JP2001270323A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a control of an air conditioning control instrument corresponding to a characteristic variation of an expansion valve. SOLUTION: An air conditioner for vehicle is provided with an environment load detection means for detecting an environment load of a refrigeration cycle; an urging force control means for controlling an urging force adjusting means for adjusting an urging force of an urging means for urging a valve element of an expansion valve corresponding to the environment load detected by the environment load detection means; and an air conditioner control means for controlling the air conditioner control instrument corresponding to the urging force of the urging means controlled by the urging force control means. The respective air conditioner control instruments are controlled so as to be coincident with an expansion valve characteristic determined by the environment load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, particularly to an air conditioner mounted on a vehicle, which has a refrigeration cycle provided with an expansion valve capable of changing a characteristic of a degree of superheat.

[0002]

2. Description of the Related Art For example, a block type expansion valve as disclosed in Japanese Patent Application Laid-Open No. 8-136,881 is provided for detecting the outward path to an evaporator having a valve mechanism and the temperature and pressure of refrigerant flowing out of the evaporator. It has a return path, and the temperature of the refrigerant passing through the return path is transmitted to gas in a closed space provided at the end of the rod via the rod of the valve mechanism, and the pressure of the refrigerant is reduced by the rod Is transmitted to the closed space via a diaphragm defining a closed space provided at the end of the closed space. Accordingly, when the temperature (degree of superheat) of the refrigerant flowing out of the evaporator is high, the gas in the closed space expands and moves in a direction to open the valve via the rod, and the amount of refrigerant flowing through the outward path , The degree of superheat decreases. When the pressure of the refrigerant is high, the volume in the closed space decreases, and the rod is pulled up, so that the valve moves in the closing direction, the amount of the refrigerant decreases, and the pressure drops. As described above, the diaphragm moves to move the valve body so as to keep the temperature (degree of superheat) or pressure of the refrigerant flowing out of the evaporator constant, so that a constant degree of superheat and discharge pressure can be obtained.

[0003]

However, in the block type expansion valve having the above-described structure, the degree of superheat varies depending on the strength of the coil spring that urges the valve body toward the valve seat, so that it is very difficult to adjust the coil spring. In the case where the opening degree of the expansion valve is adjusted by electronic control, there is a problem that the number of parts is large and the control becomes complicated as compared with the mechanical type. For this reason, the present applicant has, in Japanese Patent Application No. 11-72813, provided a means for detecting an environmental load of a refrigeration cycle, and an adjusting means for adjusting the urging force of the coil spring according to the detected load. An expansion valve that changes the superheating degree characteristic of a refrigeration cycle by changing the biasing force of a coil spring has been disclosed.

Further, in a vehicle air conditioner using a refrigeration cycle equipped with this expansion valve, even if the control characteristics of the expansion valve change, the air conditioning control device, especially the blower and the compressor, is controlled in accordance with the change. Therefore, even if the expansion valve is controlled well, there is a problem that a good air-conditioning state cannot be obtained.

Further, when the environmental load is low, the discharge amount of the compressor is usually low, so that the amount of circulating refrigerant is reduced. And the amount of lubricating oil for lubricating the compressor is reduced, which causes a burn-in of the compressor and the like, which leads to a failure of the air conditioner itself.

[0006] Therefore, an object of the present invention is to provide a vehicle air conditioner capable of controlling a blower and a compressor in response to a change in characteristics of an expansion valve and maintaining a good air conditioning state.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention constitutes a refrigeration cycle together with an evaporator disposed in an air-conditioning duct, and adjusts a position of a valve body by adjusting a temperature and a pressure of a refrigerant at an outlet of the evaporator. An air-conditioning duct as an air-conditioning control device, comprising an expansion valve having an adjusting means, an urging means for urging the valve body in a closing direction, and an urging force adjusting means for adjusting the urging force of the urging means. In a vehicle air conditioner having a blower disposed therein and a compressor constituting a part of a refrigeration cycle, an environmental load detecting means for detecting an environmental load of the refrigeration cycle, and an environmental load detected by the environmental load detecting means. Urging force control means for controlling the urging force adjusting means in accordance with the air conditioner, and the air conditioning in accordance with the urging force of the urging means controlled by the urging force control means. It is to and a air conditioning control means for controlling the control device.

Therefore, according to the present invention, since each air-conditioning control device is controlled so as to match the expansion valve characteristic determined by the environmental load, it is possible to maintain a good air-conditioning state and to solve the problem of the refrigeration cycle. Therefore, the above problem can be achieved.

The urging force control means may be configured to switch the urging force between a low superheat degree control state in which the urging force of the urging means is reduced and a high superheat degree control state in which the urging force of the urging means is increased. It may control the adjusting means. Accordingly, when the urging force of the urging means is reduced, the urging force for urging the valve body decreases, so that the amount of refrigerant flowing through the refrigeration cycle increases, the degree of superheat decreases, and the urging force of the urging means increases. Then, the urging force for urging the valve body increases, so that the amount of refrigerant flowing through the refrigeration cycle decreases and the degree of superheat increases.

