JPH0789328A - Air-conditioning device for vehicle - Google Patents

Abstract

PURPOSE:To bring the body-feeling temperature to a set temperature, in an air- conditioning device for a vehicle in which when the thermal load is small, the cooling capacity of a compressor is restrained for saving fuel consumption, by correcting the setting temperature to a lower value as the degree of cooling of an evaporator becomes lower for decreasing the blowing air temperature. CONSTITUTION:Temperature regulation is carried out by forcedly feeding a coolant into an evaporator 4 through a compressor 2, and by exchanging heat between the coolant and the blowing air for cooling the flowing air, and by heating the cooling air while regulating the air flow rate being introduced into a heater unit 10 by means of an air-mix door 11. The air-conditioning device for a vehicle is provided with a temperature-setting means 48, a detecting means 46 for detecting the degree of cooling in the evaporator 4, a temperature correcting means 40A for correcting the setting temperature to a lower value as the degree of cooling becomes lower, and an opening control means 40B for controlling the opening of the air-mix door 11 on the basis of at least the setting temperature after correction and the degree of cooling of the evaporator. Even if the degree of cooling of the evaporator changes, the difference in the body-feeling temperature by the same setting temperature is restrained, and comfortable air conditioning can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner.

[0002]

2. Description of the Related Art In a vehicle air conditioner disclosed in, for example, Japanese Patent Laid-Open No. 2-290714, a compressor for a compression refrigeration cycle including a variable displacement compressor driven by an engine, a condenser, an evaporator, a liquid tank, and an expansion valve. A cold air is created by exchanging heat between the refrigerant and the air blown to the air conditioner with an evaporator. A heater unit is provided downstream of the evaporator to reheat the cool air from the evaporator to blow the air of a desired temperature into the vehicle. In an air conditioner equipped with this type of variable displacement compressor, when the heat load is not so large from the viewpoint of fuel efficiency, the displacement volume of the compressor is reduced and the cooling temperature in the evaporator is set to a high temperature, and the air mix door is set. Is controlled on the cool side.

[0003]

However, when the cooling temperature in the evaporator reaches, for example, about 15 ° C., the relative humidity becomes high, and even if the vehicle interior temperature is controlled to the set temperature, it feels slightly higher. I will end up. FIG. 10 is a graph in which temperature is plotted on the horizontal axis and relative humidity is plotted on the vertical axis, and it is shown that the relative humidity varies depending on the cooling condition in the evaporator even when the set temperature is 25 ° C. Point A indicates that the relative humidity is 30% when the evaporator is cooled to 3 ° C. by maximizing the cooling capacity of the variable displacement compressor. When the heat load is not so great like in spring or autumn,
From the viewpoint of fuel efficiency, the displacement volume of the compressor is reduced and the cooling capacity is small. For example, when the evaporator cools the air only up to about 15 ° C, the temperature inside the passenger compartment is set to 2
Even at 5 ° C, the relative humidity is as high as 60%, and it is felt as a high temperature. In FIG. 10, the hatched area is the temperature area where the passenger feels comfortable.

An object of the present invention is to provide an air conditioning system for a vehicle in which the sensible temperature can be felt at a set temperature even when the cooling capacity of the compressor is lowered.

[0005]

The present invention will be described with reference to FIG. 1, which is a diagram corresponding to claims. In the present invention, a compressor 2 pressure-feeds a refrigerant to an evaporator 4, and heat exchange is performed between the refrigerant and the blast air to generate blast air. It is applied to a vehicle air conditioner that cools and controls the temperature by heating the cooling air while controlling the flow rate of air introduced into the heater unit 10 by the air mix door 11. For the above-mentioned purpose, the temperature setting means 48 for inputting the set temperature in the vehicle interior and the evaporator 4 are used.
Detecting means 46 for detecting the degree of cooling at the temperature of the evaporator, and temperature correcting means 4 for correcting the set temperature so that the lower the cooling degree is, the lower the temperature is, depending on the detected cooling degree of the evaporator.
0A and at least opening control means 40B for controlling the opening of the air mix door 11 based on the corrected set temperature and the degree of cooling of the evaporator,
To be achieved. As the compressor 2, a variable displacement compressor whose displacement volume is variable according to heat load or vehicle operating condition, or an operation rate control type compressor whose discharge flow rate is adjusted according to heat load or vehicle operating condition is used. It is possible to provide the compressor control means 40C that reduces the flow rate of the refrigerant to reduce the degree of cooling in the evaporator 4 at least when the heat load is small.

