DE102006013189A1 - Compressor capacity controller for refrigerating cycle apparatus stops operation of compressor when maximum pressure exceeds second pressure control value - Google Patents

Abstract

The controller regulates a capacity control unit when the maximum pressure exceeds a first pressure control value, reducing the discharge capacity while the maximum pressure reaches the first control pressure value. The controller then stops the operation of a compressor when the maximum pressure exceeds the second control pressure value. An independent claim is also included for a refrigerating cycle apparatus.

Description

BACKGROUND THE INVENTION

Territory of invention

The The present invention relates to a capacity control system a compressor of the variable capacity type and on a refrigeration cycle system, which preferably for the use are provided in a vehicle air conditioning system.

In the past has been in refrigeration cycle systems for vehicle air conditioning the compressor designed to be driven by the vehicle engine and therefore the compressor speed could not be controlled become. Therefore, various systems have been proposed which a capacity control valve which to change the dispensing capacity the compressor is able to adjust by electrical control, so as to control the discharge capacity of the compressor by controlling the discharge capacity (See, for example, Japanese Patent Publication (A) No. 2003-129956).

The Japanese Patent Publication (A) No. 2003-129956 discloses a swash plate type compressor variable capacity, which the angle of inclination of a swash plate to change the Piston stroke changes and thereby the dispensing capacity changes, wherein through both a focus on the speed of the compressor value as well as current operating information of the compressor It is judged whether protection control of the compressor is necessary.

Further is, in a predetermined high-speed range of the compressor, when the compressor is in a high operating condition, the delivery capacity controlled by the compressor to the reduced side, while self in the predetermined high operation state of the compressor when the Compressor in a low mode is the discharge capacity of the compressor is controlled to the reduced side.

however becomes according to the Japanese Patent publication (A) No. 2003-129956 the refrigerant flow rate indirectly based on the compressor speed, the current value the capacity control value, the circle high pressure and other information is estimated the operating torque indirectly based on this refrigerant flow rate, Speed and other information, and whether the compressor is in the high state, is based on the information estimated this operating torque.

Therefore will the assessment the high-pressure state of the compressor on the basis of several Stages of estimates executed. As a result, ends the assessment the high operation state of the compressor under deviation from the actual Load condition of the compressor and therefore can control protection of the compressor (control to the side of the reduced discharge capacity) not carried out when protection control is really needed and vice versa leads protection control of the compressor to carry out the protection control if it is not required and it will kick other inconvenience.

SUMMARY THE INVENTION

One The aim of the present invention is to provide capacity control for compressor protection perform exactly.

In order to achieve this object, according to a first aspect of the present invention, there is provided a compressor capacity control system of a refrigeration cycle system for controlling a compressor. 10 ) variable capacitance, which is constructed to continuously the discharge capacity by an electrically controllable capacity control means ( 10b ), provided with
a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of the refrigeration cycle and
a tax system ( 25 ), to which a detection signal of the high-pressure side pressure-detecting means ( 22 ) and which the capacity control means ( 10b ) in accordance with the high pressure side pressure,
the control system ( 25 ) sets, as control pressure values for the high-pressure side pressure, a first control pressure value (Pd1) and a second control pressure value (Pd2) which is higher than the first control pressure value (Pd1) by a predetermined value, and
the tax system ( 25 ) the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the high-pressure side pressure exceeds the first control pressure value (Pd1), and
the compressor ( 10 ) is set in an idle state when the high-pressure side pressure exceeds the second control pressure value (Pd2).

Accordingly, the high-pressure side, wel through the high pressure side pressure sensing means ( 22 ) is used directly for controlling the compressor discharge capacity to the reduced side, so that the control of the discharge capacity for protecting the compressor against an increase in the high-pressure side pressure can be reliably performed, if necessary.

hereby is not a big one Reduction of the compressor discharge capacity before, if protection control the compressor discharge capacity is not required. Therefore, the compressor performance can be effective for the realization of the cooling capacity be used.

Even when controlling the discharge capacity of the compressor ( 10 ), when the high-pressure side pressure comes to be at a pressure exceeding the second control pressure value (Pd2), that is, when the high-pressure side pressure largely overshoots, the compressor may further 10 ) are stopped to forcibly lower the high-pressure side pressure. Accordingly, it is possible to more reliably protect the compressor against an increase in the high-pressure side pressure.

Further, under ordinary operating conditions in which the overshoot does not occur, the high-pressure side pressure can be controlled to a pressure within the second control pressure value (Pd2) by controlling the discharge capacity of the compressor (FIG. 10 ), so that the compressor ( 10 ) can be operated continuously without stopping. For this reason, the cooling operation of the refrigeration cycle system can be continuously maintained, so that the inconvenience of fluctuations in the temperature of air discharged into the cooled object or the rise of the temperature of the passenger compartment can be suppressed.

There it possible is the cooling mode of the refrigeration cycle system maintain and protection control of the compressor to this To perform way Is it possible, if a compressor with big capacity provided of the type variable capacity if this large capacity compressor is involved even in a refrigeration cycle system a small cooling capacity like him is used to continuously maintain the cooling operation and protect the compressor in the same way. Therefore can be an ordinary one Compressor used to everything from refrigeration cycle systems with big ones capacity up to refrigeration cycle systems to deal with small and medium capacity.

It should be noted that "stopping the compressor ( 10 ) in the present invention in addition to the case of completely stopping the operation of the compressor ( 10 ) the case of adjusting the discharge capacity of the compressor ( 10 ) to a minimum capacity close to 0%, to control the output of the compressor ( 10 ) into a state substantially equal to a stop.

According to a second aspect of the present invention, a compressor capacity control system of a refrigeration cycle system of the first aspect of the present invention is further provided with:
a rotation detecting means ( 24 ) for detecting an information value which is related to the speed of the compressor ( 10 ) and for inputting the detection signal into the control system ( 25 )
the control system ( 25 ) as the control pressure values for the high-pressure side pressure, the first control pressure value (Pd1) in a low-speed region below the first control speed (Nx) of the compressor (FIG. 10 ), and a third control pressure value (Pd3) in a high-speed region above the first control speed (Nx) of the compressor (FIG. 10 ),
wherein the third control pressure value (Pd3) is a pressure smaller than the first control pressure value (Pd1) and in accordance with an increase in the speed of the compressor (Pd3) 10 ) falls, and
whereby if the speed of the compressor ( 10 ) in a high-speed region above the first control speed (Nx), if the high-pressure side pressure exceeds the third control pressure value (Pd3), the capacity control means (Nx) 10b ) is controlled such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3).

Accordingly, if the speed of the compressor ( 10 ) in the low-speed region below the first control velocity (Nx), the high-pressure side pressure by the control of the discharge capacity of the compressor ( 10 ) are controlled close to the first control pressure value (Pd1).

It should be noted that the internal mechanism of the compressor ( 10 ) not only together with the increase of the pressure load, but also with the speed of the compressor ( 10 ) is substantially increased, so that if the first control pressure value (Pd1) in the low-speed region is set as it is even in the high-speed region, the internal mechanism of the compressor is ( 10 ) prone to the occurrence of an overload condition in the high-speed area.

Therefore, when the speed of the compressor ( 10 ) in the high-speed sector rich above the first control speed (Nx), a third control pressure value (Pd3) which is a pressure lower than the first control pressure value (Pd1), and together with an increase in the speed of the compressor (Nx). 10 ), and the low-pressure side pressure becomes close to the third control pressure value (Pd3) by controlling the discharge capacity of the compressor (FIG. 10 ) controlled.

Accordingly, in the high-speed region, the high-pressure side pressure to a low pressure in accordance with the increase in the speed of the compressor ( 10 ) to be controlled. As a result, protection control of the compressor, which itself accounts for an increase in the load accompanying an increase in the speed, can be performed, so that the protection of the compressor in the high-speed region can be performed more accurately.

