JP3817328B2 - Variable capacity compressor controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a variable capacity compressor used in an automotive air conditioner.
[0002]
[Prior art]
Recently, variable capacity compressors that can change the refrigerant discharge capacity according to the required amount of cooling capacity to meet the needs for power saving for car air conditioners and comfort needs such as blowing air temperature change and shock reduction during compressor ON / OFF control Is becoming widespread. For example, taking a swash plate type variable displacement compressor as an example, the piston stroke is changed by continuously changing the inclination of the swash plate so that the displacement is continuously changed. In this case, if the inclination of the swash plate is large, the discharge amount is large (during maximum cooling), and if the inclination is small, the discharge amount is also small (during capacity control). As described above, since the refrigerant circulation amount decreases except during the maximum cooling, the required power of the compressor decreases.
[0003]
As a control method for changing the displacement in such a variable displacement compressor (for example, changing the inclination of the swash plate in the case of a swash plate type), conventionally, control is performed using a so-called mechanical control valve (MCV). It is common. This mechanical control valve is a valve (for example, a bellows type control valve) provided in the compressor body, and internally performs variable control of the capacity using the suction pressure of the compressor. For example, when a bellows type control valve is provided in a swash plate type variable displacement compressor, the compressor and the high pressure side that lead to the discharge side of the compressor due to the bellows contraction / expansion due to the change in the suction pressure of the compressor (the magnitude relationship with the set pressure) By opening and closing the low pressure side valve leading to the suction side, the pressure in the crankcase (control pressure) is controlled, and the balance of the pressure applied to the piston is changed to change the inclination of the swash plate. As a result, the discharge pressure changes, and therefore the suction pressure changes accordingly.
[0004]
FIG. 4 is a general characteristic diagram of the mechanical control valve. In general, a mechanical control valve has a refrigerant discharge capacity (inclination of a swash plate) based on the above operating principle so that the suction pressure Ps has the characteristics shown in the figure with respect to fluctuations in the cooling load (load on the air side). Control. Thereby, the compressor performance, that is, the cooling capacity corresponding to the cooling load (air load) is obtained, and the evaporator is prevented from being frozen by controlling the cooling capacity.
[0005]
[Problems to be solved by the invention]
However, in the variable displacement control of such a conventional variable displacement compressor, mechanical control based on the characteristics shown in FIG. It is impossible to perform complicated control for the purpose.
[0006]
For example, when starting an air conditioner, there is a strong need for power saving from the viewpoint of reducing the amount of NOx in the exhaust gas. In other words, if the air conditioner is started when the catalyst temperature is low at the time of starting the engine, the compressor torque at the time of starting is large, so the engine load may increase and the amount of exhaust gas (NOx amount, etc.) may also increase. It is desired to reduce the compressor torque (compressor load) at the time of starting the air conditioner, that is, to save power. From the viewpoint of energy saving, it is desired to reduce the compressor torque and save power not only when the air conditioner is activated but also in the cool down control when the temperature in the passenger compartment is not so high. However, since the conventional mechanical control is based on the characteristics shown in FIG. 4 as described above, such complicated control for the purpose of power saving cannot be performed.
[0007]
The present invention has been made paying attention to the above problems in variable displacement control of a variable displacement compressor, and an object of the present invention is to provide a variable displacement compressor control device capable of performing complex control for the purpose of power saving and the like. And
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, a first aspect of the present invention provides a variable displacement compressor control device that performs variable control of discharge capacity of a variable displacement compressor that constitutes a refrigeration cycle of an automotive air conditioner, based on an electric signal from the outside. Control means for controlling the control pressure for changing the discharge capacity of the variable capacity compressor; discharge pressure detection means for detecting the discharge pressure of the variable capacity compressor;Engine speed recognition means for recognizing the engine speed based on a signal transmitted from the engine control device, vehicle interior temperature detection means (13) for detecting the temperature in the vehicle interior, and the engine speed recognition means. Based on the engine speed and the vehicle interior temperature detected by the vehicle interior temperature detection means,Control means for calculating a discharge pressure target value necessary for reducing compressor torque and outputting an electric signal for controlling the control means so that the output of the discharge pressure detection means coincides with the target value. And
[0009]
  In the present invention, the control means is of an external variable control system in which the capacity is changed by controlling the control pressure based on an external electric signal, and finer control is possible. The discharge pressure detecting means detects the discharge pressure of the variable capacity compressor, and the control means isBased on the engine speed recognized by the engine speed recognition means and the actual vehicle interior temperature detected by the vehicle interior temperature detection means.A discharge pressure target value required for reducing the compressor torque is calculated, and an electric signal for controlling the control means is output so that the output of the discharge pressure detecting means coincides with the target value. Based on this electrical signal, the control means controls the control pressure for changing the discharge capacity of the variable capacity compressor. As a result, the discharge capacity of the variable capacity compressor changes, the discharge pressure approaches the target value, and the compressor torque is reduced. More specifically, since the compressor torque is greatly influenced by the ratio of the discharge pressure and the suction pressure (= discharge pressure / suction pressure), the compressor torque can be controlled by setting the target value low and controlling the discharge pressure. Can be reduced. In other words, the control means of the external variable control system is adopted, and the compressor torque is reduced by performing the control for making the discharge pressure coincide with the target value, so that power saving can be achieved.
