JP3185161B2 - Automotive air conditioner control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for automobiles.
Air conditioners, more specifically, evaporators
And the sub-computer whose ventilation volume is adjusted by the mix door.
Distribute the compressor, compressor, main condenser, sub
Cycle with condenser, expansion valve and evaporator
The present invention relates to a control device for an air conditioner for a vehicle having a vehicle .

[0002]

2. Description of the Related Art Air conditioners for electric vehicles include:
For example, Japanese Unexamined Patent Publication No. 59-49439 and Japanese Utility Model Publication No.
Although it is conceivable to use a heat pump type air conditioner disclosed in Japanese Patent No. 8484 or the like, in recent years,
A sub-condenser is provided downstream of the cooling unit of the air conditioning duct, and by switching the three-way valve provided on the inflow side of the main condenser, the refrigerant flowing out of the compressor can be cooled in the cooling operation in the order of the main condenser, sub-condenser, cooling unit, and compressor. A system has been considered in which a main condenser is bypassed during a heating operation, and a sub-condenser, a cooling unit, and a compressor are circulated in this order. In this system, during the heating operation, the refrigerant discharged from the compressor is radiated by the sub-condenser in the same air-conditioning duct and is absorbed by the cooling unit. The air is heated.

[0003]

However, the above-mentioned system has an advantage that the heating operation can be continuously performed even in low outside air, but the air once cooled by the cooling unit is heated by the sub-condenser. Therefore, at the beginning of heating, since the intake air of the cooling unit is low, the outlet air temperature of the cooling unit is further reduced, and the temperature of the blown air supplied to the vehicle interior after being heated by the sub-condenser does not easily rise. However, the heating effect was poor.

In this case, the rotation speed of the compressor is increased,
The amount of heat radiation may be increased by increasing the energy input into the cycle. However, in this system, the amount of heat radiation increases by the amount of heat radiation, and there is a possibility that the evaporator freezes.

[0005] Therefore, in the present invention, to solve the above inconveniences, the braking of an automobile air conditioner excellent heating fast-acting to enhance the heating capacity while achieving antifreeze evaporator
It is an object to provide a control device .

[0006]

The inventor of the present invention has proposed that the above-mentioned new system gradually reduces the opening of the air mix door (reduces the amount of air flowing through the sub-condenser) as shown in FIG.
If the temperature of the evaporator and the sub-condenser increases, the temperature of the sub-condenser increases when the rotation speed of the compressor increases. On the other hand, the present invention has a qualitative characteristic that the blowing temperature of the evaporator is low while the temperature is high, and the present invention has been achieved.

That is, an air conditioner for a vehicle according to the present invention.
The gist of the control device is that environmental factor detecting means for detecting environmental factors inside and outside the vehicle interior, evaporator outlet temperature detecting means for detecting the actual outlet temperature of the evaporator, an evaporator in the air conditioning duct, and a mixed door. Arranging a sub-condenser whose ventilation amount is adjusted, a compressor, a main condenser, the sub-condenser, an expansion valve, and a cooling and heating cycle connecting at least the evaporator in this order,
The actual blow-out temperature of the evaporator detected by the evaporator blow-out temperature detecting means is inputted, and the target opening degree of the air mix door for bringing the actual blow-out temperature of the evaporator closer to the limit temperature at which the evaporator does not freeze is calculated. First control means for driving and controlling the air mix door based on the opening degree, and an output signal of the environmental factor detection means,
A target outlet temperature to be blown into the vehicle interior is calculated based on the output signal, a target discharge amount of the compressor is calculated so as to obtain the target outlet temperature, and a drive control of the compressor is performed based on the target discharge amount . 2 control means.