According to a third aspect of the present invention, the compressor capacity control system of a refrigeration cycle system of the first aspect of the invention is further provided with:
a low pressure side pressure sensing means ( 23 ) for detecting the low-pressure side pressure of the refrigeration cycle and for inputting the detection signal to the control system ( 25 ), and
a speed detection means ( 24 ) for detecting an information value associated with the speed of the compressor ( 10 ) and inputting this detection signal into the control system ( 25 )
the control system ( 25 ) sets a predetermined control pressure value (Ps4) for the low-pressure side pressure, and
controls the capacity control means such that the discharge capacity is reduced and the low-pressure side pressure approaches the predetermined control pressure value (Ps4) when a speed of the compressor ( 10 ) in a high-speed region above a predetermined speed (Ny), and the low-pressure side pressure decreases from the predetermined control pressure value (Ps4).

It should be noted that if the low pressure side pressure of the circuit falls excessively, the difference between the high and the low pressures of the circuit will increase and that on the internal mechanism of the compressor ( 10 ) applied load will increase.

Therefore, in the third aspect of the present invention, when the speed of the compressor ( 10 ) in a high speed region above a predetermined control speed (Ny), if the low pressure side pressure falls from the predetermined control pressure value (Ps4), the discharge capacity is reduced and the low pressure side pressure approaches the predetermined control pressure value (PS4).

As a result of which it is possible an excessive drop the low pressure side pressure of the circuit in the high speed region to suppress, and perform the compressor protection control more accurately.

It is to be noted that the phenomenon that the low-pressure side pressure excessively falls also occurs in refrigerant leakage, but in the third aspect of the invention, in the high-speed region of the compressor (FIG. 10 ), the decision is made so that it is possible to suppress an excessive drop of the low-pressure side pressure with a normal amount of refrigerant sealed in the system by discharge capacity control.

According to a fourth aspect of the present invention, a compressor capacity control system of a refrigeration cycle system of the second aspect of the invention is further provided with
a low pressure side pressure sensing means ( 23 ) for detecting a low-pressure side pressure of the refrigeration cycle and for inputting a detection signal to the control system ( 25 )
the control system ( 25 ) sets a predetermined control pressure value (Ps4) for the low pressure side pressure, and sets a second control speed (Ny) which is exactly higher by a predetermined amount from the first control speed (Nx), and
the capacity control means ( 10b ) such that the discharge capacity is reduced and the low-pressure side pressure approaches a predetermined control pressure value (Ps4) when a speed of the compressor ( 1 ) in a high-speed region above a second control velocity (Ny), and the low-pressure side pressure decreases from the predetermined control pressure value (Ps4).

As a result From this it is possible the compressor protection control by capacity control under combination to control the first, second and third aspects of the invention.

According to a fifth aspect of the present invention, there is provided a compressor capacity control system for a refrigeration cycle system for controlling a compressor ( 10 ) of variable capacity, which is used for continuously changing the dispensing capacity by an electrically controllable capacity control means ( 10b ) is provided with
high pressure side pressure detecting means ( 22 ) for detecting a high-pressure side pressure of the Käl teerzeugungskreises,
Speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ), and
a tax system ( 25 ), which detection signals of the high-pressure side pressure detecting means ( 22 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the high-pressure side pressure and the speed of the compressor ( 10 ) controls,
the control system ( 25 ) as a control pressure value for the high-pressure side pressure, a first control pressure value (Pd1), which in a low-speed region below a predetermined control speed (Nx) of the compressor ( 10 ) is used, and a third control pressure (Pd3) which is in a high-speed region above the predetermined control speed (Nx) of the compressor ( 10 ) is used,
wherein the third control pressure value (Pd3) is designed to be a pressure lower than the first control pressure value (Pd1), and together with an increase in the speed of the compressor (Pd3) 10 ) to fall, and
the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the speed of the compressor ( 10 ) is in a low-speed range below the predetermined control speed (Nx), and the high-pressure side pressure exceeds the first control pressure value (Pd1), and
the capacity control means ( 10b ) such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3) when the speed of the compressor ( 10 ) is in a high speed range above a predetermined control speed (Nx), and the high pressure side pressure exceeds the third control pressure value (Pd3).

Accordingly, in the same manner as in the second aspect of the invention, in the high-speed region, the high-pressure side pressure to a low pressure in accordance with the increase in the speed of the compressor ( 10 ) to be controlled. Therefore, protection control of the compressor, which itself accounts for an increase in the load accompanying an increase in the speed, can be performed, so that the protection of the compressor in a high-speed region can be performed more accurately.

According to a sixth aspect of the present invention, a compressor capacity control system of a refrigeration cycle system for controlling a compressor is ( 10 ) of variable capacity, which is designed to control the dispensing capacity by an electrically controllable capacity control means ( 10b ) continuously, provided with
a low pressure side pressure sensing means ( 23 ) for detecting a low-pressure side pressure of the refrigeration cycle,
a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ), and
a tax system ( 25 ), which detection signals of the low-pressure side pressure detecting means ( 23 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the low-pressure side pressure and the speed of the compressor ( 10 ) controls,
the control system ( 25 ) sets a predetermined pressure value (Ps4) for the low-pressure side pressure, and
the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the low-pressure side pressure approaches the predetermined control pressure value (Pd4) when the speed of the compressor ( 10 ) is in a high speed range above the predetermined control speed (Ny), and the low pressure side pressure falls below the predetermined control pressure value (Pd4).

On the same way as in the third and fourth aspects of the present Invention it is possible an excessive drop low pressure side pressure in the circle in the high speed region to suppress and perform the compressor protection control more accurately.

In A seventh aspect of the invention is a compressor capacity control system a refrigeration cycle system from any one of the first to the fifth Aspects of the invention providing a rate of change of the dispensing capacity in accordance with with a difference between the high pressure side pressure and the first control pressure value (Pd1).

Accordingly, when the difference between the high pressure side pressure and the first control pressure value (Pd1) is large, the extent of change of dispensing capacity to be enlarged to cause the high pressure side pressure to be the first control pressure value (Pd1) to approach faster. Conversely, if the difference between the high pressure side Pressure and the first control pressure value (Pd1) is small, the extent of the change the dispensing capacity be lowered so that the fluctuations of the temperature of the passenger compartment blown air or the compartment temperature is reduced can be.

According to one eighth aspect of the present invention is the compressor capacity control system a refrigeration cycle system the second or fifth Aspects of the invention providing a rate of change of the dispensing capacity in accordance with with a difference between a high-pressure side pressure and a third one Control pressure value (Pd3) is set.

Accordingly, when the difference between the high pressure side pressure and the third control pressure value (Pd1) is large, the change amount of the discharge capacity is increased, to cause the high pressure side pressure to become the third one Control pressure value (Pd3) to approach faster. Conversely, if the difference between the high pressure side pressure and the third one Control pressure value (Pd3) is small, the change amount of the discharge capacity is lowered so that the fluctuations in the temperature of the passenger compartment blown air or the compartment temperature can be reduced.

According to one Ninth aspect of the present invention is the compressor capacity control system a refrigeration cycle system from any one of the first to the fifth Aspects of the invention providing the second control pressure value (Pd2) to a value which is at least 0.01 MPa greater than the first control pressure value (Pd1) is.

According to the attitude of the second control pressure value (Pd2) according to the ninth aspect of the present invention Invention can usually the high-pressure side pressure within the second control pressure value (Pd2) are controlled, and the stopping of the compressor can by Compressor capacity control be avoided.

According to a tenth aspect of the present invention, there is provided a refrigeration cycle system provided with
an evaporator ( 19 ) for absorbing heat from air to be cooled so that refrigerant evaporates,
a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant,
a capacity control means ( 10b ) connected to the compressor ( 10 ) is provided which is electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) be able to,
a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of a refrigeration cycle, and
a tax system ( 25 ), to which a detection signal of the high-pressure side pressure-detecting means ( 22 ) and which the capacity control means ( 10b ) in accordance with the high pressure side pressure,
the control system ( 25 ) sets, as control pressure values for the high-pressure side pressure, a first control pressure value (Pd1) and a second control pressure value (Pd2) which is higher than the first control pressure value (Pd1) by a predetermined value;
the control system ( 25 ) the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the high-pressure side pressure exceeds the first control pressure value (Pd1), and
the compressor ( 10 ) is set in an idle state when the high-pressure side pressure exceeds the second control pressure value (Pd2).

