JP2995437B2 - Compressor capacity control device for vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle having a variable displacement compressor, and more particularly to a compressor displacement control device for suppressing variations in engine speed during idling caused by a change in the displacement of the compressor. .

[0002]

2. Description of the Related Art Conventionally, an air conditioner for a vehicle employs a system driven by a driving engine. Therefore, a load applied to the driving engine fluctuates due to a change in the load of the air conditioner. At times, the rotation speed of the traveling engine fluctuated.

In order to suppress the variation of the engine speed during idling, an idle speed control device disclosed in Japanese Patent Application Laid-Open No. 61-135953 discloses a cooling load applied to an air conditioner driven by a driving engine. A first sensor that detects a physical quantity related to a cooling load calculation device that receives a signal from the first sensor and calculates a cooling load;
The cooling load is calculated by a cooling load calculating means from a signal of a physical quantity related to the cooling load detected by the first sensor. The cooling load is calculated by a control device configured to control an idle speed according to the cooling load. Is larger, the idle speed is set higher than usual.

[0004]

However, in the above-mentioned reference, in a state where the operation of the air conditioner is stable, the value detected by the first sensor is determined by, for example, a change in heat load or a change in evaporator temperature distribution. Accordingly, the load of the variable displacement compressor fluctuates correspondingly, and in order to keep the idling speed of the engine constant, a program executed by the engine control device becomes complicated. There has been a problem that it is necessary to perform fine engine control, and the structure of the engine control system is complicated to cope with this. Further, in a vehicle such as a diesel vehicle that performs only a constant idle-up, there is a problem that a change in the engine load due to a change in the capacity of the variable displacement compressor appears as a change in the idle speed as it is.

Accordingly, the present invention provides a compressor displacement control device for a vehicle air conditioner that suppresses fluctuations in the engine speed during low-speed operation of the engine by suppressing fluctuations in the load of the compressor, which is an engine load. To provide.

[0006]

The present invention will be described with reference to FIG. 1. In the air conditioning duct, there is provided a temperature control means comprising a cooling means and a heating means, and the cooling means comprises at least a compressor, a condenser, A cooling cycle comprising an expansion valve and an evaporator, the evaporator temperature is detected in a vehicle air conditioner which is a variable capacity compressor 10 capable of changing the amount of refrigerant discharged from the compressor by an external control signal. Evaporator temperature detecting means 100, vehicle speed detecting means 110 for detecting a vehicle speed of the vehicle, and calculating a target evaporator temperature from at least the evaporator temperature detected by the evaporator temperature detecting means 100, an environmental signal indicating an environmental state, and a vehicle interior set temperature. Target evaporator temperature calculating means 120 When the vehicle speed detected by the vehicle speed detecting means 110 is equal to or more than a predetermined value or the vehicle speed is equal to or less than a predetermined value and the evaporator temperature detected by the evaporator temperature detecting means 100 does not reach the target evaporator temperature, The control signal is calculated by a first gain from the difference between the evaporator temperature and the detected evaporator temperature, and when the vehicle speed is equal to or less than a predetermined value and the evaporator temperature reaches the target evaporator temperature, the target evaporator temperature is set. And a compressor capacity control signal calculating means 130 for calculating the control signal with a second gain smaller than the first gain from a difference between the detected evaporator temperature and the detected evaporator temperature. Compressor capacity by control signal Some to and a compressor capacity control means 140 for variably.

[0007]

Therefore, according to the present invention, if the evaporator temperature detected by the evaporator detection means 100 does not reach the target evaporator temperature calculated by the target evaporator temperature calculation means 120, the first
When the evaporator temperature has reached the target evaporator temperature and the vehicle speed detected by the vehicle speed detecting means 110 is equal to or lower than a predetermined value, the compressor capacity control signal is calculated by the gain of the first gain. By calculating the compressor displacement control signal with the second gain, when the evaporator temperature reaches the target evaporator temperature and the engine speed is low, the change in compressor displacement is suppressed, so that the load on the engine is suppressed. The above object can be achieved.

[0008]

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

The vehicle air conditioner shown in FIG.
An air intake unit 2 is provided upstream of the air conditioning duct 1. The air suction unit 2 has an inside air inlet 3, an outside air inlet 4, and an inside / outside air switching door (intake door) 5 for appropriately opening and closing the inside air inlet 3 and the outside air inlet 4. Numeral 5 is driven by an actuator 6.