[0008]

Therefore, the first control means controls the opening of the air mix door so that the evaporator does not freeze, and the second control means discharges the compressor so that the required heating capacity is obtained. Since the amount is controlled, if the second control means sets the target outlet temperature in the vehicle compartment high, the discharge amount of the compressor increases.
Although the temperature of the evaporator may be lowered to cause the evaporator to freeze, the opening of the air mixing door is adjusted by the first control means to a limit temperature at which the evaporator does not freeze. The heating capacity can be increased without causing the heating.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an air conditioner according to the present invention. The air conditioner 1 is mounted on an electric vehicle, and an intake device 3 is provided at the most upstream side of an air conditioning duct 2. The opening ratio with the outside air inlet 5 is adjusted by an intake door 6 driven by an actuator 16. The air sucked by the rotation of the blower 7 through the intake device 3 is sent to the evaporator 8 and the sub-condenser 9, where the heat is exchanged. The sub capacitor 9
The mixing door 1 is disposed downstream of the evaporator 8 and determines the ratio of the air passing therethrough to the bypassing air.
The opening degree of 0 can be changed by adjusting the opening degree with the actuator 17.

The mixed door 10 is located at the α position indicated by the broken line at an opening of 0%, the air flow through the sub-condenser 9 is minimized, and is at the β position indicated by the solid line at the opening of 100%. The ventilation volume is at its maximum.

The most downstream side of the air conditioning duct 2 is divided into a defrost air outlet 11, a vent air outlet 12, and a heat air outlet 13, and opens into the vehicle compartment. The mode doors 15a, 15b, 15c The mode doors 15a, 15b, 15c are
, The blowout mode can be switched to the vent mode, the bilevel mode, and the heat mode.

The outflow side of the sub-condenser 9 is connected to the inflow side of the evaporator 8 via the liquid tank 20 and the expansion valve 21, and the outflow side of the evaporator 8 is connected to the suction side of the compressor 22 by piping. The discharge side of the compressor 22 is connected via a solenoid valve 23 to the inflow side of the main condenser 24.
Is connected to the inflow side of the sub-condenser 9 via a check valve 25. Further, a bypass passage 27 which is opened and closed by an electromagnetic valve 26 and bypasses the main condenser 24 is connected between the discharge side of the compressor 22 and the outflow side of the check valve 25 by piping.

By controlling the opening and closing of the solenoid valves 23 and 26, the refrigerant discharged from the compressor 22 is supplied to the main condenser 24, the check valve 25, the sub-condenser 9, the liquid tank 20, the expansion valve 21, and the evaporator 8 in this order. A first path that circulates, a sub-condenser 9, a liquid tank 20, and an expansion valve 2 that bypass the main condenser 24.
1. The evaporator 8 and the second path circulating in this order are switched.

Reference numeral 28 denotes an indoor temperature sensor for detecting the temperature in the vehicle interior; 29, an outside air temperature sensor for detecting the outside air temperature; and 30, an evaporator temperature sensor for detecting the blow-out temperature immediately after the evaporator 8, and output signals of these sensors. Is input to the control unit 33. This control unit 3
Reference numeral 3 denotes a central processing unit (CPU) (not shown), a read-only memory (ROM), and a random access memory (RA).
M), an input / output port (I / O) and the like. In addition to the output signals of the sensors 28 to 30, an output signal from a temperature setter 32 for setting a target temperature in the vehicle compartment is input. Each signal is processed according to a predetermined program, and a driving circuit 35, a motor 34 for driving the compressor 22, a motor for the blower 7, and actuators 16, 17, and 18 are provided.
Control signals are output through 36, 37, 38, and 39 to control the discharge capacity of the compressor 22, the rotation speed of the blower 7, the opening of the mix door 10, and the switching between the suction mode and the blowing mode. .