On this is the tenth aspect of the present invention Cooling circuit system of the first aspect of the invention and can activities and effects similar to those of the first aspect of the invention.

According to an eleventh aspect of the present invention, there is provided a refrigeration cycle system provided with
an evaporator ( 19 ) for absorbing heat from air to be cooled so that refrigerant evaporates,
a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant,
a capacity control means ( 10b ) connected to the compressor ( 10 ) is provided which is electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) be able to,
a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of a refrigeration cycle,
a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ), and
a tax system ( 25 ), which detection signals of the high-pressure side detection means ( 22 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the high-pressure side pressure and the speed of the compressor ( 10 ) controls,
the control system ( 25 ) as a control pressure value for the high-pressure side pressure, a first control pressure value (Pd1), which in a low-speed region below a predetermined control speed (Nx) of the compressor ( 10 ), and a third control pressure value (Pd3) which is in a high-speed region above the predetermined control speed (Nx) of the compressor (FIG. 10 ) is used,
wherein the third control pressure value (Pd3) is designed to be a pressure below the first control pressure value (Pd1), and along with an increase in the speed of the compressor ( 10 ) falls, and
the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the speed of the compressor ( 10 ) is in a low-speed range below the predetermined control speed (Nx), and the high-pressure side pressure exceeds the first control pressure value (Pd1), and
the capacity control means ( 10b ) such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3) when the speed of the compressor ( 10 ) is in a high-speed range above the predetermined control speed (Nx), and the high-pressure side pressure exceeds the third control pressure value (Pd3).

On this is how the eleventh aspect of the present invention covers Refrigeration cycle system of the fifth Aspect of the invention and can activities and effects similar to those of the fifth Cover aspect of the invention.

According to a twelfth aspect of the present invention, there is provided a refrigeration cycle system provided with
an evaporator ( 19 ) for absorbing air to be cooled so that refrigerant evaporates,
a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant,
a capacity control means ( 10b ) connected to the compressor ( 10 ) is provided which is electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) be able to,
a low pressure side pressure sensing means ( 23 ) for detecting a low pressure side pressure of a refrigeration cycle,
a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ),
a tax system ( 25 ), which detection signals of the low-pressure side pressure detecting means ( 23 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the low-pressure side pressure and the speed of the compressor ( 10 ) controls,
the control system ( 25 ) sets a predetermined pressure value (Ps4) for the low-pressure side pressure, and
the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the low-pressure side pressure approaches the predetermined control pressure value (Pd4) when the speed of the compressor ( 10 ) is in a high speed range above the predetermined control speed (Ny), and the low pressure side pressure falls below the predetermined control pressure value (Pd4).

On this way covers the twelfth Aspect of the present invention, a refrigeration cycle system of the sixth aspect of the invention and may be similar to activities and effects those of the sixth aspect of the invention.

It It should be noted that the reference notations in brackets after the different means the equivalent with specific agents show which in the embodiments explained below are described.

SHORT DESCRIPTION THE DRAWINGS

These and other objects and features of the present invention from the following description of preferred embodiments more clearly, which described with reference to the accompanying drawings where:

1 Fig. 12 is a view of the configuration of the entire system, showing an embodiment of the present invention;

2 FIG. 10 is a graph showing the method of determining the capacity control current value of a variable capacity compressor according to the embodiment; FIG.

3 FIG. 12 is a graph showing the relationship between a capacity control current and a low-pressure side target pressure of a variable-capacity compressor according to the embodiment; FIG.

4 FIG. 12 is a graph of control of the duty ratio of a capacity control valve of a variable capacity compressor according to the embodiment; FIG.

5 Fig. 10 is a flowchart of capacity control in the embodiment;

6 Fig. 10 is a flowchart of capacity control in the embodiment;

7 Fig. 12 is a graph explaining the operation, and shows the relationship between a refrigerant pressure and a compressor speed in the embodiment; and

8A and 8B 13 are views for explaining the behavior of the high-pressure-side pressure and low-pressure-side pressure based on a capacity control of the embodiment.

DESCRIPTION THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be explained based on the drawings. 1 shows a refrigeration cycle of a vehicle air conditioning system and its control system in accordance with the present embodiment. More particularly, the present invention relates to an air conditioning system used in a bus in which a large number of seats are arranged in the long direction of the vehicle inside the passenger compartment. A compressor 10 the refrigeration cycle has an electromagnetic clutch 10a which forms a coupling means for disengaging and engaging with the driving force. The compressor 10 is through this electromagnetic clutch 10a , a belt 11 , etc. by a vehicle engine 12 powered and sucks in a refrigerant and compresses it.

The compressor 10 is a variable capacity type compressor which is capable of continuously changing a discharge capacity by an external control signal, and is equipped with a capacity control valve 10b provided electromagnetic type.

At the delivery side of the compressor 10 are a condenser 13 , a refrigerant collector 14 , a subcooler 15 and an electric cooling fan 16 formed, which is a condensation unit 17 form. The condenser 13 Cools and condenses high-pressure gas refrigerant, which flows from the compressor 1 is discharged by the electric cooling fan 16 blown air (outside air).

The refrigerant collector 14 separates the gas and liquid phases of the refrigerant at the outlet of the condenser and supplies the liquid refrigerant to the subcooler 15 out. It stores the excess liquid refrigerant at the bottom side of a tank-shaped interior of the refrigerant collector 14 , The subcooler 15 cools the liquid refrigerant (saturated solution) from the refrigerant collector 14 through the from the electric cooling fan 16 blown air (outside air) for subcooling.

At the outlet side of the subcooler 15 is an expansion valve 18 , which forms a pressure reducing means provided. This expansion valve 18 reduces the pressure of the high pressure liquid refrigerant on the outlet side of the subcooler 15 (subcooled refrigerant) to a low-pressure gas-liquid two-phase state. The expansion valve 18 is automatically controlled in terms of the degree of opening by a known mechanism such that the overheating of the refrigerant at the outlet of the evaporator 19 is kept at a predetermined value.

The evaporator 19 is a heat exchanger for use in cooling, which is inside a housing (not shown) of a cooling unit 21 together with an electric fan 20 is arranged. The electric fan 20 sucks air inside the passenger compartment of the bus and sends it to the evaporator 19 , In the evaporator 19 The low-pressure gas-liquid two-phase refrigerant absorbs heat from the blown air and evaporates. As a result, the blown air is cooled to cool air. This cool air is supplied to cooling air ducts (not shown) disposed on the ceiling of the inside of the bus passenger compartment. The cooling air is blown from the cooling air openings of the cooling air ducts to the inside of the passenger compartment.

The refrigerant passage on the discharge side of the compressor 10 is with a high pressure side pressure sensor 22 for detecting a high-pressure-side pressure Pd provided. Further, the refrigerant passage is on the suction side of the compressor 10 with a low pressure side pressure sensor 23 for detecting a low-pressure-side pressure Ps provided. The pressure sensors 22 and 23 continuously change their electrical resistance values due to changes in the refrigerant pressure and continuously change the voltage based on this.

Inside the housing of the compressor 10 is a speed sensor 24 of the compressor 10 added. This speed sensor 24 generates a pulse-like output voltage of a frequency in accordance with the compressor speed by rotating the rotary magnetic part inside the compressor 10 at the electromagnetic coil. The detection signals of these sensors 22 . 23 and 24 be in the air conditioning control system 25 entered. At the input side of the air conditioning control system 25 are also a compartment temperature sensor 26 for detecting the compartment internal temperature Tr of the bus and other sensors and an air conditioning control panel 27 connected. The climate control console 27 is disposed in the vicinity of an instrument panel inside the compartment and allows the input of various air conditioning operation signals in the air conditioning control system 25 based on manual operation by the driver.