A blower 7 is provided downstream of the air suction unit 2, and an evaporator 8 and a heater core 9 as temperature control means are provided downstream of the blower 7. The evaporator 8 includes a variable displacement compressor 10 having a displacement variable mechanism 24 described below, which is connected to a traveling engine 14 via an electromagnetic clutch 15, and a condenser 1.
1 and a pipe connected in series with the receiver tank 12 to form a cooling cycle. The heater core 9 uses cooling water supplied from the traveling engine 14 as a heat source, and the heater core 9 is provided upstream of the heater core 9.
Air mixing door 1 for adjusting the amount of air passing through
The air mix door 16 is driven by an actuator 17.

At the most downstream of the air conditioning duct 1, there is a differential air outlet 1
8, a vent outlet 19 and a foot outlet 20 open toward the interior of the passenger compartment 21, and the mode doors 22a, 22b,
The mode doors 22 a, 22 b, and 22 c are appropriately selected and opened by the actuator 23.
It is driven by.

In the vehicle air conditioner having the above structure, the inside air or the outside air sucked by the drive of the blower 7 from the inside air inlet 3 or the outside air inlet 4 selected by the intake door 5 passes through the evaporator 8. Cooled. The cooled air is supplied to the air mix door 1
At 6, air is divided into air passing through the heater core 9 and air bypassing the heater core 9. The air heated through the heater core 9 and the cooled air bypassing the heater core 9 are mixed on the downstream side of the heater core 9 to become air adjusted to a desired temperature. The temperature-controlled air is supplied to the mode doors 22a, 22a.
outlets 18, 19, 20 selected by b, 22c
Then, the air is blown into the passenger compartment 21 to control the temperature of the passenger compartment 21.

The variable displacement compressor 10 is, for example, of a wobble plate type. FIG. 3 shows an example of the wobble plate type, and its configuration will be outlined.

A drive shaft 51 connected to the traveling engine 14 via an electromagnetic clutch 15 is provided with a compressor body 10a.
And a wobble plate 52 is connected to the drive shaft 51 via a hinge ball 53. The wobble plate 52 is supported by a crank chamber 54 formed in the compressor main body 16a so as to be swingable with respect to the drive shaft 51 with a hinge ball 53 as a fulcrum. Is reciprocated in the cylinder bore 56 in accordance with each swing.

The compressor 10 has a pressure control valve 5
7 is provided so as to face the crank chamber 54. this
The pressure regulating valve 57 is provided with a suction passage communicating with the crank chamber 54 and the suction side.
A valve body 59 for adjusting a communication state with the entrance chamber 58;
Pressure responsive member that moves the valve body 59 in accordance with the pressure in the pressure 8
60 and the valve body 59 is electrically connected to the electromagnetic coil 61 by an amount I
_SOLSolenoid 6 that moves according to (capacity variable control signal)
2 and the amount of current I to the electromagnetic coil 61_SOLThe outside
Control the piston 55 and the syringe
Blow leaking into the crank chamber 54 from between the dowel 56
The amount of the bigas returning to the suction side is adjusted.

Thus, the pressure adjusting valve 57 and the like constitute the variable capacity mechanism 24 for changing the capacity of the compressor 10. When the amount of current I _SOL flowing through the electromagnetic coil 61 increases and the magnetic force of the solenoid 62 increases, the valve body The force acts in the direction in which the cylinder 59 reduces the communication between the crank chamber 57 and the suction chamber 58, and the amount of blow-by gas leaking from the crank chamber 57 to the suction chamber 58 decreases. For this reason, the pressure in the crank chamber 57 increases and the stroke of the piston 55, that is, the compressor discharge capacity decreases.

In order to control the air conditioner, at least a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), not shown,
A known microcomputer 41 constituted by an input / output port (I / O) and the like is provided. The microcomputer 41 includes a vehicle interior temperature sensor 43 provided in the vehicle interior 21, an outside air temperature sensor 44,
Signals from an evaporator temperature detection sensor 45, a solar radiation sensor 46, and a vehicle speed sensor 47 for detecting the speed of the vehicle are input to a multiplexer (MPX) 47, and sequentially A / D converters 48 in accordance with instructions from the microcomputer 41.
Is input to the microcomputer 41 via the. The microcomputer 41 receives signals from the operation panel 25 described below.

The operation panel 25 includes an AUTO switch 31 for automatically performing air conditioning control, an OFF switch 32 for stopping the operation of the air conditioner, and a REC for manually switching the intake air mode to the inside air circulation mode or the outside air introduction mode.
A switch 33, a DEF switch 34 for manually setting the blowing mode to the differential mode, an A / C switch 35 for manually turning on / off the operation of the cooling cycle, an AMB switch 36 for presenting the outside air temperature to the display unit 30, A vehicle interior temperature setting device 28 comprising an up switch 28a and a down switch 28b for setting, a FAN switch 27 for manually setting the air volume of the blower 6, and a manual blow mode for an upper blow mode (vent mode) or a lower blow mode (heat). (Mode), and a display unit 30 for displaying the current air-conditioning state controlled by the microcomputer 41 via the display circuit 29.

