JPH09295507A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the control responsiveness in such a manner that the car compartment temperature quickly reaches a desired temperature by operating in such a manner that the radiator temperature or the radiator outlet air temperature reaches a designated radiator target temperature or a designated radiator outlet air target temperature higher than the target blowout temperature. SOLUTION: Brine which is forced to reach a high temperature by heat exchange in a heat exchanger 5 is heat-exchanged with the interior air by a radiating pipe 4 to heat the interior of a car compartment. The target blowout temperature from an air duct 18 is operated by a target blowout temperature operating means. The control position of an air mix damper 28 is operated by a quantity of airflow rate operating means according to the target blowout temperature, the radiator temperature or the radiator outlet air temperature and the radiator inlet air temperature. The quantity of airflow rate of the radiator 4 is controlled to control the blowout temperature, so that the responsiveness of the blowout temperature is quick.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vehicle air conditioner having at least a heating function.

[0002]

2. Description of the Related Art Conventionally, there has been known a vehicle air conditioner having at least a heating function and having a configuration common to that of the present invention to be described later. For example, as shown in FIG. 1, a compressor 1 whose discharge capacity is variable, an outdoor heat exchanger 2, a brine-refrigerant heat exchanger 5, and a radiator 4 provided in a ventilation duct 18 are provided. Vehicle air conditioners are known. An ethylene glycol aqueous solution is used as the brine, and HFC134a is used as the refrigerant.

In the conventional control of such a vehicle air conditioner, in the heating operation, the airflow rate (passage rate) of the radiator 4 is maximized, and the radiator outlet air temperature or the radiator temperature is increased. The discharge capacity of the compressor was controlled so as to reach the target blowout temperature.

For example, as shown in FIG. 6, the vehicle interior temperature Tr detected by the vehicle interior sensor, the outside air temperature Tam detected by the outside air sensor, the amount of solar radiation Tst detected by the solar radiation sensor, and the vehicle interior set temperature set by the setting device. The target outlet temperature TAO is calculated by the following equation based on Ts,
Based on O and the water temperature TW detected by the water temperature sensor 17 as the radiator temperature, the compressor 1 is calculated by the following equation, for example.
The rotation speed Nc of is calculated.

TAO = Ks.multidot.Ts-Kr.multidot.Tr-Kam.multidot.
Tam−Kst · Tst + C Nc = P (P component in PI control) + I (same I component) = − Kpc (TW-TAO) + I _n where I _n = I _n−1 −G · Kpc · Δt / Ki · ( TW-TA
O) Here, Ks, Kr, Kam, and Kst are coefficients, C is a correction constant, Kpc is a basic gain in the Nc calculation formula, G is the same correction gain, and Δt is an output change period in the Nc calculation formula,
Ki indicates the integration time in the Nc arithmetic expression, respectively.

The water temperature sensor temperature TW is detected as the radiator temperature. This TW may be replaced with the exhalation sensor temperature TO.

[0007]

However, in the system, which is generally said to have slow response, as described above, the response of the radiator temperature or the radiator outlet air temperature due to the change of the discharge capacity of the compressor is slow. Therefore, even if the occupant changes the temperature setting, it takes a long time for the discharge temperature and eventually the vehicle interior temperature to reach a desired temperature, and it is difficult to obtain a comfortable temperature control state.

For example, as shown in FIG. 7, the set temperature Ts
The actual blowout temperature (in this case, ≈TW) when is changed
There is a problem that it takes a long time for the vehicle interior temperature Tr to reach the target value.

Therefore, an object of the present invention is to control the radiator air flow rate and to control the compressor discharge capacity so that the radiator temperature is higher than the target outlet temperature, especially during heating. The purpose is to improve the control responsiveness so that the actual blow-out temperature and thus the vehicle interior temperature can reach the desired temperature more quickly.