In particular, the air conditioning control console 27 with a temperature setting switch 27a for manually setting a desired temperature Tset in this compartment, an air volume switch 27b for manually adjusting a Luftströ mung of the electric fan 6 the cooling unit 21 ; etc. provided.

The air conditioning control system 25 includes a microcomputer and its peripheral circuits, etc. It carries out predetermined processing in accordance with a predetermined program so as to control the operation of the air conditioning devices. For this reason, on the output side of the air conditioning control system 25 the electromagnetic clutch 10a and the capacity control valve 10b of the compressor 10 , the electric cooling fan 16 the condensation unit 17 , the electric fan 20 the cooling unit 21 and other air conditioning equipment connected. These air conditioning devices are in operation by the air conditioning control system 25 controlled.

Next is a compressor 10 variable capacity explained in more detail. The compressor 10 variable capacity of the present embodiment is known as a swash plate type compressor (for example, see Japanese Patent Publication (A) No. 11-78510). By changing the control current value I which is applied to the electromagnetic capacity control valve 10b is applied, the control pressure Pc of the swash plate is changed. As a result, the change of the inclination angle of the swash plate becomes a change of the piston stroke and, in turn, the discharge capacity. Here, the discharge capacity is the geometric capacity of the working space in which the refrigerant is sucked and compressed. In particular, it is the volume of the cylinder between the top dead center and the bottom dead center of the piston stroke.

Further, in the compressor 10 of the variable capacity swash plate type, the control pressure Pc may be set to continuously change the inclination angle of the swash plate, thereby changing the discharge capacity from a 100% maximum capacity to a minimum capacity close to about 0%.

The control current value I connected to the electromagnetic capacity control valve 10b is applied by a function of the difference between the compartment internal temperature Tr (detection temperature of the compartment temperature sensor 26 ) and the set temperature Tset of the temperature setting switch 27a determines how in 2 is shown. Here, the larger the temperature difference (Tr - Tset), the greater the cooling load, so that the temperature difference (Tr - Tset) is an indicator of the cooling load (information value). The greater the temperature difference (Tr - Tset), the more the control current value I is increased.

In the capacity control valve 10b Electromagnetic type, the value of the control current I is used to change the electromagnetic force of the electromagnetic coil and adjust the valve position to control the control pressure Pc. Accurate, as in 3 is shown with increasing value of the control current I, the low-pressure-side target pressure of the refrigeration cycle (Zielsaugdruck) set lower.

Further, the valve position of the capacity control valve becomes 10b set in accordance with the target low pressure, whereby the control pressure Pc is set, and the discharge capacity changes. As a result of this change in the discharge capacity, the actual low-pressure side pressure of the refrigeration cycle is adjusted to match with the low-pressure side target pressure.

Therefore leads one Magnification of the Temperature difference (Tr - Tset) to an increase in the current value I, a drop of the low pressure side target pressure, a drop the control pressure Pc, an increase in the inclination angle of the swash plate, and an increase in the output capacity in the behavior or operation. When the temperature difference (Tr - Tset) is reduced, occurs a behavior or operation that is opposite to this and the output capacity is reduced.

The current control of the capacity control valve 10b specifically, the operation timing is controlled by the in 5 shown short waveform output. Therefore, adjustment of the control current value I means adjustment of the duty ratio. The operating time ratio is equal to t / t0. It is to be noted that it is also possible not to use this duty ratio control but to continuously change the value of the control current I (in an analogous manner) continuously.

Next, a specific example of the compressor capacity control according to this embodiment will be described with reference to FIG 5 and 6 explained. 5 and 6 show a control routine, which by the air conditioning control system 25 is processed. When the vehicle engine 12 is in operation and the air conditioning control system 25 Power is supplied, the control routine of 5 and Fig. Started. First, various operating signals, etc. of the various sensors 22 to 24 and 26 and the air conditioning control console 27 read (S10).

Next, it is decided whether or not the compressor speed Nc is greater than or equal to a first control speed Nx (S20). Here, the first control speed Nx is a speed including a high-pressure control region A and a first high-speed protection control rich B, the in 7 are delimited from each other, for example 3,000 rpm. Further, the high-pressure control area A is an area for protecting control of the compressor 10 by only the high pressure side pressure Pd. On the other hand, the first high-speed protection control area B is an area for protecting control of the compressor 10 in accordance with the high-pressure side pressure Pd and the speed Nc.

It It should be noted that in the present embodiment, the maximum speed the use of the compressor speed Nc about 6 500 rpm is, so that the first control speed Nx a speed of an extent which is a bit higher than 1/2 the maximum speed of use.

The ordinate of 7 refers to the refrigerant pressure. In the present embodiment, R134a is used as the refrigerant of the refrigeration cycle, so that in the vicinity of a refrigerant pressure of 0.3 MPa, the refrigerant temperature becomes close to 0 ° C.

If the compressor speed Nc is less than the first control speed Nx, the decision at step 20 NO and the control processing of the high pressure control logic L1 of 5 is processed. On the other hand, when the compressor speed Nc is the first control speed Nx or greater, the decision at step S20 is YES, and the control processing of the first high-speed protection control logic L2 of FIG 5 is processed.

First, in order to first explain the high pressure control logic L1, it is decided whether the high pressure side pressure Pd detected by the high pressure side pressure sensor 22 is detected, greater than or equal to the 7 shown first control pressure value Pd1 is (S30). Here, the first control pressure value Pd1 is the pressure starting the compressor protection control for reducing the pressure load on the internal mechanism of the compressor. For example, in the present embodiment, the first control pressure Pd1 is set at 2.7 MPa (see FIG 7 ).

On the other hand, the second control pressure value Pd2 is a pressure value which is exactly higher than the first control pressure value Pd1 by a predetermined value Pdd, and is a pressure of a level for immediately stopping the compressor to protect the compressor. In the first embodiment, the predetermined value Pdd is set at 0.1 Mpa while the second control pressure Pd2 is set at 2.8 MPa (see FIG 7 ). Here, the predetermined value Pdd should be set to 0.01 MPa or more for the following reasons.

According to the experiments and studies by the inventors even under ordinary Driving conditions occasionally during a compressor capacity control an overshoot of a high pressure exceeding the first control pressure value (Pd1). When the overshoot a predetermined extent or less, there is no need to use the compressor protection control to stop the Compressor to start. The extent of such overshoot, which not sufficient to start the compressor protection control differs in dependence from the application of the refrigeration cycle, so the extent of a such overshoot, which for Starting the compressor protection control is insufficient for any application can. The extent or the extent plus a safety margin may be as the above predetermined value Pdd chosen become.

From From this point of view, the predetermined value Pdd for example, 0.01 MPa or larger. Furthermore, the predetermined Value Pdd as in the present embodiment to 0.1 MPa or be chosen larger. For example, the extent of the predetermined value Pdd be selected such that the first Control pressure Pd1 plus the predetermined value Pdd in its value is not greater than the value of the high pressure becomes, which itself is to be avoided temporarily.

By doing the second control pressure value Pd2 is equal to the first control pressure value P1 plus the predetermined value Pdd in its value is it is possible to choose this one, pressures to treat in which the compressor are stopped immediately should. Further, the first control pressure value Pd1 is selected to be exactly the predetermined value Pdd lower than the second control pressure value Pd2, and to have a height of magnitude which is a realization and attitude of the considered Compressor performance allows in the range of the first control pressure value Pd1 under normal Operating conditions of the refrigeration cycle is required.

When the high-pressure side pressure Pd is smaller than the first control pressure value Pd1, as in HIGH PRESSURE (1), (2) of FIG 7 , a compressor protection control is not necessary, so that the compressor capacity is normally controlled (S40). This normal control is a control that controls the discharge capacity of the compressor 10 to adjust the low-pressure side pressure in accordance with the change of the cooling load changes.

