperature of the air blown into the passenger compartment cannot be lowered below the air temperature after passing through the sub capacitor. It should be noted that the engine cooling water temperature finally flowing through the heater core becomes higher than the refrigerant temperature flowing through the sub-condenser because the rise in cycle temperature is suppressed by ON / OFF control of the sub-evaporator water valve by the compressor discharge pressure. is there.
[0010]
The present invention has been made by paying attention to the above-mentioned problems in the air conditioner for heat pump automobiles currently under development by the applicant of the present invention, and provides an air conditioner for automobiles capable of adjusting the blowing temperature. With the goal.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is for heating the passenger compartment by using the heat of the refrigerant circulating while changing the state in the refrigeration cycle. In the heat pump type automotive air conditioner comprising an outdoor evaporator that heats the refrigerant that is returned to the compressor by heat exchange, an opening / closing means that opens and closes a passage for introducing engine coolant to the outdoor evaporator, and the compressor ON / OFF time ratio of the opening / closing means so that the output of the discharge pressure detecting means for detecting the pressure of the discharged refrigerant and the output of the discharge pressure detecting means becomes a control value set in advance according to a desired heating capacity possess a control means for adjusting, the compressor is driven to rotate via a belt by the engine, the refrigeration cycle , The refrigerant discharged from the compressor, at least the internal condenser, the orifice, the outdoor evaporator, and flows accumulator, characterized in that it returns to the compressor.
[0012]
According to the configuration of the present invention, the control means has a time ratio between ON and OFF of the opening / closing means so that the output of the discharge pressure detection means (compressor discharge pressure) becomes a control value set in advance according to the desired heating capacity, That is, the duty ratio is adjusted. Since the discharge temperature by the heat pump system is related to the compressor discharge pressure, the cycle pressure and temperature, especially the compressor discharge pressure, are controlled by adjusting the ON / OFF duty ratio of the opening and closing means to adjust the heat absorption amount in the outdoor evaporator. The blowout temperature can be adjusted. For example, when the maximum heating capacity is required, such as at the beginning of heating, the control value of the compressor discharge pressure is set high to increase the discharge temperature, and when the maximum heating capacity is not required, such as during temperature control, the compressor discharge pressure Decrease the control value to suppress the blowing temperature.
[0013]
The invention according to claim 2 is for heating the passenger compartment by using the heat of the refrigerant circulating while changing the state in the refrigeration cycle, and returning to the compressor by heat exchange with the engine cooling water in the refrigeration cycle. In an air conditioner for a heat pump automobile provided with an outdoor evaporator for heating the refrigerant to be cooled, an opening / closing means for opening and closing a passage for introducing engine coolant to the outdoor evaporator, and a pressure of the refrigerant discharged from the compressor a discharge pressure detection means for detecting the the output of the discharge pressure detection means have a, and control means for oN / OFF controlling said switching means at a set control range in advance depending on the desired heating capacity, the compressor In the refrigeration cycle, the engine is driven to rotate by a belt through a belt. But at least the internal condenser, flows orifice, the outdoor evaporator, and an accumulator, characterized in that it returns to the compressor.
[0014]
According to the configuration of the present invention, the control means performs ON / OFF control of the opening / closing means within a control range set in advance according to the desired heating capacity based on the output (compressor discharge pressure) of the discharge pressure detection means. As mentioned above, the temperature at which the heat pump system blows out is related to the compressor discharge pressure. Therefore, the cycle pressure / temperature, especially the compressor discharge pressure, is controlled by adjusting the ON / OFF timing of the opening / closing means to adjust the heat absorption in the outdoor evaporator. This makes it possible to adjust the blowing temperature. For example, when the maximum heating capacity is required, such as at the beginning of heating, the control range of the compressor discharge pressure is set high to increase the discharge temperature, and when the maximum heating capacity is not required, such as during temperature control, the compressor discharge pressure Lower the control range of to control the blowing temperature.