Signals input to the microcomputer 41 from the sensors 43 to 47 and the operation panel 25 are converted into control signals processed by a predetermined program in the microcomputer 41, and each output circuit 40a
The actuators 6, 17, 23, the blower 7, the variable displacement mechanism 24, and the electromagnetic clutch 15 are controlled via the output circuits 40a to 40e.

FIG. 4 is a flowchart of the main routine of the air conditioning control executed by the microcomputer 41. The air conditioning is started from step 200 when an ignition switch (not shown) is turned on when the ignition switch (not shown) is turned on. The main routine of the control is as follows.
Is input as switch (SW) data, and in step 220, the temperature sensor 4
Signals from 3, 44, 45, 46 and the speed detection sensor 47 are read as sensor data inputs.

In step 220, a total signal T as a heat load signal is calculated from the data, the vehicle interior temperature Td, the outside air temperature Ta, the solar radiation amount T _SUN , the evaporator temperature Te, and the vehicle interior set temperature T _SET by the following equation 1. Is done.

[0022]

T = K ₁ Td + K ₂ Ta + K ₃ T _SUN + K ₄ Te−K ₅ T _SET + K ₆

K ₁ , K ₂ , K ₃ , K ₄ , and K ₅ are gain constants obtained by experiments so as to increase the optimum air-conditioning effect that matches the vehicle, and K ₆ is obtained in the same manner. Correction term.

The control of the intake door 5 executed in the step 240 is based on the total signal T when the AUTO switch 31 is turned on, in accordance with the characteristic line shown in FIG. The mode is automatically switched to the introduction (FRE) mode, and when the REC switch 33 is operated, the mode is manually switched to the REC mode or the FRE mode according to the instruction.

When the AUTO switch 31 is turned on, the control of the blower 7 executed in step 250 is performed based on the total signal T in accordance with the characteristic line shown in FIG. Rotation (LOW),
High rotation (HI), and linearly change between them,
In addition, low rotation (L
OW), medium rotation (MID), high rotation (HI), or maximum rotation (MAX HI).

The control of the air mix door 16 executed in step 260 is based on the total signal T shown in FIG.
According to the characteristic line shown in (c), the temperature changes linearly from a full cool (F / C) position where the heater core 9 is fully closed to a full hot (F / H) position where the heater core 9 is fully opened.

The control of the mode doors 22a, 22b and 22c executed in step 270 is as follows. When the AUTO switch 33 is turned on, the vent outlet 19 is opened based on the total signal T according to FIG. A vent (VENT) mode, a bi-level (BI / L) mode in which the opening ratio of the vent outlet 19 and the foot outlet 20 is linearly changed by the total signal T, or a heat (HEAT) mode in which only the foot outlet 20 is opened The mode is switched manually by the MODE switch 26 to an upper blowing mode in which only the vent outlet 19 is opened or a lower blowing mode in which only the foot outlet 20 is opened.

In step 280, the following compressor control is executed, and in step 290, DE control is performed.
Other controls such as control by turning on the F switch 34 and control of the display unit 30 of the operation panel 25 are executed, and the process returns to step 210.

The compressor control (C) shown in FIGS.
The subroutine I (SUB I) of the OMP control) is started from step 300. In step 310, the operation status of the OFF switch 32 of the operation panel 25 is determined. If the OFF switch 32 is not pressed, the process proceeds to step 320. The process proceeds to determine whether or not the A / C switch 35 is ON.
Is pressed and if the A / C switch 35 is OFF in step 320, the process proceeds to step 330, where "A / C OFF" is manually set, and
In step 340, the control of the OFF mode of the compressor 10 is executed.

If the A / C switch 35 is ON in step 320, the outside air temperature Ta is determined in step 350. In this judgment, a hysteresis is provided.
If A is selected, it is determined that cooling is not necessary if A is selected, and the process proceeds to step 340 via the connector C and the compressor 10 is turned off.
The F mode is set. If B is selected in step 350, A is set in step 360.
It is determined whether the / C switch 35 is ON.

If the A / C switch 35 is ON in step 360, the process proceeds to step 430. If the A / C switch 35 is not ON, the process proceeds to step 370 to turn on the DEF switch 34. Is determined. In this judgment, DEF
If the switch 34 is turned on, step 43
It goes to zero. In this step 430, "A / C MAX" is set manually, and the process proceeds to step 440 via the connector E.

