JPH1038717A - Variable capacity compressor torque-detecting method of air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the torque of a variable capacity compressor of an air conditioner for a vehicle. SOLUTION: When meteorological condition such as outside air temperature is measured (step 100), post-evaporator temperature is determined on the basis of the measured result and the set temperature in a vehicle room (step 102). From the post-evaporator temperature, the set pressure of a control valve is operated, and a flowing current to a solenoid is set to obtain the set pressure (steps 104, 106). From the set current and the meteorological condition such as outside air temperature, compressor torque is operated. On the basis of the operated result, ISCV is controlled, and the number of revolution of an engine is kept almost constant (step 108, 110).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner provided with a variable capacity compressor for controlling air in a vehicle cabin, and more particularly to a vehicle air conditioner for controlling the engine speed of a vehicle. The present invention relates to a method for detecting a variable displacement compressor torque of a device.

[0002]

2. Description of the Related Art There is a vehicle air conditioner which uses a variable displacement compressor for power saving to achieve air conditioning in a vehicle. There are two types of control of the variable capacity compressor, one of which is a refrigerant supplied to the evaporator so that the temperature of the air passing through the evaporator (the temperature after the evaporator) becomes 2 ° C. to 3 ° C. so that the frost does not occur in the evaporator. In this method, the pressure is controlled so that the pressure, that is, the suction pressure of the compressor, becomes substantially constant around a predetermined value (for example, 3 kg / cm ² ). Also. Another method is to change the air temperature after the evaporator according to weather conditions, such as by increasing the temperature of the air passing through the evaporator when the cooling load is relatively small and controlling the compressor capacity to be small. In other words, this is a method of controlling the capacity so as to save power by changing the refrigerant pressure of the evaporator, that is, the suction pressure of the compressor, to control the capacity to be smaller.

For this purpose, in the former method, a valve mechanism for controlling the suction pressure of the compressor to be substantially constant is provided, and in the latter method, a pressure control in which a solenoid is added in addition to the valve mechanism is provided. A valve is provided to change the suction pressure of the compressor by increasing or decreasing the current supplied to the solenoid.

For example, in a wobble plate type variable displacement compressor, a valve element such as a ball valve biased by a coil spring or the like is moved by driving a solenoid. At this time, if a large amount of refrigerant flows into the control pressure chamber of the compressor by increasing the amount of movement of the ball valve (valve element) by increasing the energizing current (solenoid current) to the solenoid, the stroke of the piston is reduced. It becomes shorter, the discharge amount decreases, and the suction pressure of the compressor rises. Further, by reducing the solenoid current or setting the solenoid to a non-energized state, the refrigerant is pushed out from the control pressure chamber of the compressor, and the stroke of the piston is lengthened. Thus, the discharge amount is increased and the suction pressure of the compressor is reduced.

In addition, the pressure of the refrigerant in the crank chamber is adjusted by moving a ball valve by driving a solenoid, thereby changing the stroke of a piston and adjusting the suction pressure of a compressor. For example, it is common to adjust the suction pressure by applying a current to a solenoid.

In a vehicle air conditioner, by changing the suction pressure of such a compressor, the refrigerant pressure of the evaporator changes, so that the temperature of the air passing through the evaporator can be changed and the driving torque of the compressor can be changed. be able to. For example, when the outside air temperature is low and the cooling load is small, if the capacity of the compressor is reduced by increasing the suction pressure of the compressor, the power saving and the air conditioning efficiency can be improved.

In a vehicle air conditioner, a variable displacement compressor is driven by the rotational force of an engine. In a variable displacement compressor, the drive torque also changes by changing the compressor displacement. For this reason, when the engine of the vehicle is in a low output state, for example, at the time of idling, the driving torque of the variable displacement compressor changes, and when the engine load changes, the engine speed also changes. Changes in the engine speed of the vehicle while the vehicle is stopped or running at a low speed may cause discomfort to the occupant of the vehicle.

