JPH1134643A - Heat pump vehicle air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for adjusting the air blow off temperature of a heat pump vehicle air conditioner provided with a sub-evaporator which heats a cabin by using coolant and hot water. SOLUTION: An ON/OFF duty ratio of a water valve is adjusted for compressor discharge pressure to attain a previously set control value according to a desired heating ability. For example, at the initial setting for heating, a control value for the compressor discharge pressure is set high to increase an air blow off temperature. In controling the temperature, a control value for compressor discharge pressure is lowered to suppress the air blow off temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner for a vehicle which heats a vehicle interior by using a refrigerant heated by engine cooling water (warm water).

[0002]

2. Description of the Related Art For example, in recent luxury cars and one-box cars having a relatively large interior space, a front area (for example, a front area) in the interior of the vehicle is required so that a comfortable air-conditioning state can be obtained for the entire interior. Seat part) by the front unit,
A rear area (for example, a rear seat portion such as a second seat and a third seat) is mounted with an air conditioner for a vehicle, which is generally called a dual car air conditioner, in which air is independently conditioned by a rear unit.

As this type of air conditioner for automobiles, for example, during a heating operation, a front unit is provided with a heater core and uses engine cooling water as a heat source, while a rear unit is 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 by providing a heat exchanger. This type of device is called a heat pump type air conditioner for a vehicle because it heats a vehicle interior by drawing heat from low-temperature external air in a refrigerant circulation process (refrigeration cycle).

[0004] However, when a heating operation is performed with this type of device, for example, when the outside air temperature is low, such as in the morning of winter, the temperature of the engine cooling water is low at the time of startup, and the temperature of the refrigerant rises rapidly. Therefore, a state in which warm air is blown out at the same time as the start of operation is unlikely to occur, so-called instantaneous warming becomes insufficient, and the heating performance may be insufficient. In particular, in a one-box car with a large cabin space equipped with a diesel engine, the temperature of the engine cooling water rises slowly compared to a normal gasoline engine car, and since it has to heat a large space, immediate warming, Heating performance tends to be insufficient.
Recently, efficient direct-injection engines (gasoline and diesel) have been developed as exhaust gas and energy-saving measures, and some of them have already been put into practical use. in case of,
Due to a decrease in the temperature of the engine cooling water (lower water temperature) due to a decrease in the amount of heat radiation, there is a possibility that chronic insufficient heating may occur.

Therefore, the applicant of the present application has provided an outdoor heat exchanger called a sub-evaporator, in which heat of the engine cooling water is used to heat the return refrigerant to the compressor, and the enthalpy is increased. We have proposed a heat pump type air conditioner for a vehicle that exhibits higher heating performance by using a refrigerant (for example, see Japanese Patent Application No. 7-271621). Furthermore, on the premise of this technology, in order to cope with low water temperature due to direct injection of the engine, an air conditioner for automobiles having heat pump systems for both front and rear seats has been proposed (for example, Japanese Patent Application No. 9-90).
No. 854).

[0006] The above-mentioned situation such as insufficient heating is not limited to the case of a dual car air conditioner, but also applies to a normal single type heat pump car air conditioner having only one unit. A single type heat pump type air conditioner for automobiles is also being developed.

[0007]

In a heat pump type vehicle air conditioner equipped with such a sub-evaporator, when the cycle pressure is sufficiently increased during a stable heating operation or when the vehicle is running, the flow rate of hot water to the sub-evaporator is reduced. By controlling the refrigeration cycle, the blowout temperature is kept constant.

However, in such a conventional system, the main purpose is to improve the maximum heating capacity. When the maximum heating capacity is not required, for example, when the heating operation is stable such as when the heating operation is stable, the blowing temperature is increased. Adjustment of the temperature (so-called temperature control) has not yet been fully developed.