[0010]
The invention according to claim 2 is the invention according to claim 1, further comprising catalyst temperature detecting means for detecting a temperature of the catalyst for purifying exhaust gas from the engine, and the control means is configured to detect the catalyst temperature. The control is performed when the output of the detection means is equal to or less than a predetermined value.
[0011]
In this invention, the catalyst temperature detection means detects the temperature of the catalyst for purifying the exhaust gas from the engine, and the control means controls the control when the output of the catalyst temperature detection means is below a predetermined value. That is, discharge pressure control for reducing compressor torque is performed. In this way, by performing the control when the temperature is equal to or lower than a predetermined temperature (predetermined value) at which the catalyst starts functioning, the load on the engine is reduced at the time of startup, and the amount of exhaust gas from the engine is reduced. (NOx amount, etc.) is also reduced.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a system configuration of a variable capacity compressor control device according to an embodiment of the present invention.
[0013]
This system has a refrigeration cycle 1 mounted on an automotive air conditioner (car air conditioner). The refrigeration cycle 1 is configured by connecting a variable capacity compressor 2, a condenser 3, a liquid tank 4, an expansion valve 5, an evaporator 6 and the like by piping and enclosing a refrigerant therein. The variable capacity compressor 2 is selectively driven by an engine (not shown) via a belt (not shown) and a magnet clutch 7 and sucks and compresses the low-temperature and low-pressure gas refrigerant evaporated by the evaporator 6 at the time of driving. The gas refrigerant is pumped to the condenser 3 and the refrigerant is repeatedly circulated through the condenser 3 and the evaporator 6. A condenser fan 8 is attached to the condenser 3, and the condenser 3 cools and condenses the high-temperature and high-pressure gas refrigerant sent from the compressor 2 by heat exchange with the cooling air supplied by the condenser fan 8. . A liquid tank 4 provided between the condenser 3 and the expansion valve 5 gas-liquid separates the refrigerant liquefied by the condenser 3 to temporarily store the liquid refrigerant, and sends only the liquid refrigerant to the expansion valve 5. In the case of a temperature-type expansion valve 5 that is generally used, the medium-temperature and high-pressure liquid refrigerant that has passed through the liquid tank 4 is decompressed and expanded to form a low-temperature and low-pressure mist-like refrigerant, and downstream of the evaporator 6. The refrigerant flow rate is adjusted so that the evaporation state of the refrigerant has an appropriate degree of superheat at the evaporator outlet by feedback of a temperature sensing cylinder (not shown) provided in FIG. The evaporator 6 evaporates the mist-like refrigerant liquefied by the condenser 3 and becomes low-temperature and low-pressure by the expansion valve 5, and causes the air sent by a blower fan (not shown) to flow outside to exchange heat with the mist-like refrigerant. As a result, the air blown into the passenger compartment is cooled and simultaneously dehumidified.