In recent years, in order to solve such a problem,
For a variable displacement compressor with a constant suction pressure (constant temperature after evaporator), the discharge pressure of the variable displacement compressor is detected by a pressure sensor, and the engine speed during idling is controlled based on the compressor torque calculated from the detection result. There's something we did. As a result, even if the drive torque of the variable displacement compressor changes during low output of the engine during idling or the like, it is possible to prevent the change in the engine speed due to the change in the drive torque.

The detection of the change in the driving torque of the variable displacement compressor using the pressure sensor will be briefly described. The refrigerant discharge amount Gr of the compressor of the compressor, the compressor suction pressure Ps, the suction refrigerant specific volume Vs, the compressor discharge pressure P
From d and the polytropic coefficient n, the compression work L of the compressor is expressed by the following equation (1).

[0010]

(Equation 1)

Here, the refrigerant discharge amount Gr is expressed by equation (2) based on the volume efficiency η _{v and the} compressor volume (variable) Vc and the compressor rotation speed Nc.

[0012]

(Equation 2)

If the compressor suction pressure Ps is substantially constant at the set pressure, the suction refrigerant specific volume Vs is also substantially constant, and the product of the volume efficiency η _v and the compressor volume Vc is mainly the product of the compressor discharge pressure Pd and the compressor suction pressure Ps. Function
Since the compressor suction pressure Ps is constant, it becomes a function of the compressor discharge pressure Pd, and the equations (3) and (4) are derived.

Here, the compressor torque T is expressed as follows from the mechanical efficiency η _m and the compressor power Lc.

[0015]

(Equation 3)

That is, the compressor torque T is represented by a function of the compressor discharge pressure Pd, and the compressor torque T can be obtained by measuring the compressor discharge pressure Pd with a pressure sensor.

[0017]

However, such calculation of the compressor torque T is performed by setting the suction pressure Ps of the compressor to a substantially constant set value (for example, 3 kg / cm ² AB).
This is a case in which the evaporator does not frost before and after S). For this reason, when the suction pressure of the compressor changes, the detection accuracy of the compressor torque deteriorates.

That is, if the compressor suction pressure is a set value, the accuracy of detecting the compressor torque is high. However, if the compressor suction pressure deviates from the set value, the accuracy of the torque detection deteriorates, and the engine rotation due to a change in the compressor torque is reduced. It may be difficult to suppress the change in number.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has a high accuracy in detecting the torque of a variable displacement compressor even in displacement control in which the suction pressure of the compressor is changed according to weather conditions. An object of the present invention is to propose a method for detecting a variable displacement compressor torque of a device.

[0020]

According to the present invention, there is provided a vehicle air conditioner in which a refrigerating cycle is formed including an evaporator, a condenser and a variable capacity compressor, and a temperature after the evaporator is determined according to weather conditions. Evaporator post-temperature determining means, evaporator set pressure calculating means for determining the evaporator set pressure based on the determined evaporator temperature, and energizing current to a solenoid for setting the suction pressure of the compressor to be the set evaporator pressure. A variable capacity compressor torque detecting method for a vehicle air conditioner having a solenoid current setting means for determining, wherein a variable capacity compressor torque is calculated based on the set solenoid current and an outside air temperature affecting the condenser capacity. , Characterized in that.

According to the present invention, the compressor torque is calculated based on the current supplied to the solenoid for adjusting the suction pressure of the variable capacity compressor and the outside air temperature affecting the capacity of the condenser.

When idling or running at low speed, in which a change in the compressor torque greatly appears due to a change in the engine load, the amount of air passing through the condenser is substantially constant, so the refrigerant pressure (compressor discharge pressure) Pd in the condenser
Is higher as the refrigerant discharge pressure Gr is higher and the outside air temperature is higher. Therefore, as shown in the equation (6), the refrigerant pressure Pd
Can be expressed as a function of the refrigerant discharge pressure Gr and the outside air temperature.