For example, in a system in which a heater core is provided downstream of the sub-condenser, the temperature of the engine cooling water finally flowing through the heater core becomes higher than the temperature of the refrigerant flowing through the sub-condenser. No matter how the air temperature is controlled, the temperature of the air blown into the vehicle cabin cannot be reduced below the air temperature after passing through the sub-condenser. The reason that the temperature of the engine cooling water finally flowing through the heater core becomes higher than the temperature of the refrigerant flowing through the sub-condenser is because the rise of the cycle temperature is suppressed by ON / OFF control of the water valve for the sub-evaporator by the compressor discharge pressure. is there.

The present invention has been made in view of the above-mentioned problems in a heat pump type air conditioner for a vehicle currently being developed by the present applicant. The purpose is to provide.

[0011]

In order to achieve the above object, the invention according to the first aspect heats the interior of a vehicle cabin by utilizing the heat of a refrigerant circulating while changing the state in a refrigeration cycle. In a heat pump type automotive air conditioner provided with an outdoor evaporator for heating a refrigerant returning to a compressor by heat exchange with engine cooling water in the refrigeration cycle, a passage for introducing engine cooling water to the outdoor evaporator is provided. Opening and closing means for opening and closing, discharge pressure detection means for detecting the pressure of the refrigerant discharged from the compressor, and the output pressure of the discharge pressure detection means so that the output is a control value set in advance according to the desired heating capacity A control means for adjusting a time ratio between ON and OFF of the opening / closing means is provided.

According to the structure of the present invention, the control means controls ON / OFF of the opening / closing means so that the output of the discharge pressure detecting means (compressor discharge pressure) has a control value set in advance according to a desired heating capacity. Adjust the time ratio, that is, the duty ratio. Since the blow-out temperature of the heat pump system is related to the compressor discharge pressure, the cycle pressure / temperature, particularly the compressor discharge pressure, is controlled by adjusting the ON / OFF duty ratio of the opening / closing means to adjust the amount of heat absorbed in the outdoor evaporator. Thus, it is possible to adjust the blowing temperature. 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 blowout temperature, and when the maximum heating capacity is not required, such as during temperature control, the compressor discharge pressure And control the blowing temperature.

According to a second aspect of the present invention, the interior of the vehicle compartment is heated by utilizing the heat of the refrigerant circulating while changing the state in the refrigeration cycle. In a heat pump type vehicle air conditioner provided with an outdoor evaporator for heating a refrigerant returning to a compressor, an opening / closing means for opening and closing a passage for introducing engine cooling water to the outdoor evaporator, and a refrigerant discharged from the compressor Discharge pressure detecting means for detecting the pressure of the fuel cell, and control means for controlling ON / OFF of the opening / closing means in a control range preset according to a desired heating capacity by an output of the discharge pressure detecting means. And

According to the structure of the present invention, the control means controls ON / OFF of the opening / closing means in a control range which is set in advance in accordance with a desired heating capacity by the output of the discharge pressure detecting means (compressor discharge pressure). As described above, the outlet temperature of the heat pump system is related to the compressor discharge pressure. Therefore, the ON / OFF timing of the opening / closing means is adjusted to adjust the amount of heat absorbed in the outdoor evaporator, and the cycle pressure / temperature, particularly the compressor discharge pressure, is controlled. 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 blowout temperature. When the maximum heating capacity is not required, such as during temperature control, the compressor discharge pressure And control the blowout temperature.

According to a third aspect of the present invention, in the heat pump type air conditioner for a vehicle according to the first or second aspect, the indoor condenser is provided in the refrigeration cycle and heats intake air by heat exchange with a refrigerant. And a blowout temperature detecting means for detecting a temperature of air heated by passing through the indoor condenser, wherein the control means prevents the introduction of engine cooling water to the outdoor evaporator by the opening / closing means. Wherein the compressor is turned off when the output of the blow-out temperature detecting means is equal to or higher than a predetermined value.