[0006]

The degree of cooling in the evaporator 4 is detected by the detecting means 46.
Detected in. The temperature correction means 40A corrects the set temperature so that the lower the detected cooling degree of the evaporator, the lower the set temperature. The opening degree of the air mix door 11, that is, the flow rate of the air introduced into the heater unit 10 is adjusted based on the corrected set temperature and the degree of cooling of the evaporator. The lower the post-correction set temperature, the more air mix door 1
No. 1 reduces the amount of reheat to the heater unit 10, and the blowout temperature is reduced.

In the description of the means and action for solving the above problems for explaining the structure of the present invention, some of the reference numerals of the embodiments are used to make the present invention easy to understand. Is not limited to the embodiment.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. In one embodiment of the vehicle air conditioner according to the present invention, FIG.
As shown in (1), a cooler unit 100 for a compression refrigeration cycle including a variable displacement compressor 2, a condenser 3, an evaporator 4, a liquid tank 5, and an expansion valve 6 driven by an engine 1 is provided. The variable displacement compressor 2 increases the inclination angle to increase the discharge capacity when the suction pressure exceeds the set pressure, and the set pressure is controlled by the solenoid current Isol supplied from the control circuit 40 shown in FIG. To be done. Also evaporator 4
Is disposed in an air conditioning duct 7 having an outside air introduction port 7a and an inside air introduction port 7b.

Each of the inlets 7a and 7b is provided with an inside / outside air switching door 8 for controlling a flow rate of air introduced into the air conditioning duct 7. Further, as is well known, a blower fan 9, a heater unit 10, and an air mix door 11 are provided in the air conditioning duct 5, and the blowout amounts from the vent outlet 7c and the foot outlet 7d provided in the air conditioning duct 7 are respectively set. Adjusting vent door 12, foot door 13
Is provided. Further, a defroster door 14 is provided at the defroster outlet 7e provided in the air conditioning duct 7.

FIG. 3 shows an example of the control circuit 40 of the vehicle air conditioner according to the present invention. An outside air temperature sensor 43 for detecting the outside air temperature Tamb via the input circuit 42 to the CPU 41,
An indoor temperature sensor 44 for detecting a vehicle interior temperature Tinc, a solar radiation sensor 45 for detecting a solar radiation amount Qsun, an intake temperature sensor 46 for detecting an air temperature (hereinafter referred to as an intake temperature) Tint downstream of the evaporator 4, and an opening of the air mix door 11. The air mix door opening sensor 47 for detecting the temperature is connected to each of the sensors, and various temperature information and heat quantity information are input to the CPU 41 from these sensors 43 to 47. In addition, the input circuit 42
Includes an economy switch 51, an auto switch 52,
Blower fan switch 53, defroster switch 54,
Each temperature setting dial 48 is connected. The temperature setting dial 48 is a switch for an occupant to input a desired temperature.

Further, the CPU 41 is connected via an output circuit 49 to various door actuator groups 61 including an intake actuator and an aeromic door actuator, and a blower fan control circuit 62. The blower fan control circuit 62 is connected to the blower fan. The motor 9 is connected. The output circuit 49 is also connected via a relay 63 to a solenoid section 64 of an electromagnetic actuator that controls the compressor discharge capacity.

The CPU 41 drives and controls various actuators based on various information input from the respective sensors 43 to 47, the temperature setting dial 48 and the respective switches 51 to 54 to control the air inlet, outlet, outlet temperature, Properly control the blower fan air volume and compressor discharge capacity. In this embodiment, the economy switch 51
Is turned on under a heat load condition that does not require cold air from the compressor, and automatically controls the air outlet, the air flow rate, and the air temperature according to the heat load state while the compressor is off. Further, when the auto switch 52 is turned on,
Depending on the heat load, the compressor on / off control, outlet, outlet air volume, outlet temperature, etc. are automatically controlled.