In 380, the temperature setting unit 28
If the vehicle interior set temperature T _SET has been set to the minimum temperature (MAX COOL), the process proceeds to step 440,
Otherwise, the process proceeds to step 390, and if the vehicle interior set temperature T _SET has been set to the maximum temperature by the temperature setting device 28 (MAX HEAT), the process proceeds to step 340 via the connector C and proceeds to step 340. 10 is to stop.

If it is determined in steps 380 and 390 that the vehicle interior set temperature T _SET is not set to the minimum temperature or the maximum temperature, the process proceeds to step 400 to determine whether or not the outside air temperature Ta is equal to or higher than a predetermined value. A determination is made. In this determination, a hysteresis is provided. When the hysteresis is equal to or more than a predetermined value, it is determined that the outside air temperature is high (B), and the normal
The N mode is set. Step 40
If the outside air temperature Ta is equal to or less than the predetermined value and A is selected in the determination of 0, the intake door 5
If the control state is determined to be the inside air circulation (REC) mode, step 420 is bypassed and step 4 is skipped.
Proceeding to 60, in the case of the outside air introduction (FRE) mode, proceeding to step 420, the opening of the air mix door 16 is determined.

[0034] A hysteresis is provided in this determination, if the opening theta _X of the air mixing door 16 is less than the predetermined value in step 460, if it is more than the predetermined value in which the flow proceeds to step 340.

In step 460, the compressor 10
After the normal ON mode is set, in step 470, the calculation of the target evaporator temperature T'e is obtained according to the characteristic line shown in FIG. Thereafter, in step 480, the following SU
B II Compressor capacity control is executed, and step 49
The process returns from 0 to the main routine.

As described above, in the SUB I compressor control (COMP control), the operation panel 2
5, when the A / C switch 35 is turned off, when the outside air temperature is equal to or lower than a predetermined value, the temperature setting unit 28 sets the vehicle interior set temperature T _SET to the maximum temperature. Or the opening Δx of the air mixing door 16 is equal to or more than a predetermined value, the compressor 10 is stopped.
OFF mode is set, and the A / C switch 35 is
N, when the DEF switch 34 is ON,
Alternatively, when the vehicle interior set temperature T _SET is MAX COOL set to the lowest temperature, the mode is set to the A / C MAX mode. In other cases, the normal ON mode is set.

The capacity control subroutine (SUB II) of the compressor 10 shown in FIG. 9 is started from step 500, and the vehicle speed is determined in step 510. In this determination, the vehicle shifts from B to A at 10 [km / h] when the vehicle speed is decreasing, and shifts from A to B at 20 [km / h] when the vehicle speed is increasing. Hysteresis is provided, and A is prioritized between 10 [km / h] and 20 [km / h]. In this determination, when the vehicle speed is equal to or less than the predetermined value (A), it is determined that the engine speed is low, and step 520 is performed.
If the value is equal to or more than the predetermined value (B), the process proceeds to step 540.

In step 520, the program 1 (P
It is determined whether or not FLAG1 indicating that ROG I) has been executed is 1, and if FLAG1 is 1, the process proceeds to step 560. If FLAG1 is not 1, the process proceeds to step 530 to determine the evaporator temperature. The magnitudes of Te and the target evaporator temperature T'e are determined. In this determination, the evaporator temperature Te becomes equal to the target evaporator temperature T ′.
If it is lower than e, the process proceeds to step 560, and if the evaporator temperature Te is equal to or higher than the target evaporator temperature T'e, the process proceeds to step 580.

The program 2 (PROGII) specified in step 540 and step 580 corresponds to FIG.
The proportional term (PI) of I _SOL is calculated from the difference between the evaporator temperature Te and the target evaporator temperature T′e by the ordinary characteristic line shown by the solid line PROG II shown in FIG. PROG II indicated by
The integral term of I _SOL (I
I) is calculated, whereby I _SOL is calculated by the following equation (2).

[0040]

## EQU2 ## I _SOL = PI + II

The program 1 (PROG I) specified in step 560 is the program 1 (PROG I) shown in FIGS.
The proportional term (PI) and the integral term (II) are obtained by the characteristic line indicated by the one-dot chain line of the ROG I. Since the gain of the PROG I is smaller than that of the PROG II, the calculation is performed. This is to reduce the fluctuation of the I _SOL value. The characteristic diagram shown in FIG.
It is used in a portion surrounded by a chain line 700 in FIG.