According to the structure of the present invention, the control means outputs the output of the blow-out temperature detection means (the air after passing through the indoor condenser) when the opening / closing means inhibits the introduction of the engine cooling water into the outdoor evaporator as the first-stage control. When the temperature is equal to or higher than the predetermined value, the compressor is turned off as the control of the second stage. As a result, the cycle pressure and temperature decrease and the temperature of the refrigerant flowing through the indoor condenser decreases, so that the blow-out temperature decreases. That is, even if the flow rate of hot water to the outdoor evaporator is set to zero, if the blowout temperature is equal to or higher than the predetermined value, the compressor is turned off to lower the blowout temperature.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a heat pump type air conditioner for a vehicle according to an embodiment of the present invention. Here, among the heat pump type dual car air conditioners equipped with an outdoor heat exchanger called a sub-evaporator, a heat pump system that uses refrigerant for both front and rear seats is adopted (however, the rear seat side is heated Only (no dehumidification)), and a system that can also perform heating with engine cooling water (hot water) on the front seat side is illustrated.

The air conditioner for a vehicle includes a front unit 10 that conditioned air (inside / outside air) inside and outside the vehicle compartment selectively taken in by a blower (blower) and blows the air toward front and rear seats in the vehicle compartment. And rear unit 20
And

The front unit 10 has a ventilation passage 11 formed in a casing thereof. In the ventilation passage 11, cooling water (hot water) for the engine 1 is arranged in order from the downstream in the direction of air flow indicated by the white arrow. And a front sub-condenser 13 as an indoor condenser constituting a refrigeration cycle to be described later.
A normal evaporator 14 and a blower 15 are also provided. Although not shown, in more detail, the front unit 10
An intake unit, a cooling unit, and a heater unit are arranged in order from the upstream side. The intake unit and the blower 15 are arranged in the intake unit, the evaporator 14 is arranged in the cooling unit, and the front sub-condenser 13 and the air are arranged in the heater unit. The mix door 16 and the heater core 12 are arranged. The air mix door 16 is rotatably provided on the front surface of the heater core 12 and adjusts the ratio of air passing through the heater core 12 and air bypassing the heater core 12 to produce air at a desired temperature in the downstream region of the heater core 12. Or heater core 12
To prevent air from circulating. Various outlets are formed downstream of the heater core 12 of the heater unit to blow out the temperature-adjusted air after the air mixing toward the front seats in the vehicle compartment.

Further, a suction temperature sensor 17 for detecting the air temperature after passing through the evaporator 14 is provided downstream of the front sub-condenser 13 to protect the evaporator 14 from freezing during the cooling operation. The suction temperature sensor 17 also functions as an outlet temperature detecting means for detecting the temperature of the air heated by passing through the front sub-condenser 13 during the heating operation. This is because when the air mix door 16 is at the fully closed position A, the warm air that has passed through the front sub-condenser 13 is blown into the vehicle interior.

On the other hand, the rear unit 20 has a ventilation passage 21 formed in a casing thereof.
A rear sub-condenser 22 constituting the refrigeration cycle and the blower 23 are disposed in this order from the downstream side in the air flow direction indicated by the white arrow. Rear sub capacitor 2
2 is a front sub-condenser 13 and an evaporator 1 connected in series in the circuit of the refrigeration cycle.
4 in parallel. Although not shown, in more detail, the rear unit 20 includes an intake unit and a heater unit in order from the upstream side, an intake door and a blower 23 are arranged in the intake unit, and a rear sub-condenser 22 is arranged in the heater unit. Is arranged. On the downstream side of the sub-condenser 22 of the heater unit, a predetermined outlet for blowing heated air toward the rear seat of the vehicle compartment is formed. In the present embodiment, since the rear unit 20 is a system for heating only (no dehumidification) as described above, the evaporator and the air mixing door are omitted.

Outside these two units 10 and 20,
A compressor 2 rotatably driven by an engine 1 via a belt (not shown) and a main condenser 3 are provided. In the refrigeration cycle, the compressor 2 and the main condenser 3, the front sub-condenser 13, the evaporator 14, and the rear sub-condenser 22 are connected by piping to a solenoid valve 16 with an orifice for front, a liquid tank 24 for rear and It is connected to an orifice-equipped solenoid valve 25, and a refrigerant is sealed therein. Solenoid valve with orifice 16, 2
Reference numeral 5 denotes a solenoid valve serving as an opening / closing valve having a built-in orifice (for example, φ1.45) for expanding the refrigerant.

