A hole-type fuel injector for controlling the injection stability of a commercial vehicle diesel engine with a small amount of fuel

Abstract

The invention discloses a hole type oil nozzle for controlling low-oil-amount spraying stability of a commercial vehicle diesel engine. The hole type oil nozzle comprises a needle valve and a needle valve body, the head of the needle valve is composed of two stairs, the height of the first stair is 0.2-0.8 time the maximum lift range of the needle valve, and the diameter of the first stair is slightly larger than that of the second stair; in the small needle valve lift range, the annular circulating sectional area of fuel oil between the head of the needle valve and the needle valve body in a pressure chamber is decreased to be smaller than the spraying hole area, and then precise control over small-flow fuel oil spraying is achieved; the inner diameter of the upper portion of the needle valve body is the same as the outer diameter of the needle valve and is in clearance fit with the outer diameter of the needle valve, and then an axial sealing surface for high-pressure fuel oil is formed; an oil nozzle sealing conical surface used for controlling high-pressure fuel oil spraying is formed by a conical body arranged on the lower portion of the needle valve body and a boss arranged on the head of the needle valve; the outer diameter d2 of the lower portion of the needle valve body of the oil nozzle ranges from 11 mm to 13 mm. According to the hole type oil nozzle, the low-oil-amount fuel oil flowing performance of the oil nozzle and the low-oil-amount spraying stability are improved while the spraying reliability and power performance under the condition of the high circulating oil supply amount are guaranteed.

Description

technical field [0001] The invention relates to a fuel supply system for a commercial vehicle diesel engine, in particular to a hole-type fuel injection nozzle for controlling fuel injection stability when the commercial vehicle diesel engine has a small amount of fuel. Background technique [0002] In order to meet the increasing performance and emission requirements of diesel engines, electronic control has become an inevitable trend. The core of the electronic control of the diesel engine is the electronically controlled fuel injection system, and the common rail injector is the most critical and precise assembly in the electronically controlled common rail system. As well as the consistency requirements for basic parameters such as fuel injection volume and fuel injection duration under different working conditions, it is necessary to continuously optimize its structure and parameters. [0003] The fuel injector is an important part in the fuel system of a diesel engine...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the problem of small fuel injection stability of traditional diesel engine orifice injectors, the present invention discloses a novel orifice injector. By rationally designing the structure and size of the needle valve head of the orifice injector, the needle valve The head is a stepped cylinder. When the needle valve lift is small, it can ensure the minimum flow cross section between the needle valve and the pressure chamber, so as to realize the precise control of the injection volume of the injector needle valve with small lift. When the valve has a large lift, the minimum flow cross-sectional area is only controlled by the cross-sectional area of ​​the injection hole, thereby improving the stability of the fuel injection and improving the reliability of the nozzle; while ensuring the injection performance of the large cycle fuel injection volume, it can Effectively improve the injection stability when the oil volume is small, and reduce the volume of the pressure chamber at the same time, which can reduce HC and soot emissions, and improve the economy and overall performance of the diesel engine

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