In particular, as in the above 2 is shown, the control current value I of Capacity control valve 10b electromagnetic type by a function of the temperature difference (Tr-Tset) between the compartment internal temperature Tr and the set temperature Tset of the temperature setting switch 27a certainly. This control current value I is used to determine the low pressure side target pressure of the refrigeration cycle, as in FIG 3 is shown.

Further, the valve position of the capacity control valve becomes 10b electromagnetic type in accordance with the low pressure side target pressure (electromagnetic force of the electromagnetic coil) and the actual low pressure set. As a result, the control pressure Pc is set and the discharge capacity is changed. The discharge capacity is changed to adjust the actual low-pressure side pressure to balance with the low-pressure side target pressure.

Since the refrigerant evaporation temperature at the evaporator 19 is determined by the low pressure side pressure of the refrigeration cycle, the change in the discharge capacity for adjusting the low pressure side pressure control of the cooling performance of the evaporator 19 to a power which is appropriate to the cooling load.

On the other hand, when the high-pressure side pressure Pd is above the first control pressure value Pd1 as indicated by HIGH PRESSURE 3 of FIG 7 5, the decision at step S30 is YES, and it is decided whether the high-pressure side pressure Pd is greater than or equal to the second control pressure value Pd2 (S50). If the decision is NO, the capacity for high-pressure control is controlled on the basis of the pressure difference ΔPa in step S60.

Especially becomes the pressure difference ΔPa = first control pressure value Pd1 - actual high pressure side pressure Pd found. On the basis of this pressure difference ΔPa, the Control current setting found. This Steuerstromeinstellwert is the extent of Attitude regarding the current (pre-calculation) control current.

however the high-pressure control of S60 is executed when Pd exceeds Pd1 is, that is in the minus range of the pressure difference ΔPa, so that the extent of reduction of the control current I (extent of a Reduction of the operating time ratio) in accordance determined by the extent which is the actual high-pressure-side pressure Pd exceeds the first control pressure Pd1.

Accordingly, the bigger that Extent is to which the actual high-pressure-side pressure Pd exceeds the first control pressure Pd1 (the bigger the Pressure difference ΔPa is), the bigger it is Extent of Control current I are made, and the greater the extent of the reduction the dispensing capacity is. As a result, the high-pressure side pressure Pd can rapidly move in the direction of the first control pressure value Pd1 are lowered.

In contrast, will, if the extent, around which the actual high-pressure side pressure Pd exceeds the first control pressure value Pd1, is small, the extent of Reduction of the control current I smaller and the extent of reduction the dispensing capacity is small, so there is an advantage such that fluctuations the temperature of the air blown into the passenger compartment and In turn, the fluctuations of the compartment temperature are kept small can, and any adverse effect of the conditioning feeling is suppressed can.

It is to be noted that under normal vehicle operating conditions, the high pressure control of the above S60 makes it possible to depress the high pressure side pressure Pd to less than the second control pressure value Pd2 as indicated by the solid line in FIG 8A is shown, allowing protection control of the compressor 10 can be performed while the air conditioning system operates continuously without stop. Therefore, it is possible to control the protection of the compressor 10 to avoid concomitant inconvenience of an increase in the compartment temperature or fluctuations in the outlet temperature.

On the other hand, if an excessive response delay (overshoot) occurs in the capacity control during the execution of the high pressure control of the above S60, the high pressure side pressure Pd will occasionally rise too much and end at a pressure exceeding the second control pressure value Pd2 (see HIGH PRESSURE (3) of FIG 7 and broken line of 8A ). Such a response delay of the capacity control easily occurs when, for example, a high outside air temperature decreases the refrigerant cooling capacity of the condensation unit 17 caused and the vehicle is accelerated rapidly, the speed of the vehicle engine 12 rapidly increases and the speed of the compressor 10 also increases rapidly.

In this case, the decision at S50 becomes YES, and the operation of the refrigeration cycle is stopped at step S70. In particular, the current becomes the electromagnetic clutch 10a of the compressor 10 shut off and the compressor 10 is stopped. Simultaneously with this, the condensation unit cooling fan becomes 16 stopped. As a result of stopping of operation of the compressor 10 The overload of the internal mechanism of the compressor can be reliably eliminated and compressed sor 10 to be protected. It should be noted that the electric fan 20 the cooling unit 21 continues its operation, even if the refrigeration cycle is stopped, so that continued air is injected into the passenger compartment.

Next, the case where the decision at S20 becomes YES and the control processing of the first high-speed protection control logic L2 of FIG 5 is processed. In this control processing, it is first decided whether the high-pressure side pressure Pd is equal to or greater than a third control pressure value Pd3 (S80).

Here, the third control pressure Pd3, like the first control pressure Pd, in the high pressure control logic L1 is the pressure that starts the compressor protection control to reduce the pressure load on the internal mechanism of the compressor. However, the third control pressure value is Pd3, as in FIG 7 is determined to fall from the level of the first control pressure value Pd1 (2.7 MPa) in accordance with the increase of the compressor speed Nc, that is, to descend to the right. This is different from the first control pressure value Pd1.

The reason for determining the third control pressure Pd3 in this way will be explained next. That is, the load, which is the reliability of the compressor 10 can be substituted by the pressure difference between the high-pressure side pressure and the low-pressure side pressure and the speed. That is, the greater the difference between the high and low pressure side pressures, the greater the pressure load acting on the internal mechanism of the compressor. Further, the higher the compressor speed Nc, the more the temperature of the friction parts of the internal mechanism of the compressor increases. As a result of these reasons, the actual load of the compressor increases 10 continue on. Accordingly, the third control pressure value Pd3 is determined to decrease to the right along with an increase in the compressor speed Nc.

Further, if the actual high-pressure side pressure Pd is smaller than the third control pressure value Pd3, as by HIGH PRESSURE (1) of FIG 7 is shown, a compressor protection control is not required so that ordinary control is performed (S90). This ordinary control is equal to S40. It is a controller for adjusting the discharge capacity in accordance with the change of the cooling load.

On the other hand, when the actual high-pressure side pressure Pd exceeds the third control pressure value Pd3, as indicated by HIGH PRESSURE (2) of FIG 7 is shown, compressor control requires, so that the routine proceeds to S100, where it is decided whether the high-pressure side pressure Pd is equal to or greater than the second control pressure value Pd2. When the high-pressure side pressure Pd is smaller than the second control pressure value Pd2, the routine proceeds to S110 where the first high-speed protection control is executed.

These first high-speed protection control is a control similar to the above-mentioned high-pressure control. It finds the pressure difference ΔPb = third Control pressure Pd3 - actual high pressure side pressure Pd and controls the capacity for high pressure control based on this pressure difference ΔPb.

Especially the high-pressure control of S110 is performed in the minus range of the pressure difference ΔPd, so that the extent of Reduction of the control current I (extent of reduction of an operating time ratio) in accordance determined by the extent which is the actual high-pressure-side pressure Pd exceeds the third control pressure value Pd3.

Accordingly, the bigger that Extent is to which the actual high-pressure side pressure Pd exceeds the third control pressure value Pd3, the bigger that Extent of Reducing the control current I are made so that it is possible to increase the degree of reduction of the dispensing capacity and the high pressure side Pressure Pd toward the third control pressure value Pd1 down quickly pull.

Further will, if the extent, by which the high-pressure side pressure Pd exceeds the value, small is the extent of Reduction of the control current I also small, and it is the degree the reduction of the discharge amount small so that fluctuations in the temperature of the air blown into the passenger compartment and turn the fluctuations of the compartment temperature can be reduced.

It is to be noted that normally the high-pressure side pressure Pd may be suppressed to less than the second control pressure value Pd2, as indicated by the solid line of FIG 8A is shown by the high-pressure control of S110 is processed, and so it is possible to control the protection of the compressor 10 while the air conditioning system operates continuously without stopping.