[0015]
The invention of claim 3 is the heat pump type air conditioner for a vehicle according to the claim 1 or 2, it is heated by passing through the pre-Symbol internal condenser to heat the intake air by heat exchange with the refrigerant The control means further includes a blowing temperature detecting means for detecting the temperature of the air, and the control means outputs a predetermined value when the opening / closing means prevents introduction of engine cooling water to the outdoor evaporator. When the above is true, the compressor is turned off.
[0016]
According to the configuration of the present invention, when the control means prevents the introduction of the engine cooling water to the outdoor evaporator by the opening / closing means as the first stage control, the output of the blowing temperature detecting means (air temperature after passing through the indoor condenser) is When the value is equal to or greater than the predetermined value, the compressor is turned off as the second-stage control. As a result, the cycle pressure and temperature are lowered, and the temperature of the refrigerant flowing through the indoor condenser is lowered, so that the blowing temperature is lowered. That is, even if the flow rate of hot water to the outdoor evaporator is zero, when the blowing temperature is equal to or higher than a predetermined value, the compressor is turned off to lower the blowing temperature.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a schematic configuration diagram showing a heat pump automobile air conditioner according to an embodiment of the present invention. Here, among the heat pump type dual-car air conditioners equipped with outdoor heat exchangers called sub-evaporators, a heat pump system that uses a refrigerant to heat both the front and rear seats (however, the rear seat side is heated) Only (no dehumidification)), and the front seat side illustrates a system that can also perform heating by engine cooling water (hot water).
[0019]
This automotive air conditioner is a front unit 10 and a rear unit that harmonize air inside and outside the vehicle (inside and outside air) selectively taken in by a blower (blower) and blow it out toward the front seat and rear seat in the vehicle interior, respectively. And 20.
[0020]
The front unit 10 has a ventilation path 11 formed in a casing thereof, and the cooling water (hot water) of the engine 1 is used in the ventilation path 11 in order from the downstream side in the air flow direction indicated by the white arrow. A heater core 12 that heats the intake air, a front sub-condenser 13 as an indoor condenser that constitutes a refrigeration cycle, which will be described later, a normal evaporator 14 that also constitutes a refrigeration cycle, and the blower 15 are disposed. Although not shown, in more detail, the front unit 10 includes an intake unit, a cooling unit, and a heater unit in order from the upstream side. The intake unit and the blower 15 are arranged in the intake unit. An evaporator 14 is disposed, and a front sub capacitor 13, an air mix door 16, and a heater core 12 are disposed in the heater unit. The air mix door 16 is rotatably provided on the front surface of the heater core 12 and adjusts the ratio of the air passing through the heater core 12 and the air bypassing the heater core 12 to create air at a desired temperature in the downstream area of the heater core 12. Alternatively, air is prevented from flowing through the heater core 12. In addition, various air outlets are formed on the downstream side of the heater core 12 of the heater unit to blow out the air whose temperature is adjusted after the air mixing toward the front seat in the vehicle interior.
[0021]
Further, a suction temperature sensor 17 for detecting the air temperature after passing through the evaporator 14 is provided on the downstream side of the front sub-capacitor 13 for freezing protection of the evaporator 14 during the cooling operation. The suction temperature sensor 17 also functions as a blowing temperature detection means for detecting the temperature of the air heated by passing through the front sub-capacitor 13 during heating operation. This is because when the air mix door 16 is in the fully closed position A, the warm air that has passed through the front sub-capacitor 13 is blown into the vehicle interior.
[0022]
On the other hand, the rear unit 20 has a ventilation passage 21 formed in a casing thereof, and a rear sub-capacitor 22 constituting a refrigeration cycle in the ventilation passage 21 in order from the downstream side in the air flow direction indicated by the white arrow. And the said air blower 23 is arrange | positioned. The rear sub capacitor 22 is connected in parallel with the front sub capacitor 13 and the evaporator 14 connected in series in the circuit of the refrigeration cycle. Although not shown, in more detail, the rear unit 20 includes an intake unit and a heater unit in order from the upstream side. The intake unit and the blower 23 are disposed in the intake unit, and the rear sub-capacitor 22 is disposed in the heater unit. Is arranged. On the downstream side of the sub-condenser 22 of the heater unit, a predetermined air outlet is formed for blowing out heated air toward the rear seat of the vehicle interior. In the present embodiment, since the rear unit 20 is a heating only system (no dehumidification) as described above, the evaporator and the air mix door are omitted.
