JPS5812468B2 - Nozzle touch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection nozzle device for a diesel engine, and its purpose is to be able to obtain stable injection start and end, and to cool the nozzle with fuel oil. It is an object of the present invention to provide a fuel injection nozzle device which not only has increased effectiveness and can prevent secondary injection but also gearbitation erosion.

Hereinafter, the present invention will be explained with reference to the drawings.

Reference numeral 1 in the drawings indicates a nozzle body, and a needle valve accommodating portion 4 of this nozzle body 1 is formed with an auxiliary pressure accumulation chamber 2 and a pressure accumulation chamber 3.

A needle valve 5 is accommodated in the needle valve accommodating portion 4 .

In the large diameter portion 5a of the needle valve 5, one or more guide passages 6 which are long in the vertical direction are formed at regular intervals in the circumferential direction.

The guide path 6 is not formed in the upper and lower end portions 5b and 5c of the large diameter portion 5a of the needle valve 5.

A guide hole 7 is formed in the nozzle body 1 to introduce fuel from the injection pipe into the pressure accumulation chamber 3.

Further, 8 in the drawing is a nozzle hole.

When the fuel is introduced from the pump into the conduit 7 through the injection pipe and supplied to the pressure accumulator 3, the fuel enters the sub-accumulator 2 through the conduit 6, which corresponds to the pressure accumulator when the needle valve is seated. The volume becomes the pressure accumulation chamber 3 + sub-pressure accumulation chamber 2 and becomes larger.

Therefore, sufficient fuel pressure can be stored.

For this reason, even when the needle valve 5 opens and injection begins, a sudden pressure drop in the pressure accumulator 3 does not occur.

Furthermore, when the pressure wave of the subsequent fuel reaches the pressure accumulation chamber 3 and the needle valve 5 is raised, the large diameter portion 5a of the needle valve 5 is attached to the partition wall 9 between the pressure accumulation chamber 3 and the sub-accumulation chamber 2, as shown in FIG. The lower end portions 5c of the fuel storage chambers 3 and auxiliary pressure storage chambers 2 are in contact with each other, and the communication between the pressure storage chambers 3 and the auxiliary pressure storage chambers 2 is cut off, and the pressure waves of the fuel are effectively injected from the injection holes 8.

When the needle valve 5 further rises, as shown in FIG. Recess 10
As a result, the pressure in the subaccumulator 2 drops to a value close to atmospheric pressure.

The fuel discharged into the recess 10 passes through the spill pipe and also flows to the pump inlet, fuel tank, etc.

This amount is larger than that of conventional fuel injection nozzle devices, and the effect of cooling the nozzle by the fuel oil increases.

When the amount of injection is greater than the amount of fuel reaching the pressure accumulation chamber 3, the needle valve 5 descends due to the pressure drop in the pressure accumulation chamber 3.

When the pressure accumulation chamber 3 and the auxiliary pressure accumulation chamber 2 communicate with each other via the conduit 6 due to the lowering of the needle valve 5, the pressure in the pressure accumulation chamber 3 suddenly decreases to below the needle valve pressure, and the needle valve 5 is immediately seated. The injection ends.

As a result, a smaller amount of pump delivery valve suction is required than when a conventional nozzle device is used, and cavitation erosion is less likely to occur.

Further, after the end of injection, the pressure wave of the fuel that reaches the pressure accumulation chamber 3 does not immediately rise to the needle valve opening pressure because the volume equivalent to the pressure accumulation chamber is large, and therefore secondary injection does not occur.

The present invention has been described in detail above, and the needle valve 5 is attached to the large diameter portion 5a of the needle valve 5 accommodated in the needle valve accommodating portion 4 of the nozzle body 1.
When seated, the auxiliary pressure accumulator 2 and the pressure accumulator 3 are communicated, and when the needle valve 5 is opened, the communication between the auxiliary pressure accumulator 2 and the pressure accumulator 3 is cut off, and when the needle valve 5 is at its maximum rise, the auxiliary pressure accumulator 2 is Since the conduit 6 is formed to communicate between the fuel oil and the spill pipe side, a stable injection start and end can be obtained, the nozzle cooling effect by the fuel oil is increased, and secondary injection is prevented. Not only that, but capitation erosion can be prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIGS. 3 and 4 are explanatory views of its operation. . 1 is a nozzle body, 2 is an auxiliary pressure accumulator, 3 is a pressure accumulator, 4 is a needle valve accommodating part, 5 is a needle valve, 5a is a large diameter part, and 6 is a conduit.

Claims (1)

[Claims] 1 Needle valve 5 accommodated in needle valve accommodating portion 4 of nozzle body 1
When the needle valve 5 is seated, an auxiliary pressure accumulation chamber 2 and a pressure accumulation chamber 3 are formed in the large diameter portion 5a of the needle valve 5.
When the needle valve 5 is open, the communication between the auxiliary pressure accumulator 2 and the pressure accumulator 3 is cut off, and when the needle valve 5 is at its maximum rise, the auxiliary pressure accumulator 2
1. A fuel injection nozzle device characterized in that a conduit 6 is formed which communicates between the side of the fuel injection nozzle and the side of the spill pipe.