Common rail having orifice

Abstract

A bush incorporated in a common rail is formed with a smallest diameter orifice having a small inner diameter and an adjacent orifice having an inner diameter larger than that of the smallest diameter orifice on an inner peripheral face of the bush. A press-fitted portion, which is press-fitted into an inside-outside communication hole, and a non-press-fitted portion, which has a smaller outer diameter than the press-fitted portion, are formed on an outer peripheral face of the bush. The smallest diameter orifice and the press-fitted portion are deviated from each other in an axial direction of the bush to prevent an overlap in a radial direction of the bush. Thus, even if the bush is tightly press-fitted into the inside-outside communication hole, decrease of the inner diameter of the smallest diameter orifice can be averted.

Description

technical field [0001] The present invention relates to a common rail installed in an accumulator-type fuel injection device for accumulating high-pressure fuel. Background technique [0002] An accumulator fuel injection device is known as a fuel supply device for an internal combustion engine such as a diesel engine for pressurizing fuel drawn from a fuel tank using a pump and supplying the fuel by injection from an injector into a combustion chamber of each cylinder of the engine. The accumulator-type fuel injection device has a common rail for accumulating high-pressure fuel discharged from a fuel supply pump. The accumulator type fuel injection device distributes the high-pressure fuel accumulated in the pressure accumulator of the common rail to a plurality of injectors installed in each cylinder of the engine, and injects the fuel from the injection holes formed in the axial tips of the injectors into the combustion chamber of each cylinder of the engine. [0003] A...

AI Technical Summary

Problems solved by technology

In this common rail, it is difficult to select the spring constants of the first and second springs for attenuating pressure pulsations and reflected waves

For example, it is difficult to decide which spring should increase the spring constant of the first spring and the second spring

Therefore, the pressure wave (discharge pulsation of the fuel supply pump and reflected wave from the injector) that significantly affects the characteristics of the injection quantity (injection timing, injection quantity, injection ratio, etc.) of each cylinder of the engine cannot be sufficiently limited Small

[0019] Thus, the effect of pressure pulsations in the pressure accumulator of the common rail on the valve opening timing, valve closing timing and fuel injection pressure of the same cylinder or other cylinders cannot be eliminated

Therefore, the difference in injection pressure or the injection amount between cylinders cannot be sufficiently limited to be small.

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