Further, as shown in the equation (7), the specific volume Vs of the compressor suction of the refrigerant can be substantially expressed as a function of the suction pressure Ps. From this, the equations (2 ') and (8) show that 8 ′) is obtained. Furthermore, the expression (8 ′) and (2 ′)
Equation (9) is obtained by substituting equation (7) into equation (1 ′).

From the above, when the outside air temperature is T ₀ , the compressor compression work L is a function of the compressor suction pressure Ps and the outside air temperature T ₀ (see the equation (9)). Further, the compressor suction pressure Ps varies depending on the current supplied to the solenoid, and can be expressed as a function of the solenoid current Ic. Therefore, the variable displacement compressor torque T can be accurately obtained by calculation as a function of the outside air temperature T ₀ and the solenoid current Ic (see equation (11)).

[0025]

(Equation 4)

By accurately calculating (detecting with high precision) the variable displacement compressor torque and controlling the engine based on the detection result of the variable displacement compressor torque, the drive torque of the variable displacement compressor changes during idling. Even so, the engine speed does not change and the occupant does not feel uncomfortable.

When setting the compressor capacity, various weather conditions may be considered in addition to the outside air temperature. Further, when the condenser is cooled by an electric fan or the like, it may be calculated in consideration of the cooling efficiency of the electric fan (for example, the rotation speed of the electric fan or the voltage applied to the electric fan) in addition to the weather conditions including the outside air temperature. good.

[0028]

FIG. 1 shows a schematic configuration of a vehicle air conditioner (hereinafter referred to as "air conditioner 10") applied to the present embodiment. The air conditioner 10 includes a variable displacement compressor (hereinafter referred to as a “compressor 14”) driven by transmitting torque (for example, transmitted by a pulley and a belt) of an engine 12 of a vehicle, and a condenser 1.
6. Expansion valve 18 and damper unit 2
The refrigeration unit 24 includes a refrigeration cycle constituted by an evaporator 22 and the like arranged in the inside of the refrigeration cycle.

In the refrigeration unit 24, the refrigerant compressed to a high pressure by the compressor 14 is decompressed and vaporized when passing through the evaporator 22, thereby cooling the air in the damper unit 20 passing through the evaporator 22. At this time, the temperature of the air that has passed through the evaporator 22 (the temperature after the evaporator) can be changed by changing the capacity of the compressor 14 and changing the compressor suction pressure. That is, in the refrigeration unit 24, the post-evaporator temperature can be set by the compressor suction pressure of the compressor 14.

A blower fan is provided in the damper unit 20, and the air or the outside air in the vehicle compartment is sucked by the blower fan and sent to the evaporator 22. When the temperature of the air passing through the evaporator 22 is adjusted to a predetermined temperature by, for example, a temperature control unit (for example, a heating unit) (not shown), the air is blown out from a defroster, a vent, or a heater outlet into the vehicle interior, and the interior of the vehicle interior is set to a desired setting. The temperature is maintained.

FIG. 2 shows a wobble plate type compressor as an example of the compressor 14. In the compressor 14, a drive shaft 30 connected to the engine 12 via an electromagnetic clutch (not shown) is inserted into a casing 32, and is supported rotatably. This drive shaft 30
, A wobble plate 34 is connected via a hinge ball 36.

The wobble plate 34 is a casing 32
The swing shaft is swingably connected to the drive shaft 30 around the hinge ball 36 as a fulcrum in a crank chamber 38 formed therein, and rotates integrally with the drive shaft 30. The wobble plate 34 has a piston 4 reciprocating in the cylinder 40.
2 are installed. This piston 42 is connected to the drive shaft 3
The cylinder 40 reciprocates by rotating the wobble plate 34 inclined with respect to zero. At this time, the stroke changes according to the inclination angle of the wobble plate 34 with respect to the drive shaft 30.