[0014]
The variable displacement compressor 2 is, for example, a swash plate type variable displacement compressor, and the inclination of the swash plate can be controlled from the outside by an electric signal (external variable control method). That is, the variable displacement compressor 2 has an electronically operated control valve (ECV) 9 such as an electromagnetic valve that can be externally controlled by an electric signal instead of the conventional mechanical control valve (MCV) as a control means. . For example, when a solenoid valve that communicates with the high pressure side is used as the ECV 9, the inside of the crankcase and the low pressure side communicate with each other through a passage having a predetermined opening, and the pressure in the crankcase escapes to the low pressure side. ing. Therefore, by controlling the pressure in the crankcase (control pressure) by turning on and off the solenoid valve 9 to introduce / shut off the high-pressure side pressure, the balance of the pressure applied to the piston is changed, and the inclination of the swash plate Thus, the discharge capacity of the compressor 2 can be controlled. At this time, for example, a duty signal having an appropriate value duty ratio calculated from an autoamplifier described later is applied to the electromagnetic valve 9 as an external electric signal. When it is necessary to reduce the capacity (tilt of the swash plate), a duty signal having a large duty ratio is given to increase the opening time of the solenoid valve 9 to increase the pressure in the crankcase (control pressure). When the capacity (tilt of the swash plate) needs to be increased, a duty signal having a small duty ratio is given to shorten the valve opening time of the solenoid valve 9 to reduce the pressure (control pressure) in the crankcase. Let
[0015]
The variable capacity compressor 2 is controlled by an autoamplifier 10 as control means. Here, only components necessary for control (hereinafter simply referred to as “torque reduction control”) for the purpose of power saving (compressor torque reduction) at the time of starting the engine (and the air conditioner) are illustrated. That is, the auto amplifier 10 includes an ignition switch 11 for starting the engine, an air conditioner switch 12 for operating the air conditioner by turning on the compressor 2, an inside air sensor 13 for detecting the temperature in the vehicle interior, and exhaust gas from the engine. A catalyst temperature sensor 14 as a catalyst temperature detecting means for detecting the temperature of the catalyst for purifying the catalyst, a high pressure side pressure sensor (high pressure transducer) 15 as a discharge pressure detecting means for detecting the discharge pressure of the variable capacity compressor 2, and the like. It is connected. The auto amplifier 10 receives an engine speed signal from an engine control device (not shown). The rotational speed of the compressor 2 can be recognized from the engine rotational speed signal. The catalyst temperature sensor 14 detects, for example, the temperature of the three-way catalyst for converting and reducing harmful components (HC, CO, NOx) contained in the exhaust gas from the engine by a catalytic reaction in the catalytic converter 16. To do. Since the catalyst has a temperature at which the catalyst starts to function, that is, a temperature at which the catalyst reacts effectively, the catalyst temperature sensor 14 detects whether or not the temperature has been reached. The high pressure side pressure sensor (high pressure transducer) 15 is attached to a high pressure pipe between the capacitor 3 and the liquid tank 4 and converts the high pressure side pressure of the refrigerant into an electric signal. The discharge pressure of the compressor 2 is replaced by this high pressure side pressure. The autoamplifier 10 determines the duty ratio as a control parameter by calculating the input signals from the switches 11 and 12 and the sensors 13, 14, 15, etc., using a built-in microcomputer. The electromagnetic valve (ECV) 9 of the compressor 2 is turned on and off to vary the capacity (inclination of the swash plate) of the compressor 2 and perform torque reduction control. Therefore, the autoamplifier 10 stores a program corresponding to the flowchart of FIG. 2 in its internal ROM, and the torque reduction control is performed by executing this program.
[0016]
Of course, the auto amplifier 10 performs normal control (hereinafter, simply referred to as “normal control”) for the air conditioner for automobiles in addition to the torque reduction control when the engine (and the air conditioner) is started. That is, although not shown, the autoamplifier 10 includes an outside air sensor that detects the outside air temperature, a solar radiation sensor that detects the amount of solar radiation, a temperature control switch for setting a desired room temperature, and the like in addition to the switches and sensors described above. Are connected to each other, and the autoamplifier 10 performs processing of signals from the sensors, the air mix PBR (built in the air mix door actuator), and the switches by a built-in microcomputer. (Intake door actuator, air mix door actuator, mode door actuator), fan control amplifier, and compressor 2 (magnet clutch 7 thereof) are operated, inlet position, outlet temperature, outlet position, outlet volume, compressor 2 ON / O of itself Also it has a function to comprehensively control the F.
[0017]
Next, the operation of the present system configured as described above will be described based on the flowchart of FIG.
First, an outline of control will be described. Here, it aims at reducing the compressor torque at the time of engine (and air-conditioner) starting. However, variable capacity control is performed until the temperature at which the catalyst functions is reached. Therefore, the temperature of the catalyst is read and the torque reduction control is performed when the temperature is equal to or lower than the set temperature. In this torque reduction control, the target discharge pressure is determined by a preset empirical formula, and the slope (discharge capacity) of the swash plate is PI (proportional integral) so that the actually detected discharge pressure matches the target discharge pressure. )Control.