Further, the biasing force control means includes a high load determining means for determining whether the environmental load detected by the environmental load detecting means is greater than a first predetermined value, and In the case of a high load greater than a predetermined value of 1, the urging force adjusting means is controlled to bring the urging means into a low superheat degree control state, and when the environmental load is a low load smaller than the first predetermined value, Controls the urging force adjusting means to drive the urging means to a high superheat degree control state.

[0011] Thus, the urging force control means may control the environmental load detected by the environmental load detecting means to the first level.
In the case of a so-called high load, which is larger than the predetermined value, the urging force adjusting means is controlled to bring the urging means into a low superheat degree state where the urging force is small (hereinafter, referred to as a B characteristic of the expansion valve). When the environmental load detected by the environmental load detecting means is smaller than a first predetermined value, the urging means is set to a high superheat state where the urging force of the urging means is large (hereinafter referred to as the A characteristic of the expansion valve). To set. Accordingly, when the environmental load is large, the urging force of the urging means of the valve body is reduced (the B characteristic is selected), so that the degree of superheat of the refrigeration cycle is reduced, and the amount of refrigerant supplied to the evaporator is increased. To increase the cooling power of the refrigeration cycle,
Further, when the environmental load is small, the urging force of the urging means of the valve body is increased (A characteristic is selected), so that the degree of superheat of the refrigeration cycle increases, and the amount of refrigerant supplied to the evaporator decreases. In addition, since the cooling power of the refrigeration cycle is limited, an optimum cooling power can be provided.

Further, according to the present invention, the air conditioning control means includes a blower control means, and the blower control means, when the cooling means is started, when the urging means is in a low superheat degree control state. As compared with the case where the power supply means is in the high superheat degree state, the stop time of the blower at the start of startup is made longer, and
An object of the present invention is to reduce the rate of increase in the rotation speed of a blower.

Further, at the time of cooling start, when the urging means is in the low superheat control state (when the B characteristic is selected), when the urging means is in the high superheat control state (the A characteristic is low). (When selected), the stop time of the blower at the beginning of startup is lengthened, and the rate of increase in the rotation speed of the blower is reduced. Thereby, when the environmental load is large at the time of startup, the temperature of the evaporator can be reduced because the air blower is stopped for a long time in the early stage of the air blower startup. Temperature rise can be suppressed, and the blown air temperature can be quickly reduced.

Further, in the present invention, at the time of cooling down, the blower control means reduces the air volume of the blower when the urging means is in a low superheat state (when the B characteristic is selected). It is to let. As a result, the temperature of the evaporator can be reduced, so that the cool-down can be performed well.

Still further, in the present invention, the blower control means reduces the air flow during idling stop and reduces the air flow when the urging means is in a low superheat state (when the B characteristic is selected). , When the urging means is in a state of high superheat (when the A characteristic is selected)
Is set smaller than the air volume. With this, when the compressor is stopped during idle stop, the air volume is reduced, so that an increase in the blow-out temperature can be suppressed. At times, when the environmental load is large and the B characteristic is selected, the airflow is further reduced as compared with the case where the environmental load is small and the A characteristic is selected, so that the temperature rise of the evaporator can be suppressed, and the idle stop can be performed. It is possible to hasten the return of the air-conditioning state when it is released.

Further, in the present invention, the biasing force control means has a low load determination means for determining whether or not the environmental load detected by the environmental load detection means is smaller than a second predetermined value. When the environmental load is a low load smaller than the second predetermined value, the control unit controls the urging force adjusting unit to bring the urging unit into a low superheat degree control state.
That is, the urging force control unit further includes a low load determination unit that determines whether the environmental load detected by the environmental load detection unit is smaller than a second predetermined value smaller than the first predetermined value. When the environmental load is a high load larger than the first predetermined value and a low load smaller than the second predetermined value, the control unit controls the urging force adjusting unit to lower the urging unit. In the superheat control state, the environmental load is smaller than the first predetermined value and the second
In the case of a medium load larger than the predetermined value, the urging force adjusting means is controlled to bring the urging means into a high superheat degree control state.

Further, in the present invention, the air conditioning control means includes a compressor control means, and the compressor control means is provided when the environmental load is lower than the second predetermined value and the urging means is low. When the degree of superheat is controlled (when the B characteristic is selected), the discharge amount of the compressor is increased. Thus, when the environmental load is low, by selecting the B characteristic and setting a large discharge amount of the compressor, the circulation amount of the refrigerant can be further increased. Can be regressed.

Further, in the present invention, the compressor control means increases the discharge amount of the compressor when the urging means is in a low superheat degree control state during idle stop (when the B characteristic is selected). Is to do. Thus, even when the engine is stopped, the circulation amount of the refrigerant can be increased, so that the temperature of the evaporator can be reduced.

