US-12624869-B2 - Heat pump cycle device

US12624869B2US 12624869 B2US12624869 B2US 12624869B2US-12624869-B2

Abstract

A heat pump cycle device includes a compressor, a branching unit, a heating unit, a heating-unit-side depressurizing unit, a bypass passage, a bypass flow-rate adjusting unit, a mixing unit, and a target pressure difference determining unit. The target pressure difference determining unit determines a target pressure difference as a target value of a pressure difference determined by subtracting a suctioned refrigerant pressure from a discharge refrigerant pressure. An operation of at least one of the compressor, the heating-unit-side depressurizing unit, or the bypass flow-rate adjusting unit is controlled so that the pressure difference comes close to the target pressure difference.

Inventors

Kota Takeichi
Atsushi Inaba
Yuichi Kami
Kengo Sugimura
Daiki Kato

Assignees

DENSO CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240312
Priority Date: 20210924

Claims (6)

1 . A heat pump cycle device comprising: a compressor configured to compress a refrigerant and discharge the refrigerant; a first joint configured to branch a flow of the refrigerant discharged from the compressor; a condenser configured to heat a heating target with a heating source that is one of the refrigerants branched by the first joint; a first valve configured to depressurize the refrigerant which has flowed out from the condenser; a bypass passage configured to allow another of the refrigerants branched by the first joint to flow toward a suction port side of the compressor through the bypass passage; a second valve configured to adjust a flow rate of the refrigerant passing through the bypass passage; a second joint configured to allow the refrigerant which has flowed out from the second valve and the refrigerant which has flowed out from the first valve to mix with each other and flow toward the suction port side of the compressor; and a processor with a memory storing computer program code executable by the processor, the processor configured to determine a target pressure difference that is a target value of a pressure difference determined by subtracting a suctioned refrigerant pressure of the refrigerant drawn into the compressor from a discharge refrigerant pressure of the refrigerant discharged from the compressor, wherein an operation of at least one of the compressor, the first valve, or the second valve is controlled so that the pressure difference approaches the target pressure difference, and an operation of at least another one of the compressor, the first valve, or the second valve, which is not used for controlling the pressure difference, is controlled so that the suctioned refrigerant pressure approaches a target suctioned refrigerant pressure, in an operation mode in which the refrigerant which has flowed out from the second valve and the refrigerant which has flowed out from the first valve are directly mixed with each other.
2 . The heat pump cycle device according to claim 1 , wherein the processor is configured to: control an operation of the second valve; and control the operation of the second valve so that the pressure difference approaches the target pressure difference.
3 . The heat pump cycle device according to claim 2 , wherein the processor is configured to estimate a throttle passage area of the second valve based on the target pressure difference and control the operation of the second valve by feed-forward control.
4 . The heat pump cycle device according to claim 1 , wherein the processor is configured to: control a refrigerant discharge capability of the compressor; and control the operation of the compressor so that the suctioned refrigerant pressure approaches the target suctioned refrigerant pressure.
5 . A heat pump cycle device comprising: a compressor configured to compress a refrigerant and discharge the refrigerant; a first joint configured to branch a flow of the refrigerant discharged from the compressor; a condenser configured to heat a heating target with a heating source that is one of the refrigerants branched by the first joint; a first valve configured to depressurize the refrigerant which has flowed out from the condenser; a bypass passage configured to allow another of the refrigerants branched by the first joint to flow toward a suction port side of the compressor through the bypass passage; a second valve configured to adjust a flow rate of the refrigerant passing through the bypass passage; a second joint configured to allow the refrigerant which has flowed out from the second valve and the refrigerant which has flowed out from the first valve to mix with each other and flow toward the suction port side of the compressor; a processor with a memory storing computer program code executable by the processor, the processor configured to: determine a target pressure difference that is a target value of a pressure difference determined by subtracting a suctioned refrigerant pressure of the refrigerant drawn into the compressor from a discharge refrigerant pressure of the refrigerant discharged from the compressor; control an operation of the second valve; control the operation of the second valve so that the pressure difference approaches the target pressure difference; and estimate a throttle passage area of the second valve based on the target pressure difference and control the operation of the second valve by feed-forward control.