[0018]
That is, as shown in the flowchart of FIG. 2, when the program starts, the autoamplifier 10 determines whether or not the control preconditions for the automotive air conditioner are satisfied in step S1. This determination is made based on, for example, data on the ON / OFF state of the ignition switch 11, the ON / OFF state of the air conditioner switch 12, and the operation permission / inhibition state of the electromagnetic valve (ECV) 9. Specifically, when the ignition switch 11 is in the ON state, the air conditioner switch 12 is in the ON state, and the solenoid valve (ECV) 9 is in the operation permitted state, it is determined that this control precondition is satisfied. Then, the following control is performed. If the control precondition is not satisfied, in step S12, the process waits while holding the value of a flag F, which will be described later, at 0, or resets the value of the flag F to 0 and ends the series of controls.
[0019]
If the control precondition is satisfied as a result of the determination in step S1, it is determined in the next step S2 whether a control execution condition for performing torque reduction control is satisfied. This determination is made based on data (catalyst temperature and vehicle interior temperature) from the catalyst temperature sensor 14 and the inside air sensor 13, for example. Specifically, the output (catalyst temperature) of the catalyst temperature sensor 14 is a preset temperature Tso (a temperature at which the catalyst starts functioning, for example, about 300 ° C. The efficiency peak is about 400 ° C. When the output of the inside air sensor 13 is equal to or lower than a predetermined set temperature Tra (for example, about 35 ° C.), it is determined that the control execution condition is satisfied, and torque reduction control is performed.
[0020]
On the other hand, if the output (catalyst temperature) of the catalyst temperature sensor 14 is equal to or higher than the set temperature Tso, or the output of the inside air sensor 13 is equal to or higher than the set temperature Tra, the value of the flag F is set to 0. While holding or resetting the value of the flag F to 0 (step S13), normal air conditioner control is performed (step S14), and the process returns to step S1.
[0021]
Here, the catalyst temperature is taken into consideration when the engine is cold at the time of starting the engine. Therefore, if the normal control is performed, the engine load increases due to the increase of the compressor torque, and the exhaust gas amount (NOx amount). Etc.) until the temperature reaches the temperature at which the catalyst begins to function (for example, about 1 minute after engine startup regardless of idling or running). This is to eliminate it. The reason why the cabin temperature is taken into consideration is that when the cabin temperature is high, it is necessary to cool the cabin rapidly, and thus cooling capacity is given priority over power saving.
[0022]
If the control execution condition is satisfied as a result of the determination in step S2, it is determined whether or not the value of the flag F is 0 in the next step S3. This flag F is for deciding whether or not to set the target discharge pressure Pd ', and is 0 in the initial state, but once the target discharge pressure Pd' is set, the target value Pd 'is set. To be maintained (no update), it is set and held at 1 until it is reset in a given case. If F = 0 in the determination of step S3, it is determined that the system is started and torque reduction control is started from now, and the process proceeds to step S4. If F = 1, the target discharge pressure has already been reached. It is determined that Pd ′ is set and torque reduction control is being executed based on the target value Pd ′, and the processing of steps S4 to S6 is omitted, and the process immediately proceeds to step S7.
[0023]
In step S4 and step S5, predetermined data is read and the target discharge pressure Pd 'is set. Specifically, the engine speed (that is, the compressor speed) Ne and the vehicle interior temperature Tr data at that time (when the system is started or before the startup) are input from the engine control device and the inside air sensor 13 (step S4). A discharge pressure target value Pd ′ necessary for reducing the compressor torque is calculated by a preset empirical formula Pd ′ = G (Ne, Tr) (step S4).
[0024]
FIG. 3 is a characteristic diagram showing an example of a target discharge pressure calculation formula. Here, for simplification of illustration, the set value of the discharge pressure target value Pd ′ with respect to the vehicle interior temperature Tr at a specific (or range) engine speed (compressor speed) Ne is shown. Has a characteristic diagram as shown in the figure for each engine speed (compressor speed) Ne (or its range). That is, the calculation formula G (Ne, Tr) for the target discharge pressure Pd ′ can be expressed in a map format using the engine speed (compressor speed) Ne and the vehicle interior temperature Tr as parameters.