[0023]
A compressor 2 and a main condenser 3 that are rotationally driven by the engine 1 via a belt (not shown) are disposed outside the units 10 and 20. In the refrigeration cycle, the compressor 2, the main condenser 3, the front sub condenser 13, the evaporator 14, and the rear sub condenser 22 are connected to the solenoid valve 16 with a front orifice and a liquid tank 24 for the rear by piping. It is connected to the solenoid valve 25 with an orifice, and a refrigerant is enclosed therein. The solenoid valves 16 and 25 with orifices are built-in orifices for refrigerant expansion (for example, φ1.45) in solenoid valves as on-off valves.
[0024]
A four-way valve 4 as a circuit switching valve is provided on the inlet side of the main capacitor 3. The four-way valve 4 is provided with one inlet port and three outlet ports in a sealed case, and a slide member that communicates two outlet ports among the three outlet ports in the case. An exit port other than the exit port is configured to communicate with the entrance port. Therefore, the exit port that communicates with the entrance port is selected depending on the position of the slide member. Here, the inlet port of the four-way valve 4 is connected to the discharge side of the compressor 2, and the three output ports of the four-way valve 4 are the inlet of the main condenser 3, the suction side of the compressor 2 (refrigerant recovery passage 5), and the main, respectively. It is connected to the outlet (bypass passage 6) of the capacitor 3. With this four-way valve 4, on the front side, the cooling operation refrigerant circuit (hereinafter simply referred to as “cooling circuit”) that guides the refrigerant discharged from the compressor 2 to the main condenser 3, and the refrigerant discharged from the compressor 2 as the main A heating operation refrigerant circuit (hereinafter simply referred to as “heating circuit”) leading to the bypass passage 6 of the condenser 3 is switched. In addition, in FIG. 1, the state of the four-way valve 4 at the time of heating operation is shown.
[0025]
In addition, outside the units 10 and 20, an outdoor evaporator is provided in the low-pressure side refrigerant passage between the suction side of the compressor 2 and the junction 7 between the front side and the rear side in order to improve the heating performance by the heat pump. A sub-evaporator 8 that functions as an (outdoor heat exchanger) is provided. The sub-evaporator 8 has a function of heating the refrigerant flowing through the inside by heat exchange with engine cooling water (hot water), and can be called a hot water-refrigerant heat exchanger.
[0026]
By providing such a sub-evaporator 8, even if it is engine cooling water that cannot be used immediately for heating even if heat is exchanged with air due to low temperature, heat exchange with the refrigerant flowing in the sub-evaporator 8 is possible. Since the refrigerant effectively takes in the heat held by the engine cooling water and is heated (that is, the enthalpy increases), it returns to the compressor 2 and is compressed and pressurized by the compressor 2 again. The refrigerant discharged from the compressor 2 becomes a higher temperature refrigerant and is supplied to the sub capacitors 13 and 22. As a result, the heat dissipating performance of the sub-capacitors 13 and 22 is enhanced, and the heat-exchanged air becomes higher in temperature, so that higher heating performance is exhibited and immediate warming is improved.
[0027]
Further, between the sub-evaporator 8 and the compressor 2, as described above, the solenoid valve 16 with an orifice having no refrigerant flow rate adjusting function is employed instead of the normal temperature type expansion valve. An accumulator 9 for separating the liquid and returning only the gas refrigerant to the compressor 2 is provided. Since the accumulator 9 is a container having a relatively large capacity for storing the refrigerant, even if the refrigerant returns in a liquid state, it can be vaporized and returned to the compressor 2, and damage to the compressor 2 due to liquid compression can be prevented. Can be prevented.