The compressor 14 is provided with a control valve 44. The control valve 44 includes a valve body 48 disposed so as to close an opening provided between the crank chamber 38 and a suction chamber 46 provided on the refrigerant suction side of the compressor 14. By moving the body 48, the communication state between the suction chamber 46 and the crank chamber 38 changes. The suction chamber 46 communicates with a suction chamber 50 adjacent to the cylinder 40.

The valve body 38 is provided on the plunger 54 of the solenoid 52. By changing the current supplied to the solenoid 52, the valve body 38 moves in the direction of arrow A against the urging force of a coil spring (not shown). , And moves in the direction opposite to the direction of arrow A by the urging force of the coil spring. In the control valve 44, the throttle between the suction chamber 46 and the crank chamber 38 is reduced by moving the valve body 38 in the direction of arrow A, and is greatly reduced by moving in the direction opposite to the direction of arrow A. .

That is, by controlling the current supplied to the solenoid 52, the crank chamber 38 is moved from between the piston 42 and the cylinder bore (the inner wall surface of the cylinder 40).
The amount of blow-by gas leaking into the suction chamber 46 can be adjusted. If the throttle is small, the return of the blow-by gas is reduced, and the pressure in the crank chamber 38 when the piston 42 returns is increased. Accordingly, the stroke of the piston 42 is shortened, and the ability to discharge the refrigerant from the compressor 14 is reduced (decreased).

For example, the solenoid 52 moves the valve element 48 together with the plunger 54 in a direction (a direction opposite to the direction indicated by the arrow A in FIG. 2) that narrows the communication between the crank chamber 38 and the suction chamber 46 when the energizing current decreases. As a result, the amount of blow-by gas returning from the crank chamber 38 to the suction chamber 46 decreases, and the pressure in the crank chamber 38 increases. Accordingly, the stroke of the piston 42 of the compressor 14 is reduced, and the compressor capacity (discharge amount) is reduced.

As described above, when the stroke of the piston 42 changes in accordance with the pressure in the crank chamber 38, the suction pressure to the cylinder 40, that is, the suction pressure of the compressor 14, changes in accordance with the stroke. Therefore, the compressor suction pressure can be adjusted by the control valve 44. In other words, in the air conditioner 10, the compressor suction pressure can be adjusted by the current supplied to the solenoid 52 of the control valve 44.

Note that the compressor 14 is an example of a variable displacement compressor using the solenoid 52, and does not limit the configuration of the variable displacement compressor of the air conditioner to which the present invention is applied. Various configurations such as moving the wobble plate along the axial direction of the drive shaft 30 can be applied to the variable displacement compressor. Further, the variable displacement compressor is not limited to the wobble plate type, but may be of another type such as a bypass type or a speed change type.

As shown in FIG. 1, the air conditioner 10
An air conditioning control circuit 60 having a microcomputer is provided. The air conditioning control circuit 60 controls the operation of the air conditioner 10 based on an operation mode and a set temperature set by operating an operation panel (not shown).

A solenoid 52 provided in the compressor 14 is connected to the air-conditioning control circuit 60, and the current of the solenoid 52 is controlled to control the performance of the compressor 14. Further, to the air conditioning control circuit 60, an outside air temperature sensor 64 for detecting an outside air temperature, a post-evaporator temperature sensor 66 for detecting a post-evaporator temperature, and the like are connected.

The air-conditioning control circuit 60 sets the post-evaporator temperature according to the outside air temperature when operating based on the set operation mode and the indoor temperature, and the compressor suction pressure according to the set post-evaporator temperature. The current supplied to the solenoid 52 is set so as to be obtained. As a result, a so-called power-saving operation is performed in which efficient air conditioning is performed and the load on the engine 12 is reduced by suppressing the capacity of the compressor.

