Control plunger sleeve structure

Abstract

The invention provides a control plunger sleeve structure. The control plunger sleeve structure comprises a control plunger sleeve, a control plunger spring, a control plunger body and a control plunger cavity. The control plunger sleeve is connected with the pore plate, the control plunger body is sleeved with the control plunger sleeve, so that a control plunger cavity is formed between the control plunger body and the control plunger sleeve, an oil inlet and return hole is formed in the pore plate, and the oil inlet and return hole is communicated with the control plunger cavity; and a control plunger spring is arranged between the control plunger sleeve and the control plunger. The opening response speed of the needle valve can be increased.

Description

Technical Field

[0001] The invention belongs to the field of common rail fuel injectors, and in particular relates to a control plunger sleeve structure. Background Art

[0002] During the injection process of the common rail injector, an important evaluation index is the injection law. The requirements for the injection law vary slightly according to the specific actual situation, but in general, it increases slowly in the front section and decreases rapidly in the back section. In order to meet the emission regulations of the engine and improve the economy and controllability, the requirements for the flexibility of the injection characteristics of the fuel injection system are getting higher and higher. The purpose is to achieve efficient combustion and clean emissions at all operating points of the engine. The matching fuel system is required to be able to inject fuel into the engine cylinder in a timely and quantitative manner according to the established injection law, and mix well with the compressed air in the cylinder after being fully atomized. The matching of the injection law and the ventilation process is the main research approach to improve combustion performance;

[0003] At present, the electronically controlled common rail injector has developed to the fourth generation, and the injection pressure has been increased from the initial 160MPa to more than 220MPa. However, the key component of the injector, the control plunger sleeve, has been used to this day without any improvement, which affects the closing speed of the needle valve. Summary of the invention

[0004] In view of this, the present invention aims to propose a control plunger sleeve structure to improve the opening response speed of the needle valve.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A control plunger sleeve structure, comprising a control plunger sleeve, a control plunger spring, a control plunger body and a control plunger cavity;

[0007] The control plunger sleeve is connected to the orifice plate, and the control plunger body is sleeved into the control plunger sleeve, so that a control plunger cavity is formed between the control plunger body and the control plunger sleeve.

[0008] The orifice plate is provided with an oil inlet and return hole, and the oil inlet and return hole is communicated with the control plunger cavity;

[0009] A control plunger spring is arranged between the control plunger sleeve and the control plunger.

[0010] Furthermore, the inner surface of the connection between the control plunger sleeve and the orifice plate is provided with a chamfer, and the angle of the chamfer is 30°-45°.

[0011] Compared with the prior art, the control plunger sleeve structure described in the present invention has the following advantages:

[0012] The present invention provides a control plunger sleeve structure. The improved control plunger sleeve has a chamfered corner. In addition to the expansion force, the upper side also increases a downward liquid force. The spring under the control plunger sleeve is compressed, and the control plunger sleeve moves downward accordingly. The high-pressure fuel discharge speed becomes faster, and the needle valve responds promptly, thereby improving the opening response speed of the needle valve. At the same time, since the upper surface of the control plunger sleeve has a chamfered corner, the sealing surface becomes narrower and the sealing pressure increases, thereby achieving a better high-pressure sealing effect.

[0013] The liquid pressure exerted on the control plunger cavity formed on the upper side of the control plunger sleeve before the improvement is the expansion force. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 This is a schematic diagram of the structure of the control plunger sleeve according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the control plunger sleeve structure before improvement according to an embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram of a one-dimensional simulation model of two control plunger sleeve structures according to an embodiment of the present invention;

[0018] Figure 4 A schematic diagram of the closing speed of a needle valve of a plunger sleeve structure without chamfers according to an embodiment of the present invention;

[0019] Figure 5 A schematic diagram of the closing speed of a needle valve with a chamfered plunger sleeve structure according to an embodiment of the present invention;

[0020] Figure 6 A schematic diagram of increasing oil volume fluctuation in the plunger sleeve structure without chamfers according to an embodiment of the present invention;

[0021] Figure 7 Schematic diagram of increasing oil volume fluctuations in the chamfered plunger sleeve structure according to an embodiment of the present invention.

[0022] Description of reference numerals:

[0023] 1. Control plunger sleeve; 2. Control plunger spring; 3. Control plunger body; 4. Control plunger cavity; 5. Oil inlet and return holes; 6. Orifice plate; 7. Chamfer DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0027] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0028] A control plunger sleeve structure, comprising a control plunger sleeve, a control plunger spring, a control plunger body and a control plunger cavity;

[0029] The control plunger sleeve is connected to the orifice plate, and the control plunger body is sleeved into the control plunger sleeve, so that a control plunger cavity is formed between the control plunger body and the control plunger sleeve.

[0030] The orifice plate is provided with an oil inlet and return hole, and the oil inlet and return hole is communicated with the control plunger cavity;

[0031] A control plunger spring is arranged between the control plunger sleeve and the control plunger.

[0032] Preferably, the inner surface of the connection between the control plunger sleeve and the orifice plate is provided with a chamfer, and the angle of the chamfer is 30°-45°.

[0033] like Figure 3-Figure 7 As shown:

[0034] Figure 4 Without chamfer, it can be seen that the pressure in the control chamber gradually increases, and the closing speed of the needle valve slows down.

[0035] Figure 5 There is a chamfer, which shows that the pressure in the control chamber is balanced and the closing speed of the needle valve is stable;

[0036] Figure 6 There is no chamfer, and the oil volume fluctuation increases with the increase of injection times;

[0037] Figure 7 There is a chamfer, and the oil volume fluctuation is stable as the number of injections increases.

[0038] The hydraulic pressure on the control plunger cavity formed on the upper side of the control plunger sleeve before the improvement is an expansion force. The improved control plunger sleeve has a chamfer, and in addition to the expansion force, a downward hydraulic pressure is added on the upper side. The spring under the control plunger sleeve is compressed, and the control plunger sleeve moves downward, the high-pressure fuel is discharged faster, and the needle valve responds promptly, thereby improving the opening response speed of the needle valve. At the same time, due to the chamfer added to the upper surface of the control plunger sleeve, the sealing surface becomes narrower and the sealing pressure increases, thereby achieving a better high-pressure sealing effect.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control plunger sleeve structure, characterized in that: It includes a control plunger sleeve, a control plunger spring, a control plunger body and a control plunger cavity; The control plunger sleeve is connected to the orifice plate, and the control plunger body is sleeved into the control plunger sleeve, so that a control plunger cavity is formed between the control plunger body and the control plunger sleeve. The orifice plate is provided with an oil inlet and return hole, and the oil inlet and return hole is communicated with the control plunger cavity; A control plunger spring is arranged between the control plunger sleeve and the control plunger.

2. A control plunger sleeve structure according to claim 1, characterized in that: The inner surface of the connection between the control plunger sleeve and the orifice plate is provided with a chamfer, and the angle of the chamfer is 30°-45°.

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