On the inlet side of the main condenser 3, a four-way valve 4 is provided as a circuit switching valve. This four-way valve 4
Is provided with one inlet port and three outlet ports in the closed case, and a slide member communicating the two outlet ports among the three outlet ports is provided in the case, and the outlet port selected by the slide member is provided. The other outlet ports are configured to communicate with the inlet port. Therefore, an outlet port communicating with the inlet port is selected depending on the position of the slide member. Here, the inlet port of the four-way valve 4 is the compressor 2
And the three output ports of the four-way valve 4
The inlet of the main condenser 3 and the compressor 2
And the outlet of the main condenser 3 (bypass passage 6). This four-way valve 4
Thus, on the front side, a refrigerant circuit for cooling operation (hereinafter, simply referred to as a “cooling circuit”) that guides refrigerant discharged from the compressor 2 to the main condenser 3 and a refrigerant discharged from the compressor 2 bypasses the main condenser 3 A refrigerant circuit for heating operation (hereinafter simply referred to as “heating circuit”) that leads to the passage 6 is switched. FIG. 1 shows the state of the four-way valve 4 during the heating operation.

In order to enhance the heating performance by the heat pump, a junction 7 between the suction side of the compressor 2 and the front and rear sides is provided outside the units 10 and 20.
A sub-evaporator 8 functioning as an outdoor evaporator (an outdoor heat exchanger) is provided in the low-pressure side refrigerant passage between the sub-evaporator 8 and the low evaporator. The sub-evaporator 8 has a function of heating the refrigerant flowing therethrough by heat exchange with engine cooling water (hot water), and can be called a hot water-refrigerant heat exchanger.

By providing such a sub-evaporator 8, even if the engine cooling water cannot be used immediately for heating even if it exchanges heat with air due to low temperature, heat exchange with the refrigerant flowing into the sub-evaporator 8 is performed. By doing so, the refrigerant effectively takes in the heat of the engine cooling water and is heated (that is, the enthalpy is increased), then returns to the compressor 2 and is compressed and pressurized by the compressor 2 again. Therefore, the refrigerant discharged from the compressor 2 becomes a higher-temperature refrigerant and is supplied to the sub-condensers 13 and 22. As a result, the heat radiation performance of the sub-capacitors 13 and 22 is enhanced, and the air that has been heat-exchanged there becomes higher in temperature, so that a higher heating performance is exhibited and the immediate warming property is also improved.

Also, between the sub-evaporator 8 and the compressor 2, as described above, the solenoid valve 1 with an orifice having no refrigerant flow control function is used instead of a normal temperature-type expansion valve.
6, an accumulator 9 for storing excess refrigerant and separating gas-liquid and returning only 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.

During the heating operation, the refrigerant discharged from the compressor 2 normally flows to both the front unit 10 and the rear unit 20 through the next heating circuit. At this time, the two solenoid 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 flowing out of the compressor 2 is supplied to the four-way valve 4 → the bypass passage 6
After flowing to the front unit 10 side and the rear unit 20 side, they flow together, merge at the inlet of the sub-evaporator 8 (the junction 7), and return to the compressor 2. More specifically, in the former, the bypass passage 6
Flows through the front sub-condenser 13 → orifice (with a solenoid valve) 16 → evaporator 14, then flows through the sub-evaporator 8 → accumulator 9, and
It returns to the compressor 2. In the latter case, the refrigerant flowing through the bypass passage 6 is supplied to the rear sub-condenser 22
→ Liquid tank 24 → Orifice (with solenoid valve) 25
Flows through the sub-evaporator 8 → the accumulator 9 and returns to the compressor 2. When the rear seat is not heated, the solenoid valve 25 is closed.