[0019]

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

As shown in FIG. 1, the vehicle air conditioner 1 comprises:
An air-conditioning duct 2 is provided in the passenger compartment. An outside air inlet 3 and an inside air inlet 4 which are opened and closed by an intake door 5 are opened at the most upstream side of the air-conditioning duct 2, and a mode is provided at the most downstream side. A defrost outlet 10, a vent outlet 11, and a foot outlet 12 which are opened and closed by doors 13, 14, 15 are opened.

A blower 6 is provided in the air-conditioning duct 2 to suck air from the inlets 3 and 4 selected by the intake door 5 and send the air downstream. An evaporator 7 for cooling the passing air is provided downstream of the blower 6. The evaporator 7 constitutes a refrigeration cycle 20 together with the compressor 21, the condenser 22, the gas-liquid separator 23 and the expansion valve 30.

On the downstream side of the evaporator 7, a heater core 8 for heating the air passing therethrough is provided. On the upstream side of the heater core 8, the air passing through the evaporator 7 is combined with the air passing through the heater core 8. Heater core 8
An air mix door 9 is provided for diverting air to the air that bypasses the heater core 8, and the degree of air mixed downstream of the heater core 8 is adjusted by the degree of opening of the air mix door 9,
The temperature is adjusted.

Further, the vehicle air conditioner 1 having the above-described configuration.
Are various air-conditioning control devices, for example, an actuator 53 for driving the intake door 5, a motor for the blower 6, an actuator 54 for driving the air mix door 9, an actuator 55 for driving the mode doors 13, 14, 15; And a control unit 50 for controlling the variable displacement mechanism 52 and the like when the compressor 21 is a variable displacement compressor. The control unit 50 includes a central processing unit (CP) (not shown).
U), read-only memory (ROM), random access memory (RAM), input / output port (I / O), and
It is a well-known device including a drive circuit and the like connected to the output port.
3, the temperature detection signal from the evaporator wake side temperature sensor 64, the solar radiation detection signal from the solar radiation sensor 65, and
A setting signal is input from the operation panel 56, processed by a predetermined program, and then output as an output signal to the above-described air conditioning control device. The operation panel 56
Are the manual air volume setting device 57 and the suction mode setting device 5
8, at least a blow mode setting device 59, a temperature setting device 60 for turning on / off air conditioning, switching between cooling and heating, and setting a target temperature, and a display portion 61 for displaying an air conditioning status.

The expansion valve 30 is, for example, a block type expansion valve as shown in FIG. 2, and is a valve opening adjusting mechanism for adjusting the valve opening by driving a block body 30A and a valve body 39 of a valve mechanism 38. 30B and an urging force adjusting mechanism 30C that adjusts the force of a coil spring as urging means for urging the valve body 39 toward the valve seat 40 side.

The block main body 30A is connected to a refrigerant inlet 31 to which a pipe from the gas-liquid separator 23 is connected and a refrigerant outlet 32 to which a pipe to the inflow side of the evaporator 7 is connected. Refrigerant passage 33 and a refrigerant inlet 34 to which a pipe from the outlet side of the evaporator 7 is connected.
And a second refrigerant passage 37 which communicates with a refrigerant outlet 35 to which a pipe to the suction side of the compressor 21 is connected. The first refrigerant passage 33 is opened and closed by the valve body 39. The valve seat 40 is formed.

The valve mechanism 38 includes a valve body 39, the valve seat 40, a rod 45, one end of which contacts the valve body 39 and moves the valve body 39 relative to the valve seat 40.
A coil spring 41 for urging the valve body 39 toward the valve seat 40
And a valve pressing member 4 provided at one end of the coil spring 41 and transmitting the urging force of the coil spring 41 to the valve body 39.
2 and an adjustment nut 43 for holding the other end of the coil spring 41. Reference numeral 42a is a support rod that movably supports the valve holding member 42.

The valve opening adjusting mechanism 30B includes a rod 45 extending through the second refrigerant passage 37.
And a sealed space 47 defined by the diaphragm 46 and filled with a gas at a predetermined density inside the diaphragm 46. The sealed space 47 is further interposed through the diaphragm 46. 47
On the opposite side, a pressure space 48 communicating with the second refrigerant passage 37 is formed. The gas is desirably the same gas as the refrigerant, and the sealing pressure is desirably a saturated vapor pressure.

Thus, the temperature of the refrigerant passing through the second refrigerant passage 37, that is, the temperature of the refrigerant flowing out of the evaporator 7, is transmitted to the gas in the closed space 47 defined by the diaphragm 46 via the rod 45. Is done. When the temperature of the refrigerant is high (the degree of superheat is high), the gas in the closed space 47 expands and the diaphragm 46 expands, so that the rod 45 is pushed and the valve body 39 is moved to the valve seat. As a result, the amount of the refrigerant sent to the evaporator 7 increases, so that the temperature of the refrigerant passing through the second refrigerant passage 37 decreases. Conversely, when the refrigerant temperature is low, the valve element 39 approaches the valve seat 40, and the amount of refrigerant sent to the evaporator 7 decreases, so that the refrigerant temperature rises.