Next, the operation of the embodiment will be described. Figure 4 is CP
It is a flow chart which shows basic control of an air-conditioning control device performed by U41. In step S10, initialization is performed, and in the normal auto air conditioner mode, for example, the set temperature Tptc is initialized to 25 ° C. Step S20
Then, input various information from each sensor.

The data information of each of these sensors will be specifically described. The set temperature Tptc is from the temperature setting dial 48, the vehicle interior temperature Tinc is from the indoor temperature sensor 44, the outside air temperature Tamb is from the outside air temperature sensor 43, and the suction temperature is. Tint is the intake temperature sensor 46, and the solar radiation amount Qsun is the solar radiation sensor 45.
From each.

Next, in step S30, the outside air temperature sensor 4
The outside air temperature Tamb obtained from No. 3 is processed to a value Tam corresponding to the actual outside air temperature by removing influences from other heat sources. Next, in step S40, the solar radiation amount information as the light amount from the solar radiation sensor 45 is processed into a value Qsun 'as a heat amount suitable for the subsequent conversion. In step S50, the set temperature Tptc set by the temperature setting dial 48 is processed into a value Tptc 'corrected as described below according to the outside air temperature Tamb and the suction temperature Tint downstream of the evaporator. Step S6
At 0, the target outlet temperature To is calculated from Tptc ', Tinc, Tam, Qsun', and the opening degree of the air mix door 11 is calculated according to the deviation between the target outlet temperature To and the actual outlet temperature. In step S70, the compressor 2 is controlled as described below. In step S80, each outlet is controlled. In step S90, selective switching of the suction port, that is, the outside air introduction port 7a and the inside air introduction port 7b is controlled. In step S100, the blower fan 9 is controlled to control the air volume from the air outlet.

FIG. 5 shows the set temperature correction control of FIG. 4 (step S
50) is a flow chart for explaining (50) in detail. In step S51, the correction coefficient α increases as the outside air temperature Tamb increases.
Is set small, and in step S52, the suction temperature Tin
The higher t is, the smaller the correction coefficient β is set. Step S
At 53, the set temperature Tptc is corrected by the correction coefficients α and β to calculate the corrected set temperature Tptc ′. Corrected outside air temperature Tam
The correction coefficients α and β may be determined based on Even if the set temperature is corrected, the panel display temperature is not changed.

FIG. 6 is a flow chart for explaining the air mix door opening calculation control (step S60) of FIG. 4 in detail. In step S61, the constants A to G are initialized, and in step S62, the current air mix door opening X is input by the signal of the air mix door opening sensor 47. Next, in step S63, the deviation S between the target blow temperature To and the actual blow temperature is obtained based on the equation (1).

[0018]

## EQU1 ## S = (A + D) Tptc '+ BTam + CQsun'-DTinc + E- (FX + G) (82-Tint) -Tint (1) where (A + D) Tptc' + BTam + CQsun'-DTinc
+ E is the target outlet temperature To, (FX + G) (82-Tint)
-Tint corresponds to the actual blowing temperature.

Then, in step S64, the deviation S
Is compared with a predetermined value So. If S <-So, the air mix door opening is set to the cold side, that is, to the close side so that the flow rate of the air passing through the heater unit 10 is reduced in step S65. If S> + So, step S66
The air mix door opening is set to the hot side, that is, to the open side so that the flow rate of air passing through the heater unit 10 increases. If S ≦ ± So, the current opening is maintained as it is in step S67.

