Refrigeration Cycle

a technology of refrigerant and cycle, which is applied in the field of refrigerant cycle, can solve the problems of inability to estimate the flow rate of refrigerant or the torque of the compressor, the difference appears to be a relatively large error relative to the accuracy of the differential pressure to be determined, and the difference is small

Inactive Publication Date: 2012-05-24
SANDEN CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention relates to a refrigeration cycle with an orifice and pressure sensors that can accurately determine the flow rate of refrigerant and the torque of the compressor. The technical effect of the invention is to provide a refrigeration cycle that can accurately determine the differential pressure between the upstream and downstream sides of the orifice, even if there is a small difference in output characteristics between the pressure sensors. This allows for accurate estimation of the flow rate of refrigerant and the torque of the compressor, which can contribute to save fuel consumption in vehicles and other air conditioning systems for vehicles.

Problems solved by technology

However, in case where a plurality of pressure sensors are provided, there is a case where a slight difference occurs between the respective pressure sensors with regard to the output characteristics representing a relationship between a detected pressure and a sensor output ascribed to an error of manufacture of pressure sensors, etc.
Since the above-described differential pressure between the upstream and downstream sides of the orifice may become a much smaller value as compared with the absolute value of the pressure detected by each pressure sensor, if there is a slight difference in output characteristics between the respective sensors, there is a high fear that the difference appears as a relatively large error relatively to the accuracy of the differential pressure to be determined.
If a relatively large error occurs in the determined differential pressure, high-accuracy estimation of flow rate of refrigerant or torque of compressor cannot be expected.

Method used

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Examples

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Embodiment Construction

[0020]Hereinafter, desirable embodiments of the present invention will be explained referring to figures.

[0021]FIG. 1 shows a schematic structure of a refrigeration cycle according to an embodiment of the present invention. In the figure, symbol 1 indicates the whole of a refrigeration cycle, and refrigeration cycle 1 has a compressor 2 for compressing refrigerant, a condenser 3 for condensing the compressed refrigerant, an expansion valve 4 as a pressure reduction-expansion mechanism for pressure reducing and expanding the refrigerant sent from the condenser 3, and an evaporator 5 for evaporating the refrigerant sent from the expansion valve 4. In this embodiment, an orifice 7 for throttling the flow of refrigerant is provided on a refrigerant path 6 between condenser 3 and expansion valve 4 in the refrigerant circuit of refrigeration cycle 1, and at the upstream and downstream positions of the orifice 7 in the direction of the refrigerant flow, a first pressure sensor 8 and a seco...

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Abstract

Provided is a refrigeration cycle wherein, when an orifice is disposed within a refrigeration circuit, and a differential pressure between the upstream side and the downstream side of the orifice is detected using two pressure sensors, the difference between the characteristics of the pressure sensors can be adequately and easily absorbed in software, to accurately determine an actual differential pressure, so that the flow rate of refrigerant and the torque of a compressor can be accurately estimated. The refrigeration cycle wherein the orifice is provided within a refrigerant circuit, and the pressure sensors are respectively provided on the upstream side and the downstream side of the orifice, is characterized in that, with regard to output characteristics representing the relationship between the detected pressure and the sensor output of each pressure sensor, the difference between the output characteristics of one pressure sensor and the output characteristics of the other pressure sensor is determined based on the outputs of both pressure sensors at a condition where the flow of refrigerant is stopped.

Description

TECHNICAL FIELD OF THE INVENTION [0001]The present invention relates to a refrigeration cycle, and specifically, to a refrigeration cycle which has an orifice and two pressure sensors disposed on the upstream and downstream sides thereof, which enables to estimate a flow rate of refrigerant, a compressor torque, etc. more accurately and which is suitable in use for an air conditioning system for vehicles, etc.BACKGROUND ART OF THE INVENTION [0002]For example, in a refrigeration cycle having a compressor, a condenser, a pressure reduction / expansion mechanism and an evaporator in this order, for example, in a refrigeration cycle of an air conditioning system for vehicles, there is a case where pressure sensors are respectively provided at an upstream position and a downstream position in the flow direction of refrigerant in a refrigerant circuit, and a differential pressure between the pressures detected by both pressure sensors is determined. Further, in order to give a clear differe...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): F25B49/02F25B49/00
CPCF25B49/022F25B2500/19F25B2700/191F25B2341/0662F25B41/39
InventorISHIZEKI, TETSUYAINOUE, ATSUOTSUBOI, MASATOSUZUKI, KENICHI
OwnerSANDEN CORP