When the pressure (low pressure) of the refrigerant passing through the second refrigerant passage 37 is high and the pressure space 48 is larger than the pressure of the closed space 47, the direction in which the diaphragm 46 contracts. , The valve body 39 moves in the closing direction, and the amount of refrigerant sent to the evaporator 7 decreases, so that the low pressure can be reduced.
Conversely, when the low pressure is low and the pressure space 48 is smaller than the pressure in the closed space 47, the diaphragm 4
6 expands, the valve element 39 moves in the opening direction, and the amount of refrigerant sent to the evaporator 7 increases, so that the low pressure can be increased. From the above, the expansion valve 30 is driven so as to keep the temperature and pressure of the low-pressure refrigerant constant.

The expansion valve 30 has an urging force adjusting mechanism 30C. The urging force adjusting mechanism 30C adjusts the urging force of the coil spring 41 by moving the adjusting nut 43 with respect to the coil spring 41.
4a, a motor 44 having an engagement nut 43, an engagement hole 43a formed in the adjustment nut 43 and engaged with the drive shaft 44a, and a screw portion 43b formed around the adjustment nut 43. The motor 44 is a stepping motor in this embodiment, and is driven by a control signal from the control unit 50.

The urging force adjusting mechanism 30C is driven, for example, based on an expansion valve characteristic control program for selecting an expansion valve characteristic executed according to a flowchart shown in FIG. The expansion valve characteristic control started from step 100 is, for example, an attached routine periodically started from the main control routine of the air conditioning control. The outside air temperature Tam detected by the outside air temperature sensor 62 in step 110 is input. . Then, the outside air temperature Tam input in step 110 is determined to be compared with the first predetermined values (T3 and T4) and the second predetermined values (T1 and T2) based on the characteristic line shown in FIG. 4 in step 120. Based on the outside air temperature Tam, the load is high when it is higher than the first predetermined value, and is medium load when it is higher than the second predetermined value and smaller than the first predetermined value, and is equal to or lower than the second predetermined value. In this case, the load is determined to be low. In this embodiment, the outside air temperature Tam is used as a judgment factor to determine the environmental load. However, at least the outside air temperature Tam, the vehicle interior temperature Tinc, and the set temperature T
target blowing temperature XM calculated from set and solar radiation Qsun
Alternatively, the determination may be made based on the total signal T.

When it is determined that the load is high or the load is low based on the above-described determination, the expansion valve characteristic B (B characteristic) is set and the load is medium. Is determined, the expansion valve characteristic A (A characteristic)
Is set. In addition, as shown in FIG.
Is a characteristic in which the degree of superheat is set to be larger than the saturated vapor pressure characteristic ULs of the refrigerant, and the expansion valve characteristic B is a characteristic in which the degree of superheat is set to be smaller than the saturated vapor pressure characteristic ULs of the refrigerant. It is.

Then, in step 130, it is determined whether or not the expansion valve characteristic is B. If the B characteristic is set in step 120, the stepping motor (SM) 44 causes the adjustment nut 43 to move the adjusting nut 43 to the coil spring in step 140. By moving the coil spring 41 in the direction in which it expands, the urging force SPpw of the coil spring 41 is reduced. When the A characteristic is set in step 120, the process proceeds to step 150, in which the stepping motor (SM) 44 moves the adjusting nut 43 in a direction in which the coil spring 41 is reduced to increase the urging force SPpw of the coil spring 41. . And step 1
From 70, the process returns to the main control routine of the air conditioning control. Accordingly, when the urging force of the coil spring 41 is set to be small, the valve is easily opened, the amount of refrigerant flowing through the evaporator 7 increases, and the degree of superheat is reduced, so that the B characteristic is obtained. On the other hand, when the urging force of the coil spring 41 is increased, the valve is easily closed, so that the amount of refrigerant flowing through the evaporator 7 is reduced, the degree of superheat is increased, and the A characteristic is obtained.

As shown in FIG. 5, the air volume control according to the present invention, which is started from step 200, is periodically started from the main control routine similarly to the above-described expansion valve characteristic control. Ventilation volume setting device 5
7, it is determined whether or not the air volume is manually set. If the air volume is set manually, the process proceeds to step 220, where the air volume setting Fpm is manually set.
Is set. As shown in FIG. 6, in the manual (MANUAL) control, it is determined in step 221 whether or not the first speed is set, and if it is the first speed, the flow rate setting Fpm is set to 20% (step 222) as the low speed operation mode. LO) is set. Also,
If it is not the first speed, the process proceeds to step 223 to determine whether or not it is the second speed. If it is the second speed, in step 224, the air volume setting Fpm is set to 45% (ML) as the middle-low speed operation mode. Further, if not the second speed, step 22
The program proceeds to 5 to determine whether or not the vehicle is in the third speed. If the vehicle is in the third speed, the air flow rate setting Fpm is set to 64% (MH) as the medium / high speed operation mode in step 226. Assuming that the fourth speed is set, the flow rate setting Fpm is set to 100% (HI) in the high-speed operation mode in step 227. Then, returning to FIG. 5 from step 228, the Fpm is assigned to the blower control factor Fp in step 230, and the blower control factor Fp is set in the blower control signal Fpout in step 330. And step 3
From 40, the process returns to the main control routine.