FIG. 7 is a flow chart for explaining the compressor control (step S70) of FIG. 4 in detail. Figure 7
In step S71, it is determined whether or not the blower fan 9 is operating (ON) by a signal from the economy switch 51, the auto switch 52, or the blower fan switch 53. If the blower fan 9 is not operating, the compressor 2 is operated in step S77. Stop (off). If it is operating, in step S72, the defroster switch 54
Is turned on, and if it is turned off, step S
Proceeding to 73, it is determined whether or not the economy switch 51 is turned on. If the economy switch 51 is on, the compressor 2 is stopped in step S77, and if it is off, the process proceeds to step S74, and it is determined whether or not the auto switch 52 is on. If the defroster switch 54 is on, steps S73 and S74 are skipped and the process proceeds to step S75.

When the auto switch 52 is determined to be off in step S74, the compressor is stopped in step S77. When it is determined in step S74 that the auto switch 52 is on, the process proceeds to step S75, and the corrected outside air temperature T
States 1 to 3 are determined based on am, and in step S76, steps S77 and
Proceed to S78A and S79. Outside temperature Tam as in state 1
If is low (for example, minus several degrees), step S7
If the outside air temperature Tam is high as in state 3 (for example, plus tens of degrees) as in state 3, the process proceeds to step S79, and the compressor 2 is operated at the maximum displacement volume. If the state 2 is determined, the process proceeds to step S78A,
The target suction temperature Tint 'is calculated based on the target outlet temperature To according to the characteristic diagram shown. Step S7
At 8B, the solenoid current Isol for controlling the capacity of the variable capacity compressor 2 is obtained.

FIG. 8 is a diagram showing a procedure for calculating the solenoid current Isol. First, in step S781, the suction temperature Tin
The difference (Tint−Tint ′) between t and the target suction temperature Tint ′ is calculated, and the proportional term current I _P and the integral term current I _I are calculated from this difference in accordance with FIGS. 9A and 9B, respectively, in step S78.
Find in 2. Here, the proportional term current I _P is calculated in step S78.
Based on the difference calculated in 1, it is obtained from FIG. 9 (b),
Integral term current I _I, based on the same difference obtains a [Delta] I _I from FIG. 8 (a), the value I _I plus I _I up to the previous to this [Delta] I _I
It is calculated as (= I _I + ΔI _I ). And step S
At 783, a current corresponding to the difference between the proportional term current I _P and the integral term current I _I is obtained as the solenoid current Isol.
That is, the solenoid current Isol is

[0023]

## EQU2 ## Isol = I _P −I _I (2) However, I _P is ampere and I _I is milliampere.

As can be seen from the equations (a), (b) and (2) of FIG. 9, the actual suction temperature Tint is the target suction temperature Tint '.
When it is larger, the solenoid current Isol is smaller and the compressor discharge capacity is larger (cooling capacity is larger).

By controlling the compressor so that the suction temperature Tint corresponds to the target outlet temperature To, the fuel consumption and the power consumption can be reduced for the following reasons. When the opening of the air mix door 11 is adjusted to obtain a desired outlet temperature by the deviation between the current inlet temperature Tint and the target outlet temperature To, the inlet temperature Tint depends on the operating state.
May undesirably become too low. In this case, the air mix door 11 is opened slightly to control the blowout temperature to a target value. Therefore, the compressor wastes power and adversely affects fuel consumption.

According to this embodiment, a certain target outlet temperature T
With respect to o, the temperature of the air downstream of the evaporator 4, that is, the suction temperature Tint, should be determined as an experimental value in order to obtain that temperature, and the target blowout temperature To is changed to the target suction temperature Tint ′. Step S78A in FIG.
The target discharge temperature Tint 'is used to control the discharge capacity of the compressor, and the suction temperature Tint' is determined.
I try not to make it drop too much. This means that the compressor is operated with the minimum necessary discharge capacity (tilt angle), and therefore the absorption horsepower is also reduced, which contributes to power saving and fuel saving.

According to such an embodiment, the suction temperature T
The higher the int, the smaller the correction set temperature Tptc ', the lower the target blowout temperature To, and the air mix door 11 is closed on the cool side, so the blowout temperature drops. As a result, the temperature inside the vehicle is set slightly lower than the set temperature (for example, a few degrees lower), and the sensible temperature does not increase even if the relative humidity increases due to the higher cooling temperature in the evaporator. That is, the suction temperature Tint depends on the cooling capacity of the compressor 2, and when the temperature is relatively low such as spring and autumn, the compressor discharge capacity is controlled to be small, the cooling degree in the evaporator is reduced, and the relative humidity is increased, By setting the inside of the vehicle to be several degrees lower than the set temperature, it is possible to prevent the sensible temperature from increasing.