[0010]

In order to solve the above problems, a vehicle air conditioner according to the present invention comprises at least a compressor having a variable discharge capacity and a radiator provided in a ventilation duct. A refrigerant circuit capable of heating operation, and a radiator temperature detecting means for substantially detecting the temperature of the radiator,
A vehicle air conditioner comprising a ventilation amount ratio changing means capable of changing a ratio between the amount of air passing through the radiator and the amount of air bypassing the radiator, the control of the ventilation amount changing means. The amount is calculated by the ventilation amount calculation means based on at least the radiator temperature or the radiator outlet air temperature, the radiator inlet air temperature, and the target outlet temperature from the ventilation duct, and the discharge capacity is calculated. The variable control amount of the compressor becomes a predetermined radiator target temperature or radiator outlet air target temperature in which the radiator temperature or the radiator outlet air temperature is higher than the target outlet temperature by the compressor output calculation means. It is characterized by being calculated as follows.

It is preferable that the vehicle air conditioner includes an outside air temperature detecting means, and the radiator target temperature or the radiator outlet air target temperature is calculated based on at least the outside air temperature detected by the means. Further, a vehicle interior temperature detecting means may be further provided, and the radiator target temperature or the radiator outlet air target temperature may be calculated based on at least the vehicle interior temperature detected by the means and the outside air temperature. .

Further, the radiator inlet air temperature detecting means or the radiator inlet air temperature estimating means is provided, and at least the radiator inlet air temperature, the radiator temperature, the voltage of the blower provided in the ventilation duct, and the current ventilation. The radiator outlet air temperature may be estimated based on the amount.

In such a vehicle air conditioner, since the blowout temperature is controlled by adjusting the control amount of the air flow rate varying means, the response of the blowout temperature at the time of changing the setting is fast, and by extension the response of the temperature inside the vehicle. Sex also becomes faster. Then, the discharge capacity of the compressor is controlled so that the radiator temperature or the radiator outlet air becomes a target value that is higher than the target outlet temperature, so that the discharge temperature and thus the vehicle interior temperature are changed to a higher temperature. Even in the case of a problem, quick response can be expected.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a device arrangement and a configuration of a refrigerant circuit according to an embodiment of the present invention. In FIG. 1, 1 is a variable capacity electric compressor, 2 is an outdoor heat exchanger, 3 is an indoor heat absorber provided in a ventilation duct 18, 4 is an indoor radiator, and 5 is a brine-refrigerant (for example, ethylene glycol). Aqueous solution to HFC134a) heat exchangers are shown respectively. 6 and 7 are expansion valves, 8 and 9,
10, 11 are circuit switching solenoid valves, 12 and 13 are check valves,
Reference numeral 14 is a receiver tank, 15 is an accumulator, 16 is a pump for circulating brine, 17 is a water temperature (brine temperature) sensor, and the temperature detected by the water temperature sensor 17 substantially indicates the temperature of the radiator 4. , Functions as a radiator temperature detecting means.

Reference numeral 19 is an outside air intake port, 20 is an inside air intake port, 2
1 is a switching damper for an inlet, 22 is a vent outlet, and 23
Is a foot outlet, 24 is a differential outlet, 25 is an opening / closing damper for a vent outlet, 26 is an opening / closing damper for a foot outlet, 27 is an opening / closing damper for a differential outlet, and 28 is a radiator 4.
Air mix damper as a means for changing the air flow rate of 2
A blower 9 sucks air into the ventilation duct 18 and exhausts air from the duct 18. Reference numeral 40 denotes a temperature sensor capable of detecting the outlet side air temperature of the heat absorber 3, and thus the inlet side air temperature of the radiator 4.

The brine, which has become hot due to the heat exchange in the heat exchanger 5, is heat-exchanged with the indoor air in the radiator 4 to heat the interior of the vehicle.

In such a vehicle air conditioner, the control according to the present invention is performed as shown in FIGS. 2 and 3, for example. First, the control of the air flow rate varying means, that is, the position (opening) control of the air mix damper 28 is performed as follows. As shown in FIG. 2, the target outlet temperature calculation means 31
Thus, the target outlet temperature from the ventilation duct 18 is calculated. This calculation is performed based on at least the vehicle interior temperature Tr detected by the vehicle interior sensor, the outside air temperature Tam detected by the outside air sensor, and the set value Ts of the vehicle interior temperature. In the present embodiment, the solar radiation detected by the solar radiation sensor is further included. Quantity T
st has been added. The target outlet temperature TAO is calculated, for example, by the following equation. TAO = Ks-Ts-Kr-Tr-Kam-Tam-Kst-
Tst + C Here, Ks, Kr, Kam, and Kst are coefficients, and C is a correction constant. Up to this point, the calculation is substantially the same as the conventional calculation shown in FIG.