[0042] After this, in the case where if I _SOL is determined by PROG II by steps 540 and 580 the FLAG1 in step 550,590 and "0" to determine the I _SOL by PROG I in step 560 FLAG1 Is set to “1” and the process returns from step 600 to the subroutine (SUB I).

As a result, as shown in FIG. 11, the normal gain (PROG I
The compressor capacity control is performed according to I), and the evaporator temperature Te decreases rapidly. Thereafter, after the evaporator temperature Te becomes equal to the target evaporator temperature T′e, the compressor capacity control is performed with a small gain (PROG).
11), the detection value Te of the evaporator temperature detection sensor 45 fluctuates due to the influence of another control device (FIG. 11A).
_Since the change to the _SOL value can be suppressed, the variation of the engine speed shown in FIG. 11C can be suppressed. It should be noted that the broken lines shown in FIGS.
In the case where the control by the gain of PROG II is continued, it indicates that the engine load fluctuates due to the fluctuation of the _ISOL value due to the fluctuation of the detected evaporator temperature Te, thereby causing the fluctuation of the engine speed. Things.

[0044]

As described above, according to the present invention, when the difference between the evaporator temperature and the target evaporator temperature is large at the initial stage of starting the air conditioner, the compressor capacity control signal for determining the compressor capacity is calculated. After the evaporator temperature reaches the target evaporator temperature, the gain of each item for calculating the compressor displacement control signal is reduced compared to the gain to increase the evaporator temperature. In order to suppress the influence of the fluctuation on the compressor displacement control signal, it is possible to suppress the variation in the engine speed when the engine is running at a low speed.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

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

FIG. 3 is a sectional view of a variable displacement compressor according to the embodiment of the present invention.

FIG. 4 is a flowchart of a main routine of the air conditioner executed by the microcomputer.

5A is a characteristic diagram showing a relationship between a total signal and inside air introduction mode switching, FIG. 5B is a characteristic diagram showing a relationship between a general signal and rotation of a blower, and FIG. FIG. 4 is a characteristic diagram showing a relationship between the total signal and the air mix door opening, and FIG. 4D is a characteristic diagram showing a relationship between the total signal and the blowout mode.

FIG. 6 is a first half of a flowchart of a subroutine of a compressor control executed by the microcomputer.

FIG. 7 is a second half of a flowchart of a subroutine of compressor control executed by the microcomputer.

FIG. 8 is a characteristic diagram showing a relationship between a total signal and a target evaporator temperature.

FIG. 9 is a flowchart of a subroutine of compressor capacity control executed by the microcomputer.

10A is a characteristic diagram showing a relationship between a difference between an evaporator temperature Te and a target evaporator temperature T′e and a proportional term, and FIG. 10B is a graph showing a relationship between the evaporator temperature Te and the target evaporator temperature T′e. FIG. 4 is a characteristic diagram showing a relationship between a difference and an integral term.

11 (a) is a timing chart showing a change in evaporator temperature Te, FIG. 11 (b) is a timing chart of an _ISOL value, and FIG. 11 (c) is a timing chart of an engine speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Variable displacement compressor 100 Evaporator temperature detecting means 110 Vehicle speed detecting means 120 Target evaporator temperature means 130 Compressor capacity control signal calculating means 140 Compressor capacity controlling means

Claims (1)

(57) [Claims] 1. An air conditioning duct having a temperature control means comprising cooling means and heating means, wherein said cooling means is a cooling cycle comprising at least a compressor, a condenser, an expansion valve and an evaporator. In a vehicle air conditioner, which is a variable capacity compressor that can vary the amount of refrigerant discharged by an external control signal, evaporator temperature detecting means for detecting an evaporator temperature, vehicle speed detecting means for detecting a vehicle speed of the vehicle, A target evaporator temperature calculating means for calculating a target evaporator temperature from at least the evaporator temperature detected by the evaporator temperature detecting means, an environmental signal indicating an environmental state, and a vehicle interior set temperature; and a vehicle speed detected by the vehicle speed detecting means being a predetermined value. Or the vehicle speed is below a predetermined value and When the evaporator temperature detected by the evaporator temperature detecting means has not reached the target evaporator temperature, the control signal is calculated by a first gain from a difference between the target evaporator temperature and the detected evaporator temperature. When the vehicle speed is equal to or less than a predetermined value and the evaporator temperature reaches the target evaporator temperature, the second gain smaller than the first gain is obtained from the difference between the target evaporator temperature and the detected evaporator temperature. A compressor capacity control signal calculating means for calculating a control signal; and a compressor capacity control means for varying a compressor capacity by a control signal calculated by the compressor capacity control signal calculating means. Compressor capacity control device.