If the air volume is not manually set in step 210 (AUTO),
Proceeding to step 240, it is determined whether or not the blowing mode is the vent blowing mode (VENT) (VENT?). Then, in the case of the vent blowing mode, in step 250, it is determined whether or not the blower 6 is under startup control (FAN).
It is determined that the startup control is being performed. If the startup control is being performed, the process proceeds to step 260, where the FAN startup control shown in FIG. 7 is executed.

FAN started from step 260
In the startup control, in step 261, it is determined whether or not the evaporator wake-side temperature Tint is greater than, for example, 35 ° C. In this determination, the evaporator wake-side temperature Tin
If t is equal to or lower than 35 ° C., it is determined that the FAN activation control is not required, and the process proceeds to step 270 shown in FIG. If it is determined in step 261 that the downstream temperature Tint of the evaporator is greater than 35 ° C., the process proceeds to step 262, where the operating state of the compressor 21 is determined. In this determination, when it is determined that the compressor 21 is not operating (N), the process proceeds to step 265 and the normal cooling start control A of the blower 6 is performed.
Is executed. The cooling start control A is performed at a predetermined rate ΔFpd1 (for example, 8% / sec) from a minimum air flow rate of 24% during automatic operation to a target air flow rate set by the target outlet temperature XM.
And controls the blower 6 so that the air volume increases.

If it is determined in step 262 that the compressor 21 is operating (Y), the flow advances to step 263 to determine whether the current expansion valve characteristic is the A characteristic or the B characteristic. It is determined whether or not the blower 6 has been selected (expansion valve characteristic?). If it is determined that the A characteristic has been selected, the operation of the blower 6 is delayed for t1 seconds (for example, 3 seconds) in step 264, and then the step At 265, the normal cooling start control A is performed as described above. If it is determined in step 263 that the B characteristic has been selected, the process proceeds to step 266, where the blower 6 is operated for t2 seconds (t2> t1: for example, 6 seconds).
, The cooling start control B is executed in step 267. The cooling start control B has an increase amount ΔF smaller than the increase amount ΔFpd1 of the cooling start control A described above.
pd2 (ΔFpd2 <ΔFpd1: for example, 4% / se
In c), the airflow is increased from the minimum airflow of 24% during automatic operation to the target airflow. As described above, when the environmental load is large and the B characteristic is selected, the stop time until the start of the operation of the blower is set longer than the normal case, and the increase amount to the target air volume is set smaller than the normal case. By
This can promote a decrease in the blowing temperature. Then, the process proceeds from step 268 to step 270 in FIG.

In step 270, the operating condition of the compressor 21 is determined again, and in the determination in step 280, it is determined whether the current expansion valve characteristic is the A characteristic or the B characteristic. In the determinations in steps 270 and 280, if the compressor 21 is stopped or if the compressor 21 is operating and the expansion valve characteristic is the A characteristic, the process proceeds to step 300 and the air blowing control shown in FIG. A is selected. On the other hand, the compressor 21
Operates and the expansion valve characteristic is the B characteristic, the routine proceeds to step 290, where it is determined whether or not the outside air temperature Tam is higher than a predetermined value T15 (for example, 25 ° C.). Is determined to be the one set at the time of high load, and if the B characteristic is set at the time of high load, the routine proceeds to step 310, where the blowing control B shown in FIG. 9B is selected. If it is determined in step 290 that the B characteristic is not at the time of high load, step 340 is executed.
To return to the main control routine. In addition, air volume control B
Restricts the maximum value of the air volume on the cooling side to 80%,
The starting point of the airflow rise is moved to the cooling side, and the airflow on the cooling side is suppressed as a whole.

Thus, steps 300 and 310
, The air flow rate F at the time of automatic operation from the target outlet temperature XM
pa is set, and in step 320, the blower control factor Fp
The fan control factor Fp is set in the fan control signal Fpout in step 330. Then, the process returns from step 340 to the main control routine. As described above, at the time of a high load in which the B characteristic is selected as the expansion valve characteristic, the airflow control B is selected to suppress the air volume during the cooling operation, so that the temperature decrease of the evaporator 7 is promoted. Can be accelerated, and can cope with rapid cool down.
In addition, even when the environmental load fluctuates and the expansion valve characteristic changes from the A characteristic to the B characteristic, the blown air amount is suppressed, so that the temperature of the blown air can be reduced earlier.