[0025]
According to FIG. 3, when the vehicle interior temperature Tr before starting the system is equal to or higher than the set temperature Tra (Tr ≧ Tra) at a specific (or range) engine speed (compressor speed) Ne, As described above, normal control (maximum cooling at start-up) is performed, and when the temperature is equal to or lower than the set temperature Tra (Tr ≦ Tra), torque reduction control is performed. When performing the torque reduction control, when the vehicle interior temperature Tr is not less than the set temperature Tr1 and not more than Tra (Tr1 ≦ Tr ≦ Tra), the set value Pd1 is selected as the discharge pressure target value Pd ′ ( When Pd ′ = Pd1) and the set temperature Tr2 or more and Tr1 or less (Tr2 ≦ Tr ≦ Tr1), the set value Pd2 is selected as the discharge pressure target value Pd ′ (Pd ′ = Pd2), and the set temperature Tr2 or less. If there is (Tr ≧ Tr2), the set value Pd3 is selected as the discharge pressure target value Pd ′ (Pd ′ = Pd3). That is, here, in the torque reduction control region, as the discharge pressure target value Pd ′, three values Pd1, Pd2, and Pd3 are set stepwise according to the vehicle interior temperature Tr before the system is started. . However, Pd1> Pd2> Pd3 and Tra> Tr1> Tr2. When the vehicle interior temperature Tr is equal to or lower than the set temperature Tr2 (Tr ≧ Tr2), other compressor control, for example, low-temperature compressor protection control based on the outside air sensor detection temperature, evaporator freezing protection based on the suction temperature sensor detection temperature, is performed. Since the compressor 2 may be stopped by control or the like, torque reduction control is not always executed.
[0026]
When the target discharge pressure calculation formula Pd ′ = G (Ne, Tr) is obtained by experiment, for example, the normal vehicle interior temperature Tr is changed at various engine revolutions (compressor revolutions) Ne, and the normal control is performed. Cooling down is performed, and the change in the discharge pressure Pd with respect to time under a specific condition is examined. Since the compressor torque greatly depends on the ratio of the discharge pressure and the suction pressure (= discharge pressure / suction pressure), feedback control (here, particularly PI control) of the discharge pressure Pd is performed based on the above experimental results. In this case, a fixed target value Pd ′ is appropriately set so that the compressor torque can be reduced by a desired ratio. The target value Pd ′ set at this time is lower than the peak value of the discharge pressure in the experimental result. Therefore, by setting the target value Pd 'to a low value obtained experimentally in this way and controlling the discharge pressure Pd during operation of the air conditioner to be lower than in normal control, the compressor torque is reduced by a desired ratio. can do.
[0027]
When the target discharge pressure Pd 'is obtained in step S5, the value of the flag F is set to 1 in the next step S6. Thereby, the setting of the target discharge pressure Pd ′ again during the torque reduction control is prohibited.
[0028]
In steps S7 to S11, PI control of the discharge pressure Pd is performed using the target discharge pressure Pd 'determined in step S5.
[0029]
That is, the output of the high pressure side pressure sensor (high pressure transducer) 15, that is, the data of the current discharge pressure Pd is input (step S7), and the deviation A (= Pd'-Pd) between the target value Pd 'of the discharge pressure and the current value Pd. ) Is calculated (step S8). Thereafter, it is determined whether or not the absolute value | A | of the obtained deviation is equal to or less than a predetermined value (for example, 0.1) (step S9). If YES, since it is substantially equal to the target value Pd ′, The same control signal (duty signal having the same duty ratio) is output to the electromagnetic valve (ECV) 9 of the compressor 2. That is, the ECV control variable (duty ratio) is FO, and the previous one is FO.^*, The integrated value of A x Δh up to the previous time (where Δh is the data sampling time)^*Then,
FO = FO^*
(SO^*= 0)
It becomes. On the other hand, if the result of determination in step S9 is NO, the previous control signal is corrected so that they match, and the corrected control signal (duty signal having the corrected duty ratio) is used as the compressor 2. Output to the electromagnetic valve (ECV) 9. Specifically, the correction amount ΔF is expressed by the following equation, that is,
ΔF = Kp {A + (SO^*+ A × Δh) / T1}
Where Kp is a constant and T1 is a time constant.
This correction amount ΔF is calculated by the previous ECV control variable FO.^*To the current ECV control variable FO. That means
FO = FO^*+ ΔF
(SO^*= SO^*+ A × Δh)
It becomes.
[0030]
When a control signal (duty signal) is output to the electromagnetic valve (ECV) 9 in step S10 or step S11, the process returns to step S1 and the above processing is repeated.