Then, at least the target outlet temperature T
AO and radiator temperature or radiator outlet air temperature TO,
Based on the radiator inlet air temperature Tin, the control position SW of the air mix damper 28 is calculated by the ventilation amount ratio calculation means 32, for example, by the following equation. SW = (TAO-Tin) / (TO-Tin)

When the radiator temperature is used as TO here, the water temperature sensor temperature TW can be used directly, or the outlet or inlet of the radiator 4, the hot water temperature inside, or the outlet or inlet of the radiator 4. It is also possible to detect the pipe surface temperature inside, and further the temperature between the fins of the radiator 4, and use this detected temperature.

Further, when the radiator outlet air temperature is used as TO, in the present embodiment, the TO can be estimated by the following equation, for example. TO = f (Tin, BLV, current SW, TW) = TW + K ₁₂ · BLV · current SW + K ₁₃ · Tin + C ₅ where BLV is the blower voltage, K ₁₂ and K ₁₃ are coefficients, and Tin
Is an estimated radiator inlet temperature, for example, Tin = Tam for outside air introduction, Tin = Tr for inside air introduction, and Tin = (Tam + Tr) / 2 for intermediate position.

Further, the coefficients K ₁₂ and K ₁₃ are determined by each design specification of the air conditioner, and the relationship between the design specification and each coefficient is as shown in Table 1, for example.

[0022]

[Table 1]

When the radiator outlet air temperature is used as the TO, the TO may detect the radiator outlet air temperature with a temperature sensor and use this detected temperature.

To control the discharge capacity of the compressor, the rotational speed Nc of the compressor is calculated as shown in FIG. 3, for example. First, the calculation means 33 calculates the radiator target temperature or the radiator outlet air target temperature TV. In this embodiment,
TV is calculated as the radiator target temperature, more specifically, the target brine temperature, that is, the target water temperature.
Then, the calculation of the radiator target temperature TV is performed by the outside air temperature T
It is based on am. This radiator target temperature is calculated as a temperature higher than the above-mentioned target outlet temperature TAO.

This calculation is performed, for example, by the following equation. TV = f (Tam) = -K 14 · Tam + C 6 wherein, K ₁₄ is a coefficient, C ₆ is a correction constant. And
The target water temperature upper limit TV so that the TV fits within a certain range
When it becomes larger than max, and the target water temperature lower limit T
When it becomes smaller than Vmin, it is preferable to set the following restrictions. That is, when TV> TVmax, TV = TVmax, and when TV <TVmin, TV = TVmax.
= TVmin

The radiator target temperature TV may be calculated by the calculating means 35 based on the outside air temperature Tam and the vehicle interior temperature Tr, as shown in FIG. In this case, for example, TV = f (Tam, Tr ) = is calculated by _{-K 15 · Tam-K 16 ·} T r + C 7. Here, K ₁₅ and K ₁₆ are coefficients, and C ₇ is a correction constant. Further, it is preferable to set the same restrictions as described above with respect to TVmax and TVmin.

The radiator target temperature T calculated as described above
Based on V and the water temperature sensor temperature TW, for example, the compressor output calculation means 34 calculates the rotation speed Nc of the compressor 1 to be controlled as follows. However, in the following calculation, it is possible to use the above-described estimated radiator outlet air temperature TO instead of the water temperature sensor temperature TW as the radiator temperature. It is also possible to use a radiator outlet air temperature sensor and use this detected temperature as TO.

Nc = −P (P component in PI control) + I (same I component) = − Kpc (TW-TV) + I _n However, I _n = I _n−1 −G · Kpc · Δt / Ki · (TW -TV) where Kpc is the basic gain in the Nc arithmetic expression, and G is N
The correction gain in the c calculation formula, .DELTA.t is the output (Nc) change cycle, and Ki is the integration time in the Nc calculation formula.