FIG. 10 illustrates this situation. When the set temperature is 25 ° C., the suction temperature Tint is 3 ° C., the relative humidity is 30%, and the suction temperature Tint is 15%.
When the temperature reaches ℃, the relative humidity rises to 60% and is located at point B,
The sensible temperature rises and falls outside the range of comfort. Therefore, as in the embodiment, by correcting the set temperature from, for example, 25 ° C. to 23.6 ° C. and lowering the blowing temperature, it is possible to operate at point C within the comfort range.

Further, in the above embodiment, the target intake temperature Tint 'is determined according to the target outlet temperature To, and the discharge capacity of the compressor is controlled by the difference between the actual intake temperature Tint and the target intake temperature Tint'. Since the target blowing temperature To is set to Step S78A in FIG.
When it is between T50 and T51, the discharge capacity of the compressor is inevitably increased, the degree of cooling in the evaporator is improved, and the relative humidity is controlled to be low.

Although an air conditioner using a variable capacity compressor has been described above, the present invention can also be applied to an air conditioner of a system in which a fixed capacity compressor is turned on / off to control an operating rate.

[0031]

As described above in detail, according to the present invention, in an air conditioner that suppresses the cooling capacity of the compressor to save fuel consumption when the heat load is small, the set temperature is lowered as the cooling degree of the evaporator is lower. Since the blow-out temperature is lowered by correcting the above, the difference in sensible temperature due to the same set temperature can be suppressed even if the degree of cooling in the evaporator changes, and comfortable air conditioning can be performed while achieving fuel efficiency.

[Brief description of drawings]

[Fig.1] Claim correspondence diagram

FIG. 2 is a configuration diagram of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 3 is a block diagram showing a control circuit of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 4 is a basic flowchart of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 5 is a flowchart of a set temperature correction control of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 6 is a flowchart of air mix door opening control of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 7 is a flow chart of compressor control of an embodiment of a vehicle air conditioner according to the present invention.

FIG. 8 is a flowchart of solenoid current calculation control of one embodiment of the vehicle air conditioner according to the present invention.

9 is a graph illustrating calculation of solenoid current in FIG.

FIG. 10 is a graph illustrating the relationship between relative humidity and sensible temperature.

[Explanation of symbols]

 2 Compressor 4 Evaporator 11 Air mix door 40 Control circuit 40A Temperature correction means 40B Opening control means 40C Compressor control means 46 Suction temperature sensor 47 Air mix door opening sensor 48 Temperature setting dial 61 Door actuator group

Claims (2)

[Claims] 1. A compressor sends a refrigerant under pressure to an evaporator to exchange heat between the refrigerant and blast air to cool the blast air, and at the same time adjust an air flow rate introduced into a heater unit by an air mix door. In a vehicle air conditioner that heats cooling air to adjust the temperature, temperature setting means for inputting a set temperature in a vehicle compartment, detection means for detecting a degree of cooling in the evaporator, and degree of cooling of the detected evaporator. Temperature correction means for correcting the set temperature so that the cooling degree becomes lower as the cooling degree decreases, and the opening of the air mix door is based on at least the corrected set temperature and the cooling degree of the evaporator. An air conditioner for a vehicle, comprising: an opening degree control unit that controls the degree. 2. The air conditioner according to claim 1, wherein the compressor has a variable displacement compressor whose displacement volume is variable according to a heat load or a vehicle operating state, or a discharge according to a heat load or a vehicle operating state. An air conditioner for a vehicle, which is an operation rate control type compressor in which a flow rate is adjusted, and which is provided with compressor control means for reducing the flow rate of the refrigerant to reduce the degree of cooling in the evaporator at least when the heat load is small. .