[0028]
During the heating operation, the refrigerant discharged from the compressor 2 normally flows to both the front unit 10 side and the rear unit 20 side through the next heating circuit. At this time, the two electromagnetic valves 16 and 25 for guiding the refrigerant to the front unit 10 side and the rear unit 20 side are both open. That is, during the heating operation, the refrigerant discharged from the compressor 2 flows from the four-way valve 4 to the bypass passage 6 and then branches and flows from here to the front unit 10 side and the rear unit 20 side, and then the inlet of the sub-evaporator 8 ( Merge at the junction 7) and return to the compressor 2. More specifically, in the former, the refrigerant flowing through the bypass passage 6 flows from the front sub-capacitor 13 → the orifice (solenoid valve) 16 → the evaporator 14, and then flows from the sub-evaporator 8 → the accumulator 9 to the compressor. Return to 2. In the latter case, the refrigerant flowing through the bypass passage 6 flows through the rear sub-capacitor 22 → the liquid tank 24 → the orifice (solenoid valve) 25, then flows through the sub-evaporator 8 → the accumulator 9, and returns to the compressor 2. To do. When the rear seat is not heated, the electromagnetic valve 25 is closed.
[0029]
On the other hand, during the cooling operation, the refrigerant discharged from the compressor 2 usually flows only to the front unit 10 side through the next cooling circuit. At this time, the electromagnetic valve 25 on the rear unit 20 side is in a closed state. That is, during the cooling operation, the refrigerant discharged from the compressor 2 flows through the four-way valve 4 → the main condenser 3 → the front sub condenser 13 → the orifice (solenoid valve) 16 → the evaporator 14 → the sub evaporator 8 → the accumulator 9. Return to
[0030]
An electromagnetically operated warm water valve 31 is provided at the warm water inlet of the heater core 12, and the warm water flowing out from the engine 1 is introduced into the heater core 12 by opening the warm water valve 31.
[0031]
An electromagnetically operated water valve 32 that functions as an opening / closing means is provided at the hot water inlet of the sub-evaporator 8. During the heating operation, by opening the water valve 32, hot water flowing out from the engine 1 is introduced into the sub-evaporator 8, and the sub-evaporator 8 is activated to perform the predetermined function described above.
[0032]
Although not shown in FIG. 1, a discharge pressure sensor 53 serving as discharge pressure detecting means for detecting the discharge pressure (Pd) of the compressor 2 is provided on the high pressure side of the refrigerant circuit having the above configuration (see FIG. 1). 2). When the discharge pressure of the compressor 2 rises, in order to protect the compressor 2, control for turning the compressor 2 ON / OFF according to the discharge pressure is performed.
[0033]
As described above, the refrigerant recovery passage 5 is provided between the outlet side of the four-way valve 4 (one of the outlet ports) and the suction side of the compressor 2, and this refrigerant recovery passage 5 is connected to the outside air temperature. When the engine cooling water cannot be used immediately as a heat source for heating, so-called stagnation refrigerant staying in the main condenser 3 or the like is returned to the compressor 2 so that high performance heating can be performed using a large amount of refrigerant. Is for.
[0034]
In FIG. 1, reference numeral 40 denotes an electric fan for cooling the main condenser 3, and reference numerals 41, 42, 43, 44, and 45 denote check valves for preventing flow in opposite directions.
[0035]
Next, the operation will be described. In addition, only the effect | action at the time of the heating operation to which this invention is applied is demonstrated here.
[0036]
Heating operation initial stage When the outside air temperature is low at the start of the heating operation, the temperature of the engine cooling water is also low and cannot be used immediately for heating (in the case of the heater core 12). In addition, the refrigerant is trapped in the main condenser 3 and the like, and does not exist so much in the compressor 2. When heating the front and rear seats in this state, for example, the hot water valve 31 is OFF, the flow control actuator 32 is fully open, the two electromagnetic valves 16 and 25 are both open, and the four-way valve 4 is as shown in FIG. Set to each. The air mix door 16 is set at the fully closed position A so that air does not pass through the heater core 12.
[0037]
When the compressor 2 is turned on in this state, the refrigerant sleeping mainly inside the main condenser 3 is guided to the suction side of the compressor 2 through the four-way valve 4 and the refrigerant recovery passage 5 and recovered.