FIG. 2 is a functional block diagram showing an operation example of heating control by the control unit. The functional block diagram will be briefly described. Based on the blowing temperature (Te) of the evaporator 8, the difference (ΔTe) from the limit temperature (for example, 2 ° C.) at which the evaporator 8 does not freeze (ΔTe)
= 2 ° C-Te) (Block A), and the difference (ΔT
The target opening (） ′) of the mix door 10 is calculated based on e) (block B). Then, based on the target opening (Θ ′) and the actual opening (Θ) of the mixing door 10, the mixing door 10 is driven so that the actual opening (Θ) becomes the target opening (Θ ′) (block C). ). In addition, at least the outside air temperature (Ta), the vehicle interior temperature (Tr), and the set temperature (Tset)
Calculates the target outlet temperature (T _OF ') to be blown into the vehicle interior based on the target temperature (Block D), and calculates the target rotation speed of the compressor from the target outlet temperature (T _OF ') and the actual outlet temperature (T _OF ) in the vehicle interior. (Rpm ') is calculated (block E). Here, the actual outlet temperature (T _OF ) in the vehicle compartment is obtained by calculating the outlet temperature (Te) of the evaporator and the target rotation speed (rpm) of the compressor.
m ′) is presumed to be calculated (block F). Then, the compressor 22 is driven based on the target rotation speed (rpm ′) obtained in the block E (block G).

More specific control contents are shown as a flowchart in FIG. 3, and an example of the control operation will be described below with reference to this flowchart.

The control unit 33 starts the execution of this processing when the ignition switch is turned on.
In step 50, the target opening of the mix door 10 is set to 10%, and the target rotation speed of the compressor 22 is set to the minimum rotation speed (mi).
Initial settings such as n) are performed. Then, in step 52, signals from the various sensors 28 to 30 and the temperature setting device 32 are input.

In step 54, the evaporator 8
Is assumed to be, for example, 2 ° C., and the difference from the outlet temperature (Te) immediately after the evaporator 8 (ΔTe = 2 ° C.−T)
e) is calculated.

Thereafter, in step 56, it is determined whether or not the value of ΔTe is larger than a predetermined positive value, smaller than a predetermined negative value, or any other value.

Here, in the above system, FIG.
As shown in (2), if the opening degree of the mix door is reduced, the blowout temperature (Te) of the evaporator increases, so that the actual blowout temperature of the evaporator is lower than the freezing limit temperature (2 ° C.). In case, mixed door 10
The freezing of the evaporator 8 can be prevented by reducing the opening of the evaporator 8. Accordingly, when the value of ΔTe is larger than the predetermined positive value, the process proceeds to step 58, where the change amount (ΔΘ ′) of the target opening of the mix door 10 is set to “−2”, and the target opening is set. Is gradually reduced so that the absolute value of ΔTe becomes small, that is, the blowout temperature of the evaporator is brought close to the freezing limit temperature.

Conversely, when the value of ΔTe is smaller than a predetermined negative value, the actual blow-out temperature of the evaporator is higher than the freezing limit temperature (2 ° C.). Without changing the opening, the outlet temperature of the evaporator 8 can be lowered by increasing the opening of the mix door 10, so that the routine proceeds to step 60, where the change amount (ΔΘ ′) of the target opening of the mix door 10 is determined. It is set to “+2” so that the target opening is gradually increased so that the absolute value of ΔTe decreases, that is, the blowout temperature of the evaporator approaches the freezing limit temperature.

ΔTe is smaller than a predetermined positive value,
If it is larger than the predetermined negative value, the process proceeds to step 62, and the amount of change in the target opening (ΔΘ ′) is set to “0”.

After the change amount (ΔΘ ') of the target opening is set, in step 64, the previous target opening (Θ') is set.
_OLD ) and the amount of change (ΔΘ ') to obtain a new target opening (Θ').

Then, in the next step 66, based on the difference (Θ-Θ ') between the actual opening (Θ) of the mix door and the new target opening (Θ'), the difference is a positive value equal to or more than a predetermined value. If the value is, the actual opening is larger than the target opening, and the mix door 10 is driven to the cool side (0% side) so that the actual opening approaches the target opening (Θ ') (step 68). If the difference (Θ−Θ ′) is equal to or less than the negative predetermined value, the actual opening is smaller than the target opening, and the actual opening is changed to the target opening (Θ ′).
Mix door on the hot side (100% side)
(Step 70), otherwise, the current position of the mix door 10 is maintained (step 7).
2).