[0031]
That is, when the system is started and torque reduction control is started from now, the target discharge pressure Pd 'is first set, and then the discharge pressure Pd is controlled (step S1, step S2, step S3, step S4). -Step S6-> Step S7-Step S11). Once the target discharge pressure Pd ′ is set, the discharge pressure Pd is controlled using the target discharge pressure Pd ′ as long as the control precondition and the control execution condition are satisfied (step S1 → step S2 → step S3 → step S7 to step S11 → step S1). When the control preconditions are not satisfied during the torque reduction control (for example, when the ignition switch 11 or the air conditioner switch 12 is turned off), the process is terminated (step S1 → step S12), or When the control execution condition is not satisfied (for example, when the catalyst temperature becomes equal to or higher than the set temperature), the routine shifts to normal control (step S1, step S2, step S13, step S14, step S1).
[0032]
Therefore, according to this embodiment, instead of the conventional mechanical control valve (MCV) that mechanically controls the capacity internally, an electronically operated control valve (such as an electromagnetic valve that electrically controls the capacity externally) ( ECV) 9 is used to change the capacity of the variable displacement compressor 2 to enable more detailed and complex control than before, and as such complicated control, the discharge pressure target value Pd ′ required for reducing the compressor torque Since the discharge pressure Pd is reduced by controlling the discharge pressure Pd during operation of the air conditioner to coincide with the target value Pd ', the compressor torque is reduced compared to the case where the normal control is performed. Compressor power is reduced (improves power saving performance). Moreover, since such torque reduction control is performed when the catalyst temperature is low, even if the catalyst still does not function, the engine load is reduced by reducing the compressor torque, and the amount of exhaust gas (NOx amount, etc.) is reduced. ) Is also reduced. In addition, fuel efficiency is improved by reducing compressor power.
[0033]
In this embodiment, in consideration of countermeasures for the influence of exhaust gas on the environment, the torque reduction control is performed when the air conditioner is started when the catalyst temperature is low at the time of engine start. The implementation scene of the control is not limited to this. For example, if the viewpoint of energy saving is emphasized, torque reduction control can be performed not only when the air conditioner is activated but also in cool-down control when the vehicle interior temperature is not so high. In this case, of course, it is necessary to appropriately modify the control execution condition, the target discharge pressure calculation formula, and the like in actual application.
[0034]
In the present embodiment, as a control execution condition, the torque reduction control is performed when the catalyst temperature is low and the vehicle interior temperature is equal to or lower than the set temperature in order to enable rapid cool-down at startup. Of course, it is possible to prioritize the viewpoint of energy saving even at the time of start-up and omit the condition of the vehicle interior temperature at the time of start-up.
[0035]
【The invention's effect】
As described above, according to the first aspect of the invention, the external variable control type control means is employed, and the compressor torque is reduced by controlling the discharge pressure to match the target value. This will improve fuel efficiency.
[0036]
According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, when the catalyst temperature is low and the catalyst does not function, the control is performed to reduce the compressor torque. The amount of exhaust gas from the engine (NOx amount, etc.) is reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a system configuration of a variable displacement compressor control device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the apparatus.
FIG. 3 is a characteristic diagram showing an example of a target discharge pressure calculation formula.
FIG. 4 is a general characteristic diagram of a mechanical control valve.
[Explanation of symbols]
1 ... Refrigeration cycle
2… Variable capacity compressor
9 ... Solenoid valve (control means)
10 ... Auto-amplifier (control means)
14 ... Catalyst temperature sensor (catalyst temperature detection means)
15. High pressure side pressure sensor (discharge pressure detection means)

Claims (2)

In a variable capacity compressor control device that performs variable control of a discharge capacity of a variable capacity compressor (2) constituting a refrigeration cycle (1) of an air conditioner for an automobile,
Control means (9) for controlling a control pressure for changing the discharge capacity of the variable capacity compressor (2) based on an electric signal from the outside;
A discharge pressure detecting means (15) for detecting a discharge pressure of the variable capacity compressor (2);
Engine speed recognition means for recognizing the engine speed based on a signal transmitted from the engine control device;
Vehicle interior temperature detection means (13) for detecting the temperature in the vehicle interior;
Based on the engine speed recognized by the engine speed recognition means and the vehicle interior temperature detected by the vehicle interior temperature detection means, a discharge pressure target value required for reducing compressor torque is calculated, and the discharge pressure Control means (10) for outputting an electrical signal for controlling the control means (9) so that the output of the detection means (15) matches the target value;
A variable displacement compressor control device comprising: Having catalyst temperature detection means (14) for detecting the temperature of the catalyst for purifying exhaust gas from the engine;
The variable displacement compressor control device according to claim 1, wherein the control means (10) performs the control when the output of the catalyst temperature detection means (14) is a predetermined value or less.

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