On the other hand, during the cooling operation, the refrigerant discharged from the compressor 2 normally flows only to the front unit 10 side through the next cooling circuit. At this time, the solenoid valve 25 on the rear unit 20 side is in a closed state. That is,
During the cooling operation, the refrigerant flowing out of the compressor 2 is supplied to the four-way valve 4.
→ Main condenser 3 → Front sub condenser 13 →
The orifice (with a solenoid valve) 16 → the evaporator 14 → the sub-evaporator 8 → the accumulator 9 flows back to the compressor 2.

An electromagnetically operated hot water valve 31 is provided at the hot water inlet of the heater core 12. By opening the hot water valve 31, hot water flowing out of the engine 1 is introduced into the heater core 12.

The warm water inlet of the sub-evaporator 8 is provided with an electromagnetically operated water valve 32 functioning as an opening / closing means. During the heating operation, by opening the water valve 32, the hot water flowing out of the engine 1 is introduced into the sub-evaporator 8, and the sub-evaporator 8 is operated to exhibit the above-mentioned predetermined function.

Further, on the high pressure side of the refrigerant circuit having the above structure,
Although not shown in FIG. 1, a discharge pressure sensor 53 is provided as discharge pressure detecting means for detecting the discharge pressure (Pd) of the compressor 2 (see FIG. 2). When the discharge pressure of the compressor 2 rises, the compressor 2 is turned ON / OFF according to the discharge pressure to protect the compressor 2.
Control to turn off is performed.

As described above, the refrigerant recovery passage 5 is provided between the outlet side (one of the outlet ports) of the four-way valve 4 and the suction side of the compressor 2. When the outside air temperature is low and the engine cooling water cannot be used immediately as a heat source for heating, the so-called sleeping refrigerant remaining in the main condenser 3 and the like is returned to the compressor 2, and high-performance heating can be performed using a large amount of refrigerant. That's what we do.

In FIG. 1, reference numeral 40 denotes a main capacitor 3
Electric fans for cooling the
Reference numerals 3, 44 and 45 are check valves for preventing flow in opposite directions.

Next, the operation will be described. Here,
Only the operation during the heating operation to which the present invention is applied will be described.

[0036] When the outside air temperature during heating operation initial heating operation start is low, the temperature of the engine cooling water is low, it can not be used for immediate heating it (for heater core 12). In addition, the refrigerant is also buried inside the main condenser 3 and the like, and is not much present in the compressor 2. When heating the front and rear seats in this state, for example, the hot water valve 31 is turned off.
FF state, the flow control actuator 32 is fully open, the two solenoid valves 16 and 25 are both open, and the four-way valve 4 is
Are set to the states shown in the table. The air mix door 16 is set at the fully closed position A so that air does not pass through the heater core 12.

When the compressor 2 is turned on in this state,
Refrigerant mainly stored 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 is recovered.

As a result, the compressor 2 is brought into an operating state in which a large amount of refrigerant can be discharged, and the high-temperature and high-pressure refrigerant discharged from the compressor 2 flows from the four-way valve 4 to the bypass passage 6 and then branches off. Is the front sub capacitor 1
3 → orifice (with solenoid valve) 16 → evaporator 14
Part of the flow passes through the rear sub-condenser 22 → liquid tank 24 → orifice (with solenoid valve) 25 and the rear unit 20 side, and merges at the junction 7 to form the sub-evaporator 8 → accumulator 9 Flows back to the compressor 2. In this circulation process, the low-temperature and low-pressure refrigerant flowing into the sub-evaporator 8
It is heated by heat exchange with the engine cooling water, becomes higher in temperature, is sucked into the compressor 2, and is compressed again. As a result, the refrigerant that has returned to the compressor 2 and is compressed again has a higher enthalpy (that is, a higher cycle balance) and is discharged at a higher temperature and a higher pressure. Since the heating capacity (radiation performance) of the sub-condensers 13 and 22 is related to the temperature of the refrigerant, a higher heating performance is exhibited by increasing the temperature of the discharged refrigerant in this way. Further, since such a tendency is amplified with the passage of time, the recovery of the heat from the engine cooling water can be used as a trigger so that the refrigerant temperature can be raised quickly and efficiently. Warmness will also be greatly improved.