Next, at step 74, the set temperature T
set, the vehicle interior temperature Tr, and the outside air temperature Ta,
The target temperature of the air to be blown into the vehicle compartment (target blow-off temperature T _OF ') is calculated from Equation 1 using a conventionally known method.

[0026]

[Number 1] _{T OF '= a · Tset -b} · Tr -c · Ta + d Note, a, b, c are an arithmetic gain, d represents the correction amount.

After the target outlet temperature T _OF 'has been calculated, at step 76, the rotational speed of the compressor (rpm
m ′) and the outlet temperature immediately after the evaporator (Te) are used as parameters, and an estimated value (T _OF ) of the actual outlet temperature that will be blown into the vehicle interior is calculated based on the characteristic diagram of the same step.

Then, in step 78, a difference (ΔT _OF = T _OF −T _OF ) between the estimated value (T _OF ) of the actual blow temperature and the target blow temperature T _OF ′ calculated in step 74 is calculated. in the next step 80, if the difference ([Delta] T _oF) is positive or greater than a predetermined value, the target outlet air temperature T _oF 'is smaller than the estimated value of the actual air temperature (T _oF), to reduce the T _oF goals In order to approach the blow-out temperature T _OF ', the change amount (Δrpm') of the target rotation speed of the compressor is set to "-50" (step 82), and this change amount (rpm ' _OLD ) is set to the previous target rotation speed (rpm' _OLD ). Δrpm ′) to add a new target rotation speed (r
pm ′), and the rotation of the compressor is controlled based on the rpm ′ (step 88).

Moreover, 'if the following negative predetermined value, the target outlet air temperature T _OF difference _{(ΔT OF = T OF -T OF} )' so is larger than the estimated value of the actual air temperature (T _OF), T _OF In order to make the compressor close to the target blowout temperature T _OF ', the change amount (Δrpm') of the target rotation speed of the compressor is set to "+50" (step 84), and the previous target rotation speed (rpm ' _OLD ) is set.
, The amount of change (Δrpm ′) is added to a new target rotation speed (rpm ′), and the rotation of the compressor 22 is controlled using this rpm ′ (step 88).

If the difference (ΔT _OF ) is other than that, the change amount (Δrpm ′) of the target rotation speed of the compressor is set to “0”.
(Step 86), and the previous target rotation speed (rp
m _'OLD) and controls the rotation of the compressor at the same target rotational speed (step 88).

In the above-described control, for example, considering the rise at the beginning of heating, the target outlet temperature T _OF 'calculated in step 74 is high because the air in the vehicle interior and the outside air are low. Therefore, in the processing of steps 76 to 88, the rotation speed of the compressor is increased so that the deviation of the estimated value (T _OF ) of the actual blow temperature from the target blow temperature T _OF ′ converges to zero.

In this case, in the above-described system, the heat radiation capacity of the sub-capacitor 9 is increased to increase the temperature (Tsc) immediately after the sub-capacitor, but the heat absorption capacity of the evaporator 8 is also increased, and the temperature immediately after the evaporator is increased. (Te) decreases. For this reason, there is a concern that the evaporator may freeze, but if the temperature immediately after the evaporator becomes lower than the limit temperature (2 ° C.) at which the evaporator does not freeze by a predetermined amount or more, the degrees of opening of the mix door 10 are gradually reduced by steps 58 and 64. Become. As shown in FIG. 4, the temperature (Te) immediately after the evaporator has a characteristic of increasing when the opening degree of the mix door 10 becomes small, so that the mix door 10 is brought close to the limit temperature at which the evaporator 8 does not freeze. Is determined.