However, if excessive response delay (overshoot) of the capacity control during the execution of the high-pressure control of S110 occurs due to a sudden increase in compressor speed or other specific factors, the high-pressure side pressure Pd will occasionally end at a pressure exceeding the second control pressure value Pd2 (see HIGH PRESSURE (3) of FIG 7 and broken lines of 8A ).

In this case, the decision of S100 becomes YES, and the refrigeration cycle is stopped at S120. In particular, the current becomes the electromagnetic clutch 10a of the compressor 10 shut off and the compressor 10 stopped. Simultaneously with this is the cooling fan 16 the condensation unit 17 stopped. As a result of stopping of operation of the compressor 10 The overload of the internal mechanism of the compressor can be reliably eliminated and it can be the compressor 10 to be protected.

Likewise, at the same time the operation of the electric fan 20 the cooling unit continued. It is to be noted that the state in which the high-pressure side pressure Pd exceeds the third control pressure Pd3, as in HIGH PRESSURE (2) of FIG 7 , easily occurs when the outside air temperature is high and the engine is operating at high speed.

Next is the in 6 illustrated second high-speed protection control logic L3 explained. The routine proceeds from S110 of 5 to S130 from 6 where it is decided whether the compressor speed Nc is equal to or greater than the second control speed Ny. Here, the second control speed Ny is the speed which is the second high-speed protection control area C which is in 7 is shown delimiting, and is a speed that is sufficiently greater than the first control speed Nx, for example 5000 U / min. This second high-speed protection control area C is the area for protective control of the compressor 10 by the low-pressure side pressure Ps and the speed Nc.

If the compressor speed Nc the second control speed Ny or bigger, will the decision at S130 YES, and then in the next S140 decided whether the actual low-pressure side Pressure Ps (detection value of the fourth control pressure Ps4) is the same or less than the fourth control pressure Ps4. Here is the fourth Control pressure Ps4, for example, 0.05 MPa. Such a low one low-pressure side pressure (negative-range pressure of Atmospheric pressure) occurs only under special conditions as during times low outside air temperature and high-speed operation, which is the maximum speed the use comes close.

When the actual low-pressure side pressure Ps is equal to or smaller than the fourth control pressure value Ps4 in the high-speed region of the second control speed Ny or above, as by LOW PRESSURE (4) of FIG 7 is shown, the routine proceeds to S150, where the second high-speed protection control is executed.

These second high-speed protection control is a control for change the control current I such that the actual low-pressure side Pressure Ps takes the fourth control pressure Ps4 or more. Especially the control current I is reduced to the minimum value of this control range. As a result, the compressor discharge capacity forcibly becomes the page the minimum capacity controlled.

By reducing the control current I and reducing the discharge capacity in this way, the actual low-pressure side pressure Ps can be raised to the fourth control pressure Ps4 or higher, as by 8B is shown.

It should be noted that the second high-speed protection control of S150 is executed again after the first high-speed protection control of S110 is executed, so that the smaller one of the control currents I determined in the two control procedures of S110 and S150 is selected to the control current I (the operating time ratio) for the capacity control valve 10b to be determined conclusively.

Accordingly, since the dispensing capacity the smaller level, based on the two control procedures of S110 and S150 can be controlled the goals of the first and second high-speed protection controls both are achieved.

If the decisions at S130 and S140 are NO, the second high-speed protection control of S150 is not executed, so that the "extent of reduction of the control current I" according to the first high-speed protection control of S110 is applied to the control current I (the operating time ratio) for the capacity control valve 10b to determine.

Other embodiments

• (1) In der vorstehenden Ausführungsform wurde das Beispiel der Reduzierung des Steuerstroms I auf den Minimumwert in dem Steuerbereich in der zweiten Hochgeschwindigkeits-Schutzsteuerung von S150 erläutert, aber es ist, wie bei der Hochdrucksteuerung von S60 und der ersten Hochgeschwindigkeits-Schutzsteuerung von S110, ebenso möglich, die Druckdifferenz als ΔPc = vierter Steuerdruckwert Ps4 – tatsächlicher niedrigdruckseitiger Druck Ps zu finden, und das Ausmaß der Reduktion des Steuerstroms I (Ausmaß der Reduktion des Betriebszeitverhältnisses) dahingehend zu bestimmen, größer zu werden, je größer die Druckdifferenz ΔPc ist, das heißt, je größer das Ausmaß, um welches der tatsächliche niedrigdruckseitige Druck Ps unterhalb des vierten Steuerdruckwerts Ps fällt, ist.
• (2) In der vorstehenden Ausführungsform wurde der Kompressor 10 variabler Kapazität mit einer elektromagnetischen Kupplung 10a versehen und der Strom zu der elektromagnetischen Kupplung 10a wurde abgeschaltet, um die elektromagnetische Kupplung 10a zur Zeit der Prozedur des Stoppens des Kälteerzeugungskreises in 5 (S70 und S120) zu entkoppeln, um so den Kompressor 10 zu stoppen, aber ein Taumelscheibentyp-Kompressor 10 variabler Kapazität ermöglicht es, den Neigungswinkel der Taumelscheibe kontinuierlich zu ändern, und die Abgabekapazität kontinuierlich von der Maximumkapazität von 100 % zu der Minimumkapazität von nahezu etwa 0 % kontinuierlich zu ändern, und so ist es ebenso möglich, die Abgabekapazität zwangsweise auf die Minimumkapazität von nahezu etwa 0 % zur Zeit des Stoppens des Kälteerzeugungskreises von 5 (S70 und S20) zu reduzieren, um so den Kompressor 10 im Wesentlichen zum Stoppen zu bringen. Hierdurch ist es möglich, die elektromagnetische Kupplung 10a des Kompressors 10 variabler Kapazität zu eliminieren, so dass der Kompressor mit kupplungslosem Aufbau hergestellt werden kann.
• (3) Die vorliegende Erfindung ist durch die Kapazitätssteuerung des Kompressors 10 variabler Kapazität gekennzeichnet und ist nicht in der Ausgestaltung des Kompressors 10 variabler Kapazität beschränkt, und kann so auch mit Kompressoren variabler Kapazität verwendet werden, die sich von dem Taumelscheibentyp unterscheiden.
• (4) In der vorstehenden Ausführungsform wurde das Beispiel eines Kompressors 10 mit variabler Kapazität, der mit einem Geschwindigkeitssensor 24 versehen ist, erläutert, aber die Geschwindigkeit des Kompressors 10 variabler Kapazität ist mit der Geschwindigkeit des Fahrzeugmotors 12 korreliert, und daher ist es auch möglich, die Geschwindigkeit des Kompressors 10 variabler Kapazität auf der Grundlage der Geschwindigkeit des Fahrzeugmotors 12 zu berechnen. Insbesondere wird der Kompressor 10 variabler Kapazität zur Rotation durch den Fahr zeugmotor 12 über eine Riemenscheibe und einen Riemen angetrieben, und daher kann die Kompressorgeschwindigkeit durch die nachfolgende Gleichung (1) berechnet werden: Kompressorgeschwindigkeit = Motorgeschwindigkeit × (motorseitiger Riemenscheibendurchmesser/kompressorseitiger Riemenscheibendurchmesser) (1)
• (5) In der vorstehenden Ausführungsform ist der niedrigere Zielwert des niedrigdruckseitigen Drucks Ps zur Zeit der Kompressorhochgeschwindigkeit, das heißt der vierte Steuerdruckwert Ps4 als fester Wert vorgesehen, und daher ist es anstelle des niedrigdruckseitigen Drucksensors 23 mit einem Sensorausgangswert, der sich kontinuierlich in Übereinstimmung mit dem Druck ändert, es auch möglich, einen Druckschalter zu verwenden, der durch den vierten Steuerdruckwert Ps4 arbeitet.
• (6) In der vorstehenden Ausführungsform ist der zweite Steuerdruckwert Pd2 ungeachtet der Kompressorgeschwindigkeit Nc als konstanter Wert vorgesehen, aber es ist auch möglich, den zweiten Steuerdruckwert Pd2 ebenso mit einer Kennlinie zu wählen, welche nach rechts zusammen mit dem dritten Steuerdruckwert Pd3 in den Hochgeschwindigkeitsbereich fällt, wo die Kompressorgeschwindigkeit Nc größer oder gleich der ersten Steuergeschwindigkeit Nx ist. Infolge hiervon ist es in dem Hochgeschwindigkeitsbereich der ersten Steuergeschwindigkeit Nx oder darüber möglich, die Zeiteinteilung des Stoppens des Kompressors zusammen mit dem Anstieg der Geschwindigkeit nach vorne zu bewegen.
• (7) In der vorstehenden Ausführungsform wurde der untere Zielwert für den niedrigdruckseitigen Druck Ps zur Zeit der Kompressorhochgeschwindigkeit, das heißt, der vierte Steuerdruckwert Ps4 als konstanter Wert vorgesehen, aber es ist ebenso möglich, diesen mit einer Kennlinie zu wählen, welche nach rechts in dem Hochgeschwindigkeitsbereich ansteigt, wo die Kompressorgeschwindigkeit Nc die zweite Steuergeschwindigkeit Ny oder größer ist. Infolge dessen ist es möglich, die Zeiteinteilung der Kapazitätssteuerung für Niedrigdrucksteuerung zusammen mit dem Ansteigen der Geschwindigkeit nach vorne zu bewegen.
• (8) In der vorstehenden Ausführungsform wurde ein Kälteerzeugungskreissystem für Fahrzeug-Klimatisierung erläutert, aber die vorliegende Erfindung kann ähnlich selbst für Kälteerzeugungskreissysteme für Anwendungen anders als die Fahrzeug-Klimatisierung verwendet werden, solange diese Kälteerzeugungskreissysteme, die mit Kompressoren 10 variabler Kapazität versehen sind.