At this time, the air taken into the front unit 10 is dehumidified (cooled) by the evaporator 14, heated by the front sub-condenser 13, flows down, and is blown out from a predetermined outlet into the vehicle interior. You.
As a result, dehumidifying heating for heating dehumidified air is realized. Further, the air taken into the rear unit 20 flows down after being heated by the rear sub-condenser 22,
The air is blown out from a predetermined air outlet into the vehicle interior, and heating (no dehumidification) is realized.

When the temperature of the engine cooling water rises to a certain extent when the heating operation is stable and the temperature of the vehicle interior also rises to a certain extent, the outlet temperature is kept constant.
The water valve 32 is turned ON / O by a control method described later.
By performing FF control, the flow rate of hot water to the sub-evaporator 8 is controlled.

That is, when the temperature of the engine cooling water rises to some extent, when the warm water is introduced into the sub-evaporator 8, the discharge pressure of the compressor 2 with time elapses.
The temperature rises and the blowing temperature rises. This principle has already been described. When warm water flows into the sub-evaporator 8, the amount of heat absorbed from the warm 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 rises. Thus, the temperature of the refrigerant sucked into the compressor 2 rises, and the discharge pressure and temperature of the compressor 2 increase with the rise in the temperature of the sucked refrigerant. As a result, the heat radiation capability of the sub-capacitors 13 and 22 increases, and the blowout temperature increases. Conversely, when the flow of warm water into the sub-evaporator 8 is prevented, the amount of heat absorbed gradually decreases and the amount of heat exchange with the refrigerant decreases, so that the discharge pressure and temperature of the compressor 2 decrease, and the blow-out temperature decreases. Therefore, the flow rate of hot water to the sub-evaporator 8 is controlled (more specifically,
By performing ON / OFF control at an appropriate timing), the blowout temperature should be adjusted (temperature control).

FIG. 2 is a block diagram of such a temperature control system.

Auto-amplifier 50 functioning as control means
Has a built-in microcomputer, a system switch 51, an air conditioner switch 52, a discharge pressure sensor 53 for detecting a compressor discharge pressure (Pd), and a suction temperature sensor for detecting an air temperature after passing through the sub-condenser 13 on its input side. 17 is connected to the output of the compressor 2
(The magnetic clutch of) and the water valve 32 for the sub-evaporator 8 are connected. 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 and heating system not using the sub-evaporator 8.
When the system switch 51 is ON and the air conditioner switch 52 is OFF, the auto amplifier 50 operates the heating system using the sub-evaporator 8, in which the compressor 2 and the water valve 32 for controlling the temperature are controlled. Perform ON / OFF control.

First, the first control method will be described.

Here, as the control of the first stage, the blow-off temperature control is performed by ON / OFF control of the water valve 32 by the compressor discharge pressure. At this time, opening and closing (ON / OFF) of the water valve 32 is performed by duty control. Thereafter, even if the water valve 32 is closed and the flow rate of hot water to the sub-evaporator 8 is zero (0), if the blow-out temperature is equal to or higher than a predetermined temperature, as a second-stage control, the compressor 2 is turned off and blow-out is performed. Decrease temperature.

The 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, to control 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 a desired heating capacity.

As shown in FIG. 3, 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. However, conversely, when the water valve 32 is closed (OFF), the amount of heat absorbed by the sub-evaporator 8 decreases with time because hot water is not introduced into the sub-evaporator 8, whereby 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 amount of heat absorbed by the sub-evaporator 8, that is, the compressor discharge pressure (Pd) and the outlet temperature to a certain level (range). Becomes At this time, as a method of adjusting the ON / OFF duty ratio of the water valve 32, for example, as shown in FIG.
The time is fixed to one second, and the OFF time is changed in units of one second. The longer the OFF time, the lower the level of heat absorption, and the lower the compressor discharge pressure and blowout temperature.