[0038]
As a result, the compressor 2 enters an operation state in which a large amount of refrigerant can be discharged, and the high-temperature and high-pressure refrigerant discharged from the compressor 2 branches after flowing from the four-way valve 4 to the bypass passage 6, and a part of the front sub Capacitor 13 → Orifice (solenoid valve) 16 → flows through evaporator 14 and front unit 10 side, partly flows through rear sub-capacitor 22 → liquid tank 24 → orifice (solenoid valve) 25 and rear unit 20 side, merges At the point 7, they merge, flow from the sub-evaporator 8 to the accumulator 9, and return to the compressor 2. In this circulation process, the low-temperature and low-pressure refrigerant that has flowed into the sub-evaporator 8 is heated by heat exchange with the engine coolant, becomes higher in temperature, and is sucked into the compressor 2 and compressed again. As a result, the refrigerant that has returned to the compressor 2 and has been compressed again is increased in enthalpy (that is, the cycle balance is increased) and discharged at a higher temperature and pressure. Since the heating capacity (heat dissipation performance) of the sub-capacitors 13 and 22 is related to the temperature of the refrigerant, higher heating performance is exhibited by increasing the temperature of the discharged refrigerant in this way. In addition, since such a tendency is amplified with the passage of time, the recovery of heat from the engine cooling water can be used as a trigger, so that the refrigerant temperature can be quickly and efficiently increased. Warmness will be greatly improved.
[0039]
At this time, the air taken into the front unit 10 is dehumidified (cooled) by the evaporator 14, further heated by the front sub-capacitor 13, and then flows down and blown out from a predetermined outlet. Thereby, dehumidification heating which heats dehumidified air is realized. In addition, the air taken into the rear unit 20 is heated by the rear sub-condenser 22 and then flows down, and is blown out from a predetermined outlet into the vehicle interior to achieve heating (without dehumidification).
[0040]
When heating operation is stable When the temperature of the engine cooling water rises to some extent and the temperature in the passenger compartment also rises to some extent, the water valve 32 is controlled to be ON / OFF by a control method described later so as to keep the blowout temperature constant. The hot water flow rate to the sub-evaporator 8 is controlled.
[0041]
That is, when the engine coolant temperature rises to some extent and the warm water is introduced into the sub-evaporator 8, the discharge pressure / temperature of the compressor 2 increases with the passage of time, and the discharge temperature increases. This principle is as described above. When hot water flows through the sub-evaporator 8, the amount of heat absorbed from the hot water gradually increases and the amount of heat exchange with the refrigerant increases, so that the refrigerant temperature at the outlet of the sub-evaporator 8 increases. As a result, the refrigerant temperature sucked into the compressor 2 rises, and the discharge pressure / temperature of the compressor 2 increases as the sucked refrigerant temperature rises. Thereby, the heat dissipation capability in the sub-capacitors 13 and 22 increases, and the blowing temperature rises. On the contrary, if the inflow of warm water to the sub-evaporator 8 is blocked, the amount of heat absorption gradually decreases and the amount of heat exchange with the refrigerant decreases, so that the discharge pressure / temperature of the compressor 2 decreases and the discharge temperature decreases. Therefore, it should be possible to adjust (temperature control) the blow-out temperature by controlling the flow rate of hot water to the sub-evaporator 8 (more specifically, ON / OFF control at an appropriate timing).
[0042]
FIG. 2 is a block diagram of such a temperature control system.
[0043]
The auto amplifier 50 functioning as a control means incorporates a microcomputer, and on its input side is a system switch 51, an air conditioner switch 52, a discharge pressure sensor 53 for detecting the compressor discharge pressure (Pd), and after passing through the sub capacitor 13. A suction temperature sensor 17 for detecting the air temperature is connected, and a compressor 2 (magnet clutch) and a water valve 32 for the sub-evaporator 8 are connected to the output side. The system switch 51 is an operation switch for operating a heating system using the sub-evaporator 8, and the air conditioner switch is an operation switch for operating as a normal cooling / heating system that does not use the sub-evaporator 8. The auto amplifier 50 operates the heating system using the sub-evaporator 8 when the system switch 51 is ON and the air conditioner switch 52 is OFF. Among them, the compressor 2 and the water valve 32 for temperature control are operated. Perform ON / OFF control.
[0044]
First, the first control method will be described.
