Air conditioning system for vehicles

a technology for air conditioning systems and vehicles, applied in the direction of instruments, heat measurement, lighting and heating apparatuses, etc., can solve the problems of unstable displacement control, decrease in compressor efficiency, etc., and achieve the effect of suppressing the drive torque of the compressor and reducing the fuel cost of the vehicl

Inactive Publication Date: 2012-12-27
SANDEN CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0017]An air conditioning system for vehicles according to the present invention makes it possible that the air conditioning system for vehicles provided with a variable displacement compressor capable of being controlled from the outside is improved in an efficiency and a vehicle fuel cost even under an operation condition where the compressor operational efficiency might decrease. Further, a vapor compression type refrigeration cycle provided with a variable displacement compressor capable of being controlled from the outside can be operated further stably, and a drive torque of the compressor can be suppressed from fluctuating.

Problems solved by technology

However in a variable displacement compressor which can be controlled from the outside, a compressor efficiency might decrease by a compressor operation with a small displacement if a displacement control signal to be input from the outside is less or equal to a certain value.
Further, because the air conditioning device is operated with a low flow rate, an expansion valve might fluctuate as causing an unstable displacement control.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0028]FIG. 2 is an example of a control flow diagram of Air conditioner 31 for vehicles in FIG. 1.

1-1.

[0029]Target value of air temperature at evaporator exit (Tet), Indoor temperature (Tin), Indoor humidity (Hin), Outdoor temperature (Tamb), Insolation (Rsun), Engine rotation speed (Ne) and Vehicle speed (VS) are detected and read in.

1-2.

[0030]A calculation means of displacement control signal for air temperature at evaporator exit calculates Displacement control signal for air temperature at evaporator exit (Ict_te), which is provisionally employed as an external variable displacement control signal. (Ict=Ict_te)

[0031]Here, the calculation means of displacement control signal for air temperature at evaporator exit consists of the following means: (Target response control means for air temperature at evaporator exit; Feedforward control input estimation means for air temperature at evaporator exit; and Feedback control input calculation means for air temperature at evaporator exit)...

example 2

[0058]FIG. 3 is another example of a control flow diagram of Air conditioner 31 for vehicles in FIG. 1.

2-1.

[0059]Target air temperature at evaporator exit (Tet), Indoor temperature (Tin), Indoor humidity (Hin), Outdoor temperature (Tamb), Insolation (Rsun), Engine rotation speed (Ne) and Vehicle speed (VS) are detected and read in.

2-2.

[0060]A calculation means of displacement control signal for air temperature at evaporator exit calculates Displacement control signal for air temperature at evaporator exit (Ict_te), which is provisionally employed as an external variable displacement control signal. (Iet=Ict_te)

2-3.

[0061]The following conditional judgment is carried out with Displacement control signal for air temperature at evaporator exit (Ict_te).

[Condition 2-1]

[0062]If the relation of Ict≦A is satisfied, the step is transited to the next external intermittent control of variable displacement.

[0063]If the relation of Ict>A is satisfied, the external intermittent control of variabl...

example 3

[0078]FIG. 4 is yet another example of a control flow diagram of Air conditioner 31 for vehicles in FIG. 1.

3-1.

[0079]Target value of evaporator exit air temperature (Tet), Indoor temperature (Tin), Indoor humidity (Hin), Outdoor temperature (Tamb), Insolation (Rsun), Engine rotation speed (Ne) and Vehicle speed (VS) are detected and read in.

3-2.

[0080]A calculation means of displacement control signal for air temperature at evaporator exit calculates Displacement control signal for air temperature at evaporator exit (Ict_te), which is provisionally employed as an external variable displacement control signal. (Ict=Ict_te)

3-3.

[0081]The following conditional judgment is carried out with Displacement control signal for air temperature at evaporator exit (Ict_te).

[Condition 3-1]

[0082]If the relation of Ict≦A is satisfied, the step is transited to the next external intermittent control of variable displacement.

[0083]If the relation of Ict>A is satisfied, the external intermittent control ...

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Abstract

Disclosed is an air conditioning system for vehicles capable of operating control with a high degree of operating efficiency even in operating states wherein efficiency would be expected to decline, and while adhering to conventional control ideas. The air conditioning system for vehicles comprises a compressor that compresses a refrigerant; a condenser that condenses the compressed refrigerant; an expansion mechanism that expands the condensed refrigerant; an evaporator that evaporates the expanded refrigerant and brings the evaporated refrigerant into contact with air, cooling and dehumidifying the air; a blower that sends the air to the condenser; and a displacement control signal calculation means for determining a displacement control signal, using a displacement control signal calculation formula, which is to be inputted to the compressor from the outside. In the displacement control signal calculation means, a target air temperature at the evaporator exit is inputted, the displacement control signal is determined using the difference between the air temperature and the target air temperature at the evaporator exit when a displacement control signal calculated value is less than or equal to a predetermined value (A), and the displacement control signal is determined from the displacement control signal calculation formula when the displacement control signal calculated value is greater than the predetermined value (A).

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to a technology for controlling a displacement of a variable displacement compressor in an air conditioning system provided with a vapor compression type refrigeration cycle for vehicles, wherein a displacement control signal which is input from the outside to the variable displacement compressor is calculated as based on a target temperature of an air conditioning in an evaporator and is output.BACKGROUND ART OF THE INVENTION[0002]Patent document 1 discloses a control device which is applicable to an automatic air conditioning system for vehicles. This control device has a target response calculation means for a controlled output, which calculates the target response of the controlled output to be designated so as to reach a target value in a transient state. Further, the control device has a feedforward control input estimation means for the target response of the controlled output and also has a controlled output...

Claims

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Application Information

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IPC IPC(8): F25B49/02
CPCB60H1/3211B60H2001/3275B60H2001/3261
InventorSUZUKI, KENICHI
OwnerSANDEN CORP