In the case of an idle stop vehicle, the compressor 21 stops simultaneously with the idle stop.
It is preferable to execute the air volume control as shown in FIG.
In the air flow control at the time of idling stop started from step 400, it is determined in step 410 whether or not the idling stop operation is performed. In this determination, when it is determined that the operation is not the idling stop operation, step 420
In FIG. 9, the normal air volume control A shown in FIG. 9A is selected. When it is determined that the engine is in the idling stop operation, the process proceeds to step 430, where the expansion valve characteristic is determined.
The process proceeds to 0, and the air volume control C shown in FIG. 9C is selected.
In the air volume control C, the maximum value of the air volume is limited to 40%, and the temperature rise of the evaporator 7 is suppressed to some extent.

If it is determined in step 430 that the characteristic is the B characteristic, the process proceeds to step 45.
Proceeding to 0, the air volume control D is selected. This air volume control D
Is to fix the air flow not to the minimum air flow at the time of automatic operation but to the LO air flow at the time of manual setting so as to minimize the temperature rise of the evaporator 7.

Then, steps 420, 430 or 45
At 0, the air flow rate Fpa during automatic operation is set from the target blowout temperature XM, at step 460 the Fpa is assigned to the blower control factor Fp, and at step 470 the blower control factor Fp is set at the blower control signal Fpout. You. Then, the process returns from step 480 to the main control routine.

The compressor control according to the present invention, which is started from step 500, uses a variable displacement compressor as the compressor 21, and is periodically started from the main control routine similarly to the above-described expansion valve characteristic control. You. Then, in step 502, the air volume is manually set by the air volume setting device 57, or
It is determined whether or not a blower operation instruction signal for driving the blower is output (FANON?) So that the blower 6 is automatically driven by the UTO control, and the blower operation instruction signal for driving the blower 6 is output. If not (N)
Go to step 520 to set the compressor off mode (COMP OFF MODE)
From 22, the program returns to the main control routine. If the blower operation instruction signal has been output (Y), the routine proceeds to step 504, where it is determined whether the compressor operation instruction signal has been output (COMPON?). FIG.
1 shows a flowchart in the case where a compressor having a fixed capacity is used.

If it is determined in step 504 that the compressor operation instruction signal has been output, the flow advances to step 506 to determine the outside air temperature as shown in FIG. In this determination, the normal T
5 is set to −2 ° C., and T6 is set to + 1 ° C. When the compressor 21 has a fixed capacity, seizure due to deterioration of lubrication oil return when the capacity becomes low at low outside air temperature is prevented. Therefore, even if it is determined in step 504 that the compressor operation instruction signal is output, if the outside air temperature Tam is lower than T5 (C), the process proceeds to step 520 to set the compressor off mode. Things.

If the determinations in steps 502, 504, and 506 are cleared, the routine proceeds to step 508, where it is determined whether or not the expansion valve characteristic is the B characteristic. If it is the A characteristic, the process proceeds to step 512. In step 510, FIG.
It is determined whether the B characteristic selected according to the characteristic line shown in (b) is selected by high load or by low load. Normally, T7 is 10
C. and T8 are preferably 12 ° C.

If it is determined in step 508 that the A-characteristic is set, the routine proceeds to step 512, where it is determined whether or not the engine is in the idle stop mode (IS MODE?). Proceeding to step 514, the target evaporator downstream temperature Ti
T13 (for example, 3 ° C.) is set to ntC. Also,
When it is determined in step 510 that the B characteristic is due to a low load (E) or step 51
If the idle stop mode is set in the determination of step 2, the routine proceeds to step 516, where T14 (for example, 1 ° C.) is set as the target evaporator wake-side temperature TintC. The discharge capacity is set so as to increase. Then, in step 518, the compressor ON mode (COMP ON
MODE) is set, and the routine returns from step 522 to the main control routine.

As described above, when the environmental load is low, B
By controlling the expansion valve according to the characteristics and increasing the discharge capacity of the compressor, control is performed so as to increase the circulation amount of the refrigerant, and lubricating oil remaining in the refrigeration cycle is returned to the compressor 21. Is to prevent burn-in. In the above-described embodiment, as means for increasing the discharge capacity of the compressor,
Although the method of raising the target evaporator wake side temperature TintC is used, the low pressure Ps is set lower than usual, or the method of controlling the variable capacity mechanism of the compressor such that the capacity is directly increased. Is also good.