The number of revolutions of the compressor 1 is controlled based on Nc calculated in this way. In addition, as described above, FIG.
Since the ventilation amount ratio of the radiator 4 is controlled and the blowout temperature is controlled by the calculation shown in (1), the responsiveness of the blowout temperature is fast. Further, since the compressor rotation speed Nc is controlled so as to achieve the radiator target temperature TV that is higher than the target blowout temperature TAO, which is separately determined, even when the set temperature is changed to a higher temperature, the speed is promptly increased. The outlet temperature can reach the target value TAO. Therefore, the blowout temperature, and thus the vehicle interior temperature, can quickly reach the desired target temperature.

For example, an example of the control result in the above embodiment is shown in FIG. 5, but the control responsiveness is significantly improved as compared with the conventional example shown in FIG.

[0031]

As described above, according to the vehicle air conditioner of the present invention, the ventilation amount ratio varying means of the radiator is controlled and the radiator temperature becomes a target value higher than the target outlet temperature. Since the discharge capacity of the compressor is controlled, the responsiveness of the control can be greatly improved, and when the set temperature is changed, the blowout temperature and thus the vehicle interior temperature can quickly reach the desired temperature. it can.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner according to an embodiment of the present invention.

FIG. 2 is a control block diagram of a ventilation amount ratio varying unit in the apparatus of FIG.

3 is a control block diagram of a compressor in the apparatus of FIG. 1. FIG.

FIG. 4 is a control block diagram showing a modification of the control of FIG.

FIG. 5 is a characteristic diagram showing an example of a result of the control of FIGS. 2 and 3.

FIG. 6 is a conventional control block diagram.

7 is a characteristic diagram showing an example of a result of the control of FIG.

[Explanation of symbols]

 1 Compressor 2 Outdoor heat exchanger 3 Heat absorber 4 Radiator 5 Brine-refrigerant heat exchanger 6,7 Expansion valve 8, 9, 10, 11 Solenoid valve 12, 13 Check valve 14 Receiver tank 15 Accumulator 16 Pump 17 Water temperature (Brine temperature) sensor 18 Ventilation duct 19 Outside air intake port 20 Inside air intake port 21 Switching damper 22, 23, 24 Outlet port 25, 26, 27 Opening / closing damper 28 Air mix damper as a ventilation amount varying means 29 Blower 31 Target outlet temperature calculation Means 32 Ventilation amount calculation means 33 Radiator target temperature calculation means 34 Compressor output calculation means 35 Radiator target temperature calculation means 40 Temperature sensor

Claims (4)

[Claims] 1. A refrigerant circuit including at least a compressor having a variable discharge capacity and a radiator provided in a ventilation duct, which enables a heating operation, and substantially detects the temperature of the radiator. A vehicle air conditioner comprising: a radiator temperature detecting means; and an air flow rate ratio varying means capable of varying a rate of air passing through the radiator and a rate of air bypassing the radiator. The control amount of the ventilation rate varying means is based on at least the radiator temperature or the radiator outlet air temperature, the radiator inlet air temperature, and the target blowout temperature from the ventilation duct by the ventilation rate computing means. The control amount of the compressor that is calculated and is capable of varying the discharge capacity is determined by the compressor output calculation means such that the radiator temperature or the radiator outlet air temperature is higher than the target outlet temperature. Or An air conditioner for a vehicle, which is calculated so as to reach a radiator outlet air target temperature. 2. The vehicle air conditioner according to claim 1, further comprising an outside air temperature detecting means, wherein the radiator target temperature or the radiator outlet air target temperature is calculated based on at least the outside air temperature detected by the means. 3. A vehicle interior temperature detecting means, at least:
The vehicle air conditioner according to claim 2, wherein the radiator target temperature or the radiator outlet air target temperature is calculated based on the vehicle interior temperature detected by the means and the outside air temperature. 4. A radiator inlet air temperature detecting means or a radiator inlet air temperature estimating means is provided, and at least the radiator inlet air temperature, the radiator temperature, the voltage of the blower provided in the ventilation duct, and the current ventilation. The vehicle air conditioner according to claim 1, wherein the radiator outlet air temperature is estimated based on the amount ratio.