[0045]
Here, as the first-stage control, the blowout temperature control is performed by ON / OFF control of the water valve 32 by the compressor discharge pressure. At this time, the water valve 32 is opened and closed (ON / OFF) by duty control. Thereafter, even when the water valve 32 is closed and the flow rate of hot water to the sub-evaporator 8 is zero (0), if the blowing temperature is equal to or higher than the predetermined temperature, the compressor 2 is turned off and blown as a second stage control. Reduce the temperature.
[0046]
Details of the control in the first stage are as follows. Here, the amount of heat absorbed in the sub-evaporator 8 is adjusted by changing the ON / OFF time ratio of the water valve 32 for the sub-evaporator 8, that is, the duty ratio, thereby controlling the compressor discharge pressure (Pd). Control the blowing temperature. More specifically, the ON / OFF duty ratio of the water valve 32 is adjusted so that the compressor discharge pressure (Pd) becomes a control value set in advance according to the desired heating capacity.
[0047]
As shown in FIG. 3, when the water valve 32 is opened (ON), since hot water is introduced into the sub-evaporator 8, the amount of heat absorbed by the sub-evaporator 8 increases with time, thereby increasing the compressor discharge pressure. In addition, when the water valve 32 is closed (OFF), the hot water is not introduced into the sub-evaporator 8, so that the heat absorption amount of the sub-evaporator 8 decreases with time, and the compressor discharge pressure also decreases. Therefore, by appropriately setting the ON / OFF duty ratio of the water valve 32, it is possible to adjust the heat absorption amount of the sub-evaporator 8, and thus the compressor discharge pressure (Pd), and the discharge temperature to a certain level (range). It becomes. At this time, as a method for adjusting the ON / OFF duty ratio of the water valve 32, for example, as shown in FIG. 4, the ON time is fixed to 1 second, and the OFF time is changed in units of 1 second. The longer the OFF time, the lower the endothermic level and the lower the compressor discharge pressure and blowout temperature.
[0048]
A specific example of the control is as follows. First, as shown in FIG. 5, when the maximum heating capacity is required such as during initial heating, that is, in the initial setting during heating, the control value of the compressor discharge pressure is set high to increase the discharge temperature. For example, the ON / OFF duty ratio of the water valve 32 is adjusted so that the compressor discharge pressure (Pd) becomes 20 kg / cm 2 G. At this time, the blowing temperature is about 55 ° C. Next, when the maximum heating capacity is not required, such as during temperature adjustment (when the heating operation is stable), the control value of the compressor discharge pressure is lowered to suppress the discharge temperature. For example, the ON / OFF duty ratio of the water valve 32 is changed so that the compressor discharge pressure (Pd) becomes 15 kg / cm 2 G. At this time, the blowing temperature is about 45 ° C. In addition, at the time of temperature adjustment, the duty ratio may be adjusted as appropriate so that the compressor discharge pressure corresponding to a desired blowing temperature is obtained.
[0049]
In such duty control of the water valve 32, even if the water valve 32 is closed (OFF) and the flow rate of the hot water to the sub-evaporator 8 is set to zero (0), the blow-out temperature at that time is equal to or higher than the target desired temperature. In this case, as described above, the compressor 2 is turned off and the blowing temperature is lowered as the second-stage control.
[0050]
Therefore, according to the first control method, the blowout temperature can be adjusted (temperature control), and the amount of heat absorption, cycle pressure and temperature can be kept within a certain range by duty control of the water valve 32. Therefore, it is possible to reduce the hunting of the blowing temperature during temperature control.
[0051]
Next, the second control method will be described.
[0052]
Here, as the first-stage control, the blowout temperature control is performed by ON / OFF control of the water valve 32 by the compressor discharge pressure. At this time, the water valve 32 is opened and closed (ON / OFF) within a control range including an upper limit value and a lower limit value related to the compressor discharge pressure. Thereafter, even when the water valve 32 is closed and the flow rate of hot water to the sub-evaporator 8 is zero (0), if the blowing temperature is equal to or higher than the predetermined temperature, the compressor 2 is turned off and blown as a second stage control. Reduce the temperature.
