JPH01200079A - Control for variable capacity type compressor - Google Patents

Abstract

PURPOSE:To prevent the continuous electric conduction of a driving means and suppress the heat generation by controlling the range of duty ratio within a prescribed range less than 1, in the constitution in which the discharge capacity of a compressor is controlled by controlling the operation quantity (duty ratio) of the driving means. CONSTITUTION:In an air conditioner, a condenser 3 and a receiver 4 are connected in series with the discharge pipe 2 of a variable capacity type compressor 1 in swingable swash plate constitution having a capacity varying mechanism 1a, and the receiver 4 is connected with an evaporator 6 through an expansion valve 5. The outlet pipe 6a of the evaporator 6 is connected with the suction pipe 6b of the compressor 1. The capacity varying mechanism 1a is controlled by varying the operation quantity (duty ratio) Dt of a solenoid valve 9 by a control part 8 into which the information of a sensor part 7 in the car compartment is taken. In this case, the range of the calculated duty ratio Dt is set as follows; Dt<=Dmax (Dmax<1). Therefore, the continuous electric conduction to the solenoid valve 9 is prevented, and durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control method for a variable capacity compressor, and more particularly to a novel control method for reducing heat generation of a drive means during duty ratio control.

PRIOR TECHNOLOGY Various proposals have been made as control methods for this type of variable capacity compressor, which have not been used in the past. Among them, the most representative method is the method shown in Fig. 3 ζζ. can be mentioned.

That is, in the case of the method shown in FIG. 4, after starting by turning on the air conditioner switch C (not shown), a target value for the temperature inside the vehicle is set (second step 2).

Next, the cooling load is detected according to the inside temperature of the vehicle (third step 3), and the operation amount (duty ratio: Dt) is calculated in the control section (not shown) of the air conditioner system (not shown) (fourth step 3). Step 4).

As a result of the calculation in the fourth step 4 described above, the variable capacity mechanism 1a was driven to control the discharge capacity.

However, in the conventional method described above, the duty ratio Dt is
It was controlled within the range of ≦Dt≦1.

Problems to be Solved by the Invention The conventional variable displacement compressor control method has the following problems because it is configured as described above.

First, there is a relationship as shown in FIG. 5 between the normal duty ratio Dt and the discharge capacity V of the compressor.

That is, considering the process in which the cooling load decreases, the duty JiDt gradually increases, and even after reaching Dmax, if the cooling capacity is determined to be excessive, the discharge capacity V remains constant at the minimum capacity. In spite of the,
Only the duty ratio Dt is further increased to 1.

When the duty ratio Dt is 1, the solenoid section generates a large amount of heat because it is in a continuous energization state (2), so if a solenoid valve or the like is used as the driving means, the solenoid section generates a large amount of heat. Especially for automotive compressors,
Combined with the temperature in the engine room, the solenoid valve is 200°.
In some cases, the solenoid resistance increases due to high temperatures (ζ), resulting in a decrease in magnetomotive force and problems with the durability of the solenoid valve.

In addition, in order to suppress the high temperature caused by the heat generation, there are design constraints such as enlarging the body size of the solenoid valve and using heat-radiating and heat-resistant materials.

Furthermore, in the prior art, when the duty ratio Dt is l, when the cooling load increases, the discharge capacity does not change between l→D+naX even if the duty ratio Dt is changed, so the response during this period is delayed. was.

Means for solving the above-mentioned problems have already been proposed in Japanese Patent Application No. 114889/1982, but in the present invention, we particularly pay attention to the heat generation of the drive means during duty ratio control, and reduce this heat generation. An object of the present invention is to provide a control method for a variable displacement compressor.

Means for Solving the Problems The variable displacement compressor control method according to the present invention is a variable displacement compressor in which the discharge displacement of the compressor is controlled by controlling the operation amount (duty ratio: Dt) of the drive means. In the control method for the machine, as a result of calculating the duty ratio Dt, the duty ratio range is set to Dt≦DmaxlDma.
This is a method in which x<11.

Function: In the variable capacity compressor control method according to the present invention, the duty ratio Dt is set to Dt≦Dmax, so the duty ratio remains at the maximum value and can be controlled so that the duty ratio does not exceed the maximum value. Control with quick response can be performed without wasting time.

EXAMPLE A preferred embodiment of the control method for a variable capacity compressor according to the present invention will be described below with reference to one drawing.

1 to 3 are for illustrating the control method according to the present invention. FIG. 1 is a control flow diagram showing an embodiment, and FIG. 2 is a diagram showing the relationship between the Tl control state of the solenoid valve and time. 3 are circuit diagrams showing the refrigeration circuit.

First, before describing the control method according to the present invention, a schematic configuration of a refrigeration circuit applied to the present invention will be explained.

In FIG. 3, the reference numeral 1 indicates a variable displacement compressor having a rocking swash plate configuration, for example, and the variable displacement compressor 1 includes a configuration for controlling its stroke and a configuration for controlling the effective number of cylinders. A variable capacity mechanism 1a is provided to vary the capacity of the variable capacity compressor 1 consisting of a configuration, etc., and its drive boo! Jlb is connected to and driven by an engine (not shown).

