JPH0842355A - Sound insulating device of head part of overhead valve type diesel engine - Google Patents

Abstract

PURPOSE:To enable noise of a fuel injection nozzle and a head cover chamber of an overhead valve type diesel engine to be restrained. CONSTITUTION:A nozzle cover 6 and a head cover 2 are integrally formed as a sound insulating cover 7, and the inside of the sound insulating cover 7 is divided into a head cover chamber 10 and a nozzle housing chamber 11 through a partition wall 8. The sound insulating cover 7 has a structure wherein the nozzle cover 6 and the head cover 2 are mutually reinforced through the partition wall 8, and the stiffness of the whole sound insulating cover 7 is enhanced, and sitting noise of a fuel injection nozzle 4 and noise of the head cover chamber 10 can be effectively insulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof device for a head portion of an overhead valve type diesel engine, and provides a soundproof device capable of effectively soundproofing noise generated from a head cover chamber and a fuel injection nozzle.

[0002]

BACKGROUND OF THE INVENTION The basic structure of a soundproof device for a head portion of an overhead valve type diesel engine to which the present invention is applied has a head cover 2 above a cylinder head 1 of a diesel engine E as shown in FIG. 1 or 5. Assembling, the fuel injection nozzle 4 is projected from the upper surface 3 of the cylinder head 1 to the lower part, and the peripheral space 5 of the fuel injection nozzle 4 is covered with the nozzle cover 6.

[0003]

2. Description of the Related Art Generally, in an overhead valve type diesel engine, a large amount of noise is generated by driving a valve operating mechanism housed in a head cover chamber, and a large amount of noise is generated when a needle valve of a fuel injection nozzle is seated on a seat portion (that is, (Seating sound) occurs. Therefore, it is required to reduce the noise generated from both the head cover chamber and the fuel injection nozzle.

Therefore, as a conventional technique having the above-mentioned basic structure adapted to this purpose, as shown in Japanese Patent Laid-Open No. 4-64797 (see FIG. 5), the fuel injection nozzle 4 and the intake manifold 30 are covered with a large nozzle cover. There is a structure in which the outer surface of the head cover 2 is further surrounded by the nozzle cover 6 while being covered with the nozzle cover 6.

[0005]

In the above-mentioned prior art, since the nozzle cover 6 has the double cover structure in which the head cover 2 is housed, the nozzle cover 6 becomes large and the rigidity becomes insufficient, and the fuel injection nozzle 4 There is a risk that noise from the vehicle will be amplified. Further, in the publication, the nozzle cover 6 is for suppressing noise leaking from the head cover 2, the cylinder head 1 and the intake manifold 30,
No mention is made of noise reduction of the fuel injection nozzle 4.

Therefore, the noise of the head cover chamber 10 is reduced by the double protection structure of the head cover 2 and the nozzle cover 6, but the seating noise of the fuel injection nozzle 4 may not be sufficiently shielded by the nozzle cover 6. This is big.

On the other hand, Japanese Utility Model Laid-Open No. 5-948 (see FIG. 4)
Discloses a head cover 2 for covering a spark plug 50 of a spark ignition engine E together with a head cover chamber 10. Therefore, when this technique is applied to a diesel engine which is an object of the present invention, a fuel injection nozzle and a head cover chamber are provided. It is also conceivable to cover one with a head cover to prevent noise.

However, in this case, the head cover 2 becomes large in size and the rigidity of the cover is insufficient.
The noise from the fuel injection nozzle may be amplified. An object of the present invention is to suppress both the noise of the fuel injection nozzle of the overhead valve type diesel engine and the noise of the head cover chamber.

[0009]

Means for achieving the above object will be described below with reference to FIGS. 1 to 3 showing an embodiment. That is, according to the present invention, in the soundproof device for the head portion of the overhead valve type diesel engine having the basic structure, the nozzle cover 6 and the head cover 2 are integrally formed as a soundproof cover 7, and the head cover is provided in the soundproof cover 7 via the partition wall 8. It is characterized in that the chamber 10 and the nozzle accommodating chamber 12 are partitioned and formed. The head portion of the engine means a space above the cylinder head 1 in which a valve operating mechanism such as a fuel injection nozzle and a rocker arm is arranged.

[0010]

The nozzle cover 6 and the head cover 2 are integrated as a soundproof cover 7, a partition wall 8 is provided in the soundproof cover 7, and both sides thereof are a head cover chamber 10 and a nozzle accommodating chamber 12.
As compared with the case where the nozzle cover 6 and the head cover 2 are separately provided, the both covers are so-called partition walls 8.
Since the structures are reinforced with each other, the rigidity of the entire soundproof cover 7 is increased. Therefore, unlike the prior art, the cover that covers the head portion does not have insufficient rigidity, and the noise of the fuel injection nozzle 4 or the like is not amplified.

That is, in the prior art, the head cover 2 has a double structure in which the outside of the head cover 2 is further covered with the nozzle cover 6.
And the nozzle cover 6 are integrated, and the partition wall 8 is erected in the integrated soundproof cover 7. The technical idea of this integration is not disclosed in the above-mentioned prior art.

[0012]

【The invention's effect】

(1) Since the soundproof cover has a structure in which the nozzle cover and the head cover reinforce each other through the partition wall, the rigidity of the soundproof cover as a whole is increased, and the sound insulation performance against the seating noise of the fuel injection nozzle and the noise of the head cover chamber is improved.