[0053]
Details of the control in the first stage are as follows. Here, the heat absorption amount in the sub-evaporator 8 is adjusted by changing the ON / OFF switching timing of the water valve 32 for the sub-evaporator 8 to control the compressor discharge pressure (Pd), thereby controlling the blow-off temperature. Control. More specifically, the water valve 32 is turned on / off within a control range set in advance according to the desired heating capacity for the compressor discharge pressure (Pd).
[0054]
For example, as shown in FIG. 6, the water valve 32 is closed (OFF) when the compressor discharge pressure becomes the upper limit value Pd1 or more with the water valve 32 turned on, and the water valve 32 is turned off when the compressor discharge pressure becomes the lower limit value Pd2 or less with the water valve 32 turned off. Open (ON). When the water valve 32 is opened (ON), hot water is introduced into the sub-evaporator 8, so that the amount of heat absorbed by the sub-evaporator 8 increases with time, thereby increasing the compressor discharge pressure, but when the water valve 32 is closed (OFF) ) Since no hot water is introduced into the sub-evaporator 8, the amount of heat absorbed by the sub-evaporator 8 decreases with time, and the compressor discharge pressure also decreases. Therefore, by appropriately setting the ON / OFF switching timing of the water valve 32, it is possible to adjust the heat absorption amount of the sub-evaporator 8, and consequently the compressor discharge pressure (Pd), and the discharge temperature to a certain level (range). It becomes possible.
[0055]
A specific example of the control is as follows. First, as shown in FIGS. 7 and 8, when the maximum heating capacity is required such as during initial heating, that is, in the initial setting during heating, the upper and lower control values (Pd1, Pd2) of the compressor discharge pressure are set high. And raise the blowing temperature. For example, the control range of the compressor discharge pressure (Pd) is set to 17 to 20 kg / cm 2 G, and the water valve 32 is turned ON / OFF in this control range. At this time, the blowing temperature is about 55 ° C. Next, when the maximum heating capacity is not required, such as when temperature is controlled (when the heating operation is stable), the control values (Pd1, Pd2) of the upper and lower limits of the compressor discharge pressure are lowered to suppress the discharge temperature. For example, the control range of the compressor discharge pressure (Pd) is lowered to 15 to 17 kg / cm @ 2 G, and the water valve 32 is turned ON / OFF within this range. At this time, the blowing temperature is about 45 ° C. In addition, at the time of temperature control, the control range may be changed as appropriate so that the compressor discharge pressure corresponding to a desired blowing temperature is obtained.
[0056]
In such ON / OFF switching control of the water valve 32, even if the water valve 32 is closed (OFF) and the flow rate of the hot water to the sub-evaporator 8 is set to zero (0), the desired blow-out temperature at that time is a desired target. When the temperature is equal to or higher than the temperature, as described above, the compressor 2 is turned off and the blowing temperature is lowered as the second-stage control.
[0057]
Therefore, the second control method can also adjust (temperature control) the blowing temperature.
[0058]
In addition, according to the first and second control methods, since both are controlled by the auto amplifier 50, there are no new parts relating to temperature control, and an increase in cost can be avoided.
[0059]
In the above-described embodiment, a system in which only the rear seat side is heated (no dehumidification) is shown. However, the present invention is not limited to this, and an evaporator is provided in the rear unit 20 as in the front unit 10. Thus, a system that can perform dehumidification heating may be used.
[0060]
Further, in the above-described embodiment, a dual car air conditioner that can heat both the front and rear seats has been described as an example. However, the present invention is not limited to this, and the present invention is a heat pump type automobile air equipped with a sub-evaporator. If it is a harmony device, it can be applied to any type including a single type heat pump system. Therefore, it is not always necessary to provide both the sub capacitor and the heater core as a heating heat source in one unit as in the above-described embodiment.
[0061]
【The invention's effect】
As described above, according to the first aspect of the invention, the ON / OFF duty ratio of the opening / closing means is adjusted so that the compressor discharge pressure becomes a predetermined control value according to the desired heating capacity. The amount of heat absorbed in the outdoor evaporator is adjusted, and the blowout temperature can be adjusted.