The flowchart shown in FIG. 11 shows the control when a compressor having a fixed capacity is used as the compressor 21. The main control is performed in the same manner as the expansion valve characteristic control and the compressor control shown in FIG. Initiated periodically from the routine. Then, in step 602, it is determined whether the air volume is manually set by the air volume setting device 57 or a blower operation instruction signal for driving the air blower is output so that the air blower 6 is automatically driven by the AUTO control. (FANON?) Is determined, and if the blower operation instruction signal for driving the blower 6 is not output (N), the process proceeds to step 626 and the compressor is turned off (COMP OFF MODE).
Is set, and the process returns from step 628 to the main control routine. If the blower operation instruction signal has been output (Y), the routine proceeds to step 604, where it is determined whether the compressor operation instruction signal has been output (COMPON?).

If it is determined in step 604 that the compressor operation instruction signal has been output, the flow advances to step 606 to determine whether or not the expansion valve characteristic is the B characteristic. Step 6 in case
08, if it is the A characteristic, the process proceeds to step 610.
Note that in this flowchart, the compressor 21
Is a fixed displacement type, and unlike the variable displacement compressor control shown in FIG. 10, the displacement becomes low at a low load, and no seizure occurs due to the deterioration of the return of the lubricating oil. It is not necessary to perform the outside air temperature determination as shown.

Then, in step 608, FIG.
It is determined whether the B characteristic selected according to the characteristic line shown in (b) is selected by high load or by low load. Normally, T7 is 10
C. and T8 are preferably 12 ° C. If it is determined in step 606 that the characteristic is the A characteristic, the process proceeds to step 610 to determine whether or not the engine is in the idle stop mode (IS MODE?). Go ahead, Figure 1
In the clutch control determination 1 shown in FIG.

In the determination at step 612, for example, T9 is set to 2 ° C. and T10 is set to 4 ° C. If the downstream temperature Tint of the evaporator is lower than T9, G is selected, and the program proceeds to step 616 to proceed to step 616. Is turned off (CL OFF), and if it is higher than T10, H is selected and the routine proceeds to step 618, where the electromagnetic clutch 51 is turned on (CL ON).

If it is determined in step 608 that the B characteristic is due to a low load (E) or if the idle stop mode is set in step 610, step 614 is performed.
Then, in the clutch control determination 2 shown in FIG.

In the determination in step 614, for example, T11 is set to 0 ° C. and T12 is set to 2 ° C. If the downstream side temperature Tint of the evaporator is lower than T11, J is selected and the routine proceeds to step 620, where the electromagnetic clutch 51 is set. Is turned off (CL OFF), and if it is higher than T12, K is selected and the routine proceeds to step 622, where the electromagnetic clutch 5 is turned off.
1 is turned on (CL ON), and the compressor 21 is set to a state in which the compressor 21 is easier to drive than the clutch control determination 1 described above.
MP ON MODE) is set, and the routine returns from step 628 to the main control routine.

In the above embodiment of the present invention, the expansion valve characteristic is set to the A characteristic and the B characteristic.
The characteristics may be changed linearly, and the air volume control may be changed linearly in response to the change.

[0055]

As described above, according to the present invention, when the expansion valve is operated with a characteristic that the environmental load is large and the degree of superheat is reduced at the time of starting the cooling, the stop time of the blower is lengthened and the blower is cooled. Since the rate of increase of the air volume is set lower than in the normal case, it is possible to promote a decrease in the blow-out temperature and to obtain a good air-conditioning state. Also, even during normal operation, when the operation state of the expansion valve changes from the characteristic of setting the superheat degree to the characteristic of decreasing the superheat degree, the air flow during the cooling operation is limited, so that the blowout temperature is reduced. Reduction can be promoted, and a good air-conditioning state can be obtained in the same manner as described above.

In the idle stop operation mode,
When the expansion valve is operating with a characteristic of a small degree of superheat and the compressor is stopped, the amount of air blown is significantly limited, and the temperature rise of the evaporator can be suppressed, so that the air conditioning condition is improved. Can be maintained.

When the load is further reduced, the compressor discharge amount is set to be large at the same time as the B characteristic is selected, so that the amount of circulating refrigerant can be increased. The amount of lubricating oil to be lubricated can be secured.

Further, in the idle stop operation mode, B
Even when the characteristic is selected, the discharge amount of the compressor is increased, so the circulation amount of the refrigerant increases,
Even in the intermittent operation of the compressor, the cooling power of the evaporator can be improved.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of the expansion valve according to the embodiment of the present invention.

FIG. 3 is a flowchart for setting expansion valve characteristics according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram for setting expansion valve characteristics from outside air temperature.

FIG. 5 is a flowchart showing a basic control routine of air volume control according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a manual control routine of air volume control.

FIG. 7 is a flowchart illustrating a FAN activation control routine according to the embodiment of the present invention.

FIG. 8 is a flowchart showing air volume control during idle stop operation according to the embodiment of the present invention.

9A is a blow control A, FIG. 9B is a blow control B, FIG.
(C) is an explanatory diagram showing the air blowing control C, and (d) is an explanatory diagram showing the air blowing control D.

FIG. 10 is a flowchart illustrating compressor control when the variable displacement compressor according to the embodiment of the present invention is used.