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 blowout temperature. For example, when the compressor discharge pressure (Pd) is 20
ON / OFF of the water valve 32 so that the pressure becomes kg / cm2G.
Adjust the duty ratio of F. At this time, the blowing temperature is about 55 ° C. Next, when the maximum heating capacity is not required, such as at the time of temperature control (when the heating operation is stable), the control value of the compressor discharge pressure is reduced to suppress the blowout 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 / cm2G. At this time, the blowing temperature is about 45 ° C.
At the time of temperature control, the duty ratio may be appropriately adjusted so that the compressor discharge pressure corresponds to a desired blowing temperature.

In the duty control of the water valve 32, the water valve 32 is closed (OF
F) Even if the hot water flow rate to the sub-evaporator 8 is set to zero (0), if the blow-out temperature at that time is higher than a desired target temperature, the compressor 2 is turned off and blow-off is performed as a second stage control. Reducing the temperature is as described above.

Therefore, according to the first control method, it is possible to adjust the blow-out temperature (temperature control).
The duty control of the water valve 32 makes it possible to keep the fluctuations in the amount of heat absorbed and the cycle pressure / temperature within a certain range, thereby reducing the hunting of the blowout temperature during temperature control.

Next, the second control method will be described.

Here, as the control of the first stage, the blow-off temperature control is performed by ON / OFF control of the water valve 32 by the compressor discharge pressure. At this time, opening / closing (ON / OFF) of the water valve 32 is performed in a control range including an upper limit and a lower limit related to the compressor discharge pressure. Thereafter, even if the water valve 32 is closed and the flow rate of hot water to the sub-evaporator 8 is zero (0), if the blow-out temperature is equal to or higher than a predetermined temperature, as a second-stage control, the compressor 2 is turned off and blow-out is performed. Decrease temperature.

The details of the control of the first stage are as follows. Here, the amount of heat absorbed 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 reducing the blowout temperature. Control. More specifically, the water valve 32 is turned on / off within a control range preset according to the desired heating capacity with respect to the compressor discharge pressure (Pd).

For example, as shown in FIG. 6, when the compressor discharge pressure becomes equal to or higher than the upper limit Pd1 in a state where the water valve 32 is turned on, the water valve 32 is closed (O
FF), the water valve 32 is opened (ON) when it becomes lower than the lower limit value Pd2 in the OFF state. When the water valve 32 is opened (ON), the amount of heat absorbed by the sub-evaporator 8 increases with time because hot water is introduced into the sub-evaporator 8, and the compressor discharge pressure also increases. However, when the water valve 32 is closed (OFF). ), Since hot water is not introduced into the sub-evaporator 8, the amount of heat absorbed by the sub-evaporator 8 decreases with time, so that the compressor discharge pressure also decreases. Therefore, by appropriately setting the ON / OFF switching timing of the water valve 32, the amount of heat absorbed by the sub-evaporator 8,
Eventually, the compressor discharge pressure (Pd) and the blow-out temperature can be adjusted to certain levels (ranges).

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 control values (Pd1, Pd1
Set d2) high to increase the blowing temperature. For example, the control range of the compressor discharge pressure (Pd) is 17 to 20 kg.
/ cm2G and the water valve 32
N / OFF. At this time, the blowing temperature is about 55 ° C. Next, when the maximum heating capacity is not required, such as at the time of temperature control (when the heating operation is stable), the control value (Pd1, Pd2) of the upper and lower limits of the compressor discharge pressure is reduced to suppress the blowout temperature. For example, the control range of the compressor discharge pressure (Pd) is reduced to 15 to 17 kg / cm2G, and the water valve 32 is turned ON / OFF in this range. At this time, the blowing temperature is about 45 ° C. At the time of temperature control, the control range may be appropriately changed so that the compressor discharge pressure corresponds to a desired blowing temperature.

ON / O of the water valve 32
In the switching control of the FF, even when 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), if the blow-out temperature at that time is higher than a target desired temperature, As described above, as a two-step control, the compressor 2 is turned off to lower the blow-out temperature.