A condenser 3 and a receiver 4 are connected in series to a discharge pipe 2 of the variable capacity compressor 1, and the receiver 4 is connected to an evaporator 6 via an expansion valve 5.

The outlet pipe 6a of the evaporator 6 is connected to the variable capacity compressor 1.
It is connected to the suction pipe 6b.

Therefore, the refrigerant compressed by the variable capacity compressor 1 is condensed by the condenser 3, vaporized by the evaporator 6, and exchanges heat with the air in the vehicle interior (not shown) to perform cooling. The refrigerant vaporized and superheated in the evaporator 6 is sucked into the variable capacity compressor 1 again through the suction pipe 6b, and the above-mentioned refrigeration cycle is repeated.

The expansion valve 5 adjusts the degree of superheat of the refrigerant at the outlet 6c of the evaporator 6.

Further, the variable capacity machine IJt1a has a sensor section 7 inside the vehicle.
The operating amount of the solenoid valve 9 (
It is controlled by changing the duty ratio Dt).

Note that the specific configuration of the variable capacity mechanism 1a described above is omitted here.

Next, the operation of the embodiment of the variable displacement compressor control method according to the present invention will be described using the control flow diagram of FIG.

First, after starting by turning on the air conditioner switch (not shown) (first step 1), a target value for the temperature inside the vehicle is set (second step 2).

Next, the cooling load is detected according to the temperature inside the vehicle (third step 3), and the control unit 8 of the air conditioner system (not shown)
, the operating amount of the solenoid valve 9 (duty ratio: Dt l
(4th step 4).

As a result of the calculation in the fourth step 4 described above, if the duty ratio DC is Dt)Dmax, Dt=Dmax.
C5th step 5 of controlling the variable capacity mechanism 1a as x
), the range of duty ratio Dt is set to Dt≦Dma
It is set as x.

Here, the duty ratio Dmax is calculated from the duty ratio when it starts to rise from the minimum capacity as shown in FIG.
Furthermore, since there is a close relationship between the temperature of the solenoid valve and the amount of heat generated, Dmax is determined within a range that does not exceed a certain temperature depending on the configuration of the solenoid valve and the installation situation.

Therefore, as in this embodiment, the duty conversion Dt is set to DL≦l
)max, the control state is changed so that the minimum capacity is not 1 but Dmax as shown in FIG.
x, the shaded portion in the diagram is not energized and the amount of heat generated in the portion is reduced.

Incidentally, the present invention is not limited to the above-mentioned embodiment, and for example, the duty ratio Dmax may be changed depending on the situation of the -E magnetic valve. That is, at the time of starting, the solenoid valve has a relatively low temperature, so the duty ratio Dmnx approaches 1, and if the duty ratio Dt continues to be close to 1) yylax, the temperature becomes high. The duty ratio Dmax may be set close to the duty ratio when the capacity starts to rise from the minimum capacity shown in FIG. 4.

Furthermore, although the above embodiments have been described with reference to a car air conditioner system, the present invention can also be used as an indoor air conditioner system.

Moreover, although the case of a swinging swash plate type variable displacement compressor has been described, it goes without saying that similar effects can be obtained when the present invention is used in variable displacement compressors of other configurations.

Furthermore, it goes without saying that similar effects can be obtained if the variable capacity mechanism is controlled using other means such as duty ratio control instead of the above-mentioned solenoid valve.

Effects of the Invention Since the variable displacement compressor control method according to the present invention is configured as described above, the following effects can be obtained.

That is, the duty ratio Dt is controlled within the range of Dt≦Dmax, and the Dmax is set to be within a certain temperature due to the configuration of the driving means, etc. Therefore, continuous energization with a duty ratio of 1 The amount of heat generated is greatly reduced. This keeps the temperature of the driving means below a certain value, improving durability, making it possible to downsize the driving means without considering heat radiation or heat resistance, and improving responsiveness.

[Brief explanation of the drawing]

Figures 1 to 3 are for illustrating a method of controlling a variable displacement compressor according to the present invention. Figure 1 is a control flow diagram showing an embodiment, and Figure 2 is a relationship between the energization state of the solenoid valve and time. Fig. 3 is a circuit diagram showing the refrigeration circuit, Fig. 4 is a control flow diagram showing the conventional control method, and Fig. 5 is the discharge volume fil.
FIG. 2 is a characteristic diagram showing the relationship between v and duty ratio Dt. 1 is a variable capacity compressor, 1a is a variable capacity mechanism, 3 is a capacitor, 4 is a receiver, 5 is an expansion valve, 6 is an evaporator,
7 is a part of the sensor, 8 is a control unit, and 9 is a solenoid valve.

Claims (1)

[Claims] (1) In a variable capacity compressor control method in which the discharge capacity of the compressor is controlled by controlling the operation amount (duty ratio: Dt) of the driving means, the result of calculating the duty ratio Dt is: The range of duty ratio Dt is Dt
A method of controlling a variable capacity compressor so that ≦Dmax (Dmax<1).