CN201513270U - Common rail system restrictor valve assembly - Google Patents

Abstract

The utility model discloses a flow limiting valve assembly of a common rail system. The flow limiting valve assembly of the common rail system comprises a common rail pipe and a flow limiting valve assembly, wherein internal threads are formed on the inner wall of one end of a flow limiting valve body of the flow limiting valve assembly connected with the common rail pipe; external threads are formed on one end of the common rail pipe connected with the flow limiting valve body; the internal threads fit the outer threads; and a sealing base is arranged at the joint of the flow limiting valve body and the common rail pipe. The flow limiting valve assembly can lower the pressure fluctuation in the common rail pipe so as to supply fuel to a fuel injector at the stable pressure, and can cut off the fuel passage when excessive fuel is supplied, thereby preventing abnormal fuel supply. The flow limiting valve assembly has the advantages of simple detachment and easy maintenance.

Description

Common rail system restrictor valve assembly

technical field

The utility model relates to an engine oil supply technology, in particular to a flow limiting valve assembly of a common rail system.

technical background

With the country's increasing emphasis on environmental protection, more stringent emission regulations will be implemented. Diesel engines with IV and V emissions in Daguo have become the research direction of domestic engine factories, and the fuel supply system is one of the most important components affecting engine emissions, and it is bound to develop towards the world's most advanced common rail system.

The common rail technology forms constant high-pressure fuel directly or indirectly through the common rail, distributes it to each injector, and quantitatively controls the amount of fuel injected into the combustion chamber by the injector by means of the opening and closing of the restrictor valve. So as to ensure that the diesel engine achieves the best atomization, combustion and the least pollution emission. As a kind of common rail, it is of great significance to reduce the pressure pulsation in the common rail pipe and provide the fuel common rail system restrictor valve to the injector with a stable pressure.

Utility model content

The invention provides a flow limiting valve assembly of a common rail system, which includes a common rail pipe and a flow limiting valve assembly. There is an internal thread, and an external thread is provided on the connecting end of the common rail pipe and the flow limiting valve body, and the internal thread and the external thread match each other, and a sealing seat is provided at the interface between the flow limiting valve body and the common rail pipe. Its specific structure is:

The restrictor valve assembly includes: sealing seat, restrictor valve, restrictor valve body, restrictor valve spring;

The inner hole of the flow limiting valve is divided into three sections according to the diameter, and the diameters of the inner holes of the three sections increase sequentially from top to bottom, forming the first diameter inner hole, the second diameter inner hole, and the third diameter inner hole;

The restrictor valve is arranged in the inner hole of the second diameter, and the restrictor valve spring is arranged between the bottom of the inner hole of the second diameter and the restrictor valve, and the restrictor valve spring is in a pre-compressed state,

There is a sealing cone surface at the junction of the inner hole of the first diameter and the inner hole of the second diameter, and the sealing cone surface matches the upper end of the flow limiting valve; the lower end of the flow limiting valve has an axial groove, and the upper part of the flow limiting valve has a radial through hole. The through hole communicates with the axial groove at the lower end of the restrictor valve and the inner hole of the second diameter;

The sealing seat is arranged in the inner hole of the third diameter, the upper end of the sealing seat is attached to the bottom of the inner hole of the third diameter, and the lower end of the sealing seat is a tapered surface;

The opening end of the inner hole at the connection between the common rail pipe and the restrictor valve body is a trumpet-shaped opening, and the tapered surface at the lower end of the sealing seat matches the trumpet-shaped opening on the restrictor valve body;

A through hole is arranged in the axial center of the seal seat, and the axial through hole of the seal seat communicates with the inner hole of the common rail pipe and the inner hole of the second diameter.

The beneficial technical effects of the present invention are: on the one hand, the flow limiting valve of the common rail system can reduce the pressure pulsation in the common rail pipe, and provide fuel to the injector with a stable pressure, and at the same time, it can also cut off the fuel passage when the fuel is oversupplied , so as to prevent abnormal supply of fuel, and at the same time have the characteristics of simple disassembly and easy maintenance.