As is clear from the characteristics shown in FIG. 4, the outlet temperature (Te) immediately after the evaporator and the outlet temperature (Tsc) immediately after the sub-condenser greatly change due to a change in the opening degree of the mix door 10, but the inside temperature of the vehicle interior changes. The temperature of the blown air (T _OF ) does not change significantly even when the opening of the mix door 10 is changed. This is because, when the opening of the mix door 10 is large, the blowout temperature of the sub-condenser 9 decreases, but the amount of air passing through the sub-condenser 9 increases, and when the opening of the mix door 10 is small (for example, around 20%). In (2), although the blowing temperature of the sub-condenser 9 increases, the amount of cool air that bypasses the sub-condenser 9 increases. Therefore, in order to change the blow-out temperature (T _OF ) in the passenger compartment, the temperature is controlled by the rotation speed of the compressor 22 and at the same time the temperature of the evaporator 8 is controlled by the mix door 10 so that the evaporator 8 does not fall significantly below the freezing limit temperature. Therefore, the maximum amount of dehumidification can be ensured and a sufficient heating capacity can be obtained. Note that the above configuration
As an air conditioner installed in electric vehicles
It shows the best mode, and
The drive 22 is driven by the drive motor 34.
However, the compressor whose power is intermittent by the electromagnetic clutch
In automotive air conditioners equipped with
The above-mentioned series is controlled by controlling the duty ratio
Can be controlled.

[0034]

As described above, according to the present invention,
The opening degree of the air mixing door is controlled by the first control means so that the evaporator does not freeze, and the discharge amount of the compressor is controlled by the second control means so as to obtain the required heating capacity. Even if the discharge amount of the compressor increases in the control means and the temperature of the evaporator decreases, the opening degree of the air mix door is adjusted by the first control means to a limit temperature at which the evaporator does not freeze. The heating capacity can be increased while preventing discharge, and the compressor discharges as much as possible even at the beginning of heating in low outside air.
By increasing the output, it is possible to enhance the immediate effect of heating.

[Brief description of the drawings]

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

FIG. 2 is a functional block diagram illustrating an example of an air conditioning control operation by a control unit in FIG. 1;

FIGS. 3A and 3B are flowcharts illustrating an example of an air conditioning control operation performed by a control unit.

FIG. 4 (a) is a diagram showing characteristics of an outlet temperature of an evaporator, an outlet temperature of a sub-condenser, and an outlet temperature into a vehicle compartment with respect to an opening degree of a mix door. FIG.
(B) is a table for explaining characteristics of an evaporator outlet temperature, a sub-condenser outlet temperature, and an outlet temperature into a vehicle compartment with respect to a rotation speed of a compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Air conditioning duct 8 Evaporator 9 Subcondenser 10 Mix door 21 Expansion valve 22 Compressor 24 Main condenser 27 Bypass passage 30 Eva temperature sensor

Claims (1)

(57) [Claims] 1. An environmental factor detecting means for detecting an environmental factor of a vehicle compartment, an evaporator outlet temperature detecting means for detecting an actual outlet temperature of an evaporator, an evaporator in an air-conditioning duct, and a ventilation amount adjusted by a mixing door. Sub-condenser and compressor,
Cooling and heating connecting at least the main condenser, the sub-condenser, the expansion valve, and the evaporator in this order
The cycle and the evaporator outlet temperature detected by the evaporator outlet temperature detecting means are input, and the target opening degree of the air mix door for bringing the outlet temperature of the evaporator closer to the limit temperature at which the evaporator does not freeze is calculated. First control means for driving and controlling the air mix door based on the opening degree, and inputting an output signal of the environmental factor detecting means, and calculating a target outlet temperature to be blown into the vehicle cabin based on the output signal;
Calculating a target discharge quantity of the compressor as the target blowing temperature is obtained, automobile air conditioner, characterized by comprising a second control means for driving and controlling the compressor based on the target discharge amount Equipment control device .