It is to be noted that the present invention is not limited to the above embodiment and may be modified, for example, in the following ways:

• (1) In the above embodiment, the example of reducing the control current I became is explained as the minimum value in the control area in the second high-speed protection control of S150, but it is also possible, as in the high-pressure control of S60 and the first high-speed protection control of S110, the pressure difference as ΔPc = fourth control pressure Ps4 - actual low-pressure side pressure Ps, and to determine the extent of reduction of the control current I (extent of reduction of the duty ratio) to become larger, the larger the pressure difference ΔPc, that is, the larger the amount by which the actual low-pressure side pressure Ps below of the fourth control pressure Ps falls.
• (2) In the above embodiment, the compressor became 10 variable capacity with an electromagnetic clutch 10a provided and the power to the electromagnetic clutch 10a was turned off to the electromagnetic clutch 10a at the time of the procedure of stopping the refrigerating cycle in 5 (S70 and S120) to decouple the compressor 10 to stop, but a swash plate type compressor 10 variable capacity makes it possible to continuously change the inclination angle of the swash plate, and continuously change the discharge capacity continuously from the maximum capacity of 100% to the minimum capacity of almost 0%, and so it is also possible to force the discharge capacity to the minimum capacity of almost about 0% at the time of stopping the refrigeration cycle of 5 (S70 and S20) to reduce the compressor 10 essentially to stop. This makes it possible, the electromagnetic clutch 10a of the compressor 10 variable capacity, so that the compressor can be made with clutchless construction.
• (3) The present invention is by the capacity control of the compressor 10 variable capacity and is not in the design of the compressor 10 variable capacity, and so can be used with variable capacity compressors, which are different from the swash plate type.
• (4) In the above embodiment, the example of a compressor became 10 with variable capacity, with a speed sensor 24 is provided, but explains the speed of the compressor 10 variable capacity is at the speed of the vehicle engine 12 correlates, and therefore it is also possible the speed of the compressor 10 variable capacity based on the speed of the vehicle engine 12 to calculate. In particular, the compressor is 10 variable capacity for rotation by the vehicle engine 12 driven by a pulley and a belt, and therefore, the compressor speed can be calculated by the following equation (1): Compressor speed = motor speed × (motor-side pulley diameter / compressor-side pulley diameter) (1)
• (5) In the above embodiment, the lower target value of the low-pressure side pressure Ps at the time of the compressor high speed, that is, the fourth control pressure value Ps4 is provided as a fixed value, and therefore it is in place of the low-pressure-side pressure sensor 23 With a sensor output value continuously changing in accordance with the pressure, it is also possible to use a pressure switch operating by the fourth control pressure value Ps4.
• (6) In the above embodiment, the second control pressure value Pd2 is provided as a constant value regardless of the compressor speed Nc, but it is also possible to select the second control pressure value Pd2 as well having a characteristic going to the right along with the third control pressure value Pd3 in the high-speed region falls where the compressor speed Nc is greater than or equal to the first control speed Nx. As a result, in the high-speed region of the first control speed Nx or above, it is possible to advance the timing of stopping the compressor along with the rise of the speed.
• (7) In the above embodiment, the lower target value for the low-pressure side pressure Ps at the time of the high-speed compressor, that is, the fourth control pressure value Ps4, has been set as a constant value, but it is also possible to select it with a characteristic that moves to the right in FIG the high-speed region increases, where the compressor speed Nc is the second control speed Ny or greater. As a result, it is possible to advance the timing of the capacity control for low pressure control along with the increase of the speed to the front.
• (8) In the above embodiment, a refrigeration cycle system for vehicle air conditioning was explained, but the present invention can be similarly used even for refrigeration cycle systems for applications other than vehicle air conditioning, as long as these refrigeration cycle systems using compressors 10 variable capacity are provided.

While the Invention has been described with respect to specific embodiments, which were selected for purposes of illustration should be apparent be that diverse Modifications to this can be done by professionals without to depart from the basic concept and scope of the invention.

Claims (12)