Therefore, the blowing temperature can be adjusted (temperature controlled) also by the second control method.

According to the first and second control methods, both are controlled by the auto amplifier 50.
There are no new parts related to temperature control, and cost increases can be avoided.

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. A system in which an evaporator is provided to enable dehumidification and heating may be used.

Further, in the above-described embodiment, a dual car air conditioner capable of heating both front and rear seats has been described as an example. However, the present invention is not limited to this.
The present invention can be applied to any type of heat pump type air conditioner for automobiles including a sub-evaporator, including a single type heat pump system. Therefore, it is not always necessary to provide both a sub-condenser and a heater core as a heating heat source in one unit as in the above-described embodiment.

[0061]

As described above, according to the first aspect of the present invention, the ON / OFF of the opening / closing means is controlled so that the compressor discharge pressure has a predetermined control value corresponding to a desired heating capacity.
Since the duty ratio of F is adjusted, the amount of heat absorption in the outdoor evaporator is adjusted, and the blowout temperature can be adjusted.

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 a desired heating capacity by the compressor discharge pressure, the amount of heat absorbed in the outdoor evaporator is adjusted, and the blowout temperature is adjusted. Can be adjusted.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, even if the hot water flow rate to the outdoor evaporator is set to zero, when the blowing temperature is equal to or higher than a predetermined value, the compressor is started. Since it is turned off, 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 type air conditioner for a vehicle 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 a heat absorption amount.

FIG. 4 is a table 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 same 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-condenser (indoor condenser) 14 ... Evaporator 17 ... Suction temperature sensor (outlet temperature detection means) 20 ... Rear unit 22 ... Rear sub-condenser 32 ... Water valve (opening / closing means) 50 ... Autoamplifier (control means) 53 ... Discharge pressure sensor (discharge pressure detecting means)

Claims (3)

[Claims] 1. A method for heating the interior of a vehicle cabin by utilizing the heat of a refrigerant circulating while changing the state of the inside of a refrigeration cycle, wherein the refrigeration cycle returns to a compressor (2) by heat exchange with engine cooling water. In a heat pump type automotive air conditioner provided with an outdoor evaporator (8) for heating a refrigerant, an opening / closing means (32) for opening and closing a passage for introducing engine cooling water to the outdoor evaporator (8); (2) a discharge pressure detecting means (53) for detecting the pressure of the refrigerant discharged from, so that the output of the discharge pressure detecting means (53) is a control value set in advance according to a desired heating capacity. Control means (5) for adjusting the ON / OFF time ratio of the opening / closing means (32).
0) and a heat pump type air conditioner for a vehicle, comprising: 2. A method for heating the interior of a vehicle cabin by utilizing the heat of a refrigerant circulating while changing the state of the inside of a refrigeration cycle, and returns to the compressor (2) by exchanging heat with engine cooling water to the refrigeration cycle. In a heat pump type automotive air conditioner provided with an outdoor evaporator (8) for heating a refrigerant, an opening / closing means (32) for opening and closing a passage for introducing engine cooling water to the outdoor evaporator (8); (2) discharge pressure detecting means (53) for detecting the pressure of the refrigerant discharged from the, the opening and closing means in a control range preset according to the desired heating capacity by the output of the discharge pressure detecting means (53)
A heat pump type air conditioner for a vehicle, comprising: control means (50) for controlling ON / OFF of (32). 3. An indoor condenser (13) provided in the refrigeration cycle and heating intake air by heat exchange with a refrigerant;
Blow-out temperature detecting means (17) for detecting the temperature of the air heated by passing through the indoor condenser (13), and the control means (50) controls the outdoor evaporator by the opening / closing means (32). The compressor (2) is turned off when the output of the blow-out temperature detecting means (17) is equal to or higher than a predetermined value when the introduction of the engine cooling water to the engine is stopped. 4. The heat pump type air conditioner for a vehicle according to 4.