6 . The heat pump cycle device according to claim 1 , wherein the processor is configured to: determine a target temperature of the heating target; and determine the target pressure difference so as to increase as the target temperature rises.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation application of International Patent Application No. PCT/JP2022/033871 filed on Sep. 9, 2022, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2021-155295 filed on Sep. 24, 2021. TECHNICAL FIELD The present disclosure relates to a heat pump cycle device for heating a heating target by using heat generated by a work of a compressor. BACKGROUND Conventionally, a heat pump cycle device is applied to an air conditioner for a vehicle. In the heat pump cycle device, in a heating mode of heating the inside of a vehicle compartment, a refrigerant circuit may be switched to a hot-gas heater circuit. SUMMARY A heat pump cycle device according to at least one embodiment of the present disclosure includes a compressor and a target pressure difference determining unit. The compressor is configured to compress a refrigerant and discharge the refrigerant. The target pressure difference determining unit is configured to determine a target pressure difference that is a target value of a pressure difference determined by subtracting a suctioned refrigerant pressure of the refrigerant drawn into the compressor from a discharge refrigerant pressure of the refrigerant discharged from the compressor. An operation of the compressor may be controlled so that the pressure difference comes close to the target pressure difference. BRIEF DESCRIPTION OF DRAWINGS The above object, other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the appended drawings. FIG. 1 is a schematic general configuration diagram of an air conditioner for a vehicle of a first embodiment. FIG. 2 is a schematic configuration diagram of an inside air-conditioning unit of a first embodiment. FIG. 3 is a block diagram illustrating an electric control unit of the air conditioner for a vehicle of the first embodiment. FIG. 4 is a flowchart of a main routine of a control program of the first embodiment. FIG. 5 is a flowchart of a subroutine of a control program of the first embodiment. FIG. 6 is a schematic general configuration diagram illustrating the flow of a refrigerant in a hot gas heating mode of a heat pump cycle of the first embodiment. FIG. 7 is a Mollier diagram illustrating changes in the state of the refrigerant in the hot gas heating mode of the heat pump cycle of the first embodiment. FIG. 8 is a schematic general configuration diagram illustrating the flow of a refrigerant in a hot gas dehumidifying-heating mode of a heat pump cycle of the first embodiment. FIG. 9 is a Mollier diagram illustrating changes in the state of the refrigerant in the hot gas dehumidifying-heating mode of the heat pump cycle of the first embodiment. FIG. 10 is a schematic general configuration diagram illustrating the flow of a refrigerant in a heating-only mode of a heat pump cycle of the first embodiment. FIG. 11 is a Mollier diagram illustrating changes in the state of the refrigerant in the warming-up-only mode of the heat pump cycle of the first embodiment. FIG. 12 is a schematic general configuration diagram illustrating the flow of a refrigerant in a defrosting mode of a heat pump cycle of the first embodiment. FIG. 13 is a Mollier diagram illustrating changes in the state of the refrigerant in the defrosting mode of the heat pump cycle of the first embodiment. FIG. 14 is a schematic general configuration diagram of an air conditioner of a second embodiment. FIG. 15 is a schematic general configuration diagram of an air conditioner of a third embodiment. DETAILED DESCRIPTION To begin with, examples of relevant techniques will be described. A heat pump cycle device according to a comparative example is applied to an air conditioner for a vehicle. In the heat pump cycle device, in a heating mode of heating the inside of a vehicle compartment, a refrigerant circuit is switched to a hot-gas heater circuit. In the hot-gas heater circuit, refrigerant discharged from a compressor is circulated through a fixed throttle, an inside heat exchanger, and the suction port side of the compressor in this order. In the heat pump cycle device of the comparative example, in the heating mode, blown air that is blown into the vehicle compartment is heated via heat exchange in the inside heat exchanger between the refrigerant depressurized by the fixed throttle and the blown air. Therefore, in the heat pump cycle device, in the heating mode, the blown air that is a heating target is heated with heat generated by a work of a compressor without using heat absorbed from the outside air and the like. Further, in the heat pump cycle device of the comparative example, in the heating mode, a discharge refrigerant pressure that is a pressure of the refrigerant discharged from the compressor is controlled so as to come close to a target high pressure. However, in the heat pump