System and method for controlling an expansion valve

Patent metadata

Field	Value
Publication number	US-11313601-B2
Application number	US-201816642881-A
Country	US
Kind code	B2
Filing date	Aug 8, 2018
Priority date	Aug 29, 2017
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A control method and a control system are provided. A valve closing position of a valve device can be controlled according to the current flow direction or working mode of a refrigerant. A stroke of the valve device from a fully-opened position to a fully-closed position is defined as a total valve closing stroke. When the flow direction of the refrigerant is a forward direction, the valve device is controlled to operate at a first valve closing position, and when the flow direction of the refrigerant is a reverse direction, the valve device is controlled to operate at a second valve closing position. The first valve closing position is different from the second valve closing position, such that wear caused by valve closing can be reduced.

First claim

The invention claimed is:

1. A method for controlling a valve device to operate at a valve closing position, comprising:
determining a first valve closing position as the valve closing position in a case that a direction of a system pressure applied on a valve needle of the valve device is identical to a valve closing direction; and
determining a second valve closing position as the valve closing position in a case that the direction of the system pressure applied on the valve needle of the valve device is different from the valve closing direction, wherein
the valve closing position comprises at least the first valve closing position and the second valve closing position, the first valve closing position is different from the second valve closing position, and the first valve closing position is set farther from a fully-closing position than the second valve closing position, and
a total valve closing stroke is a stroke of the valve device from a fully-opening position to the fully-closing position.

2. The method according to claim 1 , further comprising:
acquiring a current flow direction of a working medium or a pressure difference across a system inlet-outlet;
determining, based on the current flow direction of the working medium or the pressure difference across the system inlet-outlet, whether the direction of the system pressure applied on the valve needle of the valve device is identical to the valve closing direction, to determine the first valve closing position or the second valve closing position as the valve closing position of the valve device; and
controlling the valve device to operate at the first valve closing position or the second valve closing position.

3. The method according to claim 1 , wherein in a case that a current flow direction of a working medium is forward or a pressure difference across a system inlet-outlet is positive, the direction of the system pressure applied on the valve needle of the valve device is identical to the valve closing direction, and
the method further comprises: controlling the valve device to operate at the first valve closing position, wherein the valve device is an electronic expansion valve and a stroke from the first valve closing position to the fully-opening position is of 90% to 99% of the total valve closing stroke.

4. The method according to claim 3 , wherein in a case that the current flow direction of the working medium is backward or the pressure difference across the system inlet-outlet is negative, the method further comprises:
controlling the valve device to operate at the second valve closing position, wherein the second valve closing position is identical to the fully-closing position.

5. The method according to claim 4 , further comprising:
acquiring a target flow rate;
determining a valve-opening starting position and a valve-opening ending position of the valve device based on the current flow direction of the working medium and the target flow rate, or determining the valve-opening starting position and the valve-opening ending position of the valve device based on the pressure difference across the system inlet-outlet and the target flow rate; and
controlling the valve device to operate from the valve-opening starting position to the valve-opening ending position, wherein
the fully-opening position of the valve device is a position at which a flow rate of the valve device is maximum, the fully-closing position of the valve device is a fully-closing mechanically-limiting position of the valve device, a target position corresponding to the target flow rate is a position at which the flow rate reaches the target flow rate.

6. The method according to claim 5 , wherein
in a case that the current flow direction of the working medium is forward or the pressure difference across the system inlet-outlet is positive, the valve-opening starting position is identical to the first valve closing position; and
in a case that the current flow direction of the working medium is backward or the pressure difference across the system inlet-outlet is negative, the valve-opening starting position is identical to the second valve closing position, and wherein
the valve-opening ending position is identical to the target position corresponding to the target flow rate.

7. The method according to claim 1 , wherein the valve device is an electronic expansion valve, and the electronic expansion valve comprises:
a motor comprising a coil and a rotor;
a valve body; and
a valve assembly comprising a transmission element, a buffer spring and the valve needle, and wherein
the electronic expansion valve is provided with a valve port, rotation of the rotor is converted into up-and-down motion of the valve needle via the transmission element, and
the buffer spring is arranged between the transmission element and the valve needle, and a large elasticity coefficient of the buffer spring corresponds to a large range of an allowable stroke from the first valve closing position to the fully-opening position.

8. The method according to claim 7 , wherein the electronic expansion valve further comprises: a control unit configured to control the valve needle to operate at the first valve closing position or the second valve closing position.

9. The method according to claim 1 , wherein a refrigerating system has at least two different operation modes, and a working medium of the refrigerating system flows through the valve device in different directions in the two different operation modes, and wherein
the method further comprises:
acquiring an operation mode of the refrigerating system;
determining, based on the operation mode, whether the direction of the system pressure applied on the valve needle of the valve device is identical to the valve closing direction, to determine the first valve closing position or the second valve closing position as the valve closing position of the valve device; and
controlling the valve device to operate at the first valve closing position or the second valve closing position.

10. The method according to claim 9 , wherein the refrigerating system has a refrigerating mode and a heating mode, and a flow direction of the working medium in the refrigerating mode is opposite to the flow direction of the working medium in the heating mode, and wherein
in a case that the flow direction of the working medium is forward in the refrigerating mode or a pressure difference across the system inlet-outlet is positive in the refrigerating mode, the first valve closing position is determined as the valve closing position in the refrigerating mode; and in a case that the flow direction of the working medium is backward in the heating mode or the pressure difference across the system inlet-outlet is negative in the heating mode, the second valve closing position is determined as the valve closing position in the heating mode;
in a case that the flow direction of the working medium is backward in the refrigerating mode or the pressure difference across the system inlet-outlet is negative in the refrigerating mode, the second valve closing position is determined as the valve closing position in the refrigerating mode; and in a case that the flow direction of the working medium is forward in the heating mode or the pressure difference across the system inlet-outlet is positive in the heating mode, the first valve closing position is determined as the valve closing position in the heating mode; and
the valve device is controlled to operate at the first valve closing position or the second valve closing position based on the operation mode, wherein a stroke from the first valve closing position to the fully-opening position is of 90% to 99% of th

Assignees

• Hangzhou Sanhua Res Inst Co Ltd

Inventors

• Zhang Bin
• Xie Jinlan

Classifications

• Y02B30/70

  Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating · CPC title

• F25B41/35

  by rotary motors, e.g. by stepping motors · CPC title

• F25B2341/06

  Details of flow restrictors or expansion valves · CPC title

• F25B41/38

  specially adapted for reversible cycles, e.g. bidirectional expansion restrictors · CPC title

• F25B2600/2513

  Expansion valves · CPC title