Compressor capacity control system for a refrigeration cycle system for controlling a compressor ( 10 ) variable capacity, which is constructed to control the output capacity by an electrically controllable capacity control means ( 10b ), provided with a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of the refrigeration cycle, and a control system ( 25 ), to which a detection signal of the high-pressure side pressure-detecting means ( 22 ) and which the capacity control means ( 10b ) in accordance with the high pressure side pressure, the control system ( 25 ) as control pressure values for the high-pressure side pressure sets a first control pressure value (Pd1) and a second control pressure value (Pd2) higher than the first control pressure value (Pd1) by a predetermined value, and wherein the control system ( 25 ) the capacity control means ( 10b ) controls such that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the high-pressure side pressure exceeds the first control pressure value (Pd1) and the compressor ( 10 ) is set in an idle state when the high-pressure side pressure exceeds the second control pressure value (Pd2). A compressor capacity control system of a refrigeration cycle system according to claim 1, further comprising: rotation detecting means (10); 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and which is the detection signal in the control system ( 25 ), the control system ( 25 ) as the control pressure values for the high-pressure side pressure, the first control pressure value (Pd1) in a low-speed region below the first control speed (Nx) of the compressor (FIG. 10 ) and a third control pressure value (Pd3) in a high-speed region above the first control speed (Nx) of the compressor (FIG. 10 ), wherein the third control pressure value (Pd3) is a pressure lower than the first control pressure value (Pd1) and in accordance with an increase in the speed of the compressor (Pd3) 10 ), and where, when the speed of the compressor ( 10 ) in a high-speed region above the first control speed (Nx), if the high-pressure side pressure exceeds the third control pressure value (Pd3), the capacity control means (Nx) 10b ) is controlled such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3). A compressor capacity control system of a refrigeration cycle system according to claim 1, further comprising: a low pressure side pressure detecting means (FIG. 23 ) for detecting the low-pressure side pressure of the refrigeration cycle and for inputting the detection signal to the control system ( 25 ), and a speed detecting means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and inputting this detection signal into the control system ( 25 ), whereby the tax system ( 25 ) sets a predetermined control pressure value (Ps4) for the low pressure side pressure, and controls the capacity control means such that the discharge capacity is reduced and the low pressure side pressure approaches the predetermined control pressure value (Ps4) when a speed of the compressor ( 1 ) is in a high speed range above a predetermined speed (Ny) and the low pressure side pressure falls from the predetermined control pressure value (Ps4). A compressor capacity control system of a refrigeration cycle system according to claim 2, further comprising a low pressure side pressure detecting means ( 23 ) for detecting a low-pressure side pressure of the refrigeration cycle and for inputting a detection signal to the control system ( 25 ), whereby the tax system ( 25 ) sets a predetermined control pressure value (Ps4) for the low-pressure side pressure and sets a second control speed (Ny) higher than the first control speed (Nx) by exactly a predetermined amount, and the capacity control means (N4) 10b ) such that the discharge capacity is reduced and the low-pressure side pressure approaches a predetermined control pressure value (Ps4) when a speed of the compressor ( 1 ) is in a high speed range above the second control speed (Ny) and the low pressure side pressure falls from the predetermined control pressure (Ps4). Compressor capacity control system of a refrigeration cycle system for controlling a compressor ( 10 ) variable capacity, which is constructed to control the output capacity by an electrically controllable capacity control means ( 10b ) continuously, provided with a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of the refrigeration cycle, a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and a tax system ( 25 ), which detection signals of the high-pressure side pressure detecting means ( 22 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the high-pressure side pressure and the speed of the compressor ( 10 ), the control system ( 25 ) as a control pressure value for the high-pressure side pressure, a first control pressure value (Pd1), which in a low speed keitsbereich below a predetermined control speed (Nx) of the compressor ( 10 ), and a third control pressure value (Pd3) which is in a high-speed region above the predetermined control speed (Nx) of the compressor (FIG. 10 ), wherein the third control pressure value (Pd3) is designed to represent a pressure which is below the first control pressure value (Pd1) and which together with an increase in the speed of the compressor (Pd3) 10 ) and wherein the capacity control means ( 10b ) is controlled such that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the speed of the compressor ( 10 ) is in a low-speed range below the predetermined control speed (Nx), and the high-pressure side pressure exceeds a first control pressure value (Pd1), and the capacity control means ( 10b ) such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3) when the speed of the compressor ( 10 ) is in a high-speed range above the predetermined control speed (Nx), and the high-pressure side pressure exceeds the third control pressure value (Pd3). Compressor capacity control system of a refrigeration cycle system for controlling a compressor ( 10 ) variable capacity, which is constructed to control the output capacity by an electrically controllable capacity control means ( 10b ), provided with a low pressure side pressure sensing means ( 23 ) for detecting a low-pressure side pressure of the refrigeration cycle, a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and a tax system ( 25 ), which detection signals of the low-pressure side pressure detecting means ( 23 ) and the speed detection means ( 24 ) and the capacity control means ( 10b ) in accordance with the low-pressure side pressure and the speed of the compressor ( 10 ), the control system ( 25 ) sets a predetermined pressure value (Ps4) for the low-pressure side pressure, and the capacity control means (Ps4) 10b ) controls so that the discharge capacity is reduced and the low-pressure side pressure approaches the predetermined control pressure value (Pd4) when the speed of the compressor ( 10 ) is in a high speed range above the predetermined control speed (Ny), and the low pressure side pressure falls below the predetermined control pressure value (Pd4). Compressor capacity control system of a refrigeration cycle system according to any of the claims 1 to 5, which indicates a change amount of the discharge capacity in accordance with a difference between the high pressure side pressure and the first control pressure value (Pd1). An eighth aspect of the present invention is provided is the compressor capacity control system a refrigeration cycle system according to claim 2 or 5, which a change amount of the discharge capacity in accordance with a difference between the high pressure side pressure and the third control pressure value (Pd3). Compressor capacity control system of a refrigeration cycle system according to any of the claims 1 to 5, which the second control pressure value (Pd2) as a value which is at least 0.01 MPa higher than the first control pressure value (Pd1) is. Refrigeration cycle system provided with an evaporator ( 19 ) for absorbing heat from air to be cooled so that a refrigerant evaporates, a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant, a capacity control means ( 10b ) connected to the compressor ( 10 ) electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) is provided, a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of a refrigeration cycle, and a control system ( 25 ), to which a detection signal of the high-pressure side pressure-detecting means ( 22 ) and which the capacity control means ( 10b ) in accordance with the high pressure side pressure, the control system ( 25 ) as control pressure values for the high-pressure side pressure sets a first control pressure value (Pd1) and a second control pressure value (Pd2) which is higher than the first control pressure value (Pd1) by a predetermined value, and the control system ( 25 ) the capacity control means ( 10b ) controls such that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the high-pressure side pressure exceeds the first control pressure value (Pd1) and the compressor ( 10 ) is set in an idle state when the high-pressure side pressure exceeds the second control pressure value (Pd2). Refrigeration cycle system provided with an evaporator ( 19 ) for absorbing heat from air to be cooled so that a refrigerant evaporates, a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant, a capacity control means ( 10b ) connected to the compressor ( 10 ) electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) is provided, a high pressure side pressure sensing means ( 22 ) for detecting a high-pressure side pressure of a refrigeration cycle, a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and a tax system ( 25 ), which detection signals of the high-pressure side pressure detecting means ( 22 ) and the speed detection means ( 24 ) and which the capacity control means ( 10b ) in accordance with the high-pressure side pressure and the speed of the compressor ( 10 ), the control system ( 25 ) as a control pressure value for the high-pressure side pressure, a first control pressure value (Pd1), which in a low-speed region below a predetermined control speed (Nx) of the compressor ( 10 ), and sets a third control pressure value (Pd3) used in a high-speed region above the predetermined control speed (Nx) of the compressor (Nx), the third control pressure value (Pd3) being designed to represent a pressure below of the first control pressure value (Pd1) and together with an increase in the speed of the compressor ( 10 ) and the capacity control means ( 10b ) controls so that the discharge capacity is reduced and the high-pressure side pressure approaches the first control pressure value (Pd1) when the speed of the compressor ( 10 ) is in a low-speed range below the predetermined control speed (Nx), and the high-pressure side pressure exceeds the first control pressure value (Pd1), and the capacity control means ( 10b ) such that the discharge capacity is reduced and the high-pressure side pressure approaches the third control pressure value (Pd3) when the speed of the compressor ( 10 ) is in a high-speed range above the predetermined control speed (Nx), and the high-pressure side pressure exceeds the third control pressure value (Pd3). Refrigeration cycle system provided with an evaporator ( 19 ) for absorbing heat from air to be cooled so that a refrigerant evaporates, a compressor ( 10 ) for receiving and compressing by the evaporator ( 19 ) passing through refrigerant, a capacity control means ( 10b ), which in the compressor ( 10 ) electrically controllable and for continuously changing a discharge capacity of the compressor ( 10 ) is provided, a low-pressure-side pressure sensing means ( 23 ) for detecting a low-pressure side pressure of a refrigerant generation circuit, a speed detection means ( 24 ) for acquiring an information value associated with the speed of the compressor ( 10 ) and a tax system ( 25 ), which detection signals of the low-pressure side pressure detecting means ( 23 ) and the speed detection means ( 24 ) and the capacity control means ( 10b ) in accordance with the low-pressure side pressure and the speed of the compressor ( 10 ), the control system ( 25 ) sets a predetermined pressure (Ps4) for the low-pressure side pressure, and the capacity control means (Ps4) 10b ) controls so that the discharge capacity is reduced and the low-pressure side pressure approaches the predetermined control pressure value (Pd4) when the speed of the compressor ( 10 ) is in a high speed range above the predetermined control speed (Ny), and the low pressure side pressure falls below the predetermined control pressure value (Pd4).