On the other hand, the air conditioning control circuit 60 is provided with an engine control computer (hereinafter referred to as "ECC") for controlling the engine of the vehicle.
68 "). The ECC 68 is provided with a vehicle speed sensor 70, and outputs the running speed of the vehicle detected by the vehicle speed sensor 70 to the air conditioning control circuit 60.

The air-conditioning control circuit 60 calculates the driving torque of the compressor 14 based on the detection result of the vehicle speed sensor 70 which affects the capacity of the condenser, the outside air temperature, and the set current supplied to the solenoid 52 (only during low-speed running). The vehicle speed sensor 70 need not be used). Air conditioning control circuit 6
0 outputs this operation result to the ECC 68.

The ECC 68 is provided with a throttle valve 7 whose opening and closing angle changes by operating an accelerator pedal (not shown).
2 is connected to an idle speed control valve (hereinafter referred to as “ISCV74”). E
In CC68, for example, by controlling the ISCV 74 with the throttle valve closed, the engine speed during idling is kept substantially constant.

That is, the ECC 68 controls the ISCV 74 based on the compressor torque output from the air-conditioning control circuit 60 when the engine 12 is rotating at a low speed such as when idling. This prevents a change in the engine speed.

Next, the operation of the present embodiment will be described in detail. The flowchart of FIG. 3 shows the flow of the process of detecting the torque of the compressor 14 in association with the operation of the air conditioner 10, and will be described below with reference to this flowchart.

This flowchart is based on the engine 1 of the vehicle.
2 is started and the operation of the air conditioner 10 is started. In a first step 100, weather conditions around the vehicle are measured. At this time, at least the outside air temperature is measured as the weather condition to be measured.
However, in order to keep the interior of the vehicle in a comfortable air-conditioned state, the sunshine amount, the humidity, and the like may be measured together. These measurement results are also used as operating conditions when the air conditioning control circuit 60 operates the air conditioner 10.

In the next step 102, the post-evaporator temperature is determined based on the measured weather conditions, the operation mode of the air conditioner 10, and the set temperature in the vehicle compartment so that the air conditioner 10 operates efficiently. As is conventionally known, the post-evaporator temperature is determined to be higher when the outside air temperature is low, and to be lower when the outside air temperature is high. At this time, the post-evaporator temperature measured by the post-evaporator temperature sensor 66 may be determined to be a predetermined temperature.

Thereafter, in step 104, a compressor suction set pressure by the control valve 44 of the compressor 14 is calculated from the determined post-evaporator temperature.
The relationship between the post-evaporator temperature and the compressor suction set pressure is determined in advance.

The temperature after the evaporator is determined by the compressor 14
The suction pressure of the compressor 14 is determined by the control valve 44. That is, the control valve 44 is
By changing the restriction of the opening between the suction chamber 8 and the suction chamber 46, the pressure in the crank chamber 38 changes with the movement of the piston 42, and according to the pressure in the crank chamber 38,
The stroke of the piston 42 changes. This piston 42
Determines the suction pressure of the compressor 14.

In the next step 106, the current supplied to the solenoid 52 for adjusting the throttle of the control valve 44 is determined so that the compressor suction pressure is set to the set pressure by the control valve 44.

The solenoid 52 used for the control valve 44 is configured such that, for example, the energizing current is increased (increased) so that the valve body 48
6, the pressure in the crank chamber 38 can be reduced. However, by reducing (lowering) the current flow, the blow-by gas returning from the crank chamber 38 to the suction chamber 46 is narrowed. By reducing the amount, the pressure in the crank chamber 38 is increased (pressure drop is suppressed).

In this manner, the temperature after the evaporator is determined based on the weather conditions such as the outside air temperature, and the current supplied to the solenoid 52 of the control valve 44 is determined based on the temperature after the evaporator. The solenoid 52 is driven by this. Thereafter, in step 108, the compressor torque is calculated.

Here, the calculation of the driving torque (compressor torque) of the compressor 14 in the air conditioning control circuit 60 will be described in detail.