Description of drawings

Figure 1. The passage state of the flow limiting valve of the common rail system;

Figure 2. The closed state of the flow limiting valve of the common rail system;

Common rail pipe 1, sealing seat 2, flow limiting valve 3, flow limiting valve body 4, flow limiting valve spring 5.

Detailed ways

The working principle of the flow limiting valve of the common rail system is: when the common rail pipe works normally, the fuel flowing out from the common rail pipe 1 passes through the holes of the sealing seat 2, the flow limiting valve 3 and the flow limiting valve body 4 (in the figure The arrow indicates that the fuel flow direction) is supplied to the injector; when pressure fluctuations occur in the high-pressure pipe, the resistance generated by it through the restrictor valve hole of the common rail system destroys the pressure balance between the common rail pipe and the injector, so the common rail system The restrictor valve will move to the upper part of the restrictor valve body to absorb pressure fluctuations; under normal pressure fluctuations, the injection will stop due to the decrease of fuel flow; as the amount of fuel passing through the restrictor valve hole increases, the common rail pipe and injector The pressure between is balanced. Due to the pressure of the restrictor valve spring 5, the restrictor valve is pushed to the side of the seal seat; however, if an abnormal flow state occurs due to fuel leakage on the injector side, etc., the fuel passing through the restrictor valve hole will be out of balance; this will The restrictor valve is pushed against the restrictor body cone causing the fuel passage to be closed.

The biggest improvement of the utility model lies in that the connection between the common rail pipe 1 and the flow limiting valve assembly is fixed by welding instead of the thread tightening of the utility model, which makes the processing of the internal structure of the flow limiting valve body 4 1. The installation is more convenient, and the disassembly is easier and more convenient when the internal fault of the flow limiting valve body 4 is repaired.

Claims (2)

1. common rail system flow-limiting valve assembly, comprise common rail pipe (1) and flow-limiting valve assembly, it is characterized in that: the current limliting valve body (4) of flow-limiting valve assembly is provided with internal thread with the inwall of common rail pipe (1) connecting end, common rail pipe (1) is provided with outside thread with the connecting end of current limliting valve body (4), internal thread and outside thread match each other, and current limliting valve body (4) is provided with sealing seat (2) with the jointing of common rail pipe (1).

2. a kind of common rail system flow-limiting valve assembly according to claim 1, it is characterized in that: the flow-limiting valve assembly comprises: sealing seat (2), flow-limiting valve (3), current limliting valve body (4), flow-limiting valve spring (5);

Current limliting valve body (4) endoporus is divided into three sections by diameter, and the diameter of three sections endoporus increases from top to bottom successively, forms the first diameter endoporus, the second diameter endoporus, the 3rd diameter endoporus;

Flow-limiting valve (3) is arranged in the second diameter endoporus, and flow-limiting valve spring (5) is arranged between second diameter endoporus bottom and the flow-limiting valve (3), and flow-limiting valve spring (5) is in its pre-compressed state,

There is a sealing cone the first diameter endoporus and the second diameter endoporus jointing place, sealing cone and flow-limiting valve (3) upper end coupling; There is an axial notch flow-limiting valve (3) lower end, and radial direction through hole is arranged at flow-limiting valve (3) top, and radial direction through hole is communicated with the axial notch and the second diameter endoporus of flow-limiting valve (3) lower end;

Sealing seat (2) is arranged in the 3rd diameter endoporus, fits with the 3rd diameter endoporus bottom in sealing seat (2) upper end, and sealing seat (2) lower end is the conical surface;

Common rail pipe (1) is a horn-type opening with the bore openings end of current limliting valve body (4) joint, the conical surface of sealing seat (2) lower end and the coupling of the horn-type opening on the current limliting valve body (4);

Sealing seat (2) axial centre is provided with through hole, and the axial hole of sealing seat (2) is communicated with common rail pipe (1) endoporus and the second diameter endoporus.

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