FIG. 11 is a flowchart illustrating compressor control when a fixed displacement compressor according to an embodiment of the present invention is used.

12A is a characteristic diagram showing outside air determination, and FIG. 12B is a characteristic diagram showing low load operation determination.

13A and 13B are characteristic diagrams for performing on / off determination of a fixed displacement compressor, wherein FIG. 13A shows a clutch control determination 1 and FIG.
FIG. 7 is a characteristic diagram showing clutch control determination 2.

FIG. 14 is a characteristic diagram showing the A characteristic and the B characteristic of the expansion valve.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 air conditioner for vehicle 2 air conditioning duct 3 outside air inlet 4 inside air inlet 5 intake door 6 blower 7 evaporator 8 heater core 9 air mix door 20 refrigeration cycle 21 compressor 22 capacitor 23 gas-liquid separator 30 expansion valve 39 valve body 41 coil spring 43 Adjustment nut 44 Motor

Claims (10)

[Claims] 1. A refrigerating cycle is constituted together with an evaporator disposed in an air conditioning duct, an opening degree adjusting means for adjusting a position of a valve element by a refrigerant temperature and a pressure at an outlet side of the evaporator, and a direction for closing the valve element. And an expansion valve having an urging force adjusting means for adjusting the urging force of the urging means, and a blower and a refrigeration cycle arranged at least in an air conditioning duct as air conditioning control equipment. In a vehicle air conditioner having a compressor constituting a part thereof, an environmental load detecting means for detecting an environmental load of the refrigeration cycle, and controlling the urging force adjusting means according to the environmental load detected by the environmental load detecting means. Urging force control means, and air conditioning control means for controlling the air conditioning control device in accordance with the urging force of the urging means controlled by the urging force control means. An air conditioner for a vehicle, comprising: 2. The urging force control means includes a urging force in a low superheat degree control state in which at least the urging force of the urging means is reduced, and a high superheat degree control state in which the urging force of the urging means is increased. The vehicle air conditioner according to claim 1, wherein the control unit controls the adjusting unit. 3. The high-load determining means for determining whether the environmental load detected by the environmental load detecting means is greater than a first predetermined value; In the case of a high load larger than the predetermined value of 1, the urging force adjusting means is controlled to bring the urging means into a low superheat degree control state, and when the environmental load is a low load smaller than the first predetermined value. 3. The vehicle air conditioner according to claim 2, wherein the biasing force adjusting means is controlled to drive the biasing means to a high superheat degree control state. 4. The system according to claim 1, wherein said urging force control means further comprises: an environmental load detected by said environmental load detecting means.
A low load determining unit that determines whether the environmental load is smaller than a second predetermined value that is smaller than a predetermined value, wherein the environmental load is a high load that is larger than the first predetermined value, and When the load is lower than a predetermined value, the urging force adjusting means is controlled to bring the urging means into a low superheat degree control state, and the environmental load is smaller than the first predetermined value and the second 4. The vehicle air conditioner according to claim 3, wherein when the load is a medium load larger than a predetermined value, the urging force adjusting means is controlled to bring the urging means into a high superheat degree control state. 5. The air-conditioning control means includes a blower control means, and the blower control means sets the urging means to a high level when the urging means is in a low superheat degree control state at the time of starting the refrigerant. 5. The air conditioner according to claim 3, further comprising: increasing a stop time of the blower at an initial stage of startup and reducing a rate of increase in a rotation speed of the blower, as compared to a case in a superheat degree state.
An air conditioner for a vehicle as described in the above. 6. The vehicle according to claim 5, wherein at the time of cool-down, the blower control means reduces the air volume of the blower when the urging means is in a low superheat state. Air conditioner. 7. The air blower control means reduces the air flow during idling stop and reduces the air flow when the urging means is in a low superheat state and the air flow when the urging means is in a high superheat state. The vehicle air conditioner according to claim 5, wherein the air conditioner is set to be smaller than the air conditioner. 8. The biasing force control unit includes a low load determining unit that determines whether an environmental load detected by the environmental load detecting unit is smaller than a second predetermined value. In the case of a low load smaller than the second predetermined value, the urging force adjusting means is controlled to set the urging means in a low superheat degree control state, and the environmental load is set to a medium load larger than the second predetermined value. 3. The air conditioner for a vehicle according to claim 2, wherein in the case, the urging force adjusting means is controlled to bring the urging means into a high superheat degree control state. 9. The air-conditioning control means includes a compressor control means, wherein the compressor control means is configured to operate when the environmental load is lower than the second predetermined value and the urging means is in a low superheat degree control state. The air conditioner for a vehicle according to any one of claims 4 to 8, wherein the discharge amount of the compressor is increased in the case. 10. The compressor control unit according to claim 4, wherein the compressor control unit increases the discharge amount of the compressor when the urging unit is in a low superheat degree control state at idle stop. The vehicle air conditioner according to one of the above aspects.