The compression work L of the compressor 14 is given by (1)
It can be represented by an equation. Further, the refrigerant discharge amount Gr can be expressed by equation (2). Here, the product of the volumetric efficiency η _v and the compressor volume Vc changes depending on the compressor suction pressure Ps and the compressor discharge pressure Pd. That is, the product of the volumetric efficiency η _v and the compressor volume Vc is
It is obtained as a function of the compressor suction pressure Ps and the compressor discharge pressure Pd (see equation (8)).

[0056]

(Equation 5)

On the other hand, the compressor discharge pressure Pd is determined by the refrigerant discharge amount Gr and the capacity (cooling capacity) of the condenser 14.

Here, when the engine is idling with the vehicle stopped, the vehicle speed is "0", the engine speed is the idling speed, and the cooling fan of the condenser 14 is also idling. The number of rotations is in accordance with the rotation. From this, the cooling capacity of the condenser 14 is determined by the refrigerant discharge pressure Gr and the outside air temperature T ₀ ,
Compressor discharge pressure Pd can be expressed as a function of the refrigerant discharge amount Gr and the outside air temperature T ₀ ((12) see formula). From this, volumetric efficiency η _v and compressor volume Vc
Is expressed as a function of the compressor suction pressure Pd, the refrigerant discharge amount Gr, and the outside air temperature T ₀ (see the equation (13)).

[0059]

(Equation 6)

From the equations (2) and (13), Gr / Nc obtained by dividing the refrigerant discharge pressure by the number of revolutions is expressed by the equation (14).

The suction refrigerant specific volume Vs is determined by the degree of superheat SH of the refrigerant discharged from the evaporator and the suction pressure Ps of the compressor.
And can be expressed as a function of the degree of superheat SH of the refrigerant and the compressor suction pressure Ps. Further, the degree of superheat SH of the refrigerant can be regarded as substantially constant, whereby
From the equation, the specific volume Vs of the suction refrigerant is equal to the compressor suction pressure Ps.
, The refrigerant discharge amount Gr
Is arranged in the equation (15) as a function of the compressor suction pressure Ps and the outside air temperature T ₀ .

Therefore, the compressor discharge pressure Pd is expressed as a function of the compressor suction pressure Ps and the outside air temperature T ₀ from the equations (12) and (15) (see the equation (16)). From the equation (1), the compression work L
Is divided by the rotation speed Nc, the compressor suction pressure P
s and a function of the outside air temperature T ₀ . The compressor power Lc divided by the mechanical efficiency ηm of the compressor 14 is also used as Lc / Nc obtained by dividing the compressor power Lc by the rotation speed Nc.
It can be seen that this is a function of the outside air temperature T ₀ (see equation (17)).

[0063]

(Equation 7)

Here, it can be seen that the compressor suction pressure Ps is a function determined by the solenoid energization current Is, and that the power Lc of the compressor is also a function of the solenoid energization current Is.

Therefore, as shown in the equation (20), the compressor torque T is equal to the energizing current Is of the solenoid 52.
And a function of the outside air temperature T ₀ . That is, the current Is supplied to the solenoid 52 and the outside air temperature T ₀
Can be used to calculate the compressor torque T.

[0066]

(Equation 8)

Based on this, the air conditioning control circuit 60 of the air conditioner 10 calculates the compressor torque T at step 108.

The compressor torque T calculated as described above is output to the ECC 68 in step 110.

The ECC 68 controls the ISCV 74 based on the compressor torque T so that the engine 12 is controlled regardless of the torque change of the compressor 14 of the air conditioner 10.
Is set to be substantially constant. That is, when the compressor torque T increases, the intake air amount is increased so that the rotation speed of the engine 12 does not decrease due to the load of the engine 12 which increases due to the increase of the compressor torque T. When the load on the engine 1
Control is performed so that the number of rotations of 2 does not increase.

