Plane opening and closing type diesel engine high-pressure common rail oil sprayer

Abstract

The invention relates to a plane opening and closing type diesel engine high-pressure common rail oil sprayer. A seal ball in a control valve coupler is a plane seal ball; an annular seal plane, a throttling pit, a throttling hole and a rapid pressure relief structure are arranged on the upper end of a guide valve seat; the diameter of the seal plane of the plane seal ball is equivalent to the outer diameter of the annular seal plane; and the hardness, planeness and surface roughness of the seal plane and the annular seal plane reach the design requirement. Because a seal steel ball in the control valve coupler is changed into the plane seal ball with a seal plane, the seal form of the throttling taper hole on the upper end surface of the guide valve seat is changed into plane seal, and the rapid pressure relief structure is added, the invention ensures that high-frequency opening and closing seal performance is high and the machining process of a sealing element is greatly enhanced, can be finished through adopting the conventional gold processing and heat treatment, has high processing efficiency and stable and reliable seal performance and rapid pressure relief performance, and is an improvement of the traditional products of the Germany Bosch company.

Description

Technical field: [0001] The invention relates to a high-pressure common rail fuel system of a diesel engine, in particular to a high-pressure common rail fuel injector. Background technique: [0002] Common Rail EFI technology refers to a fuel supply method that completely separates the generation of injection pressure from the injection process in a closed-loop system composed of a high-pressure oil pump, a pressure sensor and an electronic control unit (ECU). It uses a high-pressure oil pump to deliver high-pressure fuel to the public fuel supply pipe (Rail), and realizes precise control through the oil pressure in the public fuel supply pipe, so that the pressure of the high-pressure fuel pipe (Pressure) has nothing to do with the engine speed, which can greatly reduce the fuel consumption of the diesel engine. The degree to which fuel supply pressure varies with engine speed. [0003] At present, there are three major companies in the world producing high-pressure commo...

AI Technical Summary

Problems solved by technology

[0007] from figure 1 According to the sealing structure between the control valve coupler 6 and the valve assembly 7 and the sealing principle of the two, the control valve coupler 6 and the valve assembly 7 are matched by the line contact between the sealing steel ball 64 and the throttling cone hole 73 Sealed, the diameter of the sealing steel ball 64 is 1.33mm ~ 1.34mm, the diameter of the line seal formed by the contact between the throttle cone hole 73 and the sealing steel ball 64 is about 0.68mm, in order to ensure that the valve cone surface has a good The machining accuracy must be ground by the world's top high-speed grinding machine, and its grinding speed is 120,000r / min. Even so, it is difficult for the throttling taper to meet the design requirements. The diameter is only 0.68mm. Although the speed of the grinding head is extremely high, the grinding line speed here is only 4.3m / s, which cannot meet the requirements of high-precision grinding, and the distance between the processed cone surface and the grinding head The friction force is very large, the high temperature of grinding is easy to anneal the cone surface and reduce the hardness, and the machining accuracy of the throttling cone hole is difficult to meet the design accuracy requirements

[0008] During the frequent opening and closing of the high-pressure common rail injector, the sealing steel ball 64 repeatedly contacts and separates with the throttle cone 73 along with the moving spool 62. During this movement, the sealing steel ball 64 and the joint The actual sealing line formed by the contact of the flow cone hole 73 is constantly changing. Since the surface roughness, surface hardness, roundness and straightness of the flow cone hole 73 are difficult to meet the design requirements, it is difficult to ensure the opening and closing of the two. Reliability; in the process of frequent opening and closing, the sealing steel ball 64 itself will rotate and easily deform, which will lead to unstable sealing; due to the high oil pressure of the system, the high-pressure oil beam continuously washes the throttle cone when it is in the open state The cone surface of the hole 73 will be washed out for a long time to form irregular fine shallow grooves, resulting in a decrease in sealing performance; in addition, the sealing steel ball 64 is installed in the center hole of the lower end surface of the movable valve core 62, and the throttling The tapered hole 73 is set on the upper end surface of the pilot valve seat 71, and the axis of the two always deviates, which is easy to produce unilateral contact, thus affecting the sealing performance of the closure

[0009] Through the above objective analysis, it can be seen that in the existing high-pressure common rail injector for diesel engines, the design of the sealing structure between the control valve coupler 6 and the valve assembly 7 is unreasonable, the technical requirements for the throttling cone hole 73 are high, and the processing is difficult. Conventional grinding machines cannot be used for processing, and the introduction of the entire production line requires a large investment, which is difficult for domestic general oil pump nozzle manufacturers. Even if the entire production line is introduced, the operator's technical level is difficult to adapt

This kind of sealing structure will inevitably lead to low product yield, poor sealing stability, short service life, high product price, and unbearable for users.

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