(2) Since the nozzle cover and the head cover are integrated into the soundproof cover, the number of parts of the soundproof device can be reduced and the number of mounting points for the cylinder head can be reduced, so that the cost of parts and mounting can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a soundproofing device of a head portion of a vertical three-cylinder subchamber diesel engine, FIG. 2 is a plan view of the soundproofing device, and FIG. 3 is an explanatory view of a main part of a sealing part of a soundproof cover.

As shown in FIG. 1, a rocker arm bracket 12 is erected on an upper surface 3 of a cylinder head 1 of a vertical three-cylinder sub-chamber diesel engine E, and a rocker arm shaft 13 is laterally supported by the bracket 12 to support the rocker arm shaft 13. Thirteen
The rocker arm 14 is pivotally supported on the rocker arm 14. The upper end of the push rod 15 is connected to the input portion 14a of the rocker arm 14.
In addition, the output portion 14b of the rocker arm 14 is interlocked with the open / close valve 16, and the open / close valve 16 can be opened / closed by swinging the rocker arm 14. On the other hand, the cylinder head 1 has a sub chamber
(Not shown) is formed, and the fuel injection nozzle 4 is inclinedly projected from the upper surface 3 of the cylinder head 1 toward the sub chamber.

As shown in FIGS. 1 and 2, the head cover 2 for accommodating the valve operating mechanism 17 such as the rocker arm 14 and the opening / closing valve 16 and the nozzle cover 6 for accommodating the fuel injection nozzles 4 have a soundproof cover 7 therein. Is integrally formed by casting. That is, the valve operating mechanism 17 and 3 arranged in the front-back direction
A bowl-shaped soundproof cover 7 is formed so as to cover the entire fuel injection nozzles 4, and a partition wall 8 is erected in the soundproof cover 7 in the front-back direction. Is divided into a head cover chamber 10 and a nozzle accommodating chamber 11 via a partition wall 8, the valve operating mechanism 17 is arranged in the head cover chamber 10, and the fuel injection nozzle 4 is disposed in the nozzle accommodating chamber 11.
To place.

As shown in FIGS. 1 to 3, the soundproof cover 7 and the partition wall 8 are brought into close contact with the upper surface 3 of the cylinder head 1 via a rubber sealing material 18. As shown in FIG. 3, the lower surface 1 of the sealing material 18 in contact with the cylinder head upper surface 3 of each portion of the sealing material 18 facing the fuel injection nozzle 4.
8a, the split groove 21 is cut out upward, and the insertion hole 22 is opened laterally at the upper end of the split groove 21.
A fuel pipe 20 that connects the fuel injection pump 19 with the fuel injection pump 19 is passed through the insertion hole 22 of the sealing material 18 through the split groove 21 so as to maintain the hermeticity in the nozzle housing chamber 11.

The function of the soundproofing device for the head of the vertical three-cylinder subchamber diesel engine of this embodiment will be described. The nozzle cover 6 shown in the above-mentioned conventional technique (see FIG. 5)
Since the head cover 2 and the head cover 2 are integrated as the soundproof cover 7 and the head cover chamber 10 and the nozzle accommodating chamber 12 are formed in the soundproof cover 7 with the partition wall 8 interposed therebetween, the partition 2 is divided as compared with the case where the both covers 2 and 6 are separately provided. Since the walls 8 reinforce each other, the rigidity of the entire soundproof cover 7 increases.

Therefore, unlike the prior art, the soundproof cover 7 does not have insufficient rigidity and the noise of the head portion is not amplified, and the seating sound of the fuel injection nozzle 4 and the valve operating mechanism 17 are used. The noise of the head cover chamber 10 can be strongly insulated.

Since the present invention is intended for an overhead valve type diesel engine, it is applicable not only to the sub-chamber type diesel engine as in the above embodiment but also to a direct injection type diesel engine. Further, the present invention can be applied regardless of a vertical diesel engine having a vertical cylinder and a horizontal diesel engine having a horizontal cylinder.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a soundproof device for a head portion of a vertical three-cylinder subchamber diesel engine showing an embodiment of the present invention.

FIG. 2 is a plan view of the soundproof device.

FIG. 3 is an explanatory view of a main part of a sealing portion of the soundproof cover.
3A is a vertical sectional view of the sealing material, and FIG. 3B is a front view of the sealing material.

FIG. 4 is a vertical cross-sectional view around a head cover of a spark ignition engine.

FIG. 5 is a view equivalent to FIG. 1 showing the prior art.

[Explanation of symbols]

1 ... Cylinder head, 2 ... Head cover, 3 ... Cylinder head upper surface, 4 ... Fuel injection nozzle, 5 ... Fuel injection nozzle peripheral space, 6 ... Nozzle cover, 7 ... Soundproof cover, 8
... Partition wall, 10 ... Head cover chamber, 11 ... Nozzle housing chamber, E ... Overhead valve type diesel engine.

Claims (1)

[Claims] 1. A head cover (2) is assembled above a cylinder head (1) of a diesel engine (E), and a fuel injection nozzle (4) is projected from a top surface (3) of the cylinder head (1) to a lower part to remove fuel. A soundproof device for a head portion of an overhead valve type diesel engine, wherein a space (5) around an injection nozzle (4) is covered with a nozzle cover (6), wherein the nozzle cover (6) and the head cover (2) are soundproof covers.
It is integrally formed as (7) and has a partition wall inside the soundproof cover (7).
The head cover chamber (10) and the nozzle housing chamber (1
A soundproofing device for a head portion of an overhead valve type diesel engine, which is characterized in that (2) is divided and formed.