As described above, the compressor torque T of the air conditioner 10 is determined based on the solenoid current Is that determines the compressor suction pressure Ps and the weather conditions such as the outside air temperature that determines the ability of the condenser 16 to affect the compressor discharge pressure Pd. Thus, the compressor torque T can be accurately detected even in the control of a variable displacement compressor in which the suction pressure of the compressor 14 is changed. Further, by controlling the engine speed based on the compressor torque T accurately detected as described above, for example, even at a low output such as when the engine is running at a low speed, the change in the compressor torque causes the engine speed to change. Can be prevented from changing, and the user does not feel discomfort due to the change in the engine speed.

In this embodiment, the ECC 68 outputs the detection result of the vehicle speed sensor 70 to the air conditioning control circuit 60. However, the ECC 68 outputs the detection result of the vehicle speed sensor 70 directly to the air conditioning control circuit 60. There may be.

In this embodiment, the air conditioning control circuit 6
0, the compressor torque T is calculated and output to the ECC 68. However, the present invention is not limited to this, and the air-conditioning control circuit 60 supplies the rotation speed Nc of the compressor 14 and the current I
By outputting operation information such as s, the EC 68 may calculate the compressor torque T and control the ISCV 74 based on these output results.

Further, in this embodiment, the engine 12
Although the calculation of the compressor torque T at the time of idling is described above, the calculation is not limited to this, and the calculation of the compressor torque T is also possible while the vehicle is running. In this case, since the cooling capacity of the condenser 16 changes depending on the vehicle running speed, the vehicle running speed detected by the vehicle speed sensor 70 is added to a variable (parameter), and the compressor torque T
May be calculated. When an electric motor is used as a cooling fan for cooling the condenser 16, the cooling effect of the electric cooling fan may be added to the parameter for calculating the compressor torque T in addition to the outside air temperature.

The present embodiment shows an example of the present invention, and includes a refrigeration unit 2 including a compressor 14.
The present invention is not limited to the configuration of the air conditioner 4 and the air conditioner 10 including the same, and the present invention is applied to torque detection of a variable displacement compressor of various vehicle air conditioners having a variable displacement compressor whose capacity is changed by a solenoid. Can be.

[0075]

As described above, according to the present invention, the drive torque of the variable displacement compressor is determined based on the current flowing through the solenoid of the variable displacement compressor and weather conditions such as the outside air temperature which affects the capacity of the condenser. Is calculated and calculated, so that accurate detection of the driving torque is possible. In addition, by accurately detecting the compressor drive torque and controlling the engine speed based on the detection result, it is possible to reliably prevent the engine speed from changing due to the change in the drive torque of the variable displacement compressor. Excellent effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a main part of an air conditioner of a vehicle applied to an embodiment.

FIG. 2 is a schematic configuration diagram illustrating an example of a variable displacement compressor.

FIG. 3 is a flowchart showing an example of a process flow of compressor torque detection according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 air conditioner (vehicle air conditioner) 12 engine 14 compressor (variable capacity compressor) 16 condenser 22 evaporator 44 control valve 52 solenoid 60 air conditioning control circuit 64 outside temperature sensor 68 ECC 70 vehicle speed sensor 74 ISCV

Claims (1)

[Claims] A refrigeration cycle is formed by an air conditioner for a vehicle including an evaporator, a condenser and a variable capacity compressor, and a post-evaporator temperature determining means for determining a post-evaporator temperature according to weather conditions, and based on the determined post-evaporator temperature. An evaporator set pressure calculating means for determining an evaporator set pressure, and a solenoid current setting means for determining an energizing current to a solenoid for setting a suction pressure of a compressor so as to become a set evaporator pressure, A variable capacity compressor torque detecting method for a vehicle air conditioner, comprising: calculating a variable capacity compressor torque based on a set outside current affecting the solenoid current and the capacity of the capacitor. Detection method.