[0062]
According to the second aspect of the present invention, since the opening / closing means is turned on / off within a predetermined control range corresponding to the desired heating capacity by the compressor discharge pressure, the heat absorption amount in the outdoor evaporator is adjusted, and the blowout temperature is adjusted. It becomes possible.
[0063]
According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the compressor is turned off when the discharge temperature is equal to or higher than a predetermined value even if the flow rate of hot water to the outdoor evaporator is zero. The blowing temperature can be surely lowered and the temperature control performance is improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a heat pump automotive air conditioner according to an embodiment of the present invention.
FIG. 2 is a block diagram of a temperature control system in the apparatus of FIG.
FIG. 3 is a graph showing a relationship between ON / OFF of a water valve and an endothermic amount.
FIG. 4 is a chart for explaining how to change the ON / OFF time ratio of the water valve.
FIG. 5 is a graph showing a specific example to which the first control method is applied.
FIG. 6 is a control characteristic diagram of ON / OFF of a water valve.
FIG. 7 is an explanatory diagram of a second control method.
FIG. 8 is a graph showing a specific example to which the method is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Compressor 8 ... Sub-evaporator (Outdoor evaporator)
10 ... Front unit 12 ... Heater core 13 ... Front sub capacitor (indoor capacitor)
14 ... Evaporator 17 ... Suction temperature sensor (blowing temperature detection means)
20 ... Rear unit 22 ... Rear sub capacitor 32 ... Water valve (opening / closing means)
50 ... Auto-amplifier (control means)
53. Discharge pressure sensor (discharge pressure detecting means)

Claims (3)

Heating of the passenger compartment is performed using the heat of the refrigerant circulating while changing the state in the refrigeration cycle, and the outdoor heating the refrigerant returning to the compressor (2) by heat exchange with the engine cooling water in the refrigeration cycle. In an air conditioner for a heat pump type automobile provided with an evaporator (8),
Opening and closing means (32) for opening and closing a passage for introducing engine coolant to the outdoor evaporator (8);
A discharge pressure detecting means (53) for detecting the pressure of the refrigerant discharged from the compressor (2);
Control means (50) for adjusting the ON / OFF time ratio of the opening / closing means (32) so that the output of the discharge pressure detecting means (53) becomes a control value set in advance according to a desired heating capacity; ,
Have a,
The compressor (2) is rotationally driven through a belt by the engine (1), and in the refrigeration cycle, the refrigerant discharged from the compressor (2) is at least an indoor condenser (13), an orifice (16), and the A heat pump type automobile air conditioner that flows through the outdoor evaporator (8) and the accumulator (9) and returns to the compressor (2) . Heating of the passenger compartment is performed using the heat of the refrigerant circulating while changing the state in the refrigeration cycle, and the outdoor heating the refrigerant returning to the compressor (2) by heat exchange with the engine cooling water in the refrigeration cycle. In an air conditioner for a heat pump type automobile provided with an evaporator (8),
Opening and closing means (32) for opening and closing a passage for introducing engine coolant to the outdoor evaporator (8);
A discharge pressure detecting means (53) for detecting the pressure of the refrigerant discharged from the compressor (2);
Control means (50) for ON / OFF controlling the opening / closing means (32) within a control range set in advance according to the desired heating capacity by the output of the discharge pressure detecting means (53);
Have a,
The compressor (2) is rotationally driven through a belt by the engine (1), and in the refrigeration cycle, the refrigerant discharged from the compressor (2) is at least an indoor condenser (13), an orifice (16), and the A heat pump type automobile air conditioner that flows through the outdoor evaporator (8) and the accumulator (9) and returns to the compressor (2) . It further has blowing temperature detecting means (17) for detecting the temperature of air heated by passing through the indoor condenser (13) for heating the intake air by heat exchange with the refrigerant ,
When the control means (50) prevents the introduction of engine cooling water to the outdoor evaporator (8) by the opening / closing means (32), the output of the blowing temperature detecting means (17) is a predetermined value or more. The heat pump type automobile air conditioner according to claim 1 or 2, wherein the compressor (2) is turned off.

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